Intermolecular Photocatalytic Chemo‐, Stereo‐ and Regioselective Thiol–Yne–Ene Coupling Reaction

The first example of an intermolecular thiol–yne–ene coupling reaction is reported for the one-pot construction of C−S and C−C bonds. Thiol–yne–ene coupling opens a new dimension in building molecular complexity to access densely functionalized products. The employment of Eosin Y/DBU/MeOH photocatalytic system suppresses hydrogen atom transfer (HAT) and associative reductant upconversion (via C−S three-electron σ-bond formation). Investigation of the reaction mechanism by combining online ESI-UHRMS, EPR spectroscopy, isotope labeling, determination of quantum yield, cyclic voltammetry, Stern–Volmer measurements and computational modeling revealed a unique photoredox cycle with four radical-involving stages. As a result, previously unavailable products of the thiol–yne–ene reaction were obtained in good yields with high selectivity. They can serve as stable precursors for synthesizing synthetically demanding activated 1,3-dienes

ТЕХНОЛОГИЧЕСКИЕ РЕЖИМЫ ПОЛУЧЕНИЯ УКСУСА ИЗ ПИВНЫХ ДИАЛИЗАТОВ

This article is devoted to the development of technological regimes for the rational use of beer dialysates formed in the production of non-alcoholic beer. One of the effective ways to use it, is the production of vinegar. The article presents data on the study of volatile components, organic acids and amino acids of initial beer dialysates with a volume fraction of ethyl alcohol of 0.6 % and brewing dialysates concentrated to a volume fraction of ethyl alcohol of 5.0 % and 8.0 %. The data of the study of volatile components, organic acids and amino acids of vinegar obtained as a result of biochemical oxidation of concentrated brewing dialysates with acetic acid bacteria are presented. The oxidation process was carried out by a periodic deep-seated method. Influence of aeration regimes and initial concentration of acetic acid on the functional activity of acetic acid bacteria in obtaining vinegar from beer dialysates is shown. Recommended technological regimes for obtaining vinegar in a periodic deep method from beer dialysates.Данная статья посвящена разработке технологических режимов рационального использования пивных диализатов, образующихся при производстве безалкогольного пива. Одним из эффективных способов его применения является производство уксуса. В статье приведены данные исследования летучих компонентов, органических кислот и аминокислот исходных пивных диализатов с объемной долей этилового спирта 0,6% и пивных диализатов, сконцентрированных до объемной доли этилового спирта 5,0% и 8,0%. Приведены данные исследования летучих компонентов, органических кислот и аминокислот уксуса, полученного в результате биохимического окисления сконцентрированных пивных диализатов уксуснокислыми бактериями. Процесс окисления проводился периодическим глубинным способом. Показано влияние режимов аэрации и стартовой концентрации уксусной кислоты на функциональную активность уксуснокислых бактерий при получении уксуса из пивных диализатов. Рекомендованы технологические режимы для получения уксуса периодическим глубинным способом из пивных диализатов

The Numerical Simulation of Shallow Water: Estimation of the Roughness Coefficient on the Flood Stage

The results of the numerical simulations of the dynamics of shallow waters for Volga-Akhtuba Floodplain are discussed. The mathematical model is based on the system of Saint-Venant equations. Numerical solution applies a combined Lagrangian-Eulerian (cSPH-TVD) algorithm. We have investigated the features of the spring flood in 2011 and found the inapplicability of the hydrodynamical model with the constant roughness coefficient n M . We have found a good agreement between the results of numerical simulations and the observational data at gauging stations which allows us to estimate n M in low water n M min = 0.02 and the maximum water level in the river Volga n M max = 0.06–0.07

Reversible Radical Addition Guides Selective Photocatalytic Intermolecular Thiol-Yne-Ene Molecular Assembly

In the realm of modern organic chemistry, harnessing the power of multicomponent radical reactions presents both significant challenges and extraordinary potential. This article delves into this scientific frontier by addressing the critical issue of controlling selectivity in such complex processes. We introduce a novel approach that revolves around the reversible addition of thiyl radicals to multiple bonds, reshaping the landscape of multicomponent radical reactions. The key to selectivity lies in the intricate interplay between reversibility and the energy landscapes governing C-C bond formation in thiol-yne-ene reactions. The developed approach not only allows to prioritize the thiol-yne-ene cascade, dominating over alternative reactions, but also extends the scope of coupling products obtained from alkenes and alkynes of various structures and electron density distributions, regardless of their relative polarity difference, opening doors to more versatile synthetic possibilities. In the present study, we provide a powerful tool for atom-economical C-S and C-C bond formation, paving the way for the efficient synthesis of complex molecules. Carrying out our experimental and computational studies, we elucidated the fundamental mechanisms underlying radical cascades, a knowledge that can be broadly applied in the field of organic chemistry

CCIM Technology for Treatment of LILW and HLW -10209

ABSTRACT Cold Crucible Inductive Melting (CCIM) technology is developed and applied at SIA Radon for vitrification of low-and intermediate-level radioactive wastes (LILW). During last eight years SIA Radon researchers were dealing with application of CCIM for vitrification of high level wastes (HLW). HLW surrogates of Savannah River Site (SRS), USA, and Production Association (PA) "Mayak", Russia, were vitrified and products were examined in details. CCIM operational conditions and process variables (feed rate, melt rate, melting ratio, etc.) were determined. Feasibility of vitrification of HLW with high aluminum and iron contents has been proven. Various types of pumps to feed slurries into the crucible were tested. Maximum waste loading in glass keeping its high chemical durability was determined. The heat balance in the system "high frequency generator -crucible" was summarized and effective power spent for batch melting and melt homogenization was measured. Since 2007 design and construction works on cold crucible for HLW treatment were carried out. Previous experience in cold crucible design and operation experience during vitrification of actual LILW and HLW surrogates were applied. Principles of operation and control of the inductive melter were formulated. Automated control system has been designed and a set of the equipment required has been completed. The new cold crucible with the automated control system and auxiliary equipment is recommended for implementation at PA "Mayak" for study of HLW vitrification process of both spent nuclear fuel (SNF) reprocessing and old ("historical") tanks with variable chemical composition

The Lightcurve Of 4179-Toutatis - Evidence For Complex Rotation

The Apollo asteroid 4179 Toutatis passed within 0.0242 AU of Earth in December 1992, and photometry was obtained by observers from at least 25 sites around the world, at solar phase angles between 121 degrees and 0.2 degrees. The phase curve is well described in the H, G system with a mean H of 15.3 and a slope parameter G of 0.10 +/- 0.10. However, the rotational lightcurve is very unusual. The amplitude is large (1.2 magnitudes) and the rotation period is extremely long (several days). Most remarkably, the lightcurve does not appear to be periodic: it is unlikely that a single rotation period can account for the lightcurve even when the rapidly changing viewing and illumination geometry during the close Earth approach is taken into account, though strong lightcurve minima recurred approximately every 7.3 days. The likely explanation is that Toutatis has complex, tumbling, rotation with a characteristic period between 3 and 7 days. As noted by A. W. Harris (1994 Icarus 107, 209-211), the damping time scale from complex to simple rotation for a small, slowly rotating asteroid like Toutatis is so long that complex rotation is expected, but Toutatis is the first asteroid to show such strong observational evidence for complex rotation