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ChemicalBook CAS DataBase List N-Vinyl-2-pyrrolidone

N-Vinyl-2-pyrrolidone synthesis

6synthesis methods
Industrially, N-Vinyl-2-pyrrolidone (NVP) is produced by reacting 2-pyrrolidone with acetylene in highpressure autoclaves at 130–170 ℃ and pressures of up to 2.6 MPa. Vinylation proceeds in the liquid phase and is catalyzed by 2-pyrrolidone–potassium. The salt is obtained by adding 1–5% potassium hydroxide or caustic potash solution to fresh pyrrolidone and removing excess water by vacuum distillation (batchwise or continuously). The vinylation reaction takes place in a liquid-phase tube or loop reactor, or in a gas-phase reactor. To avoid the danger of acetylene explosions, nitrogen or propane mixtures of acetylene are used instead of pure acetylene. After the vinylation, the crude product obtained is purified by multistep vacuum distillation. Unreacted 2-pyrrolidone and derivatives can be recycled. Excess acetylene is removed by distillation and can also be recycled to the process. ?Another industrially important synthetic route is based on N-(1-hydroxyethyl)-2-pyrrolidone (HEP). In this process, HEP is dehydrated in the gas phase in a heterogeneously catalyzed reaction at 320–400 ℃ and 10 kPa. The obtained crude NVP is purified by vacuum distillation or crystallization.
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Yield:88-12-0 90%

Reaction Conditions:

with Na/SiO2;ammonia at 350; under 750.075 Torr; for 10 h;Catalytic behavior;Reagent/catalyst;Temperature;

Steps:

8.B B. Preparation of N-vinylpyrrolidone

The alkaline component NH3 with N-hydroxyethylpyrrolidone steam as well as N2 were mixed. Heat to reaction temperature to obtained gaseous starting material mixture. Gaseous starting material mixture specific composition is 0.01NH3+ 0.05NHP + 0.94N2; then, The said starting material mixture, under temperature 350 °C, pressure 0.1 MPa and gas phase space velocity 2000h-1 conditons, goes through fixed bed reactor loaded with step A prepared catalyst. After reacting for 10 hours and reaching stability, collect the N-vinylpyrrolidone discharged from the fixed-bed reactor. With the embodiment 1 the same analysis method, in this embodiment the prepared N-vinyl pyrrolidone the analysis of products, obtained by the analysis result to calculate: the conversion rate of NHP 94.0%, NVP selective 95.7%, NVP yield 90.0%, recombinant sub-impurity selective 1.7%.

References:

2016 Location in patent:Paragraph 0171; 0172; 0173; 0174

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