Patent GB-391113-A (GB)
Title: Improvements in the manufacture and production of unsaturated ketones
IPC: C07C49/203
Filed: 1931-10-08
Abstract: Unsaturated ketones are prepared by passing the vapours of aliphatic unsaturated monocarboxylic acids or volatile derivatives thereof over heated decarboxylation catalysts.  When volatile saturated aliphatic, cycloaliphatic or aromatic carboxylic acids or their volatile derivatives are also present, mixed ketones are obtained.  Volatile derivatives are the anhydrides, esters and halides.  Unsaturated monocarboxylic acid substances specified are acrylic, crotonic, undecylenic, oleic and linoleic acids and their methyl, ethyl, propyl, butyl, glycol and glycerol esters; also the acids of vegetable or animal oils and fats which contain 12-20 carbon atoms and their derivatives.  As decarboxylation catalysts, the oxides and phosphates of calcium, barium, strontium, manganese, chromium, titanium, zinc, aluminium and thorium are mentioned, together with metallic iron, copper, cobalt and nickel and their alloys.  The temperatures employed vary between 300 DEG  and 500 DEG  C. and pressures below atmospheric are advantageous in some cases.  An inert gas or vapour may be present.  The ketone products may, if desired, be reduced to secondary alcohols by catalytic hydrogenation or with the aid of sodium, or of magnesium and aluminium activated by small amounts of iodine or mercury.  According to the examples, (1) di-heptadecenyl-ketone is obtained by passing oleic acid at reduced pressure over a manganese oxide catalyst prepared by leading formic acid vapour over manganese carbonate mounted on pumice and heated to 400-425 DEG  C.; catalytic hydrogenation of the product under pressure produces di-heptadecyl-carbinol; by adding the vapours of saturated naphthenic acids in about equimolecular proportions to those of oleic acid, a mixture of unsymmetrical ketones is produced; (2) a mixture of oleic acid (1 mol.) and acetic acid (2 mols.), or of olive oil and acetic acid, is vaporized and passed over calcium oxide under reduced pressure yielding heptadecenyl-methyl-ketone, from which by catalytic reduction heptadecyl-methyl-carbinol is obtained; (3) heptadecenyl-methyl-ketone is also prepared by conducting an equimolecular mixture of oleic acid and acetyl chloride under reduced pressure over heated bauxite; (4) replacement of the oleic acid in (2) by linoleic acid leads to the formation of heptadecenedienyl-methyl-ketone; instead of linoleic acid, the mixtures of acids of soya bean, train, cottonseed and linseed oils may be used, or the oils themselves or other volatile derivatives; (5) a mixture of heptadecenyl-methyl-ketone with oleone results when the vapours of oleic acid and acetic anhydride are passed under reduced pressure over manganese oxide; (6) the vapours of acetic acid and of sperm oil acids diluted with carbon dioxide are led over a catalyst prepared by heating pumice soaked in manganese nitrate solution; a mixture of the methyl ketones of the initial fatty acids is formed; (7) heptadecenyl-phenyl-ketone is prepared by passing the vapours of oleic and benzoic acids under reduced pressure over a catalyst prepared by spreading powdered manganese carbonate on copper grains and moistening with waterglass solution; (8) pumice is soaked in manganese nitrate and heated until all nitrous fumes have escaped and a mixture of acetic acid and soya bean oil conducted over it in the vapour phase under reduced pressure; a mixture of ketones is obtained which is fractionally distilled.  The production of heptadecenyl-propyl-ketone from oleic acid and butyric acid, octylene-methyl-ketone from nonylenic and acetic acids, and decylene-ethyl-ketone from undecylenic and propionic acids, is also mentioned.  Specification 343,098 is referred to.ALSO:Decarboxylation catalysts for the production of unsaturated ketones from the corresponding acids in the vapour phase comprise the oxides and phosphates of calcium, barium, strontium, manganese, chromium, titanium, zinc, aluminium and thorium, or metallic iron, cobalt, copper, nickel and their alloys.  The following catalyst preparations are included in the examples: (1) manganese carbonate mounted on pumice is heated to 400-425 DEG  C. and formic acid vapour is passed over, whereby the carbonate is converted into the oxide; (2) pumice soaked in manganese nitrate is heated until the evolution of nitrous gases ceases; (3) powdered manganese carbonate is spread on copper grains and moistened with waterglass solution.