Method for preparing maleichydrazide

Abstract

The invention relates to a method for preparing maleichydrazide of a plant growth inhibitor, which is characterized by comprising the following steps of: reacting concentrated sulfuric acid with hydrazine hydrate to form a hydrazine sulfate aqueous solution; then adding organic aromatic acid as a catalyzer to react with maleic anhydride under refluxing under the condition of temperature rise; adding inorganic base to neutralize until the pH is 5.0-7.0; and rinsing with water at room temperature to remove hydrazine residues to obtain the maleichydrazide. The invention has safe and convenient operation and high yield, and the product quality meets the international standards, and thereby, the invention is extremely suitable for industrial production.

Description

technical field

[0001] The invention relates to a preparation method of maleic hydrazide, a selective and temporary plant growth inhibitor. 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 yield and manufacturing cost, sulfuric acid is mostl...

Examples

Embodiment 1

[0022] Preparation of maleic hydrazide

[0023] In a 1000ml four-necked round bottom flask equipped with mechanical stirring, thermometer and condenser, add 220g of water, 44g of concentrated sulfuric acid and 44ml of hydrazine hydrate, 5g of benzoic acid react at 30-40°C for 30 minutes, then add 100g of butene Diacid anhydride, heat up to 95°C for 3 hours, cool down to 30°C, add 76ml of 30% sodium hydroxide solution, neutralize to pH 6.0, filter, wash with water, and dry to obtain 97.0g of maleic hydrazide (mp: 306-307°C, Yield .95.4%).

Embodiment 2

[0025] In a 1000ml four-neck round bottom flask equipped with mechanical stirring, thermometer and condenser tube, add 220g of water, 44g of concentrated sulfuric acid and 44ml of hydrazine hydrate, and add 5.8g of o-toluic acid after reacting at 30-40°C for 30 minutes 100g of maleic anhydride was heated to 95°C for 3 hours, cooled to 30°C, added 66ml of 30% potassium hydroxide solution, neutralized to pH 6.0, filtered, washed with water, and dried to obtain 98.2g of maleic hydrazide (mp: 306-307°C, the yield is 96.5%).

technical field

[0001] The invention relates to a preparation method of maleic hydrazide, a selective and temporary plant growth inhibitor. 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 yield and manufacturing cost, sulfuric acid is mostl...

Examples

Embodiment 1

[0022] Preparation of maleic hydrazide

[0023] In a 1000ml four-necked round bottom flask equipped with mechanical stirring, thermometer and condenser, add 220g of water, 44g of concentrated sulfuric acid and 44ml of hydrazine hydrate, 5g of benzoic acid react at 30-40°C for 30 minutes, then add 100g of butene Diacid anhydride, heat up to 95°C for 3 hours, cool down to 30°C, add 76ml of 30% sodium hydroxide solution, neutralize to pH 6.0, filter, wash with water, and dry to obtain 97.0g of maleic hydrazide (mp: 306-307°C, Yield .95.4%).

Embodiment 2

[0025] In a 1000ml four-neck round bottom flask equipped with mechanical stirring, thermometer and condenser tube, add 220g of water, 44g of concentrated sulfuric acid and 44ml of hydrazine hydrate, and add 5.8g of o-toluic acid after reacting at 30-40°C for 30 minutes 100g of maleic anhydride was heated to 95°C for 3 hours, cooled to 30°C, added 66ml of 30% potassium hydroxide solution, neutralized to pH 6.0, filtered, washed with water, and dried to obtain 98.2g of maleic hydrazide (mp: 306-307°C, the yield is 96.5%).

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