The surface atomic oxyradical mechanism for Ag-catalyzed olefin epoxidation

Emily A. Carter; William A. Goddard

doi:10.1016/0021-9517(88)90122-4

The surface atomic oxyradical mechanism for Ag-catalyzed olefin epoxidation

Emily A. Carter, William A. Goddard

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100 Scopus citations

Abstract

We report comprehensive, quantitative, ab initio theoretical estimates for the energetics involved in the Ag-catalyzed epoxidation of olefins. From these estimates, a detailed mechanism is proposed. This mechanism (based on theoretical quantum chemical studies of the interaction of atomic and molecular adsorbates with clusters of Ag atoms) proposes that a surface atomic oxyradical anion is the active oxygen species for forming epoxide. This mechanism explains the role of electronegative (Cl^-) and electropositive (Cs⁺) promoters and explains why selectivity (toward epoxide) is far higher for ethylene than for propene and other higher olefins. Recent experiments which suggested O_2(ad) as the active species are reinterpreted within the context of this new atomic oxygen radical mechanism.

Original language	English (US)
Pages (from-to)	80-92
Number of pages	13
Journal	Journal of Catalysis
Volume	112
Issue number	1
DOIs	https://doi.org/10.1016/0021-9517(88)90122-4
State	Published - Jul 1988
Externally published	Yes

All Science Journal Classification (ASJC) codes

Catalysis
Physical and Theoretical Chemistry

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10.1016/0021-9517(88)90122-4

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title = "The surface atomic oxyradical mechanism for Ag-catalyzed olefin epoxidation",

abstract = "We report comprehensive, quantitative, ab initio theoretical estimates for the energetics involved in the Ag-catalyzed epoxidation of olefins. From these estimates, a detailed mechanism is proposed. This mechanism (based on theoretical quantum chemical studies of the interaction of atomic and molecular adsorbates with clusters of Ag atoms) proposes that a surface atomic oxyradical anion is the active oxygen species for forming epoxide. This mechanism explains the role of electronegative (Cl-) and electropositive (Cs+) promoters and explains why selectivity (toward epoxide) is far higher for ethylene than for propene and other higher olefins. Recent experiments which suggested O2(ad) as the active species are reinterpreted within the context of this new atomic oxygen radical mechanism.",

author = "Carter, {Emily A.} and Goddard, {William A.}",

note = "Funding Information: ACKNOWLEDGMENTS This work was initiated and continuedw ith support by the Shell Development Corp. (1982-1985a) nd the Shell CompaniesF oundation( 1985-1987)W. e particularly thank Drs. Charles Adams, Rutger van Santen, and John Cole for their roles in initiating and continuing this industrial support for our research. In addition, the work was partially funded by the National Science Foundation [Grant DMR82-15650(1 983-1986) and Grant CHE83-18041( 1986-1987)]E. AC acknowl-edgesa National Science FoundationP redoctoralF el-lowship (1982-1985)a, researchg rant award from the InternationalP recious Metals Institute and Gemini Industries (1985-1986)a, nd a SOHIO Fellowship in Catalysis (1986-1987)W. e also thank Professors C. T. Campbell and B. E. Koel for useful discussions.",

year = "1988",

month = jul,

doi = "10.1016/0021-9517(88)90122-4",

language = "English (US)",

volume = "112",

pages = "80--92",

journal = "Journal of Catalysis",

issn = "0021-9517",

publisher = "Academic Press Inc.",

number = "1",

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TY - JOUR

T1 - The surface atomic oxyradical mechanism for Ag-catalyzed olefin epoxidation

AU - Carter, Emily A.

AU - Goddard, William A.

N1 - Funding Information: ACKNOWLEDGMENTS This work was initiated and continuedw ith support by the Shell Development Corp. (1982-1985a) nd the Shell CompaniesF oundation( 1985-1987)W. e particularly thank Drs. Charles Adams, Rutger van Santen, and John Cole for their roles in initiating and continuing this industrial support for our research. In addition, the work was partially funded by the National Science Foundation [Grant DMR82-15650(1 983-1986) and Grant CHE83-18041( 1986-1987)]E. AC acknowl-edgesa National Science FoundationP redoctoralF el-lowship (1982-1985)a, researchg rant award from the InternationalP recious Metals Institute and Gemini Industries (1985-1986)a, nd a SOHIO Fellowship in Catalysis (1986-1987)W. e also thank Professors C. T. Campbell and B. E. Koel for useful discussions.

PY - 1988/7

Y1 - 1988/7

N2 - We report comprehensive, quantitative, ab initio theoretical estimates for the energetics involved in the Ag-catalyzed epoxidation of olefins. From these estimates, a detailed mechanism is proposed. This mechanism (based on theoretical quantum chemical studies of the interaction of atomic and molecular adsorbates with clusters of Ag atoms) proposes that a surface atomic oxyradical anion is the active oxygen species for forming epoxide. This mechanism explains the role of electronegative (Cl-) and electropositive (Cs+) promoters and explains why selectivity (toward epoxide) is far higher for ethylene than for propene and other higher olefins. Recent experiments which suggested O2(ad) as the active species are reinterpreted within the context of this new atomic oxygen radical mechanism.

AB - We report comprehensive, quantitative, ab initio theoretical estimates for the energetics involved in the Ag-catalyzed epoxidation of olefins. From these estimates, a detailed mechanism is proposed. This mechanism (based on theoretical quantum chemical studies of the interaction of atomic and molecular adsorbates with clusters of Ag atoms) proposes that a surface atomic oxyradical anion is the active oxygen species for forming epoxide. This mechanism explains the role of electronegative (Cl-) and electropositive (Cs+) promoters and explains why selectivity (toward epoxide) is far higher for ethylene than for propene and other higher olefins. Recent experiments which suggested O2(ad) as the active species are reinterpreted within the context of this new atomic oxygen radical mechanism.

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JO - Journal of Catalysis

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The surface atomic oxyradical mechanism for Ag-catalyzed olefin epoxidation

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