US1918603A - Process of making soap and glycerine - Google Patents

Description

Patented July 18, 1933 UNITED STATES. PATENT OFFICE :IA RTIN HILL ITTNER, OF JERSEY CITY, NEW JERSEY, ASSIGNOR- '10 OOLGATE- PALMOLIVE-PEET COMPANY, 01 CHICAGO, 'ILLI NOIS, ATXJBPOBATION OI DEA WARE PROCESS OF MAKING 80A]? AND GL YCERINE No Drawing.

The invention relates to a new and useful process for the manufacture of soaps and glycerine.

In the saponification of soap stocks two val- 5 uable co-products, soap and glycerine, are obtained. Of these two co-products soap is the more important and for this reason the methods of saponification known prior to my invention have been designed primarily to yield good soap. All of the known rocesses involve an appreciable sacrifice in 0th the quality and quantity of glycerine produced. The importance of glycerine as a product has grown so that for some years past this sacrifice in the yield of glycerine has constituted an appreciable but apparently unavoidable waste.

The raw materials from which soaps and glycerine are prepared are:

1. Fats and/or fatty oils ,of animal and/or vegetable origin.

2. Basic or alkaline materials. 3. Additions of allsorts to the finished soap.

Fats and/or fatty oils contain substances known as glycerides. These are chemical combinations formed by the union of one molecule of glycerine with one or more molecules of fatty acid. A general structural formula for a typical glyceride is:

o H R iO- J-H R-rLo rz R-il-O- -H The structural formula for glycerine is:

H 5 rr-o--n n-o -H Fats and/or fatty oils also contain varying proportions of free fatty acids which can be speed up the reaction without employing ex- Application filed February is, 1931. s rial No. 511,090.

represented by the general structural formula:

R-Ji-O-H A glyceride molecule may be split so that with the proper distribution of the'hydrogen and oxygen atoms of three added molecules of water there will result three molecules of fatty acid and one molecule of glycerine as represented structurally below.

tageous. The progress of the reaction ma be speeded up by adding to the water a sma 1 amount of mineral acid, as sulphuric acid, or a small amount of base, as'lime, and by increasing the temperature of the reaction by carrying it out under pressure, as in the old autoclave processes. The process of aqueous saponification has also been hastened at ordinary pressures at the boiling point of water by the employment of special acid ca-talyzers, as in the welleknown Twitchell process. In the autoclave processes it is, impossible to employ very high temperatures .to

cessive and dangerous pressures and expen sive apparatus. All of these processes have the disadvantage of depending on balanced reactions which do not run to an end and do not effect complete splitting of the fat into fatty acid and glycerine. Fatty acids will combine readily with alkalies or the alkali of alkali carbonates to form soap in a manner akin to the usual interaction of acids and alkalies, or acids and 10 alkali carbonates. Caustic alkalies act on fats and glyeerides with the formation of soap and glycerine thus:

0 n n-ti-o-mo (on-t-H This reaction, known as saponification, is favored by heat, intimate contact and alkali concentration.

At temperatures up to the boiling point of water alkali carbonates exert only a slow sa onifying action on fats and glycerides.

ats and/or fatty oils generally contain small quantities of various saponifiable or unsaponifiable substances other than fatty acids and glycerides, which are very objectionable for soap-making purposes. These materials often cause extremely objectionable odors in the finished soap and exert an obj ectionable catalytic influence favoring the development of rancidity. Some of them also inhibit the lathering properties of the finished soap.

The most common method of soap-making now in use involves the saponific-ation of comparatively high grade fats and oils in open or loosely covered soappans or kettles with the aid of moderate steam heat and steam agitation at atmospheric pressure. During the process of saponification lycerine is formed. The mixture obtaine by the saponification referred to above comprises soap, water, glycerine, excess alkali and usually some unsaponified fat. Glycerine is soluble in water and to a very considerable extent in soap, especially in soap containing an appreciable amount of water. For the removal of soap and excess alkali and other impurities the mixture of soap, glycerine, etc.,

obtained by saponification is salted out by addition to the soap kettle of considerable quantities of common salt or strong solutions of common salt. Strong salt solutions have the property of throwing soap out of solution while dissolving glycerine and watersoluble impurities. The soap, glycerine, salt,

