CA1096359A - Polymerization catalyst and method - Google Patents

Abstract

Abstract of the Disclosure A new catalyst and method of making polymers therewith and the process of preparing the catalyst in which the catalyst is prepared by dispersing on a finely divided carrier material, particularly a difficultly reducible inorganic support such as silica, an organic chromium (II) or (III) salt or derivative of a carboxylic acid or an N-substituted carboxylic acid or a nitrogen-hetcrocyclic carboxylic acid and activating the resulting mixture by heating at an elevated temperature in a non-oxidizing atmosphere.

Description

)963S9 POLYMERIZATION CATALYST AND METHOD

Summary of the Invention In accordance with this invention, l-olefins of 2 to 8 carbon atoms are polymerized or copolymerized with C2-C20 l-olefins to form solid polymers or copolymers in the presence of the catalyst of this invention which comprises essentially low-valent chromium surface species, as an active ingredient, dispersed and supported on at least one difficult to reduce inorganic oxide.
The new and improved catalysts and .methods of this invention are prepared by dispersing on a finely divided and difficult to reduce inorganic oxide selected from silica, alumina, thoria, zirconia, titania, magnesia and mixtures or composites thereof an organic chromium (II) or (III) salt or derivative of a carboxylic acid, an N-substituted carboxylic acid or a nitrogen-heterocyclic carboxylic acid to produce a mixture and then activating this mixture by heating to and at an elevated temperature up to about 2000F. and preferably at a temperature that is within the range of 850-2000CF. in a non-oxidizing atmosphere.
Accordingly the invention with broader aspects per-tains to a catalyst prepared by dispersing on a finely divided, difficultly reducible, inorganic support of the class consisting of silica, alumina, thoria, zirconia, titania, magnesia, and mixtures and composites thereof a chromium carboxylate contain-ing at least four carbon atoms in each carboxylate group and essentially of the formula of the class consisting of , 1~963S9 R-ll-O CrXn ¦ R'-fH-f-O- ¦ CrXn L R-NH 1 ~ m . _ R'-flI-CH2-C-O- CrXn and R-NE~ O m C-O ~ CrX

L I m n wherein R and R' are each selected from alkyl, alkenyl, aryl, cycloalkyl, cycloalkenyl and arylalkyl radicals and combinations of these radicals with each R containing 3-30 carbon atoms and each R' containing 0-20 carbon atoms and R' can be hydrogen and each R and R' containing a corresponding valence-satisfying number of hydrogen atoms, m is a whole number of 1 to 3, n is a whole number of 0 to 2 and m plus n is a whole number of 2 to 3, and X is a negative group relative to chromium, and activating the resulting mixture by heating to and at an elevated temperature of from about 600-2000F. in a non-oxidizing atmosphere.
The invention also comprehends the process of preparing the active polymerization catalyst and the method of makin~ polymers of l-olefins of 2 to 8 carbon atoms and copolymers of these olefins and l-olefins of 2 to 20 carbon atoms which comprises polymerizating the olefins under poly-merizing conditions with such a catalyst.

-2-~.

..

1~63~9 Description of the Preferred Embodiments In accordance with this invention polymerizable olefinic compounds and especially l-olefins of 2-8 carbon atoms are polymerized or copolymerized with C2-C20 l-olefins to form solid polymers and copolymers in the presence of the novel catalyst which consists essentially of low-valent chromium (chromium (II) or (III) or mixed) surface species as an active ingredient dispersed and supported or fixed on at least one difficult to reduce carrier material such as an inorganic oxide and particularly a support of the class consisting of silica, alumina, thoria, zirc~ia, titania, magnesia and mixtures or composites thereof.
The organic chromium salts or compounds suitable for this invention, from which the above-mentioned low-valent chromium surface species are derived, include the chromium salts or derivatives of a carboxylic acid, an N-substituted alpha- or beta- aminocarboxylic acid or a nitrogen-heterocyclic carboxylic acid which contains at least four carbon atoms in each carboxylate group and is of the formula:

