TY - JOUR
T1 - Controlling Selectivity in the Electrocatalytic Hydrogenation of Adiponitrile through Electrolyte Design
AU - Blanco, Daniela E.
AU - Dookhith, Aaliyah Z.
AU - Modestino, Miguel A.
N1 - Funding Information:
The authors would like to acknowledge the support of Dr. Chin Lin at the New York University (NYU) Chemistry Department for the use of the shared NMR spectrometer and Prof. Yoshiyuki Okamoto from the NYU Tandon School of Engineering. The authors also acknowledge the financial support provided by the H&M Foundation through the Global Change Award and from NYU, Tandon School of Engineering, through the MAM startup fund.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/6/22
Y1 - 2020/6/22
N2 - Organic hydrogenations are key steps in the production of numerous valuable chemicals. Their requirement for high temperature, pressure, and compressed hydrogen has motivated the interest to develop safer electrocatalytic hydrogenation (ECH) routes in benign aqueous electrolytes. However, faradaic efficiencies in organic ECH tend to be greatly limited by competition with the hydrogen evolution reaction and low reactant solubility, which hinders the implementation of these more sustainable hydrogenation routes. Using the hydrogenation of adiponitrile to hexamethylenediamine (HMDA), a monomer used in the production of nylon-6,6, as a case study, we investigate the effect of reactant concentration, temperature, pH, and organic cosolvents on the ECH of nitrile groups with Raney nickel electrodes. Higher reactant concentrations, alkaline electrolytes, and mild temperature (40 °C) are key conditions that enhance the hydrogenation of organic substrates against hydrogen evolution. A maximum faradaic efficiency of 92% toward HMDA was obtained in aqueous electrolytes at -60 mA cm-2. The addition of an organic cosolvent is subsequently studied to evaluate the effect of enhanced reactant solubility, achieving a 95% faradaic efficiency at the same current density with 30% methanol by volume in water. The insights gained from this study are relevant for the design of energy efficient organic ECH and can help accelerate the implementation of sustainable chemical manufacturing.
AB - Organic hydrogenations are key steps in the production of numerous valuable chemicals. Their requirement for high temperature, pressure, and compressed hydrogen has motivated the interest to develop safer electrocatalytic hydrogenation (ECH) routes in benign aqueous electrolytes. However, faradaic efficiencies in organic ECH tend to be greatly limited by competition with the hydrogen evolution reaction and low reactant solubility, which hinders the implementation of these more sustainable hydrogenation routes. Using the hydrogenation of adiponitrile to hexamethylenediamine (HMDA), a monomer used in the production of nylon-6,6, as a case study, we investigate the effect of reactant concentration, temperature, pH, and organic cosolvents on the ECH of nitrile groups with Raney nickel electrodes. Higher reactant concentrations, alkaline electrolytes, and mild temperature (40 °C) are key conditions that enhance the hydrogenation of organic substrates against hydrogen evolution. A maximum faradaic efficiency of 92% toward HMDA was obtained in aqueous electrolytes at -60 mA cm-2. The addition of an organic cosolvent is subsequently studied to evaluate the effect of enhanced reactant solubility, achieving a 95% faradaic efficiency at the same current density with 30% methanol by volume in water. The insights gained from this study are relevant for the design of energy efficient organic ECH and can help accelerate the implementation of sustainable chemical manufacturing.
KW - Adiponitrile
KW - Electrocatalytic hydrogenation
KW - Electrohydrogenation
KW - Hexamethylenediamine
KW - Nylon-6,6
KW - Organic electrosynthesis
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U2 - 10.1021/acssuschemeng.0c01789
DO - 10.1021/acssuschemeng.0c01789
M3 - Article
AN - SCOPUS:85086708251
VL - 8
SP - 9027
EP - 9034
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
SN - 2168-0485
IS - 24
ER -