| 摘要 |
Glycols and glycerol are produced by reacting hydrogen with an alditol (e.g. sorbitol, mannitol or xylitol) in aq. soln. using a catalyst contg. 85-100 wt.% Cu and 0-15 wt.% of Al, Co, Cr, Zn and/or Mo. Pref. the catalyst contains 85-99% Cu, 1-10% Co, Cr, Zn and/or Mo and 0-10% Al. ADVANTAGE - The catalyst allows continuous operation in a catalytic reactor configuration with entrained bed using a hydrogen partial pressure relatively lower than used in prior art processes for an equal productivity. In an example, a 2 kg Raney alloy (50% Cu- 50% Al) was added in 100 g portions every 2 mins. to 100 l of a 40 wt.% NaOH soln. After 40 mins. addn. was complete, but reaction was continued for a further 2-3 hrs. at 60 deg.C. The obtd. catalyst contd. 99% Cu, had a particle size of 20-80 micrometres, a BET surface area of 20 m2/g and a porous vol. of 0.4 cm3/g. An aq. soln. contg. 10% sorbitol and 27 g of the above catalyst per l was treated at neutral pH with hydrogen (40 bars) at 220 deg.C. After 60 mins. reaction conversion was 72.7% and after 2 hrs. 90.4%. Yields were (w.r.t. sorbitol) 29.3% pentitols, 41.2% glycerol, 10.5% propylene glycol 1,2; 5.1% butanediol-1,2; 5.9% ethylene glycol and 1.7% propanol-1 + butanol-1. |
