US1691654A - Process of making thickened lubricating oil - Google Patents

Description

Patented Nov. 13, 1928.

UNITED STATES PATENT OFFICE.

ROBERT W. HENRY, OF PORT ARTHUR, TEXAS, AND ELFORD D. STREETER, OF BAY- ONNE, NEW JERSEY, ASSIGNORS TO GULF REFINING COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF TEXAS.

PROCESS OF MAKING THICKENED LUBRICATING OIL.

No Drawing. Application filed March 24, 1926, Serial No. 97,115. Renewed October 3, 1928.

This invention relates to processes of making thickened lubricating oil; and it comprises a method of producing an improved lubricating oil of the type sometimes known B as'mineral castor oil and consisting of lubricating oil containing a dissolved or dispersed basic aluminum oleate or other basic aluminum soap wherein a sodium soap solution is precipitated by a partially neutralized or basic solution of aluminum sulfate or other aluminum salt; all as more fully hereinafter set forth and as claimed.

In the art what are known as mineral castor oils or castor machine oils are extensively made by thickening mineral lubricating oils by an addition of a certain amount of aluminum oleate. This oleate is ordinarily a trioleate; that is, each atom of aluminum is combined with three oleic acid groups. These trioleate preparations are generally made by direct precipitation of a solution of sodium oleate by an aluminum sulfate solution in the proper proportions. The precipitated aluminum soap so made is separated from the mother liquor, which is a solution of sodium sulfate, Washed, dried and added to the mineral oil to be thickened. .The oleate goes into solution or dispersion and gives a great increase in viscosity; the result wanted. In the so usual types of mineral castor oil however this increase is neither regular nor constant. In adding a given quantity of oleate to a given oil, the exact increase in viscosity is uncertain and the viscosity just after incorporation is 25 by no means what it is after the thickened oil has been allowed to stand for a time and age. There is always a marked drop in viscosity. In United States Patent 1.550,608 is described a castor oil preparation free of the noted disadvantages; this preparation being made with basic oleates in lieu of the trioleate. Aluminum forms three oleates which may be represented, using thesymbol R to represent the oleic acid group, as respectively, the trioleate AlR the dioleate Al(OH)R and the mono-oleate'AN OH) B. In the stated patent it is pointed out that constant preparations may be obtained by the use of basic aluminum oleates; oleates containing less oleic to acid than the trioleate. The patent describes a ratio between R and A1 of 1.7: 1 or 1.8 1 as being most advantageous.

In the present invention mineral castor oils of this patented type are made but by the use using sodium oleate and aluminum sulfate in the proper proportions to make trioleate, precipitation of the aluminum sulfate solution is by a mixture of caustic soda and sodium oleate together. equivalent to the aluminum salt and in such relative pro ortions as to give a basic aluminum oleate o the type of.

that described in the patent. Caustic soda with aluminum sulfate solution gives a precipitate of aluminum hydrate, Al (OH) oleate gives aluminum trioleate, AlR,.; and a mixture of soda and oleate with aluminum sulfate solution gives intermediate products which are what is here wanted. Any desired ratio of R and OH may be thus obtained. Ordinarily we desire to obtain ratios within the limits prescribed in the stated patent. Our best results have been obtained with ratios between OH and R ranging between OH R and OH R' 'The foregoing describes the principle of the present invention but in practice the operation is somewhat more complex.

The sodium soap used in the resent invention may be made from any 0 the ordinary soap making oils and by any of the ordinary soap making processes. These oils all contain other fatty acids than oleic acid, but forpresent purposes as stated, these acids are more or lessequiv'alent to oleicacid. Cottonseed oil and corn oil are satisfactory oils for the present purpose. Commercial oleic acid or red oil, is less satisfactory because of its usual content of iron as an impurity. Rape oil may be used but is not as satisfactory as the other oils. Commercial stearic acid. oleo stearin and cocoanut oil do not give as good products as cottonseed oil. The particular oily materials used however are not as important as the chemical and physical control of the operation as hereinafter set forth. i

In a practical embodiment of the present invention a fatty oil is saponified with thecalculated quantity of caustic soda to produce a neutral soap;

this being done by any of the ordinary soap making processes.

There re- .sults a solution containing neutral soda salt' the caustic soda solution may be to Baum. Basic aluminum sulfate solutions are suitable for preparing aluminum soaps of the dioleate;

a composition approaching While basic aluminum chlorid solutlons are p more suitable for preparing the lower ratio soaps; 1. e. those whose compositions apadvantageous .to add some protective agent such as citric acid or a citrate, tartaric acid or a tartrate, etc. to prevent precipitation alumina.

of alumina. About 0.1 per cent of disodium citrate in the solution of the aluminum salt will sufiice to prevent precipitation of The neutral soda soap solution is emulsified with a body of lubricatin oil to form a pulp, the emulsion is heated to boiling,

'u'sual indicators.

the basic aluminum salt solution is added to it. To prepare a'soa'p of the composition LA 1.5,

to give the ratio 2AlCl :3NaOH, and the amount of this basic solution added to the soda soap solution is slightly in ,excess of enough to give the ratio 2A1c1, :smon emu.

