Kinetic study of a complex triangular reaction system in alkaline aqueous-ethanol medium using on-line transmission FTIR spectroscopy and BTEM analysis.

The kinetics of the base-catalyzed reaction of methyl 4-hydroxybenzoate in aqueous-ethanol solvent medium was studied and analyzed via combined on-line transmission FTIR spectroscopy and Band-Target Entropy Minimization (BTEM) technique. This reaction is considered complex since it involves simultaneous hydrolysis and ethanolysis reactions of methyl 4-hydrozybenzoate (MP) to form ethyl 4-hydroxybenzoate (EP) as an intermediate and sodium 4-hydroxybenzoate as a final product. The pure component spectra of the reactive species involved in the reaction were reconstructed using BTEM technique.

Self-association of acetic acid in dilute deuterated chloroform. Wide-range spectral reconstructions and analysis using FTIR spectroscopy, BTEM, and DFT.

The binary solution of acetic acid in CDCl(3) was studied at room pressure on the interval T = 293-313 K with a series of acetic acid concentrations up to 0.16 M. In-situ Fourier transform infrared (FTIR) spectroscopy measurements on the interval of 400-3800 cm(-1) were utilized as the analytical method to monitor the spectral changes due to self-association of acetic acid.

Concurrent synergism and inhibition in bimetallic catalysis: catalytic binuclear elimination, solute-solute interactions and a hetero-bimetallic hydrogen-bonded complex in rh-mo hydroformylations.

Hydroformylations of cyclopentene and 3,3-dimethylbut-1-ene were performed using both Rh(4)(CO)(12) and (eta(5)-C(5)H(5))Mo(CO)(3)H as precursors in n-hexane at 298 K. Both stoichiometric and catalytic hydroformylations were conducted as well as isotopic labeling experiments. Six organometallic pure component spectra were recovered from the high-pressure FTIR experiments, namely the known species Rh(4)(CO)(12), (eta(5)-C(5)H(5))Mo(CO)(3)H, RCORh(CO)(4), and the new heterobimetallic complexes RhMo(CO)(7)(eta(5)-C(5)H(5)), a weak hydrogen bonded species (eta(5)-C(5)H(5))Mo(CO)(3)H-C(5)H(9)CORh(CO)(4), and a substituted RhMo(CO)(7-y)(eta(5)-C(5)H(5))L(y), where y = 1 or 2 and L = (pi-C(5)H(8)).

A new modified parachor model for predicting surface compositions of binary liquid mixtures. On the importance of surface volume representation.

Differences in composition between the surface region and the bulk region for binary liquids can occur due to preferential adsorption, and such surface enrichment can influence mass and heat transport across the interface. In order to investigate surface enrichment, reliable methods for predicting surface compositions are required. In this study, an approach based on a modified parachor model is developed in order to provide a generally more accurate prediction for the surface composition.

Combined on-line transmission FTIR measurements and BTEM analysis for the kinetic study of a consecutive reaction in aqueous-organic phase medium.

Combined on-line transmission FTIR spectroscopy and band-target entropy minimization (BTEM) analysis were employed in order to monitor and analyze the kinetics of the alkaline hydrolysis reaction of diethyl phthalate (DEP) in aqueous-ethanol solvent mixture. This reaction is irreversible and involves two consecutive steps with the formation of the observable mono-ion intermediate species. The pure component mid-FTIR spectra of the reactive species involved in this reaction, namely DEP, mono-ion intermediate and di-ion product were successfully reconstructed using BTEM.

Combined online spectroscopic, calorimetric, and chemometric analysis: reaction enthalpy determinations in single and parallel reactions.

Calorimetry and signal processing: Vibrational spectroscopies, heat-flow microcalorimetry, and multivariate analysis are combined to decouple the reaction enthalpies of parallel reactions [picture: see text]. This methodology allows the evaluation of reaction enthalpy from complex systems without recourse to conventional kinetic modeling. Simultaneous in situ/online spectroscopy and heat-flow measurements as well as multivariate analyses are performed, apparently for the first time, to determine heats of reaction for single and parallel reactions.

Experimental dipole moments for nonisolatable acetic acid structures in a nonpolar medium. A combined spectroscopic, dielectric, and DFT study for self-association in solution.

Acetic acid can exist in many possible structural forms depending on its surrounding medium. A recently developed inverse problem methodology (J. Phys.

Remote monitoring of a multi-component liquid-phase organic synthesis by infrared emission spectroscopy: the recovery of pure component emissivities by band-target entropy minimization.

A liquid-phase cycloaddition reaction near ambient temperature involving dimethyl acetylenedicarboxylate (DMAD) and cyclopentadiene (CP) as reactants was measured using a conventional Fourier transform infrared (FT-IR) spectrometer with an emission accessory. Two semi-batch experiments were performed and a total of 55 spectra were collected using a DTGS detector. Band-target entropy minimization (BTEM), a pure component spectral reconstruction technique, was applied to analyze the data set to retrieve the pure component emission spectrum from the reaction system.

On the determination of partial molar polarizations and dipole moments of solutes from multicomponent solutions alone: experimental and model development using deutero-labeled organic compounds.

A general inverse problem methodology is introduced to determine the partial molar polarizations and the dipole moments of individual solutes from multicomponent solutions alone. A model quaternary system consisting of three deuterated solutes, for example, acetone-d6, acetonitrile-d3, and dimethylformamide-d7 in cyclohexane at 298.15 K and 0.

Three-terminal capacitance cell for stopped-flow measurements of very dilute solutions.

A capacitance cell has been designed, constructed, and tested for stopped-flow measurements of very dilute low-relative permittivity liquid solutions. The capacitance cell utilizes a three-terminal design and is connected to ultrahigh sensitivity capacitance bridge. The cell was designed for operating conditions T = 243.

The direct determination of partial molar volumes and reaction volumes in ultra-dilute non-reactive and reactive multi-component systems using a combined spectroscopic and modified response surface model approach.

Two experimental multi-component organometallic systems were studied, namely, (1) a non-reactive system consisting of [Mo(CO)(6)], [Mn(2)(CO)(10)], and [Re(2)(CO)(10)] in toluene under argon at 298.15 K and 0.1 MPa and (2) a reactive system consisting of [Rh(4)(CO)(12)] + PPh(3)--> [Rh(4)(CO)(11)PPh(3)] + CO in n-hexane under argon at 298.