Pure CCl4 Research Articles

Direct Observation of Scattering Angle Dependence of the Inelasticity Effect on the Interference Term Obtained from Time-of-Flight Neutron Diffraction Experiments

Abstract Scattering angle dependence has been experimentally examined for inelasticity effect on the intramolecular interference term observed from the time-of-flight neutron diffraction method. Internuclear distance and its root-mean-square displacement for liquid pure D2O, C6D6 and CCl4, have been determined from the least squares fitting analysis of the observed total interference term in the high-Q region. Although “apparent shrinkage” in the intramolecular distance has been observed obviously for the light nuclei pair at large scattering angle data (2θ > ca. 70°), it has been revealed that the apparent shrinkage in the D⋯D distance for D2O and C6D6, in which the inelasticity effect is expected to be most significant, is found to be suppressed well within ca. 1% for the data observed for the scattering angle below ca. 2θ < ca. 50°. Structural parameters determined have been compared with those determined from the gas-phase electron diffraction method in order to obtain insight of the effect of intermolecular interaction to molecular geometry in the liquid phase.

Vitamin D Improves Intestinal Barrier Function in Cirrhosis Rats by Upregulating Heme Oxygenase-1 Expression.

Intestinal barrier dysfunction always accompanies cirrhosis in patients with advanced liver disease and is an important contributor facilitating bacterial translocation (BT), which has been involved in the pathogenesis of cirrhosis and its complications. Several studies have demonstrated the protective effect of Vitamin D on intestinal barrier function. However, severe cholestasis leads to vitamin D depletion. This study was designed to test whether vitamin D therapy improves intestinal dysfunction in cirrhosis. Rats were subcutaneously injected with 50% sterile CCl4 (a mixture of pure CCl4 and olive oil, 0.3 mL/100 g) twice a week for 6 weeks. Next, 1,25(OH)2D3 (0.5 µg/100 g) and the vehicle were administered simultaneously with CCl4 to compare the extent of intestinal histologic damage, tight junction protein expression, intestinal barrier function, BT, intestinal proliferation, apoptosis, and enterocyte turnover. Intestinal heme oxygenase-1 (HO-1) expression and oxidative stress were also assessed. We found that vitamin D could maintain intestinal epithelial proliferation and turnover, inhibit intestinal epithelial apoptosis, alleviate structural damage, and prevent BT and intestinal barrier dysfunction. These were achieved partly through restoration of HO-1 and inhibition of oxidative stress. Taken together, our results suggest that vitamin D ameliorated intestinal epithelial turnover and improved the integrity and function of intestinal barrier in CCl4-induced liver cirrhotic rats. HO-1 signaling activation was involved in these above beneficial effects.

Two side liquid-cooled and passively Q-switched disk oscillator with nanosheets in flowing CCl4

A passively Q-switched and two side liquid-cooled Nd:YAG disk oscillator is demonstrated, which is operated at a pump pulse width of 300 μs and a pump repetition rate of 10 Hz. The coolant flows over the two large surfaces of the disk and will be passed through by laser beam, so it can also serve as a saturable absorber. For the unmodulated laser, the pure CCl4 was employed as coolant and a plane output mirror of 15 % transmission was employed. The maximum output energy of 795 mJ is realized corresponding to the optical–optical efficiency of 27.4 % and the slope efficiency of 30 %; for the graphene Q-switched laser, the CCl4 with graphene nanosheets was employed as coolant and a plane output mirror of 40 % transmission was employed. The maximum output energy of 376 mJ is realized corresponding to the optical–optical efficiency of 13 % and the slope efficiency of 18 %. The maximum average Q-switching repetition rate is 385 kHz, and the minimum average pulse width is 116 ns; for the MoS2 Q-switched laser, the CCl4 with MoS2 nanosheets was employed as coolant and a plane output mirror of 30 % transmission was employed. The maximum output energy of 486 mJ is realized corresponding to the optical–optical efficiency of 17 % and the slope efficiency of 22 %.The maximum average Q-switching repetition rate is 470 kHz, and the minimum average pulse width is 137 ns.

Fullerene C60 Trichloromethylation Through CCl4 Plasmalysis or Sonolysis

The trichloromethylation of C60 fullerene was achieved either under plasmalysis conditions, i.e. by arcing a solution of C60 in CCl4 between two graphite electrodes, or by sonolysis of C60 in CCl4. The resulting products were studied by UV–VIS and FT-IR spectroscopy as well as by thermogravimetric analysis in comparison to the trichloromethyl adducts formed by radiolysis or photolysis of C60 in CCl4. A reference study on the plasmalysis of pure CCl4 has revealed the formation of carbon soot and hexachlorobenzene. The formation of the latter compound was suppressed when C60 was present in CCl4.