This leaves the liquor slightly acid to the The amount of lubricating oil added may be from 1 to 2 times the volume soap. Within limits,

ofthe fatty oil originally used in making the the slower the addition of the aluminum salt solution the better.

' With a charge of ordinary size, it is recommended that the addition be spread over a lab period of about 2 hours. It makes a better preparation to continue boiling and stirring or about an hour after the addition of the aluminum salt, is completed. At this point,

the reaction'of the solution in contact withthe pulp should be slightly acid; P 4.5 is advantageous. lesides the solution of aluminum soap in 011, the batch at this stage contains a water solution of sodium sulfate which must be removed. This is accomplished by washingthe pulpy mass with boiling water for about 30 minutes, removing the water, and

digesting with a fresh. chargeof boiling water, a'nd so on, until theseparatedwat'er shows substantial freedom from sodium sulfate Three or four washings will. usually suflice. The washed material is then dried.

This may be accomplished by heating and stirring in an iron kettle. \Very careful contermined by In either case, it is the amount of caustic soda added to aluminum chlorid solution is enough rid) solution is added slowly.

trol of the drying operation produce the best products. Complete dehyration gives a yield of viscosity no higher than the mineral oil, while insufficient drying tends to cause a separation of the colloidal suspension wanted. Between these extremes lies the article desired; a very viscous preparation. This correct point is best dethe appearance of the material, and may be thus attained by one experienced in the art. Finally, the pulp is diluted by stirring in mineral lubricating oil until the viscosity of the desired commercial grade of caster machine" oil is attained.

Vhile we have described a method of mak ing a basic oleate wherein caustic soda is added to aluminum salt solution (the presence of a protective agent such as disodium citrate is necessary to solution and no protective agent is require V In this second embodiment of the present invention, a fatty oil is saponified with the calculated amount of caustic-soda by any of the ordinary soap makin processes. solution of this soap is emu sified with a body of lubricating oil and to this emulsion is added further caustic soda. The amount of mineral oil used in pulpingthe mixture may.

be 1 to 2 times the v0 ume of the fatty oil originally used. The amount of added al-.

kali is about enough to give a ratio of QNaR: NaOH. The alkaline mixture is heated toboiling and-aluminum sulfate (or chlo- The amount of alum added is'enougii to Al (SO :4NaR:2NaO e concentration of the alum solution may be 0.5 to 1 pound per gall The addition of alum solution should be spread over about ive the ratio 2 hours, and the boiling and stirring should be continued for about an .hour thereafter. After the addition, the reaction of the solution in contact with the pulp should be slightly acid; P 4.5 is advantageous.

The pulp is washed, dried and diluted with mineral oil as described above. By this method a di-soap caster is obtained;

,Potash soaps may be used in lieu of soda soaps; and potash 1B1 lieu of soda; but such substitution ofiers no particular advantage and adds to the cost,

The presence of lubricating oil during the manufacture of the basic aluminum oleates ing oil to give the Viscosity wa'nted.

WVhat Twe claim is 1. In the production of mineral castor oil of a constant viscosity and containing basic aluminum oleates,:the process which comprises preparing an aqueous solution of soap,

preparing a solution of an aluminum salt,

and intermixing the two solutions in the presence of alkali, thereby precipitating a asic aluminum soap, and admixing the aluminum soap with mineral oil.

2. In the production of mineral castor oil of constant viscosity and containing basic aluminum oleates, the process which comprises preparing an aqueous solution of soap, and adding a solution of an aluminum salt, invthe presence of alkali, thereby precipitating a basic aluminum soap, the amount of aluminum salt so added being suflicient to render the resulting liquor slightly acid.

.3. In theproduction of mineral castor oil of constant viscosity and containing basic aluminum oleates, the process whichv comprises preparin an aqueous' solution of soap,

preparing a so ution of an aluminum salt,

intermixing the two solutions in the presence acting materials being such as to effect the precipitation from the mixture of solutions of an aluminum-soap containing less fatty acid than that corresponding to a tri-acid soap, and to render the resulting liquor slightly acid.

4. In the manufacture of mineral castor oil of constant viscosity and containing basic. aluminum oleates, the process which comprises saponifying an oil with the necessary amount of alkali solution to give a neutral soap solution, emulsifying such solution with lubricating oil, precipitating a basic aluminum oleate b adding a solution of aluminum salt ma e basic by addition of alkali, washing the basic aluminum oleate with hot water to free it of salts, drying, and adding enough mineral oil to produce a mineral castor oil of the desired viscosity.

5. In the manufacture of mineral castor oil of constant viscosity and containing basic aluminum oleates, the process which comprises preparing an aqueous soap solution, and emulsifying lubricating oil therein; separately preparing a basic, aluminum salt solution by addin alkali to a solution'of an aluminum salt in t e presence of a protective agent, such as sodium citrate, in quantity sufficient to prevent the precipitation of alumi-- the dates indicated. of alkali added thereto, the quantities of re- Signed at Port Arthur, in the county of Jefferson and State of Texas, this 18th day