The synthetic method of n-vinylpyrrolidone

A technology of vinylpyrrolidone and pyrrolidone, which is applied in the field of synthesis of N-vinylpyrrolidone, can solve the problems of operation controllability, poor product uniformity, and long reaction time, and achieve rapid delivery, precise control, and high product consistency , hot spot or overtemperature reduction effect

Active Publication Date: 2021-08-31
TSINGHUA UNIV
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Problems solved by technology

On the one hand, there are still some problems to be solved when using autoclave production: first, the reaction is a gas-liquid two-phase reaction, and the reaction rate is controlled by gas-liquid mass transfer. The reaction process depends largely on the stirring speed, and the low reaction rate directly leads to the reaction The time is very long (3 ~ 5h); secondly, the process is an intermittent operation, and the operation controllability and product uniformity are relatively poor

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  • The synthetic method of n-vinylpyrrolidone
  • The synthetic method of n-vinylpyrrolidone
  • The synthetic method of n-vinylpyrrolidone

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preparation example Construction

[0036] According to one aspect of the present invention, there is provided a method for synthesizing N-vinylpyrrolidone, comprising: passing acetylene and catalyst-containing 2-pyrrolidone liquid into a microchannel reactor for reaction to obtain N-vinylpyrrolidone;

[0037] Wherein: the content of catalyst in the 2-pyrrolidone liquid containing catalyst is 2.2-10.5wt%; The volume flow ratio of acetylene and the 2-pyrrolidone liquid containing catalyst is (32-270): 1; The inner diameter is less than 3mm.

[0038] In the above synthesis method, a microchannel reactor with a specific single-channel inner diameter is used for the reaction between the reaction raw materials. The inner diameter is very small and has a flame arrester effect, which can greatly reduce the risk of decomposition and explosion of acetylene, and the microchannel reactor also has With high specific surface area and short material diffusion distance, the mass and heat in it can be quickly transferred and pr...

Embodiment 1

[0073] A kind of synthetic method of N-vinylpyrrolidone, comprising:

[0074] Put 0.6kg of potassium hydroxide and 20kg of 2-pyrrolidone in the reaction device for vacuum distillation, keep the pressure at 20mbar, the temperature at 120°C, and finish the reaction after 2h. At this time, the water content in the catalyst-containing 2-pyrrolidone liquid is lower than 500ppm ;

[0075] use figure 1 The process shown in the synthesis of NVP, the total gas flow is 1.8Nm 3 / h, wherein the flow ratio of acetylene and nitrogen is 1:1, nitrogen and acetylene are first dried through drying column 1, the flow rate of the above-mentioned 2-pyrrolidone liquid containing catalyst is 6L / h, and the 2-pyrrolidone liquid containing catalyst is stored in the buffer In the tank 2, the gas and liquid enter the micro-mixer 3 at the set flow rate to achieve mixing at room temperature, then enter the fast heater 4, preheat to 120-135°C, and then enter the tank with a constant temperature of 160°C a...

Embodiment 2

[0078]A kind of synthetic method of N-vinylpyrrolidone, wherein catalyst preparation and technological process are identical with embodiment 1. The reaction temperature is 180°C, and the total gas flow rate is 1.2Nm 3 / h, the above-mentioned catalyzer-containing 2-pyrrolidone liquid flow rate is 12L / h, the inner diameter of a single channel of the microchannel reactor is changed to 0.5mm, and the 316L stainless steel capillary of tube length 40m, other reaction conditions remain unchanged.

[0079] The single-pass conversion rate of 2-pyrrolidone under this operating condition is 7.5%, the total conversion rate of 2-pyrrolidone after 8 cycles is 57.3%, the total reaction time of 8 cycles is 8min, the NVP yield is 57%, and the product NVP The selectivity is 99.5%.

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Abstract

The invention relates to the field of synthesis of fine chemicals, in particular, it provides a synthesis method of N-vinylpyrrolidone. The synthesis method comprises: passing acetylene and catalyst-containing 2-pyrrolidone liquid into a microchannel reactor for reaction to obtain N-vinylpyrrolidone; wherein: the content of catalyst in the catalyst-containing 2-pyrrolidone liquid is 2.2-10.5wt %; The volume flow ratio of acetylene and the 2-pyrrolidone liquid containing the catalyst is (32-270): 1; the inner diameter of the single channel in the microchannel reactor is less than 3mm. The method adopts a liquid phase circulation method to achieve a high conversion rate of the liquid raw material 2-pyrrolidone, and adopts a new reactor microchannel reactor to achieve a high selectivity for the product NVP, and can ensure the intrinsic safety of acetylene, and enhance mass and heat transfer. Realize continuous production, strictly guarantee operation controllability and product consistency.

Description

technical field [0001] The invention relates to the field of synthesis of fine chemicals, in particular to a synthesis method of N-vinylpyrrolidone. Background technique [0002] N-vinylpyrrolidone (NVP for short) is mainly used in the production of polyvinylpyrrolidone (PVP for short). PVP is a non-ionic water-soluble polymer fine chemical. Sex, physiological inertness, bonding ability and protective glue function, and can also be combined with many inorganic, organic and polymer compounds to form a variety of new fine chemicals with unique functions that are incomparable to other compounds. Due to these characteristics, PVP is widely used in industries such as medicine and hygiene, daily chemicals, pigment coatings, office stationery, beverages and food. [0003] The synthesis of monomeric NVP is a key part of the PVP industry chain, and the acetylene method (also known as the Reppe method) is the main process for industrial production of NVP. The acetylene method refers...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D207/267B01J19/00
CPCB01J19/0093C07D207/267
Inventor 程易阎丽芳付哲
Owner TSINGHUA UNIV
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