Synthesis Research Of 2-methyl-1,3-benzenediol

2-Alkyl-1,3-benzenediol derivatives are important intermediates in organic synthesis,which are widely used in dyes,pharmaceuticals,pesticides,cosmetics and other fine chemical industries.Therefore,in this paper,the synthesis of 2-methyl-1,3-benzenediol is systematically studied,and the synthetic method of 2-methyl-1,3-benzenediol is successfully established using 1,3-cyclohexanedione as raw material,through Mannich reaction,catalytic hydrogenation and catalytic dehydrogenation three steps.The main contents are as follows:(1)The synthesis of 2-(N,N-dimethyl amino)methyl-1,3-Cyclohexanedione: With methanol as solvent,1,3-Cyclohexanedione,formaldehyde and dimethylamine as raw material,the parameters,including reactant molar ratio,reaction temperature,reaction time,additives in the Mannich reaction etc were studied.Finally,2-(N,Ntwo dimethylamino)methyl-1,3-cyclohexanedione was obtained in 98% yield.(2)The synthesis of 2-methyl-1,3-Cyclohexanedione: With Pd/C as a catalyst,the hydrogenation of 2-(N,N-dimethyl amino)methyl-1,3-Cyclohexanedione was studied,the parameters,including catalyst dosage,reaction temperature,medium pH value and hydrogen pressure were optimized.Thus 2-methyl-1,3-Cyclohexanedione was eventually obtained in 87% overall yield.(3)The synthesis of 2-methyl-1,3-benzenediol: The dehydrogenation of 2-methyl-1,3-Cyclohexanedione was synergistically catalyzed with Pd/C and sodium hydroxide under argon atmosphere.The effects of solvent and pH value of medium to the above reaction were studied.Thus,under the optimized reaction conditions,2-methyl-1,3-benzenediol was obtained in 80% overall yield by the recovering and recycling of 2-methyl-1,3-Cyclohexanedione.