Dielectric Parameters and Hydrogen Bond Interaction Study of Binary Alcohol Mixtures

The formation of hydrogen bonds between different types of molecules in binary alcohol mixtures (methyl alcohol, ethyl alcohol, ethylene glycol, propylene glycol and glycerol) have been investigated (each system at 21 mixture concentrations) by an analysis of their dielectric parameters. The static dielectric constant ε _o, limiting high-frequency dielectric constant ε _∞, excess dielectric parameters ε _o^E and ε _∞^E, effective Kirkwood correlation factor g ^eff, and corrective Kirkwood correlation factor g _f of the binary alcohol mixtures were determined at 25 °C in order to explore hydrogen-bond interactions and the strength of molecular connectivities between unlike alcohol molecules and their dipole alignment. These results confirm that the different alcohol mixtures form hydrogen-bonded structures, which are strongly influenced by the numbers of hydroxyl groups and carbon atoms of the alcohol molecules and vary with the concentrations of the mixtures.     

Volumetric Properties of Aqueous Solutions of L-Glutamic Acid and Magnesium-L-Glutamate

Densities of aqueous solutions of L-glutamic acid and magnesium-L-glutamate were determined from T=288.15 to 333.15 K at 5 K temperature intervals. The measured densities were used to evaluate the apparent molar volumes, V _2,φ (m,T), the cubic expansion coefficients, α(m,T), and the changes of isobaric heat capacities with respect to pressure, (∂ C _p /∂ p) _T,m . They were qualitatively correlated with changes in the structure of water that occur when L-glutamic acid or magnesium-L-glutamate are present.     

Studies on the CMC and Thermodynamic Functions of a Cationic Surfactant in DMF/Long-Chain Alcohol Systems Using a Microcalorimetric Method

The power-time curves of the micelle formation process were determined at four temperatures for a cationic surfactant [cetyltrimethylammonium bromide (CTAB)] in a non-aqueous solvent [N,N-dimethylformamide (DMF)] by titration microcalorimetry. From the data of the minimum of the titration point and the area of the power-time curves, values of their CMC and ΔH _m ^θ were obtained. Values of ΔG _m ^θ and ΔS _m ^θ were also calculated according to standard thermodynamic relations. For the cationic surfactant CTAB, the relationships involving the carbon numbers of the alcohols, the alcohol’s concentration, and the temperature on the CMC, and also the thermodynamic functions for micellization are discussed. For systems containing an identical concentration of various alcohols, values of the CMC, ΔH _m ^θ and ΔS _m ^θ increased whereas those of ΔG _m ^θ decreased with increasing temperature. For systems containing identical alcohol concentrations at the same constant temperature, values of the CMC, ΔH _m ^θ ,ΔG _m ^θ and ΔS _m ^θ decreased with increasing carbon number of the alcohol. For systems containing the same alcohol at the same temperature, the CMC and ΔG _m ^θ values increased whereas ΔH _m ^θ and ΔS _m ^θ decreased with increasing alcohol concentration.     

“Solid Phase Synthesis of Cis-Coniferyl Alcohol”

Synthesis of cis-coniferyl alcohol (4-hydroxy-5-methoxy-cinnamyl alcohol), using support on Wang's resin is described.     

Synthesis of Cytotoxic Sinapyl Alcohol Derivatives fromLigularia nelumbifolia

Total synthesis of two cytotoxic natural products, nelumol A(1) and nelumal A(2), were carried out by two different paths. 4-O-Benzyl substitute analogues 26 and 27, as well as the 4-O-(2-methyl-butenyl) derivatives 29 and 30 were also synthesized for a SAR invesigation. 1 and 2 were also measured on different tumor cell line.     

