CA1042868A - Gluconic acid in preparation of raney copper catalyst - Google Patents

Abstract

ABSTRACT OF THE INVENTION
An improved process for making acrylamide from a composition of acrylonitrile and water utilizing an improved Raney copper catalyst. This catalyst is prepared by contacting particulate copper/aluminum alloy particles with an aqueous solution containing dissolved therein both alkali metal hydroxide and hydroxyl containing hydrocarbon compound having at least three carbon atoms per molecule and further having at least three oxygen containing groups per molecule.

Description

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~ACKGROUND OF THE INVENTION
In the art of catalytically hydrolyzing acrylonitrile with water to acrylamide, various copper and copper containing catalysts have been proposed, such as mixtures of copper oxide ;~
with other metal oxides, reduced copper oxide/metal oxide mix- ::
.` tures, copper and copper/metal mixtures (see United States : .
~. Patents Nos. 3,597,481; 3,631,104; 3,642,894; and 3,642,643). : :
. The use of Raney copper catalysts for this purpose is shown in I German Patent No. 2,036,126, German DOS 2,164,185 (1972), and .:~ . -jA 10 Canadian Patent No. 839,384 (1972). Based upon the method of catalyst preparation, it would appear that such prior art can .; be catalog~ed into two groups, one group involving the reduction -.. . . . .
, of a copper containing compound or compounds, the other group .
j involving the activation of a copper or copper alloy (such as ., ~. ,, .. ,-; .
Raney copper). :
So far as can be determined, when using a Raney copper catalyst to hydrolyze acrylonitrile to acrylamide by the teachings of the prior art, it has been the practice to prepare :~
~ or activate such catalyst by contacting such in a particulated ~
3 20 form solely with aqueous caustic to dissolve away at least a :
`~ portion of the aluminum after which the resulting activated t product lS kept under water or inert solvents to avoid oxidation.
. Apparentiy complete aluminum.~emoval was heretofore sometimes 1~4Z868 believed to have been achieved and to be desirable for purposes of enhancing catalyst activity for this intended hydrolysis reaction; see, for example, the above referenced Canadian Pat. No. 839,384 at p.5 where the Kawaken Fine Chemicals Co.
Raney copper catalyst is usedO According to Kawaken Fine Chemical Co. trade literature, it appears that substantially complete aluminum removal is achieved.
The art theorizes that Raney catalysts can contain amounts of insoluble aluminates which are sufficient to adversely afect catalyst activity and life for whatever reason, and the art has described efforts to remove such impurities; see, for examples, United States Patents Nos. 2,673,189; 2,604,455;

2,950,260; and British patents Nos. 642,861 and 658,863.
Apparently, no one has ever heretofore used a catalyst so pre-pared as to minimize the presence of alumina for catalytically hydrolyzing acrylonitrile to acrylamide under aqueous liquid phase conditions.
` It has heretofore been proposed to active Raney alloys for use as fuel cell electrodes by using in the activat-ing solution alkali metal tartrates or lower aliphatic amino ~ compounds; see United States Patent No. 3,235,513. See also - United States Patent No. 3,067,276 for a discussion of catalyst ;; regeneration~ No one has ever heretofore prepared a Raney copper catalyst so activated in the presence of an additive and then used such a catalyst to catalytically convert acrylonitrile ~ to acrylamide under aqueous liquid phase conditions.

-3 Because of the limitations and short-comings observed for prior art Raney copper catalysts, the art continues to seek a Raney copper catalyst adapted for use in such hydrolysis reaction which has a high initial activity and a long activity life. In . ~ , , .

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)42868 particular, the art desires such a catalyst which is particular-ly weli suited for hydrolyzing acrylonitrile to acrylamide using a concentrated acrylonitrile/water feed and employing a rapid conversion rate while achieving a high conversion level.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to an improved - catalytic process for making acrylamide from a starting composition comprising acrylonitrile and water. Typically, such a composition comprises from about 10 to 75 weight per-cent (preferably 30 to 40 weight percent) acrylonitrile with the remainder to 100 weight percent thereof being water. The process is conducted under liquid phase conditions using ,~ temperatures in the range from about 6G to 150C., with tem-peratures of from about 70 to 125C being presently preferred. ~
Any convenient process conditions and procedure may be employ- -ed as those skilled in the art will appreciate.
The process involves contacting such a composition with a Raney copper catalyst. This catalyst is one which has been prepared by contacting particles of a metal alloy comprised of copper and aluminum with an aqueous solution which has dis-solved therein on a 100 weight percent total solution basis from greater than 0 to about 50 weight percent alkali metal hydroxide and from greater than 0 to about 25 weight percent of at least one hydroxylated ~' ~ ` 3 ,' ' ' '.

. ' ' ' .:

hydrocarbon compound.
Thus in a first aspect this invention provides a process for the preparation of a Raney copper catalyst which comprises contacting part-icles of a metal alloy containing aluminum and copper in a weight ratio of from about 70:30 to about 30:70 together with adventitious ~mpurities, with an aqueous solution which has dissolved therein on a 100 weight percent total by-product free solution basis from greater than 0 to about 25 weight percent aIkali metal hydroxide and from about greater than 0 to about 25 weight percent, or the solubility limit thereof in water, whichever is lower, of at least one hydroxylated hydrocarbon compound of formula I

-(Rl)x(R2)y(R3)z .. wherein:
(a) A represents a linear or branched alkyl group of three to eight carbon atoms;
(b) x + y + z is an integer of three to six inclusive;
.: (c) Rl, R2 and R3 are hydrogen-oxygen functions sufficient to provide hydroxyl group, carbonyl group or carboxyl group functions in the .~ alkyl group without increasing the number of carbon atoms present, or are groupings which hydrolyse under alkaline conditions to provide said hydroxyl carbonyl and carboxyl functions, provided that at least two of Rl, R2 and R3 : are such as to provide different functional groups in the aIkyl group A, and that at least one of said groups is hydroxyl, said contacting being carried ~
out at a temperature below about 80 &. ~ .
In an alternative aspect this invention provides a process for mak~ng acrylamide from acrylonitrile compris~ng the steps of: :
(A) activating a Raney copper catalyst through contact of aqueous alkali metal hydroxide with a metal alloy in particulate form and comprised of :
copper and aluminum in a weight ratio of from about 70:30 to 30:70 together ..
~ with adventitious impurities, thereby to remove from such alloy particles at -~ 30 least about 25 weight percent of the aluminum initially present therein, at ~ least a portion of such contacting being conducted over a time interval of -. from 1/2 to 30 hours using an aqueous alkali metal hydroxide solution which , ~ ~ 3 104Z868 `-additionally has dissolved therein a compound of formula I ~`

(Rl)x(R2)y(R3)zA

wherein:
.~. (a) A represents a linear or branched alkyl group of three to eight carbon atoms;
(b) x + y + z is an integer of three to six inclusive;
(c) Rl, R2 and R3 are hydrogen-oxygen functions sufficient to provide hydroxyl group, carbonyl group or carboxyl group functions in the alkyl group without increasing the number of carbon atoms present, or are groupings which hydrolyse under alkaline conditions to provide said hydroxyl ..
carbonyl and carboxyl functions, provided that at least two of Rl, R2 and R3 are such as to provide different functional groups in the alkyl group A, and ~:
' that at least one of said groups is hydroxyl, said contacting being carried - out at a temperature below about 80C. .
(B) contacting the so activated Raney copper catalyst with an aqueous compo~
sition comprising from about 10 to 75 weight percent acrylonitrile with the remainder up to 100 weight percent thereof being water while m~intaining a ~
, temperature of from about 60 to 150C thereby to hydrolyse at least a portion ~ :
of said acrylonitrile to acrylamide. :-.:
In a preferred aspect this invention provides a process for cat-alytically hydrolysing acrylonitrile to acrylamide by contacting acrylonitrile :.~ ;
.~ . .
in the presence of water with a Raney copper catalyst, the improvement which ~, comprises the steps of:
.2 ~ (A) first contacting an aqueous solution of a hydroxylated hydrocarbon com-pound with a group of metal alloy particles comprised of copper and aluminum, .:~
said hydroxylated hydrocarbon compound being a compound of formula I

