✍ Scribed by Vayssié, Stéphane ;Elias, Horst
No coin nor oath required. For personal study only.
The kinetics of the reaction of cyclohexene (CH) with an excess of H~2~O~2~ in acetonitrile (AN) at 293 K was studied at variable concentrations of H~2~O~2~ (1.7–13 M), water (1.6–13 M), acids HX (0.2–1.4 M), and salts NaX (0–1.7 M), with HXHClO~4~, H~2~SO~4~, HNO~3~, HPF~6~, p‐toluenesulfonic acid (TSAH), acetic acid (AH), trifluoroacetic acid (TFAH), and benzeneseleninic acid (BSAH). The solvent polarity parameter E~T~(30) of AN/water mixtures was determined. The oxidation of CH by H~2~O~2~, monitored by gas chromatography, was found to be acid‐catalysed. The detailed investigation of the systems CH/HClO~4~/AN and CH/TSAH/AN showed that the reaction is first‐order in CH according to [CH][CH]~0~ exp(–k~exp~·t). At [H~2~O~2~] ⩽ 3 M, the experimental rate constant k~exp~ could be approximated by k~exp~ = k~0~[H~2~O~2~] + k·[H~2~O~2~]·[HX]^2^· [X^−^]~tot~·[H~2~O]^−2^, with k~0~ = (0.93 ± 0.7)·10^−5^ M^−1^s^−1^ and k = (9.65 ± 0.20)·10^−3^ M^−2^s^−1^ for HClO~4~ and k = (5.96 ± 0.10)·10^−3^ M^−2^s^−1^ for TSAH ([X^−^]~tot~ = [NaX] + [HX]). GC analysis of the HClO~4~‐catalysed reaction showed that trans‐cyclohexane‐1,2‐diol (CHD) is a reaction product. The order of catalytic activity of the various acids HX, as derived from the size of k~exp~ obtained under standard conditions, was found to be: AH ≪ HNO~3~ < TFAH < TSAH < HClO~4~ < HPF~6~ < H~2~SO~4~ < BSAH. A mechanistic interpretation is presented and the synthetic potential of the acid‐catalysed oxidation of olefins by H~2~O~2~ is discussed.
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