water ,niixture is boiled for some time and then allowed to settle. The glycerine, salt, water mixture containing some excess alkali, known as soap lye, separates and is saved for recovery of glycerine. The glycerine divldes up between the soap lye and thesoap,and although it is somewhat more soluble in the soap lye-than-in thesoap, a very considerable proportlon 1s, nevertheless, retained by the soap phase, which is usually much larger than the lye phase, so that a considerable number of successive lye treatments or washlngs are necessary for the removal of the greater portion of the glycerine. Dursary for the removal of excess alkali, soluble soaps and other impurities. It is also necessary to filter the llyes for removal of suspended lmpurities an to evaporate them for the removal of the large amount of water that is necessarily used in the washes for the extraction of glycerine. During the evaporation salt separates out before the glycerine becomes very concentrated and constitutes a troublesome impurity in the glycerine. Also, an appreciable loss of glycerine usually takes place in evaporation, due to overhead entrainment. :The crude glycerine finally obtained by evaporation of the large amount of water used in extracting the glycerine is filtered or otherwise'separated from the separated salt and is subjected toa series of distillations. The presence of salt in the crude glycerine and the accumulation of it in the still residue during the distillation of glycerine interfere to a considerable degree with the progress of the distillation and have an unfavorable effect on the quality of the distillate so that additional distillations are usually resorted to for further purificationv of the glycerine.

In every step of the soap and glycerinemaking process losses of glycerine are encountered. A very appreciable amount of glycerine remains unextracted in the soap without adding to the good qualities thereof, and further quantities are lost during the filtration of the lye, the removal of the salt, and in the still residues, while other portions are unavoidably lost by entrainment in evaporation and in further distillations.

The soap, after having been subjected to a number of boilings with excess alkali to insure complete saponification, and a number of washes for the further extraction of glycerine, is still contaminated with an appreciable excess of alkali and a considerable amount of salt and contains an appreciable amount of glycerine that is not recoverable. The soap is boiled with water and brought to a condition of flpidity that favors the separa-- tion of the soap mass into two layers, the upper of which is known as settled soap and contains about three-fourths to. fourfifths of the soap, and the other as nigre, which contains most of the salt and excess alkali still left in the soap pan and the greater portion of insoluble impurities. The disposal of the nigre by reprocessing is an additional burden in known soap-making processes. I

Another process somewhat in use is to sub- ]ect the fats and/or fatty oils to the so-called Twitchell process, which effects an acid saponification or hydrolysis of the fatty materials yielding fatty acids and glycerlne, the

glycerine formed in the reaction remaining dissolved in an aqueous acid layer and the fatty acids forming a. layer by themselves. This process does not effect complete hydrolysis in a single treatment but gives a balanced reaction in which the final roducts comprise fatty acids and glycerine formed by the hydrolysis and an appreciable amount of unhydrolyzed fat or fatty oil. In order to carry the hydrolysis or acid saponification more nearly to completion, further treatments are necessary, all involving time, expense and chemical treatment of the aqueous acid layer containing glycerine, and the subsequent evaporation thereof and distillation of the glycerine therefrom to render it fit for use. This process also leaves an appreciable amount of unrecovered glycerine unless the fats are subjected to several prolonged treatments, in which case a sensible darkening of the product occurs due to atmospheric oxidation and other causes. In common practise there is also an appreciable loss of glycerine in operating by this process. The fatty acids formed in the process are then commonly subjected to soap-making treatments substantially similar to those outlined above.

In any of the common soap-making processes. such as I have described above, the bulk of water involved in the extraction of the glycerine is many times the bulk of the glycerine produced. The cost of handling and evaporating this extremely large bulk of water is high. The process of my invention may be so operated that the glycerine is produced in concentrated form without any intermediate steps in which large quantities of water must be handled and evaporated, and substantially all the glycerine produced may be so recovered. This decided simplification in the recovery of glycerine is a novel and decidedly advantageous feature of my invention.

I have discovered that soaps made from fats and/or fatty oils when properly heated and kept from contact with oxidizing agents can be raised to temperatures ranging from under 300 degrees C. to 350 degrees (3., and even higher without pyrolysis or decomposition taking place. saponification of the fats and/or fatty oils subjected to the above process may take place prior to this process or during it. I have also discovered that glycerine resulting from the saponification of fats and /or fatty oils under the above named temperatures and proper conditions of agitation can be separated substantially completely as a vapor from the saponification mixture. I have also discovered that aqueous hydrolysis brought about by steam gitation at the comparatively high temper tures mentioned is quite rapid in the presence of basic media and that evenwhen there is an insufiicient amount of basic material present to convert all the fat and/or fatty oil into soap the hydrolysis will pro ceed comparatively rapidly with the formation of fatty acid and glycerine. I have further discovered in cases where I have employed a suflicient amount of basic materials to convert all fatty matter into soap that objectionable impurities often found in fats and/or fatty oils may be entirely removed from soaps made under the conditions of my invention. All of the above things I believe. were unknown and not in use prior to my invention.

