PROCESS FOR PRODUCING (METH)ACRYLIC ACID OR (METH)ACROLEIN

摘要

A process for producing (meth)acrolein or (meth)acrylic acid, comprising carrying out vapor-phase catalytic oxidation reaction of propylene, propane, isobutylene or (meth)acrolein with the use of molecular oxygen or gas containing molecular oxygen in the presence of a composite oxide catalyst by means of a multitubular reactor having multiple reaction tubes loaded with the catalyst, so that (meth)acrolein or (meth)acrylic acid can be obtained with high yield stably for a prolonged period of time without local (unevenly distributed) extreme lowering of catalytic activity. There is provided a process wherein at an initial stage of operation the difference between the temperature of heat medium and the peak temperature of catalyst is set for 20 to 80°C and wherein during the operation any change of peak temperature (T) of catalyst in the direction of tube axis is regulated so as to fall within a given range.