Susan J. Babinec

The effect of cathode composition on the efficiency of electrocarboxylation of aromatic halides

The composition of the cathode has a significant effect on the efficiency of electrocarboxylation of aromatic halides which are relatively difficult to reduce in N,N-dimethylformamide. At low temperatures (< 0°C) and controlled current conditions, aromatic bromides and iodides are carboxylated with much greater efficiency than aromatic chlorides at a silver electrode, while at stainless steel the chlorides are carboxylated more efficiently. At silver the efficiency depends on the ease of reduction of the halides relative to CO2, while at stainless steel passivation effects, which are more serious for the bromides and iodides, primarily influence the efficiency. Experiments with added D2O provide no evidence for production of aromatic radical intermediates via CO2-mediated one-electron reduction of the halides.

Multicomponent Materials as Li+ Conductors

The conductivity and mechanical stiffness of ethylene-oxide based Li + conducting solid polymer electrolytes (SPE) were measured and compared for a variety of single- and two-phase systems. Our objective was to determine whether there are simple correlations between these two properties despite the fact that these systems are truly complex. Results show that molecular architecture dominates both transport and mechanical behavior of single phase systems, thereby eliminating broad correlations. Conductivity was additionally found to require not only facile local chain dynamics but also a sufficient concentration of vacancies, as per the site hopping model. Two phase systems also show complex behaviors, but offer a broader range of both conductivity and stiffness values, and good conductivity/stiffness correlations.