P-Methoxybenzoic Acid CAS 100-09-4

The commercial manufacturing technique of p-methoxybenzoic acid is to utilize dimethyl sulfate to methylate p-hydroxybenzoic acid under alkaline conditions. Since p-hydroxybenzoic acid has a carboxyl group, more methylation is taken in. Alkali requires to be acidified with acid after the reaction, and p-hydroxybenzoic acid is also much more costly, therefore increasing the price. Meng Xiangjun, Zhang Baofa, and Ge Xin once reported using p-cresol as basic material to prepare p-methoxybenzoic acid through methylation and oxygen oxidation. Nonetheless, dimethyl sulfate is also made use of throughout methylation in this procedure, which additionally takes in a great deal of alkali and needs two steps to finish; in the process of oxygen oxidation, steel salts such as CoBr2 and MnBr2 likewise need to be made use of as drivers. While triggering heavy metal air pollution, it additionally boosts the expense of the procedure.

CN103848736A gives a synthesis approach of p-methoxybenzoic acid, which is identified in that it includes the complying with actions:
a. Add (4-methoxybenzyl) trimethylsilane right into the activator, include anhydrous solvent, and afterwards include the catalyst;

b. Connect the oxygen-filled bladder to the quartz activator and remove the air in the system so that the reaction continues under the oxidation of pure oxygen; or link the round condenser tube to the quartz reactor to permit the reaction to continue under the oxidation of air conduct;

c. Area the connected reactor under the irradiation of a xenon light (300W) to react; after the reaction item is identified by TLC and high performance fluid chromatography (4-methoxybenzyl)trimethylsilane to have entirely responded, vacuum rotating evaporation, Column chromatography separation and purification.