Patent GB-440154-A (GB)
Title: Process for the conversion of unsaturated oxy compounds to aldehydes, ketones or substituted derivatives thereof
IPC: C07C45/51
Filed: 1935-04-12
Abstract: Unsaturated alcohols and unsaturated non-vinylic ethers and esters are converted into aldehydes, ketones, or substituted derivatives thereof, e.g. ketols and aldols, by heating with an acid acting catalyst in a liquid system which, in the conversion of alcohols, consists of an aqueous or anhydrous organic solvent for the catalyst and, in the conversion of ethers and esters, contains water and, if desired, an organic solvent.  The preferred unsaturated compounds such as alcohols, glycols and halohydrins are represented <FORM:0440154/IV/1> the loose bonds being taken up by hydrogen halogen, hydroxyl, alkyl, alkoxy, carbocyclic, heterocyclic, aralkyl, aralkoxy and other groups.  Unsaturated alcohols with an unsaturated tertiary carbon atom are particularly adaptable.  In converting alcohols having no unsaturated tertiary carbon atom, the use of anhydrous p  carboxylic acid as the solvent is excluded since such use results in esterification of the alcohol.  The reaction product is generally a saturated aldehyde or ketone isomeric with the alcohol.  A g -halogen or g -hydroxyl substituted alcohol, ether or ester, however, yields an unsaturated aldehyde or ketone.  As organic solvents alcohols or cyclic hydroxy compounds may be used, or liquid organic acids preferably containing from 2--5 carbon atoms.  Any suitable acid, acid salt or acid reacting substance can be employed e.g. strong mineral acids or their constituents, or acid salts of polyvalent acids, or organic esters, salts and compounds. Preferably, when unsaturated alcohols are treated under anhydrous conditions, sulphuric acid up to about 0,5 per cent of the weight of alcohol dissolved in acetic, propionic, isobutyric or like acid is used.  With ethers and esters 10--15 per cent aqueous solutions of H2SO4 may be employed. The formation of a second liquid phase during reaction may be prevented by evaporation of the aldehyde or ketone as soon as it separates.  A distilling or fractionating apparatus may be connected with the reaction vessel and the aldehyde or ketone recovered, the other constituents being returned.  The reactant may be admitted continuously to the vessel e.g. by an injector, perforated tube or porous disc.  Heating the reaction mixture at its boiling point at atmospheric pressure generally suffices but higher temperatures and pressures may be used.  In examples: (1) anhydrous sec isopentanol is added to a boiling solution of sulphuric acid in glacial acetic acid in a fractionating still. Methyl isopropyl ketone distils; (2) isobutenol is similarly converted to isobutyraldehyde with a solution of sulphuric acid in isobutyric acid; (3) isobutenol is added to a solution of sulphuric acid in phenol.  The distillate contains isobutyraldehyde and water, and the residue a hard resin which is treated by steam distillation to remove excess phenol.  By adjustment of the reflux substantially all of the carbonyl compound can be combined with the cyclic hydroxy compound to form a resin; (4) di-isobutenyl ether is converted to isobutyraldehyde with sulphuric in glacial acetic acid containing some water; (5) di-isobutenyl ether is fed into 13 per cent aqueous H2SO4 in an autoclave fitted with agitating means. The temperature is maintained at about 125 DEG  C. at a pressure of about 20 lbs./sq. in.  The distillate after drying and refractionating yielded isobutyraldehyde and unreacted ether; (6) a 50 per cent by weight aqueous solution of ethyl alcohol containing 10 per cent, calculated on the aqueous solution, of sulphuric acid is heated to 105 DEG  C.  A mixture of 80 per cent isobutenol, 10 per cent di-isobutenyl ether and 10 per cent water is pumped in while isobutyraldehyde is withdrawn from the still head as an azeotrope with water at a corresponding rate.  The distillate stratifies and the non-aqueous phase is dried and refractionated to give isobutyraldehyde; (7) isobutenyl acetate is similarly converted using a mixture of water, sulphuric acid and acetic acid at 125 DEG  C.; (8) g -chlor-isobutenol is treated with a boiling solution of sulphuric acid in isobutyric acid to give methyl acrolein. Specification 411,741 is referred to.