| 摘要 |
Propylene glycol monoalkylether esters of formula R<1>-O-CH2-CH(Me)-O-C(O)-R<2> (I) are new, where R<1> = ethyl or propyl; and R<2> = methyl or ethyl. (I) are prepd. by reacting a propylene glycol monoalkyl ether (II) with acetic acid or propionic acid at above 80 deg C in the presence of an acid catalyst and an azeotropic agent to cause esterification with formation of the crude (I), followed by sepn. of the unreacted acid and water by distn. to yield (I) of high purity. Pref. the mol. ratio (II)/organic acid is 0.6-3.0, the acid catalyst is chosen from H2SO4, p-toluenesulphonic acid and methanesulphonic acid, and the azeotropic agent is chosen from benzene, toluene, xylene and cyclohexane, used in an amt. of 6-30 vol.% w.r.t. the sum of the vol. of (II) and the organic acid.
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