A kind of preparation method of 4-acetoxy-2-methyl-2-butenal

A technology of acetoxy and crotonaldehyde, applied in the field of preparation of 4-acetoxy-2-methyl-2-butenal, which can solve the problems of consumption price, a large number of by-products, unstable intermediates, etc.

Active Publication Date: 2021-07-23
WANHUA CHEM GRP CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The preparation technology of pentacarbon aldehyde mainly is divided into three classes at present: 1) is starting raw material with oxirane, and major shortcoming is: can produce a large amount of unstable intermediates, have relatively great influence on the storage of intermediates and the safety of reaction High requirement; 2) take dimethoxyacetone as starting raw material, main disadvantage is: route is long, and yield is lower, produces a large amount of by-products; 3) taking isoprene and sodium hypochlorite as starting raw material, mainly The disadvantage is: the original process route will produce a large amount of waste water, and the pollution is serious
This method also has an unstable intermediate 29, and a large amount of expensive organic phosphine reagents are consumed in the route

Method used

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  • A kind of preparation method of 4-acetoxy-2-methyl-2-butenal
  • A kind of preparation method of 4-acetoxy-2-methyl-2-butenal
  • A kind of preparation method of 4-acetoxy-2-methyl-2-butenal

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Experimental program
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Effect test

Embodiment 1

[0064] (1) Preparation of prenol acetate: Add 20 mol of deionized water, 1.1 mol of anhydrous sodium acetate, and 0.02 mol of benzyltriethylammonium iodide into a 2L glass three-necked flask, and stir with a glass rod until the solid is dissolved in water After all the solution is dissolved, the temperature is raised to 45°C, 1 mol of chloroisoamylene is added to the flask, the high-speed shear stirring motor is turned on, and the rotation speed is set at 5000 rpm to start the reaction. After reacting for 4 hours, the liquid in the flask was cooled and transferred to a 2L separatory funnel. After standing for 2 hours, the liquid was separated, and the upper organic phase was taken for gas chromatography analysis. The conversion rate of isopentyl chloride was 95.56%. The enol acetate selectivity was 98.55%. Use a packed column with a theoretical plate number of 25 to rectify the organic phase and remove the solvent from the reaction solution under the condition of 1KPa. The ref...

Embodiment 2

[0068] (1) Preparation of prenol acetate: Add 20 mol of deionized water, 1.1 mol of anhydrous sodium acetate, and 0.02 mol of trioctylmethylammonium iodide in a 2L glass three-necked flask, and stir with a glass rod until the solid is dissolved in water After all dissolved, raise the temperature to 35°C, add 1mol chloroisoamylene into the flask, turn on the high-speed shear stirring motor, set the rotation speed to 5000rpm, and start the reaction. After reacting for 4 hours, the liquid in the flask was cooled and transferred to a 2L separatory funnel. After standing for 2 hours, the liquid was separated, and the upper organic phase was taken for gas chromatography analysis. The conversion rate of isopentyl chloride was 96.15%. The selectivity of enol acetate was 97.93%. Use a packed column with a theoretical plate number of 25 to rectify the organic phase and remove the solvent from the reaction solution under the condition of 1KPa. The reflux ratio is 1:1, and the fraction at...

Embodiment 3

[0071] (1) Preparation of prenol acetate: Add 40 mol of deionized water, 1.2 mol of anhydrous lithium acetate, and 0.05 mol of tetrabutylammonium iodide into a 2L glass three-necked flask, and stir with a glass rod until the solid is completely dissolved in water Afterwards, the temperature was raised to 40° C., 1 mol of chloroisoamylene was added into the flask, the high-speed shear stirring motor was turned on, and the rotation speed was set to 5000 rpm to start the reaction. After reacting for 4.5 hours, the liquid in the flask was cooled and transferred to a 2L separatory funnel. After standing for 2 hours, the liquid was separated, and the upper organic phase was taken for gas chromatography analysis, and the conversion rate of isoamyl chloride was 97.82%. The selectivity of pentenol acetate is 95.86%. Use a packed column with a theoretical plate number of 10 to rectify the organic phase and remove the solvent from the reaction solution under the condition of 0.8KPa. The ...

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Abstract

The invention discloses a preparation method of 4-acetoxy-2-methyl-2-butenal. The method comprises the following steps: (1) under the catalysis of a phase-transfer catalyst, the chlorinated isopentene reacts with acetate to generate prenol acetate; (2) under the catalysis of selenium dioxide, the step (1) Oxidation of prenol acetate obtained to obtain 4-acetoxy-2-methyl-2-butenal. The method uses chlorinated isopentene as a starting material, which is a common fine chemical intermediate, is cheap and easy to obtain, does not need to use noble metal catalysts in the reaction process, has low cost, short synthetic route, simple operation, and little environmental pollution . It is an effective synthetic route.

Description

technical field [0001] The invention relates to a preparation method of 4-acetoxy-2-methyl-2-butenal, which belongs to the field of chemical intermediate preparation. Background technique [0002] 4-Acetoxy-2-methyl-2-butenal (hereinafter referred to as "penta-carbon aldehyde") is an important intermediate for the synthesis of vitamin A. Due to the importance of five-carbon aldehyde in the synthesis of vitamin A industry, the synthesis process of five-carbon aldehyde has been a research hotspot for a long time. [0003] The preparation technology of pentacarbon aldehyde mainly is divided into three classes at present: 1) is starting raw material with oxirane, and major shortcoming is: can produce a large amount of unstable intermediates, have relatively great influence on the storage of intermediates and the safety of reaction High requirement; 2) take dimethoxyacetone as starting raw material, main disadvantage is: route is long, and yield is lower, produces a large amount...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C67/04C07C67/29C07C69/145
CPCC07C67/04C07C67/29C07C69/145
Inventor 程晓波胡展吕英东张涛黎源
Owner WANHUA CHEM GRP CO LTD
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