US2094127A - Mixed higher alcohols - Google Patents

Description

Patented Sept. 28, 1937.

UNITED STATES PATENT OFFICE MIXED HIGHER ALCOHOLS Wilbur A. Lazier, Marshallton, Del., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application January 2, 1932, Serial No. 584,575

2 Claims.

This invention relates to new compositions of matter and more particularly it pertains to novel and useful mixtures produced from naturally occurring fatty acids and esters of high molec- 5 ular' weight. This application is in part a continuation of my ing alcohols, and the hydrogenation may be controlled to produce substantial amounts of esters from it by the interaction of the higher alcohols and unreduced fatty acids or esters. The present invention deals with those products which are obtained by treating naturally occurring mix- 20 tures of fatty acids or esters to produce new and useful mixtures of alcohols and/or related esters, said treatment involving the step of catalytically reducing the fatty acid material with hydrogen in the presence of a catalyst.

One ,object of the invention ,relates to novel I reduction products of naturally" occurring mixtures of fatty acids and esters, or of derivatives of said fatty acid materials which contain the acid radical. A more specific object of the" invention pertains to 9,10-octadeceny1-octadecyl alcohol mixtures, to mixtures of alcohols produced by the reduction of coconut oil acids and their esters, and to mixtures containing higher,

alcohols and wax-like esters of such higher alcohols. Other objects of the invention will become apparent from the following description of the invention.

My copending' applications above referred to describe highly satisfactory methods for treating naturally occurring fats and fatty acids to produce the corresponding alcohols. satisfactory character of these processes make possible the production on a commercial scale of many higher alcohols, the manufacture of which has either been impossible, or has been prohibitive due to the expense involved. By applying the "processes described in the said applications to the hydrogenation of naturally occurring fats,

. oils, high fatty acids, and acid derivatives thereof, it has been possible to produce rnixtures of alcohols and/or wax-like esters which are sus ceptible of use directly in the arts without separation into their components. Furthermore, many of these mixtures due to their inclusion of several components of differing molecular weights The highly and physical and chemical properties are much more satisfactory for use than the individual components when used separately.

Of particular interest as new and useful compositions are (1) the novel mixture of saturated and unsaturated straight chain higher alcohols resulting from the carboxyl hydrogenation of oleic acid or of the liquid fats and oils or of the acids contained. in such oils or fats or acids prepared therefrom by saponiflcation or of the al- 1 kyl esters of the aforementioned fatty acids; (2) the mixture of alcohols derived from coconut oil or its acids containing saturated alcohols-having from 8 to 16 carbon atoms; (3)' mixtures of higher alcohols and waxy esters formed under controlled conditions upon hydrogenation of nat urally occurring oils and fats or the acids prepared therefrom by hydrolysis.

From the economic standpoint, there is a distinct advantage in employing mix ures of the 20 type illustrated in the arts rather than the isolated compounds. The individual alcohols canv be separated from the mixtures only by means of tedious 'distillations or crystallizations which add materially to the cost of manufacture. particularly diillcult to separate the unsaturated components from those which are completely saturated. 1 It is to be noted that the separation and'purification of fattyacids and esters from mixtures thereof prior tohydrogenation .is likewiseextremely expensiye and in most cases practically impossible. There a real advantage therefore in producing alcohol by hydrogenation from mixtures of fattyacids and/or esters from the standpoint of cost /of production alone.

Aside from economic consideration, an extensive study of the possible applications pf the reduction products of fatty acids and esters have shown that there are many uses where unseparated mixtures of reduction products have greater 40.

utility than the pure components when used separately. i I

The following discussion will illustrate this comparative utility.

l. 9,1o-octadecehyl-octadecyl alcohol mixtures As prepared by the synthetic method, these mixtiires differ from the pure compounds in melting point and viscosity. As already pointed out it/ is difficult to prepare either alone by direct 50 conditions and catalyst used. These higher alco- 55.

It is 25 oration rates.

hols may be substituted with advantage for stearic and oleic acids in rubber compounding. For this purpose it is undesirable to use a softener or modifying agent that is either too hard or too fluid. Consequently it is found that certain mixtures as prepared by direct hydrogenation of the acids have about the proper consistency for this purpose. Another use is found in the oiling and waxing of textile materials, Where it is desirable to inhibit the formation of large wax crystals. In the formulation of nitrocellulose compositions unsaturation improves the compatibility of alcohols but tends to make the product less stable to oxidation. By the use of the synthetic mixtures, compositions may be prepared in which both reasonably good compatibility and stability are obtained. The same resuits may be obtained with mixed esters prepared by esterifying the alcohol mixtures. For example promising results have been obtained in the use of mixed 9.10-octadecenyl and octadecyl phthalates and adipates as softeners for nitrocellulose and resin base coating compositions. Viscosity and melting point and particularly the relationship between temperature and viscosity are important considerations in the formulation of lubricants. In the use of synthetic higher alcohols these properties are most influenced by the degree of unsaturation. By theproper control of the hydrogenation of cottonseed oil an alcohol mixture containing a preponderance of both saturated and unsaturated alcohols having 18 carbon atoms may be obtained having a consistency suitable for use in the manufacture of a non-corroding cup grease.

