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Method for preparing m-dichlorobenzene by catalyzing isomerization of p-dichlorobenzene by using nano ZSM-12 molecular sieve

A ZSM-12, p-dichlorobenzene technology, applied in molecular sieve catalysts, chemical instruments and methods, preparation of halogenated hydrocarbons, etc., can solve the problem of inability to achieve continuous production process, carbon deposition inactivation m-dichlorobenzene selectivity, A large number of acidic wastewater and other problems, to achieve the effect of large-scale industrial production, strong anti-deactivation ability of carbon deposition, and lower production costs

Inactive Publication Date: 2015-05-13
HEILONGJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the use of anhydrous aluminum trichloride homogeneous catalyst in the process of preparing m-dichlorobenzene by the isomerization reaction of p-dichlorobenzene cannot be regenerated, a large amount of acidic waste water is produced in the production process, and the production process cannot be realized. Continuous technical problems, and the use of ZSM-5 molecular sieve due to its small pore size leads to the problem of carbon deposition deactivation and low selectivity of m-dichlorobenzene, and a nano ZSM-12 molecular sieve is provided to catalyze the dichlorobenzene A new method for the preparation of m-dichlorobenzene by isomerization of chlorobenzene

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  • Method for preparing m-dichlorobenzene by catalyzing isomerization of p-dichlorobenzene by using nano ZSM-12 molecular sieve
  • Method for preparing m-dichlorobenzene by catalyzing isomerization of p-dichlorobenzene by using nano ZSM-12 molecular sieve
  • Method for preparing m-dichlorobenzene by catalyzing isomerization of p-dichlorobenzene by using nano ZSM-12 molecular sieve

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specific Embodiment approach 1

[0015] Specific embodiment one: The method for preparing m-dichlorobenzene by catalyzing the isomerization of p-dichlorobenzene with nano ZSM-12 molecular sieve in this embodiment is as follows:

[0016] 1. Preparation of raw material liquid: mix p-dichlorobenzene and chlorobenzene evenly according to the mass ratio of 1: (3-8), to obtain the raw material liquid;

[0017] 2. Isomerization reaction: SiO with a molar ratio of (60-200): 1 2 with Al 2 o 3 , Nano ZSM-12 molecular sieves or ZSM-12 molecular sieves modified by alkali desiliconization are loaded into the constant temperature zone of the fixed bed reactor, and activated at a temperature of 500-550°C and a nitrogen flow rate of 20-80ml / min for 1~ 2h, inject the raw material solution prepared in step 1 into the fixed-bed reactor by continuous injection, and then inject it at a temperature of 400-550°C, a pressure of 0.5-5MPa, and a mass space velocity of 0.5-4.0h -1 1. Reaction under the condition that the flow rate o...

specific Embodiment approach 2

[0019] Embodiment 2: This embodiment differs from Embodiment 1 in that step 1 mixes p-dichlorobenzene and chlorobenzene uniformly at a mass ratio of 1:5. Other steps and parameters are the same as those in Embodiment 1.

specific Embodiment approach 3

[0020] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that the preparation method of the ZSM-12 molecular sieve modified by alkali desilication described in step 2 is as follows:

[0021] Mix nano ZSM-12 molecular sieves with NaOH solution with a concentration of 0.1-1.0 mol / L, and stir at 25°C-80°C for 1-10 hours, wash the collected solid phase with deionized water, dry it with 0.5mol / L L NH 4 NO 3 The aqueous solution is ion-exchanged, filtered, washed with deionized water, dried, and finally calcined to obtain the nanometer ZSM-12 molecular sieve modified by alkali desiliconization. Other steps and parameters are the same as those in Embodiment 1 or Embodiment 2.

[0022] In this embodiment, the nanometer ZSM-12 molecular sieve catalyst is modified by alkali treatment. The alkali treatment causes local defects and secondary mesopores in the molecular sieve lattice, which increases the mesopore volume and outer surfa...

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Abstract

The invention discloses a method for preparing m-dichlorobenzene by catalyzing isomerization of p-dichlorobenzene by using a nano ZSM-12 molecular sieve and belongs to the field of production of fine chemicals to solve the technical problems that an anhydrous aluminum chloride homogeneous catalyst which is used in preparation of m-dichlorobenzene by virtue of isomerization of p-dichlorobenzene cannot be regenerated for use and generates a lot of acidic wastewater, and the problem of relatively low selectivity of m-dichlorobenzene prepared by adopting a ZSM-5 molecular sieve. The method for preparing m-dichlorobenzene comprises the following steps: 1, preparing a raw material solution; and 2, filling SiO2, Al2O3 and the nano ZSM-12 molecular sieve into a constant-temperature zone of a fixed bed reactor, activating, and injecting the raw material solution by adopting a continuous injecting manner to perform catalytic reaction. According to the method disclosed by the invention, an environment-friendly nano ZSM-12 molecular sieve solid acid catalyst is used, so that a continuous heterogeneous catalysis reaction process can be realized, the selectivity to the target product namely m-dichlorobenzene is high, the reaction product can be easily separated from the catalyst, and large-scale industrial production can be realized.

Description

technical field [0001] The invention belongs to the field of fine chemical production, and in particular 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 intermediates for pesticides, medicines, dyes and pigments. With the wide application of m-dichlorobenzene in pesticide synthesis and other fields, its demand 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 ket...

Claims

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Application Information

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IPC IPC(8): C07C17/358C07C25/08B01J29/70
Inventor 吴伟靳佳乐白雪峰肖林飞王功御戚鑫
Owner HEILONGJIANG UNIV
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