| abstract |
1499245 Hydroxycarboxylic acids and derivatives PPG INDUSTRIES Inc 22 April 1976 [23 April 1975] 16284/76 Heading C2C Hydroxycarboxylic acids and their derivatives, e.g. α-hydroxyalkanoic acids, alkyl esters thereof and α-acyloxy derivatives of alkanoic acid, of formula where R is alkyl, alkylene or hydrogen, R<SP>1</SP> is hydroxy or alkoxy, R<SP>2</SP> is hydroxy or acyloxy, provided at least one of R<SP>1</SP> or R<SP>2</SP> is hydroxyl, are prepared by reacting a mixture of carbon monoxide and aliphatic aldehyde together with water or carboxylic acid or alkanol in liquid reaction medium at above 25‹ C., at superatmospheric pressure in the presence of a solid, insoluble particulate acidic catalyst with a hydrogen ion-exchange capacity in excess of 0À1 milliequivalents per gram, and mechanically separating the reaction medium from the catalyst. Strong acid type cation-exchange resins in hydrogen form, or natural or synthetic clays and zeolites may be used as the catalyst and may be separated by decantation, flotation, filtration or centrifugation methods. Examples describe the preparation of acetoxyacetic acid with a variety of catalysts. |