2. Coconut oil alcohols These materials differ from the pure compounds in having graded boiling and melting points, solubilities in water, viscosities and evap- In addition, the lower members are useful perfume constituents while the higher members are practically odorless. Higher alcohols find use in soap manufacture for the improvement in detergent power, particularly when used in hard water as evidenced by the use of cyclohexanol and its derivatives. They also impart a quality that tends to lessen the harshness of the soap on theskin as a result of a too complete removal of the fat particles. Glycerine has been' used for this purpose but it is too soluble in water to be efiicient. The use of a mixture of the whole product obtained by hydrogenating coconut oil in soap stock has a distinct advantage over the use of any one of the pure alcohols for it is the higher boiling components such as dodecyl and tetradecyl alcohols that are beneficial as cleansing and softening agents while the lower members such as octyl alcohol impart a desirable fortifying action to the added perfumes. In using the coconut oil alcohols as lubricants, for example in cutting oils, the various gradations in properties desired are obtained by selecting the oil or acid stock to be hydrogenated.

3. Synthetic wares plus was: alcohols As has'been pointed out in my copending applications already referred to, the incomplete hydrogenation of a higher fattyacid or of an ester of the same will result in the formation of both higher alcohols and esters, the esters being formed by interaction of the higher alcohol and the acid or ester remaining unreduced. Where a naturally occurring fat or oil or where amixture of acids obtained therefrom as by saponification is subjected to incomplete hydrogena- V tion, a reaction product is obtained which contains both a mixture of higher alcohols and a mixture of esters formed by interaction of these alcohols with the unreduced fatty acid radicals. The esters produced from fatty materials have a. distinct wax-like consistency. The proportions of the components may be varied over a wide range by adjusting the operating conditions that control the efficiency of the hydrogenation. These ester-alcohol mixtures have wide utility in the arts both on account of the low cost of their manufacture and by reason of their unique properties. For example, higher alcohols are strong fortifiers for increasing the compatibility of wax with pyroxylin, particularly where toluene is used as the diluent. Consequently, the synthetic waxes containing higher alcohols can be combined with pyroxylin-toluene systems in higher concentrations than when wax alone is used. In addition to their effect with nitrocellulose, the heat digestion of waxes with phthalic anhydride is greatly improved if waxes are fortifled by the inclusion of higher alcohols. Useful results are also obtained in the use of synthetic wax-higher alcohol mixtures for delustering artificial fibres such as rayon. Another use for the wax-higher alcohol mixtures is in the preparation of pyroxylin containing emulsions or rubber latex for impregnating'cloth. Other uses than the ones enumerated readily suggest themselves from the general utility of these mixtures as described.

The following examples which are illustrative only are given to indicate methods for producing the novel compositions described herein.

EXAMPLE 1 Hydrogenation of mixed coconut oil acids An effective catalyst comprising a mixture of the chromites of different hydrogenating metals and containing also some of the oxides of these metals was made in the following manner: A solution was prepared by dissolving 245 parts by weight of crystallized zinc nitrate, 23 parts of hydrated cadmium nitrate" and 24 parts of copper nitrate (trihydrate) in about 750 parts 01' water. A second solution was prepared by mixing 100 parts by weight of chromic anhydride in 500 parts of water and then adding 135 parts of 28% ammonium hydroxide. Precipitation of the hydrogenating metals of the first solution as chromates was effected by stirring and adding at room temperature the second solution. The mixture was exactly neutralized by additional ammonium hydroxide and allowed to settle. The liquid was poured off and the precipitate washed several times by decantation after which it was filtered and dried at 400 C. The dried residue was ignited for four hours, the double ammonium chromates of copper, zinc and cadmium being converted to metallic chromites. The material was then granulated to a. friable chromite powder and briquetted'into the form of tablets. A good commercial grade of mixed coconut oil acids was hydrogenated continuously by pumping it together with hydrogen over 100 cc. of the catalyst prepared as described above while maintaining a temperature of about 380 C., the acids being pumped at the rate of about 200 cc. per hour. The hydrogen pressure was 2500-3000 lbs/sq. in., and the rate of flow of the-hydrogen was about 15 cu. ft. per hour. Analysis of the crude product v v 2,094,127: 0.8% acid calculated as lauric acid. Eight dred fifty g. of coconutoil acids yielded 681 g.

of mixed alcohols, corresponding to a yield of about 85% of the theoretical.

