Reaction of bacterial poly-3-hydroxybutyrate with thionyl chloride in the presence of zinc chloride, and preparation of chlorine-containing oligomers
Poly-3-hydroxybutyrate (PHB) was subjected to degradation by thionyl chloride in the presence of zinc chloride in chloroform solution. 0.025 mol (2.15 g) of PHB calculated by a PHB monomer fragment (86 g/mol) was dissolved by heating at 50°C in 100 ml of chloroform with stirring on a magnetic stirrer. After complete dissolution, at a temperature of 50°C and strong stirring (750 rpm), 0.0025 mol (340 mg) of finely crystalline zinc chloride was added, followed by 0.1 mol (7.26 ml) of thionyl chloride. Continued heating and stirring under reflux. Samples were periodically taken by precipitating the polymer with hexane at a polymer solution to hexane volume ratio of 2:5, followed by washing and purification on a Schott filter. The experiment was carried out for 96 hours. Molecular weight for all samples was measured three times.