Process for continuously preparing N, N-dimethyl-1, 3-propane diamine by using micro-mixing and fixed bed reactors

A technology of fixed bed reactor and dimethylaminopropionitrile, which is applied in the field of preparing N, can solve the problems of low production efficiency and long process reaction time, and achieve the effects of low cost, improved hydrogenation efficiency, and improved mass and heat transfer

Pending Publication Date: 2021-08-03
DALIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The synthesis route of this process is simple, the yield is high, and it is easy to realize industrial p...

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  • Process for continuously preparing N, N-dimethyl-1, 3-propane diamine by using micro-mixing and fixed bed reactors

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Experimental program
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Effect test

Embodiment 1

[0024] (1) Firstly, the catalyst Raney-Ni is loaded into the reactor 10 . (2) Open the nitrogen cylinder 19, purge the whole system, discharge the air, set the pressure on the micro-mixing reactor 6 through the nitrogen pressure reducing valve 16: 2MPa, and set the temperature by the temperature controller 8: 35°C. The pressure of the fixed bed reactor 10 is set by the hydrogen cylinder 17 through the pressure reducing valve 16 to the system to set the hydrogen pressure: 3MPa, and the hydrogen flow rate is controlled by the mass flow controller 15, and the temperature is set by the temperature controller 8 to 70°C. (3) Use two double-plunger micropumps 4 to transport dimethylamine (100%) and acrylonitrile (99%) to the micro-mixing reactor 6 with a molar ratio of 1.1:1 for reaction, and the residence time is 1 min Under certain conditions, continuous reaction makes the reaction liquid that contains dimethylaminopropionitrile, and the mass fraction of dimethylaminopropionitrile ...

Embodiment 2

[0026] Using the production method of Example 1, the difference is that the concentration of 40% dimethylamine aqueous solution is used, the concentration of acrylonitrile is 99%, the molar ratio of dimethylamine to acrylonitrile is 1.5:1, the reaction temperature is 25°C, and the reaction pressure is The residence time of 1MPa is 0.5min, the catalyst for hydrogenation is: ethanol solution of 4% NaOH, the content of dimethylaminopropionitrile in the hydrogenation raw material is 35%, the content of NaOH is 0.5%, and the molar ratio of hydrogen to dimethylaminopropionitrile is 5:1 , the reaction temperature is 65°C, the reaction pressure is 4MPa, the residence time is 40min, the hydrogenation catalyst is: Raney Ni, the conversion rate of acrylonitrile is 99.8%, and the yield of N,N-dimethyl-1,3-propanediamine is 98.6% %.

Embodiment 3

[0028] Using the production method of Example 1, the difference is that the concentration of dimethylamine in methanol is 30%, the concentration of acrylonitrile is 99%, the molar ratio of dimethylamine to acrylonitrile is 1.2:1, and the reaction temperature is 30°C. The pressure is 2 MPa and the residence time is 2 minutes. The hydrogenation catalyst is: methanol solution of 10% NaOH, the content of dimethylaminopropionitrile in the hydrogenation raw material is 28%, the content of NaOH is 2.5%, and the molar ratio of hydrogen to dimethylaminopropionitrile is 20:1 , the reaction temperature is 55°C, the reaction pressure is 3MPa, the residence time is 60min, the hydrogenation catalyst is: Raney Ni, the conversion rate of acrylonitrile is 99.8%, and the yield of N,N-dimethyl-1,3-propanediamine is 98.1 %.

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Abstract

The invention discloses a process for continuously preparing N, N-dimethyl-1, 3-propane diamine by using micro-mixing and fixed bed reactors, and belongs to the technical field of organic chemical industry. A micro-mixing reactor and a fixed bed reactor are connected in series, and dimethylamine and acrylonitrile are used as raw materials to continuously prepare N, N-dimethyl-1, 3-propane diamine. By adopting the micro-mixing reactor, mass transfer and heat transfer of the reaction of dimethylamine and acrylonitrile are greatly improved, the reaction time of the first step is shortened to 0.3-4 min, and the probability of deterioration of the intermediate dimethylaminopropionitrile is reduced. Through the micro-mixing reactor, the gas-liquid raw materials in the second step are mixed more uniformly, the hydrogenation efficiency is improved, the yield of the prepared N, N-dimethyl-1, 3-propane diamine is greater than or equal to 98%, and the acrylonitrile conversion rate is greater than or equal to 99%. The process method can easily realize continuous production, low in cost, green, environment-friendly and suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry, and relates to a process for preparing N,N-dimethyl-1,3-propanediamine using micro-mixing and fixed-bed reactors Background technique [0002] N,N-Dimethyl-1,3-propanediamine belongs to lower aliphatic diamine and is an important organic chemical intermediate, widely used in medicine, feed, food and other fields. For example, N,N-dimethyl-1,3-propanediamine can be used in the synthesis of surfactants, preservatives, lubricating oil additives, etc. [0003] At present, the main production process of N,N-dimethyl-1,3-propanediamine is to use acrylonitrile and dimethylamine as raw materials, firstly prepare the intermediate dimethylaminopropionitrile, and then obtain N,N -Dimethyl-1,3-propanediamine. [0004] Patent CN103333073A uses dimethylamine and acrylonitrile as raw materials to prepare N,N-dimethyl-1,3-propanediamine through catalytic hydrogenation. This method is prepared...

Claims

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Application Information

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IPC IPC(8): C07C211/09C07C209/48
CPCC07C209/48C07C253/30C07C211/09C07C255/24
Inventor 孟庆伟谭威卫源安都健
Owner DALIAN UNIV OF TECH
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