The reactions of glyoxal with ammonia, ammonium salts, and amines cause the formation of the secondary organic aerosol (SOA) components (imidazole and its derivatives) in the atmosphere. The interaction of glyoxal and ammonia in aqueous solution is a primary reaction for these processes, and the explanation of its mechanism will allow developing the methods to control the formation of the SOA components. A detailed mechanism for the formation of key intermediates, namely, ethanediimine, diaminoethanediol, and aminoethanetriol, required for the imidazole ring cyclization, is proposed, and its potential energy surface (PES) has been constructed. This mechanism includes the experimentally identified intermediate compounds and takes into account the conformational and hydration equilibria of glyoxal. The schemes are proposed for further conversion of the key intermediates to the products of condensation between glyoxal and ammonia in the aqueous solution, C–N cyclic oligomers, that were identified. The products are shown to correspond to low positions on the PES in terms of Gibbs free energy, from −30.8 to −68.3 kcal mol⁻¹, which confirms the high probability of their formation. The preferable thermodynamic pathway for formation of the imidazole products does not comprise the conversion of the diimine intermediate with the participation of the proton, but rather the interaction of either the diaminoalcohol with glyoxal monohydrate or two monoamine derivatives between themeselves (aminoethantriol and aminohydroxyacetaldehyde).

Представлены результаты исследования техногенной сейсмичности, возникшей в районе добычи угля открытым способом на территории Новосибирской области. Интенсивность разработки Горловского угольного месторождения существенно выросла в последнее десятилетие, соответственно формируется сейсмическая активизация недр Горловской впадины в ответ на техногенное воздействие. Землетрясения с магнитудой 4.5, ощутимые в г. Новосибирске и его пригородах, фиксируются в районе месторождения, начиная с 2019...

The most thermodynamically and kinetically favorable pathways for the formation of 2-methylimidazole (2MI) in the reaction of glyoxal and acetaldehyde with ammonia in aqueous solution have been determined. The formation of 2MI proceeds through a number of successive intermediates of acyclic and cyclic structures, and the most favorable route (thermodynamically and kinetically) for the formation of the imidazole ring is the condensation of amine intermediates, in contrast to the existing concepts of imine structures. The limiting stage is the stage of cyclization involving the intramolecular attack by the amino group of the precyclic intermediate on the carbon atom bound to the hydroxyl group with the simultaneous release of a water molecule according to the S_N2 mechanism. Further stages of stepwise dehydration lead to the formation of a cyclic diazine, the intramolecular migration of the proton of the tertiary carbon atom to the nitrogen atom of which completes the formation of 2MI. Experimental studies on the effect of the order of mixing of initial reagents on the 2MI yield confirmed the quantum-chemically substantiated favorable pathway for the formation of 2MI during the interaction of amine intermediates, and also revealed that the selectivity of the 2MI formation is achieved by successive mixing of acetaldehyde with ammonia until the formation of hydroxyamine products and their further interaction with glyoxal.