In carr ing out my process I may employ a fat an /or fatty oil, as, for instance, tallow. This is'introduced into a closed vessel constructed preferably in the shape of a still and provided with means for heating. I heat the fat to its melting point and begin to blow through it a strong current of steam, which serves the purposes of effectively agitating the contents of the still, driving air from the still,-and guarding against the further entrance of any air. I prefer to heat the fat to a temperature well above the boiling point of water before introducing the alkaline or basic medium for saponification. I can employ a low temperature at the early stages of my process and subsequently increase the temperature, but prefer to introduce the alkaline or basic medium for fat saponification after first raising the temperature somewhat in excess of 200 degress C., preferably 250 degrees to 300 degrees C. At

these temperatures saponification takes place with extreme rapidity and the soap shows very little tendency to frothing or foaming, which may be observed and which may give some trouble at temperatures more nearly approximating the boiling point of Water.

In carrying out my process I may employ alkaline media or bases either in solution or in substantially anhydrous form or mixed with insufficient water for complete solution. These may be added separately or mixed with the fatty material. Water or hydrated bases are usually considered necessary to saponification for the formation of fatty acids and glycerine or soap and glycerine. Ordinarily, water in aqueous condition is employed for saponification. Under the conditions that maintain in my process a quantity of liquid water is not necessary as the saponification is brought about with ease by water in vapor form, as steam. Where alkaline media or bases in solution are employed the water of solution evaporates with great rapidity, in the form of steam. Where carbonates are leaving little or no water except that K employed carbon dioxide is evolved and the gas set free has an inert or protective action on the soap and/or fatty material, similar to steam.

The use of a strong current of steam to maintain-very thorou h mixing and to effectively revent loca overheating of any portion 0 the mass, and the maintenance of the temperature mentioned, comprise conditions very favorable to ra id saponification and to the volatilization o g1 cerine formed in the saponification. Under t ese conditions the ,soap mass or themixture of soap and fatty material have a very low vapor pressure and lycerine has a much higher vapor pressure.

lycerine vapors are swept from the still by the stron current of steam almost as fast as forme I prefer to continue the heating and agitation of the soap or the'mixture of fat and soap until a temperature of about 300 degrees to 325 degrees C. is reached, at all times using a sufficiently strong current of steam to maintain thorough agitation and effectively exclude air. I prefer to use an alkaline or basic soap-making material sufiicient to effect complete saponification or a slight excess over the amount necessary for complete saponification.

In the reaction carried out under these conditions glycerine, one of the products of the chemical reaction, is rapidly volatilized and, according to the well known chemical principle of mass action, the removal of glycerine in this way causes the saponification to run completely to an end, and the volatility of glycerine under the conditions stated permits of its complete removal from the reaction. In this reaction I may use caustic or carbonated alkalies, caustic or carbonated alkaline earths, nitrogen bases suitable for making soaps, or such other basic compounds of metals as may be necessary to produce metallic soaps where it is desirable to make this class of soap.

At a temperature approximating 300 degrees C. the soap mass is in a thin liquid condition and is perfectly stable where air is effectively excluded and local over-heating is prevente by the maintenance of suflicient agitation. The deleterious action of air and local over-heating may both be prevented by blowing a strong current of steam through the mass and carrying out the process in a still-like apparatus.

I may carry outmy process at atmospheric pressure or at diminished pressures and as a matter of experience find certain advantages in operating at diminished pressures, particularly for the volatilization of the last traces of glycerine from the liquid mass of melted soap. In any event, I may readily realize high temperature without the use of high pressures and so I prefer to operate when using non-volatile bases withoutresorting to super-atmospheric pressures. I condense the glycerine vapors and may condense much of the water vapor that passes over with the glycerine. These may be condensed together or almost completely separated from one another by fractional condensations,

owing to the reat difierence in boiling points of water an glycerine and great difference in vapor ressures of these materials at any of the di erent temperatures used. Glycerine may be condensed in any concentration up to or even exceeding 99 per cent. while permitting water vapor to remain in the vapor phase. The portion of my process consisting of fractional condensation of glycerine from water vapor is a part of common practice in glycerine distillation and need not be described in detail.

