Abstract: The present invention relates to a microwave chemical reaction apparatus characterized by comprising a means for heating a reaction liquid, which is capable of irradiating microwaves while controlling the output power according to the temperature of the reaction liquid, together with a means for forcibly cooling the reaction liquid from the outside, and being capable of precisely controlling the reaction temperature. The microwave chemical reaction apparatus can control the reaction temperature precisely, for example, within ±1° C. of a predetermined temperature, and can be applied to fine chemical reactions. Further, since reactions proceed rapidly in such an apparatus, mass production can be achieved by a relatively small-sized reaction apparatus.

Abstract: The present invention is characterized by subjecting 4,4?-diallyloxydiphenyl sulfone to a rearrangement reaction under microwave irradiation, preferably in molten state, to produce objective 3,3?-diallyl-4,4?-dihydroxydiphenyl sulfone efficiently in a short time, in high yield and in high purity. Further preferably, by carrying out said reaction in substantially oxygen-free atmosphere in the presence of at least one compound selected from a group consisting of an antioxidant, an organic basic compound and a chelate compound, the above-described object can be attained in more preferable manner.