Enzymatic hydrolysis of lignocellulosic materials in aqueous media and the subsequent microbiological synthesis of bioethanol

The enzymatic hydrolysis of lignocellulosic materials (LCMs) from miscanthus and oat husks (OH) in an aqueous medium and the subsequent production of ethanol are studied. LCMs are obtained at a pilot plant of the Institute of Problems of Chemical and Energy Technologies by means of one-stage nitric acid treatment. Enzymatic hydrolysis is conducted in an aqueous medium with a high initial concentration of phosphates (90 g/L) using freely available CelloLux-A and BrewZyme BGX industrial enzymatic preparations. The yields of reducing compounds are found to be 65.4 and 73.3% for miscanthus and oat husk LCM, respectively. The composition of monosaccharides (products of enzymatic LCM destruction) is studied for the first time. It is shown that glucose comprises the largest share of monosaccharides. Ethanol is produced from LCM for the first time. Ethanol yields per metric ton of raw material are 19.4 and 16.2 daL/t for miscanthus biomass and OH, respectively. Ethanol samples are characterized by low methanol contents (0.002 to 0.005 vol %).     

The influences of the gas rate dissolution and mass-transfer limitation at the interfaces on selectivity of gas–liquid processes in stirred reactors with a suspended catalyst

A complex mathematical model accounting for the hydrogen dissolution process in suspensions and mass-transfer steps at the liquid–solid interface for the gas and liquid components is given. The calculated data according to the model for the reaction A→B→C shows, that the yield of an intermediate product B is very much affected by the relation of the gas component mass-transfer coefficient on the gas–liquid interface to that on the liquid–solid one. The hydrogenation of chlornitroaromatic compounds was analysed. The kinetics of the catalytic reduction of p-chlornitrobenzene to p-chloraniline via corresponding arylhydroxilamine on the Ir/C catalyst experimentally in a batch reactor has been studied. In this process the first reactions depend on the hydrogen concentration but the second ones are not dependent — this is a disproportion of the intermediate product to the final product — amine.     

Optical absorption and structure of energy bands of GdNi<Subscript>5 − x</Subscript>Cu<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> intermetallic compounds

Optical properties of intermetallic compounds GdNi_{5 ? x} Cu _x (x = 0, 0.5, 1, 1.5, and 2) have been studied in a spectral range from 0.22 to 15 μm using the ellipsometry method. The substitution of copper for nickel has been found to lead to local changes in the interband optical conductivity spectra. A new quantum-absorption band, whose intensity increases substantially with increasing copper content, has been found at 3–4 eV. The relaxation and plasma frequencies of conduction electrons, which were calculated using data on the optical parameters, also depend on the concentration. Self-consistent calculations of the electronic structure of the intermetallic binary GdNi₅ compound have been performed using the LSDA + U method. The density of electronic states for two spin projections and the frequency dependence of the interband optical conductivity of the compound have been calculated.