反应详情

The preferred embodiment of the improved process of this invention involves the use of the above mentioned process modifications of the prior art process, particularly the use of the polymerization inhibitor phenothiazine, with the additional process improvement of heating the 7-methoxycycloheptatriene in the second step of the process to an elevated temperature, e.g., 180° C. at reduced pressure to give a final product 1-methoxycycloheptatriene of increased mole percent yield and purity. More specifically, it has been found that when 7-methoxycycloheptatriene is heated at 180° C. under reduced pressure, a substantial quantity of the order of 80 mole % of 7-isomer is isomerized to 1-methoxycycloheptatriene with complete consumption of the 7-isomer whereas heating at 150° C. (atmosphere pressure), as in the prior art process, yields the 3-methoxycycloheptatriene as a major component with only approximately 12-13 mole % 1-methoxycycloheptatriene product. Subsequent acid catalyzed rearrangement (step 3 of the synthesis) of the product in the preferred process yields a final product containing approximately 92 mole % of the 1-methoxy isomer and a purity of methoxy isomers of 99 mole % versus a yield of 90 mole % 1-methoxy isomer (96% purity of methoxy isomer) obtained when the improved process of this invention utilizes the atmospheric heating at 150° C. of the prior art process.