US2004874A - Product and process for preparing same - Google Patents

Description

Patented June 11, 1935 UNITED STATES PATENT OFFICE Wilbur Arthur Lazier, Marshallton, DeL, assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Dela No Drawing. Application August 18, 1932,

' Serial No. 629,307

11 Claims.

' invention relates to soaps and soap-making processes, .and more particularly to a new type of superfatted soap and processes for manufacturing the same.

5 This'invention is dependent upon and is an outgrowth of my discovery of a novel and economical method for the production of fatty alcohols of highmolecular weight through catalytic reduction with hydrogen of fatty carboxylic acids l :and their derivatives as disclosed in Lazier U. S.

Patent 4,839,974 and copending applications Serial No. 445,224, filed April 17, 1930, and Serial No. 520,473, filed March 5, 1931. Soap-making is an art of considerable antiquity and as a consequence. has suflered few chemical changes of'afundamental nature in modern times. The introduction of catalytic hydrogenation as a' fat hardening process, while profoundly affecting the supply of fatty materials potentially suitable forsoap-making, has not resulted in an appreciable alteration in the characterv of the product produced, since substantially saturated glycerides were already available from natural sources before the discovery of the hardending 25 process.

an alcoholic nature as have been occasionally employed in soap-making have been as a rule andof necessity produced by artificial means by processes that were often prohibitively costly. Various 30 so-called fillers such as wax, petroleum products, and ground mineral substances are commonly incorporated into soap as cheapening agents and without meritorious improvement in the quality of the product. On the other hand 35 certain fillers such as rosin and the hydrogenated phenols and naphthols are known to improve the detergent power of the soap and render its use against mineral grease and in hard waters more economical than would otherwise be the case.

In 1885 Unna introduced the practice of adding unsaponified fat to soap for the purpose of aiding in the retention of medicinal agents. Various other advantages of superfatting have since been recognized, particularly in connection with the manufacture of fine toilet soaps, although the use of fats as originally proposed has given trouble with the development of rancidity. Wool fat or lanolin is less objectionable for this purpose on account of its high content of cholesterin, and has been extensively used as a superfatting material.

It is an object of this invention to improve upon the quality of fine soaps and methods for their manufacture through the application of newly discovered processes for the preparation On the other handsuch compounds of process the necessary steps required for the preparation of soaps containing higher fatty alcohols as the superfatting agents. Other objects will appear hereinafter.

I have now found in accordance with this invention that the non-cyclic or open-chain synthetic higher alcohols or mixtures of alcohols possessing from 8 to 20 carbon atoms derived from the naturally occurring fatty acids by direct catalytic hydrogenation at high temperatures and pressures are particularly well suited for use as. agents for the superfatting of soap and soap products. I have determined further that the processes of catalytically preparing higher alcohols and the processes of soap manufacture are so related as to make it economically and scientifically desirable to combine the necessary operations into a unified process. Broadly considered, the process of my invention may therefore be regarded as a novel method for the manufacture of superfatted soap of a special kind.

In accordance with my invention I may produce a super-fatted soap by taking a semi-finished or stock soap of neutral reaction and high quality and adding thereto an appropriate amount of a fatty alcohol having from 8 to 20 and preferably from 8 to 15 carbon atoms and separately prepared from a fatty acid or fat by catalytic hydrogenation. The mixture of soap and alcohol is then milled until uniform in appearance and texture and is molded in the usual manner.

Alternatively I may add the pure alcohol to the fats or oils prior to saponification or I may carry out a hydrogenation process on a small part of soap stock to convert it rather completely to alcohols, then mix with the remainder of the stock and carry 'out'thesaponiflcation. Still another method of carrying out the invention is to subject the entire lot of soap stock fats to a very mild hydrogenation whereby only a small part of the glycerides is converted to alcohols. Where liquid fats are employed that require hardening, the production of a sufiicient concentration of fatty alcohols may be obtained simultaneously with the hardening process by carrying out the necessary hydrogenation in the presence of a suitable catalyst and at sufficiently high temperatures and pressures. Having treated the soap stock in such a manner as to produce th -Min the carried out in such a way as to produce a highyield semi-boiled soap. Soaps containing fatty alcohols may also be produced from such special stocks by the cold process, i. e., by treatment of the soap stock at temperatures below the boiling point, e. g., the soap stock may be heated to its melting point, and the caustic alkali then added.

Having now outlined in a general way how I carry out my invention I will present specific examples showing in detail how I proceed to practice the invention.