~ -ICl- ~ CrXn O m ~'-TH-C-~ CrXn R-NH O m -2a-:; ~
., ~ ,, -1~96359 R'-CII-CH -C ~ CrX and l 2 Il ~ n r~ 0 cr~n wherein R and R' are each selected from alkyl, alkenyl, aryl, cycloalkyl, cycloalkenyl and arylalkyl radicals and combinations of these radicals with each R containing 3-30 carbon atoms and each R' containing 0-20 carbon atoms and R' can be hydrogen and each R and R' containing a corresponding valence-satisfying nun~er of hydrogen atoms, m is a whole number oE 1 to 3, n is a whole number of 0 to 2 and m plus n is a whole number of 2 to 3, a~
10 is a negative group relative to chromium. l'ypical chromium com-pounds of the above description are chromium pentanoate, chromium 2-ethylhexanoate, chromium benzoate, chromium oleate, chromium naphthenate, chromium derivative of N-phenylglycine, chromium derivative of picolinic acid, etc.

Catalyst Preparation In preparing a catalyst of this invention, one normally takes a series of steps as follows, some of them being optional as indicated.
Pretreatment of Support Catalyst support, selected from silica, alumina, zirconi~
thoria, magnesia, titania, or mixtures and composites thereof re-sulting from coprecipitation, impregnation, vapor-phase depositior etc., may have surEace area ranging from a few m /9 to over 700 m2/g but preferably above 150 m /g. Pore volume is preferably in excess of 0.5 cc,~g if surface area is primarily related to micropores. A finely divided non-porous support ~ith relatively high surface are~ such as CAB-O-SIL may also be used in this invention.
B

-3 ~9635~

Although not required, pretreatment of the support prior to its impregnation ~Jith an appropriate organic chromium compound is often preferred. Such pretreatment typically consists of ad-justing the moisture content of the support by drying at elevated temperatures or chemically modifying the support with compounds containing metallic elemen-ts such as zirconium, titanium, boron, vanadium, tin, molybdenum, magnesium, hafnium or the like. Chem-ical modification may include adding compounds such as ammonium hexafluorosilicate which can react with the support or with the 10 organic chromium compound during activation. Chemical modification using metal alkyls which react with the support can also be used.
The chemically modified support, especially wheninvolving the aqueous solution impregnation, is generally calcined at ele-vated temperatures to fix a modifier onto the support and also to expel an excess amount of moisture, much the same way as adjusting the moisture content in the unmodifiea support. The calcining or drying step is normally carried out at temperatures from 300 to 20000F. and can be done by any process known in the art such as in a muffle furnace or in a heated fluidized bed using gases such 20 as nitrogen, air, carbon monoxide or other suitable reactive or inert gases as fluidizing gases.

Dispersion of Chromium Carboxylate on the Support .. . . _ . _ _ .
The dispersion of a chromium carboxylate on the support can be readily accomplished by a conventional impregnation method using an organic solvent such as toluene or hexane. Equally satis-factory dispersion is often achieved by a more convenient method which calls for dry-blending of the carboxylate with the support and effecting the final dispersion during the initial stage of activation. If such a dry-blending technique is used, the subse-30 quent activation is best carried out in ~le fluid bed operation.

lG9~;359 The optimum chromium content of the catalyst is dependent on the support type, surface area and pore structure. With a typical support whose surface area is 100-800 m2/g and total pore volume is 0-3.0 cc/g, the chromium level may range from 0.05 to 10~ with the preferred level somewhere around 0.1-2.0 weight percent on the dry basis.