Surface and Interfacial Properties of Nonaqueous‐Phase Liquid Mixtures Released to the Subsurface at the Hanford Site

Surface and interfacial tensions are key parameters affecting nonaqueous‐phase liquid (NAPL) movement and redistribution in the subsurface after spill events. In this study, the impact of major additive components on surface and interfacial tensions for organic mixtures and wastewater was investigated. Organic mixture and wastewater compositions were based on CCl4 mixtures released at the U.S. Department of Energy's Hanford site, where CCl4 was discharged simultaneously with dibutyl butyl phosphonate, tributyl phosphate, dibutyl phosphate, and a machining lard oil. A considerable amount of wastewater consisting primarily of nitrates and metal salts was also discharged. The measured tension values revealed that the addition of these additive components caused a significant lowering of the interfacial tension with water or wastewater and the surface tension of the wastewater phase in equilibrium with the organic mixtures, compared with pure CCl4, but had minimal effect on the surface tension of the NAPL itself. These results led to large differences in spreading coefficients for several mixtures, where the additives caused both a higher (more spreading) initial spreading coefficient and a lower (less spreading) equilibrium spreading coefficient. This indicates that if these mixtures migrate into uncontaminated areas, they will tend to spread quickly but will form a higher residual NAPL saturation after equilibrium than pure CCl4 With time, CCl4 probably volatilizes more rapidly than other components in the originally disposed mixtures and the lard oil and phosphates would become more concentrated in the remaining NAPL, resulting in a lower interfacial tension for the mixture. These results show that the behavior of organic chemical mixtures should be accounted for in flow and transport models.

Fluorescence quenching and laser photolysis of dipyrrolylbenzenes in the presence of chloromethanes

Fluorescence quenching of 1,4-bis(1H-pyrrol-1-yl)benzene, 1-(1H-pyrrol-2-yl)-1-(1-vinyl-1H-pyrrol-1-yl)benzene, and 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene with chloromethanes (methylene chloride, chloroform, and carbon tetrachloride) in solvents with different polarities follows electron-transfer mechanism. The occurrence of an electron-transfer step is confirmed by formation of short-lived pyrrolylbenzene radical cations. An exception is quenching of fluorescence of 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene in n-hexane in the presence of CCl4 and CHCl3 and in pure CCl4. In this case, neutral 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene·-Cl radical is formed via recombination of 1,4-bis(1-vinyl-1H-pyrrol-2-yl)benzene radical cation and chloride anion. A relation was found between the nature of the short-lived species detected by laser photolysis and stable product obtained by stationary photolysis.

Interaction of the organic tin chloride with the liquid model membranes

The objective of the work was to investigate the effect of organic tin chloride (C3H7)3SnCl on the electric parameters of membranes in the form of filters of the company Synpor (Czech Republic) impregnated with various fatty acids, dissolved with carbon tetrachloride (CCl4). Three carboxylic acids were used in the study: palmitic, arachidic and oleic, and dissolvent of the acids (CCl4) as well as butylene ester of lauric acid. In all cases, introduction of tin chloride of constant concentration amounting to 0.15 mM to the measurement chamber resulted in induction of membrane voltage. In case of pure lauric acid and CCl4, the voltage reached the maximum value and then decreased to a certain constant value. In the case of all acids dissolved in CCl4, the voltage increased only up to a certain constant value. Voltage drop (below the value) was observed after application of appropriately high concentration of tin chloride, in case of membranes impregnated with the mixture of lauric acid ester with CCl4 and palmitic acid with CCl4. The study also demonstrated that electrical resistance of membranes impregnated with carboxylic acid increased in the presence of tin chloride and decreased in case of membranes impregnated with lauric acid ester. However, electric capacities of membranes did not significant change.

