The composition of the raw materials of this embodiment: 560 g of methyl acrylate, 716 g of methanol, 2.24 g of cobalt oxide, 8.96 g of indium oxide, and 17.6 g of concentrated sulfuric acid; method of preparation: methyl acrylate, methanol, and a synthesis catalyst (cobalt oxide and indium oxide) were added into a reactor, and the temperature of the reaction solution was maintained at 50 °C with sufficient stirring. Nitrogen and oxygen were charged into the reactor, and the partial pressure of nitrogen and oxygen was controlled to be 0.4 MPa to start the reaction. The reaction lasted for 16 hours. The reaction was judged to be complete when the content of methyl acrylate in the reaction solution decreased to 3%, followed by the addition of etherified reaction product. The catalyst was recovered by filtration, and petroleum ether was added to the filtrate, which was homogeneously stirred and left to stratify. The upper layer was petroleum ether layer, and the petroleum ether was recovered by distillation at atmospheric pressure to obtain the intermediate 3,3-dimethoxypropanoic acid methyl ester 703 g. Methanol and methyl acrylate were recovered from the lower aqueous phase. Methyl 3,3-dimethoxypropionate was transferred to a cracking kettle and 17.6 g of concentrated sulfuric acid was slowly added and the temperature was raised to 190 °C for 20 h of cracking reaction. All the cracking products were collected to obtain 430 g of crude methyl 3-methoxyacrylate (MAME). The crude MAME was placed in a distillation vessel and the product was purified by vacuum distillation, resulting in 478 g of the target product, methyl 3-methoxyacrylate. In this embodiment, the yield based on methyl acrylate was 82.4% and the purity of the product was 95.8%.
