NOVELTY - A 2-butene-1,4-diol is prepared by hydrogenating 2-butyne-1,4-diol in the presence of a structured catalyst and in the absence of a solvent. USE - For preparing 2-butene-2,4-diol that is an important industrial intermediate in the preparation of vitamin B6, pharmaceuticals, and insecticides. ADVANTAGE - The 2-butene-1,4-diol can be prepared in high yield and selectivity by catalytic hydrogenation of 2-butyne-1,4-diol over a structured catalyst in the absence of a solvent. Since hydrogen is sparingly soluble in solvents, e.g. water, the absence of such solvents increases the economy of the hydrogenation process in that it results in higher turnover per time unit. The process avoids separation and recycling of a solvent for environmental protection.