A new method of catalytic synthesis of methylhydrazine under normal pressure

A synthetic method and technology of methylhydrazine, applied in the preparation of hydrazine, organic chemistry, etc., can solve the problems of high toxicity of dimethyl sulfate, increase of sodium salt treatment cost, difficulty in industrial production, etc., to achieve convenient continuous production, improve Product selectivity, the effect of easy industrial production

Inactive Publication Date: 2017-03-29
UNIV OF JINAN
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Problems solved by technology

However, dimethyl sulfate is highly toxic and has potential safety hazards. At the same time, a large amount of difficult-to-handle sodium salt will remain after the dissociation, which undoubtedly increases the cost of sodium salt treatment and brings very troublesome environmental protection problems. Therefore, this process is difficult to industrialize. Production

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  • A new method of catalytic synthesis of methylhydrazine under normal pressure
  • A new method of catalytic synthesis of methylhydrazine under normal pressure
  • A new method of catalytic synthesis of methylhydrazine under normal pressure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Slowly add 192.1 g (2.0 mol) of 38% concentrated hydrochloric acid dropwise into 125 g (2.0 mol) of 80% hydrazine hydrate. Under the condition of stirring, control the temperature at 20~30°C and keep it warm for 2 hours. After the reaction is complete, measure the pH=6, distill off the water under reduced pressure, mix the obtained hydrazine salt with 138 g (3 mol) of ethanol, and add coarse porous microspherical silica gel 16.0 g. Raise the reaction temperature to 73° C. and condense to reflux. Chloromethane was slowly introduced into the mixed solution at a rate of 0.56 mL / min to react for 2.3 h. The mixed solution after the reaction is distilled to separate ethanol and a small amount of water, and the ethanol can be recycled. The remaining raffinate was added to 136.0 g of hydrazine hydrate with a mass fraction of 80% for freeing. Finally, the dissociated solution was heated and rectified, and the fraction at 102-110°C was collected to obtain 98.0 g. The content of...

Embodiment 2

[0043] Add 96.05 g (1.0 mol) of 38% concentrated hydrochloric acid dropwise to 62.5 g (1.0 mol) of 80% hydrazine hydrate. Under the condition of stirring, control the temperature at 20~30°C and keep it warm for 1.5 hours. After the reaction is complete, measure the pH=6, distill off the water under reduced pressure, mix the obtained hydrazine salt with 92 g (2.0 mol) of ethanol and add microporous microspheres Type 8.3g of silica gel, raise the reaction temperature to 64°C and condense to reflux, slowly inject methyl chloride into the mixed solution at a rate of 0.22mL / min to react for 2 h. The mixed solution after the reaction is distilled to separate ethanol and water, and the ethanol can be recycled. The remaining raffinate was added to 50 g of hydrazine hydrate with a mass fraction of 80%. Finally, the dissociated solution was heated and rectified, and the fraction at 102-108°C was collected to obtain 63.3 g fraction, with a gas phase detection content of 38.12%. The rem...

Embodiment 3

[0045] Add 134.6 g (1.4 mol) of 38% concentrated hydrochloric acid dropwise to 127.5 g (1.4 mol) of 80% hydrazine hydrate. Under the condition of stirring, control the temperature at 20~30°C and keep it warm for 1.0 h. After the reaction is complete, measure the pH=6, distill off the water under reduced pressure, mix the obtained hydrazine salt with 96.6 g (2.1 mol) of ethanol and add coarse-pored microspheres Type 9.3 g of silica gel, raise the reaction temperature to 51°C and condense to reflux, slowly inject methyl chloride into the mixed solution at a rate of 0.294 mL / min, and react for 1.0 h. The mixed solution after the reaction is distilled to separate ethanol and water, and the ethanol can be recycled. The remaining raffinate was added to 130 g of hydrazine hydrate with a mass fraction of 80%. Finally, the dissociated solution was heated and rectified, and the fraction at 102-108°C was collected to obtain 42.9 g of fraction, whose gas phase detection content was 32.02...

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Abstract

The invention discloses a new method for catalytically synthesizing methylhydrazine under normal pressure. It is characterized in that: react hydrazine hydrate and methylene chloride with hydrochloric acid as protective agent, silica gel as catalyst, ethanol as solvent, and react under normal pressure at 70-74°C to generate methylhydrazine hydrochloride. Using the method of freeing hydrazine, after freeing methylhydrazine through hydrazine hydrate, an aqueous solution of methylhydrazine is obtained through a rectification process. The free by-product-hydrazine hydrochloride can be recycled. The invention has the following advantages: relatively low equipment cost and raw material price, high reaction yield and good selectivity, no three wastes, strong environmental protection, internal circulation of the process, convenient continuous production, and reaction at normal pressure It is easy to operate and safe in production.

Description

technical field [0001] The invention relates to a new method for catalytically synthesizing methylhydrazine under normal pressure. Background technique [0002] Methylhydrazine is also known as monomethylhydrazine, molecular formula: CH 6 N 2 , Molecular weight: 46.07, widely used in pesticides, medicines, dyes, etc., because of its low freezing point, good thermal stability and stable combustion process, it is considered the most promising rocket propellant fuel among hydrazine fuels. [0003] There are many reports on the synthetic method of methylhydrazine, currently according to the existing literature synthetic method mainly contains the following: [0004] Chloramine method [0005] Patent US 4192819 first disclosed the process of synthesizing methylhydrazine by chloramine method, which mainly uses sodium hypochlorite and ammonia to react to produce chloramine, and then reacts chloramine and monomethylamine to generate methylhydrazine. [0006] [0007] This tec...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C241/02C07C243/14
Inventor 郑庚修刘庆东刘悦马志佳杨柳付凯
Owner UNIV OF JINAN
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