Verfahren zur Herstellung von 1,3-Dimethyl-5-isopropylbenzol

摘要

1286296 1,3 - Dimethyl - 5 - isopropylbenzene DEUTSCHE TEXACO AG 3 Dec 1969 [5 Dec 1968] 18328/72 Divided out of 1286295 Heading C5E 1,3 - Dimethyl - 5 - isopropylbenzene is produced by (i) contacting a xylene component and dimethyl diisopropylbenzene in a molar ratio of 1À8-3 moles xylene per mole tetraalkylbenzene at 45-55‹ C. in the presence of a Friedel-Craft catalyst for 7-12 hours and (ii) reacting the reaction mixture with 0À85-1À05 moles propylene per mole reaction mixture at 45-85‹ C. for 50-80 minutes, the xylene component consisting mainly of m-xylene whilst the o-xylene if present forms not more than 2 wt. per cent of the xylene component. A preferred reactant is 68 wt. per cent m-xylene and 32 wt. per cent p-xylene. The catalyst may be AlCl 3 used in amount 0À1-2 wt. per cent of the xylene. The product may be separated into the desired first fraction and a second fraction of dimethyl diisopropylbenzenes which may be recycled for contact with xylene in step (i).