Man Singh

Thermodynamic studies of molar volume, pair and triplet interactions at increasing side chain length of α-amino acids in aqueous potassium chloride solutions at different concentration and 310.15 K

Abstract Densities ( ρ ) of glycine, alanine and leucine in aqueous solutions of potassium chloride (KCl) (0.01–0.10xa0mol kg −xa01 ) have been measured at 310.15xa0K. Apparent molar volumes ( V ϕ ), limiting partial molar volumes ( V ϕ 0 ) and group contributions to partial molar volumes have been determined for the amino acids. The trends of transfer volumes (Δ V ϕ 0 ) have been interpreted in terms of solute–cosolute interactions on the basis of a cosphere overlap model. Pair and triplet interaction coefficients have also been calculated from transfer parameters.

Study of apparent molal volume and viscosity of mutual citric acid and disodium hydrogen orthophosphate aqueous systems

Fundamental properties, density (ρ) and viscosity (η), of citric acid (CA) and disodium hydrogen orthophosphate (DSP) at various strengths were obtained at different temperatures. The ρ and η values were used to determine apparent molal volumes and viscosity of systems. The ρ, VΦ and η values were regressed against molalitym for ρ0, η0 and VΦ0, the limiting constants at infinite dilution (m → 0) for ionic and molecular interactions. The ρ0 and VΦ0 of aq. acids are higher than those of aq. DSP and the viscosity of DSP is higher than that of aq. CA. Examination of ρ0 and VΦ0 functions indicates that mutual compositions of CA and DSP counterbalance concentration and temperature effects on pH in bioprocesses.

Applications of activation energy and transition state theory for nucleos(t)ides and furanose helix puckering interactions in aqueous medium from 288.15 to 298.15 K

Density ρ/103u2009kgu2009m−3, viscosity η/10−1u2009kgu2009m−1u2009s−1 and surface tension γ/Nu2009m−1 of nucleosides (2-deoxy adenosine (DOA), thymidine (TMD)), nucleotides (guanosine monophosphate (GMP), adenosine triphosphate (ATP)) and their integral furanose sugar, 2-deoxy ribose (DOR) solutions have been measured at three different temperatures. The ρ values were used for apparent molal volume (V χ /10−6u2009m3u2009mol−1), η and γ calculations; η fitted in extended Jones–Dole equation for B/kgu2009mol−1 and D/(kgu2009mol−1)2 coefficients. The γ and V χ were regressed against molality, m for limiting surface tension, γ0 and apparent molal volume, at mu2009→u20090. Partial molal volume ( ) of water calculated from ρ values. Free energy of activation of viscous flow ( /kJu2009mol−1) per mol of solvent was calculated from η0 and and of solution from B and , and of dropwise flow of biomolecules from γ0 and values. The and depict a state of activation energy for structure making and breaking of solvent. The B and γ0 values are used to calculate transition state functions, − and u2009≥u20090 oru2009≤u20090 for critical state molecular optimization to explain positive transitions of interacting heteromolecules. The , and are found to be negative inferring biomolecules as water structure breakers.

SURVISMETER, 2-IN-1 FOR VISCOSITY AND SURFACE TENSION MEASUREMENT, AN EXCELLENT INVENTION FOR INDUSTRIAL PROLIFERATION OF SURFACE FORCES IN LIQUIDS

