GB715744A - Improvements in or relating to the production of aldehydes and acetals - Google Patents

Abstract

Bis-acetals are prepared by reacting an acetal of an olefinically unsaturated mono-aldehyde with carbon monoxide and hydrogen, in the presence of a cobalt catalyst and at elevated temperature and super-atmospheric pressure, whereby an aldehyde group is introduced at the double bond so forming a mono-acetal of a di-aldehyde, thereafter and without isolation of the mono-acetal reacting the product or a part thereof containing the mono-acetal with a mono- or di-hydric alcohol to convert the mono-acetal to a bis-acetal and subjecting the reacted product or part thereof to fractional distillation for the recovery of the bis-acetal. The acetal used as starting material may be of the type <FORM:0715744/IV (b)/1> according to their derivation from aldehydes R1.CHO and mono-alcohols R2OH and R3OH or dihydric alcohols R4(OH)2. In a modification, a mono-acetal is prepared following the same procedure but using, as starting material, a mono-olefinically unsaturated compound other than an aldehyde or acetal of an aldehyde, such unsaturated reactant preferably having a functional group in the molecule, e.g. unsaturated alcohols such as allyl alcohols and crotyl alcohol; unsaturated acids such as acrylic acid, methacrylic, crotonic acid and oleic acid; unsaturated esters such as ethyl and methyl acrylates and methacrylates, allyl acetate, tetrahydro-benzyl acetate, tetrahydro-benzyltetrahydro benzoate and methyl oleate, and unsaturated ketones and nitriles. The Oxosynthesis reaction is preferably effected at 100-180 DEG C. and 50-250 atmospheres pressure and in the presence of an inert solvent such as gasoline fractions, low molecular weight paraffin fractions, cyclohexane, methyl cyclohexane or benzene. Suitable Oxo synthesis catalysts are cobalt basic carbonates, cobalt naphthenates, cobalt salts of fatty acids, cobalt carbonyls and a supported catalyst of cobalt, thoria and magnesia on kieselguhr. Acetalization of the Oxo product may be effected with mono- or di-hydric alcohols including C1-4 saturated aliphatic monohydric alcohols, C2-4 glycols and hydroxy cyclo paraffins; the water formed may be removed continuously by refluxing the reacting mixture in presence of a solvent which may be that used in the Oxo synthesis or one added subsequently, e.g. hydrocarbons, halogenated hydrocarbons and ethers. The bis-acetals may be hydrolysed to the corresponding di-aldehydes. In acid solution, the bis-acetals react as the di-aldehydes and the bis-acetal of succindialdehyde may thus be converted into the oxime of the aldehyde or oxidized by hydrogen peroxide to succinic acid. In examples (1) acrolein is refluxed with 1 : 3-butylene glycol in cyclohexane solution using ammonium chloride as catalyst and the acetal 2 - vinyl - 4 - methyl - 1 : 3 - dioxane isolated, subjected to the Oxo synthesis in cyclohexane solution, the crude product refluxed with 1 : 3-butylene glycol as above and then fractionated yielding bis-(1 : 3-butylene glycol) acetal and minor amounts of unchanged acrolein acetal and propionaldehyde acetal; (2) crotonaldehyde is converted into its bis-(1 : 3-butylene glycol) acetal with some butylene glycol acetal of n-butyraldehyde, and tetrahydrobenzaldehyde into cyclohexane dialdehyde bis-(1 : 3-butylene glycol) acetal via the cyclic acetal of the monoaldehyde as in (1); (3) acrolein is likewise converted into the bis-(2 : 3 butylene glycol) acetal. Tetrahydrobenzaldehyde may also be reacted upon in the form of its acetal with ethylene glycol. Specifications 702,191, 702,192, 702,195, 702,196, 702,197, 702,201, 702,203, 702,204 and 702,206 are referred to.