Electrochemical Synthesis of Adiponitrile from Acrylonitrile and Glutamic Acid

Adiponitrile (ADN) is a colorless and oily liquid used as a corrosion inhibitor, solvent, and rubber accelerator. Additionally, ADN is a precursor of hexamethylenediamine, which is a monomer used in manufacturing of Nylon 6,6. The variety of uses of this strand of nylon in electronic, automotive, chemical, and healthcare sectors leads to the growing demand for ADN, which is considered the bottleneck for the nylon production. The thermochemical hydrocyanation of 1,3 butadiene is the most commonly used method for ADN production, which requires large amounts of energy and the use of hydrogen cyanide, a highly toxic reactant. Due to environmental concerns and declining fossil fuel supplies, it is necessary to find efficient methods of deriving ADN from renewable resources. Two alternative methods show promise of renewable electrochemical production of ADN. The first method is the hydrodimerization of acrylonitrile (AN). This study focuses on the steric effects in the selectivity and production rates of the dimerization of β–substituted AN (i.e., crotononitrile). The results enable a better understanding of the effect of radical stability of intermediates and geometric effects in the product distribution of hydrodimerization reactions. The second method is biomass-based synthesis of ADN via Kolbe coupling of 3-cyanopropanoic acid (CPA). The effects of solvent composition and potential in the product distribution of Kolbe dimerization of CPA are explored. The overarching goal of this study is to provide insights of the factors that control selectivity and rates of multiple reaction pathways for the electrosynthesis of ADN and its derivatives.