| 主权项 |
1. A method of making a methylene malonate monomer said method comprising the steps of:
a) reacting a malonic acid ester or malonic acid ester precursor with a source of formaldehyde, in the presence of a catalyst, alone or in further combination with an acid, a solvent or both an acid and a solvent, wherein a reaction phase polymerization inhibitor is added to the reaction mix prior to, concurrent with, or following the initial reaction of the malonic acid ester or its precursor, as applicable, with the formaldehyde source, said reaction phase stabilizer comprising at least one liquid phase primary anionic polymerization inhibitor, alone or in combination with at least one free radical polymerization inhibitor, and b) subjecting the reaction product of (a) to flash distillation to create a vapor phase containing the methylene malonate monomer and recovering the methylene malonate from the vapor phase wherein (i) the flash distillation is carried out in the presence of a separation phase polymerization inhibitor or (ii) the recovery vessel for the methylidene malonate end product contains a separation phase polymerization inhibitor or both (i) and (ii), said separation phase polymerization inhibitor comprising at least one liquid phase anionic polymerization inhibitor, alone or in combination with a free radical polymerization inhibitor. |
