Aqueous solubilities of twelve chlorinated benzenes were determined by two methods. In one method, the solutions in water were prepared by a vigorous stirring method followed by n-hexane extraction and GC-ECD analysis. In the second method, HPLC was used to prepare the saturated solutions. Experimental results were compared with the predictive values, the relative standard deviations are around 10%. Most of the chlorinated benzenes exhibit water induced transformations. The transformation products were either isomeric or with higher and lower numbers of chlorine substituents. The transformation phenomena can be explained by polarity, symmetry, reactivity of the chlorine atoms, and hydrophobic interactions. The mechanism of the transformation is governed by the radical mechanism.

Yes / Literature data on solubilities of adamantane in organic solvents have been used to obtain properties, or descriptors, of adamantane. There is much less data on substituted adamantanes but we have been able to obtain descriptors for some 40 substituted adamantanes. These descriptors can then be used to estimate a wide range of physicochemical, environmental and other properties of the adamantanes. For the first time, the water-solvent partition coefficient and the gas-solvent partition coefficient into a large range of solvents, can be estimated, the latter being equivalent to Henry's Law constants. A variety of other important properties can also be estimated. These include vapor pressures, enthalpies of vaporization and sublimation, partitions from air and from blood into biological tissues, and skin permeability from water. The descriptors themselves are not exceptional. Adamantane itself has a rather low dipolarity, zero hydrogen bond acidity and a very low hydrogen bond basicity, in common with other multicyclic aliphatic compounds. These lead to adamantane being a very hydrophobic compound, as is evident from our estimated water-octanol partition coefficient.

The fluids that are operated above their critical temperature and pressure are known as supercritical fluids (SCFs). SCFs replaces the conventional organic solvents in the chemical processes due to their attractive properties such as liquid like densities, gas like diffusivities, negligible surface tension, lower viscosity and high compressibility. Carbon dioxide, being non-toxic, non-flammable with ambient critical temperature and moderate critical pressure, is the most widely used SCF in many chemical processes. Supercritical carbon dioxide (SCCO2) finds applications in industrial processes such as extraction and separation processes. The feasibility of a supercritical process can be determined from the solubility of solute in SCF. For the efficient design of a SCF process, the effects of temperature and pressure on the solubility of a solid should be examined thoroughly. In general, the solute of interest is not present alone; it is present along with many other components in the compound. The solute has to be extracted or separated from matrix of components. Therefore, it is important to determine the mixture solubilities in SCCO2. The mixture solubility of a solute is not same as that of pure component solubility. The presence of the other component alters the solubility of the solute to a greater extent; hence the effects of the other components present along with the solute, temperature and pressure need to be known to understand the mixture behavior of the solute in SCCO2. The solubilities of solid isomers (ortho-, meta-, para-) in SCCO2 vary to a greater extent. This huge difference in the solubilities of isomers is due to interactions between the molecules. The high solubility of an isomer in SCCO2 might be due to the solute-solvent interactions. The interactions between the molecules are significant in the solid mixtures solubilities in SCCO2. This research work focuses on experimental determination and modeling of mixture solubilities of solids in SCCO2. The solubilities of several pairs of isomers have been experimentally determined at different temperatures and pressures. These include the ternary solubilities of ntrophenols, nitrobenzoic acids and dihydroxy benzene isomers mixtures in SCCO2. The experimental solubilities of nitrophenol (meta- and para-) isomers mixture have been determined. This study includes the effect of temperature, pressure and each isomer on the ternary mixture solubilities of nitrophenol mixtures. The enhancements in the ternary solubilities of nitrophenols over their binary solubilities and the selectivity of SCCO2 for the nitrophenol mixture have been discussed in detail. The solubilities of dihydroxy benzene (ortho-: pyrocatechol, meta- : resorcinol and para-: hydroquinone) isomers in SCCO2 have been determined at various temperatures and pressures. The ternary solubilities of pyrocatechol and resorcinol and quaternary solubilities of pyrocatechol, resorcinol and hydroquinone mixtures in SCCO2 have been investigated. The effect of each isomer on the mixture solubilities of other isomers has been included in this work. Selectivity for dihydroxy benzene isomers and variation of solubilities enhancements with temperature and pressure has been presented in this study. The equilibrium mixture solubilities of nitrobenzoic acid isomers (meta- and para) mixture have been studied. The variation of mixture solubilities and their enhancements with temperature and pressure has been thoroughly analyzed. Selectivity of SCCO2 for this nitrobenzoic acid mixture has been studied in detail. The increase or decrease in the ternary solubilities of the solid mixtures that have been considered in this study is due to the interactions between the molecules. The ternary solubilities of m-nitrophenol increase whereas they decrease for pnitrophenol for the nitrophenol solid mixture. Quaternary solubilities of dihydroxy benzene isomers (pyrocatechol + resorcinol + hydroquinone) increases compared to their pure component solubilities. The ternary solubilities of pyrocatechol increases while resorcinol decreases over the pressure range at different temperatures (except 338 K) considered in this study. The mixture solubilities of p-nitrobenzoic acid of nitrobenzoic acid isomers increase to a greater extent. An average of separation efficiency of 70%, 85% and 90% has been observed for ternary solid mixtures of nitrophenol, nitrobenzoic acid and dihydroxy benzene isomers respectively. Modeling of high pressure multi-component systems is useful to understand the behavior of the mixtures. Moreover, the experimental determination of multicomponent solubilities of solids in SCCO2 is tedious and time consuming; hence the modeling of mixture solubilities is essential. The interactions between the molecules have been incorporated in the association theory and a five parameter equation with two constraints has been derived for binary systems. The new equation correlates the solubilities of m-dinitrobenzene in this study along with 72 other systems available in literature. Seven new model equations have been developed to correlate ternary (2 for cosolvent (solid + cosolvent + SCCO2) systems; 5 for solid mixtures in SCCO2) solubilities of solids in SCCO2. A new model equation for cosolvent ternary systems has been derived by using the concepts of association of molecules. The model equation contains seven adjustable parameters with three constraints and correlates mixture solubilities in terms of temperature, pressure, density and cosolvent composition. The interactions between the molecules have been included in the association theory then the number of parameters decreased to five with two constraints. The performance of the newly developed equations has been evaluated for 32 ternary systems with various cosolvents along with experimental data of mdinitrobenzene in methanol cosolvent of this study. The same association theory has been extended to ternary (solid mixtures + SCCO2) solubilities of solids in SCCO2 and two new equations have been derived with and without incorporating interactions between the molecules. Both the equations have five adjustable parameters with three constraints for the equation which has been derived from association theory alone and two constraints for the equation which has been derived by considering the interactions between the molecules in the association theory. A new model equation has been derived by combining solution model with Wilson activity coefficient model to account for nonidealities of the solute. This equation has four adjustable parameters and no constraints on the parameters. The non-idealities of both solutes in the solution model have been included and two more equations with no constraints on the parameters have been developed. One equation uses NRTL activity coefficient model which results in three adjustable parameters while the other equation with five parameters has been obtained from Wilson activity coefficient model for solid mixtures solubilities in SCCO2. The performance of the newly developed equations has been evaluated for the solid mixtures (ternary systems) in SCCO2. The equations with constraints make them limited for few systems and the equations with no constraints are able to correlate the solubilities of solids of all the ternary systems that are available in literature along with the generated ternary experimental data of this study. The quaternary solubilities of solids have been correlated by using a five parameter model equation which has been derived by combining solution and Wilson activity coefficient models. The equation for the quaternary systems does not have constraints on the parameters; hence can be applied for quaternary systems. The equation correlates the quaternary solubilities of solids in terms of temperature, pressure, density and cosolute compositions. Chapter 1 gives a brief introduction on the solubilities of solid mixtures and their behavior in SCCO2. Chapter 2 presents the experimental setup and the solubility data of binary, ternary and quaternary systems determined in this study. Chapter 3 focuses on the models that have been derived to correlate the solubilities of solids in SCCO2. Chapter 4 discusses in detail about the results obtained in this research work. Chapter 5 briefly summarizes the work and presents major conclusions. The new equations that have been developed here are first of its kind for the ternary and quaternary systems. These equations give information about the nonidealities of the systems. The nature of the interactions between the molecules can be determined from the parameters of the equations which incorporate interactions between the molecules. The multi-component solubilities of the solids can be correlated by using the semi-empirical equations that have been derived in this research.