(Rl)x(R2)y(R3)zA
wherein:
~. (a) A represen~s a linear or branched alkyl grouP of three to ^, 30 ei~ht carbon atoms;
~ - 3b . '~
, (b) x + y + z is an integer of three to six inclusive, (c) Rl, R2 and R3 are hydrogen-oxygen functions sufficient to provide hydroxyl groups carbonyl group or carboxyl group functions in the alkyl group without increasing the number of carbon atoms present, or are . .
groupings which hydrolyse under alkaline conditions to provide said hydroxyl carbonyl and carboxyl functions, provided that at least two of Rl, R2 and R3 are such as to provide different functional groups in the alkyl group A, and that at least one of said groups is hydroxyl, (1) said solution containing from about 0.01 to 1 weight per-cent of said hydroxylated hydrocarbon compound in dissolved form, :
(2) said group having an average particle size diameter in the range from about 0.001 to 0.5 inch, (3) said alloy having a copper to aluminum weight ratio of from - about 30:70 to 70:30, together with adventitious impurities, ~
. (4) said solution having a temperature in the range from about : ;
0 to 80C, (B) secondly contacting the resulting said group of alloy particles with an aqueous caustic solution, (1) said aqueous caustic solution containing from greater than 0 to about 5 weight percent dissolved alkali metal hydroxide, (2) said contacting being accomplished over a total time inter- :
val of from about 1/2 to 30 hours.
(3) said caustic solution being added gradually to said group over said time interval,

(4) the contact rate of starting caustic solution being added - to said grouP during such contacting being from about .01 to 10 pounds caustic per pound of said starting group of alloy particles per hour, ' (5) the total quantity of caustic so added being in the range of from about 0.5 to 25 pounds of caustic per pound of said starting group of 3 particles, (6) said aqueous caustic solution and the resulting aqueous medium produced in such contacting each having a temperature in the range from - 3c -. .. -- - - . . . ~ , .

o 104Z868 about 0 to 80 C, (7) said group being m~intained in said contact with said sol-ution of said hydroxylated hydrocarbon compound during said contacting with said aqueous caustic solution by admixture of such respective solutions, (C) washing the so-treated group of product particles to separate therefrom remaining unreacted caustic, and ~ :
(D) thirdly contacting at a temperature of from about 60 to 150C the so- ~;
washed group of particles with an aqueous composition comprising from about 10 to 75 weight percent acrylonitrile with the remainder to 100 weight percent , thereof being water.
Preferably the hydroxylated hydrocarbon compound is chosen from the group comprising gluconic acid, malic acid, tartaric acid, citric acid, and glyceraldehyde, or their ammonium or aIkali metal salts or esters thereof.
More preferably the hydroxylated hydrocarbon compound is gluconic acid or its ;~
ammonium or alkali metal salts, or esters thereof.
Preferably the Raney copper catalyst is contacted with alkali metal hydroxide, conveniently sodium or potassium hydroxide, under an inert atmosphere. Conveniently a nitrogen atmosphere is used.
Freferably the metal alloy particles range in size from about 2 0.001 lnch to about 0.5 lnch.

' ;j ~

- - 3d -.( ~
: ' 1~4Z868 The catalyst so prepared characteristically and typically com-prises from about 2 to 45 weight percent aluminum with the balance up to 100 weight percent being copper in any given catalyst. Minor quantities of other materials, such as oxygen, may be present. More preferably, such catalyst comprises, on a 100 weight percent total weight basis, from about 10 to 35 -weight percent aluminum with the balance up to 100 weight percent thereof being copper. This catalyst characteristically and typically has an average particle size (diameter) in the range from about 0.001 to 0.5 inch, though larger and smaller particle sizes may be used if desired.
Because of the characteristically high initial catalytic activity, and also the characteristically long catalytic activity life, associated with the type of catalyst so prepared and used in the process of this invention wherein acrylonitrile is hydrolyzed with water to acrylamide, as indicated above, the present invention provides an improved process which can be oper-ated continuously and for extended periods of time with the same catalyst to produce desired, economically significant, high conversion yields of acryl-amide. The present invention is particularly useful when using starting compositions containing a high, or concentrated, acrylonitrile contentO
; In addition, the process of this invention offers operating efficiencies and economies, particularly in fixed catalyst bed, continuous operation, which are believed to be greater than heretofore known in this art.
The present invention provides an improved technique for activat-ing a Raney copper catalyst in a process for hydrolyzing acrylonitrile to acrylamide under aqueous liquid phase conditions.
Further, the present invention aims to provide a Raney copper catalyst which permits one to hydrolyze acrylonitrile to acrylamide under liquid phase conditions and achieve a high initial activity together with a longer catalyst life than has heretofore been possible in the hydrolysis reaction of acrylonitrile to acrylamide.
; Other and further aims, objects, purposes, advantages, utilities and features will be apparent to those skilled in ~he art from a reading of .

. 104Z868 -- the present specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
._ In the drawings:
Figure 1 is a diagrammatic representation of one mode of preparing a catalyst suitable for the process of the present invention, Figures 2 through 4 each show representations similar to that of Figure 1 but illustrating second, third and fourth modes, respectively, of catalyst preparation; and ;
Figure 5 is a plot illustrating the effect of additives such as ~-~
used in Raney copper catalyst activation by this invention upon Raney copper catalyst activity in acrylonitrile hydrolysis to acrylamide.
DETAILED DESCRIPTION
The catalyst used in the practice of the present invention is a Raney copper catalyst which has been activated through contact with a composi-tion containing dissolved alkali metal hytroxide and dissolved hydroxylated hydrocarbon compound. The starting material is a preformed, binary metal alloy comprised of aluminum and copper in particulate form which contains a weight percent ratio of Al/Cu in the range from about 70:30 to 30:70 (prefer-ably about 45:55 to 55:45, and most preferably about 50:50).
In general, in this invention, no particular special conditions need be employed when contacting starting alloy particles with an aqueous solution of alkali metal hydroxide and hydroxylated hydrocarbon compound.
Typically, the alloy starting material is as indicated in the form of particles ranging in size from about 0.001 to 0.5 inch. Preferably, this solution comprises from greater than 0 to about 30 weight percent alkali metal hydrox-ite, from greater than 0 to about 20 weight percent hydroxylated hydrocarbon compound, and with the balance up to 100 weight percent thereof being water (total composition basis). More preferably, such a solution comprises from greater than 0 to about 10 weight percent alkali metal hydroxide, from about 0.01 to about 1.0 weight percent hydroxylated hydrocarbon compound, and with the balance up to 100 weight percent thereof (total basis) being water.
.. :: .
Preferably, the process of contacting with such a solution is conducted while . :

maintaining the reaction zone in the region of the particles being activated into Raney copper catalyst at a temperature in the range of from about 0 to 100C. Preferably, the contacting time ranges from about 1/2 to 30 hours.
More preferably, the contacting temperature is in the range of from about 30 to 60C. More preferably, the contacting time is adjusted to be in the range from about four to twelve hours.
The Raney copper catalyst should have at least about 25 weight percent of the initially present aluminum in such alloy particles is removed during alkali contacting; however, it is apparently not necessary to remove sluminum from a catalyst during activation thereof by contacting such with a mixed solution of alkali metal hydroxide and hydroxylated hydrocarbon compound as taught by this invention.
; In one preferred and exemplary plant operational mode of catalyst preparation, activation of such starting alloy is accomplished by first con-tacting an aqueous solution of at least one hydroxylated hydrocarbon compound with a group of such alloy particles. This aqueous solution can contain dis-solved therein from about 0.01 to 1.0 weight percent of hydroxylated hydro-carbon compound (total solution basis). Conveniently, the particles are preferably initially immersed in water and the hydroxylated hydrocarbon com-pound(s) is (are) added to such water of immersion until the desired concen-tration of such compound(s) is obtained. Such alloy particle group has an average particle size (diameter) in the range from about 0.001 to 0.5 inch, and such copper alloy preferably has a copper to aluminum weight ratio of from about 45:55 to 55:45. This aqueous solution has a temperature in the range from about 30 to 60C during such contacting. The time of such first contacting is relatively unimportant, though times of from about 5 minutes up to several hours have been found to be convenient.
, Secondly, one contacts the resulting said group of alloy particles with an aqueous caustic (alkali metal hydroxide) solution. Conveniently, the - ~-caustic (alkali metal hydroxide) is added to (and dissolved in) the previously utilized solution of hydroxylated hydrocarbon compound(s) while continuous contact of such solution with such particles is maintained. Such second ., :
, ~' .

