The reaction mechanism of the Kolbe-Schmitt reaction of phenol and 2-naphthol has been investigated. An alkali metal phenoxide-CO2 complex is not an intermediate that can be easily transformed into a carboxylic acid, such as salicylic acid (SA) and p-hydroxybenzoic acid (pHBA). A direct carboxylation of phenoxide with CO2 takes place even at room temperature, and is competitive with the formation of the CO2 complex. The resulting complex decomposes thermally (above ca. 100 degrees C) to phenoxide, which then undergoes further competitive reactions. Experiments using a carbon-13 labeled complex support a mechanism of direct carboxylation, and not the mechanism via a CO2 complex. The reactivity, C-13 NMR and MOPAC/PM3 calculations suggest a new carbonate-like structure for the CO2 complex.

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It was found that the carboxylations of magnesium, calcium, and barium phenoxides with carbon dioxide at 260 °C produced salicylic acid and dicarboxylic acids (4-hydroxyisophthalic acid and 2-hydroxyisophthalic acid) in very high yields (80–100%), exceeding that of the ordinary Kolbe–Schmitt reaction. The orientation (ortho/para ratio) was controlled not only by chelations of the intermediate with alkaline earth metal (Mg, Ca, Ba) ions, resulting in salicylic acid, but also by the sizes of metal ions (Rb, Cs), giving p-hydroxybenzoic acid in a much higher ratio than the widely used method with potassium or sodium phenoxide. These alkaline earth metals worked to produce 3-hydroxy-2-naphthoic acid by the reaction of 2-naphthoxide with carbon dioxide, but the yield of 6-hydroxy-2-naphthoic acid was comparable to that of 3-hydroxy-2-naphthoic acid when cesium or rubidium 2-naphthoxide was employed. Considerably high yields (∼60%) of 6-hydroxy-2-naphthoic acid, a monomer of one of the best liquid-crystal polymers, was attained by the carboxylation of cesium or rubidium 2-naphthoxide in the presence of potassium or sodium carbonate, where the alkali metal ion was supposed to increase the reactivity of the substrate. The formation of “binol” was observed in the preparation of 2-naphthoxides with metal hydroxides, especially with copper(II) ion.

A convenient one-pot−two-step process for chemical recycling of waste PET to produce terephthalohydroxamic acid (TPHA) and terephthalohydrazide (TPHD) was proposed. Decomposition of PET pellets to the corresponding oligomeric mixture in boiling ethylene glycol, followed by its treatment with hydroxylamine and hydrazine at room temperature in 1 h, produced >90% overall yields of TPHA and TPHD, respectively.

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The vapor-phase photobromination of 1-bromobutane with molecular bromine (5:1) yields 11 products resulting from direct substitution or the elimination of a bromine atom from the 1 -(bromomethyl)propyl radical. The 1 -butene resulting from elimination undergoes addition, and allylic substitution and addition to yield polyhalogenated materials. The major portion of the bromine (65% ) produced 1,2,3-tribromobutane and 1,2,3,4-tetrabromobutane. Bromination with bromine-81 produced isotopically enriched products which were consistent with the proposed mechanism and showed that 33% of the 1,2-dibromobutane formed arose from the elimination-readdition process. Vapor phase photobromination carried out to partial completion with high concentrations of bromine and hydrogen bromide resulted in only minimal amounts of 0 scission of the 1 -(bromomethyl)propyl radicals. Under these conditions the bromination of perdeuterio-1-bromobutane allowed the determination of the relative rates of transfer, with bromine and hydrogen bromide, of the radicals formed in the reaction and further allowed the determination of the relative rates of abstraction at each position in the molecule. The relative rates of transfer and abstraction indicate that the radical formed 0 to the electronegative bromine atom is stabilized (i.e., more easily formed and less reactive with hydrogen bromide) compared to those in the other positions in the molecule.

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