My process may be carried out as a batch process, treating a given amount of fat with approximately the definite amount of alkaline or basic material necessary to convert it into soap, or it may be carried out as a semicontinuous process by treating a certain amount of fat with the corresponding amount of alkali, distilling the glycerine therefrom, removing a portion of the soap thus formed, preferab y while still in a hot, liquid condition, and adding further quantities of fats and alkali in such a way as to maintain the mass at the preferably reacting temperature At this temperature the soap" are maintained, a temperature of 350 degrees C. may be employed or even exceeded for the reaction. On the other hand, the reaction described may be carried out at temperatures considerabl under 300 degrees 0., though it is preferab e that the temperature be sufiicientl high to maintain the substantially anhy rous soap in thin, 1i uid condition.

In my process I may uti ize any of the fats or fatty oils commonly employed for soapmaking purposes, but in addition to these or in place of them may use any of a great variety of fats or fatt oils which are oorly ada ted for soap-ma ing purposes by nown met ods because of one or another objectionties, and with a strong tendency to deteriorate rapidly with age.

I am aware of the fact that certain objectionable fish oils and whale oil are at times III subjected to hydrogenation in attempts to make them more suitable for soap-making purposes, but the process of hydrogenation is relatively expensive and is not readily applicable to low grade oils or materials with a high contentof free fatty acid, and soaps made from such hydrogenated fats possess extremely poor lathering and poor washing qualities if the hydrogenation is carried far enough to free the oils from objectionable odors and other qualities. they naturally possess.

Furthermore, all attempts heretofore to make good soap-making materials out of such low grade fish oils and the like as do not yield readily to hydrogenation, which have consisted in hydrolyzing them and subjecting the fatty acids therefrom to purification by distillation, have been unsuccessful for the reason that such acids yield soaps improved in color only by otherwise possessing all the repulsive odor and other objectionable qualities given to soaps made from such oils by direct saponification.

My process does not consist alone in the improved saponification and recovery of glycerine detailed above, but effects other desirable results. One of these isthe removal of certain undesirable unsaponifiable impurities by volatilizing them and removing them from the soap mass under conditions of the reaction. degree common to all fats and fatty oils. They are present in very minor quantities and in less objectionableform in the better grades of animal and vegetable oils, such as prime tallow and high grade cocoanut oil.

a They are present in greater quantities and in more objectionable form in various types of greases, such as house grease, extraction grease and garbage grease, and they are present in even greater quantities andin very objectionable form in most types of marine animal oils, imparting to these oils objectionable fishy odors, which become more pronounced after saponification of such oils, and which become even more pronounced on the aging of'soaps made from such oils. The conditious'which I have described above that maintain in'my process, and which are fa vorable to the volatilization of glycerine, are also effective in removing the above mentioned unsaponifiable impurities from soaps made from these oils by my process, thus resulting-in the production of a soap with a neutral or mild, agreeable odor. In the case of fish oils which are treated by my process, I succeed not only in removing objectionable volatile impurities possessed of a bad odor, but effect at the same time a rearrangement in the molecules of the soaps formed from some. of the more unsaturatel acids present in fish oils, so that the resulting soaps have properties more desirable than the soaps obtained from such oils by direct 'saponification,

These impurities are to a certain started with, there being no sensible decomposition or molecular breakdown or loss, such as is experienced in the Varrentrapp reaction or modifications of it, and there being no sensible polymerization to ether acids or bodies with a substantially higher molecular weight than those'started with. The fatty acidsobtained fromthe soap produced by my process commonly have a very slightly higher melting point than those obtained by direct saponification and acidification of the same material. This difference in melting point is seldom more than a fraction of-a degree and is brought about by the rearrangement of molecules of some of the unsaturated acids present. The iodine values of acids obtained from fatty material subjected to my treatment are usually somewhat less than the iodine value of acids obtained by direct saponification of the same fats or oils. This is also due to a rearrangement of the double bonds in the molecules of some of the unsaturated acids. Cases are known to the science in which a compound having the unsaturated bonds in one position, has a substantially higher iodine absorption than an isomeric body of the same molecular weight with the same amount of unsaturation having the unsaturated bonds in a different position. Fatty acids having unsaturated bonds so situated in amolecule as to be capable of the ready addition of large amounts of iodineare'wellknown to have a strong tendency to absorb oxygen, and soaps made from such acids have a. stronger tendency to become rancid. than soaps made from fatty acids that absorb lower amounts of iodine. The fact is that soap made by my process showslesstendency to alytically' to further oxidation and the for-.

mation of rancidity.