contacting is accomplished over a total time interval of from about 1/2 to 30 hours (preferably about 4 to 12 hours), and such caustic solution may be added gradually to said group over said time interval continuously or in-crementally. The contact rate or addition rate of starting caustic solution being added to said group of particles during such contacting typically ranges from about 0.01 to 10 pounds caustic per pound of said starting group of alloy particles per hour (dry weight basis). The total quantity of caustic so added to the aqueous medium in the reaction zone is typically in the range of from about 0.5 to 25 pounds of caustic per pound of said starting group of particles (dry weight basis). During such contacting, such aqueous caustic solution and the resulting aqueous medium produced in such contacting each have a temperature in the range from about 0 to 100C. During such second contacting, said group of particles is thus maintained in contact with at least one hydroxylated hydrocarbon compound. Preferably at least about 25 weight percent (total starting weight basis) of this aluminum initially present is removed during such a contacting operation conducted in accord with the teach-ings of this invention during the course of such an initial catalyst operation using fresh starting alloy particles.
While some alkali metal hydroxide during the contacting character-istically reacts with the aluminum of the alloy particles, the manner in which a hydroxylated hydrocarbon compound functions in the practice of the present invention is presently unknown. One theory (and there is no intent herein to be bound the theory) is that this material functions as a sequestering or - stabilizing agent which prevents the precipitation of solid particles of ; alumina ~qr derivatives) on the surface or in the pores of the catalyst, a theory which may be supported by United States Pat. No. 2,345,134 where poly-hydroxylated compounds apparently act as stabilizing agents for sodium alumin-ate.
After such second contacting, the resulting group of Raney copper catalyst particles is preferably washed to separate therefrom any remaining hydroxylated hydrocarbon compound, the remaining unreacted caustic and aluminate. Thereafter, the so-washed group of particles may optionally inter--veningly be stored before being used in the hydrolysis process of this invention.
This hydrolysis process preferably involves contacting such par-ticles of Raney copper catalyst with an aqueous composition comprising, for - example, from about 30 to 40 weight percent acrylonitrile with the remainder to 100 weight percent thereof being water while maintaining a temperature of, for example, from about 70 to 125C, as indicated.
Ore preferred group of hydroxylated hydrocarbon compounds comprise polyhydroxylated aliphatic carboxylic acids. One class of such acids suitable for use in the present invention is characterized by the formula II
R~ R"' I
R - - C - - C - ~ COOH II
R' m R"" n where: R, R', R", R"' and R"" are each independently H, lower alkyl, -OH, or . -COOH provided that at least one of R, R~, R", R~ and R"" is hydroxyl and that at least one other of such RJ R', R~, R"' and R"" groups is either carboxyl or hydroxyl, n is an integer of from 2 through 8 (4 through 8 being preferred), ; m is an integer of from 0 through 4.
It will be readily appreciated by those skilled in the art that one can employ, in place of, or in addition to, those compounds of formula II
carboxylate salts ~such as alkali metal salts and ammonium salts) and carboxy-; 20 late esters (such as lactones and esters with lower aliphatic alcohols) which will, in alkaline water solution, form the same anions as do the compounds of formula 1.
Examples of particular compounds within the scope of formula II
include: gluconic acid, glucaric acid, saccharinic acid, and the like. ~ ;
One more preferred class of hydroxylated hydrocarbon compounds within the scope of formula (1) above is characterized by the formula III: -~
R - (CHOH) COOH III ~ ;
where: R is selected from the group consisting of -CH3, -CH2OH, -COOH, -CHO, and -H, and n is an integer of from 1 through 5.
~ - 8 - ; ~ ~
.. '-` '-. , . -, ~ ~ ;, . . . - .,, , . ~ . . - . - - - . . :. . , - Examples of particular compounds within the scope of formula III
include gluconic acid, glucaric acid, tartaric acid, d-glucuronic acid, and the like.
Examples of compounds suitable for use as additives during contact- -ing in accord with the teachings of this invention which are similar to compounds within the scope of formula II or of formula III include alkali metal salts (sodium being presently preferred) of gluconic acid, tartaric acid, or citric acid, lactones, such as glucono-~-lactone, and the likeO
Preferred hydroxylated hydrocarbon compounds are substantially completely water soluble at the concentrations employed in the usual practice of this invention.
Presently the mos~ preferred hydroxylated hydrocarbon compound is gluconic acid (and compounds which produce the gluconate ion in alkaline water solution, such as sodium gluconate, glucono-~-lactone, and the like) sorbitol.
~: A presently most preferred alkali metal hydroxide is sodium hydroxide.
Those skilled in the art will readily appreciate that any con-;-` venient procedure or technique may be employed for contacting starting copper/
aluminum alloy particles with an aqueous mixture of alkali metal hydroxide - and hydroxylated hydrocarbon compound. The starting alloy particles can be 3 2Q added to a starting mixture composition, or vice versa, or otherwise as desir-ed. While pretreatment of particles of alloy with a starting mixture com-prising an aqueous solution of hydroxylated hydrocarbon compound is more convenient, such is not necessary. A performed Raney copper catalyst conven~
tionally prepared by alkali contact can be post treated, if desired, with a starting solution comprised of alkali metal hydroxide and hydroxylated hydro-carbon compound in accord with the teachings of this invention particularly when optimized catalyst performance is not needed. It is preferred to activate a catalyst as taught herein for use in this invention under conditions such that the metal particles are subjected to a minimum of heat exposure, such as is generated when, for example, concentrated aqueous alkali metal ~ ;
hydroxide contacts the starting alloy particles. It is preferred to activate a catulyst as taught herein for use in this invention using temperatures which .~ ~

do not exceed about 80C. and by using controlled incremental or continuous addition of alkali metal hydroxide over an extended time period to an aqueous medium being used to activate a group of particles.
One can conveniently employ during catalyst activation a total quantity of aqueous hydroxide, for example, such that the molar quantity of hydroxide used totals from about 1.5 to 2.0 times the total molar amount of aluminum it is desired to leach away, as when a batch preparation procedure is being employed, where the aqueous hydroxide is being added to a vessel containing a fixed quantity of starting alloy with aqueous hydroxylated hydro-carbon compound and the aqueous hydroxide leaching composition being allowed to accumulate in this vessel during the leaching operation.
During the contacting of starting alloy with such a leachingcomposition, an aluminate (in solution) and hydrogen gas are characteristical-ly produced. Conveniently the hydrogen gas is vented more or less at the rate generated from the reaction zone, and most of the aluminate may be removed in the water of the leaching composition, if desired. It is preferred to conduct the activation operation under inert conditions, such as under a blanket of nitrogen gas or a gas of the helium family, primarily to avoid forming explosive mixtures of hydrogen and oxygen.
At the end of a contacting operation by the teachings of this invention, the resulting solid catalyst particles remaining are preferably washed with water preferably to a neutral pH (e.g. a pH in the range offrom about 7.0 to 7.5). The product catalyst is then removed from the reaction zone, and wet screened to separate fines, preferably.
The product catalyst is conveniently stored under water, as in drums, prior to charging to a reactor for use in the practice of the process of the present invention. Keeping the catalyst under water prevents oxidation by air which occurs rapidly if the catalyst is allowed to have oxygen ex-' posure.
The hydrolysis reaction of this invention proceeds even when the amount of the catalyst prepared as described herein is very slight. For example, addition of such catalyst in an amount of 0.01 gram per mol of acrylo- -,,',~,', , ~ . . ~ . - . ~ , nitrile is sufficient to make the reaction proceed. The greater the amount of catalyst used, the faster the reaction proceeds, in general, thus permit-ting an increase in the amount of acrylamide produced. Consequently, the amount of catalyst employed per mol of acrylonitrile initially employed can preferably range from about 0.01 to 100 grams, although more catalyst can be used, if desired.
Acrylamide may be made from the mixture of acrylonitrile and water in accordance with the present invention using a suspension bed or a fixed - bed of catalyst. Combinations thereof may be employed. Two or more reactors may be connected in series and the reaction liquid and the catalyst, as when a suspension bed system is employed, may be counter-currently moved to effect and enhance reaction.
The hydrolysis process of this invention may be practiced under atmospheric pressures, which are preferred, but the process may also be -practiced at superatmospheric and subatmospheric pressures. Batch processing may be used, but continuous is preferred.
When practicing the process of the present invention using such a Raney copper catalyst prepared as described herein and utilizing a suspension bed system, it is preferred to employ the Raney copper catalyst in the form of particles at least 90 weight percent of which are in an average size range from about .002 to 0.100 inch. Similarly, when the present invention is practiced using such a Raney copper catalyst in the form of a fixed bed system, is it convenient and preferred to use the Raney copper catalyst in the form of particles at least 90 weight percent of which range in average size from about 0.02 to 0.50 inch.
In one more preferred catalyst preparation procedure, using the preferred route above described, the said group of alloy particles is confined to a reaction zone. A caustic solution and a solution of hydroxylated hydro-carbon compound may be admixed and con*acted with said group of particles in - 30 said zone, but the resulting aqueous medium is gradually removed from said zone during the contacting. In another more preferred catalyst preparation procedure, using the preferred route above described, the said resulting - 11 - .
,-, -, : ~, ,, . ~ . . . - . . - - . - - . . - - .

