Preparation technology of methylhydrazine

A preparation process, a technology of methyl hydrazine, applied in the preparation of hydrazine, organic chemistry, etc., can solve the problems of loss, yield only, catalyst pressure relief, etc., achieve good conversion rate and selectivity, convenient and thorough application, and conducive to free effect of operation

Active Publication Date: 2019-03-22
河北合佳医药科技集团股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] This method uses cheap methanol as a methylation reagent, and the selectivity is better when the conversion rate is lower than 30%, but with hydrazine dihydrochloride (hydrochloric acid) or monochloromethane as a catalyst, excessive alkylation products will still be produced (Unsymmetrical dimethylhydrazine, p-dimethylhydrazine, trimethylhydrazine, etc.), and there are problems such as high pressure in the reaction process, high requirements for corrosion resistance of equipment, and catalysts are usually released at the end of the reaction and completely lost in the distillation process.
CN102516117A has adopted a similar synthetic route, still does not avoid the generation of excessive alkylation products, and the yield only reaches about 65%; CN106543026 has reported a kind of hydrazine hydrate and methanol in sodium bisulfite and sodium p-toluenesulfonate There is a method for preparing methylhydrazine in the next step, but after the applicant's experiment, no reaction was found to proceed

Method used

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  • Preparation technology of methylhydrazine
  • Preparation technology of methylhydrazine

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Experimental program
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Effect test

Embodiment 1

[0026] In the methylation reaction kettle, add 275g (4mol) of hydrazine hydrochloride, 650mL methanol (16mol), 26g (0.2mol) of hydrazine sulfate, then add 70ml of water, seal the reaction kettle, control the system temperature at 90°C to 100°C, and stir React for 3 hours, the pressure of the reaction process system is 0.4-0.5MPa, the reaction is completed, the system is lowered to room temperature and stirred for 1 hour, and filtered to obtain 185g of solid dry product (containing 25g of hydrazine sulfate and 125g of hydrazine hydrochloride). After the filtrate is distilled to recover methanol, add hydration Hydrazine was free, and the fraction was rectified to obtain 210 g of 40% methylhydrazine solution.

Embodiment 2

[0028] In the methylation reactor, add 150 g of the recovered hydrazine sulfate and hydrazine hydrochloride mixture (containing 25 g of hydrazine sulfate, 125 g of hydrazine hydrochloride), 150 g of hydrazine hydrochloride, 500 mL of methanol, then add 80 ml of water, close the reactor, and control the temperature of the system at 50 ℃~60℃, stirred and reacted for 2h, the system pressure was 0.3~0.5MPa during the reaction process, the reaction was completed, the system was lowered to room temperature and stirred for 1h, filtered to obtain 210g of solid wet product (including 25g of hydrazine sulfate and 152g of hydrazine hydrochloride), and the filtrate was distilled After methanol was recovered, hydrazine hydrate was added for freeing, and the fraction was rectified to obtain 177 g of 40% methylhydrazine solution.

Embodiment 3

[0030] In the methylation reaction kettle, add 80% hydrazine hydrate 74g (1.2mol), 36% concentrated hydrochloric acid 120g (1.2mol), after stirring evenly, add the recovered hydrazine sulfate and hydrazine monohydrochloride mixture 150g (containing hydrazine sulfate 25g , hydrazine hydrochloride 125g, 1.8mol), 600mL methanol, airtight reactor, control the system temperature 75 ℃ ~ 85 ℃, stirring reaction 4h, the reaction process system pressure at 0.3 ~ 0.4MPa, the reaction is over, the system is lowered to room temperature and stirred for 1h, filtered , to obtain solid wet product 168g (containing hydrazine sulfate 24g, hydrazine hydrochloride 123g), after the filtrate recovered methanol through distillation, added hydrazine hydrate to free, and the fraction was rectified to obtain 120g of 40% methylhydrazine solution.

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Abstract

The invention discloses a preparation technology of methylhydrazine, and belongs to the technical field of organic synthesis. The preparation technology comprises the following steps: (1) adding hydrazine monohydrochloride and methanol into a reaction kettle, then adding water and a catalyst, and then rising the temperature for carrying out methylation, thus obtaining methylhydrazine hydrochloride; (2) directly cooling feed liquid after reaction, separating a solid catalyst from unreacted hydrazine hydrochloride, and carrying out dealcoholizing, dissociating, rectifying and the like on filtrate, thus obtaining the methylhydrazine. The preparation technology disclosed by the invention has the advantages that the reaction selectivity is good, the reaction pressure is low, the catalyst can becompletely and mechanically used, and safety, cleanliness, environment protection and the like are realized.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation process of methylhydrazine. Background technique [0002] Methylhydrazine is an important energy material, and it is also widely used in pesticides, medicine, water treatment and other fields, and it is mostly sold as a 40% aqueous solution. At present, there are many reports on the synthetic method of methylhydrazine, such as hydrazine hydrate benzaldehyde condensation method, dimethyl phosphite or dimethyl carbonate hydrazine hydrate method, -hydrazinoethanol decomposition method, dimethyl sulfate hydrazine hydrate method and other methods, However, industrial production has not been realized because of the high cost of methylating reagents or the reasons of safety and environmental protection. The two methods commonly used in industry are the Raschig method and the hydrazine hydrochloride methanol method. [0003] The Raschig method is also called the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C241/02C07C243/14
CPCC07C241/02C07C243/14
Inventor 刘振强刘新元韩布兴梁丙辰王宇栋白伟东孟龙超姜鹏鹏孙美婷
Owner 河北合佳医药科技集团股份有限公司
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