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Method for preparing 2,3,5-trimethylhydroquinone

A technology of trimethylphenol and p-benzoquinone, applied in the field of preparation 2, which can solve the problems of troublesome separation of product and solvent, excessive catalyst, high separation cost, etc.

Active Publication Date: 2011-06-29
SHANGHAI HEGNO PHARMA HLDG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] EP0387820 uses aliphatic alcohol with 12-18 carbon atoms as a solvent. Due to the high boiling point of the solvent, the product is not easy to separate from the solvent, and the energy consumption is high, so it is not suitable for industrial applications
[0008] EP127888 uses an aqueous solution of lithium copper chloride as a catalyst, the amount of the catalyst needs to be greatly excessive, and the preparation of the catalyst is relatively complicated, and a complex of trivalent copper needs to be prepared, and the catalyst preparation cost is relatively high
[0009] CN1319582 discloses using new carboxylic acids with 8-11 carbon atoms as solvents, especially neodecanoic acid as solvent, and neodecanoic acid has a higher boiling point, which also has the problem of troublesome separation of product and solvent and high separation cost
[0010] CN101113131A describes the ionic liquid composed of imidazole, quaternary ammonium, pyridinium cation and acid radical ion as the reaction solvent, directly distilled after the reaction, but a large amount of distillation residue is mixed with the ionic liquid, and the ionic liquid is difficult to apply mechanically directly, which is not suitable for industrial production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] In a 150 ml four-neck flask equipped with a condenser, a stirring paddle, a dropping funnel and a vent tube, add 80 grams of water, 17 grams of copper chloride dihydrate and 7 grams of anhydrous lithium chloride, and then add 0.68 grams of benzyl Triethylammonium chloride, stirred vigorously, heated to 40°C, passed oxygen through the glass tube, the flow rate was 300ml / min, began to drop 13.6g of molten 2,3,6-trimethylphenol, within 2 hours After the addition was completed, the reaction was performed for another 4 hours after the dropwise addition. After the reaction, the oil layer was directly taken for GC analysis, and the purity of 2,3,5-trimethylbenzoquinone was 93%. The oil phase was distilled under reduced pressure to obtain 13.6 g of 2,3,5-trimethylbenzoquinone with a yield of 90.0%, which was analyzed by GC again and the purity was 99.5%. MS: m / z 150 (M + )...

Embodiment 2

[0035] The 150 milliliter four-necked bottle equipped with condenser, stirring paddle, dropping funnel and ventilation tube was placed in the ultrasonic reactor, and 80 grams of water, 17 grams of copper chloride dihydrate and 7 grams of anhydrous lithium chloride were added, and then Add 0.68 g of benzyltriethylammonium chloride, stir vigorously, heat to 40°C, pass oxygen through the glass tube at a flow rate of 300 ml / min, turn on the ultrasonic wave at a frequency of 20KHz, and start to drop molten 2, Add 13.6 grams of 3,6-trimethylphenol within 2 hours, and react for another 4 hours after the dropwise addition. After the reaction, the oil layer was directly taken for GC analysis, and the purity of 2,3,5-trimethylbenzoquinone was 94%. The oil phase was distilled under reduced pressure to obtain 13.7 g of 2,3,5-trimethylbenzoquinone with a yield of 91.3%, which was analyzed by GC again and the purity was 99.6%.

Embodiment 3

[0037] The 150 milliliter four-necked bottle equipped with condenser, stirring paddle, dropping funnel and ventilation tube was placed in the ultrasonic reactor, and 80 grams of water, 17 grams of copper chloride dihydrate and 7 grams of anhydrous lithium chloride were added, and then Add 0.6 g of PEG300, stir vigorously, heat to 40°C, pass oxygen through the glass tube, the flow rate is 300 ml / min, turn on the ultrasonic wave at the same time, the ultrasonic frequency is 20KHz, start to drop the molten 2,3,6-trimethyl 13.6 grams of phenol was added within 2 hours, and then reacted for 4 hours after the dropwise addition. After the reaction, the oil layer was directly taken for GC analysis, and the purity of 2,3,5-trimethylbenzoquinone was 94%. The oil phase was distilled under reduced pressure to obtain 13.8 g of 2,3,5-trimethylbenzoquinone with a yield of 92.0%, which was analyzed by GC again and the purity was 99.7%.

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PUM

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Abstract

The invention discloses a method for preparing 2,3,5-trimethylhydroquinone, which comprises oxidizing 2,3,6-trimethylphenol with pure oxygen or oxygen-enriched gas in water serving as a reaction medium in the presence of a catalyst consisting of copper halide and lithium halide and a phase transfer catalyst to obtain 2,3,5-trimethylhydroquinone. In the method disclosed by the invention, organic solvent is not added, the production safety is ensured, the operation is simplified, the energy cost is greatly reduced, the yield of the obtained product is over 90 percent, and the purity of the obtained product is over 99.5 percent. Thus, the method is suitable for industrial mass production.

Description

technical field [0001] The invention relates to a method for preparing 2,3,5-trimethyl-p-benzoquinone. Background technique [0002] 2,3,5-Trimethyl-p-benzoquinone is an important intermediate in the synthesis of α-tocopherol (vitamin E), and 2,3,6-Trimethylphenol is oxidized to 2,3,5-Trimethyl-p- There are many published methods for benzoquinones. In the disclosed method, inorganic oxidants such as potassium permanganate, manganese dioxide, and lead oxide are used, which must consume a stoichiometric amount of catalyst, and produce a contaminated waste liquid with more reduced metals, which requires higher cost for disposal or regeneration. [0003] US3796732 describes the use of copper chloride as a catalyst and DMF as a reaction solvent to carry out a homogeneous reaction. The recovery industrial production of the catalyst and DMF is very troublesome, and the recovery cost is relatively high. [0004] CN1024188 describes the use of copper chloride and lithium chloride ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C50/02C07C46/08
Inventor 刘德铭鲁向阳密福远
Owner SHANGHAI HEGNO PHARMA HLDG
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