Method for preparing m-dichlorobenzene through catalysis of nano ZSM-5 molecular sieve and isomerization of p-dichlorobenzene

A technology of ZSM-5 and p-dichlorobenzene, which is applied in the field of preparing m-dichlorobenzene, can solve the problems of a large amount of acidic wastewater, the inability to regenerate the catalyst, and the inability to realize the continuous production process, so as to reduce production costs and achieve large-scale Industrial production, easy separation effect

Active Publication Date: 2014-04-09
HEILONGJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem of using anhydrous aluminum trichloride as a homogeneous catalyst in the process of producing m-dichlorobenzene by the isomerization reaction of p-dichlorobenzene. The technical problem of the continuous production process provides a method for the preparation of m-dichlorobenzene by catalyzing the isomerization of p-dichlorobenzene with nano-ZSM-5 molecular sieve

Method used

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  • Method for preparing m-dichlorobenzene through catalysis of nano ZSM-5 molecular sieve and isomerization of p-dichlorobenzene
  • Method for preparing m-dichlorobenzene through catalysis of nano ZSM-5 molecular sieve and isomerization of p-dichlorobenzene
  • Method for preparing m-dichlorobenzene through catalysis of nano ZSM-5 molecular sieve and isomerization of p-dichlorobenzene

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specific Embodiment approach 1

[0021] Specific embodiment one: The method for preparing m-dichlorobenzene by catalyzing the isomerization of p-dichlorobenzene with nano ZSM-5 molecular sieve in this embodiment is as follows:

[0022] 1. Prepare raw material liquid: mix p-dichlorobenzene and chlorobenzene evenly according to the mass ratio of 1: (1-5), and obtain the raw material liquid;

[0023] 2. Isomerization reaction: SiO 2 with Al 2 o 3 The molar ratio is (20-80):1, and the particle size is 20-40 mesh nano ZSM-5 molecular sieve, nano ZSM-5 molecular sieve modified by acid dealumination or nano ZSM-5 molecular sieve modified by alkali desiliconization. In the constant temperature zone of the bed reactor, activate for 40 to 120 minutes at a temperature of 400 to 550 ° C and a nitrogen flow rate of 50 to 100 ml / min, and then inject the raw material solution prepared in step 1 into the fixed bed reactor by continuous injection inside, and then at a temperature of 300-500°C, a pressure of 1-5MPa, and a m...

specific Embodiment approach 2

[0024] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the preparation method of the acid dealuminated nano ZSM-5 molecular sieve described in step two is as follows:

[0025] Mix the nano ZSM-5 molecular sieve with the hydrochloric acid solution with a concentration of 1~5mol / L according to the solid-liquid mass ratio of 1:(10~50), stir at 40~90°C for 4~10h, filter, and use deionized water After washing and drying, the nano ZSM-5 molecular sieve modified by acid dealumination is obtained. Others are the same as in the first embodiment.

[0026] The beneficial effect of this embodiment is: the acid dealumination modified nano ZSM-5 molecular sieve is used as the catalyst, although the acid content of the catalyst is lower than that before modification, but the acid dealumination modification removes part of the strong acid sites of the molecular sieve , resulting in secondary mesopores, effectively improving the diffusion pe...

specific Embodiment approach 3

[0027] Specific embodiment three: the difference between this embodiment and specific embodiment two is that the nano ZSM-5 molecular sieve and hydrochloric acid solution are mixed according to the solid-to-liquid mass ratio of 1: (20~30), and stirred at 50~80°C for 6~ 8h. Others are the same as in the second embodiment.

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Abstract

The invention discloses a method for preparing m-dichlorobenzene through catalysis of a nano ZSM-5 molecular sieve and isomerization of p-dichlorobenzene, and aims at solving the technical problems that the homogeneous catalyst, namely aluminium trichloride, cannot be reproduced, generates a lot of acid wastewater in the production process, and cannot achieve continuous production process in the process of preparing the m-dichlorobenzene by isomerization reaction of p-dichlorobenzene. The method comprises the following steps: 1. preparing a raw material solution, and 2. carrying out isomerization reaction. By adopting the method provided by the invention, the environment-friendly nano ZSM-5 molecular sieve solid acid catalyst is high in reaction activity and high in selectivity on a target product m-dichlorobenzene. The reaction process of the method is multi-phase continuous reaction, the reaction product can be easily separated from the catalyst, the operation is simple, and the catalyst can be continuously used, and is free of wastewater and exhaust emission. Therefore, not only is the production cost reduced, but also large-scale industrial production can be achieved. The method disclosed by the invention belongs to the field of preparation of m-dichlorobenzene.

Description

technical field [0001] The invention relates to a method for preparing m-dichlorobenzene. Background technique [0002] m-dichlorobenzene (m-DCB) is an important intermediate in the production process of fine chemicals, mainly used in the synthesis of pesticides, pharmaceuticals, dyes and pigments. With the wide application in pesticide synthesis and other fields, the demand for m-dichlorobenzene is increasing day by day. In terms of pesticides, m-dichlorobenzene is mainly used for the synthesis of fungicides (such as propiconazole, difenoconazole, imazalil, hexaconazole, furimazole, penconazole and amide azoles, etc.) and herbicides (such as New herbicides such as oxaconazole, diflufenican, oxazolin, thiazolimines, triazolinones, etc.). In medicine, m-dichlorobenzene is used to synthesize highly efficient, safe and broad-spectrum imidazole antifungal drugs (such as econazole, meconazole and ketoconazole), anti-inflammatory and analgesic diclofenac sodium (trade name Volta...

Claims

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Application Information

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IPC IPC(8): C07C25/08C07C17/358B01J29/40
Inventor 吴伟王功御白雪峰肖林飞
Owner HEILONGJIANG UNIV
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