A synthetic method steps of 2,2'-dihydroxy-4,4'-dimethoxybenzophenone are:
1) In the presence of a catalyst, m-xylylene dimethyl ether and oxalyl chloride were reacted at 70-80°C for 1.5 hours to obtain the intermediate product 2,2' 4,4'-tetramethoxybenzophenone, said The ratio of the amount of m-phthalyl ether to the amount of oxalyl chloride is 1:1-20, the catalyst used is azoisobutyronitrile or benzoyl peroxide, and the amount of the catalyst is the mass of m-xylylene 0.5%-2%;
2) React the intermediate product obtained in step 1) with the Lewis acid under the condition of an organic solvent as a solvent, the reaction temperature is 50°C, and the time is 2-3 hours. After stopping the reaction, add water for hydrolysis, liquid separation, rotary evaporation, and recrystallization. That is, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone is obtained;
The Lewis acid is one of AlCl3 , ZnCl2 , BF3 and polyphosphoric acid; the organic reagent is one of dichloroethane, toluene, xylene, nitrobenzene and chlorobenzene; The reactions in the steps 1) and 2) are carried out under the protection of inert gas.
