Title:
Process for producing alcohols from hydroxy carboxylic compounds
United States Patent 2094611


Abstract:
This invention relates to catalytic processes for the production of organic compounds of an alcoholic character. More particularly it relates to a process for the catalytic reduction by means of elementary hydrogen of hydroxy-carboxylic acids, their esters, and their anhydrides to the corresponding...



Inventors:
Lazier, Wilbur A.
Application Number:
US75707134A
Publication Date:
10/05/1937
Filing Date:
12/11/1934
Assignee:
Pont DU.
Primary Class:
Other Classes:
568/864
International Classes:
C07C29/149
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Description:

This invention relates to catalytic processes for the production of organic compounds of an alcoholic character. More particularly it relates to a process for the catalytic reduction by means of elementary hydrogen of hydroxy-carboxylic acids, their esters, and their anhydrides to the corresponding glycols.' Specifically, the invention relates to the use of certain catalysts especially well suited to the hydrogenation of hydroxy acids and their derivatives to the corresponding glycols, and to processes for the production of octadecanediol from castor oil and its derivatives.

This application is a continuation-in-part of my co-pending application Serial No. 584,576, which was filed January 2, 1932, as a continuation-in-part of applications Serial Nos. 520,473 and 520,474, both filed March 5, 1931. Application Serial No. 520,474 has since matured into U. S. Patent 1,839,974. The present application is also a continuation-in-part of the following co-pending applications: Serial No. 629,754 filed August 20, 1932, which in turn was a continuation-in-part of Serial No. 445,224 filed April 17, 1930; Serial No. 584,574 filed January 2, 1932; and Serial No. 715,509 filed March 14, 1934.

For many years the only known methods for the reduction of hydroxy-carboxylic acids, esters, and their anhydrides to the corresponding glycols were purely chemical reactions involving the consumption of expensive reducing agents.

The most successful procedure was that outlined by Bouveault and Blanc (Chem. Zentr. 1904, II, 184; 1905, II, 1700). This process involves preparing an ester of the acid to be reduced and the use of metallic sodium and absolute alcohol as the reducing agent. Thus it has been possible to prepare alcoholic derivatives of the simple aliphatic carboxylic acids. This method, however, is so costly as to render its use prohibitive for the manufacture of various glycols which might. otherwise be very useful in the arts.

By suitable modifications of processes fully described in the co-pending specifications to which reference has already been made, it has now become possible to realize on a commercial scale a technically and economically successful catalytic hydrogenation of hydroxy acids, their esters, and their anhydrides, whereby glycols are formed which correspond in the number of carbon atoms to the acids or acid derivatives subjected to the hydrogenation treatment. Other products such as the corresponding saturated hydrocarbons and esters of the newly formed glycols may also be prepared in this way by minor variations in the procedure, but the invention is primarily concerned with the production of glycols which are the intermediate products between the esters of the glycols and the corresponding hydrocarbons resulting from exhaustive hydrogenation.

In my co-pending application Serial No. 520,473, filed March 5, 1931, there is contained a description of the successful hydrogenation of natural glyceryl esters known as fats and fatty oils, and there is specifically described in Example 4 the hydrogenation of castor oil. The hydrogenation process therein described effects the hydrogenation of the ester group of the glyceride, thereby yielding alcohols. This type of hydrogenation is to be distinguished sharply from the process of hardening fats by hydrogenation as practiced at a much earlier date, and which consists in agitating a glyceride of an unsaturated fatty acid with a suspended nickel t catalyst in the presence of gaseous hydrogen under a pressure slightly in excess of atmospheric pressure. In the process of hydrogenating fats and fatty oils as practiced in the prior art, the temperatures employed are usually 50° to 23 150° C. and are never greater than 200° C., while the pressures customarily used are substantially atmospheric.

This invention has as an object to provide a process for the conversion of hydroxy-carboxylic ,acids, their esters, and their anhydrides to the corresponding glycols. It is a further object of the invention to disclose processes for the hydrogenation of castor oil, ricinoleic acid, hydroxystearic acid, and derivatives of the same, and the ;products produced by such hydrogenation. A more specific object is the preparation of octadecanediol which is a new compound.

