Abstract: A process for producing methyl methacrylate through gas-phase catalytic reaction of methyl .alpha.-hydroxyisobutyrate as the starting raw material which process comprises feeding methanol in an amount by weight of 0.1 to 3.0 times the amount of the methyl .alpha.-hydroxyisobutyrate in a reaction system and proceeding with the gas-phase catalytic reaction in the presence of a catalyst comprising a synthetic faujasite zeolite having a free alkali content of at most 0.1 milliequivalent/g or a catalyst comprising a molded product which is formed by molding a synthetic faujasite zeolite and a clay in an aqueous solution or suspension having a pH of less than 9. According to the above process, it is possible to produce methyl methacrylate in high yield over a long period of time by the use of methyl .alpha.-hydroxyisobutyrate as the starting raw material.

Abstract: A process for preparing a carboxylic acid ester which includes subjecting a carboxylic acid and an alcohol or a phenol to an esterification reaction in the presence of a silica-titania catalyst. The silica-titania catalyst is prepared by adding an acidic solution containing a silicon compound and a titanium compound dissolved therein to a solution of a basic compound to bring about co-precipitation, in which the acidic solution is a nitric acid-acidic solution or a sulfuric acid-acidic solution, a ratio of the amount (gram equivalent) of nitric acid or sulfuric acid to the amount (mol) of the silicon compound in the acidic solution is 0.5 to 50 and the amount of the titanium compound in the acidic solution is such that a ratio of titania (TiO.sub.2) in the silica-titania catalyst is 1 to 50% by weight.

Abstract: A process for preparing a silica-titania catalyst by adding an acidic solution containing a silicon compound such as sodium silicate and a titanium compound such as titanium sulfate dissolved therein to a solution of a compound such as ammonium bicarbonate to bring about co-precipitation, in which the acidic solution is a highly concentrated nitric acid-acidic or sulfuric acid-acidic solution, and a ratio of the dissolved titanium compound in the acidic solution is regulated in a certain range.According to this process, a catalyst capable of exerting a high performance in an esterification reaction and the like can be efficiently obtained.