PROCESS FOR PRODUCTION OF MANNIT0L WITH STEREOSELECTIVE CATALYTIC HYDROGENATION ON RANEY-COPPER CATALYSTS

摘要

Marmitol is prepd. by stereoselective catalytic hydrogenation, in the presence of a Raney-copper catalyst. A typical alloy used for the prepn. of the catalyst contains 2-060% Raney copper, 80-40% aluminium, and 0.1-15 cobalt and/or Zn, Fe, Cr, B and Pt as promoters. The catalysts is prepd., by dissolving at 20-100 deg. C., the aluminium by 3-20 vol.wt sodium-hydroxide in the presence of 1-10% sodium tetraborate, and/or 1-10% polyalcohol, carbohydrate, (glucose, fructose, xylose, sorbitol, mannitol, saccharose). The catalyst is then rinsed to neutrality by water, and a soln. of fructose or a mixt. of glucose and fructose is hydrogenated on its surface at 40-110 deg. C and 10-100 bars pressure, in the presence of 0.001-5 wt.% chloride, and/or bromide and/or iodide cpds. or borate ions. Halogen cpds. are present as Li, Na or K salts, and as salts of prim. sec. or tert. aliphatic amines. Borate ions are present as borax. When borax is present, the pH of the mixt. to be hydrogenated is adjusted to 4-8. When the hydrogenating starting mix contains both glucose and fructose, 2-5 wt.% glucose isomerising enzyme is added to the reactor mix, on a silica substrate(Dwg.0/0)