The processes of my invention are characterized by the use of an excess of hydrogen and ternm- . peratures and pressures much in excess of those ordinarily employed. In general, the invention is carried out by bringing the hydroxyrcarboxylic compound and hydrogen into intimate contact with a suitable alcohol-forming catalyst at relatively high temperatures and pressures. There are, however, several modifications of the general process. For example, a mixture of the compound to be hydrogenated, solid catalyst, and gaseous hydrogen may be brought together at high temperatures and pressures with suitable agitation in a closed autoclave capable of withstanding the necessary pressure. -In this case the catalyst is preferably a composition containing copper, either in the elementary form or combined with oxygen as a lower oxide. Other hydrogenating metal oxides may be employed in conjunction with copper, or suitable catalyst supports such as kieselguhr, silica gel, and activated carbon may be used. In another modification, of the process the hydroxy-carboxyllc compounds and hydrogen are passed under high pressures and elevated temperatures over mixed hydrogenation catalysts containing substantial quantities of difficultly reducible oxides of hydrogenating metals prepared in a suitable granular form and held in place in a pressure-resisting tube. Contrary to expectation, it has been found that under high hydrogen pressures, hydroxy acids and their derivatives are much less susceptible to decomposition by heat than would be supposed from their behavior when heated in air. Under reducing conditions and in the presence of a suitable catalyst the decomposition, if such it may be termed, takes place in a controlled manner and with the absorption of hydrogen and the production of the corresponding dihydric alcohols.

The following examples are illustrative of some of the methods that may be employed in the practice of my invention: Example I A hydrogenation catalyst is prepared as fol30 lows: 23 g. of cadmium nitrate, 24 g. of copper nitrate and 245 g. of zinc nitrate are dissolved in 500 cc. of water and mixed at ordinary temperature with an equal volume of water containing 126 g. of ammonium bichromate and 75 cc. of 28% ammonium hydroxide. After stirring, the mixture is exactly neutralized with additional ammonium hydroxide and allowed to settle.

After several washes by decantation, the precipitate is dried, ignited at 400° C. and compressed into tablets or grains suitable for use in catalytic gas apparatus.

Twenty-five cc. of the mixed chromite catalyst prepared as described above was loaded into an alloy steel reaction vessel capable of being heated and withstanding high pressures. The tube was fitted with a preheater, a pump for injecting liquid ester at a constant rate, a Tconnection for introducing hydrogen under pressure, a suitable condenser and trap for separating liquid products, and exit control valve. Ethyl ricinoleate was passed with hydrogen over the catalyst at a rate of about 200 cc. per hour. The average pressure was 2570 pounds per square inch, the average temperature 3700 C., and the rate of hydrogen flow 7.7 cubic feet per hour.

The saponification value of the condensed product indicated a conversion to alcohols amounting to about 65%. In order to remove the remaining olefinic unsaturation, the products were subjected to a further hydrogenation with a nickel catalyst in the liquid phase at 1000 C. After distilling off the ethyl alcohol there remained a white solid material consisting of about equal parts of octadecanediol and stearyl alcohol, together with a lesser amount of the esters of these alcohols.

Example II Castor oil maintained under 2700 pounds per square inch hydrogen pressure was passed at a temperature of 400° C., together with hydrogen, at a space velocity of 4 volumes of oil per volume of catalyst per hour and at a molecular ratio of 12 moles of hydrogen per mole of combined ricinoleic acid over 25 cc. of the zinc-copper-cadmium 76 chromite catalyst describe' in Example I. The decrease in saponification value was about 60%, while the iodine number was lowered from 65 to 55. The product was quite fluid and possessed a pleasant alcoholic odor. By further hydrogenation with nickel in the liquid phase by the prior art method, namely, at a temperature of 500 to 150* C., and at a pressure slightly in excess of atmospheric pressure, the product was readily converted to a white solid material, containing a large proportion of a dihydric alcohol. The crude product had an acid number of 3, a saponification number of 80, an Iodine number of 4, and an acetyl number of 171.

The following procedure was used to separate out the octadecanediol from the crude mixture; One thousand grams of the white solid material was saponified by refluxing for 8 hours with a solution of 70 g. of sodium hydroxide dissolved in 2.5 liters of water. The soapy mass was evaporated and dried. The residue was broken up and continuously extracted with ether in small batches. The various portions of ether extract were combined, and the ether distilled off. The residue was washed with hot water and dried.