Example 1.-A smooth white toilet soap having good detergent properties is preparedas follows: A fine white boiled stock soap is procured by saponification of fresh odorless tallow containing to give a product essentially free from salt and unsaponified fat, and containing not more than 0.2% of free caustc soda. One hundred pounds .of the stock soap is chipped and milled with 8 pounds of stearyl alcohol (prepared by the hydrogenation of pure stearic acid), 4 pounds of starch and 16 oz. of a suitable perfume blend. When the mass is perfectly homogeneous, the charge is passed through a plodder and cut into cakes which are compressed to bars of suitable shapes. Instead of the milling process the stock soap and the stearyl alcohol may be melted, the other fillers and perfumes added and the charge framed, cut and pressed. 7

Example 2.A suitable textile soap filled with molecular weight fatty alcohols is prepared as follows: Mix together with the aid of heating 900 pounds of palm-kernel oil, 600 pounds of cottonseed oil and 4 00 pounds of tallow. Withdraw 200 pounds. of the mixed fat and subject this portion to catalytic hydrogenation at 385 'C. and 2,000 pounds pressure-'by passing it continuously with an excess of compressed hydrogen over a catalyst consisting of mole of zinc chromite and 15 mole of copper chromite. The rate of flow of the oil over the heated catalyst should be about -8 times the catalyst space per hour and the hydrogen-glyceride mole ratio should be about 20. The composition of the processed oil corresponds to about 85% conversion of the fats to the fatty alcohols. Thecrude hydrogenated oil is added to the main portion or unhydrogenated part and the mixture is run into and boiled with 1555 pounds of caustic soda lye of 30 B. The charge is sprinkled with 50 to 100 pounds of Be. brine, finished with pounds of fresh palm-kernel oil, and allowed to settle, after which it is framed and molded in the usual manner.

Example 3.-A coldprocess toilet soap containing lauryl and other alcohols is prepared as follows: One hundred pounds of coconut oil is mixed with 8 pounds of copper chromite powder and is heated to 250 C. in a stirring autoclave under a hydrogen pressure of 100 atmospheres until the decrease in the hydrogen pressure corresponds to the theoretical value for hydrogenation of 5-8% of the carboxylic groups in the oil. The oil is cooled, filtered and mixed with 50 pounds of'38" B. soda lye in a stirring kettle at a temperature of 35 C. When saponification is complete and the mass commences to thicken, it is perfumed and run off into frames in which it is allowed to congeal slowly. If a low-priced prodnot is being prepared the perfume may be omitted since the lower boiling members of the coconut oil alcohols contribute a considerable desirable odorto the product.

Example 4.--A castor oil soap is prepared as follows: Castor oil is subjected tocatalytic hydrogenation by passing it continuously with'hyd-rogen over a catalyst prepared by coprecipitating the chromates of zinc, copper and cadmium in the molecular ratio of 82.5: 10:75 and igniting at 600 C. to form the corresponding chromites. ;The

temperature of the hydrogenation is 390? and rate of 4 times the catalyst volume per hourv with a sufiicient amount of hydrogen to give 10 moles per mole of combined ricinoleic acid. The decrease in the saponification value resulting from hydrogenation of the estergroups is about 60% while the iodine number is lowered from I 85 to 55. The product is fluid and isv subjected 10% of coconut oil with sufficient caustic soda to a second hydrogenation with a reduced nickel catalyst at and 150 pounds hydrogen pressure whereupon the oleflnic groups become saturated. The oil congeals to a white solid and possesses a fragrant odor. Analysis of the product at this stage has shown it to contain octadecanediol, stearyl alcohol and certain alcohols of .lower molecular weight such as heptyl and undecyl alcohols, together with a residuum of hardened castor oil and synthetic waxes. The product is convertedto a highly superfatted soap by saponiflcation with the theoreticalamount of caustic soda calculated from the saponification number determined after hydrogenation. Since the content of higher alcohol is higher than normally desiredin a commercial superfatted soap, it is convenient to employ a product prepared as just described as a. stock material for superfatting soaps from other sources. For example a white stock toilet soap may be admixed with castorf soap and octadecaneidiol by melting or milling it with 10-15% of the octadecaneidiol stock prepared as described above.

All of the fats and oils now employed for-soapmaking are applicable to the present invention. These may be of either vegetable or animal origin. The free fatty acids may also beused and the esters of these with alcohols other than glycerol. These may correspond with the existing fats or may be. from a synthetic or mineral source such as, for example, the naphthenic acids. The

amount of alcohol compounded with the soap stock may vary between wide limits, the preierred amounts ranging between 1 to 50% of the final product.

In carrying out the hydrogenation of the fatty acids, esters, etc., the catalyst may consist of almost any hydrogenating metal such as zinc, copper, cobalt, nickel or platinum or preferably of a difficultly reducible hydrogenating oxide, I

such as copper oxide in comblnation'with chromium oxide, zinc oxide, or manganese 'oxide. Suitable temperatures are found in'the range of 200-450 C. and suitable pressures above 10 atmospheres.

