US2394608A - Dispersion - Google Patents

Description

F 94 I v. L. HANSLEY 2,394, 08

DISPERSIONS Filed NOV. 15, 1944 W519i? $.Hmmsiey INVENTOR.

Patented Feb. 12, i946 DISPERSION Virgil L. Hansley, Niagara Falls, N. Y., assignmto E. I. do Pontde Nemours & Company, Wilmington, Del, a corporation of Delaware Application November 15, 1944, Serial No. 563,617 Claims. (01. 252-309) This invention relates to the production of a dispersionof particles of metallic sodium in a liquid which is inert to metallic sodium. More particularly, it relates to the production of such a dispersion which is stable and in which there is a greatly reduced tendency of the sodium particles to settle or coalesce or unite with each other.

Dispersions of sodium in an inert liquid, for example, xylene, toluene, ether, petroleum, paraflin oil and the like, have been known and used for many years. These dispersions, or suspensions, are often referred to as sodium sand. In such previously known dispersions the individual sodium particles vary from 0.5 to 3 mm. in diameter and after vigorous shaking rapidly settle out of the liquid medium. Due to this settling, reagglomeration of the sodium particles often occurs. Due to the rapid settling rate of the sodium particles, the taking of aliquot parts of sodium by taking given parts of the liquid dispersion, is out of the question. It has, heretoe fore, also been. necessary to take great care in the preparation of sodium dispersions. A sodium sand dispersion is made at a'temperature above the melting point of the sodium and it has, heretofore, been necessary to allow the finely divided sodium to remain absolutely quiet during cooling through the melting point of the sodium. In such dispersions, the sodium particles, of course, settle out during the cooling thereof. The slightest agitation of such previously known dispersions during cooling causes the whole mass of sodium particles to coalesce or seize together.

It is an object of this invention to produce a dispersion of sodium in an inert liquid in which the particles of sodium will not settle at an objectionably rapid rate.

It is another object of this invention to produce'a dispersion of sodium in an inert liquid in which the particles of sodium will not readily seize or coalesce during cooling of the dispersion through the melting point of the sodium.

It isstill another object of this invention to provide a new and improved process for the preparation of dispersions of sodium in an inert liquid.

Other objects or the invention will appear hereinafter.

The objects i this invention are accomplished, in general, by preparing a dispersion comprising particles of metallic sodium, in an inert liquid having a boiling point above the melting point or sodium, and a small quantity of the sodium derivative of a higher fatty acid. Such a dispersion may be prepared by adding metallic sodium to a liquid which is inert to sodium and which has a boiling point above the melting point of sodium, the liquid being heated to a temperature between the melting point of sodium and the boiling point of the liquid. The inert liquid and molten sodium is agitated until the proper degree of subdivision of the sodium is obtained. Then, while the dispersion is still being agitated there is added a small amount of a higher fatty acid. The sodium dispersion or suspension can then be transferred to containers and allowed to cool. The sodium suspension thus prepared is not sensitive to handling at or near the melting point of the sodium.

A convenient form of apparatus for use in preparing the sodium dispersions of the present invention is shownin the accompanying drawing.

In the drawing, reference numeral l designates a one liter pyrex glass 4-neck flask positioned in an oil bath 6. A circulatory conduit system 2 is passed through two of the necks of the flask and also to the inlet and outlet openings of a circulatory pump 3 driven by motor 4. A suitable pump for use in this connection is Model EF inch Viking pump, having a displacement of 1% gal. per minute at 1800 R. P. M. and shown in Catalogue No. 396 of The Viking Pump Co., Cedar Falls, Iowa. The sodium, inert liquid and fatty acid may be fed to the flask through neck 8; and a, thermometer 9 may be placed in the remaining flask neck. If desired, a nitrogen conduit 1 may be placed in one of the flask necks through which the circulatory conduit passes into the flask, as illustrated. The oil bath may be heated by means of an electric heater 5 The finished sodium dispersion may be .withdrawn from the flask I through neck 8 by means of a suction or syphonlng hose, not shown.

The following examples are given to illustrate a number of preferred methods for carrying out the process of the present invention and to illustrate a number of preferred sodium dispersions. It is to be understood, however, that the details of the examples are not to be taken as limiting the scope of the invention.

Example I 300 grams refined kerosene was charged into the one liter flask shown in the drawing and heated to C. Nitrogen was continuously passed through the 'reactionflask during the preparation of the dispersion. With the kerosene in circulation, 200 grams sodium, out under refined kerosene in pieces small enough to enter the charging port was added at such a rate that the temperature did not fall below 120 0. Circulation was continued for 10 minutes after all the sodium had been added. The resulting suspension was then poured into a container to cool.

The particles of sodium ranged from 5-180.

microns in diameter; the average particle size being about 100 microns. Thesodium particles settled immediately to a solid cake comprising a hard mass very difllcult to disperse.

This example illustrates the diificulties en- 'countered in forming a. dispersion of sodium particles in an inert liquid as practiced prior to the present invention.

