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A kind of preparation method of 1,4-dimethylnaphthalene

A technology of dimethylnaphthalene and diphenylphosphine, which is applied in the field of preparation of 1,4-dimethylnaphthalene, can solve the problems of difficult separation of isomers, harsh reaction conditions, expensive materials and the like, and achieves production cost Low, short synthetic route, single reaction site effect

Active Publication Date: 2020-06-30
LIER CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the invention of the present invention is: when adopting the methylation route to synthesize 1,4-dimethylnaphthalene, the separation of isomers is difficult, industrialization is difficult, and has no industrial value, while the ring-closing route synthesizes 1,4-dimethylnaphthalene For naphthalene, some of the reaction conditions are harsh, the materials involved are expensive, highly toxic, high-risk, the total yield is not high, the cost is high, and the industrialization is difficult. A preparation method for 1,4-dimethylnaphthalene is provided

Method used

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  • A kind of preparation method of 1,4-dimethylnaphthalene
  • A kind of preparation method of 1,4-dimethylnaphthalene
  • A kind of preparation method of 1,4-dimethylnaphthalene

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] First, add 39.4g (0.2mol) of 1,4-dichloronaphthalene, 220mg of bis(triphenylphosphine) nickel dichloride, and 200mL of trimethylbenzene to the reaction flask; then, under the protection of nitrogen, control under -10℃ stirring , Slowly add 134mL (0.4mol) of methylmagnesium chloride tetrahydrofuran solution, after dripping, heat up at 150℃ to react for 16h, distill to recover the solvent, then add 100mL petroleum ether and 120mL water to extract the phases; distill the organic phase obtained from the extraction to recover petroleum Ether, further water pump vacuum distillation collects the 165°C fraction, which is 1,4-dimethylnaphthalene, a total of 28.7g of product is obtained, the content is 98%, and the yield is 90.1%. 1 H NMR (400MHz, deuterated acetone), 7.975 (dd, J=6.4Hz, 3.2Hz, 2H), 7.498 (dd, J=6.4Hz, 3.2Hz, 2H), 7.173 (s, 2H), 2.590 (s , 6H).

[0034] The content is determined by the area normalization method.

Embodiment 2

[0036] First, add 57.2g of 1,4-dibromonaphthalene, 200mg of bis(triphenylphosphine) nickel dichloride, and 200mL of xylene into the reaction flask; then under the protection of nitrogen, add slowly while stirring at -10℃. Methylmagnesium bromide 2-methyltetrahydrofuran solution 167mL, after dripping, heat up to 95℃ and react for 18h, distill to recover the solvent, then add 100mL petroleum ether and 120mL water to extract the phases; distill the organic phase obtained by extraction and separation to recover petroleum ether, Further, the 165°C fraction was collected by vacuum distillation with a water pump, which is 1,4-dimethylnaphthalene, and a total of 30 g of product was obtained, the content was 98%, and the yield was 94.2%.

[0037] According to the method of Example 2, the catalyst and temperature parameters were screened, and the results are shown in Table 1 below:

[0038] Table 1

[0039] catalyst temperature Solvent Format reagent dosage Yield Example 2 Bis(triphenylp...

Embodiment 10

[0044] Replace the reaction flask with nitrogen and add NiCl to the flask 2 ·6H 2 O 0.1g, ethanol 1mL stirred to obtain a green clear liquid; then 200mL of toluene and 0.23g of triphenylphosphine were added, and stirred to obtain a dark green liquid; then 57.2g of 1,4-dibromonaphthalene was added, and slowly dripped under stirring at -10℃ Add 167mL of methylmagnesium bromide 2-methyltetrahydrofuran solution. After dripping, heat up at 105℃ to react for 12h, distill to recover the solvent, then add 100mL of petroleum ether and 120mL of water to extract the phases; the organic phase is distilled to recover the petroleum ether, and the pump depressurizes The 165°C fraction collected by distillation is 1,4-dimethylnaphthalene. A total of 30.3g of product is obtained, the content is 98%, and the yield is 95.1%.

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Abstract

The invention discloses a method for preparing 1,4-dimethylnaphthalene and belongs to the field of organic synthesis. The method aims at solving the problems during the synthesis of the 1,4-dimethylnaphthalene by a methylation route that isomers are high in separation difficulty, difficult in industrialization and free of industrialization value, and the problems during the synthesis of the 1,4-dimethylnaphthalene by a ring-closing route that partial reaction conditions are harsh, involved materials are high in price, high in toxicity and high in risk, the total yield is low, the cost is high, and the difficulty of industrialization is high. According to the method, the 1,4-dimethylnaphthalene is prepared from 1,4-dihalonaphthalene and a methyl magnesium halide Grignard reagent, which serve as main raw materials, in the presence of a nickel-phosphonium complex and a solvent. The method disclosed by the invention has the advantages of readily available raw materials, short synthesis route, mild reaction conditions and low cost, is applicable to industrial production and application and has a relatively high industrial application value. Meanwhile, the product prepared by the method is high in purity, stable in quality and high in yield and content and has a relatively high economic value.

Description

Technical field [0001] The invention relates to the field of chemical engineering, especially the field of organic synthesis, and specifically relates to a method for preparing 1,4-dimethylnaphthalene. Background technique [0002] 1,4-Dimethylnaphthalene is a high value-added fine chemical product, mainly used in the field of plant growth regulators and fluorescent whitening agents. In addition, 1,4-naphthalenedicarboxylic acid obtained by oxidation of 1,4-dimethylnaphthalene is an important intermediate in the fields of pigments, resins, fuels, and medicine. It can be used as a mixed material additive for clothing materials and high-strength container materials. Other materials (References, Fuels and Dyeing, Liu Bing et al., 2017, Volume 54 and page 36). [0003] At present, the literature reports on the synthesis route of 1,4-dimethylnaphthalene mainly include two routes: methylation route and cyclization route. Among them, for the methylation route, the contents disclosed in ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C15/24C07C1/32
CPCC07C1/326C07C2531/24C07C15/24
Inventor 曾柏清任杰彭启才周志成范谦
Owner LIER CHEM CO LTD