Thermal Activation of the Catalyst in Non-Oxidizing Atmosphere .
In accordance with this invention, the non-oxidizing lO atmosphere is provided either by inert gas such as nitrogen, he-lium, argon, etc., by reducing gas such as carbon monoxide, hydrogen, etc., or by evacuation to a sufficiently high vacuum.
In the last case, it is desirable to permit deliberate leak-in of a small amount of non-oxidizing gas. In all cases, a mixture of non-oxidizing gases may be used, if desired.
When the activation is carried out in non-oxidizing (inert or reducing) gas atmosphere, either fluid-bed or stationary-bed operation may be used. Experience shows, however, that fluid-bed operation is preferable. Normally, for economic reasonsr de-20 oxygenated nitrogen is used to fluidize the catalyst in an activator.It was experimentally established that even a minute conta~ination of oxygen during the activation generally has a detrimental effect on catalyst activity, and that such an adverse effect is greatly magnified when the chromium level is reduced to about 0.15% from a more typical 1 weight percent, often to the extent of completeiy deactivating the catalyst.
The activation step is usually carried out using a pre-selected heating cycle which includes heating the catalyst up to a specific temperature, usually in the range of 850-2000F.,hold-30ing the catalyst at this temperature for a prescribed length oftime, usually 30 minutes to 12 hours, fo~owed by cooling to ambient temperature in nitrogen atmosphere. The heating cycle may also ~i~96359 lnclude one or more hold periods at temperat~lres belo~ the l~lximum, as mentioned above, to permit diffusion of moisture, solvent, or gaseous products from the catalyst pores, or to permit reaetions such as decolllposition o~ the surface orgarlic chromi~lm speeies to take place. The final aetivation tcmperature is usually seleeted on the basis of several faetors such as desired resin properties, su2port type, pretreatment, etc. The heat-up rate a~ove G00F. is generally not critical.
The catalyst is preferably activated in a fluid bed using a non-oxidizing gas to maintain the mixture of support and chromium carboxylate under fluid condition while heating the mixture at about 300 - 350 F. for from about 1 to 3 hours and then at about 550 - 600 F. for about 1 to 3 hours to produce an interaction between the chromium compound and the support, followed by final activation at a temperature of about 850 -2000F. for a period of about 0.5 to 12 hours. The non-oxidizing gas may be nitrogen, hydrogen, carbon monoxide, noble gases and mixtures of these gases.

, .
Polvmerization Processes _ ___ __ __ _ The novel eatalysts of this invention may be used in liquid-phase, solution or slurry processes or vapor-phase proce~ses.
In the liquid-phase operation, any C3-C12 saturated hydroca~bon may be used as a reaetion medium or diluent. Other types of sol-vents, ineluding aromatie hydrocarbons and chlorinated solvents, ~ay also be used. The polymerization and copolymerizatioll of 1-olefins may be carried out in batch or continuous process. The eatalyst is generally charged into the reactor as a slurry in the eontinuous process, but as dry po~der in the batch process. The mode of charging the solvent and olefin to the reactor system may r~
, ~, ~963S9 follow any conventional practice applicable to batch or continuous operation, respectively. A vigorous agitation of the reaction medium is of course greatly preferred and so is the provision for efficient cooling to control the reactor temperature.
In liquid-phase proccsses, the olefin polymer or co-polymer is normally recovered hy flashing off solvent without any intervening steps for removal of the catalyst. The activity of the catalysts described in this invention is normally greater than 3000 poun~s of polymer per pound of catalyst so that catalyst removal is unnecessary for practicai purposes. Reactor conditions are dependent on the type of olefin as we~l as the desired polymer - 6a -- 1~963~

properties. In the case of ethylene, reactor pressures may range from 50 to 1000 psig, temperatures from 150F. to 500F. and solid levels from 5 to 60% by weight.
The following examples illustrate the invention.
Example 1 A catalyst was prepared by the following steps:
1. 37.0 grams of Davison 952 MS-ID silica gel, having about 350 m2/g surface area and 1.70 cc/g total pore volume, was impregnated with 110 ml hexane solution containing 6.0 grams solvent-free chromium naphthenate.
2. The hexane was evaporated off at 85-150F. by nitrogen sweep until the catalyst became free flowing. This dry-ing step always followed the impregnation using orqanic solvent and its mention will be omitted in the subsequent examples for simplicity.
3. About 15 grams of this impregnated and partially dried catalyst was charged into a catalyst activator consisting of a 38mm O.D., 27 inch VYCORTM glass tube, fitted with a fritted disc in the mid-section of the tube for the purpose of fluidizing the catalyst and provided with tubular electrical heaters around the tube for adjusting the catalyst temperature. The catalyst was then fluidized with a flow of deoxygenated nitrogen, approxi-mately 400 cc/min., and activated according to the following heating cycle: (a) held at 250F. for one hour, (b) held at 350F.
for one hour, (c) held at 550F. for one hour, (d) raised 200F.
every 15 minutes up to 950F., (e) held at 950F. for one hour, (f) raised 200F. every 15 minutes up to 1700F., (g) held at 1700F. for 2 hours, and (h) cooled down to ambient temperature in a nitrogen atmosphere. The deoxygenated nitrogen used in this and subsequent examples was obtained by passing high purity nitro-gen through a bed of reduced copper catalyst.