aqueous medium is so removed at a volumetric rate which is about equal to the rate of addition of said caustic solution. In such a removal procedure, substantially 100 weight percent of this so removed resulting aqueous medium can be recycled back into contact with the group of particles being activated.
During such a recycle, the so recycled aqueous medium is admixed with at least a portion of fresh caustic solution before or during recycle contact with such a group of particles.
Alternatively, less than 100 weight percent of said so removed resulting aqueous medium can be recycled back into contact with said group ~
of particles. The balance up to 100 weight percent thereof is permanently -removed from said reaction zone and can be discarded. Caustic may be added to such reaction zone at a rate approximately equal to the rate at which caustic is consumed through reaction with the aluminum in the alloy. The contacting process involving caustic addition may preferably be practiced continuously at a rate which is approximately equal to the rate of caustic consumption.
The amount of aluminum left in the catalyst after an activation, as described ,.
herein, can vary widely, but in the case of an active catalyst used for fixed bed catalysis, it has been found that as much as 20 weight percent aluminum (based on total catalyst weight) can be present in a catalyst without apparent-ly affecting catalyst use and performance characteristics, such as conversion rate, throughput rate of reactance, catalyst life) catalyst activity etc. a fact which is somewhat surprising in view of the prior art above reviewed.
In preparing a catalyst for use in this invention, it will be appreciated that there apparently is a sensitive relationship between the temperature of activation and the time of caustic contact with starting alloy.
In general, the higher the temperature, the longer should be the time for caustic addition to provide an active catalyst, because under such conditions ,; :. .
; localized overheating of the catalyst particles is avoided or reduced to a minimum level. Localized overheating of alloy particles may interfere with generation of a catalyst having an optimum desired group of characteristics ~ -associated therewith for use in the hydrolysis reaction constituting the process of the present invention. If one employs a rapid reaction between ~:

alloy particles and alkali, there tends to be produced a lessening of catalyst activity. A surprising amount of heat is liberated when one contacts alloy particles with caustic so that, on a large scale of catalyst activation, refrigeration equipment could be used to remove the exotherm.
As used herein the term "gradual" includes not only continuous but also intermittent addition of alkali to alloy particles or removal of a resulting aqueous medium from the zone of a given activation reaction.
Even after a great portion of removable aluminum in particles has -been etched away by caustic, as in a conventional Raney copper catalyst activation procedure, one can still obtain a benefit (improved catalyst activity in the hydrolysis process of this invention) by contacting such par-ticles with a solution of alkali metal hydroxide and hydroxylated hydrocarbon compound in accord with the teachings of this invention. Hence, a starting alloy material in particulate form for purposes of this invention can be one which has previously undergone a contacting with alkali metal hydroxide using, for example, prior art Raney copper catalyst activation technology. The beneficial results achieved by a contacting conducted in accord with this invention are characteristically producible even when using an aqueous treat-ing or contacting medium wherein the concentration of alkali metal hydroxide, and of hydroxylated hydrocarbon compound, respectively, is very low. Though as those skilled in the art will appreciate one can employ, as taught herein - relatively high such concentrations, low such concentrations are preferred, during a contacting operation as taught hereinO Mixtures of different ones of the additives taught herein may sometimes be advantageously employed during i contacting.
Referring to Figures 1 through 4, there are seen four equipment configurations, each one of which can be used to treat a group of starting alloy particles with aqueous hydroxylated hydrocarbon and with aqueous alkali i metal hydroxide to produce a desired activated Raney copper catalyst for use in the present invention. Thus, in Figure 1 there is seen an equipment con-i figuration where a group of particles 9 are confined to a reaction zone 10 ` and a caustic solution is added into the zone 10. The liquid added into zone : . . . , - . . - . .

10 through pipe 11 is allowed to accumulate in the zone 10. At the end of the - caustic addition, in accordance with the preferred catalyst activation pro-cedure of the present invention, and aftercaustic addition is terminated, the resulting treated particles 9 are removed from zone 10 as taught above. The particles 9 may be either initially wet with water or substantially free from water before alkali metal hydroxide addition is commenced. In one preferred - mode, the particles 9 are immersed in water.
In Figure 2 is shown a system similar to Figure l; corresponding parts thereof are similarly numbered, but with the addition of prime marks thereto. The system of Figure 2 is equipped with a drawing arrangement 12 which permits one to remove gradually from the vicinity of the group of par-ticles 9' the medium which results after the alkali metal hydroxide solutation and the hydroxylated hydrocarbon have each been brought into contact with the group of particles 9'. Preferably, the resulting aqueous medium is so re- -moved at a volumetric rate which is about equal to the rate of addition of the starting alkali metal hydroxide solutation and aqueous hydroxylated -~ hydrocarbon. -In Figure 3 is shown another system in which the parts similar to those of Figure 1 are similarly numbered bu* with the addition of double prime ~;
,3 20 marks thereto. Here, alkali metal hydroxide solution and the hydroxylated hytrocarbon are each gradually added into reaction zone 10" through a conduit 13. After the alkali metal hydroxide solution from conduit 13 has contacted the group of particles 9", the resulting aqueous medium is gradually removed , .
through a conduit 14. In conduit 14 this resulting aqueous medium is conveyed to a connection region 15 where conduit 14 is interconnected with a conduit j 16. Fresh alkali metal hydroxide solution and fresh hydroxylated hydrocarbon ~ are each conveyed through conduit 16 and is mixed with the aqueous medium in I conduit 14 in the region of connection 15 so that a mixture of the aqueous ~ metium and fresh alkali metal hydroxide solution and fresh hydroxylated hydro-`~ 30 carbon results, which mixture is then conveyed through conduit 13 back into the reaction zone 10", as shown. Such a system as shown in Pigure 3 permits economical use of alkali metal hydroxide, as those skilled in the art will .
' appreciate.
In Figure 4 is shown another system in which the parts similar to those of Figure 1 are similarly numbered but with the addition of triple prime marks thereto. Here alkali metal hydroxide solution and hydroxylated hydrocarbon are gradually added into the reaction zone 10"' through a conduit 13'. After the alkali metal hydroxide solution and hydroxylated hydrocarbon from conduit 13' has contacted the group of particles 9 "', the resulting aqueous medium is gradually removed through a conduit 14'. In conduit 14', this resulting aqueous medium is conveyed to a connection 17. At connection 17 a portion of the resulting medium is removed through a conduit 18, ~ffluent from conduit 18 may be discarded or otherwise disposed safely if desired. The -term portion here has reference to any fraction of the resulting medium rang-ing from greater than 0 to less than 100 weight percent or volume percent thereof. That portion of the resulting medium which is not removed from conduit 18 is conveyed by conduit 19 to connection region 15', where conduit 19 is connected with a conduit 16'. Fresh alkali metal hydroxide solution and fresh hydroxylated hydrocarbon are conveyed through conduit 16' and is mixed with the aqueous medium in conduit 19 in the region of connection 15' so that a mixture of the aqueous medium and fresh alkali metal hydroxide solution results, which mixture is then conveyed through conduit 13' back into the reaction zone 10"', as shown. Such a system as shown in Pigure 4 permits economical use of alkali metal hydroxide and in addition permits one selective-ly to remove spent alkali metal hydroxide and accumulated aluminate salts from the system during catalyst activation, as those skilled in the art will appreciate.
In each of the systems of Figures 2, 3, and 4, the group of par-ticles 9', 9 " , or 9 " ', respectively, may be either initially wet with water or substantially free from water, and in one preferred mode such respective groups of particles 9', 9 ", or 9 "', is immersed in water initially. As those skilled in the art will appreciate the representations in Figures 1 through 4 are in no way to be considered as limiting the actual conduit arrange-ment, method of alkali metal hydroxide addition or resulting medium removal, , ::

equipment orientation, or the like. Thus, for example, while for simplicity, gravitational type systems are shown in Figures 1 through 4, a system based on horizontal flow or vertical flow can be employed if desired, or some com-bination of flow directions of fluid over alloy particles during catalyst activation. In these Figures 1 through 4, those skilled in the art will readily appreciate that vent means for hydrogen evolved during activation is conveniently provided. Also, those skilled in the art will readily appreciate that actual plant equipment may involve more than one unit for a given zone indicated in Figures 1 through 4.
EMBODIMENTS
The present invention is further illustrated by reference to the following Examples. Those skilled in the art will appreciate that other and further embodiments are obvious and within the spirit and scope of this inven-; tion from the teachings of these present Examples taken with the accompanying specification.
- Example 1 - Activation of alloy to Raney coPPer catalyst . . .
'J A leaching reaction to activate a 50:50 weight ratio copper aluminum alloy is carried out using an apparatus arrangement as illustrated in Figure 1. The alloy, which is in the form of particles ranging in size from about 0.06 to 0.25 inch average diameter size, is placed in a wire basket which is rotated in a 1 to 3 liter reaction flask. The flask is provided with a nitrogen purge inlet, a buret for caustic addition, a thermometer and a hy-drogen outlet connected to a Wet Test Meter. Circulation of the leaching solution is accomplished by using a turbo-agitator in the flask beneath the basket.
After the alloy is placed in the basket mounted in the reactor flask, sufficient deionized water is added to the flask to completely immerse all particles and the agitator is set for about 120 rOp.m. Heating to a reaction temperature of 105~F is undertaken concurrently with a 30 minute nitrogen purge. Prior to the addition of the caustic solution an aqueous solution of gluconic acid, 50% by weight at ambient temperature, is added to . ~. ''. . , ' .

