A SAFT equation of state (EOS) combined with eight mixing rules was used to evaluate the capability of the SAFT approach for modeling the solubility of solids in supercritical fluids (SCFs). The results show that the SAFT approach gives good correlative accuracy in general, and the results are satisfactory when the three-parameter mixing rules are used, where the average absolute deviation of solid solubility in the SCF phase is normally smaller than 10%. The present work shows that the SAFT approach can be used to model solid-SCF equilibria, which gives slightly better correlative accuracy than the cubic EOSs.

The SAFT equation of state (EOS) combined with a one-parameter mixing rule was used to evaluate the capability of the SAFT approach for modeling the solubility of solid aromatic compounds in supercritical fluids (SCFs) with cosolvents. Binary interaction parameters were obtained by fitting the phase equilibrium data of the constituent binary systems. The SAFT EOS was used to predict the solubility of solids in carbon dioxide with cosolvents for five systems, and the overall average absolute relative deviation (AARD) was 20.43%. For the other 11 systems, the binary interaction parameters between the solids and the cosolvents were obtained by fitting the ternary solubility data, and the overall AARD was 16.45%. Comparison with the PRSV EOS showed that the SAFT EOS was superior in terms of both prediction and correlation. The present work demonstrates that the SAFT approach is useful for modeling the solubility of solids in SCFs with cosolvents with reasonable accuracy.

Aqueous liquefaction of Cunninghamia lanceolata, Fraxinus mandshurica, Pinus massoniana Lamb. and Populus tomentosa Carr. was carried out in an autoclave in the reaction temperature range of 553. 15-633. 15 K, where both non-catalytic and catalytic liquefaction were performed. The experimental results show that the lignin content has a large effect on the yield of liquefaction products in the noncatalytic liquefaction. The addition of K2CO3 as a catalyst can significantly reduce the residue yield for all the woods tested, while its effect on the heavy oil yield becomes weaker with decreasing amounts of lignin. The present study shows that a heavy oil yield of 30% coupled with a residue yield of less than 10% can be obtained for all the wood samples tested in the catalytic liquefaction.

A correlation for estimation of the aqueous solubility of organic compounds that is based on a training set of 120 chemicals is proposed. The new model proposed is predictive and requires only molecular connectivity indices in the calculations. The calculated results of the new model are comparable to those from the existing general solubility equation (GSE) and the Klopman-Zhu models. The new model was also applied to a testing set of 80 compounds, and the predictions show that the new model is reliable with good predictive accuracy. Because the new model does not require any experimental physicochemical properties in the calculation, it is simple and easy to apply. This work shows again that molecular connectivity indices are useful structural descriptors in quantitative structure-property (QSPR) studies in pharmaceutical research.

Metal-organic frameworks (MOFs) are thought to be a set of promising hydrogen storage materials; however, little is known about the interactions between hydrogen molecules and pore walls as well as the diffusivities of hydrogen in MOFs. In this work, we performed a systematic molecular simulation study on the adsorption and diffusion of hydrogen in MOFs to provide insight into molecular-level details of the underlying mechanisms. This work shows that metal-oxygen clusters are preferential adsorption sites for hydrogen in MOFs, and the effect of the organic linkers becomes evident with increasing pressure. The hydrogen storage capacity of MOFs is similar to carbon nanotubes, which is higher than zeolites. Diffusion of hydrogen in MOFs is an activated process that is similar to diffusion in zeolites. The information derived in this work is useful to guide the future rational design and synthesis of tailored MOF materials with improved hydrogen adsorption capability.

An open-cell model equation of state has been proposed, which relaxes the restrictions of the cell theory and allows more flexibilities in describing the structure of liquids. To test its capability, this equation has been applied to a variety of liquids, including 17 heavy molecular weight hydrocarbons, 10 organic solvents, and 15 polymers, in particular. The calculated density grand average AADp for the equation proposed here are 0.062, 0.057, and 0.054 per cent against the results for the equation of state by Simha and Somcynsky, 0.081, 0.093, and 0.072 percent for the above three groups of liquids, respectively. Good agreement between our calculated results and experimental data indicates that our model is an improvement over the Simha and Somcynsky equation of state, which has been evaluated as one of the best equations. Moreover, this equation can be easily extended to describe the properties of polymer solutions and polymer blends, which will be addressed in our subsequent paper.

The BeHeþn clusters with n=1-12 were investigated by ab initio calculations at the level of MP2 (full)/6-311+G (2d, 2p). All the most stable geometric structures were obtained. It is found that the first solvation shell around the beryllium ion core is completed at n=12, and the mechanism of cluster forming can be explained in terms of the solvated ion core model. The effects of basis set superposition error (BSSE) correction and zero-point vibrational energy (ZPE) correction to the energies were considered in the calculations.

Atomistic molecular dynamics simulations were performed to investigate the dependence of the self-diffusivity of liquid carbon tetrachloride (CCl4) confined in pillared pore materials on the pore width, porosityand the surface heterogeneityof the solid walls. The simulated results show that the self-diffusivityof liquid CCl4 does not increase monotonicallywith the pore width, but in an cillatorymanner to approach the bulk diffusivity. Moreover, the presence of activated sites characterizing the surface heterogeneity and the pillars reduces the self-diffusivityof liquid CCl4 confined in pillared pores. The effects of these factors on the self-diffusivityof fluids should be taken into account when a porous nanomaterial is designed or chosen for a certain process, in addition to their effects on other properties such as the adsorption capability.

A model for estimation of activity for efavirenz analogues with the K 103N mutant of HIV-1 RT was proposedin this work. The new model is predictive that requires only variable connectivity indices in the calculations. Compared with the existing models based on Monte Carlo simulation, the new model is easier to apply with better predictive accuracy, giving an r2 of 0.85, cross-validated Q2 of 0.82 and average error of only 0.23kcal/mol for the 47 efavirenz analogues concerned. This work also demonstrates that variable connectivity indices, a class of not widely recognizedstructural descriptors, are quite useful in the QSAR studies in the fields of pharmaceutics and biochemistry. These topological indices may play a more important role in these fields in future.

Based on White s renormalization group (RG) theory and the statistical associating fluid theory, a new equation of state (EOS) is derived, which can be used for a variety of fluids, including non-polar, polar and associating chain fluids both inside and outside the critical region. The new EOS, with the advantage of not introducing any additional adjustable parameter to the RG transform for real fluids, yields satisfactory critical exponent, vapor-liquid coexistence densities and vapor pressures, pVT isotherms, and isobaric specific heats for pure fluids. Especially, much better results are obtained than the original EOS in the nearest vicinity of the critical point.