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Method for alkyl transfer of beta-methylnaphthalene to prepare 2,6-dimethylnaphthalene

A technology of dimethylnaphthalene and methylnaphthalene, applied in chemical instruments and methods, organic chemistry, hydrocarbons, etc., can solve the problems of low selectivity, catalyst coke deposition, and high production costs

Inactive Publication Date: 2006-04-26
HEILONGJIANG UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problems that the existing method for preparing 2,6-dimethylnaphthalene has too long production process, high production cost, low selectivity of 2,6-dimethylnaphthalene, and serious carbon deposition on the catalyst, the invention provides a The method for preparing 2,6-dimethylnaphthalene by the transalkylation of β-methylnaphthalene with short production process and low cost, the molar ratio of β-methylnaphthalene, transalkylation agent and solvent is 1: 1~ 2: 0.5~8 composition mixture, at the reaction temperature of 350°C~550°C, under the supercritical reaction pressure of 3.1~12.0MPa, for 0.1~3h -1 The space velocity, through the catalyst bed, carry out the transfer alkylation reaction to synthesize 2,6-dimethylnaphthalene in one step

Method used

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specific Embodiment approach 1

[0006] Specific embodiment 1: In this embodiment, the molar ratio of β-methylnaphthalene, transalkylating agent and solvent is 1:1~2:0.5~8 to form a mixture, and the reaction temperature is 350°C~550°C , under the supercritical reaction pressure of 3.1~12.0MPa, take 0.1~3h -1 The space velocity is passed through the catalyst bed, and the transfer alkylation reaction is carried out to synthesize 2,6-dimethylnaphthalene in one step.

specific Embodiment approach 2

[0007] Specific embodiment two: the operation process of this embodiment is as follows: will use Mg 2+ The Hβ zeolite modified by BaO is partially exchanged and crushed into 20-40 mesh particles, weighed 0.5-1 g, and added to the constant temperature zone of the supercritical reactor. The space above and below the catalyst is made of 20-40 mesh quartz sand filling. The inner diameter of the supercritical reactor is 8 mm, the length is 400 mm, and a thermowell with a diameter of 3 mm is built in. Before the reaction, the catalyst should be activated at 520°C for 2 hours under a nitrogen atmosphere; then the temperature of the reactor was lowered to 435°C to start the reaction. Press 0.6h -1 (in terms of β-methylnaphthalene), the reaction solution (molar ratio is 1: 1.4: 4) injected by β-methylnaphthalene, mesitylene and mesitylene with a single plunger micro metering pump In the reactor, it is preheated through the quartz sand preheating section first, and then enters the ca...

specific Embodiment approach 3

[0008] Embodiment 3: The difference between this embodiment and Embodiment 2 is that the solvent is xylene or other trimethylbenzenes, both of which can achieve the same effect as described in Embodiment 2. The solvent of the present invention except described xylene or trimethylbenzene, as long as it can be miscible with β-methylnaphthalene and alkylating agent, and basically does not participate in the organic compound of reaction, so all should be included in the protection of the present invention. within range.

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Abstract

The present invention relates to preparation of 2, 6-dimethyl naphthalene, and is especially beta-methyl naphthalene transalkylating process of preparing 2, 6-dimethyl naphthalene. The beta-methyl naphthalene transalkylating process of preparing 2, 6-dimethyl naphthalene includes compounding mixture with beta-methyl naphthalene, transalkylating agent and solvent in the molar ratio of 1 to 1-2 to 0.5-8; and transalkylating reaction in catalyst bed layer at reaction temperature 350-550 deg.c, supercritical reaction pressure 3.1-12.0 MPa and space velocity 0.1-3 / hr to synthesize 2, 6-dimethyl naphthalene. The preparation process of the present invention has short production period, long catalyst service life and low production cost.

Description

technical field [0001] The invention relates to a method for preparing 2,6-dimethylnaphthalene. Background technique [0002] 2,6-dimethylnaphthalene (2,6-DMN) is an important raw material for the production of a new type of polyester polymer material polyethylene naphthalate (PEN). Naphthalene dicarboxylic acid generated after oxidation of 2,6-DMN is polymerized with ethylene glycol to obtain PEN. Compared with polyethylene terephthalate (PET), which is widely used at present, PEN has excellent properties such as higher mechanical strength, heat resistance, high chemical stability and good gas barrier properties. , packaging materials, instrumentation and aerospace and many other fields have broad application prospects. [0003] At present, 2,6-DMN is mainly extracted from raw materials such as coal tar and heavy aromatics produced by oil refining, or synthesized by multi-step chemical methods. Due to the low content of 2,6-DMN in these raw materials (about 0.1-1% 2,6-DM...

Claims

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Application Information

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IPC IPC(8): C07C15/24C07C6/12
CPCY02P20/54
Inventor 吴伟
Owner HEILONGJIANG UNIV
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