Electrocatalytic Activity And Application Of Nanocrystalline TiO₂ Film Modified Ti Electrode In The Electrosynthesis Process Of P-Aminophenol

Recently, p-Aminophenol(PAP) is an important medicine, rubber and dye intermediate with wide uses and optimum application prospects. With the development of medicine, rubber and dye industry, the need for p-aminophenol was yearly increased both in China and abroad, however the supply is insufficient. The technology of direct electrochemical synthesis of PAP is characterized by mild reaction conditions, high product purity and reduced waste, and is called as "Green Technology". As a research contents of the subjects which funded by Henan Key Research Projects (No. 03223023800) in 2003, the follow contents have been studied in this dissertation.In the electro-synthesis process of p-aminophenol, supporting electrolytes were sulfuric acid aqueous solution, and the reaction solution were the mixtures consisting of p-aminophenol, water, H₂SO₄, aniline and un-reacted NB. The analysis method that can simultaneously and rapidly analyzes the contents of p-aminophenol and aniline in reaction mixture liquid was not found in literature. In this paper, a new analysis method that can simultaneously analyzes the contents of p-aminophenol and aniline in reaction mixture liquid was proposed by combining gas phase chromatography method with equivalence absorbency double-wavelength UV spectrophotometry method.The methods of sacrificial anode and directly hydrolyzing have been used to prepare Ti/nano- TiO₂ film electrode. The precursor gels and product were characterized with DSC-TG XRD, SEM, were used to characterize the structure of nanocrystalline of TiO₂ . Results showed TiO₂ is of anatase structure and with size distribution ranged in 10nm to 30nm by Scherrer formula. Nanocrystalline TiO₂ films were selected at T=450℃ for 40 min . It is can be seen that the grain distributing uniformly and the component keeping stably, and the grain's diameter is accordant to the result of Scherrer formula in the nanocrystalline film. Finally, it is found that the sacrificial anode method has more economic and prosperous future when this two methods were compared.