Pressure Dependence of the Carbon Dioxide/Cyclohexene Oxide Coupling Reaction Catalyzed by Chromium Salen Complexes. Optimization of the Comonomer-Alternating Enchainment Pathway

Autor:	Damon R. Billodeaux, Ryan M. Mackiewicz, Donald J. Darensbourg
Rok vydání:	2004
Předmět:	Comonomer Organic Chemistry Inorganic chemistry Epoxide chemistry.chemical_element Coupling reaction Catalysis Inorganic Chemistry chemistry.chemical_compound Chromium chemistry Carbon dioxide Physical and Theoretical Chemistry Bar (unit) Cyclohexene oxide
Zdroj:	Organometallics. 24:144-148
ISSN:	1520-6041 0276-7333
DOI:	10.1021/om049454l
Popis:	The rate of the copolymerization reaction of cyclohexene oxide and carbon dioxide in the presence of (salen)CrIIIN3 and various cocatalysts has been determined as a function of CO2 pressure. Carbon dioxide insertion into the (salen)Cr-alkoxide intermediates, afforded following epoxide ring-opening, was shown to be rate-limiting at pressures below 35 bar. Higher pressures of carbon dioxide resulted in catalyst/substrate dilution with a concomitant decrease in the rate of copolymer formation. On the other hand, cyclic carbonate formation was inhibited as the CO2 pressure was increased. The most active (salen)CrN3 catalyst (H2salen = N,N‘-bis(3-tert-butyl-5-methoxysalicylidene)-(1R,2R)-cyclohexenediimine), along with a [PPN][N3] cocatalyst, exhibited a TOF of 1153 mol epoxide consumed/mol chromium·h at 80 °C and a CO2 pressure of 34.5 bar.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7fb7cab3bca7ea55adb58e9c6d057ebe https://doi.org/10.1021/om049454l Zobrazit plný text záznamu