In cases where fats and/or-fat'ty oils are subjected to my treatment with an insufficient amount of alkali to effect complete saponification, the soap formed by thealkali which is used acts catalytically in the presence of the strong current ofsteam and high temperatures preferably employed, to effect comparatively rapid hydro ysis with the formation of glycerine and free fatty acids, both of which distil 'over and condense. The glycerine and distilled fatty acids under these circumstances condense substantially together but ma be separated from one another with cat acilit as the are almost mutually insoluble. 'l he disti led acids thus formed are capable of being made directl into soap. Ordinarily, I prefer to use a slig is excess of alkaline or basic medium over that necessary to effect complete saponification but do not limit -;nyself entirely to this amount. In some cases, even where a slight excess of alkali is usedover the amount required for saponification, failure to employ proper sequence or proportions in adding successive quantities of the reacting substances may result in distillation'of some fatty acids from the reacting mass. Such a practice constitutes no more than a diversion from the preferred manner of operating without departing from the general practice employed.

In some cases when operating on very impure, low grade fats, I may prefer to subjectthe fat or oil first to saponification and cleansing treatments by ordinar soap-making processes for the removal 0 certain impurities that may easily be removed in this way and which at the higher temperature ofmy reaction may break down and cause a darkening of the reacting mass. My process very commonly appreciably improves. the color of the soap obtained by it over the color obtained from the same material by ordinary soap-making processes. In cases where fats or'fatty oils are given a preliminary sa nification by old, well-known methods or the removal of such impurities as may be removed by present processes, the portion of in process consisting of heating soap under escribed conditions and blowing steam through it effects sensible improvements in the quality of soap so treated in odor, consistency, washing qualities and keeping qualities and in \color where readily decomposable impurities have been removed by such preliminary treatments. In the case of some fats and oils such readily decomposable impurities may be removed by a simple preliminary washing and settling with water or other simple known process for accomplishing a similar result.

During the part of my process in which I remove unsaponifiable, objectionable matter by volatilization at high temperatures in a strong current of steam and preferably under diminished pressure, such unsaponifiable matter may be condensed with the glycerine in which it is substantially insoluble, and removed with ease from the glycerine. Althou h I prefer to collect the glycerine which disti s over during the carrying out of my process in a state of high concentration by resorting to fractional condensation, I may employ the type of condensation which will result in condensin glycerine and a considerable portion of t e steam em loyed so as to give a more dilute glycerine so ution. This may be separated with'ease from unsaponifiable matter or fatty acids, both of which are substantially insoluble in glycerine or in dilute glycerine solution, and concentrated by simp e well-known means to a concentrated glycerine. Glycerine as obtained by my process is of a suflicient degree of purit to be directly applicable to many uses. t may, however, be readily purified to a very high de-. gree of purity by subjecting it to an additional distillation, as by the well-known process of vacuum distillation with the aid of steam under diminished pressure.

In removing all orv a portion of the soap formed by my process after removal of glycerine and unsaponifiable matter, I prefer to draw it off in liquid state while taking suitable precautions to exclude contact of air pipe from air and keep it free. The soap may be discharged into and beneath the surfaceof a mass of water or hydrated melted soap and the amount of water employedneed not be greater than that necessary to leave an amount of water in the finished soap substantially e uivalent to that obtained in other soap-ma ing processes. I may also use other means of drawing oil the hot soap formed in my process in such a manner as to exclude air from it while it is at a temperature that would cause the air to exert a deleterious action, but these need not be detailed as the do not form a part of my present process. oap obtained in this way is suitable for use by itself or may be made into toilet or laundry soap, or soap powders, by any of the well-known methods of utilizing soap.

There are some low grade fats and fatty oils which contain so -much objectionable coloring matter that they are not fit to make directly into soap by any process without resorting to distillation of their fatty acids. My process efi'ects suflicient improvement in certain low grade fatty matter so that distillation is rendered unnecessary, but it may be employed in exceptional cases in conjunction with distillation of fatty acids so as to effect improvements that may not otherwise be effected. For this purpose distilled fatty acids obtained by known methods may be fats and fatty oils. Some of them, as for instance wool grease, are saponified incompletesaturated in varying degrees but which may also be separated from natural fats and fatty oils by hydrolysis, and to such other organic acids as yield soaps on treatment with alkaline or basic media.

