| 摘要 |
PURPOSE:To produce formaldehyde in high yield and catalytic activity, without producing water, by dehydrogenating methanol in the presence of a highly selective copper catalyst supported on silica gel. CONSTITUTION:An aqueous solution or organic solvent solution of a copper salt such as copper acetate, copper oxalate, copper oxalate, copper nitrate, etc. is added to a silica gel calcined at a high temperature (about 600-900 deg.C) to impregnate 0.1-6.7wt% copper to the calcined silica gel. The impregnated copper is heated at 200-500 deg.C in an inert gas to effect the decomposition of the copper salt and to obtain a copper catalyst supported on the silica gel. Formaldehyde is produced by the dehydrogenation of methanol in the presence of the above copper catalyst at 400-650 deg.C, preferably 450-550 deg.C. The methanol conversion is 6-36%, the formaldehyde selectivity is 75-85% and the water- content of the product is 0.5-2 wt%. A high catalytic activity can be attained by reducing the copper catalyst with hydrogen at a temperature equal tot he decomposition temperature after the decomposition of the copper salt. |