Example II 200 grams of refined kerosene was placed in the one liter flask illustrated in the drawing, and was heated to 130 C. 200 grams sodium was added to the kerosene while the latter was being circulated by apparatus similar to that illustrated in the drawing. After the dispersion of sodium particles in kerosene was formed, 2.5 grams of oleic acid was added drop-wise over a period of 7 minutesto the mass while circulation was continued. After the addition of the oleic acid, cir- Example III Following the procedure as described in Example'II, 200 grams sodium was dispersed in 258 grams refined kerosene at 130170 C. After the dispersion was formed, 1.7% pure lauric acid was added and agitation continued for 10 minutes longer. Nitrogen was passed through the flask during preparation of the dispersion. The particle size of the sodium averaged 180 microns, and these sodium particles settled only to the extent of 3.7% in three days.

Example IV Again following the procedure of Example 11, 300 grams xylol, refined by refluxing over sodium for one hour and distilling, was charged into the flask and heated to 130 C. 200 grams sodium, out under refined xylol, was added while the xylol in the flask was being circulated. After the sodium had melted and become dispersed in the 10], 5 grams oleic acid was introduced dropwise at a temperature of 130 C. and the mass stirred five minutes longer before removing to cool. Nitrogen was passed through the flask during the formation of the dispersion. After three days the product of this example was quite fluid although somewhat gelatinous. The particles of sodium ranged in size between 3 and 250 microns, averaging about 120 microns in diameter. The particles of sodium did not noticeably settle in a period of three days.

Example V 174 grams of mineral seal oil (hydrocarbon oil fraction having boiling range just above kerosene), produced by twice refluxing for one hour at 200 C. in the presence of sodium and then distilling, was charged into, the flask shown in the drawing and heated to 130 C. 226 grams of sodium out under refined mineral seal oil 'was added to the liquid in the flask while the same was circulated in the manner shown in the drawing. After circulating the mass for 10 minutes,v 2 grams of oleic acid was introduced over a five minute period. Themass was circulated for 10 minutes more and was then removed to cool. During the preparation of the dispersion, nitrogen was passed through the flask. The particles of sodium in the dispersion ranged in size from 2-150 microns, averaging 50 microns in diameter. These sodium particles did not settle after three days standing.

Example VI 160 grams Nuiol (a high boiling petroleum distillate purified by fuming sulfuric acid), refined over sodium, was placed in the flask shownin the drawing and heated to 130 C. 240 grams of sodium out under refined Nujol, was added to the flask while the Nujol in the flask was being circulated. After V the sodium had been added, 0.4 gram oleic acid was added to the mass. After circulating the mass for 15 minutes, at" a temperature of 140. C., 1.6 gramsof oleic acid was added over a five minute period. Circulation of the mass was continued for 20 minutes, the temperature gradually rising to 150 C., before removing this preparation. to cool. During the formation of the dispersion nitrogen was pmsed through the flask; The particles ranged in size from 2-180 microns, averaging about 60 microns in diameter. After three days standing there was no noticeable settling of the sodium particles. The mass flowed easily but was of a syrupy character.

ExampleVII 300 gramsof Nujol was heated to C. in a flask such as illustrated in the drawing, and 200 grams of sodium, out under Nujol was added while maintaining the temperature at 130 C. After the sodium had been added, 0.5 gram stearic acid was added and the remainder of the sodium then added and the mass circulated for a period of 10 minutes. Another 4.5 grams of stearic acid was then added to the mass over a five minute period. The mass was then stirred for 12 minutes at C. before removing to cool. During the preparation of the dispersion nitrogen was passed through the flask. The resulting dispersion was quite fluid and after three days the sodium particles settled to a negligible extent; the depth of the clear liquid above the sodium particles being 2% of the total height of the suspension. The sodium particles in'the dispersion ranged between 2-180 microns in diameter, averaging about 75 microns in diameter.

Example VIII 300 grams decalin was passed intothe flask shown in the drawing. The decalin was previously refined by treatment over sodium at 200 C.

and then distilled. The flask containing the tion of the mass was continued for 15 minutes while the temperature rose to 142 C. After three days standing, the particles of sodium which ranged in size from 3-130 microns in diameter, averaging 60 microns in diameter, did not settle. The suspension was gelatinous but became quite fluid after a little shaking.

The results of the several examples have been tabulated below.

Table of results Particle size E i F1 win oh eteristi gamma (muons) ramp o g are in m3 77777 W 1878 Range Average 1 i Settled to a hard mass not 45 -180, 100

easily shaken. 2 Flows readily 3.7 5-270 120 3-.- Qliflw fluid, slightly gelat- 3. 7 3-510 180 E0118. 4 qi iite fluid though gelat- 0 3-250 120 110118. 5 Solid cake, lumpy when 0 2-150 60 shaken. 6 Flows easily-oi syrup 0 2-180 60 meter. 7 gnite fluid 2 2-180 75 8 lows easily though go- 0 3-135 60 latinous.

1 Percent settled-(height of clear liquid above particle-i-total height)Xl00.

i No fatty acid.

