METHOD FOR PRODUCING ALPHA-METHYLENE LACTONES

The process consists of a two-step synthesis of α-methylene-γ-butyrolactones from the parent γ-butyrolactones in a single vessel by a process wherein an alkoxide base, a formate ester, and a lactone are reacted using a solvent mixture comprising an aromatic hydrocarbon, and optionally, secondary and/or tertiary alcohols in the first step. By-products that lower overall yield and are difficult to separate from the desired product are eliminated or substantially reduced using a neutralizing agent to convert residual alkoxide to a weak base and/or distillation. In the second stage, a formaldehyde source is introduced to form the final a-methylene lactone. The α-methylene-γ-butyrolactones are useful as monomers for preparing highTg homopolymers or copolymers by various methods for applications with the desirable characteristics of low volatility, increased polymer rigidity, improved optical, and/or thermal stability properties.