| 摘要 |
<p>1496926 Polyhydric alcohols ICI UNITED STATES Inc 19 Aug 1975 [20 Aug 1974 5 Nov 1974] 34429/75 Heading C2C A polyhydric alcohol is produced by contacting a carbohydrate in an aqueous medium at pH 3 or above with hydrogen at elevated temperature and pressure in the presence of a catalyst comprising metallic ruthenium supported on an aluminosilicate zeolite having a silica/alumina ratio of at least 3. The carbohydrate may be a monosaccharide or a polysaccharide, preferably readily hydrolysable. The zeolite is preferably of type Y; the ruthenium may be introduced by ion exchange, and may be reduced to the metal with hydrogen; alternatively, reduction to the metal may occur during the process. The catalyst preferably contains nor more than 1% alkali metal when the starting material is a polysaccharide. A temperature of 100-200‹ C. and a pressure of at least 100 p.s.i.g. is suitable; when the starting material contains polysaccharide reaction is preferably carried out in two stages, the first at 100-175‹ C. and the second at 170-200‹ C., at a pH of 3-4À5. Used catalyst may be regenerated by washing with dilute aqueous mineral acid as claimed in Specification 1,496,927. The process is exemplified by the conversion of corn starch hydrolysate and of glucose to sorbitol and of invert sugar to a product containing mannitol.</p> |