The sodium dispersions of the present invention, as above illustrated, are prepared with the inert liquid having a temperature between the melting point of the sodium and the boiling point of the liquid. The preferred temperature range is 120 C. to 150 C. Below 120 C. the possibility of sodium freezing in the exposed pipe lines becomes greater; while above 150 C., the sodium derivative of the fatty acid is not as effective to prevent settling or seizing as at lower temperatures.

The amount of fatty acid added to the sodium dispersion is preferably between 0.1% and. 5%, based on the total weight of the dispersion, although smaller or larger amounts may be used. The amount of fatty acid used is only limited by the degree to which it is desired to reduce settling or seizing of sodium particles, and avoiding objectionably viscous dispersions. When using oleic acid as the fatty acid 0.5% by weight is considered to be optimum in a. sodium dispersion containing 60% by weight of sodium, and 1.0% oleic acid is optimum in a 40% sodium dispersion. These amounts are considered optimum since they are just enough to prevent any material settling of the sodium particles, and these amounts do not interfere with any desired circulation of the dispersions through pipe lines. The particular amount of fatty acid used is, of course, dependent upon the particular fatty acid used.

As inert liquid for the dispersion, any liquid which is inert to metallic sodium and which has a boiling point above the melting point of sodium may be used. If desired, a. second inert liquid which has a boiling point below the melting point of sodium may be added to the dispersion after cooling. such a. second inert liquid will function to largely prevent raising of the temperature of the dispersion above the melting point of sodium when the dispersion is used in carrying out certain exothermic reactions.

As higher fatty acids which may be added to the sodium dispersion to form the sodium derivative of a higher fatty acid, any of the commonly 75 known higher fatty acids, saturated or unsaturated, may be used. As examples of such higher fatty acids the following may be named: hexoic acid, diethyl acetic acid, heptoic acid, octoic acid, nonoic acid, capric acid, undecylic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, cerotic acid, melissic acid, oleic acid and erucic acid.

The sodium dispersions of the present invention may contain any desired amount of metallic sodium which is practical in the preparation of sodium dispersions. Usually, to be practical sodium dispersions contain between 20% and 65% sodium by weight. Above 65 there is difficulty in obtaining a satisfactory dispersion and below 20% the content of sodium is usually too low to be practical. Furthermore. below 20% a greater amount of fatty acid is needed to prevent settling or seizing of sodium particles.

Since it is obvious that many changes and modifications can be made in the above described details without departing from the spirit and scope of the invention, it is to be understood that the invention is not to be limited to said details except as set forth in the appended claims.

I claim:

1. A new composition of matter comprising a dispersion of particles of metallic sodium in an inert liquid having a boiling point above the melting point of sodium and containing a small amount, of the order of 0.1%-5%, of a higher fatty acid.

2. A new composition of matter comprising a dispersion of particles of metallic sodium in an inert hydrocarbon liquid having a boiling point inert hydrocarbon liquid having a boiling point above the melting point of sodium and containing between 0.1% and 5% of oleic acid.

4. A new composition of matter comprising a dispersion of particles of metallic sodium in an inert hydrocarbon liquid having a boiling point above the melting point of sodium and containing between 0.1% and 5% of lauric acid.

5. A new composition of matter comprising a dispersion of particles of metallic sodium in an inert hydrocarbon liquid having a boiling point above the melting point of sodium and containing between 0.1% and 5% of stearic acid.

6. A process for the production of a dispersion of sodium in an inert liquid which comprises melting sodium in an inert liquid having a boiling point above the melting point of sodium and agitating the mass to form a dispersion, adding, with agitation, a higher fatty acid to said mass, and cooling the dispersion to a temperature below the melting point of sodium.

7. A process for the production of a dispersion of sodium in an inert liquid which comprises melting sodium in an inert liquid having a boiling point above the melting point of sodium and agitating the mass to form a dispersion, adding, with agitation, between 0.1% and 5% of a higher fatty acid to said mass, and cooling the dispersion to a temperature below the melting point of sodium.

8. A process for the production of a dispersion of sodium in an inert liquid which comprises melting sodium in an inert liquid having a boiling point above the melting point of sodium and agitating the mass to form a dispersion, adding, with agitation, between 0.1% and 5% of oleic acid to said mass, and cooling the dispersion to a temperature below the melting point of sodium.

9. A process for theproduction of a, dispersion of sodium in an inert liquid which comprises melting sodium in an inert liquid having a boil ing point above the melting point of sodium and agitating the mass to form a dispersion, adding, with agitation, between 0.1% and 5% of lauric acid to said mass, and cooling the dispersion to a temperature below the melting sodium.

point of 10 10. A process for the production of a dispersion of sodium in an inert liquid which comprises melting sodium in an inert liquid having a boiling point above the melting point of sodium and agitating the mass to form a dispersion, adding, with agitation, between 0.1% and 5% of stearic acid to said mass, and cooling the dispersion to a temperature below the melting point of sodium.

VIRGIL L. HAN SLEY.

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