Chemistry of the Gasification of Carbonaceous Raw Material

The paper represents the studies of the process of carbonaceous raw material gasification. The initial material is represented by bituminous coal of grade H with the carbon (C) content of 79.2-85.3 %. Experimental studies have been used to substantiate the parameters of combustible generator gases (СО, Н2, СН4) output depending on the temperature of a reduction zone of the reaction channel and gas flow velocity along its length. It has been identified that the volume of the raw material input to be used for gasification process changes in direct proportion depending on the amount of burnt-out carbon and blow velocity. The gasification is intensified in terms of equal concentration of oxygen and carbon in the reaction channel of an underground gas generator. The gasification rate is stipulated by the intensity of chemical reactions, which depend immediately on the modes of blow mixture supply. Moreover, they depend directly on the intensity of oxygen supply to the coal mass and removal of the gasification products.

Reactive pathways toward parasitic release of singlet oxygen in metal-air batteries

The superoxide disproportionation reaction is a key step in the chemistry of aprotic metal oxygen batteries that controls the peroxide formation upon discharge and opens the way for singlet oxygen release. Here we clarify the energy landscape of the disproportionation of superoxide in aprotic media catalyzed by group 1A cations. Our analysis is based on ab initio multireference computational methods and unveils the competition between the expected reactive path leading to peroxide and an unexpected reaction channel that involves the reduction of the alkaline ion. Both channels lead to the release of triplet and singlet O2. The existence of this reduction channel not only facilitates singlet oxygen release but leads to a reactive neutral solvated species that can onset parasitic chemistries due to their well-known reducing properties. Overall, we show that the application of moderate overpotentials makes both these channels accessible in aprotic batteries.

Mechanisms of 14C(11B,10B)15C reaction at energy 45 МеV for ground and excited states of 10B and 15C nuclei

New experimental data for differential cross-sections of the reaction 14C(11B,10B)15C at Еlab(11B) = 45 MeV were obtained for transitions to the ground and excited states of the exit reaction channel nuclei. The experimental data were analyzed within the coupled-reaction-channels method (CRC). The 14C + 11B elastic scattering channel as well as channels for one- and two-step transfers of nucleons and clusters were included in the coupling scheme. The Woods - Saxon (WS) potential was used in the CRC-calculations for the entrance reaction channel with the parameters deduced previously from the analysis of the experimental data of 11B + 14C elastic and inelastic scattering, whereas the WS potential for the exit 15C + 10B reaction channel was deduced from the fit of CRC cross-sections to the 14C(11B,10B)15C reaction experimental data. Needed for CRC-calculations spectroscopic amplitudes (factors) of the nucleons and clusters transferred in the reaction were calculated within the translational-invariant shell model. The mechanisms for one- and two-step transfers of nucleons and clusters were investigated in this reaction. The 15C + 10B potential parameters were deduced, and comparisons of the CRC reaction cross-sections calculated with the 15C + 10B and 12,13C + 10B potential parameters were performed. The differences between these CRC calculations were observed, e.g. "isotopic effects" were observed for the potentials of 10B interaction with 12,13,15C carbon isotopes.