Catalytic Effect of Potassium Xanthates and Related Compounds on Disulfide Bond Enrichment of Polyalkylene Sulfides Synthesized in the Course of Episulfide Polymerization.

The original method for the preparation of high-molecular-weight polyalkylene sulfides was reported. Assuming anomalous peculiarities of the reaction (high polymerization rates, high degrees of polymerization, and huge discrepancy between the expected values and the experimentally obtained values), the priority task was set to study the mechanism underlying the observed new type of polymerization. Thus, it was demonstrated that xanthate and related molecules could act as pure catalysts, facilitating both the chain-growth polymerization (ring-opening of episulfides) realized via an anionic route and the direct attack of the sulfur atom of one episulfide molecule on the methylene carbon atom of the second (neighbor) episulfide molecule, accompanied by the subsequent formation of a stable thiiranium-based zwitterionic adduct.

Effect of Water on the Activation Thermodynamics of Deep Eutectic Solvents Based on Carboxybetaine and Choline.

Thermodynamic characteristics as well as peculiarities of hydrogen bonding in aqueous solutions of new deep eutectic solvents (DES) based on synthetic carboxybetaine have been studied. Cheap starting reagents (acrylic acid and 2-dimethylaminoethanol), simple preparation, and high yields are the advantages of the proposed betaine. Analyses of the calculated stabilization energies and natural bond orbital delocalization energies revealed the absence of preferential association in aqueous reline solutions tested for the comparative purpose.