Aldoses such as glucose solution are catalytically hydrogenated in a multiple-stage fixed-bed reaction process to produce glycerol and other polyol products. The feedstream pH to each reactor is controlled to between about 7 and 14 by adding an alkaline promotor material such as calcium hydroxide. First-stage reaction zone conditions are 130.degree.-180.degree. C. temperature, 500-2000 psig hydrogen partial pressure, and feedstream liquid space velocity is within range of 0.5-3.5 V.sub.f /Hr/V.sub.c. The first reactor uses a high activity nickel catalyst to produce at least about 98 W % conversion to alditol such as sorbitol solution. The resulting alditols such as 15-40 W % sorbitol solution in water is catalytically hydrocracked in a second-stage fixed-bed reaction zone preferably using a high-activity nickel catalyst to produce at least about 30 W % conversion to glycerol and glycols products. Second-stage reaction zone conditions are 420.degree.-520.degree. F. temperature, 1200-2000 psig hydrogen partial pressure, and liquid hourly space velocity of 1.5 to 3.0. The reaction products are separated in a recovery step, and unconverted heavy alditol feed can be diluted and recycled to the second-stage reaction zone for further hydrogenolysis to produce 40-90 W % glycerol product. Sorbitol conversion is maintained preferably at between about 30-70 W % and a purge stream containing unconverted sugars is passed to a third-stage catalytic reaction zone for further conversion to alditols and polyols.
葡萄糖等醛糖在多级固定床反应过程中进行催化加氢,产生
甘油和其他多元醇产品。通过添加碱性
促进剂如
氢氧化钙,控制每个反应器的进料pH在7至14之间。第一阶段反应区条件为130℃至180℃温度,500至2000 psig
氢气分压,进料液体空间速度在0.5至3.5 Vf / Hr / Vc范围内。第一反应器使用高活性
镍催化剂,产生至少98W%的醇糖转化率,如
山梨醇溶液。所得到的醇糖,如15-40W%的
山梨醇溶液在
水中,通过第二级固定床反应区进行催化加氢,优选使用高活性
镍催化剂,产生至少30W%的
甘油和
乙二醇产品的转化率。第二阶段反应区条件为420℃至520℃温度,1200至2000 psig
氢气分压,液体小时空间速度为1.5至3.0。反应产物在回收步骤中分离,未转化的重醇糖进料可以稀释并循环到第二级反应区进行进一步的氢解,产生40-90W%的
甘油产品。优选地,
山梨醇转化保持在30-70W%之间,并将含有未转化糖的净化流通过第三级催化反应区进行进一步转化为醇糖和多元醇。