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Method for continuously preparing (dimethylamine methylene)malononitrile by using micro-reaction system

A dimethylamine methylene and micro-reaction technology, which is applied in the field of continuous preparation of (dimethylamine methylene) malononitrile using a micro-reaction system, can solve the problems of high process cost, long reaction time, and high price. Achieve good separation effect, shorten reaction time and improve yield

Active Publication Date: 2020-12-04
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Kant et al. (Acta CrystalliographicaSection E, 2013, E69, o433) have described the technology of N,N-dimethylformamide dimethyl acetal and malononitrile reaction preparation compound shown in formula (I), and yield is improved to 75% %, the disadvantage is that N,N-dimethylformamide dimethyl acetal is expensive and the process cost is high
However, the prominent disadvantage of this process is that the reaction time is as long as 15 hours, the yield is low, only 40-74%, and the energy consumption is high.

Method used

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  • Method for continuously preparing (dimethylamine methylene)malononitrile by using micro-reaction system
  • Method for continuously preparing (dimethylamine methylene)malononitrile by using micro-reaction system
  • Method for continuously preparing (dimethylamine methylene)malononitrile by using micro-reaction system

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Embodiment 1

[0049] This embodiment provides a method for continuously preparing (dimethylaminomethylene) malononitrile using a micro-reaction system, the micro-reaction system, such as figure 1 As shown, it includes the first micro-mixer 1, microchannel reactor 2, pH adjustment tank 3, the first annular gap centrifugal extractor 4, and the second annular gap centrifugal extractor 5 connected in sequence, wherein the first annular gap Centrifugal extractor 4 and the second annular gap centrifugal extractor 5 are connected in series to form a centrifugal extraction unit, and the micro-reaction system also includes a constant temperature oil bath 6 and a storage tank 7, and the constant temperature oil bath 6 is used to adjust and control the microchannel The reaction temperature in Reactor 2. The first micro-mixer 1 is a T-shaped micro-mixer. The microchannel reactor 2 is a polytetrafluoroethylene tubular microchannel reactor with an inner diameter of 0.8 mm, and its reaction volume is 4 m...

Embodiment 2

[0055] This embodiment provides a method for continuously preparing (dimethylaminomethylene) malononitrile using a micro-reaction system. The micro-reaction system is the same as the micro-reaction system in Example 1, except that only one ring Gap centrifugal extractor.

[0056] The method comprises the steps of:

[0057] (1) The solution obtained after placing 0.06mol of cyanoacetamide, 0.18mol of N,N-dimethylformamide, and 0.006mol of pyridine in a dry reaction flask and mixed with 25.08g of phosphorus oxychloride They were simultaneously pumped into the first micro-mixer 1 for mixing to obtain mixed reaction materials, wherein, the solution obtained after mixing cyanoacetamide, N,N-dimethylformamide and pyridine (with a density of 1.105g / mL ) is pumped in at a flow rate of 0.232mL / min, and phosphorus oxychloride is pumped in at a flow rate of 0.212mL / min. The molar ratio is 1:3:0.1:2.726;

[0058] (2) The mixed reaction material flowing out from the first micro-mixer 1 ...

Embodiment 3

[0062] This embodiment provides a method for continuously preparing (dimethylaminomethylene) malononitrile using a micro-reaction system, the micro-reaction system is the same as the micro-reaction system of Example 1, and the method is the same as that of Example 1 , the difference is that the first micro-mixer 1 is a Y-type micro-mixer.

[0063] In this example, the reaction substrate cyanoacetamide was completely converted, and the yield of the product (dimethylaminomethylene) malononitrile was 96.1%, and the purity was 98.2% (GC).

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Abstract

The invention discloses a method for continuously preparing (dimethylamine methylene)malononitrile by using a micro-reaction system. The method comprises the steps of respectively and simultaneously pumping a solution obtained by mixing cyanoacetamide, N,N-dimethylformamide and a catalyst and phosphorus oxychloride into a micro-reaction system comprising a first micro-mixer and a micro-channel reactor which are communicated with each other, and carrying out continuous catalytic dehydration condensation reaction; after the pH value of the crude product mixed solution is adjusted, carrying out continuous liquid-liquid extraction separation on the crude product mixed solution in a centrifugal extraction unit composed of a plurality of annular space type centrifugal extractors connected in series by using an organic solvent, collecting an extraction phase to obtain the target product (dimethylamine methylene)malononitrile. Compared with the prior art, the method has the advantages that thereaction can be safely carried out at normal temperature, the reaction time is short, the product yield is greater than 95%, the efficiency of the technological process is high, the energy consumption is low, and the method has a good industrial application prospect.

Description

technical field [0001] The invention specifically relates to a method for continuously preparing (dimethylaminomethylene) malononitrile using a micro-reaction system. Background technique [0002] (Dimethylaminomethylene) malononitrile (I), its chemical structural formula is: [0003] [0004] synthetic vitamin B 1 important intermediates. Singh et al. (Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1984, 23B, 1176-1180) reported N, N-dimethyl-N-(methylsulfanyl methylene ammonium iodide) A method for preparing a compound represented by formula (I) by reacting with malononitrile. The N,N-dimethyl-N-(methylsulfanyl methylene ammonium iodide) used in this method is expensive and difficult to prepare. Ikawa et al. (Tetrahedron Letters, 1969,38,3279-3281) have developed malononitrile and N,N-dimethylformamide and ethyl chloroformate react the technology of compound shown in formula (I), but yield is extremely Low, only 10%. Gate ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C253/30C07C253/34C07C255/30B01J19/00B01D11/04
CPCC07C253/30C07C253/34B01J19/0093B01D11/0496C07C255/30C07C253/20B01J2219/00795C07C255/09B01J2219/00797B01J2219/00867B01J2219/00891B01J2219/00997C07C255/25
Inventor 陈芬儿姜梅芬程荡刘敏杰黄华山
Owner FUDAN UNIV
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