Catalyst structure and substituent effects on epoxidation of styrenics with immobilized Mn(tmtacn) complexes

Patricia Anne A Ignacio-De Leon, Christian A. Contreras, Nicholas E. Thornburg, Anthony B. Thompson, Justin M Notestein

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Monomeric and dimeric complexes of Mn 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) were immobilized under reaction conditions onto solid supports to create heterogeneous catalysts for epoxidation with H2O2. These solid supports consist of activated carbon or silica grafted or co-condensed with benzoic or C3/C4 acids that function both as tethering points and as required co-catalysts. Immobilized catalysts were as much as 50-fold faster than the analogous soluble system, and an immobilized, dimeric Mn(tmtacn) complex with a solid benzoic acid co-catalyst gave the highest yields to epoxide. A Hammett study on the catalytic epoxidation of a series of styrenes showed weak increases in yield for more electron-withdrawing p-substituents reactants for both immobilized complexes, which runs counter to previous observations with analogous homogeneous catalysts, and which appears to reflect a previously unappreciated tradeoff between the intrinsic epoxidation reactivity and strong catalyst inhibition by styrene oxides and glycols. Finally, these catalysts were tested with a variety of solid-co-catalysts, and were successfully utilized in the challenging epoxidation of divinylbenzene to industrially-useful divinylbenzene dioxide using a cascade of two catalyst charges.

Original languageEnglish
Pages (from-to)78-86
Number of pages9
JournalApplied Catalysis A: General
Volume511
DOIs
Publication statusPublished - Feb 5 2016

Fingerprint

Epoxidation
Catalysts
divinyl benzene
styrene oxide
Catalyst supports
Styrene
Styrenes
1,4,7-trimethyl-1,4,7-triazacyclononane
Benzoic Acid
Benzoic acid
Epoxy Compounds
Glycols
Silicon Dioxide
Activated carbon
Silica
Acids
Oxides
Electrons

Keywords

  • Epoxidation
  • Hammett relationships
  • Hydrogen peroxide
  • Manganese
  • Supported catalyst

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology

Cite this

Catalyst structure and substituent effects on epoxidation of styrenics with immobilized Mn(tmtacn) complexes. / Ignacio-De Leon, Patricia Anne A; Contreras, Christian A.; Thornburg, Nicholas E.; Thompson, Anthony B.; Notestein, Justin M.

In: Applied Catalysis A: General, Vol. 511, 05.02.2016, p. 78-86.

Research output: Contribution to journalArticle

Ignacio-De Leon, Patricia Anne A ; Contreras, Christian A. ; Thornburg, Nicholas E. ; Thompson, Anthony B. ; Notestein, Justin M. / Catalyst structure and substituent effects on epoxidation of styrenics with immobilized Mn(tmtacn) complexes. In: Applied Catalysis A: General. 2016 ; Vol. 511. pp. 78-86.
@article{472fc7252ab74839b8bae06bfd8a3318,
title = "Catalyst structure and substituent effects on epoxidation of styrenics with immobilized Mn(tmtacn) complexes",
abstract = "Monomeric and dimeric complexes of Mn 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) were immobilized under reaction conditions onto solid supports to create heterogeneous catalysts for epoxidation with H2O2. These solid supports consist of activated carbon or silica grafted or co-condensed with benzoic or C3/C4 acids that function both as tethering points and as required co-catalysts. Immobilized catalysts were as much as 50-fold faster than the analogous soluble system, and an immobilized, dimeric Mn(tmtacn) complex with a solid benzoic acid co-catalyst gave the highest yields to epoxide. A Hammett study on the catalytic epoxidation of a series of styrenes showed weak increases in yield for more electron-withdrawing p-substituents reactants for both immobilized complexes, which runs counter to previous observations with analogous homogeneous catalysts, and which appears to reflect a previously unappreciated tradeoff between the intrinsic epoxidation reactivity and strong catalyst inhibition by styrene oxides and glycols. Finally, these catalysts were tested with a variety of solid-co-catalysts, and were successfully utilized in the challenging epoxidation of divinylbenzene to industrially-useful divinylbenzene dioxide using a cascade of two catalyst charges.",
keywords = "Epoxidation, Hammett relationships, Hydrogen peroxide, Manganese, Supported catalyst",
author = "{Ignacio-De Leon}, {Patricia Anne A} and Contreras, {Christian A.} and Thornburg, {Nicholas E.} and Thompson, {Anthony B.} and Notestein, {Justin M}",
year = "2016",
month = "2",
day = "5",
doi = "10.1016/j.apcata.2015.12.002",
language = "English",
volume = "511",
pages = "78--86",
journal = "Applied Catalysis A: General",
issn = "0926-860X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Catalyst structure and substituent effects on epoxidation of styrenics with immobilized Mn(tmtacn) complexes