Measurement of Magnesium Stability Constants of Biologically Relevant Ligands by Simultaneous Use of pH and Ion-Selective Electrodes

Simultaneous measurements with magnesium ion-selective and pH glass electrodes have been used for determination of the stability constants of magnesium ions with various biologically relevant ligands by alkalimetric titration under physiological conditions (37^○C, I=0.15 mol⋅dm⁻³). New systems were investigated: magnesium with pyroglutamate, pyridoxine and HEPES, along with citrate, lactate, glycinate, aspartate and glutamate. For comparison, calcium stability constants with the same ligands were determined similarly, using calcium ion-selective and pH glass electrodes. Ligand protonation constants, necessary for the calculation of the metal complex formation constants, were also determined.     

Synthesis of γ-Substituted Alcohol with Polymer-bound Amide

With solid phase organic synthesis method(SPOS), polymer-bound N-enoylprolinol(4) was prepared by the attachment of N-enoylprolinol(3) to Merrifield resin and was used for asymmetric Michael additions for the first time. The enantiomeric excess obtained by this method is increased as compared with that obtained by the corresponding solution phase reactions.     

Volumetric Study of Aqueous Solutions of Polyethylene Glycol as a Function of the Polymer Molar Mass in the Temperature Range 283.15 to 313.15 K and 0.1 MPa

Density measurements were made for binary aqueous solutions of polyethylene glycol at seven temperatures: 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15 K. Polyethylene glycol samples with nominal average molar masses of 3000 g⋅mol⁻¹ (PEG 3000), 6000 g⋅mol⁻¹ (PEG 6000), 10000 g⋅mol⁻¹ (PEG 10000) and 20000 g⋅mol⁻¹ (PEG 20000) were used. These results were used to determine the specific volumes of solutions with solute-to-solvent mass ratios (mass of the solute/mass of the solvent) in the range 0.0546 to 1.4932 for PEG 3000, from 0.0553 to 1.4986 for PEG 6000, from 0.0552 to 1.2241 for PEG 10000, and from 0.0530 to 1.2264 for PEG 20000. The differences between the specific volume of a solution and the specific volume of the pure solvent, at a given temperature, were represented by a virial-type equation in terms of solute concentration. The first-order coefficient of the expansion is the partial specific volume of the solute at infinite dilution. The higher-order coefficients are related to the contribution of pairs, triplets, and higher-order solute aggregates, according to the Constant-Pressure Solution Theory. The functional dependence of the virial coefficients upon temperature is discussed in terms of solute-solute and solute-solvent interactions. The effect of the PEG molar mass on the partial specific volume of solute at infinite dilution, as well as the contributions of pairs of solute molecules to the solution volume, are also investigated. The apparent specific volume, apparent specific expansibility, apparent specific expansibility at infinite dilution and virial coefficients of the apparent specific expansibility are also presented.     

Temperature Dependence of Physical Properties of Imidazolium Based Ionic Liquids: Internal Pressure and Molar Refraction

Density, speed of sound and refractive index of the imidazolium-based ionic liquids (ILs), 1-methyl-3-octylimidazolium chloride [C₈mim][Cl], 1-butyl-3-methylimidazolium methyl sulfate [C₄mim][C₁OSO₃], and 1-butyl-3-methylimidazolium octyl sulfate [C₄mim][C₈OSO₃], have been measured in the temperature range from 283.15 to 343.15 K. Experimental density and speed of sound have been used to calculate the internal pressure p _i of the ILs. The p _i values were found to be higher than those of water and molecular organic liquids, but lower than those of classical molten salts. We also calculated molar refraction R _M from the measured refractive index n _D in the temperature range from 288.15 to 343.15 K. Refractive indices of ILs were also higher than those of normal organic liquids, but comparable to long-chain hydrocarbon organic solvents. The structure-property correlation of the ILs has been discussed and the results have been compared to our earlier studies (Kumar in J. Solution Chem. 37:203–214, 2008).     

