NVP can be widely used in adhesives, coatings, textiles, food, pharmaceuticals and other industrial fields. Most of its copolymers or homopolymers have good film strength, dyeing compatibility, rigidity and viscosity. About 80 years ago, German J. Walter. Reppe used acetylene as the starting material to synthesize NVP through multi-step reactions (i.e., acetylene method or Reppe method). 20 years later, GAF Company in the United States and BASF Company in Germany successively adopted the Reppe method to achieve industrial production of NVP.
Mix, dissolve 112.8g of hexahydrated nitrate in 300ml of water, then add it to the prepared diatomaceous earth-ammonium dihydrogen phosphate mixture system and mix thoroughly, heat the mixture in a water bath and evaporate to dryness, dry the obtained solid at 120℃ for 3h, and then at 400℃ ℃ calcined in air for 3h to obtain la(H,PO)3/diatomite catalyst. 2.MRSi,X,O,catalyst 11 This is a type of composite catalyst composed of alkali metal or alkaline earth metal, silicon, oxygen and other elements. In the formula, M represents alkali metal or alkaline earth metal, X is one of boron, aluminum or phosphorus, a, b, c, d represent the number of atoms of the four elements respectively, when a=1, b value is between 1~500, c=0~1, d value depends on the value of a, b, c and the connection between the four elements.
The catalyst used in this reaction is still an alkali metal or an alkali metal hydroxide. The typical experimental steps are as follows: Take 0.4g potassium hydroxide and dissolve it in 170g (2mol) 2-pyrrolidone, heat and stir, and continuously remove the generated water by vacuum distillation to obtain a mixture A, which is cooled for use. Add 172g (2mol) of vinyl acetate to a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel, and then drop the A mixture under stirring, and the dripping is completed within 30 minutes. The temperature of the reactant system is kept below 10°C during the cooling and dripping process. After the addition is completed, the temperature is raised to 80°C, and vacuum distillation is performed (pressure 6.6×10~3MPa, then the temperature is gradually raised and the internal pressure of the reactor is reduced until the internal pressure reaches 1.3×10+MPa at a temperature of 100°C.
