Production of N-vinyl-pryyolidone

Abstract

Production of N-vinyl pyrrolidone is carried out by using alkali metal or alkali salt, rare earth nitrate and carbon white as raw materials, using poly-oxide MaSibLacRed(a, c, d=0í½1, b=1í½100) as catalyst, diluting NHP steam from nitrogen, catalytic and dehydration reacting for intermediate product NHP at normal pressure, and obtaining N-vinyl pyrrolidone. Its advantages include simple apparatus, convenient operation and easy reaction process control.

Description

technical field [0001] The invention relates to a preparation method of N-vinylpyrrolidone. Background technique [0002] Polyvinylpyrrolidone (PVP) has excellent solubility, physiological compatibility, chemical stability, film forming, solubilization, adhesive ability, moisture retention and other excellent properties. and other fields, as well as new materials such as separation membranes and gels, have a wide range of applications. [0003] The technical key to the preparation and application of PVP is the preparation of its main monomer NVP. The earliest NVP preparation method was the acetylene method first developed by the German BASF company in the 1930s. This method experienced aldehyde addition, catalytic hydrogenation, and catalytic desorption of acetylene. Hydrogen ring formation to obtain γ-butyrolactone, ammonolysis of γ-butyrolactone to obtain pyrrolidone, addition of pyrrolidone to acetylene and other five-step reactions to obtain monomer NVP. The acetylene ...

AI Technical Summary

Problems solved by technology

Both thionyl chloride and hydrochloric acid can be used as halogenation agents to obtain higher NVP yields, but there are two fatal shortcomings in the halogenation method: one is that by-product acids or salts will be generated during the reaction, resulting in a reduction in the quality of NVP products The second is that the amount of halogenating agent used in the reaction is relatively large (generally 0.8 to 1.2 times that of NHP), and a large number of by-products are generated, which increases the difficulty of post-processing of the product and causes environmental pollution.

[0007] The NHP catalyzed dehydration reaction of the direct dehydration method of γ-butyrolactone generally requires a vacuum degree above 0.09MPa. Such a high vacuum degree, on the one hand, requires higher conditions control in the production process and correspondingly higher requirements for equipment. This is especially true when continuous production is to be realized; on the other hand, in the production process, the equipment utilization rate is low and the production efficiency is low, thereby increasing the production cost

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