Phenol-benzene complexation dynamics: Quantum chemistry calculation, molecular dynamics simulations, and two dimensional IR spectroscopy

Molecular dynamics (MD) simulations and quantum mechanical electronic structure calculations are used to investigate the nature and dynamics of the phenol-benzene complex in the mixed solvent, benzene/CCl4. Under thermal equilibrium conditions, the complexes are continuously dissociating and forming. The MD simulations are used to calculate the experimental observables related to the phenol hydroxyl stretching mode, i.e., the two dimensional infrared vibrational echo spectrum as a function of time, which directly displays the formation and dissociation of the complex through the growth of off-diagonal peaks, and the linear absorption spectrum, which displays two hydroxyl stretch peaks, one for the complex and one for the free phenol. The results of the simulations are compared to previously reported experimental data and are found to be in quite reasonable agreement. The electronic structure calculations show that the complex is T shaped. The classical potential used for the phenol-benzene interaction in the MD simulations is in good accord with the highest level of the electronic structure calculations. A variety of other features is extracted from the simulations including the relationship between the structure and the projection of the electric field on the hydroxyl group. The fluctuating electric field is used to determine the hydroxyl stretch frequency-frequency correlation function (FFCF). The simulations are also used to examine the number distribution of benzene and CCl4 molecules in the first solvent shell around the phenol. It is found that the distribution is not that of the solvent mole fraction of benzene. There are substantial probabilities of finding a phenol in either a pure benzene environment or a pure CCl4 environment. A conjecture is made that relates the FFCF to the local number of benzene molecules in phenol's first solvent shell.

Physicochemical investigation of the solubilization of ytterbium nitrate in AOT reverse micelles and liquid crystals

A wide investigation of the solubilization of the water-soluble salt Yb(NO3)3 in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles and AOT liquid crystals has been carried out. After saturation of water/AOT/organic solvent w/o microemulsions with pure Yb(NO3)3, the Yb(NO3)3/AOT composites were prepared by complete evaporation under vacuum of the volatile components (water and organic solvent) of the salt-containing microemulsions. It was observed that these composites can be totally dissolved in pure n-heptane or CCl4, allowing the solubilization of a noticeable amount of Yb(NO3)3 in quite dry apolar media. By UV–vis–NIR, FT-IR, and 1H NMR spectroscopies, some information on the state of Yb(NO3)3 within AOT reverse micelles were acquired, whereas by small angle X-ray scattering (SAXS), it has been ascertained that Yb(NO3)3 is quite homogeneously distributed as very small clusters among the reverse micelles. An analysis of SAXS and wide-angle X-ray scattering spectra of Yb(NO3)3/AOT composites leads to the hypothesis that, also in these systems, Yb(NO3)3 is dispersed in the surfactant matrix as very small clusters.

Partition Coefficients and Equilibrium Constants of Crown Ethers between Water and Organic Solvents Determined by Proton Nuclear Magnetic Resonance

The extraction of water by several crown ethers into chloroform + carbon tetrachloride mixtures has been investigated using a proton NMR technique. The equilibrium is well described by formation of a 1:1 water−crown complex in rapid exchange with uncomplexed ligand and water. The fraction (k) of crown ether complexed with water increases with crown cavity size, varying from (15 ±1)% for 12-crown-4 to (97 ± 5)% for 18-crown-6. Addition of carbon tetrachloride to chloroform lowers the k value for all crown ethers in equilibrium with water, and the value is close to zero in pure CCl4. The partition coefficient follows the opposite trend: the amount of crown ether in the organic phase increases with the percentage of CCl4 in this phase. The chemical shifts of free and complexed water also vary with solvent composition. Interaction of water with crown ether depends on solvation environment and may play a significant role in liquid−liquid extraction of metal ions using macrocyclic polyethers as extractants.

Role of the orientational subsystem in the expansion of pure SF6, CHCl3, C6H6, CCl4, and N2O with Kr impurity

The linear expansion coefficients of solid bulk samples of N2O with 5% Kr impurity are measured by an absolute dilatometric method in comparison with pure N2O in the temperature range 80–150 K. An additional unusual orientational effect is discussed. An analysis of the data from measurements of the linear expansion coefficients of pure solid SF6, CHCl3, C6H6, and CCl4 in comparison with solid Xe in the temperature range 80–170 K is carried out in order to determine the role of molecules’ orientational disordering in the thermal expansion of the given condensed systems. The results are discussed in connection with the problem of determining the contribution of orientational subsystems with different types of molecular symmetry to the total thermal expansion and its behavior in various temperature intervals of solid phase existence.

