US Patent 7112650 Method for the production of thermoplastic poly(3-hydroxyalkanoates)

A process for preparing thermoplastic poly(3-hydroxyalkanoates) with a molar mass greater than 6 000 g/mol and a melting point in the range from 70 to 170° C., by reacting an oxirane compound with carbon monoxide in the presence of a transition metal catalyst which has rhodium(0), nickel(0), iron(0), cobalt(0) or palladium(0) as central metal and has been chelated with neutral Lewis bases, and also in the presence of diisocyanates, ortho esters, acetals, anhydrides, P2O5, MgO, MgCl2, MgSO4, zeolites, or a mixture of these, at a pressure in the range from 1 to 250 bar and at from room temperature to 150° C.