A. Misono, T. Osa, Yoshitomo Sanami
Oct 1, 1968
Citations
0
Influential Citations
5
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
The gas-phase dehydration of tetrahydropyran-2-methanol (TPM), prepared by the hydrogenation of the acrolein thermal dimer (3,4-dihyro-2H-pyran-2-carboxaldehyde (AD)), was investigated over various catalysts under atmospheric pressure. In this reaction, some of the pyran ring was found to be rearranged rapidly to a seven- or five-membered ring. For example, the highly-purified and crystalline η-alumina without any carrier produced cyclopentanecarboxaldehyde (GPA) as the main product in the yield of 71% at 330°C. Over the commercial alumina catalyst, considerable amounts of 2,3,4,5-tetrahydrooxepine (THO) and oxepane (OXP) were produced as by-products, though CPA was the main product; in some cases, as much THO and OXP were produced as CPA. On the other hand, the use of a dehydrogenation catalyst resulted in THO as the main product and CPA as a by-product; in the case of the use of copper-chromium oxide supported on Kieselguhr, with hydrogen as a carrier gas at 430°C, the yields of THO and CPA were 44.8% a...