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Method for preparing 2,5-dimethyl phenol through direct catalytic hydroxylation of p-xylene

A technology of dimethyl phenol and catalyzed hydroxyl group, which is applied in the field of preparation of aromatic phenolic compounds, can solve the problems of pollution, many reaction steps, and low utilization rate of atoms, and achieve the effects of easy acquisition, few reaction steps, and recyclable solvents

Inactive Publication Date: 2011-09-28
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It overcomes the shortcomings of the traditional process, such as many reaction steps, serious pollution, and low utilization rate of atoms.

Method used

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  • Method for preparing 2,5-dimethyl phenol through direct catalytic hydroxylation of p-xylene
  • Method for preparing 2,5-dimethyl phenol through direct catalytic hydroxylation of p-xylene
  • Method for preparing 2,5-dimethyl phenol through direct catalytic hydroxylation of p-xylene

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Experimental program
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Effect test

Embodiment 1

[0017] Add 16.0g acetonitrile, 0.08g PG8, 0.8g p-xylene, 18.7g 30% H 2 o 2 , reacted at 60°C for 5 hours. Samples were taken for gas chromatographic analysis. The conversion of p-xylene was 55.9%, and the yield of 2,5-dimethylphenol was 10.1%.

Embodiment 2

[0019] Add 12.0g acetonitrile, 0.04g PG8, 0.8g p-xylene, 16.0g 30% H 2 o 2 , reacted at 40°C for 4 hours. Samples were taken for gas chromatographic analysis. The conversion of p-xylene was 47.8%, and the yield of 2,5-dimethylphenol was 8.6%.

Embodiment 3

[0021] Add 24.0g of acetonitrile, 0.16g of PG8, 0.8g of p-xylene, 24g of 30% H 2 o 2 , reacted at 70°C for 7 hours. Samples were taken for gas chromatographic analysis. The conversion of p-xylene was 67.4%, and the yield of 2,5-dimethylphenol was 9.3%.

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Abstract

The invention provides a method for preparing 2,5-dimethyl phenol through the direct catalytic hydroxylation of p-xylene. In the method, acetonitrile is taken as a solvent, H2O2 is taken as a hydroxylation reagent, C.I. pigment green 8 is taken as a catalyst, the p-xylene is subjected to one-step catalytic hydroxylation at the temperature of between 40 and 70 DEG C for 4 to 7 hours to form the 2,5-dimethyl phenol, and the mass ratio of reaction materials, namely the H2O2 to the acetonitrile to the C.I. pigment green 8 to the p-xylene is (6-9):(15-30):(0.05-0.2):1. The catalyst is readily available, a few reaction steps are performed, the H2O2 can be fully utilized, the solvent can be recycled, and a few three wastes (waste water, waste gas and waste residues) are generated; and the catalytic hydroxylation operation process is easy to implement.

Description

technical field [0001] The invention belongs to the preparation method of aromatic phenolic compounds, and particularly proposes a method for preparing 2,5-dimethylphenol by direct catalytic hydroxylation of p-xylene. Background technique [0002] 2,5-Dimethylphenol is an important intermediate in organic synthesis. Mainly used in the production of hypolipidemic drug gemfibrozil, rubber anti-aging agent, developer, and dye intermediates. There are some reports in the literature on the synthesis of 2,5-dimethylphenol from p-xylene. For example, Tang Weiping uses p-xylene as raw material to synthesize 2,5-dimethylphenol through sulfonation and alkali fusion (chemical reagents, 1999, 21 (6): 382); , 5-dimethylnitrobenzene, and then palladium carbon-ammonium formate catalyzed hydrogen transfer reduction reaction, diazotization, and hydrolysis to finally obtain 2,5-dimethylphenol (Fine Chemical Intermediates, 2005, 35 (1): 38-39). However, these methods have the problems of m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/07C07C37/60
Inventor 张天永王晓邱明艳李彬何萌
Owner TIANJIN UNIV
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