Four hundred thirty-one grams of product was obtained, of which 376 g. was fractionated through a 15 inch lagged Vigreux column at 0.1 mm. pressure, (gauge reading) with the following results: Fraction oint Bath temp. fraction P. No. 1--------- 40-113 C. 1765 C. 24.0g. Liq. .... 2-....... 120-157 200-206 10.5 Pasty . 3--------. 157-161 205-215 175.5 51-53° C. - 18 4----.......---.. 167-178 225-235 13.0 48-50 --.------ 178-182 230-235 117.0 68-60 263 Residue--------- -------........... 31.0 Pasty ... Fraction 5 was refractionated at 0.5 mm., the first 10 g. of distillate being discarded. The remainder distilled at 180* to 182° C., with the bath temperature at 2250 to 235° C. The latter part of the distillate melted at 66° to 67° C., and was quite pure octadecanediol-1,12.

Analysis: Calculated for C1isH3aO: C, 75.52; 45 H, 13.29.

Found: C, 75.66, 75.65; H, 12,96, 13.26.

Octadecanediol is a white solid melting at 66° to 67" C., and boiling at 180* to 1820 C. at a pressure of 0.5 mm. The glycol has an acetyl 0 number corresponding to a dihydric alcohol. It contains one primary and one secondary alcohol group. The compound appears to be crystalline but is very waxy in character. It dissolves in alcohol or ether. It is not readily soluble in 55 water but may be emulsified at temperatures above the melting point.

Example III A good commercial grade of ricinoleic acid pro- 60 duced by saponification of castor oil was hydrogenated continuously to produce high yields of glycol. The zinc-copper-cadmium chromite catalyst described in Example I was heated to a temperature of about 380° C. The acid was pumped 65 over 100 cc. of the catalyst at the rate of about 200 cc. per hour. The hydrogen pressure was 2500 to 3000 pounds per square inch, and the rate of flow of the hydrogen about 15 cubic feet per hour. Under these conditions the ricinoleic acid 70 is hydrogenated in the vapor phase. There was produced a viscous product containing about 40% of esters and practically no free acid, the remainder being, with the exception of a small amount of glycerol, practically all long-chain higher al- 7 cohols. -The reaction products were susceptible of further hydrogenation and purification in the same manner as described in Example II to pro... duce-actadecanediol.

Example IV Four hundred twenty-eight grams of copper nitrate and 176 grams of chromic acid were dissolved in 2760 cc. of water and 88 g. of anhydrous 10 aimonia was added to the solution with agitation during a period of 15 to 30 minutes. The precipitate was filtered, washed once on the filter and dried, after which it was ignited at 500° C.

The resulting copper chromite powder was extracted twice by stirring it for 15 minutes each time with a solution of 200 g. of glacial acetic acid in 1800 cc. of water. After extraction, it was washed free from acid, filtered, dried and screened through a 20 mesh screen. Two hundred seventy-five grams of this catalyst and 4330 g. of ethyl hydroxystearate were placed in an autoclave and hydrogen was introduced to a pressure of 3000 pounds per square inch. The mixture was then heated to 350° C. and agitated for 9 hours, after which hydrogen absorption had ceased. The decrease in saponification number of the ester during this treatment corresponded to 95% hydrogenation of the carboxyl groups while recovery and separation of the product yielded 12% stearyl alcohol and 80% octadecanediol.

Example V Twenty-six grams of barium nitrate and 218 35 g. of cupric nitrate were dissolved in 0.8 liter of 3water by heating to 700 C. A solution of 128 g. of ammonium bichromate and 0.15 liter of 28% ammonium hydroxide in 600 cc. of water was added with stirring. The precipitate was filtered; dried and ignited at 4000 C. The ignition residue was then extracted twice with 10% acetic acid, washed and dried. Twenty grams of this copper barium chromite was agitated with 340 g. of ethyl alpha-hydroxy isobutyrate under a hydrogen pressure of 2500 pounds per square inch. Hydrogen absorption was rapid at about 200° C. and the reaction was complete in about one hour. On distillation of the product, there was obtained a 91% yield of 2-methyl propane diol-1,2.

50 Example VI One hundred fifty grams of ethyl citrate and 12 g. of the copper barium chromite catalyst prepared as described in Example V were charged into a steel reaction tube built to withstand high pressure. The tube was agitated for 4.5 hours at a temperature of 2400 C. and a hydrogenation pressure of 600 atmospheres. From the reaction product there was isolated 25 g. of a trihydric alcohol (trimethylol propane) and an oily residue 6O containing a substantial quantity of a cyclic ether alcohol, the constitution of which was not fully determined.

Example VII 65 Fifteen hundred grams of copper nitrate dissolved in 4 liters of water was mixed with a solution containing 1000 g. of ammonium chromate in an equal volume of water. Ammonium hydroxide was added to neutralize the acidity de70 veloped during precipitation of the copper ammonium chromate. The precipitate was washed by decantation, filtered, and dried, after which it was ignited at a temperature of 400° C. The ignition residue was then extracted twice with 75 10% acetic acid, washed and dried.

