Synthetic method of methyl cyclopentenolone

A technology of methyl cyclopentenol ketone and synthesis method, which is applied in the preparation of carbon-based compounds, chemical instruments and methods, preparation of organic compounds, etc. higher question

Pending Publication Date: 2020-12-29
SHANGHAI INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Finally, MCP is obtained after chlorination, hydrolysis, and decarboxylation, but the temperature control requirements are too high during the reaction process, and a large amount of chlorine gas is generated when the solvent

Method used

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  • Synthetic method of methyl cyclopentenolone
  • Synthetic method of methyl cyclopentenolone
  • Synthetic method of methyl cyclopentenolone

Examples

Experimental program
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preparation example Construction

[0030] A synthetic method of methylcyclopentenolone, the method may further comprise the steps:

[0031] (1) Control reaction system at pH=2-7, preferably pH=3-6, temperature is 45-70 DEG C, under preferred 50-65 DEG C, monitor dimethylamine hydrochloride, formaldehyde aqueous solution and 2 with online infrared instrument -Methylfuran reaction generates N,N-dimethyl-5-methylfurfurylamine reaction process; wherein, the mol ratio of dimethylamine hydrochloride and formaldehyde is (1-1.2):1, preferably (1- 1.02):1; the mass concentration of formaldehyde aqueous solution is 37-40ωt%; the molar ratio of dimethylamine hydrochloride to 2-methylfuran is (1-1.3):1. Preferred (1.05-1.07):1.

[0032] When detecting the content of 2-methylfuran in the reaction solution<0.55%, then acidify the reaction system pH<1 with industrial hydrochloric acid with a concentration of 5-37ωt%, preferably 30ωt%, at 60-100°C, preferably 70-100°C, The time is 1-4h, preferably 2-3h to obtain the product ...

Embodiment 1

[0036] A synthetic method of methylcyclopentenolone, the method may further comprise the steps:

[0037] (1) Add 44.85g (0.55mol) dimethylamine hydrochloride and 19.59g (1.09mol) water into a 500ml four-neck flask, control the temperature to 50°C, add 42.08g (37-40%, 0.54mol) formaldehyde , adjust the pH of the reaction solution to 4.5, and start to add 42.69g (0.52mol) of 2-methylfuran dropwise after 0.5h of reaction;

[0038] Leverage React IR TM 15 Monitor the reaction solution and find that the content of 2-methylfuran is <0.55%, while the mass content of N,N-dimethyl-5-methylfurfurylamine is 46.24%. Then dilute hydrochloric acid is added to adjust the pH to 0.95, and the temperature is raised to 70 ℃, after 3 hours of reaction, adjust the pH to 12.5 with sodium hydroxide solution, and react at a temperature of 75-80℃ for 0.5 hours to obtain 2-(dimethylamino)-3-methyl-2-cyclopentene-1- The ketone content is 95.57%. After extraction, concentration and recovery of the sol...

Embodiment 2

[0042] A synthetic method of methylcyclopentenolone, the method may further comprise the steps:

[0043] (1) Add 44.85g (0.55mol) dimethylamine hydrochloride and 19.59g (1.09mol) water into a 500ml four-neck flask, control the temperature to 60°C, add 42.08g (37-40%, 0.54mol) formaldehyde , adjust the pH of the reaction solution to 4.5, and start to add 42.69g (0.52mol) of 2-methylfuran dropwise after 0.5h of reaction,

[0044] Leverage React IR TM 15 Monitor the reaction solution and find that the content of 2-methylfuran is <0.55%, while the content of N,N-dimethyl-5-methylfurfurylamine is 48.27%, then add dilute hydrochloric acid, adjust the pH to 0.95, and heat up to 80°C , after reacting for 3 hours, adjust the pH to 12.5 with sodium hydroxide solution, and react at a temperature of 75-80°C for 0.5 hours to obtain 2-(dimethylamino)-3-methyl-2-cyclopenten-1-one The content is 95.61%. After extraction, concentration and recovery of the solvent, 2.21g of the front fractio...

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Abstract

The invention relates to a preparation method of methyl cyclopentenolone, which comprises the following steps: (1) controlling the pH value and temperature of a reaction system, and reacting a dimethylamine hydrochloride, a formaldehyde aqueous solution and 2-methyl furan to generate N, N-dimethyl-5-methyl furfuryl amine; (2) when it is monitored that the content of the 2-methyl furan is not reduced any more, adjusting the pH value of the reaction solution to be less than 1 by using an acid solution, and reacting to obtain a product 1-dimethyl amino-2, 5-hexanedione; and (3) adjusting the pH value of the reaction solution to 12-13 by using an alkali, reacting, extracting the reaction solution, concentrating to recover the solvent, and rectifying to obtain a product 2-(dimethylamino)-3-methyl-2-cyclopentene-1-one; and (4) mixing 2-(dimethylamino)-3-methyl-2-cyclopentene-1-one with hydrochloric acid, reacting, hydrolyzing, crystallizing and purifying to obtain methyl cyclopentenolone, and concentrating and recycling a reaction mother liquor Compared with the prior art, the method has the advantages that remote and automatic operation is facilitated, wastewater treatment is reduced, and the raw material dimethylamine hydrochloride can be reused.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a method for synthesizing methylcyclopentenolone. Background technique [0002] Methylcyclopentenolone is usually called MCP (Methyl Cyclopentenolone). Methylcyclopentenolone is a natural substance that exists in maple trees, beech trees (beech family), tobacco and roasted coffee. The appearance is white crystalline solid. MCP is called "maple lactone" because of its prominent sweet aroma of maple syrup, strong burnt and sweet aroma, and taste of burnt sweetness. MCP was first extracted from wood acetic acid obtained by dry distillation of beech trees by J. Meyerfeld in 1912. It was later identified as MCP. The structural formula is as follows: [0003] [0004] There are also reports that it can be extracted from pyrolysis products of wood and carbohydrates. MCP is known as "maple lactone" because of its prominent sweet aroma of maple syrup, strong burnt and sweet aroma, a...

Claims

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Application Information

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IPC IPC(8): C07C45/64C07C49/573C07C221/00C07C225/06C07C225/20C07D307/52
CPCC07C45/64C07C221/00C07D307/52C07C2601/10C07C225/06C07C225/20C07C49/573
Inventor 毛海舫袁嘉成章平毅赵韵刘吉波芮姣李萧磊张驰原王洪朝徐露徐雨生焦炳熹
Owner SHANGHAI INSTITUTE OF TECHNOLOGY
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