lOg63S9

4. The catalyst thus activated was transferred into a closed flask equipped with a hose-and-clamp at both openings without exposing it to air. This step was also applicable to all the subsequent examples and its mention shall be omitted here-after for sim~licity.
Evaluation of the activated catalyst for its ethylene polymerization activity was carried out in accordance with a general procedure as follows. The reactor, essentially an auto-clave 5" I.D. and about 12" deep, was equipped with an agitator rotating at 560 rpm, a flush bottom valve, and three ports for charging catalyst, isobutane and ethylene, respectively. The reactor temperature was controlled by a jacket containing methanol which was kept boiling by an electrical heater encircling the jacket. The control mechanism involved the automatic ad~ustment of jacket pressures in response to either cooling or heating re-quirements.
To test a catalyst, the reactor was first thoroughly purged with ethylene at temperatures around 200F., followed by the transfer of 0.05-0.5 g catalyst from a catalyst flask under nitrogen into the reactor via a transfer tube without exposing it to air. After the catalyst charge port was closed, 2900 ml iso-butane (dried and deoxygenated) was charged into the reactor, trapped ethylene was vented, and the reactor was allowed to warm up to 225F. The reactor was then pressurized with ethylene which was regulated at 550 psig and which was permittea to flow into the reactor whenever the reactor pressure dropped below 550 psig. An instantaneous flow rate of ethylene was monitored by rotameters of various capacity. The duration of a test run was normally from 40 minutes to four hours depending on the polymerization rate or desired productivity.
At the end of a test run, ethylene flow was cut of, the flush bottom valve was opened, and the reactor content was 1~)96359 dumped into a recovery pot, approximately 5" I.D. and 10" deep, where isobutane was allowed to flash off through a 200 mesh screen into the vent. Polymer par~icles le-Et in the pot were recovered and weighed.
In this particular case, the activated catalyst was tested twice. The firs-t run involved a catalyst charge of 0.1518 g, lasted for 60 minutes including an 8 minute induction period, and resulted in the recovery of 53 grams of polymer having the unmilled melt index of 0.4~. In the second run, the catalyst charge was 0.1562 g, run time was 60 minutes including 5 minutes of induction, the polymer recovered weighed 65 grams, and the polymer melt index was 0.43.

Examples 2-4 In contrast to the compositionally complicated chromium naphthenate used in Example 1, these examples illustrate the inven-tion with a simple chromium salt derived from a lower homolog of the monocyclic, saturated, monocarboxylic acids which are known to be the primary ingredients of co~mercially available naphthenic acids.
Chromium (III) cyclopentanecarboxylate used in these examples was prepared by the metathetical reaction between inter-mediate sodium cyclopentanecarboxylate and chromium trichloride in the aqueous medium Specifically, 12 grams of cyclopentane-carboxylic acid was first dissolved in a 100 ml aqueous solution containing 4.1 grams WaOH. After the pH was adjusted to about 9, this solution was mixed with 50 ml of an aqueous solution contain-ing 9.3 grams chromium trichloride, followed by heating and con-centrating the resulting mixture to obtain the precipitate. The precipitate was then dissolved in 250 ml toluene and washed in solution with 100 ml water for several times. The insolubles were then filtered off and the chromium compound recovered by evapor-ation.

1~963~ `

A catalyst was prepared by the following steps:
(1) About 10 pounds of Davison 952 MS-ID silica was dried in the pilot plant scale activator, essentially a 12" I.D.
by 30" long cylinder equipped with a gas dispersing plate and encircling electrical heater. The actual drying was accomplished in the fluid bed ~aintained by 100 SCFH of air and held at 1300F.
for five hours.
(2) 30.0 grams of this predried silica was then impreg-nated with 90 ml toluene solution containing 2.2 grams chromium cyclopentanecarboxylate obtained by the method described.
(3) The impregnated and partially dried catalyst was then activated in the VYCOR tube activator as in Example 1 except for the heating cycle, which consisted of: (a) hold at 250F. for one hour, (b) hold at 350F. for one hour, (c) hold at 550F. for one hour, (d) raise 200F. every 15 minutes up to 1600F., (e) hold at 1600F. for 2 hours and (f) cool down to ambient temperatures.
According to the general testing procedure described in Example 1, the activated catalyst was tested three times and the following results were obtained:

Run Polymer Exam. Catalyst Time Recovered Reactivity Resin MI
No. Charge,g Min. g. g/g/hr (unmilled) 2 0.1718 60 91 529 0.36 3 0.1614 70 105 554 0.32 4 0.1880 60 86 457 0.40 Example 5 This example is intended to demonstrate the applicability of the invention to unsaturated aliphatic carboxylates of chromium.
Chromium oleate, selected as a representative compound of this group, was assayed to contain 4.5% chromium.

