Prepn process of acyldhydrazino adipate with free hydrazine content lower than 10ppm

A technology of adipate dihydrazide and dimethyl adipate, applied in the preparation of hydrazide, organic chemistry, etc., can solve the problems of human and environmental hazards, difficult to remove and clean, and achieve the effect of low pollution

Inactive Publication Date: 2006-08-02
凌青云
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Problems solved by technology

Because hydrazine hydrate must be used in the reaction process, there is free hydrazine in the target object, and it is difficult to remove it. Free hydrazine (also known as hydrazine) is a highly toxic drug, and its existence will definitely cause harm to the h...

Method used

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  • Prepn process of acyldhydrazino adipate with free hydrazine content lower than 10ppm
  • Prepn process of acyldhydrazino adipate with free hydrazine content lower than 10ppm

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specific Embodiment approach

[0014] The present invention uses adipic acid and methanol as raw materials, first obtains dimethyl adipate according to the existing synthesis technology, and then synthesizes it with hydrazine hydrate to obtain the crude product of adipic acid dihydrazide, and the crude product of adipic acid dihydrazide in the Distilled with medium-temperature steam under negative pressure conditions to obtain adipic acid dihydrazide refined product, the main content of which is greater than or equal to 99.0%, the content of free hydrazine is less than or equal to 10ppm, the distillation temperature is controlled at 60 ° C ~ 65 ° C, and the vacuum degree is 0.095 MPa Distillation time 6 hours.

[0015] The specific preparation method is as follows:

[0016] The first step: take 525Kg of adipic acid and 575Kg of methanol, add 15Kg of concentrated sulfuric acid dropwise, reflux for 8 hours to evaporate the alcohol, wash with soda ash until the pH of the solution is neutral to obtain dimethyl ...

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Abstract

The present invention discloses the preparation process of dihydrazide adipate with free hydrazine content lower than 10 ppm. The preparation process includes synthesis of adipic acid and methanol to produce dimethyl adipate, the subsequent synthesis with hydrazine hydrate to obtain crude dihydrazide adipate product, and distilling the crude dihydrazide adipate product at negative pressure condition in medium temperature water vapor to obtain refined dihydrazide adipate product with free hydrazine content lower than 10 ppm. The refined dihydrazide adipate product has high performance, low pollution and environment friendship and is used in producing environment friendly water paint.

Description

Technical field: [0001] The invention relates to a method for reducing the content of free hydrazine in adipic dihydrazide. Background technique: [0002] Adipate dihydrazide (also known as ADH), the chemical formula is C 6 h 14 N 4 o 2 , the molecular weight is 173.24, and the appearance is white powdery crystal. Adipic acid dihydrazide is an important cross-linking agent for environmentally friendly water-based coatings. With the wide application of water-based coatings, the room-temperature cross-linking of water-based coatings has also attracted more attention from experts. At present, the existing production technology of ADH is to use adipic acid and methanol as starting materials to first synthesize dimethyl adipate, and then synthesize it with hydrazine hydrate to obtain adipate dihydrazide. Because hydrazine hydrate must be used in the reaction process, there is free hydrazine in the target object, and it is difficult to remove it. Free hydrazine (also known as...

Claims

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Application Information

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IPC IPC(8): C07C243/34C07C241/04
Inventor 凌青云
Owner 凌青云
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