Preparation Of Tetrasulfonated Metal Phthalocyanines/MCM-41 And Their Catalytic Performance In Phenol Hydroxylation

Metallophthalocyanines is a class of planar macrocyclic complex with highly conjugatedπelectron system, and its structure is similar to that of iron porphyrin, an active center of cytochrome P450 monooxygenase. Because of its bright color, high color strength, low production costs and excellent stability, metallophthalocyanines have been widely used as dyes and pigments. In recent years, a large number of structural modified phthalocyanines have been prepared, with excellent electrical, optical, magnetic and catalytic properties. They have many prospecting applications, such as chemistry sensors, solar energy cells, electrochromic substances, photodynamic therapy, laser recorder materials, liquid crystal display materials, nonlinear optical materials, catalytic fields and so on. However, due to the poor solubility in solvents of non-substituted metallophthalocyanine, and easy aggregation in homogeneous media of substituted metallophthalocyanine, their applications are limited to a large extent. Therefore, preparation of metallophthalocyanine/zeolite composite catalyst by encapsulation of soluble metallophthalocyanine in zeolite, is important both in theoretical research and practical application.In this paper, water-soluble tetrasulfonated metal phthalocyanines were prepared through the DBU method, and then the complexes were encapsulated into MCM-41 by means of hydrothermal-extraction method. The tetrasulfonated metal phthalocyanines/MCM-41 catalysts (Ex-MPcTs/MCM-41) were characterized and their catalytic performances were investigated. The main research results are as follows:(1) Tetrasulfonated iron (cobalt, copper) phthalocyanines were synthesized through DBU method using sodium 3,4-dicyanobenzenesulfonate as intermediate, and were characterized by FT-IR spectra, UV-Vis spectra, elemental analysis and 1H NMR.(2) Ex-MPcTs/MCM-41 catalysts were synthesized by two steps. The first step was hydrothermal process using MPcTs and cetyltrimethylamminimu bromide(CTMAB) as template, sodium metasilicate nonahydrate as silica source. Then CTMAB was removed by extraction with a solution of hydrochloric acid in ethanol. The amounts of MPcTs encapsulated inside the pore of MCM-41 were measured by inductively coupled plasma-atomic emission spectrometry(ICP). The properties of the catalysts were characterized by XRD, UV-Vis diffuse reflectance spectra, TGA, FT-IR spectra and N2 adsorption.(3) Established HPLC analysis method for the phenol hydroxylation reaction: chromatographic column C18, column temperature 25℃, detection wavelength 277 nm, flow rate 1.0 mL/min, injection volume 20μL, initial mobile phase ratio V(methanol):V(water)= 30:70, gradient elution, the methanol concentration reached 100%after 20 min.(4) The reaction of phenol hydroxylation was conducted using Ex-FePcTs/MCM-41 as catalyst,30 wt% H2O2 as oxidation. Under optimized reaction conditions, phenol conversion and diphenol selectivity reaches 26.88%and 63.59%respectively, and the turnover number of phenol almost the same after recycling three times.