Low temperature aminolysis of methyl stearate catalyzed by sodium methoxide
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Aminolysis of methyl stearate by both primary and secondary amine catalyzed by sodium methoxide was found to be rapid at 30°C. under anhydrous conditions. With primary amines under optimum conditions (mole ratio to ester: amine, 10; catalyst, 0.12), the minimum reaction times necessary to obtain yields of amide over 90% were:n-butylamine, 30 min.;iso-butyl-, 1 hour; allyl-, 1.8 hr.; benzyl-, 3.2 hr.;sec-butyl-, 16 hr.; ammonia (a heterogenous reaction requiring an optimum triethylamine to ester ratio of 2 ml./g. and a catalyst mole ratio of 0.20) 2 days. Secondary amines reacted rapidly at 30°C. (15 min. to 24 hr. for a 90% yield of amide) when the nitrogen atom was joined into a saturated ring or held at least one methyl group, but very slowly even at 100°C, when the substituent was dialkyl larger than methyl. Uncatalyzed, all reactions were extremely slow.
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