Cyanosilylation of α-butylthioacrolein

Cyanosilylation of α-butylthioacrolein with trimethylsilyl cyanide occurs as 1,2-addition. Concurrent rapid dimerization of α-butylthioacrolein occurred both in the presence and in the absence of H₂PtCl₆·6H₂O as a catalyst to give 2,5-dibutylthio-2,3-dihydro-4H-pyran-2-carbaldehyde, whose cyanosilylation afforded the corresponding cyanohydrin. The latter is prone to retrodiene degradation upon heating. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1418–1420, July, 1998.     

Asymmetric synthesis of α-substituted alkylphosphonates based on symmetrical dialkyl phosphites

Chiral C₂-symmetrical dialkyl phosphites and C₃-symmetrical trialkyl phosphites, derived from (−)-borneol, (−)-menthol, and 1,2∶5,6-di-O-isopropylidene-α-d-glucofuranose, were studied as the starting reagents for the preparation of chiral organophosphorus compounds. The reactions of C₂-symmetrical dialkyl phosphites and C₃-symmetrical trialkyl phosphites with aldehydes and amines or aldehydes are accompanied by asymmetrical induction at the α-carbon atom to yield optically active α-aminoalkylphosphanates or α-hydroxyalkylphosphonates, respectively. The stereoselectivity of the reaction depends on the structure of the starting compounds and the reaction conditions. Translated fromIzvestiya Akademii, Nauk, Seriya Khimicheskaya, No. 8, pp. 1588–1593, August, 1999.     

Novel Process Applications Using PHI-TEC II Adiabatic Calorimeter

This paper presents several applications of the PHI-TEC II that are not commonly associated with adiabatic calorimeters but which have proved to be extremely valuable. These include simulation of a deep oil well for enhanced oil recovery, isothermal calorimetry of a semibatch reaction, catalyst research using flow through reactors (both plug flow and CSTR) with controlled feeds of high pressure liquid and gas.This revised version was published online in November 2005 with corrections to the Cover Date.     

Calorimetric investigation of the interaction in the LaNi2.5Co2.4 Mn0.1−H2 system

The interaction of hydrogen with LaNi_2.5Co_2.4Mn_0.1 was studied in a wide temperature range (308–393 K) using the technique of “calorimetric titration.” The shape of thep-C-T diagrams changes with temperature change. The values of enthalpy and entropy of hydrogenation of LaNi_2.5Co_2.4Mn_0.1 were obtained for the first time by direct calorimetric investigations andp-C-T measurements. The volume effects of the hydrogen absorption reaction are considered, and the LaNi_2.4Co_2.4Mn_0.1H_4.9 hydride is shown to retain the CaCu₅-type hexagonal structure. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 21–24, January, 1999.     

Thermodynamic study of axial coordination reaction of zinc porphyrin with metal Schiff base and imidazole complex

A thermodynamic study is reported for the coordination reaction of ZnT ( m-X)PP derivatives (X = NO2, Cl, OCH3, H or CH3) with various ligands L (L= imidazole (Im), 2-methylimidazole (MeIm), clotrimidazole (CIM), imidazole-4-carboxaldehyde (4-CHOIm), unsymmetrical tetradentate copper Schiff base, CuIm(p-Cl), CuIm(p-Br), and nickel Schiff base, NiIm(p-Cl)), in dichloromethane solvent. Conversion of the four-coordinated ZnT( m-X)PP to the five-coordinated species is followed and isosbestic behavior is exhibited in the region among 450 and 700 run. The reaction of a copper(Ⅱ) or nickel(Ⅱ) imidazolate Schiff base with ZnT(m-X)PP results in the formation of an imidazolate bridged heterobinuclear complex. The stoichiometric number is unity for all axial ligands. The equilibrium constants were determined using the β band of ZnT( m-X)-PP in the 293-308 K range by the method of Rose and Drago. It increases with decrease in temperature, and △H0 < 0, △S0 < 0. The stronger the nucleophilic ability of the axial     

A short synthesis of the β-amyloid (Aβ) aggregation inhibitor 3-p-Toluoyl-2-[4′-(3-diethylaminopropoxy)-phenyl]-benzofuran

A short and convenient synthesis of 3-p-toluoyl-2-[4′-(3-diethylaminopropoxy)-phenyl]-benzofuran, an inhibitor of the aggregation of β-amyloid, which is thought to be the underlying cause of Alzheimer's disease, is described.     

The Use of Adiabatic Calorimetry for the Process Analysis and Safety Evaluation in Free Radical Polymerization

Adiabatic calorimetry is a technique that has been introduced as an important approach to hazard evaluation of exothermically reactive systems. In this paper the free radical polymerization of methyl methacrylate (MMA) has been studied. One of the most important aspects of MMA polymerization is its exothermicity and autoaccelerating behaviour, these characteristics can generate the occurrence of a runaway reaction.In a runaway situation the reacting system is close to adiabatic behaviour because it is unable to eliminate the heat that is being generated. An even worse situation can be reproduced in the laboratory with the Phi-Tec pseudo-adiabatic calorimeter. Process design parameters that are usually calculated from thermodynamic data or using semiempirical rules, such as adiabatic temperature rise or maximum attainable pressure, can be directly determined.The existence of the ceiling temperature has been experimentally demonstrated.This revised version was published online in November 2005 with corrections to the Cover Date.     

Study of acid-base properties of a SiO2?AlPO4 (80∶20 W/W) catalyst

2-Methyl-3-butyn-2-ol (MBOH) transformation was used as a test reaction in order to determine the acid-base properties of a SiO₂/AlPO₄ (80∶20 w/w) catalyst. Experiments were carried out in a microcatalytic pulse reactor and in a continuous-flow reactorvia Temperature Programmed Surface Reactions-Mass Spectrometry (TPSR-MS). Results are compared to acid-base properties calculated by other instrumental techniques.     

The Crystal Structure of Hexamolybdenum Halide NaMo_6X_9C_（l4）（X＝Cl_n＋I_（1－n）） by Solid State Reaction

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