Esterification alkyl-oxygen fission

These sulphonate esters cannot be made by direct esterification of the sulphonic acids since further reaction of the ester with the alcohol gives rise to an ether by means of an alkyl-oxygen fission process. 

Praill, having discovered the efficiency of acylium perchlorates as acylating agents, decided to examine the esterification of /err-butanol as opposed to its dehydration to isobutene. Using acetic anhydride and perchloric acid mixtures, both tert-h xty acetate and isobutene were rapidly produced and in accordance with the known alkyl oxygen fission of tertiary esters, the proportion of isobutene increased with time. In these reactions where acetic anhydride was in excess, crystalline material was deposited in the mixture. Later this was shown to be 2,4,6-trimethylpyrylium perchlorate, identified by its conversion to 2,4,6-trimethyl pyridine and its picrate. When isobutene itself was acylated using acetic anhydride and perchloric... 

Sulfuric acid reacts with primary and secondary alcohols by a bimo-lecular displacement reaction with no alkyl-oxygen fission. The mechanism of the reaction is similar to the acid-catalyzed esterification of carboxylic acids. Sulfation of optically active 2-butanol gives a sulfate ester with complete retention of configuration. In addition, neopentyl alcohol sulfates without rearrangement. 

The mechanism and kinetics of the sulfation of the lower alcohols with sulfuric acid have been studied. The reaction proceeds by a bimolecular displacement mechanism like that of the acid-catalyzed esterification of alcohols with carboxylic acids no oxygen-alkyl fission occurs. Neopentyl alcohol sulfates at a rate comparable to other secondary alcohols these results indicate that within the groups of primary and secondary alcohols steric effects are minor. However, primary alcohols sulfate at a rate ten times that of secondary alcohols. The experimentally determined rate law... 

---