Abstract: The alkyl substances of diethyl methylmalonate is an synthetic intermediate which is widely used in the production of food additives and spicery. Food flavouring agent of 2 - methyl - 2 - sec-butyl malonate intermediate was synthesized starting from 2-methyl malonate and 2-bromo-butane via the processes of alkylation reaction under catalysis of sodium alcohol. Based on the affecting factors including the ratio of the raw materials，the reaction time，the reaction temperature and the catalyst investigated, the synthesis conditions and technology were optimizated by response surface methodology. The product was prepared in average yield 70.6% ( SD =±0.11), and the structure was confirmed with GC and NMR. The process has potential industrial application with milder reaction conditions and lower costs.

Key words: 2-methyl-2-sec-butyl malonate, synthesis optimization, alkylation reaction, response surface methodology