the water. The resulting aqueous solution of gluconic acid is estimated to contain from about 0.1 to 0.3 weight percent gluconic acid. The total amount of acid thus added is about 0.01 grams of acid per gram of alloy, on a dry basis.
, :
When the flask reaches 105F and the purge is completed, a 50 weight percent sodium hydroxide solution is added continuously over a 380 minute period to the system until 3 pounds of sodium hydroxide solution per pound of alloy have added, while controlling the temperature within + 2F with external cooling. -; 10 Contacting with the sodium hydroxide solution is continued until an ; -estimated amount of about 80 to 90 weight percent of the total aluminum present in the starting alloy has been leached, based on hydrogen evolution. The reaction rate is evaluated by monitoring the hydrogen evolution every 15 to 30 minutes. Thereafter, the product catalyst is immediately removed from the leaching solution and placed into a large excess of deionized water. The .
product catalyst is rinsed with deionized water until the pH of the rinse - water approaches 7.0 after which the product catalyst is stored under deionized -~ water to prevent oxidation thereof.
;~ Exa~ple 2 ~ 20 Activation of alloy to Raney copper catalyst i A leaching reaction using an apparatus arrangement as illustrated in ~ Pigure 2 to activate a 50:50 weight ratio copper aluminum alloy is performed : using a 1/2 inch outside diameter semi-batch fixed bed reactor. The reactor ~ is proYided with a nitrogen purge inlet, a buret for caustic addition, a ther-:j mometer, and a hydrogen outlet connected to a Wet Test Meter.
' At the bottom of the reactor a 3 to 4 inch bed of 4 mm glass beads -¦ are initially placed, and on top of this bed is positioned a charge of start- ;
ing alloy, which is in the form of particles ranging from about 0.06 to 0.25 ~i inch average diameter. A second bed of similar bead thickness is then placed i 30 on top of the alloy charge in the reactor. Then deionized water at ambient ': ~'.` .
- 17 - ~ ~
-"' ~. .

.

~ ~ 1042868 :
temperature is circulated through the bed while the reactor is being heated to 105~F. Immediately after heating is commenced, an aqueous solution of 50 weight percent gluconic acid at ambient temperature is added to the circulat-ing water solution at a level sufficient to produce a ratio of 0.001 grams gluconic acid per gram of alloy in the reactor; such addition is continued during this entire activation procedure during subsequent caustic solution ~ ~;
addition to the reactor.
Circulation of the leaching solution is accomplished by pumping a 1%
caustic solution Cdry basis) at a rate of 0.1 grams caustic per gram alloy per hour and allowing the resulting aqueous medium to be removed from the reactor at a rate approximating the pumping rate. A liquid level, sufficient to immerse the alloy and resulting catalyst, is maintained during the activation with a liquid leg device so that greater heat transfer capabilities may be obtained. ~ ---~ When the unit reaches 105F, the caustic solution, containing added gluconic acid in solution at a concentration estimated to be from 0.01 to 0.03 - .
weight percent, is added until a total charge of about 3 grams of caustic per gram of alloy has been contacted with the alloy. The circulation rate is thus about 10 grams resulting solution per gram of alloy particles per hour.
' 20 The reaction is continued until about 80 to 90 weight percent of the total amount of aluminum estimated to be present in the starting alloy has been ` leached, based on hydrogen evolution. The reaction rate is evaluated by moni-toring the hydrogen evolution every lS to 30 minutes.
The resulting product catalyst is then washed with deionized water -< until the pH of the wash water reaches the range of from about 7 to 7.5. The product catalyst is then retained under water to prevent oxidation. ~
~; Example 3 :
~ Activation of alloy to Raney copper catalyst -~ A leaching reaction using an apparatus arrangement as illustrated in Figure 3 to activate a 50:50 weight ratio copper aluminum alloy is performed , .. ' '', '.
: ' . ..:

' ~ ':.

104Z8~8 using a 1/2 inch outside diameter semi-batch fixed bed reactor. The reactor is provided with a nitrogen purge inlet, a buret for caustic addition, a ther-mometer, and a hydrogen outlet connected to a Wet Test Meter. Circulation of the leaching solution is accomplished by using a pump that is connected in a closed loop to the fixed bed reactor.
At the bottom of the reactor a 3 to 4 inch bed of 4 mm glass beads are placed on top of which is positioned a charge of starting alloy, which is in the form of particles ranging from about 0.06 to 0.25 inch average diameter.
- A second bed of similar bead thickness is placed on top of the alloy charge in the reactor. Thereafter, deionized water is circulated through the bed while the reactor is being heated to 105F. Thereafter an aqueous solution of 50 weight percent gluconic acid at ambient temperature is added to the water in a quantity to provide about 0.01 grams of gluconic acid per gram of alloy. The resulting aqueous gluconic acid concentration is estimated to be from 0.1 to 0.3 weight percent.
When the unit reaches 105F, a 50 weight percent sodium hydroxide solution is begun to be added at a rate of about 0.2 grams sodium hydroxide per gram of alloy per hour until a total charge of about 3.0 grams of such sodium hydroxide solution have been added per gram of alloy. Using a medium 2Q circulation rate similar to that employed in Example 2, the reaction is continued until about 80 to 90 weight percent of the total amount of aluminum estimated to be present in the starting alloy has been leached, based on hydrogen evolution. The reaction rate is evaluated by monitoring the hydro-gen evolution every 15 to 30 minutes.
The resulting product catalyst is then washed with deionized water until the pH of the wash water reaches the range of from about 7 to 7.5. The product catalyst is then retained under water to prevent oxidation.
Example 4 ~ -Activation of alloy to Raney copper catalyst A leaching reaction using an apparatus arrangement as illustrated in ~;

- 1 9 - , ~ .

~042868 Figure 4 to activate a 50:50 weight ratio copper al~minum alloy is performed using a 1/2 inch outside diameter semi-batch fixed bed reactor. The reactor is pro~ided with a nitrogen purge inlet, a buret for caustic addition, a thermometer, and a hydrogen outlet connected to a Wet Test Meter. Circulation of the leaching solution is accomplished by using a pu~p that is connected in a closed loop to the bed reactor.
At the bottom of the reactor a 3 to 4 inch bed of 4 mm glass beads are placed on top of which is positioned a charge of starting alloy, which is in the form of particles ranging from about 0.06 to 0.25 inch average diameter.
A second bed of similar bead thickness is placed on top of the alloy charge in the reactor. Thereafter deionized water at ambient temperature is cir-culated through the bed while the reactor is being heated to 105F. Immediate-ly after heating is commenced an aqueous solution of 50 weight percent gluco-nic acid solut on is added at ambient temperature to the water in a quantity to provide about 0.01 grams of gluconic acid per gram of alloy. The resulting aqueous gluconic acid concentration is estimated to be from 0.1 to 0.3 weight percent. When the unit reaches 105F, a 50 weight percent sodium hydroxide solution containing added gluconic acid in solution at a concentration esti-mated to be from 0.01 to 0.03 weight percent, is added at a rate of 0.2 grams of sodium hydroxide solution per gram of alloy per hour until a total charge of about 3.0 grams of such sodium hydroxide solution have been added per gram of alloy. A circulation rate similar to that of Example 2 is employed.
During such sodium hydroxide addition, a portion of the resulting aqueous ~ medium is removed from the system at a rate of 0.25 grams per hour per gram ; of alloy.
The reaction is continued until about 80 to 90 weight percent of the total amount of aluminum estimated to be present in the starting alloy has ~
. .
been leached, based on hydrogen evolution. The reaction rate is evaluated by monitoring the hydrogen evolution every 15 to 30 minutes.
The resulting product catalyst is then washed with deionized water ,' ,'''.'~ :'' - 20 - ~ --., -'.'- ' ~