EXAMPLE 2 Oleic acid provides a very suitable starting point for the synthesis of 9,10-octadecenyl and octadecyl alcohols and their esters. Owing to its low melting point, oleic acid is more convenient to pump than stearic acid, and the selection of optimum conditions for its hydrogenation has been more thoroughly investigated than for some of the other acids. Pure oleic :acid was pumped over 100 cc. of the catalystdescribed in Example 1 at the rate of.400 cc. per hour. The hydrogen flow was about 15 cu. ft. per hour and the pressure 2800 lbs/sq. in. The temperature was varied between 350 C. and 420 C. and the product collected at each temperature was analyzed for acid, ester, and alcohol. following table:

Composition of product Temperature Percent Percent 301d Percent Percent total ester alcohol 19 36 39 94 S 36 50 94 6 34 B 98 2 30 68 100 2 29 67 98 2 I 26 93 1 21 60 82 It is apparent that the lower temperatures favor the formation of waxes, which at the higher temperatures are hydrogenated further to the free alcohols. The /optimum temperature .is about 390 C. p

EXAMPLE 3 I Commercial coconut oil was also-successfully hydrogenated at a temperature of 380 C.-a'nd a total pressure of about v2700 lbs/sq. in. The standard hydrogenation catalyst described in Example 1 was slightly reduced in hydrogen, preliminary to the introduction of the fat: 'Theoil was passed over the catalyst at the rate of 400 cc.

of liquid per 100 cc. 'ofcatalyst per hour, whilehydrogen was put throughat the rate or 125, cu. ft. per hour. Assuminga mean molecular weight of about 60,0 'for'theglycerides,- this amount of hydrogenwas roughly'equivalent to eight moles per mole of esteri'fied fatty acid; The treated oil was separatedirom the excess. hydrogen without difficulty and was recoveredalmost quantitatively. The conversion of esters to alcohols as measured by decrease in the saponification value amounted to about 70% and there was no evidence of catalyst deterioration after 42 hours of continuous operation. The condensate contained about 30 cc. of water per liter,whichwas probably formed by dehydration of a part of the glycerol liberatedby hydrogen tion of the mixed gl-ycerides.

Where it is desired to form amounts of waxes greater than the amount normally formed intollowing out the conditions of the above examples,

the pressure is preferably decreased below 2500 lbs/sq. in., the greater the decrease :in pressure-,'

the greater the proportional ester wax formed.

The same result may'be obtained :by diminishing theratio of hydrogen to the fatty material be,-'-

ing hydrogenated, by lowering the temperature,

hun-

The results are shown in the J ucts.

Exmru: 4

One hundred cc. of the ester hydrogenation catalyst prepared as in Example 1 was placed in a steel reaction vessel capable of withstanding high pressures and was slowly heated to 380 C. in a stream .of hydrogen. ,The exit valve was then "closed and the hydrogen pressure allowed to build up to v2700 lbs/sq. in. At this temperature and pressure, refined cottonseed oil was pumped over the catalyst at the rate of about 400 cc. per hour, while hydrogen was drawn through the system at thev rate of about cu. ft. per hour, asmeasured underordinary conditions of temperature and pressure at the exit of the reaction system. The treated oil was separated from the excess gas under pressure by passage through a trap before expanding to atmospheric pressure. The untreated oil hada saponification value of 195 and an iodine-. value of 115. After the hydrogenation treatment the saponification value of the product was 49 and the iodine number 89 indicating a 75% hydrogenation of the carboxyl groups of the;,fatty acids of the g ycerides .with only a 23% -reduction in the olefinic unsaturation. Practically? no free acid was formed. The activity 0'! the catalyst was undiminished after'67 hours of continuous operation, and upon opening the tube gave no evidence of deterioration due to the deposition of carbon or resinous organic matter. That the reduction in saponification value of the 'glycerides had taken place through the medium of hydrogenation of thecarbonyl groups to primary alcohols was demonstrated by a rise'inthe acetyl value of the product corresponding closely to the observed decrease in the saponiiication value. The product was a semi-solid mass having a pleasant odor reminiscent of some of the simpler. normal higher alcohols. i I

Olive 01] maybe hydrogenated in 'the same manner as described above for cottonseed oil yielding a mixture of alcohols consisting substantially of 9,10-o'ctadecenyl and octadecyl alcohol. 3

Temperatures as, low as 200 C. may be used inv conducting the'hydrogenation reactions, but the most satisfactory results are obtained between 300 and 400 0., depending somewhat on the catalyst composition selected and on the chemical nature of the fatty material to be reduced.

