Catalyst and preparation method for benzene hydroxylation to phenol

Abstract

The invention relates to a catalyst for preparing phenol by hydroxylation of benzene and a preparation method thereof. The component expression of the catalyst provided by the invention is Cs2.5(MIMPS)nH1.5-nPMo11VO40, wherein MIMPS indicates [N-(3-sulfonic)propyl-imidazolium] and n equals to 0.5-1.5. The preparation method provided by the invention comprises the following steps of: (1) preparingpure vanadium substituted heteropolymolybdates; (2) mixing the pure vanadium substituted heteropolymolybdates obtained from the step (1) with deionized water, adding dropwisely an inorganic cesium salt solution into the above solution with stirring, followed by a reaction, removing water from a suspending liquid obtained after the reaction so as to obtain a solid, drying to obtain a heteropolyacid inorganic cesium salt; (3) mixing the heteropolyacid inorganic cesium salt obtained from the step (2) with deionized water, adding dropwisely an MIMPS aqueous solution with stirring, followed by a reaction, removing the solvent from a suspending liquid obtained after the reaction so as to obtain a solid, and drying to obtain the catalyst for preparing phenol by hydroxylation of benzene. By the adoption of the catalyst provided by the invention, the yield of phenol can be obviously raised; in addition, the catalyst is easy to recover and convenient to repeatedly use.

Description

technical field [0001] The invention relates to an organic-inorganic double-modified heteropolyacid catalyst and a preparation method, in particular to a catalyst and a preparation method for the hydroxylation of benzene to phenol. Background technique [0002] Phenol is an important organic chemical raw material, widely used in petrochemical, agricultural and plastic industries, and the world demand is increasing year by year. At present, the industrial production method of phenol is mainly the cumene method. This method adopts the alkylation of benzene to obtain cumene, the oxidation of cumene to obtain cumene peroxide, and the decomposition of cumene peroxide to produce phenol. The disadvantages of this process are large energy consumption, low phenol yield, the presence of an explosive intermediate product-cumene peroxide, the consumption of national strategic resource propylene, and the production of by-product acetone in an equimolar amount to phenol and acetone The d...

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Problems solved by technology

The most obvious disadvantage of using pure heteropolyacids as homogeneous catalysts to catalyze benzene liquid-phase synthesis of phenol is the difficulty in catalyst recovery. In view of this, Chinese patent CN1788843 uses a sol-gel method to immobilize molybdenum vanadium phosphopolyacids, and finds that in benzene The catalyst prepared in the hydrogen peroxide hydroxylation reaction can be reused many times, but the catalyst preparation process is relatively complicated

[0008] So far, on the publicly reported catalysts, the conversion rate of benzene and the yield of phenol during the hydroxylation of benzene and hydrogen peroxide to phenol are relatively low, and molybdenum vanadium phosphopolyacids are used to modify molybdenum vanadium phosphopolyacids simultaneously with organic and inorganic groups. The hydroxylation process of benzene and hydrogen peroxide has not been reported yet

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