~963S9 The catalyst was prepared by dispersing 8.~ grams of - this chromium oleate onto 35.5 grams of the predrie~ 952 MS-ID
silica of Example 2. The dispersing was accomplished by solution impregnation using 105 ml. hexane. About 12 grams of this impreg-nated and partially dried catalyst was then activated in the same manner as Example 1 except the final hold temperatur~ was 1600F.
instead of 1700F.
The catalyst thus prepared was tested in accordance with the general procedure described in ~xample 1. For ~he catalyst charge of 0.1641 gram and run time of 60 minutes including five minutes of induction there was recovered 70 grams o~ polymer corresponding to a reactivity of 426 g/g cat/hr.

Example 6 This example is intended to illustrate the chemical modification of the support prior to the dispersion of chromium carboxylate as well as to demonstrate the applicability of this invention to lower homologs of straight-chain carbo~ylates of chromium.
Chromium pentanoate used in this example ~as prepared 20 by the metathetical reaction between intermediate sodium pentan-oate and chromium trichloride in an aqueous medium. Specifically, 20 grams of valeric acid was first dissolved in 50 ml. aqueous solution containing 7.9 grams of sodium hydroxide. 17.4 grams of chromium trichloride dissolved in 50 ml. water was then added to the above solution followed by heating and evaporation of water to cause the precipitation of chromium pentanoate. After the mother liquor was removed, the precipitatc was dissolved in acetone and the insolubles were eliminated by filtering. A green thick semi-solid was obtained after the solvent was evaporated.
The catalyst was prepared by the following steps:

..

~63~9 (1) 400 grams of DAVISON 952 MS-ID silica was irpreg-nated with an aqueous solution prepared by disso]vincJ 9.65 grams zirconium tetrachloride in 1200 ml demineralized water, followed by dryin~ at 230F. in an oven equipped with mechanical convection until free flo.Ting. ~fter~7ard, the temperature was raised to 400F. and };ept thcre for ~ hours in the samQ oven.
(2) This zirconium tetracllloride-modifiecl silica was then calcined in a muffle furnacc by a heating cycle consistin~
of (a) hold at 400F. for one hour, (b) raising 90F. cvery 15 minutes up to 1200F., (c) hold at 1200F. for 4 hours, and (d) cool do~n to room temperature.
(3) 30.0 grams o~ th;s zirconium-modified silica was then imprecJncated with a 90 ml acetone solution containiny 2.1 gral~s of chro~ium pentanoatc obtained by the mcthod just dcscrib2d.
(4) About 15 grams of this imprcgnated and partially dried catalyst ~as activated by the method described in Example 2 except that the final hold temoerature was 1750F. instead of 1600F.
The activatcd catalyst ~7as evaluated in accordance with the general procedurc deseribed in Example 1. By charging 0.2~94 g eatalyst and terminating the run aftcr 60 minutes, 12~ grams o polymer was obtained showing a resin melt index oE 0.60 (on an un~illed scamplc).

F.xa~lcs 7-9 Thcse cxamplcs further illustrate a possible variation in preparinc3 the eatalyst of this invention. Erce acid in a small quantity is often found in a commercial chromium carboxylate sample, but n~ly also be added as a solvellt for a CJiVCII carboxylate, sor2times in excess of 50~ 70 grades of commercicll ehromium 2-ethylhexanoate reprcsented such a situation.

