AbstractsChemistry

The conjugated diolefinic hydrocarbons have formed the subject of many investigations during the past forty years. This has been on account of the increasing commercial importance of a few such compounds in the manufacture of synthetic rubbers and similar polymers, and the utilization of by-products of the petroleum and coal-tar industries. In this way much information about the properties and reactions of 1,3-butadiene, isoprene, chloroprene, 2,3-dimethylbutadiene-1,3 and 1,4-diphenylbutadiene-1,3 has been accumulated. The subject of this thesis, 2,3-diphenylbutadiene-1,3, has not been studied to any great extent; but, before dealing with this compound in detail, the general reactions of the conjugated dienes will be considered. While some of these hydrocarbons, such as the terpenes ocimene and myrcene, [...] and the carotenoid hydrocarbons occur in nature, and while several of the simpler members can be prepared by the pyrolysis of oils and petroleum, most members of this group must be prepared synthetically. The methods used are generally special cases of those elimination reactions used to prepare ethylenic compounds. A common method is to eliminate the elements of water from a suitable glycol or unsaturated alcohol. [...] This method of preparation is often the most convenient, as the starting materials are generally easy to synthesise. In many cases elimination can take place in more than one way and a mixture of isomers is obtained. [...]