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By applying [13]C and [1]H NMR spectroscopy the pyrolysis of site-selectively [13]C-enriched (H3[13]CO[12]C6H5) and normal anisole compounds was studied in the dark at 0.001–1.0 M (M, mol dm[−3]) and at 400–600 °C (supercritical conditions). Conversion of the [13]C-labeled methyl group was confined to the methoxy-originated fragments, [13]CO and [13]CH4, and the reactive intermediate, H[13]CHO*. The normal phenyl group, [12]C6H5– was converted to benzene, [12]C6H6 and phenol, [12]C6H5OH without ring disintegration. The pyrolysis consists of two elementary steps: (1) the rate-determining unimolecular ether-bond fission (k1) to generate the fragmented product C6H6 and energized intermediate H[13]CHO* through the intramolecular proton transfer from the methoxy group to the phenyl, and (2) the fast bimolecular disproportionation (k2) through the intermolecular proton/hydride transfer from H[13]CHO* to H3[13]COC6H5 to produce [13]CO, [13]CH4, and C6H5OH. CO is generation by the heterolytic (ionic) mechanism in contrast to the homolytic (radical) one via the phenoxy radical intermediate (C6H5O•) in the literature despite the agreement of the rate constant (k1) and the activation energy.

Hydrothermal decomposition of a hazardous chlorinated organic compound, dichloromethane, has been investigated using in-situ NMR spectroscopy. It is found that the hydrolysis of dichloromethane yields methanediol as an intermediate. Methanediol is a hydrated form of formaldehyde and easily transformed into methanol and formic acid under basic conditions. In the temperature range of 70-140 °C, the Cannizzaro-type reaction occurs: methanediol produces the reduced form, methanol and the oxydized form, formic acid. At higher temperatures between 200 and 250 °C, on the other hand, two methanediol molecules form glycolic acid which has a new C-C bond. The reaction rate constants and activation energies for the dechlorination and the Cannizzaro-type reactions have been obtained.

In water at 250 °C and 4 MPa, methanol and formic acid are produced from the disproportionation reaction of formaldehyde without a catalyst, although at mild conditions, this reaction usually occurs in the presence of a large amount of base catalyst. Formic acid further undergoes the hydride transfer reaction with formaldehyde, and the final yield of methanol exceeds 50%.