Preparation of beta -isopropylnaphthalene

摘要

Process of preparing beta -isopropylnaphthalene substantially free of corresponding alpha -isomer, in yields amounting to 90% and more by a continuous two-stage process comprising (1) alkylating naphthalene with propylene at a temperature of about 150 DEG -280 DEG C. under a pressure of 5 to 30 atm in the presence of a phosphoric acid catalyst supported on a SiO2 carrier and using a mol ratio of 1/5 to 1/20 mol propylene to 1 mol naphthalene to isopropylate 45 to 65% of the naphthalene and form a mixture of alpha - and beta -isopropylnaphthalene and then without separating off the unreacted naphthalene, (2) heating the isomeric mixture from stage (1) in the presence of a phosphoric acid catalyst supported on SiO2, to a temperature of 180 DEG -280 DEG C. under an inert gas pressure of 5 to 30 atm until no further beta -isopropylnaphthalene is formed and recovering said beta -isopropylnaphthalene from the isomerization mixture.