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Method for preparing 2,6-dimethylnaphthalene from isoprene and methyl p-benzoquinone

A technology of isoprene and dimethylnaphthalene, which is applied in the field of preparing 2,6-dimethylnaphthalene, can solve the problems of complex raw material components of coal tar, low content of target products, harsh reaction system, etc., and achieve product yield High efficiency, short reaction route and mild reaction conditions

Active Publication Date: 2020-06-02
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The typical production method of dimethyl naphthalene is direct extraction from coal tar, but the raw material components of coal tar are complex, the separation steps are cumbersome, and the content of the target product is less
In addition, there are toluoylation method and o-xylene alkylation method to synthesize dimethyl naphthalene, but there are problems with harsh reaction systems, and most of toluene and o-xylene are catalyzed from naphtha. Reorganized to obtain

Method used

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  • Method for preparing 2,6-dimethylnaphthalene from isoprene and methyl p-benzoquinone
  • Method for preparing 2,6-dimethylnaphthalene from isoprene and methyl p-benzoquinone
  • Method for preparing 2,6-dimethylnaphthalene from isoprene and methyl p-benzoquinone

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Embodiment 1

[0029] [C 4 mim]Zn 2 Cl 5 The preparation adopts the following method, respectively 1.72g ionic liquid [C 4 mim]Cl (10mmol) and 2.72g (20mmol)) of zinc chloride were added to a round-bottomed flask, stirred at 150°C for 2 hours, and cooled to room temperature after the reaction to obtain the final zinc-containing ionic liquid [C 4 mim]Zn 2 Cl 5 catalyst.

[0030] Other Lewis acid catalysts can directly use commercial catalysts.

Embodiment 2

[0032] Add a certain amount of isoprene, methyl-p-benzoquinone and Lewis acid catalyst into the hydrothermal reaction kettle, and react at different temperatures. After a certain period of time, take a sample and add about 1mL tetrahydrofuran to dilute, mix well, and centrifuge to separate the product. Qualitative analysis by GC-MS, quantitative analysis by GC external standard method. The reaction results are shown in Table 1.

[0033] Table 1. The reaction results of isoprene and methyl-p-benzoquinone under common heating conditions

[0034]

[0035]

[0036] The above results show that in the temperature range of 20°C-80°C, the ratio of isoprene / methyl-p-benzoquinone / catalyst is between 10-100, and the reaction is 20-90 hours, and dimethylhexahydronaphthalene di Ketone, the yield is between 60%-95%, it is better to use [C 4 mim]Zn 2 Cl 5 React at room temperature for 20-30 hours or heat to 40-50°C for 60-90 hours.

Embodiment 3

[0038]Add a certain amount of isoprene, methyl-p-benzoquinone and Lewis catalyst into the reaction tube, and react under microwave conditions of different powers. After a certain period of time, take a sample and add about 1ml tetrahydrofuran to dilute, mix well, and centrifuge to separate the product. Qualitative analysis by GC-MS, quantitative analysis by GC external standard method. The reaction results are shown in Table 2.

[0039] Table 2. Reaction results of isoprene and methyl-p-benzoquinone under microwave heating conditions

[0040]

[0041]

[0042] The above results show that between 200W-1000W of microwave power and 10-80 minutes of reaction, dimethyl hexahydronaphthalenedione can be obtained, and the yield is still between 60%-97%, preferably at 600-800W for 40 minutes. -60 hours.

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Abstract

The invention relates to a method for preparing 2,6-dimethylnaphthalene from isoprene and methyl p-benzoquinone. The process comprises two steps: 1, carrying out a Diels-Alder reaction on isoprene andmethyl p-benzoquinone under the action of a Lewis acid catalyst or pure thermal synthesis at 20-80 DEG C to generate a dimethyl hexahydronaphthalene dione intermediate product; and 2, carrying out dehydrogenation and deoxidation under the action of a Cu-based catalyst to generate 2,6-dimethylnaphthalene, wherein the synthesis of the intermediate product can be realized by taking isoprene and methyl p-benzoquinone from biomass resources as raw materials through common heating or microwave heating in a tank reactor, dehydrogenation and deoxidation reactions can be carried out in a fixed bed reactor, and the reaction intermediate is directly injected into a reaction tube or passes through a catalyst bed layer under purging of carrier gas to obtain 2,6-dimethylnaphthalene. The process is simple in reaction procedure and high in target product selectivity, and a new route for preparing dimethylnaphthalene from biomass resources is provided.

Description

technical field [0001] The invention relates to a method for preparing 2,6-dimethylnaphthalene from isoprene and methyl-p-benzoquinone. Specifically, from isoprene and methyl-p-benzoquinone, under appropriate conditions, Diels-Alder reaction occurs under the action of Lewis acid catalyst or thermal synthesis and dehydrogenation and deoxygenation occur under the action of Cu-based catalyst. Reaction, the method for preparing 2,6-dimethylnaphthalene. The isoprene and methyl-p-benzoquinone of the present invention can be obtained from petroleum resources, and can also be obtained from biomass conversion, so the raw materials have the characteristics of regeneration. In addition, this route obtains naphthyl aromatic compounds through a two-step reaction. The reaction route is short, the operation is convenient, and the product yield is high. It provides a new method for directly preparing disubstituted naphthyl aromatic chemicals from biomass platform compounds. Background tech...

Claims

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Application Information

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IPC IPC(8): C07C1/207C07C15/24
CPCC07C1/2076C07C45/69C07C2523/72C07C2602/28C07C15/24C07C49/637
Inventor 李昌志孟庆伟肖钰雪王爱琴张涛
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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