ZnO/SBA-15 composite nano-catalyst, preparation method and application thereof

Abstract

The invention relates to a nano composite catalyst ZnO / SBA-15, which has the mass percentage of compositions as follows: ZnO ranges from 5 to 15 percent; SBA-15 ranges from 85 to 95 percent. SBA-15 ethanol-water suspension is mixed from an ethanol aqueous solution and SBA-15; the SBA-15 ethanol-water suspension, being stirred at the temperature ranging from 60 DEG C to 120 DEG C, is added with the zinc salt-absolute ethanol solution with a concentration of 0.001 to 0.20 mol / L and equivoluminal ethanol solution organic amines with a concentration of 0.01to 1.6 mol / L; then the mixed solution is aged for 1 to 5 hour(s), and then is let stand and filtrated; the sediments are washed by deionized water to be neutral; and the ZnO / SBA-15 catalyst is made by drying and roasting the sediments. The nano composite catalyst has the advantages of simple process, homogeneous distribution of particles, good dispersion, high conversion rate of aromatic isocyanate, good selectivity, etc.

Description

technical field [0001] The invention belongs to a ZnO / SBA-15 composite nano-catalyst and its preparation method and application, in particular to a catalyst for directly synthesizing nano-ZnO on the surface of molecular sieve SBA-15 and its preparation method and aromatic carbamate decomposition to produce aromatic Applications in isocyanate reactions. Background technique [0002] Nano-ZnO has excellent optical, electrical, chemical and biological properties and is widely used in chemical, electronic, biopharmaceutical and coatings, sensors, dielectric materials, inks, chemical fibers, rubber and other production and research fields. In the chemical industry, ZnO is widely used as a catalyst and desulfurizer, and the high surface activity of nano-ZnO can improve the selectivity and catalytic efficiency of the catalyst. In recent years, nano-ZnO particles have become a research hotspot. The main methods for preparing ZnO nanostructures include carbothermal reduction, vapor ...

AI Technical Summary

Problems solved by technology

In the process of preparing aromatic isocyanate by the decomposition of aromatic amino acid ester, Sydor (U.S.Pat.3,734,941) proposes that 2,4-toluene-ethyl carbamate is decomposed in the presence of ferric chloride, and the shortcoming of this reaction is that the yield is low , the formation of a large number of polymerization by-products, the catalyst is easy to decompose, and the reaction equipment is corroded

Alper etc. (U.S.Pat.5,457,229) propose to add halogenated catechol borane to receive the alcohol that generates, improve the yield of diphenylmethane diisocyanate, the shortcoming of this technique is that reaction needs to consume a large amount of tertiary amines (generate quaternary ammonium salt ), which increases the cost, which is not conducive to industrial production, and at the same time, corrosive hydrochloric acid will be generated

Sundermann et al. (U.S.Pat.4,388,246) use diphenyl ether as a solvent and phthaloyl chloride as an auxiliary agent to decompose aromatic carbamate, and the selectivity of isocyanate can reach 98.9%. The shortcoming of this method is that the reaction time is long , the residual chlorine in the product affects the quality of isocyanate