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Preparation method of benzofuran-2-(3H)-ketone

A technology of benzofuran and o-hydroxyphenylacetic acid, which is applied in the field of preparation of benzofuran-2--one, can solve the problems of reduced yield, reduced yield, environmental pollution, etc., and achieves a small degree of environmental pollution and avoids raw materials Effect of carbonization and low acidity of wastewater

Inactive Publication Date: 2011-04-06
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0007] But because the above-mentioned reaction system is a solid-liquid two-phase system, it is difficult to control the contact time of the raw material and the concentrated sulfuric acid when the dehydrating agent concentrated sulfuric acid is added dropwise, which will easily cause the carbonization of the raw material o-hydroxyphenylacetic acid, thereby reducing the yield. Strong oxidation and strong acidity also increase the side reactions of the reaction, which further reduces the yield; at the same time, the use of concentrated sulfuric acid also has serious corrosion of equipment and pollution to the environment after discharge.

Method used

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  • Preparation method of benzofuran-2-(3H)-ketone
  • Preparation method of benzofuran-2-(3H)-ketone
  • Preparation method of benzofuran-2-(3H)-ketone

Examples

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Effect test

Embodiment 1

[0036] Add 0.3mol o-hydroxyphenylacetic acid and 3mol toluene into a 500ml three-necked flask, install a water separator, turn on the stirrer and heat the three-necked flask, set the stirring speed to 700r / min, when the temperature of the liquid in the three-necked flask rises to Increase the stirring speed to 850r / min at 60°C, add 0.75ml of dilute sulfuric acid with a concentration of 8mol / L dropwise to the three-necked flask at a speed of 0.15ml / min, and reduce the stirring speed to the speed before the dropwise addition , the temperature of the mixture in the there-necked flask was raised to 135°C for 6 hours, and then the reaction was terminated. After the reaction solution was cooled to room temperature, it was filtered. The filtrate was washed with saturated sodium bicarbonate solution and water successively, and then dried and desolvated under reduced pressure to obtain the target product, the product The purity was 98.3%, and the yield was 99.2%.

Embodiment 2～ Embodiment 9

[0038] The preparation process is the same as in the examples, and the specific process parameters, product purity and yield are listed in Table 1.

[0039] The processing parameter of table 1 embodiment 2-9 and product purity and yield

[0040]

[0041]

[0042] Process parameter and product purity and yield of continued table 1 embodiment 2-9

[0043]

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Abstract

The invention provides a preparation method of benzofuran-2-(3H)-ketone, comprising: under the stirring state and in the presence of dilute sulphuric acid, carrying out intramolecular esterification reaction on 2-hydroxyphenylacetic acid in water-carrying agent containing benzene rings at the temperature of 100-160 DEG C; in the reaction process, causing azeotrope formed by the water-carrying agent and water generated by reaction to enter a water knockout drum after condensation reflux; forming an aqueous layer and an oil layer in the water knockout drum; removing the aqueous layer; causing the oil layer to flow back to a mixed system of the 2-hydroxyphenylacetic acid and dilute sulphuric acid; and after reaction ends, obtaining the benzofuran-2-(3H)-ketone, wherein the concentration of the dilute sulphuric acid is 2-9 mol / L, and the molar ratio of sulphuric acid to the 2-hydroxyphenylacetic acid is 30-110:1. By utilizing the method provided by the invention to prepare the benzofuran-2-(3H)-ketone, the yield is higher.

Description

technical field [0001] The invention relates to the field of fungicides, in particular to a preparation method of benzofuran-2-(3H)-one. Background technique [0002] Azoxystrobin, whose structure is shown in formula I, is a methyl methacrylate fungicide, which is effective against almost all fungal diseases such as powdery mildew, rust, glume blight, net spot, downy mildew, rice blast, etc. All have good activity. Azoxystrobin is widely used in stem and leaf spray and seed treatment, and can also be used for soil treatment, mainly for bactericidal treatment of grains, fruit trees and vegetables. Azoxystrobin is an environmentally friendly fungicide that is safe to crops, has no phytotoxicity, and will not pollute groundwater when used at the recommended dose. [0003] [0004] Benzofuran-2-(3H)-one, whose structure is shown in formula II, is an important intermediate for the synthesis of azoxystrobin. In the existing production technology, the following three methods ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/83B01J27/02
Inventor 姚如杰金海琴周垂龙刘丹杨建川胡捷
Owner CHONGQING UNISPLENDOUR CHEM
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