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Ionic liquid catalyzed transalkylation process for preparing 2,6-dimethyl naphthalene

A technology of ionic liquid and dimethylnaphthalene, which is applied in the field of catalytic transfer alkylation of ionic liquid to prepare 2, can solve the problem of intensified dealkylation, isomerization and polyalkylation, difficult to significantly improve, and separation difficulties, etc. problems, to achieve the effect of no environmental pollution, good effect and wide adaptability of raw materials

Inactive Publication Date: 2011-09-14
HEILONGJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although by AlCl 3 Immobilization can solve the problem of difficult separation of catalyst and product and improve the selectivity of 2,6-DMN to a certain extent, but the heterogeneous reaction temperature using solid acid as catalyst is relatively high, and at the same time of catalytic transfer methylation, It also intensifies side reactions such as dealkylation, isomerization, disproportionation, and polyalkylation, and it is difficult to significantly improve the selectivity of 2,6-DMN, and the solid catalyst also has disadvantages such as easy deactivation due to carbon deposition.

Method used

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  • Ionic liquid catalyzed transalkylation process for preparing 2,6-dimethyl naphthalene
  • Ionic liquid catalyzed transalkylation process for preparing 2,6-dimethyl naphthalene
  • Ionic liquid catalyzed transalkylation process for preparing 2,6-dimethyl naphthalene

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Embodiment 1

[0026] A method for preparing 2,6-dimethylnaphthalene by catalyzed transfer alkylation of ionic liquid, with β-methylnaphthalene, 1,2,4,5-tetramethylbenzene and cyclohexane in a molar ratio of 1:1:12 Mix, add 47.8% of the ionic liquid catalyst accounting for the total weight of the mixed solution to the mixed solution, and carry out the transfer alkylation reaction at a temperature of 20 ° C under the protection of an inert gas. After 7 hours, the reaction ends, and the natural layering occurs after cooling to room temperature. The liquid is in the lower layer, and the upper layer reaction liquid is decanted to obtain 2,6-dimethylnaphthalene. The remaining ionic liquid can be reused, and the supernatant liquid is taken for qualitative and quantitative analysis of gas chromatography, and the conversion rate of β-methylnaphthalene and the selectivity of 2,6-dimethylnaphthalene are calculated by the area normalization method, See Table 1 (No. 1). The ionic catalyst is the combin...

Embodiment 2

[0028] The ionic liquid catalytic transfer alkylation described in embodiment 1 prepares the method for 2,6-dimethylnaphthalene, with β-methylnaphthalene, 1,2,4,5-tetramethylbenzene and cyclohexane with molar ratio 1 : 0.5: 12 mixing, adding 47.8% of the ionic liquid catalyst accounting for the total weight of the mixed solution in the mixed solution, at a temperature of 20 ° C, under the protection of an inert gas to carry out the transfer alkylation reaction, after 7 hours, the reaction is over, cooled to room temperature naturally Layering, the ionic liquid is in the lower layer, and the upper layer of the reaction solution is decanted to obtain 2,6-dimethylnaphthalene. The remaining ionic liquid can be reused, and the supernatant liquid is taken for qualitative and quantitative analysis of gas chromatography, and the conversion rate of β-methylnaphthalene and the selectivity of 2,6-dimethylnaphthalene are calculated by the area normalization method, See Table 1 (sequence n...

Embodiment 3

[0030]The ionic liquid catalytic transfer alkylation described in embodiment 1 prepares the method for 2,6-dimethylnaphthalene, with β-methylnaphthalene, 1,2,4,5-tetramethylbenzene and cyclohexane with molar ratio 1 : 1: 12 mixing, add in the mixed solution and account for the ionic liquid catalyst of 23.9 or 71.7% of the total weight of the mixed solution, at a temperature of 20°C, carry out the transalkylation reaction under the protection of an inert gas, after 7 hours, the reaction ends, and it is cooled to Natural layering at room temperature, the ionic liquid is in the lower layer, and the upper layer of the reaction solution is decanted to obtain 2,6-dimethylnaphthalene. The remaining ionic liquid can be reused, and the supernatant liquid is taken for qualitative and quantitative analysis of gas chromatography, and the conversion rate of β-methylnaphthalene and the selectivity of 2,6-dimethylnaphthalene are calculated by the area normalization method, See Table 1 (seria...

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Abstract

The ionic liquid catalyzed transalkylation process for preparing 2, 6-dimethyl naphthalene includes: mixing 2-methyl naphthalene or mixed methyl naphthalene, transalkylating agent and solvent in the molar ratio of 1 to (0.5-3) to 12; adding ionic liquid catalyst in 20-75 % of the total weight of the mixture liquid, and transalkylating reaction at the temperature of 20 deg.c to reflux temperature under the protection of inert gas for 2-11 hr to obtain 2, 6-dimethyl naphthalene. The present invention has simple technological path, reuse of the catalyst, no environmental pollution, greatly raised 2, 6-dimethyl naphthalene selectivity and lowered production cost.

Description

Technical field: [0001] The invention relates to a method for preparing 2,6-dimethylnaphthalene, in particular to a method for preparing 2,6-dimethylnaphthalene by using ionic liquid catalytic transfer alkylation. 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 chemical stability, heat resistance and radiation resistance, good gas barrier property, and high mechanical strength. It has broad application prospects in many fields such as electronic components, packaging materials, instruments and meters, and aerospace. [0003] At present, 2,6-DMN is mainly extracted from raw materials such as coal ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C6/08
CPCY02P20/584
Inventor 吴伟武光
Owner HEILONGJIANG UNIV
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