Sludge Test

I have continued to investigate the dehydration of methylcyclohexanols this summer. Just for fun, I have neutralized the “still pot” solution with sodium bicarbonate after the distillation has taken place. In theory, the still pot solution contains phosphoric acid, unreacted alcohol, and undistilled alkenes. After the acid catalyzed dehydration of a methylcyclohexanoel, the methy t-butylether extract of the neutralized still pot was analyzed by GC-MS. The major components seemed to be a group of closely related high-boiling point compounds. The obvious identity of these compounds is that they are dimers created by carbocation reaction with alkenes. The Single Ion Monitoring MS for the still pot compounds from the phosphoric acidimerd catalyzed dehydration of 1-methyl-1-cyclohexanol shows two prominent peaks at m/z 192, that have m/z 96 fragments. This supports the formation of carbocation intermediates for the overall dehydration reaction.

GC-MS_dimers

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