Two hundred grams of gamma hydroxy valeric ester was subjected to hydrogenation in the presence of 25 g. of copper chromite catalyst prepared as described above. The mixture was agitated and heated to 265' C. for 3 hours under a hydrogen pressure of 2500 pounds per square inch.

When the hydrogen absorption had run its course, the products were separated from the catalyst and analyzed by fractional distillation. Besides pentanediol-1,4 there was formed appreciable amounts of methyl tetrahydro furane.

Example VIII Three hundred and twenty grams of a copperbarium-chromite catalyst prepared as described 15 in Example V and 4000 grams of 12-hydroxy stearin (hardened castor oil) were placed in a stirring autoclave and hydrogen was introduced to a pressure of 3000 pounds per square inch which was maintained throughout the run. The mixture was then heated to 260* C. and agitated for seven hours, after which hydrogen absorption had ceased. After removal of the products from the autoclave and filtering, the alcohols thus obtained solidified to a hard solid having a melting point of about 65° C. The decrease in saponification number of the oil during hydrogenation corresponded to a 92% conversion of the carboxyl groups, while the hydroxyl value of 347 obtained by analysis of the product indicated a substantially complete conversion of the hydroxy stearin to the corresponding octadecanediol-1,12.

Example IX Sixteen grams of a copper chromite catalyst 35 prepared as described in Example IV, 0.4 g. of magnesium oxide, and 200 g. of ethyl hydroxystearate were charged into a steel reaction tube built to withstand high pressures. Hydrogen was introduced to 3000 pounds pressure per square inch and maintained while agitating the tube for 11 hours at 260* C., after which hydrogen absorption had ceased. The decrease in saponification value of the oil during hydrogenation corresponded to a 98% conversion of the carboxyl group, while the hydroxyl value of 302 obtained by analysis of the product, indicated approximately 87% conversion of ethyl hydroxystearate to the corresponding octadecanediol-1,12.

Example X Copper carbonate was prepared by dissolving 720 g. of copper nitrate trihydrate in 1 liter of water and heating the solution to 40° C. and slowly adding with agitation during a period of one 55 hour a solution consisting of 300 g. of sodium carbonate dissolved in 3 liters of water. The precipitate thus formed was washed four times by -decantation using 5 liters of distilled water for each wash, after which it was filtered, dried at 60 110° C., and ground to a fine powder. An intimate mixture consisting of 25% of copper carbonate prepared as described and 75% of copper barium chromite prepared as described in Example V was made by grinding the two com- 65 ponents in a mortar. Sixteen grams of the above catalyst mixture and 200 g. of castor oil were heated in a steel reaction tube to a temperature of 260° C. under a hydrogen pressure of 3000 pounds per square inch with continuous agitation 70 for a period of 12 hours, during which time a reduction in saponification value of the oil occurred equivalent to 99% conversion of the carboxyl group while the iodine number was reduced to less than 1.0. The hydroxyl value of the prod- 75 uct was 322, equivalent to approximately 92% conversion to octadecanediol-1,12.

Although certain definite conditions of operation such as temperature, pressure and time of contact of the material treated with the catalyst have been indicated in the above examples, it will be apparent that these factors may be varied within wide limits within the scope of my invention. The catalytic reduction of hydroxy acids, their esters, and their anhydrides to alcohols or glycols requires the use of temperatures and pressures appreciably higher than customarily employed for other hydrogenation reactions. The temperature may range from above 200* C. up to 500* C. The preferred temperature range is 240* to 400* C., depending somewhat on the catalystcomposition selected and the method used for carrying out a given reaction. The success of the process also depends on the use of elevated pressures in excess of 10 atmospheres, while the preferred pressure is 50 to 400 atmospheres. The maximum pressure which can be used is limited only by the strength of the reaction apparatus.

Whereas the critical factors and inventive steps in the hydrogenation of hydroxy-carboxylic compounds to glycols are the use of high temperatures and pressures, it necessarily follows that suitable catalysts may be selected from among a number of different hydrogenating metals and oxides. Mild-acting hydrogenating catalysts such as metallic copper and zinc oxide which are well known to be suitable for the synthesis .of methanol from carbon monoxide and hydrogen are in general also suitable catalysts for the production of glycols. On the other hand, there are certain very energetic catalysts such as metallic nickel and iron which are known to catalyze the formation of hydrocarbons from oxides of carbon and hydrogen. These ferrous metal catalysts, when employed in the hydrogenation of hydroxy acids and their esters, tend to carry the reaction too far with the formation of hydrocarbons.