1096;~S9 In Example 7, a catalyst was prepared by impregnating 450 grams of the predried 952 MS-ID silica of Example 2 with a 1200 ml hexane solution containing 42 grams of chromium 2-ethyl-hexanoate which was analyzed to contain 10.8g6 chromium. About 15 grams of this impregnated and partially dried catalyst was then activated by the method of Example 2 except the final hold temperature was 1700F. instead of 1600F.
In Examples 8 and 9, a catalyst was prepared by impreg-nating 30.0 grams of the predried 952 MS-ID silica of Example 2 10 with a 90 ml hexane solution containing 2.8 grams of chromium 2-ethylhexanoate, the same material as used in Example 7, and 2.8 grarns of free 2-ethylhexanoic acid. The activation of the result-ing catalyst was exactly the same as in Example 7.
Test results of these catalysts, by the general method of Example 1, are summarized as follows:

Run Polymer Exam. Catalyst Time Recovered Reactivity Resin MI
NoCharge,g Min. g. g/g/hr tunmilled) -70.2010 60 64 318 0.47 80.1754 60 42 241 1.13 90.1608 60 58 361 1.99 Generally speaking, the presence of the free acid shows no significant effects on activity but may have some effects on the properties of the resulting polymer.

Exarrple 10 This example demonstrates the applicability of this invention to a chromium salt of aromatic carboxylic acid.
Chromium benzoate used in this example was prepared by the metathetical reaction between sodium benzoate and chromium 30 trichloride in the aqueous medium. Specifically,25 grams of sodium benzoate dissolved in 150 ml of water was mixed with 15.4 grams of 1~963S9 chromium trichloride in a 50 ml solution, followed by heating to precipitate a blue solid. After wash:ing with 500 ml watcr, the precipitate was dissolved in 300 ml d:ichloromethane for removal of insolubles. The filtrate was concentrated to ~orm a resin-like material which was readily ground to a blue powder.
A catalyst was prepared by first dissolving 2.4 grams of the above chromium benzoate in 90 ml dichloromethane. This solution was then used to impregnate 30.0 grams of the predried 952 MS-ID silica of Example 2. About 15 grams of this impregnated 10 and partially dried catalyst was activated by the same method as in Example 2. The catalyst thus activated was tested according to the general method described in Example 1. For a catalyst charge of 0.2067 g and a run time of 60 minutes, 11 grams of polymer were recovered.

Example 11 This example demonstrates the applicability of the inven-tion to chromium salts of N-substituted alpha-aminoacids, which is typified by N-phenylglycine (PhNHCH2COOH).
The chromium (III) derivative of N-phenylglycine used 20 in this example was prepared by heating a mixture of 3.2 grams of sodium hydroxide, 12 grams of N-phenylglycine and 7.0 grams of chromium trichloride in a 150 ml aqueous solution. The bluish-grey precipitate was washed with water and dissolved in 240 ml acetone for the removal of the insolubles. The partially purified chromium compound was recovered by evaporating the solution to dryness.
A catalyst was prepared by impregnating 30.0 grams of the predried 952 MS-ID silica of Example 2 with a 90 ml acetane solution containing 3.0 grams of the above chromium derivative of 30 N-phenylglycine. About 20 grams of this impregnated catalyst was activated essentially by the same method as in Example 2.

Tested twice according to the general method described in Example 1, the activated catalyst yielded the results as follows. For the catalyst charge of 0.1985 and 0.1963, 74 and 70 grams of polymer, respectively, were recovered each over a 60 minute run. Their reactivities were calculated to be 373 and 356 g/g/hr and their resin melt indices were 0.33 and 0.38, respectively.

Example 12 .. . _. _ This example further demonstrates the applicability of 10 the invention to a chromium derivative of nitrogen-heterocyclic carboxylic acids such as picolinic acid ~ OOH
The chromium derivative of picolinic acid used in this example was prepared as follows. A 100 ml aqueous solution con-taining 20 grams of picolinic acid and 6.5 grams of sodium hydroxide was added to 14.4 grams of chromium trichloride dissolved in 50 ml water. The red precipitate, formed on heating the solution, was washed with water, rinsed with acetone, and dried over mild heat.
1.3 grams of this ground chromium derivative of picolinic 20 acid was blended with 15.0 grams of the predried MS-ID silica of Example 2. The mixture was charged into the Vycor tube activator described in Example 1 and the activation of the catalyst was carried out in the same manner as in Example 2. Following the general test procedure described in Example 1, the catalyst was tested twice attaining reactivities of 587 and 534 g/g/hr, re-spectively.

Having described my inven-tion as related to the embodiments set out herein, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but 30 rather be construed broadly within its spirit and scope as set out in the appended claims.

..... ... .. . ..

