Calcium phosphate catalyst prodn. for decomposition of 1,3-dioxane(s) - by pptn. of calcium phosphate in presence of ammonia,then steaming in presence of conditioning agent

摘要

Ca phosphate catalyst is prepd. by reacting a water soluble Ca salt with a water-soluble phosphate in NH4OH; recovering the ppt., shaping and drying; and firing at 450-600 deg.C in steam contg. H3PO4 or an org. cpd. (I) or H3PO4 and air or (I) and an inert gas. (I) is an aldehyde, an alcohol, a diene or an O-contg. heterocyclic. The reaction between the Ca salt and phosphate is NH4OH is carried out at a mole ratio of 1.5:1 if no H2PO4 treatment is used; or 1.5-5:1 if the reaction mixt. is treated with an H3PO4 soln. to pH 5.0-7.0, pref. 5.5-6.0. Used esp. for conversion of 4,4-dimethyl-1,3-dioxane into isoprene. It can also be used for dehydration of alcohols. Catalyst has high activity and high selectivity; it also has a long service life and low coking tendency.