Therefore, if the hydrogenation is to be operated for the production of alcohols and glycols to the substantial exclusion of hydrocarbons, it is preferable to select as the catalyst a composition comprising a member of the group of non-ferrous hydrogenating metals such as copper, tin, silver, cadmium, zinc, lead, their oxides and chromites, and oxides and chromites of manganese, and magnesium. Especially good results are obtained with finely divided copper oxide, either wholly or partially reduced and preferably supported upon an inert surface-extending material such as kieselguhr, or promoted by such oxide promoters as manganese oxide, zinc oxide, magnesium oxide, or chromium oxide. The above mentioned mild-acting catalysts may be termed the alco-. hol-forming catalysts to distinguish them from the more energetic hydrocarbon-forming elements of the platinum and ferrous metal groups.

Elementary nickel, cobalt, and iron, when suitably supported on kieselguhr, may be used to effect the reduction of carboxylic compounds with hydrogen, but in these cases the product contains besides alcoholic bodies a preponderance of hydrocarbons, and this disadvantage in most cases will prove so serious as to preclude the use of these catalysts unless the hydrocarbons themselves are the desired end products.

Catalysts suitable for use in the liquid phase batch method of hydrogenation are preferably prepared in a powder form. The preferred catalyst for this purpose is usually a copper chromite prepared by igniting a double copper ammonium chromate to its spontaneous decomposition temperature as described in U. S. Patent 1,746,783. Many modifications of this procedure have been practiced involving the use of acid extraction, hydrogen reduction, and the use of a supplementary support such as kieselguhr, but these are modifications in degree only. The essential feature is the use of copper oxide intimately associated or combined with chromium sesquioxide and the chromite method of preparation is a convenient method for effecting the desired association. The method, however, is not limited to copper but may be practiced in the preparation also of zinc chromite, silver chromite, manganese chromite, etc. For use in the continuous flow method of hydrogenation certain metal oxides belonging to the class of difficultly reducible hydrogenating oxides may be conveniently employed on account of their rugged character and the ease with which they may be shaped into hard granules for loading into stationary apparatus. By the term "difficultly reducible" is meant that the oxides are not substantially reduced to metal by prolonged exposure in a state of purity to the action of hydrogen at atmospheric pressure and at a temperature of 4000 to 450° C. Such oxides suitable for use as catalysts in the hydrogenation of hydroxy-carboxylic compounds are zinc oxide, manganese oxide, and magnesium oxide. These oxides may be employed either alone or in combination with each other or with other metals or oxides which have a promoting action.

Preferably the difficultly reducible hydrogenating oxides also are prepared in the form of chromites as already indicated in the examples.

Hydroxy acids and their derivatives are particularly susceptible to partial dehydration, and it has been found that this undesirable side reaction may be largely prevented by employing a mild inorganic base added to the hydrogenation catalyst. For example, products having much higher hydroxyl values are obtained if a little magnesia, zinc oxide, lime, or barium hydrate is added to the catalyst or to the reaction system. Preferably the alkali earth buffer is incorporated into the catalyst at the time of its precipitation.

In carrying out the hydrogenation of hydroxycarboxylic compounds in a continuous reaction system, the rate at which the ester may be pumped over the catalyst with satisfactory results is a function of the catalytic activity and also of the molecular weight of the ester. An active hydrogenating catalyst will ordinarily convert eight times its volume of ester per hour.

Higher rates of flow of the ester may be employed at the expense of slightly lower conversion.

The processes of the present invention are ap- 6, plicable to a large number of hydroxy-carboxylic acids, their esters and anhydrides, for example, lactic, ricinoleic, hydroxy-butyric and -isobutyric, hydroxy-valeric, hydroxy-stearic acids, etc. - As indicated, these acids may be employed for hydrogenation in the form of the free acid or as their esters or anhydrides. The same glycols are obtained on hydrogenation irrespective of the form in which the hydroxy-carboxylic compound is treated. The ester may be a mono-alkyl ester or an ester of a polyhydric alcohol such as glycerol. The hydroxy acid may be unsaturated as in the case of ricinoleic acid or fully saturated as in the case of hydroxy-stearic acid. The hydrogenation of these acids and their derivatives lead to a very interesting new glycol, i. e., octadecanediol-1,12.

