Catalytic synthesis method for preparing cresol by toluene one-step hydroxylation reaction

A synthesis method and hydroxylation technology, applied in chemical instruments and methods, preparation of organic compounds, catalysts for physical/chemical processes, etc. Difficulty and other problems, to achieve the effect of reducing preparation cost, mild reaction conditions, and improving catalytic activity and selectivity

Inactive Publication Date: 2010-07-28
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Usually, the titanium-silicon molecular sieve prepared by hydrothermal synthesis has good catalytic activity, but its particle size is small (0.1-5 μm), it is difficult to directly use it in liquid-phase catalytic reaction for recovery, and it cannot meet the requirements of industrial equipment for catalyst strength, life, and shape and other requirements

Method used

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  • Catalytic synthesis method for preparing cresol by toluene one-step hydroxylation reaction
  • Catalytic synthesis method for preparing cresol by toluene one-step hydroxylation reaction
  • Catalytic synthesis method for preparing cresol by toluene one-step hydroxylation reaction

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] The untreated diatomaceous earth was raised from room temperature to 1000°C at a rate of 250°C / h, and kept at this temperature for 12h. Mix 3.6g of MFI titanium silicate molecular sieve with 5.4g of diatomite calcined at high temperature, press into tablets, and crush to 20-40 mesh.

[0037] The one-step hydroxylation reaction of toluene is carried out in a fixed-bed glass reactor with an inner diameter of 15mm. The amount of catalyst used is 7g. 2 o 2 (30%) and the mixed solution of acetone is input reactor by metering pump by the bottom of reactor, wherein: toluene / acetone (mass ratio)=1 / 3, toluene / H 2 o 2 (molar ratio)=0.92 / 1, the reaction mass space velocity is 5.0h -1 Start timing from the outflow of the first drop of liquid, take a sample and analyze after the reaction is stable for 1h, and the reaction results are shown in Table 1.

Embodiment 2

[0039] The difference from Example 1 is the composition of the raw material mixture. In the present embodiment, toluene / acetone (mass ratio)=1 / 3.5, toluene / H 2 o 2 (Molar ratio) = 0.69 / 1. The reaction results are shown in Table 1.

Embodiment 3

[0041] The difference from Example 1 is the composition of the raw material mixture. In the present embodiment, toluene / acetone (mass ratio)=1 / 4, toluene / H 2 o 2 (Molar ratio) = 0.57 / 1. The reaction results are shown in Table 1.

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Abstract

The invention discloses a catalytic synthesis method for preparing cresol by toluene one-step hydroxylation reaction, which is characterized in that: composite catalyst consisting of titanium silicalites and kieselguhr is adopted, the hydrogen peroxide is used as oxidant and the acetone is used as solvent, a continuous fixed-bed catalytic reaction system is adopted, and the reaction is carried out in solid-liquid two phases. The titanium silicalite in the composite catalyst has a MFI structure, and the kieselguhr is subjected to modification by a specific chemical method; and meanwhile, rare-earth elements are used to carry out modification on the catalyst, so that the catalyst has higher catalytic performance for the cresol-prepared toluene one-step hydroxylation reaction. The reaction process has the characteristics of high selectivity of cresol product, high effective utilization ratio of hydrogen peroxide, molar ratio of o-cresol to p-cresol in the cresol products of 1.3 to 1.4, mild reaction condition, simple and safe technological process, environmental protection and the like; therefore, the invention provides an economic and ecological method for preparing cresol.

Description

technical field [0001] The invention relates to a catalytic synthesis method and process for preparing cresol by one-step hydroxylation reaction of toluene. In the catalytic synthesis method, a compound prepared from titanium silicon molecular sieve and diatomite is selected as a catalyst, hydrogen peroxide is used as an oxidant, and acetone is used as a solvent. , carried out in a fixed-bed reactor system, after the reaction, the catalyst can be regenerated and reused in situ without disassembly and separation, thus greatly reducing the production cost of cresol. technical background [0002] Cresol is an important class of fine chemical intermediates, including three isomers, namely o-cresol, m-cresol and p-cresol. Cresol is widely used in the fields of medicine, pesticides, spices, dyes, coatings, polymerization inhibitors, antioxidants, ultraviolet absorbers, rubber additives, fuel additives, feed additives and synthetic materials. [0003] The traditional preparation m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/07C07C37/60B01J29/89
Inventor 卢冠忠杨春燕郭杨龙郭耘张志刚王筠松王艳芹龚学庆詹望成刘晓晖
Owner EAST CHINA UNIV OF SCI & TECH
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