until the pH of the wash water reaches the range of from about 7 to 7.5. The product catalyst is then retained under water to prevent oxidation.
Example 5 Hydrolysis Process The catalyst prepared according to the procedure of Example 1 is packed into a 12 inch continuous acrylonitrile hydrolysis reactor so as to form a fixed catalyst bed therein, the catalyst being covered with water during the charging operation to avoid oxidizing same. The reactor is sealed and pressure checked.
Water at the rate of 3.7 ml per minute and acrylonitrile at the rate of 1.5 ml per minute are charged to the reactor and the reactor tempera-ture is raised to 175F. When the reactor reaches 175~F and the flow rates are lined out, a one hour conditioning period is undertaken to insure that the system is equilibrated. A test is then started and a composite sample of the product stream is taken after 60 minutes followed by a second composite sample st the end of the next 30 minutes to check for possible variations.
', Thereafter the water feed rate is reset to 2,65 ml per minute and the , acrylonitrile feed rate is reset to 1.1 ml per minute. The unit is allowed to equilibrate for 30 minutes, and then a sample of the product is taken in the t 20 same manner as done previously. ~ -`
The samples are submitted to gas chromatographic analysis for de-terminatlon of water, acrylamide, and acrylonitrile content. Samples that are two phased are dissolved in methanol to yield a single phase sample for this analysis. The shut-down procedure requires cooling the reactor, terminat-ing the nitrile feed, and flushing the reactor with water to remove any resi-- dual nitrile.
The catalyst eYaluated in this procedure is compared with other catalysts produced using the process of example 1 with modifications as shown -in Table 1. Evaluation of the catalysts provided information relating the relative activity of catalysts to the process condition under which the cata-' ,' ' ;.' lyst is prepared. The aforementioned relative activity is based on the concept that under a specific set of reactor operating conditions, e.g., temperature, feed contact time, acrylonitrile concentration in the feedJ the same conversion level of acrylonitrile to acrylamide is obtained by varying the weight of catalyst present in the reaction zone. The ratio of the weight of catalyst required, to obtain the same conversion level of acrylonitrile to acrylamide as obtained with the catalyst assigned an activity of loO~ to the weight of catalyst having an activity of 1.0, is the reciprocal of the catalyst activityO
To illustrate, if the catalyst arbitrarily assigned an activity of 1.0 re-quires 50 grams of catalyst to obtain a conversion level of acrylonitrile to acrylamide of about 80% and a second catalyst requires 25 grams of catalyst to effect the same conversion of acrylonitrile to acrylamide of about 80%
then the reciprocal of the relative activity of the latter catalyst is 25 grams/50 grams = 0.5, and thus the relative activity is 1/0.5 = 200o Use of this analysis under the operating conditions described in this example provides the relative activity value of catalysts produced under various operating condi-J tions using the activation process of example lo The results are summarized si below in Table 1. The aforementioned relative activity is measured by the procedure described in Example 8 (parts a-n)O When each of the catalysts pre- `
pared by the teachings of Examples, 2, 3, and 4 is used in the hydrolysis ; reaction in the manner just described, similar results are obtainedO The in-formation contained in Table 1 demonstrates the vast difference in generating a catslyst as defined in this invention when compared to a catalyst activated by the method thereinabove referred to as the Kawaken methodO It is evident to those familiar with the art that the relative activity of a catalyst . . :
~` activated by the method claimed in this invention is significantly more .~.: ... ..
;~ active, i.e. by a factor of 4 to 7 times as active, as a catalyst prepared by the Kawaken method.
i Example 6 ;-; : ~ .
Hydrolysis process for testing catalyst life A system for hydrolyzing acrylonitrile to acrylamide is a reactor in , " ', - 22 - ~

.,.'. ;~,, ' ,, ' , ` ~, ' '., ' `; . :" ! ; ' " ' ' ' ' ' : ' . :

~LQ4Z868 the design of a double pipe heat exchanger with a flow system as indicated in Figure 2. The inner tube which constitutes the reaction zone which has a 5 foot length and is formed of 316 stainless steel and has 1" outside diameter schedule lOS pipe. The inner tube is uniformly surrounded by a jacket which is provided with an inlet at the bottom of the jacket and also with an outlet at the top of the jacket to allow circulation of a heat transfer medium to remove heat generated from the reaction. A temperature sensing device is ~ - , .

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~4Z868 FOOTNOTES FOR TABLE I
1. The catalysts (b), (c~, (d) and (e) are prepared according to the method taught in Example 1, except that the activation temperatures, per cent NaOH, NaOH addition time, and grams gluconic acid per 100 grams of alloy are varied as sum~arized in this Table.

~. :
2. Catalyst (a) is prepared by the method described by Kawaken Chemical Company, in which the alloy particles are incrementally added over a 1.5 hour period to an agitated solution to which all of the sodium hydroxide has been added prior to adding the alloy particles. After adding all alloy particles, the particles and sodium hydroxide are contacted for an additional 2 1/2 to 3 hours before removing the particles from the sodium hydroxide solution and washing them free of excess caustic.
3. In all cases, 2.5 to 3.0 grams of 50% sodium hydroxide solution ~
per gram of alloy are added to the reactor flask over the indicated NaOH addi- -tion time.
; 4. Percent NaOH is calculated as: W(0.5) where W is the weight of S ~ W :, 50% NaOH solution added to the reactor flask, and S is the weight of water initially present in the reactor flask just before starting the addition of the NaOH solution to the reaction flask.
; 20 5. Catalyst (b) is inferior to catalysts (c), (d) and (e) because of of the presence of the gluconic acid during catalyst activation in catalysts ~c), td), and ~e).

., .
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.
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. : -: ' :`' ,. ' ' ~ : ':
: 25 , '' ' '~. ' : .~ -:
;~ ~ . . .. .. ... .. . . . . .. .. . . . .... . . .. . . . . . .. . .

~04Z~68 installed in the inner pipe to allow temperature measurements throughout the reaction zone.
~uring operation of the reactor, acrylonitrile and water are sepa-- rately pumped from volumetrically calibrated feed tanks, combined, heated, and introduced into the bottom of the reactor. The reactor is maintained under pressure to allow maintaining liquid phase conditions. In this Example, the following process conditions apply to the operation in test of a catalyst pre- ~ -pared in the manner of Example 1, except that 0.053 grams of gluconic acid per gram of alloy are initially added to the water and approximately 4.1 grams of 50% NaOH solution are added per gram of alloy over a 5 hour period, and also except that the metal particles are not placed in a basket but are deposited on the bottom of the reaction vessel.
- Reactor temperature 220- 2F

Weight percent acrylonitrile in the feed 35 - 1%

Weight hourly space velocity 2.0 - 0.3 pounds of feed per pound of catalyst per hour. ;
As previously mentioned, the catalyst here used is a nominal 50% ~-copper, 50% aluminum alloy activated in the manner described in this invention.
A quantitative analysis of this catalyst after activation indicates that the activated catalyst composition is 81 weight percent copper and 19 weight per-, ' ..
cent aluminum. The catalyst, which is in the form of particles ranging in size from about .06 to .125 inches in diameter, is typical of other catalysts prepared as taught herein and evaluated in the process of this invention.
Product leaving the reactor is cooled before being reduced to at-- mospheric pressure. Such product is collected in a final receiver and . analyzed for acrylamide, acrylonitrile and water content. Based on these res-; pective analyses, conversion level of acrylamide, and activity of the catalyst at a particular point in time is determined by the method of Example 8 (a-h).
The initial activity of the catalyst is determined to be 1.2. ~fter about 500 hours of operation at the described test conditions, catalyst activi-- . . -:

