反应详情

It is clear from experiments E13 to E16 that an increase in the reaction temperature to above 300° C. does not lead to a rise in the yield of shorter-chain polyols, but instead the yield thereof decreases, accompanied by a decreasing conversion of the glucose used. Despite the very short residence time of 5 s, at 250° C. (E13) there is still a sorbitol yield of approximately 42% and a mannitol yield of 6%, whilst approximately 13% polyols from the group propanetriol (glycerin), 1,3-propanediol, 2,3-butanediol and 1,4-butanediol were obtained. At 300° C. (E14) there is a sorbitol/mannitol yield of only 11 or approximately 4%, whereas the yield of the indicated polyols increases to approximately 30%. There is also a maximum ethanediol yield of approximately 17%. With higher temperatures of 350° and 400° C. (E15 and E16), there is a drastic decrease in the yields of all the desired products.