Maleic hydrazide preparation method

A technology of maleic hydrazide and hydrazine hydrate, applied in the direction of organic chemistry, can solve the problems of high residual hydrazine of maleic hydrazide, incomplete reaction, low conversion rate of raw materials and low product yield, and achieve low cost and high quality , Reasonable effect of synthetic process

Inactive Publication Date: 2016-06-22
LIANYUNGANG JINDUN AGROCHEMICAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Due to the incomplete reaction of the traditional method, the low conversion rate of raw materials and low product yield, the residual hydrazine of maleic hydrazide is very high, and it is difficult to meet the above requirements, making it difficult for domestic products to meet the requirements of the international market. Therefore, it is very hopeful that there will be more A suitable method to improve the conversion rate of raw materials, product yield and product quality, and reduce the amount of residual hydrazine

Method used

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  • Maleic hydrazide preparation method

Examples

Experimental program
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Effect test

Embodiment 1

[0020] In a 1000ml four-neck round bottom flask equipped with mechanical stirring, thermometer and condenser tube, add 250g of water, 44g of concentrated sulfuric acid and 44ml of hydrazine hydrate, and react with 0.8g of lanthanum trifluoromethanesulfonate at 30-40°C for 30 minutes Then add 100g of maleic anhydride, heat up to 80-90°C and react for 1 hour, cool down to 40-50°C, add 80ml of 30% sodium hydroxide solution, neutralize to pH 6.5, filter, wash with water, and dry to obtain maleic hydrazide 98.3g (mp: 306-307°C, yield 96.7%).

Embodiment 2

[0022] In a 1000ml four-neck round bottom flask equipped with mechanical stirring, thermometer and condenser, add 250g of water, 55g of concentrated sulfuric acid and 44ml of hydrazine hydrate, 4g of lanthanum trifluoromethanesulfonate and react at 30-40°C for 30 minutes Add 125g of maleic anhydride, heat up to 90-100°C for 5 hours, cool down to 40-50°C, add 100ml of 30% sodium hydroxide solution, neutralize to pH 6.5, filter, wash with water, and dry to obtain maleic hydrazide 98.5 g (mp: 306-307°C, yield 96.9%).

Embodiment 3

[0024] In a 1000ml four-neck round bottom flask equipped with mechanical stirring, thermometer and condenser tube, add 250g of water, 66g of concentrated sulfuric acid and 44ml of hydrazine hydrate, 8g of lanthanum trifluoromethanesulfonate and react at 30-40°C for 30 minutes Add 150g of maleic anhydride, raise the temperature to 110-120°C for 10 hours, cool down to 40-50°C, add 120ml of 30% sodium hydroxide solution, neutralize to pH 6.5, filter, wash with water, and dry to obtain maleic hydrazide 98.8 g (mp: 306-307°C, yield 97.2).

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Abstract

The invention discloses a preparation method of maleic hydrazide. The maleic hydrazide is obtained by heating hydrazine hydrate and dilute sulfuric acid under the action of a rare earth compound catalyst, then adding maleic anhydride for ring closure reaction, and finally adding an inorganic base for neutralization. Since the present invention adds a rare earth trifluoromethanesulfonate catalyst in the reaction, and neutralizes it with an inorganic base after the reaction, the raw material hydrazine hydrate and maleic anhydride are reacted more completely. On the one hand, the maleic acid The hydrazine yield has been improved by more than 10%, and on the other hand, the residual hydrazine of maleic hydrazide is controlled below 2ppm, which has reached the international standard; the synthesis process of the present invention is more reasonable, has low cost, high quality, and is more suitable for industrial production .

Description

technical field [0001] The invention relates to a method for preparing a selective and temporary plant growth inhibitor maleic hydrazide, which belongs to the field of chemical preparation. Background technique [0002] Maleic hydrazide, referred to as MH, also known as Yiyadan, the chemical name is maleic hydrazide, which is a selective and temporary plant growth inhibitor. The agent can enter the plant through the cuticle of the leaf and can inhibit the Cell division and reduction of light and action, thereby strongly inhibiting the formation of buds and stem growth, improving cold resistance, and inhibiting the growth of tobacco axillary buds and the germination of potatoes, potatoes, onions, etc. during storage. [0003] At present, the process route for synthesizing maleic hydrazide is mainly prepared by reacting maleic anhydride and hydrazine hydrate in solvents such as water, ethanol, acetic acid and sulfuric acid respectively. [0004] [0005] Considering the yi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D237/16
Inventor 石卫兵戴翠红
Owner LIANYUNGANG JINDUN AGROCHEMICAL CO LTD
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