Synthesis
To the salt kettle add water 1800kg, sulfonesulfonyl chloride 700kg, sodium bicarbonate 450kg and sodium sulfite 330kg, salt reaction at atmospheric pressure, reaction temperature of 60 , holding time of 4 hours, carbon dioxide gas produced by the reaction and a small amount of water evacuation, to be the reaction is complete, while the heat is 40-50 filtration, the mother liquor is pumped by vacuum into the methylation kettle, the filtration residue is separate. The slag was treated separately. The mother liquor is further heated to 70 in the methylation kettle, and then 158kg of monochloromethane gas is passed under the pressure of 0.5kg/cm3, and the crystallization is cooled by heat preservation. When the crystallization mother liquor cooled to 40 , discharge filtration, filter cake and then centrifuge centrifugation, filtration mother liquor and centrifugation mother liquor centralized distillation, water vapor condensation through the condenser condensation set, resulting in a separate treatment of waste salt. After the wet product is dried by the drier, methylsulfonylbenzene is obtained. The content of methylsulfonylbenzene is above 99%, and the yield is about 70%. Methylsulfonylbenzene is brominated to obtain o-bromo methylsulfonylbenzene.
The reaction flask was charged with 0.05 mol (0.1eq) of o-bromomethylsulfonylbenzene, 0.55 mol (1.1eq) of magnesium flakes, a few particles of monomers of iodine, and 300 ml of THF, stirred, warmed up to reflux, and triggered by Gram's initiation, and the addition of m-bromotoluene, 0.45 mol (0.9eq) was continued dropwise in the refluxed state. Dropping finished reflux holding reaction, the reaction time to, lower the temperature to -60.0 , began to drop the addition of trimethyl borate 1.0mol (2.0eq), dropping finished, holding reaction until the raw material reaction is complete, raise the temperature, add water, drop hydrochloric acid hydrolysis, adjust the pH to 1-2, hold the reaction time to, reaction time to, rotary evaporation, pumping dry, pulping and purification, drying to obtain a white solid 2-methylsulfonylphenylboronic acid 0.44 mol, moisture 0.05%, purity 98.64%, yield 88.0%.
