| 摘要 |
PURPOSE:To effectively prepare the subject compound in good selectivity and yield in a simple operation in a short time without requiring large amounts of a catalyst and a solvent by subjecting 3-methoxyisobutyric acid methyl ester to a methanol-removing reaction in the presence of zeolite as a catalyst in a gaseous phase. CONSTITUTION:Methyl 3-methoxyisobutyrate is preferably diluted with a gas such as N2 and subjected to a catalytic methanol-removing reaction in the presence of zeolite catalyst at 160-450 deg.C, preferably 200-350 deg.C, under the ordinary pressure or a slightly increased pressure in a gaseous phase to prepare the objective compound stably for a long time. As the zeolite catalyst, a catalyst having a SiO2/Al2O3 mol ratio of 2-20 is preferable on the performance of the catalyst and a catalyst having a pKa value of -5.6 to +6.8 as an acid strength is employed. The zeolite catalyst is readily prepared by a combination of a conventional ion exchange method and a calcination condition and the calcination of the catalyst at a temperature not decomposing the structure of the zeolite crystals with the flow of air permits the perfect recovery of the catalytic activity for the regeneration and reemployment of the catalyst. |
