The synthesis of pure hydrocarbons

Abstract

The work began with the preparation of aliphatic hydrocarbons for the measurement of their physical properties. The hydrocarbons prepared were: 1) 3:4-Dimethylnonane 2) 4:5-Dimethylnonane 3) 2:6-Dimethyloctane. The preparation of 2:4:4-Trimethylhexane was attempted, the ketone 2:4:4-Trimethylhexan-3-ene being the required intermediate. The preparation of this was attempted by the reaction between isobutyramide and tert-amylmagnesium bromide. The product, at first thought to be the ketone, showed that an investigation of this reaction would prove interesting. A series of reactions was then carried out between five aliphatic acid amides and Grignard reagents prepared from five alkyl halides. The results are stated in Part V of the thesis and discussed in Part IV. The following conclusions have been drawn from the results obtained:- 1) The amide reacts with the Grignard reagent in the keto form and not in the imino-alcohol form, as suggested by previous workers. An ionic mechanism is thought to summarize most successfully the results obtained. 2) The amide causes the decomposition of the Grignard. reagent. This is shown by the volume of gas evolved, the fact that some of this volume is unsaturated, and the presence of saturated and unsaturated hydrocarbonsin the liquid products. The reactions of acetamide are discussed. Here the product is the condensed nitrile cyanmethine. The mechanism is thought to be similar to that of other amides in the first stage.