PVP and its monomer NVP were synthesized by BASF company J. Walter. Reppe with acetylene as the main raw material. This method is called Reppe method, also known as acetylene method.
Acetylene method: Using acetylene, formaldehyde, hydrogen, etc. as starting materials, monomer NVP was synthesized through five steps, including catalytic aldehyde addition, catalytic hydrogenation, catalytic dehydrogenation, cyclization, amination, and acetylene addition. Then PVP with different molecular weights was obtained by polymerization under certain conditions. Copolymer PVP was obtained by copolymerization of NVP with other monomers, such as vinyl acetate, acrylamide, etc., or cross-linking polymerization was carried out by adding specific cross-linking agents with bifunctional groups, such as N, N-methylene bisacrylamide, etc., to obtain cross-linked PVP. Because the main raw material used in the acetylene method is strict with the operating conditions, the process needs to be carried out under the conditions of high pressure and high temperature. It has high requirements for equipment, long process flow, and large equipment. It is only suitable for large-scale production and is not suitable for building small and medium-sized manufacturers.