Castor oil is a glyceride of ricinoleic acid, and complete or partial reduction of the carboncarbon unsaturation may occur as in the usual hydrogenation process of the prior art, but in the present process this is only incidental to the more important reaction of hydrogenation of the ester group which results in the formation of alcohols. As an added step in my invention, I sometimes prefer after conducting the reaction as indicated above to favor alcohol formation, to hydrogenate the reaction products at low pressure and temperature with a nickel catalyst in the usual manner known to the art. This brings all the reaction products up to the same level of hydrogen saturation, yielding new compositions, the most important of which is octadecanediol. Alternatively, the hydrogenation with nickel may precede the carboxylic hydrogenation carried out for the purposes of converting the carboxyl groups to carbinol groups, as, for example, in the conversion of ethyl, ricinoleate to the hydroxy stearate followed by conversion to octadecanediol.

The hydrogenation products obtained by the hydrogenation of castor oil under the conditions of the present invention consist of a mixture of higher alcohols and other products and this mixture in itself constitutes a new composition of matter, which in some instances finds use in the arts without any separation of the product into its components. In such cases, as well as when it is not feasible to separate the alcohols from the other hydrogenation products, the presence of the alcohols and the amount thereof formed may be demonstrated conclusively by determination of the acetyl or hydroxyl values.

Depending on the conditions of hydrogenation, a part of the secondary hydroxyl group of octadecanediol may be split off, giving a monohydric alcohol as one of the products. The method for isolating the glycol disclosed in Example I involves saponification and extraction. A more simple procedure for commercial operation consists in hydrogenating ricinoleic acid or its esters rather completely and separating the glycol produced by direct vacuum fractional distillation of the crude hydrogenated product. The wax residue may then be put through the hydrogenation step again, together with fresh raw material.

From the foregoing it will be apparent that I have developed an economic method for obtaining octadecanediol-1,12 from castor oil, ricinoleic acid, ethyl ricinoleate, ethyl hydroxy stearate, hydroxystearin, etc., without the use of expensive chemical reagents and at a small cost per unit of product. In addition, I have made possible the preparation of novel alcohols and other derivatives from castor oil. Octadecanediol, the new saturated alcohol described above, has many unique properties which make it of value for many industrial applications, whether it be in pure or in crude form. It is suitable for use as a cosmetic base when combined with face creams, especially those of the vanishing type. Its waxy properties may be utilized in paper or other finishes or in furniture, floor or automobile polishes.

It is suitable for use in compounding rubber or in synthetic resins and as a softener for coating compositions. As a component of soap, octadecanediol contributes to detergent power in the presence of hard water and tends to counteract the harshness of soaps. The derivatives of octadecanediol such as ester. thereof find use as sPfteners, for example, in nitrocellulose compositions, and the sulfonated octadecanediol is a valuable wetting-out agent and detergent.

The above examples and descriptions are intended to be illustrative only and not as limiting the scope of the invention. Any modifications or variations thereof which conform to the spirit of the invention are intended to be included within the scope of the claims.

I claim: 1. A process for producing alcohols from hydroxy carboxylic compounds, which comprises bringing hydrogen and a member of the class consisting of the hydroxy carboxylic acids, and their esters into contact with a mild-acting hydrogenation catalyst at a temperature in excess of 200° C. and at a pressure in excess of 10 atmospheres.

2. Process according to claim 1 characterized in that the temperature is maintained between 2000 and 500* C.

3. Process according to claim 1 characterized in that the temperature is maintained between 2400 and 400° C.

4. Process according to claim 1 characterized in that the pressure is maintained between 50 and 400 atmospheres.

5. Process according to claim 1 characterized in that the catalyst is a hydrogenation catalyst of the class consisting of mild acting hydrogenating metals, their oxides and chromites, the oxides and chromites of manganese and magnesium, and mixtures of such metals, oxides and chromites.

6. Process according to claim 1 characterized in that the catalyst is a mild-acting alcoholforming hydrogenation catalyst.

7. Process according to claim 1 characterized in that the catalyst is a catalyst containing copper as an essential ingredient.

8. Process according to claim 1 characterized in that the catalyst comprises essentially a mixed chromite of cadmium, copper and zinc.

9. Process according to claim 1 characterized in that the catalyst comprises essentially a difficultly reducible hydrogenating metal oxide.

10. Process according to claim 1 characterized in that the catalyst comprises essentially a mixture of difficultly reducible hydrogenating metal oxides.

11. Process according to claim 1 characterized in that the catalyst comprises essentially a chromite of a hydrogenating metal.

