PURPOSE: To produce the titled substance applicable to a solar system, etc. as an organic heat accumulator, by irradiating a 7-substituted norbornadiene with light.
CONSTITUTION: The objective compound of formula II is obtained by irradiating the compound of formula I (R is OH, acyloxy or alkyloxy) at 0W100°C using a high-pressure mercury lamp, a low-pressure mercury lamp, a xenon lamp, sun light, etc. as the light source. Since the compound of formula I is extremely susceptible to oxygen, the process comprising the degassing at the liquid nitrogen temperature and the heating of the system to normal temperature is repeated several times, and the system is sealed under reduced pressure. The production of polymer can be suppressed by this process. The irradiation of the compound of formula I can be carried out by diluting the compound properly with a light- stable solvent (e.g. n-hexane), and irradiating the solution. The isomerization reaction can be further promoted by the addition of a proper sensitizer (e.g. acetophenone).
HAYAKAWA KIYOSHI
KAWASE KAORU
YAMAKITA HIROMI
TAODA HIROSHI
