反应详情

A 1000 ml. four-necked flask fitted with overhead stirrer, nitrogen sparge tube, thermometer and Barrett trap on top of a 6" steam jacketed Vigreux column was charged with 134.2 g. trimethylolpropane (1.0 mol), 580.6 g. methyl acetoacetate (5.0 mols), 0.8 g. triphenyl phosphite and 0.8 g. dibutyltin oxide. Steam was turned on in the jacketed Vigreux and the mixture was stirred with a nitrogen sparge and heated. When the pot temperature reached 142° C. methanol began distilling rapidly from the mixture. Heating was continued for a total of 50 minutes to a maximum pot temperature of 185° C. Vacuum was then applied and the excess methyl acetoacetate was removed first at 20 mm. Hg then at 1 mm. Hg with a maximum pot temperature of 180° C. Yield of orange liquid product was 372.4 g., 96% of theory. A small amount of white solid formed in the sides of the flask after cooling to room temperature. This was removed by gravity filtration. Proton NMR showed 100% conversion based on integration of methylene adjacent to esterified oxygen relative to methyl of trimethylolpropane.

1. customfour-necked flask fitted with overhead stirrer
2. customnitrogen sparge tube
3. additionwas charged with 134.2 g
4. customsparge
5. temperatureheated
6. customreached 142° C.
7. distillationbegan distilling rapidly from the mixture
8. temperatureHeating
9. customwas continued for a total of 50 minutes to a maximum pot temperature of 185° C
10. customthe excess methyl acetoacetate was removed first at 20 mm. Hg
11. customwith a maximum pot temperature of 180° C
12. customA small amount of white solid formed in the sides of the flask
13. customThis was removed by gravity filtration