Abstract: The method of the invention for continuously producing 2,5-dihydrofuran includes subjecting cis-2-butene-1,4-diol to liquid-phase dehydration-cyclization reaction in the presence of alumina, characterized in that the sum of the concentration of carbonyl compounds present in the reaction system and the concentration of acetal compounds present in the reaction system is controlled to fall within a range of 0.1 to 2 mol/L, provided that the concentration of the acetal compounds is calculated in terms of acetal groups, the concentrations being determined on the basis of the total amount of the reaction mixture. According to the method, 2,5-dihydrofuran, which is useful as a raw material or intermediate for producing pharmaceuticals, agrochemicals, raw materials of polymers, etc., can be continuously produced. The method can prevent inactivation of ?-alumina and is advantageous for long-term production on an industrial scale.

Abstract: The method of the invention for continuously producing 2,5-dihydrofuran includes subjecting cis-2-butene-1,4-diol to liquid-phase dehydration-cyclization reaction in the presence of alumina, characterized in that the sum of the concentration of carbonyl compounds present in the reaction system and the concentration of acetal compounds present in the reaction system is controlled to fall within a range of 0.1 to 2 mol/L, provided that the concentration of the acetal compounds is calculated in terms of acetal groups, the concentrations being determined on the basis of the total amount of the reaction mixture. According to the method, 2,5-dihydrofuran, which is useful as a raw material or intermediate for producing pharmaceuticals, agrochemicals, raw materials of polymers, etc., can be continuously produced. The method can prevent inactivation of ?-alumina and is advantageous for long-term production on an industrial scale.

Abstract: An aminoalcohol is synthesized by reacting a cyclic hemiacetal expressed by Formula 1 (where n is 0 or 1; R1 and R2 are each a hydrogen atom, a monovalent saturated hydrocarbon group which is optionally substituted, or a monovalent aromatic group which is optionally substituted, or R1 and R2 are bonded together into a divalent saturated hydrocarbon group which is optionally substituted; and R3, R4, and R5 are each a hydrogen atom, a monovalent saturated hydrocarbon group which is optionally substituted, or a monovalent aromatic group which is optionally substituted), with hydrogen and any one of ammonia, a primary amine and secondary amine in the presence of a hydrogenation catalyst.

Abstract: A process for producing diamines by reacting a dialdehyde with ammonia and hydrogen in the presence of a hydrogenation catalyst to produce the corresponding diamine, where a solvent comprising an alcohol is used in the reaction and the concentration of water in the reaction mixture is 5 to 15% by weight.