Study On The Catalysts Of The Phenol Hydroxylation With Hydrogen Peroxide And Discussion Of Technical Process

Benzenediol(catechol,hydroquinone)is a very important fine chemical product. Hydroquinone,which mainly used in sensitive material, latex, dye and medicine, can be produced to the developer of film,the thermal polymerization inhabitor ofsensitive resin,antioxidant,the intermediate of manufacturing anthraquinone,azo and other dyes. Catechol is mainly used for the intermediate of pesticides and dyes, also can be used the important intermediate of composed spicery and medicine. In addition, catechol is the main raw material of hair dye, latex hardener, plating bath additive and so on.There are several methods for synthesizing benzenediol, and they are,o-chloro -phenol hydrolyzed,anilin oxidation,diisopropylbenzene oxidation and the hydroxyl -lation of phenol and hydrogen peroxide and so on. Thereinto, the hydroxylation of phenol and hydrogen peroxide is the most significant method, and others will be washed out.The hydroxylation of phenol and hydrogen peroxide can be divided into several methods in according to different catalysts, which include four methods succeedding in industrialization: Rhone-Poulenc, Brichima, Enichem and Ube industries. Enichem which use the catalysts of improving gmolecular sieve and metal oxide and heteropoly compounds will be most popular method.Nine catalysts including Fe2O3,CoO,Gr2O3,PbO,SnOx,ZnO,SnO2,La2O3,MnO2 which are loaded onγ-Al2O3 are used in this paper, then the better be choosed to complex, producing double-component, tri-component and tetra-compenent catalysts to contrast effect, then the best catalyst will be chosed to catalyse the hydroxylation of phenol and hydrogen peroxide and reduce the industrialization cost. The percent conversion of phenol is 35%, and the of benzenediol is 99%, the ratio of hydroquinone to catechol is 0.78.In order to increase the ratio of hydroquinone to catechol, a new heteropoly compound (NH4)15[La(PMo9V2O39)2]·5H2O was synthesized to be used for the hydroxylation of phenol with hydrogen peroxide.The solvent is methanol, and the pH is 5, and the temperature is 70℃, and the ratio of phenol to hydrogen peroxide is 0.4, and the weight ratio of the catalyst to phenol is 0.1.Then, a perfect effect was reached Because of the phenol percent conversion 40 % and the benzenediol yield 39%.A discussion about reaction and reprocessing technology was refered in the paper.