K. Dharmalingam

Solvent effects on hydrogen bonding between 1-pentanol and butyl methacrylate

The hydrogen bonding between 1-pentanol and butyl methacrylate (BMA) was investigated in n-heptane, CCl4, and benzene as solvents by using FTIR spectroscopic method. Utilizing Nash method the formation constant and free energy change of 1 : 1 complexes has been determined. The results show a significant dependence of the association constant upon the solvents used. The solvent effect on the formation of hydrogen bond equilibria is discussed in terms of specific interaction between the solute and the solvent. The variation of formation constant values with the solvents confirm the solvent environment which may affect the strength of intermolecular hydrogen bond formation between free O–H group of 1-pentanol and the carbonyl group of BMA (O–H···O=C).

Solvent effects on hydrogen bonding between ethyl methacrylate and 1-butanol

Abstract The hydrogen bonding between ethyl methacrylate dissolved in 1-butanol in inert solvents viz., n-heptane, carbon tetrachloride and benzene has been studied using FTIR spectroscopy. Utilizing Nash method the formation constant of the 1:1 complexes has been calculated. The formation constant and free energy change values vary with the solvents are observed in the present study confirms the solvent environment may affect the strength of intermolecular hydrogen bond formation between free hydroxyl group of 1-butanol and the carbonyl group of ethyl methacrylate.

Hydrogen Bonding Interaction between Methyl Methacrylate and Alcohols

Abstract The hydrogen bonding between methyl methacrylate and primary, secondary and tertiary alcohols has been studied by using FTIR spectroscopic method. The most likely association complex between alcohol and methyl methacrylate is 1 : 1 stoichiometric complex through the hydroxyl group of alcohol and the carbonyl group of methyl methacrylate. The formation constant of the 1 : 1 complexes has been calculated using Nash method. It appears that the primary alcohols have larger formation constant than the secondary and tertiary alcohols. The results show that the proton donating power of the alcohols decreases in the order primary > secondary > tertiary and the association constant increases with the increase in carbon chain of the alkyl group of alcohols.

Dielectric relaxation study of mixtures of alkyl methacrylates and 1-alcohols using time-domain reflectometry

Dielectric relaxation measurements on alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) with 1-alcohols (1-propanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) have been carried out using time-domain reflectometry (TDR) over the frequency range 10 MHz to 20 GHz at 303 K for different concentrations of alcohols. The dielectric parameters, namely the static dielectric constant (ε 0), the dielectric constant at microwave frequencies (ε ∞) and the relaxation time (τ) were determined. The Kirkwood correlation factor, which contains information regarding solute–solvent interaction and corresponding structural information, the excess permittivity and the excess inverse relaxation time were also determined. The values of the static dielectric constant and the relaxation time increase with the percentage of alkyl methacrylates in the alcohol, whereas the static dielectric constant decreases and the relaxation time increases with an increase in the alkyl chain length of both the methacrylates and the alcohols.

Dielectric relaxation of butyl acrylate—alcohol mixtures using time domain reflectometry

Dielectric relaxation measurements of butyl acrylate—alcohol mixtures at different concentrations and temperatures within the frequency range of 10 MHz to 10 GHz have been carried out using time domain reflectometry. Parameters such as the static permittivity, dielectric relaxation time, the Kirkwood correlation factor, the excess inverse relaxation time, and thermodynamic functions were determined and discussed to yield information on the molecular structure and dynamics of the mixture. The value of the dielectric properties decreases with increasing butyl acrylate concentration in alcohol and systematically varies with the length of alcohol alkyl chain. Negative values of the excess inverse relaxation time found for all concentrations and at all temperatures studied may indicate that the effective dipoles rotate slowly.

Femtosecond time-resolved x-ray diffraction from optical coherent phonons in CdTe(111) crystal

Coherent phonons excited in a CdTe(111) crystal by 70 fs laser irradiation have been investigated by femtosecond time-resolved x-ray diffraction. The longitudinal optical phonon with a frequency of approximately 5 THz near the Brillouin zone center has been detected as modulation in intensities of x-ray diffraction. Atomic displacement in the [111] direction in the coherent longitudinal optical phonon has been estimated.

Dielectric studies of alkyl acrylates with primary alcohols using time domain reflectometry

Binary polar–polar liquid mixtures of alkyl acrylates (methyl acrylate, ethyl acrylate and butyl acrylate) with primary alcohols (propan-1-ol, butan-1-ol and hexan-1-ol) were subjected to dielectric studies at 303 K for different concentrations using time domain reflectometry (TDR) over the frequency range from 10 MHz to 10 GHz. Static permittivity (ε0) dielectric constant at high frequency (ε∞) and relaxation time (τ) were found through dielectric measurements for different concentrations of each system. The Bruggeman dielectric factor, Kirkwood correlation factor and the excess inverse relaxation time were determined and discussed to yield information on the molecular interactions of the systems. Deviations from the linearity of various models suggest molecular association through hydrogen bonding between the −OH group of alcohols and C=O group of esters. The results also show a dependence of dielectric parameters on the alkyl chain length of both the alcohols and esters.

FTIR study of molecular interaction in butyl methacrylate-organic solvents mixtures

Summary FTIR spectroscopic study of butyl methacrylate (BMA) in different pure organic solvents were undertaken to investigate the solute–solvent interactions. The frequency of carbonyl stretching vibration ν(C=O) of BMA is correlated with the solvent properties such as the KBM parameter, the solvent acceptor number (AN), and the linear salvation energy relationships (LSER). The solvent-induced stretching vibration frequency shifts showed a better correlation with LSER parameters than AN. While no linear correlation between dielectric constants and the frequencies showed that the KBM relationship was unsuitable for this molecule. Also the solvent effect on the strength of hydrogen bond formation between free OH group of 1-butanol and C=O group of BMA is discussed in terms of local specific interaction between the solute and solvent.

Dielectric Relaxation Study of Amide-Alcohol Mixtures by Using Time Domain Reflectometry

Abstract Using time domain reflectometry (TDR), dielectric relaxation studies were carried out on binary mixtures of amides ( N -methylformamide (NMF) and N , N -dimethylformamide (DMF)) with alcohols (1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, and 1-decanol) for various concentrations over the frequency range from 10 MHz to 10 GHz at 303 K. The Kirkwood correlation factor and excess dielectric constant properties were determined and discussed to yield information on the molecular interactions of the systems. The relaxation time varied with the chain length of alcohols and substituted amides were noticed. The Bruggeman plot shows a deviation from linearity. This deviation was attributed to some sort of molecular interaction which may take place between the alcohols and substituted amides. The excess static permittivity and excess inverse relaxation time values varied from negative to positive for all the systems indicating that the solute-solvent interaction existed between alcohols and substituted amides for all the dynamics of the mixture.

Dielectric Relaxation Properties of Alcohols and Acrylic Esters

Abstract Dielectric relaxation of alcohols (1-propanol, 1-butanol, sec-butanol, tert-butanol, 1-pentanol, 1-heptanol, 1-octanol, and 1-decanol) with acrylic esters (methyl methacrylate, ethyl methacrylate, and butyl methacrylate) at 9.84 GHz was studied in n-heptane at 298 K. The result showed that 1:1 complex was predominant in these systems. The relaxation time showed a linear dependence with alkyl chain length of both alcohols and acrylic esters, but the dielectric constant showed a reverse trend. A comparative study of the free energy of activation for the dielectric relaxation and viscous flow suggested that a greater interference by neighboring atoms was observed in the process of viscous flow than in the process of dielectric relaxation, as the latter involved the rotational form of motion, whereas the viscous flow involved both rotational and translational forms of motion.