12. Process according to claim 1 characterized in that the catalyst comprises essentially a mixture of chromites of hydrogenating metals.

13. Process according to claim 1 characterized in that the hydrogen is present in excess.

14. Process according to claim 1 characterized in that the hydrogenated reaction products are go subjected to further hydrogenation to remove the carbon-carbon unsaturation.

15. Process according to claim 1 characterized in that the hydrogenated reaction products are subjected to further hydrogenation under a pressure slightly in excess of atmospheric and at a temperature between 500 and 2000 C. in the presence of a nickel catalyst in order to saturate the carbon-carbon bond, then subjecting the products produced by the second hydrogenation step to separation and purification.

16. A process for producing a glycol, which comprises bringing hydrogen and a hydroxy carboxylic acid into contact with a mild-acting hydrogenation catalyst at a temperature in excess of 2000 C. and at a pressure in excess of 10 atmospheres.

17. Process according to claim 16 characterized in that the catalyst is a hydrogenation catalyst of the class consisting of mild acting hydrogenating metals, their oxides and chromites, the oxides and chromites of manganese and magnesium, and mixtures of such metals, oxides and chromites.

18. Process according to claim 16 characterized in that the catalyst containis a small amount of an alkali earth buffer.

19. Process according to claim 16 characterized in that the catalyst contains as essential ingredients chromites of copper and barium. 20. A process for producing a glycol, which comprises bringing hydrogen and an ester of hydroxy carboxylic acid into contact with a mildacting hydrogenation catalyst, at a temperature in excess of 2000 C. and at a pressure in excess of 10 atmospheres.

21. Process according to claim 20 characterized in that the catalyst is a hydrogenation catalyst of the class consisting of mild acting hydrogenating metals, their oxides and chromites, the oxides and chromites of manganese and magnesium, and mixtures of such metals, oxides and chromites.

22. Process according to claim 20 characterized in that the catalyst contains a small amount of an alkali earth buffer.

23. Process according to claim 20 characterized in that- the catalyst contains as essential ingredients chromites of copper and barium.

24. A process for producing a glycol, which comprises bringing hydrogen and ricinoleic acid into contact with a mild-acting hydrogenation catalyst at a temperature in excess of 2000 C. and at a pressure in excess of 10 atmospheres.

25. The process according to claim 24 characterized in that the catalyst is a difficultly reducible oxide of a hydrogenating metal.

26. The process according to claim 24 characterized in that the catalyst is a mixture of difficultly reducible oxides by hydrogenating metals.

27. The process according to claim 24 characterized in that the catalyst comprises essentially a chromite of a hydrogenating metal.

28. The process according to claim 24 characterized in that the catalyst comprises essentially a mixture of chromites of hydrogenating metals.

29. The process according to claim 24 characterized in that the reaction is carried out in 5the vapor phase and hydrogen is present in excess.

30. The process according to claim 24 characterized in that the reaction is carried out at a temperature between 300° and 4000 C.

31. The process according to claim 24 characterized in that the reaction is carried out at a pressure between 100 and 250 atmospheres.

32. The process according to claim 24 characterized in that the reaction Is carried out at a temperature between 3000 and 400° C. and at a pressure between 100 and 250 atmospheres.

33. A process for producing alcohols from castor oil, which comprises saponifying castor oil to form an acid, passing said acid and hydrogen over a hydrogenation catalyst of the class consisting of mild acting hydrogenating metals, their oxides and chromites, the oxides and chromites of manganese and magnesium, and mixtures of such metals, oxides, and'chromites at a temperature in excess of 200* C. and at a pressure in excess of 10 atmospheres.

34. The process according to claim 33 characterized in that the hydrogenated reaction products are subjected to further hydrogenation to remove the carbon-carbon unsaturation.

35. A process for producing alcohols from castor oil, which comprises saponifying castor oil to form an acid, then passing said acid and hydrogen over a mixture of the chromites of zinc, copper, and cadmium at a temperature of about 3800 C. and at a pressure of about 2500 to 3000 pounds per square inch.

36. A process for producing alcohols from ricinoleyl derivatives which comprises passing ricinoleic acid and hydrogen over a hydrogenation catalyst of the class consisting of mild acting hydrogenating metals, their oxides and chromites, the. oxides and chromites of manganese and magnesium, and mixtures of such metals, oxides and chromites at a temperature in excess of 2000 C. and at a pressure in excess of 10 atmospheres, separating the glycol produced by direct vacuum distillation of the crude hydrogenated product. 37. Process according to claim 24 characterized in that the catalyst is a hydrogenation catalyst of the class consisting of mild acting hydrogenating metals, their oxides and chromites, the oxides and chromites of manganese and magnesium, and mixtures of such metals, oxides and chromites.