Soaps as commonly made are melted with the aid of a water content. This water content on the freshly made soap approximates thirty per cent. When such soaps are subjected to temperatures slightly in excess of 100 degrees 0., the boiling point of water, they lose their water rapidly and eventually become anhydrous or substantially anhydrous. At the higher temperatures employed in my process water is even more volatile and soaps become substantially anhydrous even though it is probable thatthey may contain traces of water. When hereinafter I use the term anhydrous soa it means substantially anhydrous and res from all but traces of water. 7

I hereinafter in the claims intend the term fat to include any fats and/or fatty oils or glycerides which are useful either singly or as mixtures in the manufacture of soaps by common soap-making methods.

I hereinafter in the claims intend the term low gradefat to include any material containing quantities of fat and also containing such other substances as render the low grade fat objectionably odorous and/or colored or susceptible of becoming objectionablyodorous and/or colored. Such low grade fats include, among others, marine animal oils or fats, certain grades of vegetable oils or fats,

house grease and garbage extraction grease.

By thorough agitation I hereinafter mean that degreeof turbulation, induced by rapid flow through a conduit or by-stirring, either mechanical or by. means of vapor, which is sufiicient to prevent local overheating or high temperature gradients and sufficient to insure uniformity of temperature in and throughout the mass of material which is being heated by'means of heat applied to surfaces with which the material is in contact.

While I have hereinbefore described in detail a limited number of forms of my invention, I do not wish to be narrowly bound by any of the quantity proportions or condi tions described, but what I wish to secure by Letters Patent is the true spirit of my invention as represented by the scope of the appended, claims.

What I claim as my invention is:

1. The process of making soap and glycerine which consists in heating a mixture of fat and a base to a temperature in excess of the meltin 'point of theresulting anhydrous soap and thoroughly agitating the mixture in an atmosphere free of air while intimately contacting the mixture with astream of water vapor.

2. The process of making soap with an unobjectionable odor and glycerine which consists.in heating a mixture of low grade fat and a base to a temperature in excess of the melting point of the resulting anhydrous soap and thoroughly agitating the mixture in an atmosphere free of air, while intimately contacting the mixture with a stream of water vapor.

3. The process of making soap with an un- I objectionable odor and glycerine which consists in heating a mixture of low grade fat and a base to a temperature in excess of the melting point of the resulting anhydrous soap and thoroughly agitating the mixture in an atmosphere free of air, while intimately contacting the mixture under diminshed pressure with a stream of water vapor.

4. The processofmakinglight-coloredsoap with an unobjectionable odor and glycerine which consists in heating a mixture of low grade fat and a base to a temperature in excess of the melting point of the resulting anhydrous soap and thoroughly agitating the mixture in an atmosphere free from air, while intimately contacting the mixture with a stream of water vapor.

5. The process of making light-colored soap with an unobjectionable odor and glycerine which consists in heating a mixture of low grade fat and a base to a temperature in excess of the melting point of the resulting anhydrous soap and thoroughly agitating the mixture in an atmosphere free from air, while intimately contacting the mixture under diminished pressure with a stream of water vapor.

fat and of separating the resulting glycerine in vapor form from the soap which comprises uniformly heating a mixture of fat and an 6. The process of completely saponifying alkaline medium to a temperature in excess of the melting point of the resulting anhy-. drous soap while contacting the said mixture with a stream of water vapor at low pressure, excluding air, and condensing the glycerine.

7. The process of completely saponifying fat and of separating the resulting glycerine in vapor form from the soap which comprises uniformly heating a mixture of fat and an alkaline medium to a temperature above degrees C. while contacting the said mixture with a stream of watervapor at low pressure, excluding air, and condensingthe glycerine.

8. The process of manufacturing soap and glycerine, one from the other separated,

10 melting point when anhydrous, excluding subatmospheric,

stantially all air from the melted mixture, intimately contacting the melted mixture with a current of steam and carrying the glycerine from the melted mixture by the current of steam.

