Improved method for the Wacker oxidation of cyclic and internal olefins

Miller, D. G.; Wayner, Danial D. M.

doi:10.1021/jo00296a067

Cited by 120 publications

(45 citation statements)

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“…Comparison of 1-decene oxidations in 0.015 M HCIO, ( confirmed, as was found for the homogeneous reaction (12), that the reaction rate increased as the concentration of perchloric acid increased. Once a steady state has been achieved the measured current is proportional to the overall rate.…”

Section: Resultssupporting

confidence: 63%

“…This rate enhancement of a factor of ca. 2 is less than that found in the homogeneous reaction using a stoichiometric amount of BQ (abbut a factor of 5) (12).…”

Section: Resultsmentioning

confidence: 65%

“…One possibility is to replace one of the homogeneous oxidation reactions with an electrochemical reaction. Direct electro-oxidation of Pd (0) is not practical since the metal forms a mirror over the apparatus ( 12,13). However, it is feasible to consider using only catalytic amounts of a homogeneous chemical oxidant to recycle the palladium and to regenerate the chemical oxidant from its reduced form electrocheniically (eq.…”

Section: Introductionmentioning

confidence: 99%

“…However, it is well known that chloride significantly inhibits the reaction (1,6). Recent work in our laboratory (12) demonstrated that the homogeneous olefin oxidation was accelerated by as much as a factor of 40 by the addition of acid and the exclusion of chloride. Hence, we expected that improvements in the electrode-mediated oxidation process could be attained by using a completely chloride-free system in which a non-complexing (i.e., strong) acid was added.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we have examined the controlled potential electrode-mediated oxidation of terminal, internal, and cyclic olefins, using this acid-enhanced, chloride-free method ( 12). Benzoquinone (BQ) has been used to reoxidize the Pd(0) (eq.…”

Section: Introductionmentioning

confidence: 99%

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Electrode-mediated Wacker oxidation of cyclic and internal olefins

Miller¹,

Wayner²

1992

Can. J. Chem.

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An improved method for the elcctrode-mcdiated oxidations of olefins by palladium(I1) is dcscribed. Current efficiencies from 80% to 95% werc obtained in oxidations of I-dcccnc, styrene, tt.trtls-2-octcne, and cyclohexene in which pcrchloric acid was added to a chloride-free solution of a palladiun~(I1) acctate catalyst. The palladiunl(0) was reoxidized to palladium(I1) by reaction with catalytic amounts of benzoquinone, which was, in turn, regenerated by anodic oxidation. Addition of varying amounts of pcrchloric acid did not affect the current efficiency but accelerated the oxidation reaction, up to a concentration of approximately 0. I5 M. Thc current efficiency remained high (>80%) over the course of the electrode-mediated oxidations of I-decene, trcltls-2-octcne, and cyclohexenc. At thc end of the reactions. when the substrate was depleted, a drastic dccrease in the current was observed, indicating that the catalytic cycle leading to product was primarily responsible for the electrochemical reaction. It also was shown that the rates of the electrochemical reactions were generally slower than those of homogeneous reactions in which a stoichiometric amount of benzoquinone was used, indicating that the elcctroche~nical regeneration of benzoquinonc was mass transport limited at the highest concentrations of pcrchloric acid. This is in contrast to othcr rcports in the literature that suggested that the homogencous (non-electrochemic:~l) reactions were actually slower. Reasons for the discrepancy betwccn thesc results arc discussed. pour I'ensemble des oxydations assistees par une Clcctrode. A la fin de reactions, lorsqu'il ne reste plus de substrat, on observe une dra~natique diminution du courant qui indique que le cycle catalytique conduisant au produit est le principal responsable de la rtaction Clectrochimique. On a montrC que la vitesse des reactions electrochimiq~~es est g&n&ralement plus lentc que les reactions homogenes dans lesquelles on utilise unc quantitd stocchiornttrique de benzoquinone; ceci i n d i q~~e que, 5 des concentrations ClevCes d'acide perchlorique, la rCgCndration clectrochi~nique de la benzoquinonc est li~nittc par un transport de Iiiasse. Cctte situation est en opposition avcc d'autrcs rapports parus dans la littkrature qui suggeraient que Ics reactions homogiines (non-Clectrocliin~iq~~es) sont clc fait plus Icntcs. On discute des raisons pouvant expliquer ccs diff6rcnces.[Traduit par la redaction]

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Section: Resultssupporting

confidence: 63%

“…This rate enhancement of a factor of ca. 2 is less than that found in the homogeneous reaction using a stoichiometric amount of BQ (abbut a factor of 5) (12).…”

Section: Resultsmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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