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Circulating process method for preparing N-methylalkyl secondary amine

A technology of methyl alkyl secondary amines and process methods, which is applied in the fields of pesticide synthesis intermediates, chemical research reagents and medicines, and the preparation of CH3NHnCH3, which can solve the problems of long steps, poisonous dimethyl sulfate, and expensive methyl iodide, etc., and achieve low cost effect

Inactive Publication Date: 2013-04-03
张秋平
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has long steps, the reagent methyl iodide is expensive, and dimethyl sulfate is poisonous, so it is still not suitable for industrial production.

Method used

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  • Circulating process method for preparing N-methylalkyl secondary amine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Preparation of N-methylbenzamide

[0029] Install a mechanical stirrer, a thermometer, a reflux condenser, and a constant pressure dropping funnel on a 5L four-necked bottle. Add 1061g (5mol) benzyl benzoate and 620g (8mol) 40% methylamine aqueous solution in the four-neck flask. Stir and react at room temperature (20-30°C) for 6 hours, gradually heat up to 110°C, absorb the methylamine evaporated during this period with a conical flask containing 155g of water in an ice-water bath, and stop heating when 20mL of water evaporates to obtain A mixture of N-methylbenzamide, benzyl alcohol and water is obtained.

[0030] The same operation was repeated several times for the following preparations.

Embodiment 2

[0032] Preparation of N-methylethylamine

[0033] 200 g (5 mol) of solid NaOH was added to the mixture obtained in Example 1, and then heated to 35° C., and 545 g (5 mol) of bromoethane was added dropwise with stirring. After the dropwise addition, reflux was continued for 4 hours under stirring at 35°C until the ethyl bromide disappeared completely. At this time, a large amount of sodium bromide solid precipitated out.

[0034] 1300 mL of water was added to the reaction mixture, and the sodium bromide brine layer was separated. The organic layer was a mixture of N-methyl-N-ethylbenzamide and benzyl alcohol. This mixture was transferred to a 2L three-neck flask equipped with a stirring, thermometer and Vickers fractionation column with a length of 60cm, stirred and gradually raised to 150°C for complete dehydration. Cool slightly to 120°C, add 10g of sodium benzyl alcohol, continue to heat up, and keep the temperature at the top of the fractionation column between 35 and 40...

Embodiment 3

[0037] Preparation of N-methylpropylamine

[0038] Add 200 g (5 mol) of solid NaOH to the mixture obtained in Example 1, then heat to 50° C., and add 615 g (5 mol) of 1-bromopropane dropwise with stirring. After the dropwise addition, the reflux was continued for 4 hours under stirring at 50°C until the 1-bromopropane disappeared completely. At this time, a large amount of sodium bromide solid precipitated out.

[0039]1300 mL of water was added to the reaction mixture, and the sodium bromide brine layer was separated. The organic layer was a mixture of N-methyl-N-propylbenzamide and benzyl alcohol. This mixture was transferred to a 2L three-neck flask equipped with a stirring, thermometer and Vickers fractionation column with a length of 60cm, stirred and gradually raised to 150°C for complete dehydration. Cool slightly to 120°C, add 10g of sodium benzyl alcohol, continue to heat up, and keep the temperature at the top of the fractionation column between 60 and 65°C. When...

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Abstract

The invention belongs to the technical field of fine chemicals and synthesis methods thereof and discloses a circulating process method for preparing high-purity N-methylalkyl secondary amine. The method for preparing the N-methylalkyl secondary amine adopts a technical scheme which comprises that: firstly, benzyl benzoate serving as a circulating medium undergoes an ammonolysis reaction with excessive methylamine aqueous solution which together with a halohydrocarbon serves as a raw material to form N-methylbenzamide; secondly, the N-methylbenzamide forms benzamide negative ions under the action of sodium hydroxide in the same amount, and the negative ions undergoes nucleophilic substitution with alkyl halide in the small amount or alkyl dihalide in half amount to form N-methyl-N-alkyl benzamide; and finally, the N-methyl-N-alkyl benzamide and benzyl alcohol undergo reverse alcoholysis at a high temperature and in the presence of a sodium benzyl alcoholate catalyst to form benzyl benzoate again, and the substituted low-boiling point N-methylalkyl secondary amine is distilled off from the tower top of a rectifying tower. The method has the characteristics of environmental friendliness and low cost, and is suitable for batch production of high-purity N-methylalkyl secondary amine.

Description

technical field [0001] The invention relates to a recycling process for preparing N-methylalkyl secondary amines, which belongs to the technical field of fine chemicals and their synthesis methods, and specifically relates to the preparation of CH 3 NH(CH 2 ) n CH 3 (n=1, 2, 3, 4, 5), or CH 3 NH(CH 2 ) m NHCH 3 (m=2, 3) method, this type of N-methyl secondary amine is widely used in chemical research reagents and medicine, pesticide synthesis intermediates. Background technique [0002] N-methylalkyl secondary amines are widely used in chemical research and pharmaceutical intermediates. For example: N-methylethylamine is a key intermediate for the preparation of the drug rivastigmine for the treatment of Alzheimer's disease; N-methylpentylamine is an important intermediate for the bisphosphonate drug Ebenphosphate Sodium. [0003] At present, the preparation methods of these compounds mainly include the direct amination of halogenated hydrocarbons, the substitution o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C209/62C07C211/08C07C211/10C07C211/11
Inventor 张秋丽何磊魏薇陈爱允
Owner 张秋平