Patent GB-635934-A (GB)
Title: Improvements in the production of ketones
IPC: C07C45/00
Filed: 1947-08-18
Abstract: 2 (iii) Ketones are prepared by reacting an aldehyde free of ethylenic or acetylenic bonds and tertiary carbon atoms, and containing only carbon, hydrogen, and oxygen, with a non- hydrocarbon compound having the grouping <FORM:0635934/IV (b)/1> in the presence of free radicals and/or substances capable of yielding them.  The reaction is illustrated by the equation R-CHO+R1CH=C(R11)-CHXY-->RCOCH(R1)-CH(R11)-CHXY, where R is non- tertiary hydrocarbon; R1 is hydrogen, methyl, halomethyl or halogen; R11 is hydrogen, alkyl, aryl, halogen, haloalkyl, or acyloxymethyl; X is either a residue containing oxygen or nitrogen linked to the 2-propenyl radical through said oxygen or nitrogen or is halogen; Y is hydrogen or a residue containing oxygen linked to the 2-propenyl radical through said oxygen; or X and Y together is oxygen.  Halo and halogen represent chlorine or fluorine.  Other 2-propenyl compounds containing other hetero atoms, e.g. silicon, phosphorus, and sulphur, may be used.  Representative alde hydes are acetaldehyde, propionaldehyde, p  butyraldehyde, isobutyraldehyde, heptaldehyde, cyclohexanal, benzaldehyde, and phenylacet aldehyde.  2 - Propenyl compounds include allyl alcohol, allyl, methallyl, and 2-chlor methyl-allyl chlorides, allyl ethyl, allyl fur furyl, allyl octyl, and dimethallyl ethers, diallyl formal, acrolein ethyl acetal, 2-acetoxy methyl-allyl acetate, allyl acetate, allyl ethyl carbonate, allyl caproate, allyl laurate, meth allyl benzoate, crotyl acetate, cinnamyl acetate, 2-chlorallyl butyrate, methallyl carbonate, methallyl ethyl sulphate, N-allyl phthalimide and acetamide, 3-nitropropene-1, allyl triethyl silicate, methallyl dimethyl phosphate, ethyl 2- propenyl-phosphonate, allyl triethyl silane, and methallyl ethyl sulphide.  Sources of free radicals include u-v light and peroxidic com pounds, for example dibenzoyl and diacetyl peroxides, and tert.-butyl hydroperoxide.  The reactants may be heated, in presence or absence of an inert diluent, at temperatures sufficient to decompose the peroxide, generally 0-140 DEG  C., and optionally under elevated pressure.  Prefer ably at least 1 mole, e.g. 2-15 moles of aldehyde per mole of 2-propenyl compound is used or the latter added incrementally to an excess of the aldehyde. Readily polymerizable 2-propenyl compounds may yield appreciable amounts of ketones of the formula <FORM:0635934/IV (b)/2> where n is an integer greater than 1.  The amount of peroxidic compound is normally 1-15 mole. per cent of the 2-propenyl com pound.  In examples: (1) allyl acetate, acet aldehyde and dibenzoyl peroxide are heated at 70 or 90 DEG  C., yielding 3-aceto-propyl acetate, which on chlorination gives the vitamin B1 intermediate, 3-chlor-3-aceto-propyl acetate; (2) n-butyraldehyde similarly yields 3-butyro propyl acetate; (3) acrolein ethyl acetal and n-butyraldehyde give the diethylacetal of 3 - butyro - propionaldehyde; (4) 2 - acetoxy methyl-allyl acetate and n-butyraldehyde yield 2 - acetoxymethyl - 3 - butyro - propyl acetate; (5) and (6) diallyl ether or diallyl formal and n-butyraldehyde yield 3-butyro-propyl allyl or allyloxymethyl ether.