10. The process of manufacturing soap containing substantially no glycerine wh ch comprises heating a soap and glycerlne mixture uniformly to a temperature in excess of its melting point when anhydrous,"exclud1ng substantially all air from the melted mrxture, intimately contacting the melted mixture with a current of steam at a pressure less than and carrying the glycerine from the melted mixture by the current of steam.

11. A process for the manufacture of soap and glycerine consisting in the treatment of fats or fatty oils with an alkaline med um suflicient to effect saponification, the sub ection of the composition thus formed to heat, without local over-heating, to a temperature in excess of 200 degrees agitation, with the exclusion of air, with a current of steam, in a closed vessel with the aid of diminished pressure for the volatilization and recovery of the glycerine pro duced, and for the volatilization and removal of volatile impurities.

12. A process of making soap and glycerine consisting of mixing fats or fatty oils with an alkaline medium, heating the mixture thus formed, with the exclusion of air, withagitation, without local overheating, to a temperature in excess of the melting point of the an hydrous soap, with the employment of a current of steam, volatilizing, condensing and recovering the glycerine thus formed, and volatilizing and removing objectionable volatile impurities.

13. The process of makin bland, sweetsmelling soap from fatty aci s derived from marine animal oilsconsisting of mixing such fatty acids with an alkaline medium, heating the mixture thus formed with the exclusion of air, with agitation, without local overheating, to a temperature in excess of 250 degrees 0., with the employment of a current of steam, in a closed vessel under diminished pressure, volatilizing and removing objectionable impurities.

14. The process of saponifying esters of fatty acids to produce soap and alcohol and of separating the resulting alcohol in vapor form from the soap, which comprises uniformly heating a mixture of esters of fatty with the aid oftating the whole, and condensing the alcohol so formed.

15. The process of saponifying esters of fatty acids to produce soap and alcohol and of separating the resulting alcohol in vapor form from the soap, which comprises uniformly heating a mixture of esters of fatty acids and an alkaline medium to a temperature above 150. degrees C. while contacting said mixture with a stream of water va r at low pressure, excluding air, thoroug 1y agitating the whole, and condensing the alcohol so formed.

16. The rocess of separating glycerine from a partially saponified and sapon ifying mixture of a fat and a base which consists in uniformly heating the mixture in the presence of water vapor to a temperature producing an appreciablevapor pressure of glycerine, continuously and thoroughly agitating said mixture to revent local over-heating, excluding air, intimately contacting said mixture with a stream of watervapor, removin the mixed vapors of water and glycerine and condensing the glycerine.

17. l he process of separating glycerine from a mixture of soap and glycerine which consists in heating sald mixture uniformly without local overheating to a temperature producing an appreciable vapor ressure of glycerine, thoroughly agitating said mixture, excluding air, intimately contacting said mixture with a stream of water vapor, and removing the resulting mixed vapor of water and glycerine and condensing the same while carrying on the whole at diminished pressure.

18. The process of converting soap with an objectionable odor into soap without an objectionable odor which consists in heating,

said soa to a temperature above its melting point w en anhydrous thereby driving substantially all water therefrom, agitating to maintain substantially uniform temperature throughout said soap regardless of heating means, and excluding air while contacting said soap with a fiow of water vapor at a pressure low enough to prevent the existence of liquid water.

19. The process of converting soap with an objectionable odor into soap without an objectionable odor, which consists in heating said soap to a temperature in excess of 150 degrees 0. thereby driving substantially all water therefrom, agitating to maintain substantially uniform temperature throughout said soap regardless of heating means, and excluding air while intimately contacting said soap with a flow of water vapor at a pressure low enough to prevent the existence of liquid water.

ing soap, while continuously distilling glyccrine from the soap thus formed.

21. The process of making soap and glycerine which comprises the addition of successive quantities of a mixture of fat and a base to a partly filled vessel in the presence of steam within said vessel for the purpose of forming soap, applying heat to the mixture while continuously agitating the mixture to prevent local overheating, maintaining the mixture at a temperature in excess of 200 degrees (3., removing successive and substantially corresponding quantities of soap from the vessel while contacting the contents of the vessel with a stream of water vapor, while maintaining diminished pres sure within the vessel.

22. The process of h drolyzing fat which consists in mixing'the at with soap, heating the mixture to a temperature between 150 and 350 degrees 0., thoroughl agitating the mixture, excluding air there rom, and contacting the mixture with water vapor at a pressure low enough to prevent the existence of liquid water.

MARTIN HILL ITTNER.