188 research outputs found

    Kinetic and economic analysis of reactive capture of dilute carbon dioxide with Grignard reagents

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    Carbon Dioxide Utilisation (CDU) processes face significant challenges, especially in the energetic cost of carbon capture from flue gas and the uphill energy gradient for CO2 reduction. Both of these stumbling blocks can be addressed by using alkaline earth metal compounds, such as Grignard reagents, as sacrificial capture agents. We have investigated the performance of these reagents in their ability to both capture and activate CO2 directly from dried flue gas (essentially avoiding the costly capture process entirely) at room temperature and ambient pressures with high yield and selectivity. Naturally, to make the process sustainable, these reagents must then be recycled and regenerated. This would potentially be carried out using existing industrial processes and renewable electricity. This offers the possibility of creating a closed loop system whereby alcohols and certain hydrocarbons may be carboxylated with CO2 and renewable electricity to create higher-value products containing captured carbon. A preliminary Techno-Economic Analysis (TEA) of an example looped process has been carried out to identify the electrical and raw material supply demands and hence determine production costs. These have compared broadly favourably with existing market values

    Tandem application of C-C bond-forming reactions with reductive ozonolysis

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    Several variants of reductive ozonolysis, defined here as the in situ generation of aldehydes or ketones during ozonolytic cleavage of alkenes, are demonstrated to work effectively in tandem with a number of C-C bond-forming reactions. For reactions involving basic nucleophiles (1,2- addition of Grignard reagents, Wittig or Horner-Emmons olefinations, and directed Aldol reactions of lithium enolates) the one-pot process offers a rapid and high-yielding alternative to traditional two-step protocols

    Iron-catalyzed reactions of Grignard reagents

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    4 - Chapitre de livr

    Iron-catalyzed oxidative heterocoupling between aliphatic and aromatic organozinc reagents: a novel pathway for functionalized aryl-alkyl cross-coupling reactions

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    1 - ArticleAryl-alkyl cross-coupling products are obtained by the iron-catalyzed oxidative heterocoupling of organozinc reagents under mild conditions. This novel reaction pathway is versatile, allowing for the use of primary and secondary aliphatic diorganozinc reagents as coupling partners as well as tolerating functionalized aryl- and alkylzinc reagents

    Manganese-catalyzed cross-coupling reaction between aryl Grignard reagents and alkenyl halides

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    1 - ArticleAryl Grignard reagents react stereospecifically with alkenyl halides in the presence of manganese chloride (10%) to afford good yields of cross-coupling products

    Iron-catalyzed alkylation of alkenyl Grignard reagents

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    1 - ArticleThe first iron-catalyzed cross-coupling reaction between alkenyl Grignard reagents and n- or s-alkyl bromides is described. The reaction is stereoselective and takes place in the presence of 5 mol % of [Fe(acac)(3)/TMEDA/HMTA] (1:2:1) under very mild conditions (THF, 0 degrees C, 45 min)

    Stereoselective preparation of dienol phosphates from alpha,beta-ethylenic aldehydes

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    1 - ArticleThe first stereoselective method of preparation of (E)-dienol phosphates from alpha,beta-ethylenic aldehydes is described. The key point is the stereoselective enolization of conjugated alkenals by potassium tert-butoxide in the presence of N-methylpyrrolidinone (NMP)
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