Dehydro-norbornyl ester(s) prepn. - from cyclopentadiene monomer or dimer and vinyl carboxylic ester(s), using polymerisation inhibitors

摘要

The esters are of formula (I): and the carboxylic acid vinyl esters are of formula (II): CH2=CH-O-CO-R (II) (where R=H, CH3, CH2Cl, C2H5 or C6H5). They are reacted in the liq. phase at 200-300 degrees C, esp. 220-280 degrees C, for 1-120 min., pref. 15-80 min., and at 15-60 bars pressure. Pref. there is also present 0.003-3%, w.r.t. the starting materials, of phenothiazine and/or hydroquinone as stabiliser inhibiting polymerisation. In this process, the reaction product is worked up by distillation and the byproducts distilling over a temps. higher than that of (I) are recycled. The process is highly selective, calculated on the vinyl ester, e.g. vinyl acetate, and/or dimeric cyclopentadiene.