` ` $~

ty remains at 1.2, within experimental error. After approximately 1700 hours of operation at the described test conditions, the catalyst activity is de-termined to be 0.8.
A typical catalyst prepared in the manner of this invention, has demonstrated remarkable life along with the previously mentioned high activity.
Using the hydrolysis test for determining catalyst life, a catalyst has been tested for more than 1700 continuous operating hours, during which period more than 1100 pounds of acrylamide per pound of catalyst were produced with an initial conversion level of acrylonitrile to acrylamide of about 80% and at the end of the test a final conversion level of acrylamide to acrylonitrile of about 70%.
The extremely long life of this catalyst and the small loss of cata-lyst activity over this period, demonstrates the superiority of this catalyst preparation method.
Example 7 ~parts a through i) A series of 8 different Raney copper catalysts are prepared using the following standardized procedure.
A three liter reaction flask is provided with a nitrogen purge inlet, a buret for caustic addition, a the~ometer, and a hydrogen outlet connected to a wet test meter. A basket is attached to a motor-driven agitator shaft so that the basket can be rotated inside the reaction flask during the activation procedure.
A total of 200 grams of a copper/aluminum alloy particles are placed inside of the basket. The particles are between 6 and 8 Tyler mesh in size, and they are approximately 50% aluminum and 50% copper on a weight percentage basis. A total of approximately 2650 grams of deionized water and a pre-selected amount of an organic additive are charged to the flask. The flask is subsequently closed and purged with nitrogen to prevent forming an explo~ive gas mixture during activation. A total of 662 grams of a 50% by weight solu-tion of sodium hydroxide in water are added to the flask incrementally over _ 27 -~Q9~Z868 ::
approximately a four hour period. After completing the sodium hydroxide addi--- tion, the mixture is held for an additional time period sufficient to allow a total of 4.2 to 4.7 cubic feet of hydrogen to evolve from the flask, as measured by the wet test meter. During the sodium hydroxide addition and the subsequent hold period the temperature of the liquid is maintained between 40 and 43C. The basket containing the metal particles is rotated inside the . liquid during the sodium hydroxide addition and subsequent hold period. After completing the activation procedure, the resulting Raney copper catalyst particles are washed repeatedly with water until the washings show a pH which is less than eight. Fines are removed by wet screening on a 10 Tyler mesh ;
: screen and subsequently are stored under water prior to testing for acryloni-trile hydration activity.
A total of 12 different organic additives are individually tested using the preceding procedure using 5 grams of the particular additive in each test. The addi~ives tested are (a~ gluconic acid; (b) lactic acid; ~c) malic acid; ~d) malonic acid; (e) tartaric acid; ~f~ glycolic acid. In addition, ; citric acid as additive (g) is also tested using 2.5 grams of it as additive, and glyceraldehyde as additive; Ch~ using 5.0 grams of it as additive. A
blank or control catalyst test (designated (i)) is run in which no additive is added to the catalyst preparation reaction vessel.
; Example 8 Cparts a through h) The 8 catalysts ~13 with additives) prepared in Example 7 are each '~ tested for acrylonitrile hydration activity by using the following standard-ized procedure:
A total of 80.6 grams of wet catalyst are charged to a reaction tube which has been fabricated from 3/4 inch diameter pipe. The reaction tube is immersed in a hot water bath which is used to control temperature inside the ' tube, as measured by thermocouples which are enclosed inside of a thermowell which projects into the reaction tube from one end.
When this reactor is used to determine activity Of a catalyst, acry-.~ . . ., ~ .. .:
.:

: ~ . -. . , - : . .. . - .- .. . . . i .

104Z~68 lonitrile and water are separately pumped from volumetrically calibrated feed tanks, combined, heated, and introduced into the bottom of the reactor. The reactor is maintained under pressure as necessary to allow maintaining liquid phase conditions. Product leaving the reactor is cooled before reducing pressure to atmospheric. Product is collected and analyzed by gas chromota-graphy for weight % acrylamide, acrylonitrile, and water. From this analysis the percent conversion of acrylonitrile to acrylamide is estimated.
For each catalyst, a series of different tests are run at different contact times with all other variables held constant, as follows:
1. Arithmetic mean catalyst bed temperature of approximately 175F.
2. Feed composition 100% basis of 25 weight % acrylonitrile and 75 weight % water.
Contact time is inversely measured as weight hourly space velocity CWHSV), which is defined as weight hourly feed rate divided by dry catalyst weight in the reaction zone.
The contact times are varied to bracket a 35% conversion of acryloni-trile to acrylamide. The WHSV required for a 35% conversion is estimated by graphical or statistical interpolation. The catalyst activity ~a) is then calculated from the following expression:
a a 6.3 CWHSY35) where WHSY35 is the weight hourly space velocity required for 35% conversion of acrylonitrile to acrylamide.
The activities determined by the preceding procedure for the catalysts prepared in Example 7 are tabulated in Table 2 and presented graphically in Figure 5. Pigure 5 shows that all additives having three or more carbon-oxygen groups per molecule impart improved activity to the Raney copper catalyst, while all additires having two carbon-oxygen groups per molecule did not make catalysts having greater actirity than the so called blank catalyst where no additive is used. Additives with a greater number of carbon-oxygen groups per molecule produce catalysts witll higher actirities. Glyceraldehyde however, is :
., ` "' "'~.

~;)42868 , a notable exception, in producing catalysts of which much higher activity than . other additives with only three carbon-oxygen bonds.

Additive Additive LevelCatalyst ~percent basedActivity on alloy charge) ~a) gluconic acid 2.5 6.2 (b) lactic acid 2.5 2.8 (c) malic acid 2.5 3,7 Cd) malonic acid 2.5 3.1 (e) tartaric acid 2.5 4.2 (f) glycolic acid 2.5 3.2 ~g) citric acid 1.25 4.3 ~hl, glyceraldehyde 5.0 7,4 Ci) blank-no additive ---- 3.2 . Exam~le-9 A catalyst first is prepared in the same manner as described in , Example 7 but, without adding any additive to the reaction flask prior to or ;, during the sodium hydroxide addition period.
Then this catalyst is treated as follows: A clean reaction flask as 2Q described and equipped in Example 7 is filled with approximately 2,650 grams of deionized water, 662 grams of a 50% squeous sodium hydroxide solution, and 10 grams of a 50% gluconic acid solution. The previously prepared Raney copper ~ catalyst is charged into the basket which is immersed into this resulting `~ solution and the basket is rotated in the solution for 3 1/3 hours. The liquid ten,~,perature is held between the 40 and 43C. Only 0.143 cubic feet of hydrogen ~ are invol~ed, as measured by a wet test meter.
i The catalys~t is subsequently tested for acrylonitrile hydration j actiYity by the method o Example 8. The catalyst is found to have an activity 3t of 4.9, which is about 5a% higher than the ion-additive treated catalyst of ~, 30 Example 8~n) which was prepared ~ithout any exposure to any additive with the ~ , .

-~30 - `

': , '- , ~

~09~Z~68 sodium hydroxideO
Example lO
A Raney copper catalyst is prepared using the apparatus of Figure 30 The preparation is conducted without the use of an additive to the activating sodium hydroxideO
- The system is charged with 10.5 pounds of 50% copper/ 50% aluminum alloy particles of 6 to 8 mesh particle size. Approximately 36 gallons of water are charged to this system, and a circulation rate of 105 gpm is begun through the particle bed and continues throughout the sodium hydroxide addi-; 10 tion step period. A total of about 31 pounds of a 50% aqueous sodium hydro-xide solution is subsequently added to the water at a substantially uniform ; rate over an 8 1/2 hour period. The circulation is continued until about 80 ' to 90 weight percent of the aluminum initial present is removed, as measured by hydrogen evolution. The catalyst is then first washed over wash water until ~ ..
- a pH of less than 8 is achieved, and subsequently is screened on a 10 mesh ~
;~ screenO : ' ' This catalyst is charged to the apparatus of Example 6, and is run for an extended period at the following test conditions:
Temperature 220F
WHSV 1.5 acrylonitrile to water weight ratio 35/65 Initial activity of the catalyst is determined by the procedure of Example 8 to be approximately 2~8. After about 500 hours of operation, the ~
activity is determined by the procedure of Example 8 to have declined to 1.30 --The catalyst of Example 6, which was prepared using gluconic acid, showed no decline in activity over a 500 hour test period when similarly evaluated, and in fact retained a higher percentage of its initial activity after over 1,700 hours of operation than the non additive treated catalyst of this example retained after only 500 hours of operation, thereby demonstrating .
that a more useful catalyst is obtained with the use of gluconic acid as an additive in the activation period.

.. .
' " "'

Claims (35)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Process for the preparation of a particulate Raney copper catalyst which comprises contacting particles of a metal alloy containing aluminum and copper in a weight ratio of from about 70:30 to about 30:70 together with adventitious impurities, with an aqueous solution which has dissolved therein on a 100 weight percent total by-product free solution basis from greater than 0 to about 25 weight percent alkali metal hydroxide and from about greater than 0 to about 25 weight percent, or the solubility limit thereof in water, whichever is lower, of at least one hydroxylated hydrocarbon compound of formula I

(R1)x(R2)y(R3)zA I

wherein:
(a) A represents a linear or branched alkyl group of three to eight carbon atoms;
(b) x + y + z is an integer of three to six inclusive;
(c) R1, R2 and R3 are hydrogen-oxygen functions sufficient to provide hydroxyl group, carbonyl group or carboxyl group functions in the alkyl group without increasing the number of carbon atoms present, or are groupings which hydrolyse under alkaline conditions to provide said hydroxyl carbonyl and carboxyl functions, provided that at least two of R1, R2 and R3 are such as to provide different functional groups in the alkyl group A, and that at least one of said groups is hydroxyl, said contacting being carried out at a temperature below about 80°C.

2. The process of claim 1 wherein said metal alloy is comprised of particles ranging in size from about 0.001 to 0.5 inch.

3. The process of claim 1 wherein said Raney copper catalyst is comprised of from about 2 to 45 weight percent aluminum with the balance up to 100 weight percent thereof being copper.

