Model p-T-x diagrams for binary systems with hydrate formation in the supercritical fluid region

Model p-T-x diagrams for equilibrium systems with hydrate formation in the supercritical fluid region are proposed. Characteristic sections that illustrate isobaric and isothermal phase transitions are reported.     

Theory of the kinetics of adsorption taking into account heat evolution,where the rate of the process is limited by external mass and heat transfer

Conclusions The problem of the nonisothermal kinetics of adsorption for a granule of arbitrary shape, where the rate of the process is limited by external mass and heat transfer, was examined.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2831–2833, December, 1970.     

Role of edge-to-face interaction between aromatic rings in clathrate formation of 1-benzoyl-2-hydroxyindoline derivatives with benzene. X-ray crystal and PM6 analyses of the interaction

(4-Nitrophenyl- and 4-chlorophenyl)(2-hydroxy-3,3-dimethylindolin-1-yl)methanone (4a,b) serve as clathrate hosts for benzene guests. X-ray crystal analyses of the inclusion compounds of 4a and 4b with benzene indicate that the ‘edge-to-face interaction’ plays an important role in the formation of the inclusion complexes with benzene as well as in the host-host interactions. PM6 molecular orbital calculations were found to reproduce the characteristic structural features of both intra- and intermolecular edge-to-face interactions.     

Phase diagrams in the binary systems of tetracyanoethylene with mesitylene,durene and pentamethylbenzene

The phase diagrams of the binary systems of tetracyanoethylene (TCNE) with some methylbenzenes were determined by differential scanning calorimetry. In the durene-TCNE system a 11 complex was observed. The other two pairs of components form both 11 and 12 complexes. In all the systems, the complexes melted incongruently. Solid — solid phase transitions were found in the complexes in the pentamethylbenzene-TCNE system. The excess free energy of mixing of the liquid phase was estimated by fitting the modified van Laar equation to the measured liquidus lines. The enthalpy and the entropy of complex formation were used as the fitting parameters.

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Zusammenfassung Mittels DSC wurden die Phasendiagramme der binären Systeme aus Tetracyanoethylen (TCNE) mit einigen Methylbenzolen erstellt. Im System Duren-TCNE wurde ein 11 Komplex beobachtet. Die anderen beiden Komponentenpaare bilden sowohl 11 als auch 12 Komplexe. In allen Systemen schmelzen die Komplexe inkongruent. Im System Pentamethylbenzol-TCNE wurde für die Komplexe eine Fest-Fest-Phasenumwandlung gefunden. Durch Angleichen der modifizierten van Laar Gleichung an die gemessenen Liquidus-Kurven konnte die überschüssige freie Energie für das Mischens der flüssigen Phase geschätzt werden. Als Angleichparameter wurden Enthalpie und Entropie der Komplexbildung verwendet.

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We wish to thank M. Dankowski for his help in connecting the DSC apparatus to the microcomputer.     

Studies on the formation of hierarchical zeolite T aggregates with well-defined morphology in different template systems

In this paper, the disk-like and pumpkin-like hierarchical zeolite T aggregates consisted of primary nano-grains have been hydrothermally synthesized with and without the aid of the second template. The first template is used with tetramethylammonium hydroxide (TMAOH) and the second template is used with triethanolamine (TEA) or polyving akohol (PVA). A combination of characterization techniques, including XRD, SEM, TEM and N₂ adsorption–desorption to examine the crystal crystallinity, morphology and surface properties of hierarchical zeolite T aggregates. In the single-template preparation process, the two-step varying-temperature treatment has been used to improve the meso-porosity of zeolite T aggregates. In the double-template preparation process, the amounts of PVA or TEA on the crystallinity, morphology and meso-porosity of zeolite T aggregates have been studied. It has been proved that the interstitial voids between the primary grains of aggregates are the origin of additional mesopores of samples. The micro- and meso-porosities of samples prepared with and without the second template have been contrasted in detail at last. In particular, the sample synthesized with the addition of PVA presents a hierarchical pore structure with the highest S_ext value of 122 m²/g and V_meso value of 0.255 cm³/g.     

