PHOTOCHEMICALLY ACTIVATED CYCLOPROPANE PRODUCED FROM PHOTOLYSIS OF 1-PYRAZOLINE

1-Pyrazoline has been photolyzed in the gas; phase with light of 3130 Å. Cyclopropane, propylene, and ethylene were among the products. The ratio of propylene to cyclopropane depended on the pressure; the ethylene was only slightly dependent. Propylene is formed from at least two sources, only one of which is pressure dependent. The photolysis has been interpreted in terms of a singlet biradical trimethylene which forms “hot” cyclopropane and can then isomerize to propylene or be deactivated to cyclopropane. The “hot” cyclopropane is not monoenergetic but has energy distributed around 75 kcal/mole. © 1969, American Chemical Society. All rights reserved.