Viscosities (η, N s m-2) and surface tensions (γ, N m-1) of methanol, ethanol, glycerol, ethyl acetate, n-hexane, diethyl ether, chloroform, benzene, carbon tetrachloride (CCl4), tetrahydrofuran (THF), dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetonitrile, and formic acid have been measured with survismeter and compared with the data obtained by Ubbehold viscometer and stalagmometer, respectively. The ±1.1 × 10-5 N s m-2 and ±1.3 × 10-6 N m-1 deviations are noted in the data, in fact literature data of surface tension and viscosity are available to 2nd and 3rd place of decimals, respectively, while the survismeter measures them to 3rd and 4th place of decimals, respectively. The survismeter is 2-in-1 for viscosity and surface tension measurements together with high accuracies several times better than those of the separately measured data. Viscosities and surface tensions of aqueous DMSO, THF, DMF, and acetonitrile from 0.01 to 0.20 mol kg-1 and mannitol from 0.005 to 0.02 mol kg-1 have been measured with survismeter with ±1.2 × 10-5 N s m-2 and ±1.3 × 10-6 N m-1 deviations, respectively. The data are used for friccohesity and dipole moment determination, the lower viscosities, surface tension, and friccohesity values are noted for mannitol as compared to DMSO, THF, DMF, and acetonitrile solutions. The weaker molecular interactions are noted for mannitol. As compared to viscometer and stalagmometer individually, it is inexpensive and minimizes 2/3rd of consumables, human efforts, and infrastructure with 10 times better accuracies.

Surface tension and viscosity measurements of liquids with the survismeter: a single instrumental unit

Surface tension (γ) and viscosity (η) data of aqueous solutions of the deoxyadenosine (DOA) and the deoxyribose (DOR) sugars have been measured with the survismeter, a new instrument, along with tetrahydrofuran (THF), dimethylformamide (DMF), acetonitrile and dimethylsulphoxide (DMSO) solvents. The same properties have also been measured with a stalagmometer and a viscosimeter, respectively, which afford the same information, albeit at the expense of a larger amount of chemicals and solvents. We obtain comparatively better accuracy in both kinds of measurements than with conventional methods. Therefore, the survismeter lends itself as a simple and reliable instrument.

Synthesis and Spectroscopic Study of Praseodymium(III) Complexes with Di-Substituted Heterocyclic Compound : N,N-di Hydroxybenzalethylene(Sal2en)

Praseodymium(III) complexes with Sal2en (N,N‐di hydroxybenzalethyene) as ligand in 1∶2 and 1∶3 ratios were synthesized in alcoholic medium with Praseodymium nitrate as template agents. The complexes were characterized with IR, H1NMR and thermogravimetrical analysis (TGA), differential thermogravimetrical analysis (DTA) and differential scanning calorimetery (DSC). A 1282.75 cm−1 stretching frequency in IR spectra infer linkage of Pr(III) through nitrogen of Sal2en, where Sal2en behaves as bidentate ligand. The [octaaquobis (N,N‐di hydroxybenzalethylene) Praseodymium(III)] and [octaaquotris (N,N‐di hydroxybenzalethylene) Praseodymium(III)] are probable proposed structural formula of complexes. H1NMR spectra confirms a further coordinate bond formation with N atom of synthesized ligand Sal2en (N,N‐di hydroxybenzalethylene) completes coordination number of Praseodymium metal. Thermogravimetrically analysis inferred 1∶3 ratio complex compound slightly higher exothermic than of 1∶2.

LIQUID–LIQUID INTERFACE STUDY OF HYDROCARBONS, ALCOHOLS, AND CATIONIC SURFACTANTS WITH WATER

Molecular interaction dynamics at liquid–liquid interface (LLI), involved nondispersive solution as compared with the interaction in bulk phase. Thereby, interfacial tension (IFT, mN/m) of LLI for four saturated hydrocarbons, six alcohols, and three cationic surfactants are reported at 298.15 K. The pentane, hexane, heptane, octane hydrocarbons and pentanol, hexanol, heptanol, 1-octanol, 2-octanol, and 1-decanol alcohols were used and IFT data were compared with 4 mm kg-1 dodecyltrimethylammoniumbromide (DTAB), trimethylsulfoxoniumiodide (TMSOI), methyltrioctylammoniumchloride (MTOAC) surfactants studied in benzene–water LLI. The IFT data are noted as hydrocarbons > DTAB > TMSOI > alcohols > MTOAC. The hydrocarbons and alcohols decreased IFT within 16 to 49% and 87 to 92%, respectively, whereas the surfactants within 78.3 to 95.9%. The alcohols developed interaction similar to surfactants and are denoted as nonionic surfactants for making mixtures of low IFT with hydrophilic and hydrophobic interactions to the level of the surfactants. The pentanol and MTOAC caused similar decrease in IFT so the pentanol developed the hydrophilic and hydrophobic interactions of the strength of MTOAC. Comparatively, the hydrocarbons showed lower decrease but the octane showed 49% decrease in IFT. Thus, the hydrocarbon with longer alkyl chain and the alcohol with shorter behave as good surfactants. The hydrocarbons with inductive effect on sigma bond between carbon atoms in alkyl chain also weakened the IFT and influenced the hydrophobic interactions. The MTOAC with four octyl units reduced 96% IFT so inductive effects monitor LLI dynamics.

