Infra-red analysis applied to the exchange reaction between ethylene and deuteroethylene

Abstract

The rapid development in recent years of the technique for investigating molecular spectra, both in the ultra-violet and infra-red regions (Barnes and Bonner 1936), might be expected to lead to applications to chemical problems. The reasons why these methods have not been more generally applied are twofold. In the first place the technique is of comparatively recent development and it is only lately that the general background of known molecular spectra has been obtained without which comparative results would be useless. Secondly, the investigation of molecular spectra, particularly vibration spectra which fall in the infra-red region, is laborious, so that if other methods are available these are, in general, to be preferred. Isotopic shifts of the ultra-violet absorption spectra of molecules also occur, but in most cases the vibrational structure is too complex to be suitable as an indicator. The isotopic shift in the pure vibration spectra of molecules due to deuterium substitution for hydrogen is considerable and adequate resolution can readily be obtained. A certain amount of work in the infra-red region of the spectrum has been done on this, since the information these investigations afford on such problems as assignation of fundamental frequencies, validity of assumed force fields, etc. (Sutherland 1935), is invaluable.