The development of alternative binder systems for tungsten carbide (WC) based cemented carbides has again become of relevance due to possible changes in EU regulations regarding the use of Cobalt (Co). A framework for the ICME (Integrated Computational Materials Engineering) based Materials Design is presented to accelerate the development of alternative binder systems. Part one of this work deals with the design of the cemented carbide composite hardness. It has been shown that the intrinsic binder hardness is comparable to a bulk metal alloy and that based on the binder solubilities a solid solution strengthening model developed in this work can be employed. Using a method presented in this work the non-equilibrium, frozen-in binder solubilities can be obtained. Both the design of the binder phase and composite hardness is presented based on a general Materials Design approach. Part two deals with a multiscale approach to model the surface gradient formation. The experimentally missing data on liquid binder diffusion has been calculated using AIMD (Ab initio Molecular Dynamics). The diffusion through the liquid cemented carbide binder has to be reduced to an effective diffusion value due to the solid carbides acting as obstacles that increase the diffusion path. The geometrical reduction of the diffusion has been investigated experimentally using the SIMS (secondary ion mass spectroscopy) technique in WC-Nickel-58Nickel diffusion couples. The geometrical contribution of the so-called labyrinth factor has been proven by the combination of the experiments and in conjunction with DICTRA simulations using the precise liquid AIMD diffusivities. Unfortunately, despite the improved kinetic database and the geometrical diffusion reduction, the surface gradient formation cannot be explained satisfactory in complex cemented carbide grades. Additional, but so far unidentified, contributions have to be considered to predict the surface gradient thickness. / <p>QC 20170919</p>