38. Process according to claim 24 characterized in that the catalyst contains a small amount of an alkali earth buffer. 39. Process according to claim 24 characterized in that the catalyst contains as essential ingredients chromites of copper and barium.

40. Process according to claim 24 characterized in that the hydrogenated reaction products are subjected to further hydrogenation to remove the carbon-carbon unsaturation and then recovering the octadecanediol formed.

41. Process according to claim 24 characterized in that the hydrogenated reaction products are subjected to further hydrogenation under a pressure slightly in excess of atmospheric and 'at a temperature between 500 and 250° C. in the presence of a nickel catalyst to saturate the carbon-carbon bond, then separating and purifying the octadecanediol formed.

42. A composition containing essentially an alcohol which is obtainable by the hydrogenation of ricinoleic acid, at a temperature in excess of 2000 C. and at a pressure in excess of 10 atmospheres, in the presence of a mild-acting hydrogenation catalyst.

43. A process of producing a glycol which comprises bringing hydrogen and an ester of ricinoleic acid into contact with a mild-acting hydrogenation catalyst at a temperature in excess of 200° C. and at a pressure in excess of 10 atmospheres.

44. The process according to claim 43 characterized in that the catalyst is a difficultly reducible oxide of a hydrogenating metal. 45. The process according to claim 43 characterized in that the catalyst is a mixture of difficultly reducible oxides of hydrogenating metals.

46. The process according to claim 43 characterized in that the catalyst comprises essentially a chromite of a hydrogenating metal.

47. The process according to claim 43 characterized in that the catalyst comprises essentially a mixture of chromites of hydrogenating metals.

48. The process according to claim 43 characterized in that the reaction is carried out in the vapor phase and hydrogen is present in excess.

49. The process according to claim 43 characterized in that the reaction is carried out at a temperature between 300° and 400° C.

50. The process according to claim 43 characterized in that the reaction is carried out at a pressure between 100 and 250 atmospheres.

51. The process according to claim 43 characterized in that the reaction is carried out at a temperature between 300° and 400° C. and at a pressure between 100 and 250 atmospheres.

52. A process for producing alcohols from castor oil, which comprises passing castor oil and hydrogen over a mixture of the chromites of zinc, copper, and cadmium at a temperature of about 300-4000 C. and at a pressure of about 2700 pounds per square inch.

53. A composition containing essentially octadecanediol-l,12.

54. Octadecanediol-1,12.

55. A process for producing a glycol which comprises bringing hydrogen and castor oil into contact with a mild-acting hydrogenation catalyst at a temperature in excess of 2000 C. and at a pressure in excess of 10 atmospheres.

56. The process according to claim 55 characterized in that the catalyst is a hydrogenation catalyst of the class consisting of mild acting hydrogenating metals, their oxides and chromites, the oxides and chromites of manganese and magnesium, and mixtures of such metals, oxides and chromites.

57. The process according to claim 55 characterized in that the catalyst contains a small amount of an alkaline earth buffer.

58. The process according to claim 55 characterized in that the catalyst contains as essential ingredients chromites of copper and barium.

59. The process according to claim 55 characterized in that the hydrogenated reaction products are subjected to further hydrogenation to remove the carbon-carbon unsaturation and then recovering the octadecanediol formed.

60. The process according to claim 55 characterized in that the hydrogenated reaction products are subjected to further hydrogenation under a pressure slightly in excess of atmospheric and at a temperature between 50° and 250* C. in the presence of a nickel catalyst to saturate the car- 15 bon-carbon bond, then separating and purifying the octadecanediol formed.

61. A mixture of alcohols obtainable by the carboxyl hydrogenation of castor oil.

62. A mixture of alcohols obtainable by the carboxyl hydrogenation of castor oil followed by the hydrogenation of the resulting product with a nickel catalyst in order to remove the carbon-carbon unsaturation.

63. A mixture of alcohols obtainable by the carboxyl hydrogenation of the mixture of acids obtained by the hydrolysis of castor oil.

64. A mixture of alcohols obtainable by the carboxyl hydrogenation of the mixture of acids obtained by the hydrolysis of castor oil followed by the hydrogenation of the resulting product with a nickel catalyst in order to remove the carbon-carbon unsaturation.

WILBUR A. LAZIER. 35