Desulphurization Of α-Methylnaphthalene

α-methylnaphthalene is an important chemical raw material and medicine intermediate for synthesis of 1,4-naphthalene dicarboxylic acid, fluorescence whiting agent dyestuff, auximones etc. The industryα-methylnaphthalene fraction from coal tar contains 94-97%α-methylnaphthalene and 2-3% impurity methyl-benzothiophene in it. Now there is an urgent market demand to up 98%α-methylnaphthalene. If the methyl-benzothiophene is removed off, theα-methylnaphthalene's purity can reach over 98%. Thus thers is a considerable profit.The organic acid/hydrogen peroxide oxidative system can remove methy-benzothiophene off fromα-methylnaphthalene effectively. Two oxidative systems including acetic anhydride/hydrogen peroxide and formic acid/hydrogen peroxide has been investigated in the experiment. Oxidative desulphurization with 30% aqueous solution of hydrogen peroxide in the presence of the organic acid was studied, and the effects of organic acid, peroxide of hydrogen, temperature, reaction time , concentrated sulfuric acid, ultrasonic and nitrides on desulphurization ratio were investigated experimentally.The result indicates that: (1) For the formic acid/hydrogen peroxide, the sulphur removal rate can reach 100%; But for the acetic anhydride/ hydrogen peroxide, the sulphur removal rate can only reach 95%. So t-he formic acid/hydrogen peroxide is more effective than the acetic anhydride/hydrogen peroxide. (2) If adding concentrated sulfuric acid which acts as catalysis and enhanced acidity, the sulphur removal rate is increased. (3) For ultrasonic producing cavity effect and ehance the contact of two immiscible phases, the sulphur removal can be increased. (4) N-itride in feed can react with formic acid, so the sulphur removal rate is decreased. (5) The formic acid/hydrogen peroxide is more effective and more economical than the acetic anhydride/hydrogen peroxide.