The interaction of monosubstituted benzenes with the stationary liquid in gas liquid chromatography

In gas liquid chromatography (GLC), the relative retention values log gamma was mainly expressed by van der Waals energy (the sum of the dispersion E(dis) and repulsive E(rep) energies) to the interactions between monosubstituted benzene derivatives and the nonpolar stationary liquid as squalane. The single exception was that of anilines, and it was corrected by the electrostatic energy (E(ES)) due to C-H/pi hydrogen bond. When the stationary liquid changed from the nonpolar to polar, log gamma was estimated by the inductive interaction energy (included in E(ES)) in addition to the sum of E(dis) and E(rep). In the benzene solution, the relative equilibrium values log K/K(o) introduced from the interactions between phenol and substituted benzene derivatives were estimated by E(ES). The E(ES) of COCH(3), CO(2)C(2)H(5) groups is especially originated in the excited dipole moments micro(e). The relative frequency values log nu/nu(o) derived from O-H or O-D stretching vibration of phenol or methanol-D gave the correlation to E(ES) as well as log K/K(o). That of anilines-methanol-D however had been out of a linear relation to E(ES). The cause is concluded that the aniline-methanol-D is making the proton transfer structure from the discussion about the proton affinity (PA) of the base.     

Continual stochastic description of systems with chemical reactions in the presence of a long-range interaction and concentration dependence of the electrical conductivity of electrolytes

It has been shown that recombination-dissociation processes influence the relaxation correction to the concentration dependence of the conductivity of electrolytes. A theoretical treatment has been carried out in the framework of the continual stochastic formalism of birth-and-death processes with a long-range interaction. Evaluations of the observed effects have been given and the possibility of their experimental measurement has been discussed. The question of the concentration dependence of the Hall effect has also been considered.     

The thermodynamic parameters of formation of ions in the interaction of alkylaluminum with electron donors

The thermodynamic parameters of formation of ions in the system AlMe₃ + electron donor (D) in the presence and absence of water microimpurities were determined. The structure of these ions was studied and their concentration in nonpolar media was estimated for the example of D = pyridine. The conclusion was drawn from the results of calculations that the participation of water resulted in a substantial increase in the concentration of ions.     

Many-orbital cluster expansion for the exchange-repulsion nonadditivity in the interaction of rare gas atoms. The neon trimer

Nonadditivity of the exchange repulsion for three neon atoms in the equilateral triangle configuration has been calculated in the first-order of the symmetry adapted perturbation theory. The relative nonadditive contribution to the first-order interaction energy has been found to be about twice as small as in the helium trimer. The many-orbital cluster partition of the exchange nonadditivity has been derived. It has been found that in the region of the van der Waals minimum about 95% of the exchange nonadditivity originates from the interaction of the L-shell electrons only. The five-orbital terms as well as terms of an order-higher than S³ have been found to be negligible. Approximate formulae for evaluation of the exchange repulsion nonadditivity has been proposed and discussed.This work was partly supported by the Polish Academy of Sciences within the project MR.I.9.     

1-Phenylethenol: The enol form of acetophenone. Preparation,ionization energy and the heat of formation in the gas phase

The enol form of acetophenone was generated in the gas phase and its ionization energy was determined as 8.01 ± 0.03 eV. The heat of formation of the enol was assessed as −46 ± 6 kJ.mol⁻¹. The enol is destabilized against acetophenone by 41 kJ.mol⁻¹.     

Reaction of exciplex formation in the gas phase. The role of weak attractive interactions in the initial state

The reaction of molecular exciplex formation in the gas phase is treated within the framework of the Landau-Zener approximation, with the assumption that the initial state of the reaction has a potential energy curve including both repulsive and attractive interactions. It is found that the introduction of attractive interactions into the initial state (commonly treated as a repulsive state) leads, in the case of dipole-induced-dipole interaction, to a “reverse” temperature dependence of the exciplex formation rate constant.     

The Mitsunobu reaction in the chemistry of nitrogen-containing heterocyclic compounds. The formation of heterocyclic systems (review)

Methods for the design of nitrogen-containing heterocyclic systems involving the formation of C-N bonds under the conditions of the Mitsunobu reaction are discussed. Dedicated to Afanasi Andreevich Akhrem on his 95th birthday. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 347–385, March, 2008.     

