PURPOSE: To obtain an unsaturated carboxylic acid in high yield and in high selectivity by subjecting a saturated monocarboxylic acid and formaldehyde or a formaldehyde derivative to contact reaction in the presence of a specific catalyst in a gas phase.
CONSTITUTION: A saturated monocarboxylic acid is reacted with formaldehyde or a formaldehyde derivative in the presence of a catalyst shown by the formula CraSbbXcOd (X is Cu, Bi, Zr, Mo, W, V, etc.; a-d are atomic ratio of each element, when a=1, b is 0.01-10, c is 0-10 and d is number of oxygen atoms required for satisfying valence of each component) at 200-500°C to give the aimed substance. The reaction can be stably maintained for a long period by adding 0.1-10vol.% molecular oxygen to a raw material gas. The molar ratio of the saturated monocarboxylic acid and formaldehyde is 1:10-10:1.
KINOSHITA YUTAKA
KITA TERUO