The minimum temperature at which it is desirable to operate is about IOatmospheres, the b esLresults being-obtainedat higher pressures,

, usually between 100 and 205 atmospheres. Elevated temperatures and pressures are essential to the success of the process but within the op erative limits 0; temperature and pressure, the temperature is the most important factor in determining-*the yield of the-hydrogenation prod- Thus, when the reaction is conducted at the higher'temperatures with the lower operative pressures the yield is much greater than is ob tained when the lower temperatures are used Lil ,fatty acids or their anhydride's.

with the higher pressures. The higher temperature limit isgdetermined by the temperature at which undesirable decomposition takes place and insofar as I am aware the higher operative pressures are limited only by practical considerations for obtaining exceptionally high pressures. The optimum pressure will vary somewhat depending on the acid treated, the degree of hydrogenation required, and the specific character of the catalyst.

' With respect to the ratio of hydrogen to the fatty material undergoing treatment, I prefer to use an excess of hydrogen preferably from 2 to 10 moles per mole of combined fatty material.

The rate at which the material may be passed over the catalyst is a function of the average molecular weight of the fatty material and the catalytic activity of the contact mass. Ordinarily from 2 to 8 volumes are passed per hour per unit volume of catalyst, but higher. rates may be employed atthe expense of slightly lower conversions. The production of the wax-like materials is increased by incompletely or partially hydrogenating the fatty material and then heating the partially hydrogenated material above 200 C., if sui'iicient heating has not already taken place in the process. The partial hydrogenation may be effected by using the low operative temperatures and either increasing the rate of flow of the fatty material or decreasing the rate of flow of the hydrogen. A still further yield of the wax-like products may be obtained by heating the partially hydrogenated fatty material with more of the unreduced material or with free The formation oi ester as has been stated is probably due to a chemical reaction between the alcohols formed and the unhydrogenated fatty material.

Catalysts suitable for carrying out the hydrogenation reactions which yield the novel mixtures of alcohols may consist of any suitable hydrogenation metal or metallic oxide. For example, I may use such reduced metals as copper, tin, cadmium or lead, and in certain cases iron or nickel. Good results are obtained with fused reduced copper oxide alone, which ordinarily comprises a mixture of reduced metal and metallic oxide, or the catalyst may be promoted with such well known' oxide promoters as manganese oxide, zinc oxide, magnesium oxide or chromium oxide. Certain of the ides having both hydrogenating and dehydrog-:.r.ating propensities may be employed, such as zinc oxide, manganese oxide, and cerium oxide, these oxides belonging to the class known as difficulty reducible oxides. These are suitable when used alone or combined with each other, or with other oxides, such as oxides of chromium, molybdenum, tungsten or titanium. In particular, I prefer to use a chromate or chromite of a hydrogenating metal or a mixture of several of the same. Apreferred catalyst containing a single hydrogenating metal may be prepared according to the general methods described in U. S. Patents 1,746,782 and 1,746,783.

cobalt and nickel.

The catalyst described in Example 1 represents that class of catalysts which I have found to be for example, prepare a mixture of copper chromate and zinc chromate and ignite the mixture at a red heat, that is to say, a temperature of 600 C. or above, in order to drive off oxygen and form a mixture of copper oxide, zinc oxide, copper chromite and zinc chromite,

A more convenient method consists of co-precipitating multiple chromates of the reducible and non-reducible oxides with ammonium chromate whereby double ammonium chromates are formed which decompose spontaneously and exothermically when heated to about 400 C.

By difiicultly reducible oxides, I refer to those which remain substantially in the oxide form after several hours exposure in a pure state to the action of hydrogen at 400 C. Reducible oxides under the same conditions are readily converted to the elementary metal and water vapor. Suitable hydrogenating metals whose oxides are readily reducible are silver, cadmium, copper, lead mercury, tin, bismuth, indium, iron, Hydrogenatingv metals whose oxides are difllcultly reducible are magnesium, zinc and manganese.

In the foregoing it will be apparent that I have produced higher alcohol mixtures cheaply and in unlimited quantities starting with the naturally occurring fats and oils and without the use of chemical reagents. The novel and useful character of these mixtures has been established, and their wide application in the art is apparent.

The above examples and descriptions are to be taken as illustrative only. Modifications and vs.- riations therefrom which conform with the spirit of the invention are intended to be included within the scope of the claims.

I claim:

1. 'As a new composition of matter, a mixture 2. As a new composition of matter a mixture containing essentially'alcohols corresponding in number of carbon atoms to the acid radicals contained in cottonseed oil.

WILBUR A. I..AZIER.