This process is a process for production of a vinyl chloride polymer by suspension polymerization or emulsion polymerization of vinyl chloride monomer or a mixture of vinyl chloride monomer with a vinyl monomer copolymerizable with said vinyl chloride monomer in an aqueous medium, characterized in that the polymerization is carried out in a polymerizer, the inner wall surface and portions of the auxiliary equipment thereof which may come into contact with the monomer during polymerization being previously coated with a scaling preventive comprising at least one selected from dyes, pigments and aromatic or heterocyclic compounds having at least 5 conjugated π bonds, while controlling the chloride ion concentration in the reaction mixture to not higher than 100 ppm. According to said process, scaling onto the inner wall surface of a polymerizer, etc. during polymerization can be prevented effectively and surely.
An efficient solvent free multicomponent synthesis of functionalized 4H-chromenes by using reusable, heterogeneous Amberlite IRA-400 Cl resin as catalyst
A simple and efficientAmberlite IRA-400 Cl resin catalyzed multicomponent reaction of 2-hydroxy-1-naphthaldehyde, 1,3-diketone, and nucleophile under solvent free condition to obtain the biological important 4H-chromene derivatives has been outlined. Significant features of this method are the simplicity of the procedure, the ready accessibility, and cost effectiveness of the catalyst, and higher yields