FORFARANDE FOR FRAMSTELLNING AV RENT MONOMETYLTEREFTALAT FOR POLYESTERFIBERFRAMSTELLNING

摘要

1385561 Preparation of monomethyl terephthalate DYNAMIT NOBEL AG 2 June 1972 [4 June 1971] 25878/72 Heading C2C The invention comprises a method of preparing monomethyl-terephthalate which comprises (a) oxidizing p-xylene in the presence of a polyvalent heavy metal catalyst at 90-140‹ C. and a pressure of 1-15 atmospheres and under an oxygen partial pressure of <3 atmos., stopping the oxidation when a maximum achievable selectivity for p-toluio acid is reached; (b) esterifying the resulting acid to methyl-p-toluate; (c) oxidizing the methyl-p-toluate to monomethyl terephthalate in the presence of a heavy metal polyvalent catalyst at 130-200‹ C. and 1-6 atmospheres, stopping the oxidation when maximum achievable selectivity for monomethyl terephthalate is reached; (d) purifying the resulting monomethyl terephthalate. The preferred polyvalent catalyst is a polyvalent cobalt salt.