Modeling reduces nickel needed in catalytic reactions | Chemical & Engineering News
Volume 95 Issue 25 | p. 10 | Concentrates
Issue Date: June 19, 2017

Modeling reduces nickel needed in catalytic reactions

Technique adjusts reaction conditions to optimize catalyst use in cross-coupling esterifications
Department: Science & Technology
Keywords: catalysis, nickel, catalysts, cross-coupling, esterification, kinetic modeling
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Loads of nickel

Survey of papers on nickel-catalyzed cross-coupling reactions published from January 2015 to April 2017 shows that most reactions had fairly high nickel-catalyst loadings: 5 to 20 mole %.Source: ACS Catal.
Credit: ACS Catalysis
Chart shows that the vast majority of nickel-catalyzed cross-coupling reactions reported in the literature over a period of a little over two years had fairly high catalyst loadings—5 to 20 mol-%.
 

Loads of nickel

Survey of papers on nickel-catalyzed cross-coupling reactions published from January 2015 to April 2017 shows that most reactions had fairly high nickel-catalyst loadings: 5 to 20 mole %.Source: ACS Catal.
Credit: ACS Catalysis

Nickel catalysts are much less expensive than precious metal catalysts, but the large amounts of nickel catalyst used in many catalytic cross-coupling reactions still discourage industrial adoption. Over roughly the past two years, the vast majority of newly reported nickel-catalyzed cross-coupling reactions required 5 to 20 mole % of nickel catalyst. Neil K. Garg of the University of California, Los Angeles, grad student Nicholas A. Weires, and colleague Daniel D. Caspi of AbbVie have now collaborated to develop a technique that reduces loading (mole percent of catalyst required) in nickel-catalyzed amide esterifications (ACS Catal. 2017, DOI: 10.1021/acscatal.7b01444). They used a kinetic-modeling program, DynoChem, to assess the effect of several variables—ligand-to-metal ratio, reactant stoichiometry, product and by-product generation rate, catalyst temperature-equilibration time, catalyst loading, and reaction concentration—on the rate of benzamide-menthol esterification. They then used the data to develop a kinetic model for the reaction. Use of the model to optimize conditions reduced the 10 mole % nickel catalyst typically required in amide esterifications down to 2 mole %. And using it to tweak a specific benzamide-menthol esterification reduced the reaction’s nickel loading to as little as 0.4 mole %. The researchers hope the approach will help expand industrial use of nickel-catalyzed reactions and the use of kinetic modeling for reaction optimization.

 
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