Simultaneous prepn. of max. pure propylene glycol mono-methyl ether (PGMME) and min. di:propylene glycol mono-methyl ether - comprises addn. of isomer mixt. of PGMME and 2-methoxy-1-propanol to PGMME prepn. mixt. obtd. from propylene oxide and methanol

摘要

Simultaneous prepn. of isomer-pure propylene glycol monomethyl ether (I), and dipropylene glycol monomethyl ether (II) using base-catalysed reaction of propylene oxide (PO) and methanol comprises adding an isomer mixt. of 15-55% 1-methoxy-2-propanol (i.e. (I)) and 45-85% 2-methoxy-1-propanol directly to the mixt. obtd. in the prepn. of (I) such that the mol. ratio PO:MeOH:isomer mixt. is 1:3.5-7.5:0.5-2 (pref. 1:5-6:1.2-1.6). 30-70% of the catalyst is made up of catalyst recyclate, with the catalyst concn. being 0.0005-0.05 (pref. 0.005-0.02)mol/l. The reaction is conducted at a pressure of 1.0-2.0 (pref. 1.4-1.6) Mpa and the temp. held at 120-200 (pref. 160-180) [deg]C.