Patent GB-356731-A (GB)
Title: Improvements in the catalytic hydrogenation of esters of aliphatic carboxylic acids
IPC: C07C29/149
Filed: 1930-03-01
Abstract: Aliphatic and cycloaliphatic mono- and polycarboxylic acids containing more than five carbon atoms or derivatives thereof are heated in the vapour or liquid phase in the presence of hydrogen-containing gases and an activated hydrogenation catalyst at a temperature below the decomposition temperature of the initial material.  The products comprise alcohols containing the same number of carbon atoms as the original acid or acid component, together with esters formed by their condensation with part of the acidic starting material.  Hydrogenation catalysts mentioned are the base metals, copper, nickel, iron, cobalt, silver or mixtures thereof, prepared before or during the process from their salts, oxides or other compounds such as carboxylic acids.  The necessary activation of these catalysts may be effected by fine disintegration, by deposition on carriers such as fibrous asbestos, powdered graphite, silica gel or inert metal powders, or by adding known activating materials.  The latter may comprise compounds of solid elements of groups 1-7, e.g. hydroxides, oxides, carbonates, phosphates, silicates, nitrates, cyanides and iron-cyanides of potassium, sodium, calcium, barium, magnesium, lanthanum, thorium, cerium, zirconium, boron, chromium, molybdenum, tungsten, uranium, manganese, vanadium or titanium; such of the foregoing metals as form acids with oxygen may appear in the anion, in which case the catalyst may be, for instance, copper, nickel, cobalt, iron, silver or zinc vanadate, molybdate, manganate, uranate or tungstate; solid metals of groups 2-4, e.g. zinc, cadmium, tin and aluminium, may also be employed in the free state.  The alcoholic products may be esterified with long-chain carboxylic acids such as montanic acid for the formation of synthetic waxes, or with low-molecular carboxylic acids such as acetic acid to produce esters which are useful as assistant solvents, swelling or gelatinizing agents in the manufacture of lacquers and varnishes.  When the process is operated in the liquid phase, wax-like esters are often formed which can be used as substitutes for beeswax or spermaceti or as assistants in the preparation of polishes.  Catalysts mentioned in the examples are prepared by (1) mixing copper chromate with colloidal silicic acid, drying and reducing with hydrogen; (2) reducing cobalt carbonate with hydrogen to give a pyrophorous powder; (3) reducing cobalt carbonate containing a little potassium nitrite with hydrogen; (4) adding vanadic acid to metallic cobalt; (5) reducing a mixture of cobalt nitrate, copper nitrate and potassium bicarbonate with hydrogen; (6) reducing cobalt carbonate and aluminium oxide; (7) reducing nickel nitrate or kieselguhr, stirring with potassium bichromate, drying and further treating with hydrogen; (8) mixing nickel with chromium; (9) reducing cobalt carbonate containing some potassium hydroxide.ALSO:Aliphatic and cycloaliphatic mono- and polycarboxylic acids containing more than five carbon atoms, or derivatives such as their salts, esters, anhydrides, halides or amides, are heated in the vapour or liquid phase in the presence of hydrogen-containing gases and an activated hydrogenation catalyst at a temperature below the decomposition temperature of the initial material until the saponification value or acid value has considerably diminished and substantial quantities of saturated alcohols containing the same number of carbon atoms as the original acid or acid component are formed.  The reaction is preferably effected under pressure, though atmospheric pressure only is sufficient in certain cases.  Hydrogenation catalysts mentioned are the base metals, copper, nickel, iron, cobalt, silver or mixtures thereof, prepared before or during the process from their salts, oxides or other compounds such as carboxylic acids.  The necessary activation of these catalysts may be effected by fine disintegration, by deposition on carriers such as fibrous asbestos, powdered graphite, silica gel, or inert metal powders, or by adding known activating materials.  The latter may comprise compounds of solid metallic elements of Groups 1 to 7, e.g. hydroxides, oxides, carbonates, phosphates, silicates, nitrates, cyanides and iron-cyanides of potassium, sodium, calcium, barium, magnesium, lanthanum, thorium, cerium, zirconium, boron, chromium, molybdenum, tungsten, uranium, manganese, vanadium or titanium; such of the foregoing metals as form acids with oxygen may appear in the anion, in which case the catalyst may be, for instance, copper, nickel, cobalt, iron, silver or zinc vanadate, molybdate, manganate, uranate or tungstate; solid metals of Groups 2-4, e.g. zinc, cadmium, tin and aluminium, may also be employed in the free state.  