Patent GB-736682-A (GB)
Title: Process for the treatment of mixtures comprising oxygen-containing organic compounds
IPC: C07C29/74
Filed: 1952-02-01
Abstract: Mixtures having a high content of oxygen-containing organic compounds (particularly of products obtained by the catalytic hydrogenation of carbon monoxide or by the catalytic addition of carbon monoxide and hydrogen to olefines) including esters having boiling points above and below 130 DEG  C. are separated into two streams one which contains more than 50, preferably more than 80, per cent of compounds boiling above 130 DEG  C. and another which contains more than 50 per cent of compounds boiling below 130 DEG  C., and each stream is separately saponified and neutralized, the higher boiling stream being treated mainly in the liquid phase and the lower boiling stream mainly in the vapour or gaseous phase. Liquid phase treatment may be effected under synthesis pressures and at about 140-150 DEG  C. with caustic solution in counter-current to yield water-soluble salts of fatty acids which are withdrawn and an overhead consisting of hydrocarbons, aldehydes, alcohols and ketones.  The gaseous phase treatment is effected in a similar way at about 100-150 DEG  C. and under synthesis pressures, preferably 10-20 atmospheres to yield water-soluble alcohols, aldehydes and ketones which are withdrawn together with fatty acid salts and an overhead which contains hydrocarbons, alcohols, unreacted carbon monoxide and hydrogen, carbon dioxide, methane and nitrogen, the constituents being recovered in the usual way and synthetis gases recycled.  The oily products of the latter treatment may be continuously after-treated with caustic in a third stage.  Aqueous solutions of hydroxides or carbonates of alkali metals or alkaline earth metal compounds generally in concentrations of 2-50, preferably 5-20, per cent are used for saponification and neutralization.  Alcoholic solutions may be used for saponifications in the gaseous phase and for the treatment of products from this stage.  The fatty acids may be obtained from their salts on treatment with sulphuric acid.  In the isolation of products by extractive processes alcohols or ketones containing 3-5 C atoms per molecule with up to 5 per cent of water are advantageous extraction agents.  The alcohols in the overhead from the liquid phase treatment may be converted into acetals, c.f. Specification 705,601, and so separated from the hydrocarbons.  Other extractants for the liquid products from the liquid phase treatment are methanol and its homologues, glycol and its homologues and mixtures of monodi- and tri-hydric alcohols. In an example a primary product from an Oxo synthesis is separated into streams boiling above and below 150 DEG  C., subsequent liquid phase treatment being effected in counter-current with 15 per cent caustic soda solution to obtain, on isolation from the overhead, alcohols and hydrocarbons with small amounts of aldehydes and ketones the alcohols being separated by acetalization with propionaldehyde and extraction with propanol, gaseous phase treatment is also effected in counter-current with 15 per cent caustic soda solution, the alcohols and small quantities of aldehydes and ketones being extracted with methanol from the upper oil phase after conventional separation and recycling operations. A diagrammatic representation of suitable apparatus is provided.