Claims (40)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A catalyst prepared by dispersing on a finely divided, difficultly reducible, inorganic support of the class consisting of silica, alumina, thoria, zirconia, titania, mag-nesia, and mixtures and composites thereof a chromium carboxylate containing at least four carbon atoms in each carboxylate group and essentially of the formula of the class consisting of and wherein R and R' are each selected from alkyl, alkenyl, aryl, cycloalkyl, cycloalkenyl and arylalkyl radicals and combinations of these radicals with each R containing 3-30 carbon atoms and each R' containing 0-20 carbon atoms and R' can be hydrogen and each R and R' containing a corresponding valence-satisfying number of hydrogen atoms, m is a whole number of 1 to 3, n is a whole number of 0 to 2 and m plus n is a whole number of 2 to 3, and X

is a negative group relative to chromium, and activating the re-sulting mixture by heating to and at an elevated temperature of from about 600-2000°F. in a non-oxidizing atmosphere.

2. The catalyst of claim 1 wherein said chromium carboxylate is essentially of the formula

3. The catalyst of claim 1 wherein said chromium carboxylate is essentially of the formula

4. The catalyst of claim 1 wherein said chromium carboxylate is essentially of the formula

5. The catalyst of claim 1 wherein said chromium carboxylate is essentially of the formula

6. The catalyst of claim 1 wherein said chromium carboxylate is a member of the class consisting of chromium pentanoate, chromium 2-ethylhexanoate, chromium benzoate, chromium oleate, chromium naphthenate, chromium derivative of N-phenylglycine and chromium derivative of picolinic acid.

7. The catalyst of claim 1 wherein said support prior to the addition of said chromium carboxylate is pretreated by heating at a temperature of from about 300-2000°F. until volatile matter is at least partially driven off.

8. The catalyst of claim 1 wherein said chromium carboxylate is dissolved in a solvent and the resulting solution used to impregnate said support.

9. The catalyst of claim 1 wherein said dispersing of said chromium carboxylate is accomplished by dry blending with said finely divided support, followed by heating the mixture in a fluid bed maintained in suspension with a non-oxidizing gas flowing through said support during said heating.

10. The catalyst of claim 1 wherein said catalyst on a dry basis contains an amount of said chromium carboxylate to provide about 0.05-10 wt.% of chromium.

11. The catalyst of claim 1 wherein said activating is carried out in a fluid bed maintained by the flow of a non-oxidizing gas.

12. The method of making polymers of l-olefins of 2 to 8 carbon atoms and copolymers of said olefins and l-olefins of 2 to 20 carbon atoms which comprises polymerizing said olefins under polymerizing conditions with a catalyst prepared by dispersing on a finely divided, difficultly reducible, inorganic support of the group consisting of silica, alumina, thoria, zirconia, titania, magnesia, and mixtures thereof a chromium carboxylate containing at least four carbon atoms in each carboxylate group and essentially of the formula of the group consisting of and wherein R and R' are each selected from alkyl, alkenyl, aryl, cycloalkyl, cycloalkenyl and arylalkyl radicals and combinations of these radicals with each R containing 3-30 carbon atoms and each R' containing 0-20 carbon atoms and R' can be hydrogen and each R and R' containing a corresponding valence-satisfying number of hydrogen atoms, m is a whole number of 1 to 3, n is a whole number of 0 to 2 and m plus n is a whole number of 2 to 3, and X is a negative group relative to chromium, and activating the resulting mixture by heating to and at an elevated temperature of from about 600° - 2000° F. in a non-oxidizing atmosphere.

13. The method of Claim 12 wherein said chromium carboxylate is essentially of the formula

14. The method of Claim 12 wherein said chromium carboxylate is essentially of the formula

15. The method of Claim 12 wherein said chromium carboxylate is essentially of the formula

16. The method of Claim 12 wherein said chromium carboxylate is essentially of the formula

17. The method of 12 wherein said chromium carboxylate is a member of the group consisting of chromium pentanoate, chromium 2-ethylhexanoate, chromium benzoate, chromium oleate, chromium naphthenate, the chromic salt of N-phenylglycine and the chromic salt of picolinic acid.

18. The method of Claim 12 wherein said support prior to the addition of said chromium carboxylate is pretreated by heating at a temperature of from about 300 - 2000° F. until volatile matter is at least partially driven off.

19. The method of Claim 12 wherein said chromium carboxylate is dissolved in a solvent and the resulting solution used to impregnate said support.