The lower self-ignition limit condition for hydrogen-oxygen mixtures in the kinetic region with taking into account surface modification by chain combustion products

The classic condition of the lower self-ignition limit in the kinetic region at a constant heterogeneous decay coefficient ɛ₀ was modified taking into account the degree of surface coverage by hydrogen atoms H_s and effective heterogeneous decay coefficient ɛ_eff. These values were determined by the ratio between the sticking χ and recombination γ coefficients. The condition γ = ɛ₀/2 was always fulfilled.     

Char formation from polyolefins. Correlations with low-temperature oxygen uptake and with flammability in the presence of metal halogen systems

The oxidative degradation and combustion of polypropylene were investigated by simultaneous thermal analysis (STA) and by flammability measurements. STA shows that, while halogen compounds and metal oxides invariably increase char formation from the polymeric substrate, metal chelates can act both as inhibitors and as promoters of carbonisation. In general, however, there appears to be a direct correlation between the effect of an additive on oxygen uptake and that on char formation. Pro-oxidants which catalyse char formation are effective condensed-phase flame retardants, as a result of their producing fewer volatile species from the polymer.     

Studies related to the head-maturation pathway of bacteriophages T4 And T2:II. nuclear disruption, protein synthesis and particle formation with the mutant 43-.30-.46-

We describe the aberrant phage multiplication of the triple conditional lethal mutant 43-(polymerase).30-(ligase).46-(exonuclease) of bacteriophage T4D in which phage DNA replication is arrested but some late protein synthesis occurs (33). The nuclear disruption is indistinguishable from wild type. Forty-five empty small and empty large particles are assembled per cell when the multiplicity of infection (m.o.i.) is 100. This number corresponds closely to the 38 phage equivalents of cleaved major head protein determined biochemically. By reducing the m.o.i. the number of observable particles decreases, reaching 1-5 per cell at an m.o.i. of 5(+5). The total synthesis of phage related proteins is not significantly dependant on the m.o.i. The synthesis of late proteins is about 10% of that of wild type at high m.o.i. and decreases with the m.o.i. The different early and late proteins do not show the same relative proportions as in wild type and respond differently to an increased m.o.i. These and other results are discussed with respect to the role of phage DNA in prehead assembly and head maturation.     

The role of electric interaction in the retention index cencept. Universal interaction indices for GLC,HPLC and TLC

Summary New electric interaction indices are proposed which can universally be used in GLC, HPLC and TLC. These indices can easily be calculated from a variety of the commonly used retention parameters, such as Kováts' retention indices, relative retention times, capacity factors, or R_F values, and the average molecular polarizabilities of the reference compounds. Calculation examples for polycyclic aromatic hydrocarbons and n-alkanes are given. Application of the electric interaction indices for studying the retention mechanism is demonstrated.     

Quantum dynamic description of dissipative energy transfer in light-harvesting complexes 1. The interaction model between chromophores and protein within the context of Redfield theory

Within the context of Redfield theory, a model that describes the dissipative dynamics of excitation energy transfer within natural and artificial light-harvesting complexes is proposed. On the basis of the dipole-dipole approximation of interaction between the chromophores and the protein, an analytical expression for the elements of the Redfield tensor is obtained, which contains no fitting parameters. This expression takes account of the spatial arrangement of the molecules, their relative orientation, and their excitation energy; it also presents a dependence of the dissipation rate on the temperature of the protein and its physical properties.     

Interactions in aqueous nonelectrolyte systems. Gibbs energy of interaction of the ether group with the hydroxyl group and the amide group

Freezing temperatures of dilute aqueous solutions of equimolar mixtures of 1,3,5-trioxane with myo-inositol, d-mannitol, cyclohexanol, formamide, and acetamide, and 1,4-dioxane with myo-inositol, d-mannitol, formamide, and acetamide have been measured. These data yield pairwise Gibbs energies of interactions between the molecules in an aqueous solution. Using the group additivity principle, the results also yield the pairwise functional group Gibbs energies of interaction for the ether group with the hydroxyl and amide group. These results have been combined with all available data from the literature to yield the Gibbs energy and enthalpy of interaction of amides, ethers, alcohols, and saccharides in aqueous solution.To whom correspondence should be addressed.