Synthesis of a New Chiral Cyclicβ-Amino Alcohol

The enantioselective chiral l,3,2-oxazaborolidine-catalyzed reduction of prochiralketones by borane has been intensively investigated'-'. Most oxazaborolidine catalystshave been prepared from chiral D-amino alcohols. In our previous study on the catalyststructure-enantioselectivity relationships, we prepared (R)-2-amino-1,l-diphenyl-3~(2naphthyl)-l-propanol I which proved to be a good precursor of chiral catalyst for theenantioselective borane reduction of prochiral ketones4-9. This let'ter d…     

Effect of Ionic Liquids on Catalytic Characteristics of Horse Liver Alcohol Dehydrogenase

The catalytic characteristics of horse liver alcohol dehydrogenase （HLADH） in the systems involving ionic liquids （ILs） （BMIm·Cl, BMIm·Br, BMIm·PF6, BMIm·BF4 BMIm·OTf and EMIm·Cl） were examined. HLADH displayed higher oxidation activity towards ethanol in the systems containing BMIm·Cl, BMIm·Br, EMIm·Cl or BMIm·PF6 with proper content than that in the IL-free buffer. An excessive amount of these ILs in the reaction systems resulted in an obvious decline in enzymatic activity. BMIm·BF4 and BMIm·OTf of any content investigated could considerably inhibit the enzyme. The anions of ILs showed significant effect on the activity, kinetic parameters and activation energy of HLADH-mediated ethanol oxidation. Additionally, BMIm·Cl, BMIm·Br, EMIm·Cl and BMIm·PF6 boosted markedly the thermostability of HLADH, while the enzyme was less thermostable in BMIm·BF4 or BMIm·OTf-containing systems. The associated conformational changes in HLADH caused by ILs were examined by UV technique.     

Adsorption properties of BEA zeolites and their aluminum phosphate extrudates for purification of isomaltose

The disaccharide isomaltose is produced via an enzymatic reaction and is adsorbed to BEA zeolite. This reaction integrated adsorption can be achieved as fluidized bed as well as fixed bed. We investigated isotherms, adsorption enthalpies and sorption kinetics of BEA zeolite and extrudates with a novel aluminum phosphate sintermatrix. These extrudates contain 50% (w/w) of BEA 150 zeolites (Si/Al = 75) as primary crystals. BET-surface for extrudates is 245 m²⋅g⁻¹ and 487 m²⋅g⁻¹ for zeolite. Extrudates show a monomodal macropore structure with a maximum at 90 nm. All isotherms show a type I shape. For lower equilibrium concentrations, which occur during the enzymatic reaction, Henry’s law is applied and compared to a Langmuir model. Adsorption equilibrium constant K _i,L calculated from Langmuir for extrudates at 4 °C is 64.7 mL⋅g⁻¹ and more than twice as high as obtained from Henry’s law with K _i is 26.8 mL⋅g⁻¹. Adsorption on extrudates at 4 °C is much stronger than on zeolite crystals where the Henry coefficient K _i is 17.1 mL⋅g⁻¹. Adsorption enthalpy Δh _Ad calculated from van’t Hoff plot with the Henry equation is −44.3 kJ⋅mol⁻¹ for extrudates and −29.6 kJ⋅mol⁻¹ for zeolite crystals. Finally, the kinetics for ad- and desorption were calculated from the initial slope. The diffusion rate for ad- and desorption on extrudates were in the same range while adsorption on zeolites is three orders of magnitudes faster than desorption.     

Synthesis Characterization and Viscosity Studies of Homopolymer of Methyl Methacrylate and Copolymer of Methyl Methacrylate and Styrene

A homopolymer of methyl methacrylate (MMA) and its copolymer with styrene at different compositions were synthesized and characterized. Viscosity measurements of the synthesized homopolymer and the copolymers in toluene solutions were performed at 313 K. Different equations were used to calculate the intrinsic viscosity, viscometric constants values, and molecular weight of the synthesized polymers. The values of intrinsic viscosity and viscosity average molecular weight obtained by the two methods (single point determination and graphical extrapolation) were compared in order to verify the validity of the single point determination for the polymers. Viscometric properties derived included the specific viscosity (it determines the contribution of the solute to the viscosity of the solution), the reduced viscosity (that provides a measure of the polymer capacity for increasing the solution viscosity), and the intrinsic viscosity.     

