Study On Synthesis And Technology Of Methyl 2-(3-oxo-2-pentylcyclopentyl) Acetate

Methyl 2-(3-oxo-2-pentylcyclopentyl) acetate is an important synthetic perfume and organic intermediate because of its stability and unique properties. In this dissertation, the methyl 2-(3-oxo-2-pentylcyclopentyl) acetate was effectively synthesized in a total yield of 58.4% with n-valeraldehyde and cyclopentanone as starting materials through aldol condensation, isomerization, Michael addition and selective decarboxylation processes. Some technological parameters for the process were discussed in detail towards industrialization.Three catalytic systems involving inorganic bases, Lewis acids, modified hydrotalcite silicates were used for selective synthesizing 2-pentylidene-cyclopentanone via aldol condensation reaction. It was found that 80.8% yield in a good selectivity of 90.8% 2-pentylidene-cyclopentanone was achieved when using base-catalytic system, and a poor selection indicated a serious self-condensation of n-valeraldehyde when the Lewis acid catalytic system was employed. With modified hydrotalcite silicates as catalysts, the conversion of n-valeraldehyde in reaction could be improved to 90.2% in a selectivity of 90.8% 2-pentylidene-cyclopentanone, since the catalysts of acid-base active sites were helpful for cross-condensation between n-valeraldehyde and cyclopentanone.2-Pentyl-2-cyclopent-l-one in 96.1% of yield could be achieved via isomerization of 2-pentylidene-cyclopentanone under n-butanol medium in the presence of 5 mol/L hydrochloric acid catalyst during 7 h reflux periods, and further react with dimethyl malonate at-5℃for 12 h to form 3-dimethylmalonyl-2-pentylcyclopent-1-one in 79.6 yield in the presence of sodium methoxide catalyst. In the procedure of selective decarboxylation to synthesize methyl 2-(3-oxo-2-pentylcyclopentyl) acetate, a high yield of 94.5% was obtained under optimal conditions, and mechanism for the reaction was also discussed.