20. The method of Claim 12 wherein said dispersing of said chromium carboxylate is accomplished by dry blending with said finely divided support, followed by heating the mixture in a fluid bed maintained in suspension with a non-oxidizing gas flowing through said support during said heating.

21. The method of Claim 12 wherein said catalyst on a dry basis contains an amount of said chromium carboxylate to provide about 0.05-10 wt. % of chromium.

22. The method of Claim 12 wherein said activating is carried out in a fluid bed maintained by the flow of a non-oxidizing gas.

- 20a -

23. The process of preparing an active polymerization catalyst comprising the steps of initially mixing with a finely divided, difficultly reducible, inorganic support of the class consisting of silica, alumina, thoria, zirconia, titania, mag-nesia, and mixtures and composites thereof a chromium carboxylate containing at least four carbon atoms in each carboxylate group and essentially of the formula of the class consisting of and wherein R and R' are each selected from alkyl, alkenyl, aryl, cycloalkyl, cycloalkenyl and arylalkyl radicals and combinations of these radicals with each R containing 3-30 carbon atoms and each R' containing 0-20 earbon atoms and R' can be hydrogen and each R and R' containing a corresponding valence-satisfying number of hydrogen atoms, m is a whole numher of 1 to 3, n is a whole number of 0 to 2 and m plus n is a whole number of 2 to 3, and X is a negative group relative to chromium, and activating the resulting mixture by heating to and at an elevated temperature of from about 600-2000°F. in a non-oxidizing atmosphere.

24. The process of claim 23 wherein said chromium carboxylate is essentially of the formula

25. The process of claim 23 wherein said chromium carboxylate is essentially of the formula

26. The process of claim 23 wherein said chromium carboxylate is essentiallY of the formula

27. The process of claim 23 wherein said chromium carboxylate is essentially of the formula

28. The process of claim 23 wherein said support prior to the addition of said chromium carboxylate is pretreated by heating at a temperature of from about 300-2000°F. until volatile matter is at least partially driven off.

29. The process of claim 23 wherein said chromium carboxylate is dissolved in a solvent and the resulting solution used to impregnate said support.

30. The process of claim 23 wherein said dispersing of said chromium carboxylate is accomplished by dry blending with said finely divided support followed by heating the mixture in a fluid bed maintained in suspension with a non-oxidizing gas flowing through said support during said heating.

31. The process of claim 23 wherein said catalyst on a dry basis contains an amount of said chromium carboxylate to provide about 0.05-10 wt.% of chromium.

32. The process of claim 23 wherein said chromium carboxylate is a member of the class consisting of chromium pentanoate, chromium 2-ethylhexanoate, chromium benzoate, chromium oleate, chromium naphthenate, chromium derivative of N-phenyl-glycine and chromium derivative of picolinic acid.

33. The process of claim 23 wherein said catalyst activation is carried out in a fluid bed maintained by the flow of a non-oxidizing gas.

34. The process of claim 23 wherein said catalyst activation is carried out in a stationary bed in a non-oxidizing atmosphere provided by evacuation of any gases from said bed.

35. The process of claim 23 wherein said catalyst activation is carried out in a stationary bed in a non-oxidizing atmosphere provided by a non-oxidizing gas.

36. The process of claim 33 wherein said non-oxidizing gas is selected from the class consisting of nitrogen, hydrogen, carbon monoxide, noble gases and mixtures of these gases.

37. The process of claim 23 wherein said catalyst activation is carried out in a fluid bed using a non-oxidizing gas to maintain the mixture of support and chromium carboxylate in suspension while heating said mixture to a final activation temperature of from 850-2000°F.

38. The process of claim 35 wherein said non-oxidizing gas is selected from the class consisting of nitrogen, hydrogen, carbon monoxide,noble gases and mixtures of these gases.

39. The process of claim 23 wherein said catalyst activation is carried out in a fluid bed using a non-oxidizing gas to maintain the mixture of support and chromium carboxylate in a fluid condition while heating said mixture at about 300-350°F. for from about 1 to 3 hours and then at about 550-600°F.
for about 1 to 3 hours to produce an interaction between the chromium compound and the support, followed by final activation at a temperature of about 850-2000°F., for a period of between about 0.5-12 hours.

40. The process of claim 39 wherein said non-oxidizing gas is selected from the class consisting of nitrogen, hydrogen, carbon monoxide, noble gases and mixtures of these gases.