Effect of Temperature and Concentration on Self-Association of Octan-3-ol Studied by Vibrational Spectroscopy and Dielectric Measurements

The effects of temperature and concentration on self-association of octan-3-ol both in pure liquid and CCl4 solution have been studied by two-dimensional (2D) Fourier transform near-infrared (FT-NIR) correlation spectroscopy, conventional FT-IR spectroscopy, and dielectric measurements. The interpretation of 2D correlation spectra was supported by simulation studies. A particular attention has been paid for comparison of the present results with that previously published for octan-1-ol. The obtained results indicate that population of the free OH groups changes faster than that of the associated species with increasing temperature. This results from the fact that in the open-chain multimers the terminal hydrogen bonds break easier than the interior ones. The open-chain dimers are less favorable than the higher associates due to the lack of the cooperativity effect. Hence, these species appear as a result of temperature-induced dissociation of higher multimers in concentrated solutions and in neat alcohols. At low concentration of alcohol in CCl4 the nonpolar (cyclic) species dominates. An increase in the concentration of the sample increases the number and length of the linear associates, and this effect is more pronounced for primary alcohols. In octan-1-ol, formation of the linear associates is favored, whereas in octan-3-ol the cyclic species dominates. The present results reveal the presence of at least two kinds of associated species and argue against frequently assumed equilibrium between the monomers and one kind of associates at all concentrations.

Simulation for the primary electronic donor of photosystem IIin vitro

Histidine coordinated to Chi a is a distinct characteristic of Chl ain vivo. By using histidine analogue of 1-methylimidazole (C4H6N22) and measuring the UV/vis absorption, CD and MCD spectra of the interaction between C4H6N2 and Chl a in CCI4, we have obtained that: (i) In pure CCl4 solvent, Chl a molecule is in five-coordinate state, and two Chl a molecules form an asymmetric compact-dimer with strong coupling interaction. We propose that the two Chl a molecules are connected by two unequally coordinated Mg-O bonds (the two oxygen atoms come from the C=O of C131 keto and C17 ester, respectively); (ii) when the molar ratio of C4H6N2/Chl a is 0.5 or 1 (corresponding to 2Chl a · 1C4H6N2 and 2Chl a · 2C4H6N2, respectively), significant changes have been observed in the absorption, CD and MCD spectra, which indicate that the Chl a remains in dimer form, but the coupling interaction between them reduces greatly. We postulate that C4H6N2 replaces the ligation of C=O of C17 ester and C131 keto to Mg atoms sequentially. The two Chl a molecules linked by two weakly interacted Mg…O bonds form a relaxed-dimer. The structure of the model is essentially similar to that of the primary electronic donor, P680, of photosystem II in high plants and algae.

Molecular structure and vibrational spectra of trimethylarsenite

The molecular structure and vibrational spectra of trimethylarsenite were studied by gas phase electron diffractometry and IR and Raman spectroscopv. The configuration of the O-methyl groups with respect to the lone electron pair of the arsenic atom is established to be close to gosh-gosh-trans. The main geometrical parameters are: bond lengths (ra, A) As-O 1.780, C-0 1.451, and C-H 1.101; bond angles (deg) As-O-C 115.0, O-As-0 99.5, and O-C-H 115.3. The experimental IR and Raman spectra were obtained for pure liquid and CCl4 solution. The frequencies and forms of normal vibrations were calculated.

Two Distinct Solvated Structures of p-Nitroaniline in Acetonitrile

Abstract The presence of two distinct forms of p-nitroaniline (pNA) associated with solvent acetonitrile (AN) molecules is shown by using an SVD (Singular Value Decomposition) analysis of the UV-VIS spectra of pNA in AN/CCl4 mixed solvents. All the three species (including the unassociated form in pure CCl4) observed have varying degrees of intramolecular charge transfer due to the association.

Vibrational spectra and electron diffraction study of the structure and internal rotation of N,N-diethylcyanamide

Structural parameters, internal rotation parameters, and frequencies of normal vibrations of N,N-diethyl-cyanamide were obtained. The geometrical structure and internal rotation were studied by gas phase electron diffractometry. The configuration of the bonds of the amine nitrogen atom were found to be close to pyramidal: λ∈CNC 111.8°, λCNC 109.1°; the main bond lengths are (A): N∈C 1.174; ∈C−N 1.349; C−N 1.479; C−C 1.536. A map of changes in the conformation energies due to rotation of ethyl groups around the N−C bonds is constructed. Experimental IR and Raman spectra of pure liquid and CCl4 solution were measured. The frequencies and forms of normal vibrations are calculated, and the force constants are determined.