Dynamics of monolayer films formed on a substrate of square symmetry

The paper discusses the ground state properties and dynamics of monolayer films formed by atomic adsorbates on a square lattice, being the (100) plane of a face centered cubic crystal. The vibrations of films ordered into the commensurate c(2×2) as well as into the recently discovered ordered phase exhibiting a distorted Archimedean tiling of the type (3².4.3.4) are considered. The dispersion relations and the densities of states are determined and discussed.     

Studies of Partial Molar Volumes of Alkylamines in Non-electrolyte Solvents. IV. Alkyl Amines in Cyclic Ethers at 303.15 K

Apparent molar volumes V _φ,B of n-propylamine, n-butylamine, di-n-propylamine, di-n-butylamine, triethylamine, tri-n-propylamine, and tri-n-butylamine in 1,4-dioxane and in oxolane (tetrahydrofuran) have been determined at 303.15 K using a high-precision Anton Paar vibrating-tube densimeter (model DMA 60/602). The limiting partial molar volumes and limiting excess partial molar volumes are analyzed and interpreted in terms of solute-solvent interactions and structural effects of the molecules. Analyses were made of the contributions of specific interactions to the partial molar volumes of these primary, secondary and tertiary amines in 1,4-dioxane and oxolane using the Terasawa model, scaled particle theory (SPT) and hard-sphere theory (HST). The ERAS model has also been applied to estimate the apparent molar volumes and excess apparent molar volumes of alkylamine solutions in 1,4-dioxane and oxolane.     

The Enthalpies of Solution of L-cysteine, L-serine and L-asparagine in Aqueous Solutions of Some Alcohols at 298.15 K

Heats of solution, Δ_sol H _m , of L-cysteine, L-serine and L-asparagine amino acids have been measured at different concentrations of aqueous ethanol, propanol and 2-propanol at 298.15 K using solvation calorimetry. These data are compared with the results reported earlier for L-alanine in ethanol. The enthalpic coefficients, h _xy , of the solute-organic cosolvent pair interaction in water have been obtained from the McMillan-Mayer approach and the data have been interpreted in terms of various interactions and changes in solvent structure.     

Influence of Europium speciation on its accumulation in Brassica napus and over-expressing BnTR1 lines

This study aimed at influence of europium speciation on its accumulation in Brassica napus (CK) and over-expressing BnTR1 lines (OE), and the kinetics of Eu uptake were investigated. These results indicated that the uptake in the roots of OE was higher than that of CK at high concentrations of europium and even the enrichment in the roots of OE was as high as 20,000 mg/kg at 328.9 μΜ Eu, this suggested that OE might have better resistance to uranium than CK. The time kinetics in plants showed that there had the similar trend between CK and OE. The formation of Eu³⁺at pH 5 in deionized water was beneficial to plants enrichment Eu and carbonate could reduce the adsorption of Eu in two group and phosphate almost completely impress the adsorption of Eu in two group, but citric acid could enhance europium root-to-shoot translocation in two group. These results would help understanding the mechanism of Eu uptake in Brassica napus (CK) and over-expressing BnTR1 lines (OE), therefore properly developing efficient europium/americium phytoremediation.     

Synthetic Studies of Et-743, Preparation of A Racemic Amino Alcohol Precursor

A mild two-step method was used to cleave the lactam ring of the tricyclic intermediate 1. A key racemic amino alcohol precursor 5 for the construction of Et-743 skeleton was synthesized from 1 through four steps in total yield of 47%.     

Synthesis of Chiral Sulfamide–Amine Alcohol Ligands for Enantioselective Alkylation of Aldehydes

A series of chiral sulfamide–amine alcohols (SAA) (1–6) has been easily synthesized from commercially available chiral amino alcohols. In the absence of Ti(O ⁱ Pr)₄, ligand 4 catalyzed the asymmetric addition of diethylzinc to aromatic aldehydes with moderate to good yields and enantioselectivities.