4. The process of claim 1 wherein the metal alloy contains aluminum and copper in a weight ratio of from 55:45 to 45:55.

5. The process of claim 1 wherein said solution comprises from greater than 0 to about 15 weight percent alkali metal hydroxide, from greater than 0 to about 5 weight percent hydroxylated hydrocarbon compound and with the balance up to 100 weight percent thereof being water.

6. The process of claim 1 wherein said solution comprises from greater than 0 to about 5 weight percent alkali metal hydroxide, from about 0.01 to about 1.0 weight percent hydroxylated hydrocarbon compound, and with the balance up to 100 weight percent thereof being water.

7. The process of claim 1 wherein at least about 25 weight percent of the initially present aluminum in said alloy particles is removed during said contacting.

8. The process of claim 1 wherein said contacting is conducted for a time ranging from about 1/2 to 30 hours.

9. The process of claim 1 wherein before said contacting with said solution said alloy is preliminarily contacted with a preliminary composition which comprises an aqueous solution of at least one hydroxylated hydrocarbon compound of formula I as defined in claim 1.

10. The process of claim 9 wherein said preliminary composition comprises from greater than 0 to about 25 weight percent hydroxylated hydro-carbon compound with the balance up to 100 weight percent on a total compo-sition basis being water.

11. The process of claim 9 wherein said preliminary composition comprises from greater than 0 to about 5 weight percent hydroxylated hydro-carbon compound with the balance up to 100 weight percent on a total compo-sition basis being water.

12. The process of claim 1 wherein said Raney copper catalyst is in the form of particles at least 90 weight percent of which range in average size from about 0.002 to 0.100 inch, which particles are suspended in the reactants.

13. The process of claim 1 wherein said Raney copper catalyst is in the form of particles at least 90 weight percent of which range in average size from about 0.02 to 0.5 inch which particles are in the form of a fixed bed over and through which the reactants are passed.

14. An improved process for making acrylamide from acrylonitrile comprising the steps of:
(A) activating a Raney copper catalyst through contact of aqueous alkali metal hydroxide with a metal alloy in particulate form and comprised of copper and aluminum in a weight ratio of from about 70:30 to 30:70 together with adventitious impurities, thereby to remove from such alloy particles at least about 25 weight percent of the aluminum initially present therein, at least a portion of such contacting being conducted over a time interval of from 1/2 to 30 hours using an aqueous alkali metal hydroxide solution which additionally has dissolved therein a compound of formula I

(R1)x(R2)y(R3)zA I

wherein:
(a) A represents a linear or branched alkyl group of three to eight carbon atoms;
(b) x + y + z is an integer of three to six inclusive;
(c) R1, R2 and R3 are hydrogen-oxygen functions sufficient to provide hydroxyl group, carbonyl group or carboxyl group functions in the alkyl group without increasing the number of carbon atoms present, or are groupings which hydrolyse under alkaline conditions to provide said hydroxyl carbonyl and carboxyl functions, provided that at least two of R1, R2 and R3 are such as to provide different functional groups in the alkyl group A, and that at least one of said groups is hydroxyl, said contacting being carried out at a temperature below about 80°C.
(B) contacting the so activated Raney copper catalyst with an aqueous comp-osition comprising from about 10 to 75 weight percent acrylonitrile with the remainder up to 100 weight percent thereof being water while maintaining a temperature of from about 60 to 150°C thereby to hydrolyse at least a portion of said acrylonitrile to acrylamide.

15. In a process for catalytically hydrolysing acrylonitrile to acrylamide by contacting acrylonitrile in the presence of water with a Raney copper catalyst, the improvement which comprises the steps of:
(A) first contacting an aqueous solution of a hydroxylated hydrocarbon com-pound with a group of metal alloy particles comprised of copper and aluminum, said hydroxylated hydrocarbon compound being a compound of formula I
(R1)x(R2)y(R3)zA I

wherein:
(a) A represents a linear or branched alkyl group of three to eight carbon atoms;
(b) x + y + z is an integer of three to six inclusive;
(c) R1, R2 and R3 are hydrogen-oxygen functions sufficient to provide hydroxyl group, carbonyl group or carboxyl group functions in the alkyl group without increasing the number of carbon atoms present, or are groupings which hydrolyse under alkaline conditions to provide said hydroxyl carbonyl and carboxyl functions, provided that at least two of R1, R2 and R3 are such as to provide different functional groups in the alkyl group A, and that at least one of said groups is hydroxyl, (1) said solution containing from about 0.01 to 1 weight percent of said hydroxylated hydrocarbon compound in dissolved form, (2) said group having an average particle size diameter in the range from about 0.001 to 0.5 inch, (3) said alloy having a copper to aluminum weight ratio of from about 30:70 to 70:30, together with adventitious impurities, (4) said solution having a temperature in the range from about 0 to 80°C, (B) secondly contacting the resulting said group of alloy particles with an aqueous caustic solution, (1) said aqueous caustic solution containing from greater than 0 to about 5 weight percent dissolved alkali metal hydroxide, (2) said contacting being accomplished over a total time interval of from about 1/2 to 30 hours, (3) said caustic solution being added gradually to said group over said time interval, (4) the contact rate of starting caustic solution being added to said group during such contacting being from about .01 to 10 pounds caustic per pound of said starting group of alloy particles per hour, (5) the total quantity of caustic so added being in the range of from about 0.5 to 25 pounds of caustic per pound of said starting group of particles, (6) said aqueous caustic solution and the resulting aqueous medium produced in such contacting each having a temperature in the range from about 0 to 80°C, (7) said group being maintained in said contact with said solution of said hydroxylated hydrocarbon compound during said contacting with said aqueous caustic solution by admixture of such respective solutions, (C) washing the so-treated group of product particles to separate therefrom remaining unreacted caustic, and (D) thirdly contacting at a temperature of from about 60 to 150°C the so-washed group of particles with an aqueous composition comprising from about 10 to 75 weight percent acrylonitrile with the remainder to 100 weight percent thereof being water.

16. The process of claim 14 wherein time interval of said second contacting ranges from about 4 to 12 hours.

17. The process of claim 15 wherein said group of particles is confined to a reaction zone and said caustic solution is added to said reaction zone and said resulting medium is allowed to accumulate in said zone.

18. The process of claim 17 wherein said group of particles is initially wet with water.

19. The process of claim 17 wherein said group of particles is initially substantially free from water.

20. The process of claim 18 wherein said group of particles is immersed in water.

21. The process of claim 14 wherein said group of particles is confined to a reaction zone, and said caustic solution is first contacted with said group of particles in said zone and said resulting medium is gradually removed from said zone.

22. The process of claim 21 wherein said resulting medium is so removed at a volumetric rate which is about equal to the rate of addition of said caustic solution.

23. The process of claim 21 wherein substantially 100 weight percent of said so removed, resulting medium is recycled back into contact with said group of particles.

24. The process of claim 23 wherein said so recycled medium is ad-mixed with at least a portion of said caustic solution before or during recycle contact with said group of particles.

25. The process of claim 21 wherein less than 100 weight percent of said so removed, resulting medium is recycled back into contact with said group of particles and the balance up to 100 weight percent thereof remains removed from said reaction zone.

26. The process of claim 1, 14 or 15 wherein said hydroxylated hydrocarbon compound is a polyhydroxylated aliphatic carboxylic acid.

27. The process of claim 1, 14 or 15 wherein said hydroxylated hydrocarbon compound is characterized by the formula:

R - (CHOH)n - COOH

wherein R is selected from the group consisting of CH3, CH2OH, COOH, CHO
and -H, and n is an integer of from 1 through 5.

28. Process according to claim 1, 14 or 15 wherein said Raney copper catalyst is treated with said alkali metal hydroxide under an inert atmosphere.

29. Process according to claim 1, 14 or 15 wherein said Raney copper catalyst is treated with said alkali metal hydroxide under a nitrogen atmosphere.

30. Process according to claim 1, 14 or 15 wherein said Raney copper catalyst is treated with sodium hydroxide.

31. Process according to claim 1, 14 or 15 wherein said Raney copper catalyst is treated with potassium hydroxide.

32. Process according to claim 1, 14 or 15 wherein said hydroxylated hydrocarbon compound is chosen from the group comprising gluconic acid, malic acid, tartaric acid, citric acid, and glyceraldehyde, or their ammonium or alkali metal salts or esters thereof.

33. The process of claim 1, 14 or 15 wherein said hydroxylated hydrocarbon compound is selected from the group consisting of gluconic acid, its alkali metal and ammonium salts, and esters thereof.

34. The process of claim 14 or 15 wherein said hydrolysis process is conducted using a starting composition containing from about 30 to 40 weight percent acrylonitrile with the remainder up to 100 weight percent thereof being water and at temperatures of from about 70 to 125°C.

35. The catalyst prepared by the process of claim 1.