Optimization of the process of the allyl 1,3,4-trimethylcyclohex-3-en-1-carboxylate production by the full factorial experiment

Based on experimental studies and mathematical modeling method, the effectiveness of technological process for the production of allyl 1,3,4-trimethylcyclohex-3-en-1-carboxylate was forecasted. The optimal conditions of the process were revealed.     

Friedel-Crafts Synthesis of New Porous Aromatic Frameworks for Stabilizing Gas Transport Properties of Highly Permeable Glassy Polymers

Porous aromatic frameworks of new generation, PAF-FC, were prepared by the Friedel-Crafts reaction between tetraphenylmethane and dimethoxymethane and were characterized. The material obtained has the structure similar to that of PAF-11 and exhibits high porosity (S_BET = 768 m² g^?1). Introduction of 10 wt % PAF-FC allows stabilization of the gas transport characteristics of poly[1-trimethylsilyl–1-propyne] (PTMSP) in time. For example, after 500-h annealing at 100°C, the CO₂ permeability coefficient of the PTMSP/PAF-FC composite decreased by 15%, whereas the ideal CO₂/N₂ selectivity increased from 5.6 to 6.1. The resultant gas transport characteristics appeared to be comparable to those of the previously studied porous aromatic frameworks PAF-11. It should be noted that synthesis of PAF–11 requires using expensive chemicals in large amounts, whereas PAF-FC synthesis by linking of aromatic fragments of monomeric monomers using the Friedel-Crafts reaction is much simpler and involves the use of considerably less expensive chemicals.

     

Synthesis and properties of brominated poly(1-trimethylsilyl-1-propyne)

Russian Chemical Bulletin - A procedure of selective bromination of poly(1-trimethylsilyl-1-propyne) using N-bromosuccinimide as the brominating agent was developed. This method allows to obtain...     

Optimization of synthesis conditions of 2,3-dimethylbutadiene

Catalytic dehydration of anhydrous 2,3-dimethyl-2,3-butanediol and 2,3-dimethyl-2,3-butanediol hexahydrate under atmospheric pressure was studied. Effect of temperature and reagent flow rate on the yield of 2,3-dimethylbutadiene was examined. The optimal conditions of these processes were found.     

Effect of the reactants molar ratio on the kinetics of cycloaddition of 2,3-dimethylbuta-1,3-diene to allyl methacrylate

The cycloaddition reaction between 2,3-dimethylbuta-1,3-diene and allyl methacrylate proceeds by the second order kinetics. The rate constants increase with the increase in the excess of one of the reactants. The change in the effective rate constants is described by the Michaelis-Menten equation indicating that the reaction proceeds through the initial equilibrium stage of formation of an intermediate complex which then transforms into the product. The effective rate constants, the equilibrium constants of formation of the intermediate complex, and the rate constant of its transformation into the reaction product were determined, as well as the thermodynamic parameters of the formation of the intermediate complex and the activation parameters of the transformation of the intermediate complex into the product. The limiting stage of the reaction is established and its mechanism is suggested.     

Algorithm for code formation in cutaneous analyzer periphery

Integrative methods for the analysis of afferent activity (colliding flows, discrimination of signal against noise, and cross-correlation functions) are used to quantify the characteristics of impulse flows and determine the differences between them under proportioned mechanical, temperature, and painful stimuli of cutaneous receptors and nerves. It is shown experimentally that the code of sensory signals produced in response to stimuli of different modalities is a space-time impulse distribution, i.e., a flow structure (pattern). Tests of the sensations experienced by human volunteers under simultaneous impacts of specific patterns on the central nervous system are performed. The mechanism of thermal sensory code formation is examined.Nizhny Novgorod Medical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 9, pp. 1148–1555, September, 1994.     

Synthesis of 1,3,4-trimethylcyclohex-3-en-1-carboxylic acid allyl ester

The process of diene cyclization of 2,3-dimethylbutadiene with allyl methacrylicate was investigated. Effects of temperature, reaction duration, and ratio of reagents on the yield of 1,3,4-trimethylcyclohex-3-en-1-carboxylic acid allyl ester was studied. Optimal conditions of passing the process were found.     

Modification of Poly(4-Methyl-2-Pentyne) in Supercritical Fluid Medium for Production of CO<Subscript>2</Subscript>-Selective Gas-Separation Membranes

The work is devoted to exploring the possibility of using supercritical fluids as media for modification of polymers offering promise for production of gas-separation membranes with the goal to improve selectivity towards CO₂. The possibility is demonstrated for introduction of fragments of quaternary ammonium salts into the structure of poly(4-methyl-2-pentyne) with the help of a two-stage process: bromination of the initial polymer with N-bromosuccinimide followed by the addition of the tertiary amine—N-butylimidazol— conducted in supercritical fluids as a medium. The use of trifluoromethane as the reaction medium provides the highest degree of modification of the brominated polymer with the amine. The polymer produced under the optimized conditions demonstrates a threefold increase of the calculated selectivity of separation of CO₂ and N₂ in comparison with the initial poly(4-methyl-2-pentyne).