Synthesis, Structural, and Physicochemical Study of First- and Second-Generation Melamine-Based Dendrimers

Abstract First-tier (G1) 2,4,6-tridiethymalonate-triazine (2,4,6-TDEMTA) and second-tier (G2) 2,4,6-hexadiethylmalonate-triazine (2,4,6-HDEMTA) dendrimers were prepared with melamine (1,3,5-triazine) as core (G0) and sodium malonate ester for bifurcation of chains. The trichlorotriazine (TCT) and sodium diethyl malonate (SDEM) aqueous solutions were mixed, and a creamy white precipitate of G1 was obtained. The G1 was hydrolyzed in alkaline medium to prepare 2,4,6-tridisodiummalonate-triazine (2,4,6-TDSMTA) by replacing −C2H5 groups of COOC2H5 by Na, which was further neutralized by dilute HCl to obtain 2,4,6-trimalonicacid-triazine (2,4,6-TMATA). The TMATA was treated with PCl5(s) to form –COCl, which was treated with SDEM to form the G2.

An estimation of hydrophilic and hydrophobic interaction of aqueous urea, methylurea, dimethylurea and tetramethylurea from density and apparent molal volume at 30.0°C

Density (ρ) for 0.20–1.0 mol kg−1 of urea, 1-methylurea, 1,3-dimethylurea and 1,1,3,3-tetramethylurea solutions have been measured at an interval of 0.2 mol kg−1. Apparent molal volume (V φ, cm3 mol−1) is calculated from ρ values. Primary data were regressed and extrapolated to zero concentration for the limiting density (ρ0) and limiting apparent molal volume values for solute–solvent interactions.–CH3 (methyl) groups of N-methylureas weaken hydrophilic interaction and enhance hydrophobic interaction. The value of ρ0 and reflect the intermolecular forces due to electrostatic charge. The decreasing value of ρ0 and increasing value of with increasing number of–CH3 groups suggest some weak hydrophilic and strong hydrophobic interactions, so that the structure-breaking effect decreases. It was also found that with increasing concentration, the hydrophilic or hydrophobic interactions become stronger.

Effect Of Ionic Sizes Of Halide Anions Of Potassium Salts On Surface And Interfacial Tensions Of Benzene And Water Interfaces For Mutual Mixing

Surface tension (γ, mN/m) of potassium halide salts with water and interfacial tension (IFT) (±0.01 mN/m) of benzene interfaces with water are reported at 298.15 K temperature. The 0.1, 0.5 and 1.0 mol kg-1 potassium fluoride (KF), chloride (KCl), bromide (KBr) and potassium iodide (KI) solutions were studied. The KCl, KBr, KF and KI increased the surface tension by 5.2, 4.0, 3.1 and 3.0%, respectively, with salt–water interaction influence by anionic sizes. The surface tension of water from air–water to benzene–water interfaces is decreased by 51% due to the benzene–water mutual interaction with dipolar and π-conjugation. The KI, KF, KCl and KBr salts decrease the IFT by 63, 61, 61 and 56%, respectively, because of larger differences in sizes of the anions and the K+ with individual salt. The KI developed stronger interactions with an induced potential of a large sized I- anion that held the water engaged and integrated the aqueous phase with higher interfacial tension. The dipolar and π-conjugation interaction model is proposed with biphasic systems.