AU - Ignacio-De Leon, Patricia Anne A

AU - Contreras, Christian A.

AU - Thornburg, Nicholas E.

AU - Thompson, Anthony B.

AU - Notestein, Justin M

PY - 2016/2/5

Y1 - 2016/2/5

N2 - Monomeric and dimeric complexes of Mn 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) were immobilized under reaction conditions onto solid supports to create heterogeneous catalysts for epoxidation with H2O2. These solid supports consist of activated carbon or silica grafted or co-condensed with benzoic or C3/C4 acids that function both as tethering points and as required co-catalysts. Immobilized catalysts were as much as 50-fold faster than the analogous soluble system, and an immobilized, dimeric Mn(tmtacn) complex with a solid benzoic acid co-catalyst gave the highest yields to epoxide. A Hammett study on the catalytic epoxidation of a series of styrenes showed weak increases in yield for more electron-withdrawing p-substituents reactants for both immobilized complexes, which runs counter to previous observations with analogous homogeneous catalysts, and which appears to reflect a previously unappreciated tradeoff between the intrinsic epoxidation reactivity and strong catalyst inhibition by styrene oxides and glycols. Finally, these catalysts were tested with a variety of solid-co-catalysts, and were successfully utilized in the challenging epoxidation of divinylbenzene to industrially-useful divinylbenzene dioxide using a cascade of two catalyst charges.

AB - Monomeric and dimeric complexes of Mn 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) were immobilized under reaction conditions onto solid supports to create heterogeneous catalysts for epoxidation with H2O2. These solid supports consist of activated carbon or silica grafted or co-condensed with benzoic or C3/C4 acids that function both as tethering points and as required co-catalysts. Immobilized catalysts were as much as 50-fold faster than the analogous soluble system, and an immobilized, dimeric Mn(tmtacn) complex with a solid benzoic acid co-catalyst gave the highest yields to epoxide. A Hammett study on the catalytic epoxidation of a series of styrenes showed weak increases in yield for more electron-withdrawing p-substituents reactants for both immobilized complexes, which runs counter to previous observations with analogous homogeneous catalysts, and which appears to reflect a previously unappreciated tradeoff between the intrinsic epoxidation reactivity and strong catalyst inhibition by styrene oxides and glycols. Finally, these catalysts were tested with a variety of solid-co-catalysts, and were successfully utilized in the challenging epoxidation of divinylbenzene to industrially-useful divinylbenzene dioxide using a cascade of two catalyst charges.

KW - Epoxidation

KW - Hammett relationships

KW - Hydrogen peroxide

KW - Manganese

KW - Supported catalyst

UR - http://www.scopus.com/inward/record.url?scp=84949032943&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84949032943&partnerID=8YFLogxK

U2 - 10.1016/j.apcata.2015.12.002

DO - 10.1016/j.apcata.2015.12.002

M3 - Article

VL - 511

SP - 78

EP - 86

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

SN - 0926-860X

ER -