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A method for synthesizing methylheptenone by isopentenol

A technology of methyl heptenone and prenol, which is applied in chemical instruments and methods, preparation of organic compounds, carbon-based compounds, etc., can solve problems such as complicated side reactions, difficult product purification, and excessive waste, and achieve Effect of reducing reaction time, increasing condensation reaction yield, and improving solubility

Active Publication Date: 2021-09-03
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] To sum up, although methyl heptenone has been synthesized by various methods at present, and some synthetic routes have achieved large-scale production, these synthetic routes generally have disadvantages such as more three wastes, complicated side reactions, and difficult product purification; Therefore, there is still a need to develop a new synthesis route of methyl heptenone, overcome the shortcomings of existing routes, and synthesize methyl heptenone products more efficiently, environmentally friendly and atom-economically

Method used

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  • A method for synthesizing methylheptenone by isopentenol
  • A method for synthesizing methylheptenone by isopentenol
  • A method for synthesizing methylheptenone by isopentenol

Examples

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Effect test

Embodiment 1

[0048] This example catalyzes the chlorination of prenol by zinc chloride to synthesize methylheptenone in N,N-dimethylformamide.

[0049]Under nitrogen protection, 60.0 mL of concentrated hydrochloric acid (38%, 0.74 mol), 0.27 g of zinc chloride (0.002 mol) and 17.2 g of prenyl alcohol (0.2 mol) were successively added into the three-necked flask. Put in a magnetic stirrer and assemble a reflux condenser, put the three-neck flask in an oil bath at 50°C, stir the reaction rapidly, and the reaction solution gradually becomes turbid from a homogeneous phase. After 3 hours, GC detected the organic phase, and the conversion rate of prenol was >98%. The reaction was stopped, the temperature was lowered, and the phases were separated. After washing the organic phase with saturated aqueous sodium bicarbonate solution and deionized water, the product 19.5 g, yield 92.2%. Product composition: 1-chloro-3-methyl-2-butene (91.1 wt%), 3-chloro-3-methyl-1-butene (7.6 wt%), dichloride (1.3...

Embodiment 2

[0053] This example catalyzes the chlorination of isopentenol by zinc chloride to synthesize methylheptene in N,N-dimethylformamide.

[0054] Under the protection of nitrogen, concentrated hydrochloric acid (81.4 mL, 38%, 1.0 mol), zinc chloride (27.3 mg, 0.0002 mol) and isopentenol (17.2 g, 0.2 mol) were successively added into the three-necked flask. Put a magnetic stirrer in the three-necked flask, and after it is equipped with a reflux condenser, put the three-necked flask in an oil bath at 40°C, and react under rapid stirring. During the reaction, the reaction solution gradually becomes turbid from a homogeneous phase. After 1 hour, GC detects the organic phase, and the conversion rate of prenol is >98%. Stop the reaction, lower the temperature, separate the liquid using a separatory funnel, wash the organic phase with saturated aqueous sodium bicarbonate solution and deionized water successively, and distill under reduced pressure to obtain Product 19.2g, yield 90.0%. P...

Embodiment 3

[0057] This example catalyzes the chlorination of prenol by zinc chloride to synthesize methylheptenone in N,N-dimethylformamide.

[0058] Under nitrogen protection, concentrated hydrochloric acid (62.0 mL, 10%, 0.2 mol), zinc chloride (2.7 g, 0.02 mol) and isopentenol (17.2 g, 0.2 mol) were sequentially added into the three-necked flask. Put a magnetic stirrer in the three-necked flask, and after it is equipped with a reflux condenser, put the three-necked flask in an oil bath at 70°C, and react under rapid stirring. During the reaction, the reaction solution gradually becomes turbid from a homogeneous phase. After 3 hours, GC detected the organic phase, and the conversion rate of prenol was >98%. Stop the reaction, lower the temperature, separate the liquid using a separatory funnel, wash the organic phase with saturated aqueous sodium bicarbonate solution and deionized water successively, and distill under reduced pressure to obtain Product 17.6g, yield 83.3%. Product comp...

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Abstract

The invention provides a method for efficiently synthesizing methyl heptenone from prenol. The method comprises: (1) prenol is reacted with concentrated hydrochloric acid under the action of catalyst A, the reaction liquid is phase-separated after the reaction, and the organic phase is distilled after washing to obtain 1-chloro-3-methyl-2-butene and A chlorinated mixture of 3-chloro-3-methyl-1-butene; (2) the above-mentioned chlorinated mixture is directly condensed with acetone under the action of catalyst B to obtain a single product, methyl heptenone. The present invention adopts metal inorganic salt as a catalyst and concentrated hydrochloric acid as a chlorination agent to efficiently realize the chlorination of prenyl alcohol; the chlorination reaction liquid is separated and simply distilled to obtain a chlorinated mixture without the need for isomerization conversion and purification. Operation steps such as distillation and purification; use N,N-dimethylformamide as the condensation reaction solvent, which promotes the dissolution of the base, does not need to add a phase transfer catalyst, reduces the condensation reaction time, and improves the reaction yield.

Description

technical field [0001] The invention belongs to the field of flavors and fragrances in fine chemical industry, and in particular relates to a method for efficiently synthesizing methylheptenone from prenyl alcohol. Background technique [0002] Methylheptenone has a fresh and fruity aroma and is a food flavor allowed by the national standard. It can be used to prepare banana, pear and berry flavors; in addition, methylheptenone is also an important synthetic intermediate and can be used for linalool , citral, pseudoionone and other spices synthesis. At present, the market demand for methyl heptenone is strong. In view of the importance of methyl heptenone, many synthetic routes of methyl heptenone have been reported, which can be roughly divided into acetylene-acetone method, isobutylene-formaldehyde method and isoprene method. [0003] The acetylene-acetone method is the earliest industrialized method of methyl heptenone (DE2126356, GB788301, GB888999, DE1137433). This me...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C45/68C07C49/203
CPCC07C17/16C07C45/68C07C49/203C07C21/04
Inventor 黄文学沈稳于斌成张永振王明永
Owner WANHUA CHEM GRP CO LTD
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