The hydrogen is usually employed in excess and may be diluted with inert gases or vapours such as nitrogen, carbon dioxide, water or alcohol. Aldehydes are first formed and these become converted into alcohols and subsequently into hydrocarbons.  The conditions are so chosen that alcohols preponderate in the product, strong working conditions being avoided in order that no cracking may take place.  The alcohols formed may combine with part of the acidic starting material to produce esters.  Starting materials containing double linkages or nitro groups simultaneously have the linkages saturated and nitro groups reduced.  The alcoholic products may be employed for softening natural or synthetic rubber or guttapercha; they may be esterified with long-chain carboxylic acids such as montanic acid for the formation of synthetic waxes, or with low-molecular carboxylic acids such as acetic acid to produce esters which are useful as assistant solvents, swelling or gelatinizing agents in the manufacture of lacquers and varnishes; they may also be sulphonated to produce washing, emulsifying and wetting agents which can be used even in acid baths or with hard water.  When working in the liquid phase, wax-like esters are often formed which can be used as substitutes for beeswax or spermaceti, as dressing or impregnating agents for textiles or as assistants in the preparation of polishes.  According to the examples, (1) oleic acid acid ethyl ester, prepared by heating train oil with ethyl alcohol, is led with hydrogen at 290  DEG C. over a catalyst prepared by mixing copper chromate with colloidal silicic acid, drying and reducing with hydrogen, whereby octodecyl alcohol is obtained; if the temperature be raised to 350 DEG  C., the product is partially converted into octodecylene; (2) a mixture of alcohols is obtained by heating the mixed carboxylic acids, resulting from the destructive oxidation of paraffin wax by means of nitrogen dioxide, with hydrogen in the presence of pyrophorous cobalt powder, obtained by reducing cobalt carbonate with hydrogen; (3) a mixture of palmitic and stearic anhydrides is treated with hydrogen in the presence of a catalyst prepared by reducing cobalt carbonate containing a little potassium nitrite with hydrogen and gives a mixture of alcohols corresponding to the anhydrides; (4) stearic acid is reduced to octodecyl alcohol using metallic cobalt activated by the addition of vanadic acid as catalyst; some stearic acid octodecyl ester which is formed may be further transformed; a similar procedure is employed for the treatment of colophony, linoleic acid, montanic acid, naphthenic acids, acids from the oxidation of paraffin wax, ammonium stearate, stearic acid amide and methylamide; (5) octodecyl alcohol is obtained by the reduction of stearic acid methyl ester using a catalyst prepared by treating a mixture of cobalt nitrate, copper nitrate and potassium bicarbonate with hydrogen; (6) the treatment of olive oil at 230 DEG  C. and 200 atmospheres in the presence of a reduced mixture of cobalt carbonate and aluminium oxide gives octodecanol; an increase of the temperature to 275 DEG  C. results in the formation of some octodecane, whilst by reducing the pressure to 150 atmospheres a wax is obtained; coconut fat and natural waxes such as beeswax or carnauba wax may be similarly converted into alcohols; (7) soya bean oil is converted into a mixture of octodecanol and its stearic ester using a catalyst prepared by reducing nickel nitrite on kieselguhr, stirring with potassium bichromate, drying and further treating with hydrogen; similar products are obtained from train oil and rape seed oil; (8) hydroxyoctodecyl alcohol is prepared from castor oil using a catalyst made by reducing cobalt carbonate containing a little potassium nitrite with hydrogen; (9) lauric acid amide yields a product of the formula C12H35.NH.CHOH.C11H23 using the catalyst of the preceding example; (10) adipic acid gives a mixture of 1 : 6-dihydroxyhexane and hexyl alcohol in the presence of reduced powdered cobalt carbonate; (11) montan wax, bleached according to the process of Specification 305,552, [Class 2 (iii), Dyes &c.], is esterified with methyl alcohol and heated with hydrogen using a nickel-kieselguhr catalyst and forms a pale hard wax; (12) montanic acid also forms a hard wax in the presence of a mixture of nickel and chromium; (13) lauric anhydride gives dodecanol using a catalyst prepared by reducing cobalt carbonate containing some potassium hydroxide.  The first example is effected in the vapour phase at ordinary pressure, whilst in the remainder elevated pressure, usually of the order of 200 atmospheres, is employed.  Specifications 286,201, 290,319, 299,373, 306,471, 309,024, 314,035, 339,048, [all in Class 2 (iii), Dyes &c.], 340,107, and 342,670 also are referred to.ALSO:Saturated alcohols, prepared by the catalytic hydrogenation of aliphatic and cycloaliphatic mono-and poly-carboxylic acids containing more than five carbon atoms and their derivatives, are useful as softening agents for natural rubber and guttapercha.