Method for synthesizing methyl heptenone from isopentenyl alcohol

A technology of methylheptenone and prenol, which is applied in chemical instruments and methods, preparation of organic compounds, carbon-based compounds, etc., can solve problems such as complex 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: 2019-01-18
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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  • Method for synthesizing methyl heptenone from isopentenyl alcohol
  • Method for synthesizing methyl heptenone from isopentenyl alcohol
  • Method for synthesizing methyl heptenone from isopentenyl alcohol

Examples

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Effect test

Embodiment 1

[0049] This example catalyzes the chlorination of prenol by zinc chloride to synthesize methylheptenone in N,N-dimethylformamide.

[0050]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

[0054] This example catalyzes the chlorination of isopentenol by zinc chloride to synthesize methylheptene in N,N-dimethylformamide.

[0055] 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

[0058] This example catalyzes the chlorination of prenol by zinc chloride to synthesize methylheptenone in N,N-dimethylformamide

[0059] 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 compo...

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Abstract

The invention provides a method for synthesizing methyl heptenone from isopentenyl alcohol. The method comprises the following steps: (1) reacting isopentenyl alcohol with concentrated hydrochloric acid in the presence of a catalyst A, splitting phase for the reacting liquid, washing and distilling the organic phase to obtain a chloro mixture of 1-chloro-3-methyl-2-butene and 3-chloro-3-methyl-1-butene; (2) directly condensing the chloro mixture with acetone in the presence of a catalyst B to obtain a single product methyl heptenone. According to the method, isopentenyl alcohol is efficientlychlorinated in the presence of metal inorganic salt functioning as a catalyst and concentrated hydrochloric acid functioning as a chlorinating agent; the chlorinating reaction liquid is split and simply distilled to obtain the chlorinated mixture, operation steps of isomerization, rectification and the like are not required; alkali solution is promoted by using N,N-dimethyl formamide as a condensation solvent, and a phase transfer catalyst is not required to be added, the condensation time is reduced, and the reaction yield is improved.

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 Applications(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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