Pulsed Terahertz Transmission Spectroscopy of Liquid CHCl3, CCl4, and their Mixtures

The frequency-dependent absorption coefficient of CHCl3, CCl4, and their mixtures are measured by pulsed terahertz time domain transmission spectroscopy. The absorbance spectrum for neat CHCl3 is shown to compare well with existing experimental data including coverage of the previously difficult to access 0.3−0.9 THz range. Furthermore, fitted curves to the absorbance spectra of the liquid mixtures, based on mole fraction weighted sums of the absorption coefficients of pure CHCl3 and CCl4, indicate the presence of a bulk dipole reducing mechanism, possibly due to clustering of CHCl3 molecules about CCl4. An algebraic extension of the mole fraction weighted fits allows discrimination between relative strengths of the various bimolecular absorption processes. The integrated absorption coefficient for collisionally induced absorption of CHCl3−CCl4 collisions was found to be less than that for CHCl3−CHCl3 collisions by 2.6 ± 0.4 THz cm-1 (integrated absorption coefficient units). Finally, a new procedure for ...

Exchange kinetics between the adsorbed state and free solution: poly(methyl methacrylate) in carbon tetrachloride

Adsorption and desorption rates at high surface coverage are reported for poly(methy1 meth- acrylate) (PMMA) adsorbed from dilute carbon tetrachloride solution (1 mgmL-l) onto a single silicon oxide substrate at 30.0 OC. The method of measurement was infrared spectroscopy in attenuated total reflection. The polymer fractions studied were deuterio (d-PMMA) and protio (h-PMMA) with matched degrees of polymerization N, = 570 and 640, respectively. No adsorption isotope effect was expected, nor noted experimentally. The rapid adsorption of d-PMMA onto the initially bare surface was followed for 1 h, at which time the ambient solution was changed either to a solution of h-PMMA or to pure CCld. De- sorption of d-PMMA after this time was linear in the elapsed time over 6 h, with rate on the order of l % h-1, and this rate was the same into a solution of h-PMMA as into pure CCl4 at 30 and 40 OC. The infra- red bound fraction, Le., the fraction of segments in direct contact with the surface, was also measured. During adsorption onto initially bare surfaces, the average bound fraction took the constant level p = 0.25 throughout the experiments. However, for h-PMMA penetrating the preadsorbed d-PMMA layer after this polymer was allowed to adsorb for 1 h, the average bound fraction was p = 0.1 at elapsed times of minutes but rose to p = 0.2 after 6 h. This indicates that incoming chains underwent spreading at the surface. Control experiments with stearic acid in CCl4 showed that adsorption-desorption kinetics in this system were more rapid than the experimental time scale. This suggests that despite slow rearrangements of the overall chains, rearrangements may have been rapid at the level of individual segments. The surface excess adsorbed amount in this PMMA system was dominated by sluggish relaxation and, by inference, by metastable nonequilibrium states.

Sol-Gel Method Using Carbon Tetrachloride as Drop-Formation Medium for Producing Large ThO2-Base Microspheres

A method is described for producing large, spherical ThO2 or (Th, U)O2 particles by a sol-gel process. In the method CCl4 is used as a sol-drop formation medium and ammonia as a gelling agent. Source sols used are lighter than CCl4. So, sol-drops are formed in pure CCl4 at the bottom of a gelation column. Thereafter they ascend in ammoniac CCl4 with solidification of their surface and teach interface between the ammoniac CCl4 and concentrated NH4OH which is placed on the CCl4 to complete gelation of the drops. For continuous recovery of the resulting gel-spheres from the interface, special devices are developed. By using this apparatus, large microspheres of ThO2 and (Th, U)O2 are obtained without cracking; maximum attainable diameters of sintered spheres are 1,000 and 1,300 μm, respectively. Their sphericities are less than 1.1 even for 1,000 μm diameters.

Sol-gel method using carbon tetrachloride as drop-formation medium for producing large ThO2-base microspheres.

A method is described for producing large, spherical ThO2 or (Th, U)O2 particles by a sol-gel process. In the method CCl4 is used as a sol-drop formation medium and ammonia as a gelling agent. Source sols used are lighter than CCl4. So, sol-drops are formed in pure CCl4 at the bottom of a gelation column. Thereafter they ascend in ammoniac CCl4 with solidification of their surface and teach interface between the ammoniac CCl4 and concentrated NH4OH which is placed on the CCl4 to complete gelation of the drops. For continuous recovery of the resulting gel-spheres from the interface, special devices are developed. By using this apparatus, large microspheres of ThO2 and (Th, U)O2 are obtained without cracking; maximum attainable diameters of sintered spheres are 1,000 and 1,300 μm, respectively. Their sphericities are less than 1.1 even for 1,000 μm diameters.