Carboxylate formation

A second requirement of the Tronov postulates—formation of acid anhydrides—is met by evidence from infrared spectra of oxidized coal samples periodically withdrawn from the reactor. As a matter of experimental record, it should be observed that such anhydrides did not appear until the later stages of reaction, by which time -COOH concentrations were already quite high. However, since initial carboxyl formation probably occurs in aliphatic structures present in the parent coal (9), appearance of anhydrides after rather... 

While studying the reaction of adamantane with carbon monoxide under super-acidic catalysis, formylation (formation of 1-adamantanecarboxaldehyde) was found by Olah and co-workers447 to effectively compete with Koch—Haaf carboxylation (formation of 1-adamantanecarboxylie acid, major product formed in 60-75% yield). On the basis of results acquired by the reaction of 1,3,5,7-tetradeuteroadamantane, formylation was interpreted by insertion of the formyl cation into the tertiary C—H cr-bond [Eq. (5.163)]. 

Apart from the effect of pure inorganic salts, Pandya et al. (1993) studied two series of electrolytes, one with increasing anion size (carboxylates formate, acetate, propionate, butyrate, valerate, caproate, caprylate) and the other with increasing cation size (tetraalkylammonium ions methyl,... 

Ketones and nitriles are rather soft bases their coordination onto electron-deficient sites on oxides is, therefore, relatively weak. One may, however, expect an improved specificity of chemisorption due to their softness. Unfortunately, however, these substances very easily undergo chemical transformations at oxide surfaces. Thus, carboxylate structures are formed on adsorption of acetone on alumina (194, 245-247), titanium dioxide (194), and magnesium oxide (219, 248, 249). Besides, acetone is also coordinated onto Lewis acid sites. A surface enolate species has been suggested as an intermediate of the carboxylate formation (248, 249). However, hexafluoroacetone also leads to the formation of trifluoroacetate ions (219). The attack of a basic surface OH ion may, therefore, be envisaged as an alternative or competing reaction path ... 

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