Scrubbing Hydrogen Sulfide from Gases. A Rational Approach

Worsening of the environmental situation in many regions of Russia in recent decades is to a great degree due to production and refining of oil and gas with a high hydrogen sulfide content. Industrial methods of utilization of hydrogen sulfide are extremely irrational: it is either burned in flares or used for production of sulfur whose quality and quantity pose new problems related to its use.     

Physicochemical characteristics of polyethers prepared using double metal cyanide catalysts

Branched macromolecular polyethers (PEs) based on propylene and ethylene oxides are used as an active base for composites of demulsifiers of oil emulsions. In this work, features of the polymerization of propylene oxide in the presence of double metal cyanide catalysts are studied using the example of PE based on monoethylene glycol and glycerol by varying the molecular weight in the range of 6000–150000. Polymerization is performed in a laboratory reactor at 110–120°C and a catalyst concentration of 50 to 300 ppm. The viscosity, iodine value, and molecular weight characteristics of the PE samples are determined. It is shown that PEs with molecular weights of 6000–40000 have narrow molecular weight distributions (MWDs) and low concentrations of unsaturated impurities. A further increase in the molecular weight of PEs leads to the broadening of MWDs and a polydispersity value of 2.5–3.9, due to the formation of low-molecular weight unsaturated and bifunctional PEs. The results from this work can be employed to developing a process technology for PEs using double metal cyanide catalysts.     

Optimizing the Structure of a Production System for Activated Carbon

Russian Engineering Research - A system for the production of activated carbon is considered. The thermal deformation of its components in operation is of interest. A frame design is developed,...     

Kinetics of the reaction of propylene oxide with carbon dioxide in the presence of tetrasubstituted ammonium and phosphonium halogenides

Reactions of alkylene oxides with carbon dioxide underlie the industrial technology of ethylene- and propylene carbonates. Looking for new catalytic systems for these processes remains of interest due to the possibility of creating a new energy-saving process for the production of ethylene and propylene glycols. This work is aimed at comparing the catalytic activity of halogenides in the reaction of propylene oxide (PO) and carbon dioxide in the presence of tetrasubstituted ammonium and phosphonium halogenides, and evaluating the feasibility of using them in designing industrial technologies for the production of alkylene carbonates and glycols as active catalytic systems. Triphenylphosphine halogenides have been shown to possess high catalytic activity as compared to triethanolamine-based analogs. In terms of efficiency, triphenylphosphonium bromides are as good as the familiar catalysts based on potassium iodide. The high activity of these catalysts in the reaction for propylene carbonate (PC) production and their good solubility in the reaction medium allow us to propose them for the development of industrial technology for the subsequent production of alkyl carbonates and alkylene glycols.     

Mathematical model of solvent electrodesorption from capillary-porous materials under decreased pressure of the medium

A mathematical model of removal of adsorption-bound moisture from capillary-porous materials by decreasing the pressure in the presence of an internal heat source in the volume of the adsorbent is developed.     

Heat and mass transfer under the conditions of the external problem for processes occurring with a decrease in the pressure of the medium

A mathematical model of the heat and mass transfer in a multicomponent vapor-gas phase is developed for the case of ideal mixing of components with a decrease in the total pressure of the medium above the surface of a wet material or solution.     

Pd[tBuNH(S)NHP(O)(OiPr)2-S]2Cl2 Complex as Air- and Moisture-Stable Catalyst for Palladium Catalyzed Suzuki Cross-Coupling Reaction

A highly efficient Suzuki cross-coupling reaction between phenyl bromide and phenylboronic acid catalyzed by the palladium complex Pd[tBuNH(S)NHP(O)(OiPr)₂-S]₂Cl₂ in acetonitrile, toluene, THF or DMF has been investigated. The bases we have employed for this reaction were Na₂CO₃, K₂CO₃ or Cs₂CO₃. It was established that using DMF and K₂CO₃ at 100 °C shows excellent yields of the product at the catalyst amount of 0.1 mmol. The cross-coupling reactions of iodo- and chloro-benzene with phenylboronic acid were also investigated. The influence of the halide nature was as expected.