Stereospecific and regioselective catalytic epoxidation of alkenes by a novel ruthenium(II) complex under aerobic conditions

Epoxidation of alkenes by molecular oxygen is effected in high yields by catalysis of RuCl2(biox)2 using isobutyraldehyde as the co-reductant: the reaction is stereospecific and regioselective

Influence of Sustained Compressive Stress on Ultrasonic Pulse Velocity in Concrete

Objective of this study is to evaluate the effect of compressive stress over non destructive assessment of field concrete using ultrasonic pulse velocity (UPV). Influence of compressive stress on UPV for different concrete grades (M25, M30 & M40) tested at laboratory and at in-situ M40 reinforced concrete (RC) columns of 42m height of a high bay building is discussed. It is found that there is an increase in pulse velocity for concretes stressed around 5 Mpa, in addition to the growth in velocity due to curing period tested using cubes after 7, 14, and 28 days water curing. In the field study, pulse velocity versus computed stress due to the transmitted load during construction stages of the RC columns prove that  grow in velocity is significant with respect to acting stress, water to cement ratio and curing age. The results obtained from the study can be used as a reference for concrete ageing programs wherein pulse velocity based assessment is an important tool

Effect of Irradiation on Quality of Vacuum-Packed Spicy Beef Chops

To develop an alternative pasteurization process for the spicy beef jerky (SBJ), it was treated with irradiation doses of 0, 0.5, 1.5, 3, 4, 6, and 8 kGy and the sensory attributes, texture properties, drip loss, and the protein biological efficiency were studied. The results showed that lightness, drip loss, and off-odor of SBJ increased, while the hardness, chewiness, gumminess, color preference, and taste of SBJ decreased with the increase in irradiation dose. This tendency was obvious as the irradiation dose increased to 6 kGy and 8 kGy. The possible reason for these quality changes might be due to the free radicals produced by irradiation. This speculation is supported by the decrease of the content of capsanthin and the increase of the content of TBARS of SBJ with the increase in irradiation dose. The plate counts of treated SBJ indicated that 4 kGy was suitable for pasteurization of SBJ

Exploration of supercritical water gasification of biomass using batch reactor

Title from PDF of title page (University of Missouri--Columbia, viewed on May 24, 2012).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Thesis advisor: Dr. William JacobyIncludes bibliographical references."July 2011"[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The focus of this study is on gasification of a biomass in supercritical water. Vapor mass yield in a batch reactor after 20 minutes in a 700[degrees]C furnace in air and supercritical water for a wide variety of biomass samples showed that the supercritical water enhanced the gasification efficiency, as it participates as both a solvent and a reactant. The heat of combustion and the heat of gasification had good correlation with the oxidation state of the carbon atom in each biomass sample and proved that thermodynamic changes of state are functions of elemental composition (oxidation state of the carbon atom). The gasification efficiency did not correlate with the oxidation state, concluding that biomass gasification efficiencies are similar for all types of biomass. The temperature and residence time are important operating parameters for supercritical water gasification. The vapor yield, gas composition, the carbon and hydrogen balance of supercritical water gasification were functions of gasification temperature, residence time and biomass load (concentration). Nano particle coating of sawdust enhances the vapor yield of sawdust. Supercritical water gasification of biomass at different heating rates showed that the vapor yield was found to depend on the time of heating during the initial period and later the heating rate played the major role. Modeling of thermochemical reactions in a batch reactor was described and used to estimate reaction order and activation energy for supercritical water gasification of ethanol, butanol and algae

A highly beta-stereoselective catalytic epoxidation of Delta(5)-unsaturated steroids with a novel ruthenium(II) complex under aerobic conditions

Catalytic beta-stereoselective epoxidation of Delta(5)-unsaturated steroid derivatives has been effected by a novel ruthenium(II) bioxazoline complex under aerobic conditions. The reactions are regio- and stereoselective. The reaction conditions provide the corresponding 5 beta,6 beta-epoxides with high degree of stereoselectivity (88-96%) in very good yields, while oxidation of steroid derivatives with peracids leads to 5 alpha,6 alpha-epoxides as the major products. The overall conformation of the steroid nucleus is nearly planar in the cholesteryl ester, while it is bent at the junction between the rings A and B in the 5 beta,6 beta-epoxide. This change from pseudo trans- to cis-stereochemistry of the A-B ring junction provides more room for the catalyst to approach from the beta-face of the steroidal skeleton

Stereospecific and regioselective catalytic epoxidation of alkenes by a novel ruthenium(II) complex under aerobic conditions

Epoxidation of alkenes by molecular oxygen is effected in high yields by catalysis of RuCl2(biox)(2) using isobutyraldehyde as the co-reductant: the reaction is stereospecific and regioselective

Highly Enantioselective Synthesis of 2,3-Dihydroquinazolinones through Intramolecular Amidation of Imines

Enantioselective synthesis of 2,3-dihydroquinazolinones (DHQZs) was accomplished using readily available Sc(III)-<i>inda</i>-pybox as the catalyst. This is the first report on the metal catalyzed asymmetric intramolecular amidation of imines to synthesize DHQZs

Stereodivergent Synthesis of 3‑Aminooxindole Derivatives Containing Vicinal Tetrasubstituted Stereocenters via the Mannich Reaction

A highly enantioselective stereodivergent synthesis of 3-aminooxindole derivatives was accomplished via asymmetric Mannich reaction between 2-substituted benzofuran-3-one and isatin-derived ketimines. Both <i>anti</i> and <i>syn</i>-selective chiral 3,3-disubstituted amino oxindoles bearing two adjacent tetrasubstituted stereogenic centers with high yield and excellent enantioselectivities were obtained using readily available cinchona-alkaloid derived organocatalysts. The control experiment revealed that oxygen atom present in the benzofuran ring played an important role in switching diastereodivergence. The obtained Mannich product was further transformed into a biologically important 2,3-dihydrobenzofuran derivative having three contiguous stereocenters with no loss of enantioselectivity

Highly Enantioselective Synthesis of 2,3-Dihydroquinazolinones through Intramolecular Amidation of Imines

Enantioselective synthesis of 2,3-dihydroquinazolinones (DHQZs) was accomplished using readily available Sc(III)-<i>inda</i>-pybox as the catalyst. This is the first report on the metal catalyzed asymmetric intramolecular amidation of imines to synthesize DHQZs