Prepn. of sorbitol - by hydrogenation of alpha-D-glucose in aq. soln. on unsupported metal catalyst of iron gp.

摘要

Sorbitol (D-glucitol) is prepd. from alpha-D-glucose in aq. soln. by continuous hydrogenation at H2 pressure of 150-500 bars and 60-120 deg.C., in a fixed bed process in a reaction zone, using as catalyst carrier-free bodies of elements of the Fe gp., with pressure strength of more than 50 N (100-400 N) on the surface of the body, and an internal surface of 10-90 square m/g. USE/ADVANTAGE - Conversion of glucose is almost complete, and epimerisation, breakage of the C chain, and formation of higher mol. components by condensation and formation of ethers, are avoided. Sorbitol is obtd. in quantitative yield, with above 99% purity, and contg. less than 0.3% of mannitol and less than 0.2% of unconverted glucose; no purificn. is needed. The catalyst is not transferred, in ionic or colloidal form, to the soln. phase of the substrate, which does not become contaminated with heavy metals. The catalysts can easily be processed after use. Sorbitol is a replacement for sugar for diabetics and in low-calory sweeteners. It is less cariogenic than glucose or other sugars.