The fatty materials hydrogenated to produce the higher alcohols may be fatty acids, their esters, amides, salts and chlorides. These materials are all embraced under the term.atty acids and their derivatives. 7

The alcohols to be introduced into the soap by the methods outlined are high boiling liquids or solids, usually having straight chains of a considerable number of carbon atoms, say, from 8 to 20 and preferably 8 to 15. 'Aicohols containing naturally either as free alcohols or as esters- They will therefore be referred to .as synthetic alcohols, and the scope of the invention will be construed as covering only those alcohols which are prepared by catalytic hydrogenation of the corresponding acid, ester, etc. The more important alcohols within this class are octyl, nonyl, decyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, palmityl, margaryl, linoleyl, oleyl, hypogaeyl, ricinoleyl, stearyl, and nonadecyl.

By introducing fatty alcohols into soaps I do not mean to imply that other fillers are'necessarily to be replaced or excluded. 'In addition to the fatty alcohols valuable soaps may contain also such substances as aliphatic, aromatic, or hydroaromatic hydrocarbons, hydrogenated phenols, paraffin and other waxes and resins, naphthalene, drugs, etc.

The advantages of incorporating higher fatty alcohols into soaps and soap products are several.

The higher alcohols impart to the soap and to the products washed with it a' smooth, soft feel that is not produced in the absence of the alcoholic fillers. Textiles remain, after washing, in a soft, fluffy condition and the effect on the skin is such as is free from the harshness ordinarily resulting from complete removal of the natural oils with ordinary soap. In the use of the fatty alcohols for superfatting, these advanges are gained without risk of rancidity since the fatty alcohols are immune to fermentation processes and probably possess mild germicidal power of their own. In the manufacture of toilet soap the solid higher alcohols increase the capacity of a soap of a required hardness for retaining water, impart an improved grain or texture and result in an improved gloss on the surface of the polished bar. Depending somewhat on the local conditions, the use of the fatty alcohols may be an aid to detergency under the exacting conditions encountered with sea water or other mineral-containing waters. There is an additional advantage connected with the use of the more volatile alcohols derived from the coconut oil, acids or prepared bythe destructive hydrogenation of castor oil, for these alcohols have strong perfuming qualities. 'By employing in the soap-making process stocks containing the appropriate oils and subjectiiig these stocks to a preliminary and partial hydrogenation under conditions suitable for recarrying out the hydrogenation of a. fat or fatty acid or ester to form alcohols, the reaction is never complete, making it necessary to subject the crude hydrogenation product to a careful purification and separation in order to isolate the pure alcohol. By combining the hydrogenation with the saponification incident to the soapmaking, the unhydrogenated portion of the crude alcoholic product is destroyed without additional expense and with the advantage that an equivalent amount of soap is produced. By subjecting mixed soap stocks to hydrogenation it is possible to vary greatly the character of the fatty alcohols entering the soap and hence alter the properties of the finished article. There is yet another advantage. As already pointed out, it is common practice to harden certain soap fats and it is entirely feasible to produce alcohols during the hardening process and without much extra expense provided suitable temperatures, pressures, and catalysts are selected.

I am fully aware that a notable advance in the art of detergency has recently been made through the development and use of sulfonated higher alcohols and hydrocarbons. I lay no claim to any such processes, restricting my invention to the uses of the derived fatty alcohols themselves as adjuncts to soap.

The above description and specific examples are illustrative only and are not intended to limit the scope of the invention. Any modification or variation corresponding to the spirit of the invention is intended, to be included within the scope of the claims.

I'claim:

1. A soap containing an aliphatic open-chain alcohol, having from 8 to 20 carbon atoms, and corresponding to a fatty acid which is contained in naturally occurring fats.

2. The soap described in claim 1, characterized in that the alcohol contains from 8 to 15 carbon Y 3. The soap described in claim 1, characterized in that the alcohol is one obtainable from the catalytic hydrogenation of soap stock.

4. The soap described in claim 1, characterized in that the alcohol is one obtainable from the catalytic hydrogenation of coconut oil.

5. The soap described in claim 1, characterized in that the alcohol is one obtainable from th catalytic hydrogenation of castor oil.

6. The soap described in claim 1, characterized in that the alcohol is lauryl alcohol.

7. In a soap-making process the step which comprises commingling a soap and an aliphatic open-chain alcohol, having from 8 to 20 carbon atoms, said alcohol corresponding to a fatty acid which is contained in naturally occurring fats.

8. A soap-making process described in claim 7, characterized in that the alcohol contains from 8 to 15 carbon atoms.

9. The soap-making process described in claim 7, characterized in that the alcohol vis produced by the catalytic hydrogenation of the corresponding fatty acid. 7 v f 10. The soap-making process described in claim 7, characterized in that the soap is produced from soap stock that is intimately mixed with said alcohol.

11. The soap-making process described in claim 7, characterized in that the alcohol is produced by the catalytic hydrogenation of the correspond ing fatty acid and the soap is produced in the presence of said alcohol.

WILBUR A. LAZIER.