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Research of the catalysts activity in the reactions of model compounds and their mutual influence was carried out. Quinoline is able to promote the hydrodesulfurization reaction of dibenzothiophene (DBT), being a source of hydrogen in the system at 260 °C. The possibility of intermolecular hydrogen transfer reactions in the reactions of tetrahydroquinoline and DBT is shown.

NiMoW/P-Al2O3catalysts were synthesized with a different ratio of Mo:W (W-free sample, Mo:W = 2:1, Mo:W = 1:1, Mo:W = 1:2 and Mo-free sample) and various P2O5contents in the carrier (up to 5 wt%). The surface of the sulfide phase of the samples was investigated by means of high-resolution transmission electron microscopy (HR TEM) and X-ray photoelectron spectroscopy (XPS). The catalytic activity of patterns was estimated in the reactions of hydrodesulfurization of dibenzothiophene (DBT) and hydrogenation of naphthalene. The results are presented in the form of three-dimensional diagrams “P2O5content—ratio Mo/W—catalytic activity” or “P2O5content—ratio Mo/W—property”. The influence of the phosphorus content on the maximum peak position of the binding energy S2p/1 of the S2−atomic group for the investigated systems is shown. Comparison of the shape of the curve of changes in the binding energy with the previously presented results on the catalytic activity of the samples in the HDS of a vacuum gas oil allows us to conclude that phosphorus is able to change the electronic state of the active phase of the catalysts, which leads to a change in their catalytic activity in the reactions of HDS.

Activity coefficients at infinite dilution %@mt;sys@%γ%@sx@%%@ital@%i%@rsf@%%@be@%∞%@sxx@%%@mx@% of alkanes, alkenes, and alkylbenzenes as well as of the linear and branched C1−C6 alcohols, esters, and aldehydes in the ionic liquid 1-methyl-3-octyl-imidazolium tetrafluoroborate were determined by gas chromatography using the ionic liquid as the stationary phase. The measurements were carried out at different temperatures between 302 K and 396 K. Data points (204) have been obtained for 51 solutes. From the temperature dependence of the limiting activity coefficients, partial molar excess enthalpies at infinite dilution %@mt;sys@%%@ital@%H%@rsf@%%@sx@%%@ital@%i%@rsf@%%@be@%E,∞%@sxx@%%@mx@% of the solutes in the ionic liquid have been derived.

Activity coefficients at infinite dilution (%@mt;sys@%γ%@sx@%%@ital@%i%@rsf@%%@be@%∞%@sxx@%%@mx@% ) of alkanes, alkenes, and alkylbenzenes as well as of the linear and branched C1−C7 alcohols, esters, and aldehydes in the ionic liquids 1-methyl-3-butyl-imidazolium bis(trifluoromethyl-sulfonyl) imide were determined by gas chromatography using the ionic liquid as stationary phase. The measurements were carried out at different temperatures between 302 K and 385 K. From the temperature dependence of the limiting activity coefficients, partial molar excess enthalpies at infinite dilution (%@mt;sys@%%@ital@%H%@rsf@%%@sx@%%@ital@%i%@rsf@%%@be@%%@ital@%E%@rsf@%,∞%@sxx@%%@mx@% ) of the solutes in the ionic liquids have been derived.

The vapor pressures and molar enthalpies of vaporization, %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% Hm, of 2-amino-ethanol, 2-(methylamino)-ethanol, 2-(ethylamino)-ethanol, 2-(dimethylamino)-ethanol, and 2-(diethylamino)-ethanol have been determined using the transpiration method. The strength of intermolecular hydrogen bonding in ethanolamines has been derived and discussed in terms of the difference between the enthalpy of vaporization of an alkanolamine and an appropriate homomorph (alkylamine).

Vapor−liquid equilibria of binary mixtures containing high-boiling solutes methoxy-benzene, (hydroxymethyl)-benzene, 1,2-ethanediol, and 1,4-butanediol and ionic liquid [EMIM][NTf2] were studied by using the transpiration method. VLE measurements were carried out over the whole concentration range at different temperatures between 298 K and 363 K. Activity coefficients γi of these solvents in the ionic liquid have been determined from these data and are described formally by using the NRTL equation. In addition, vapor pressures of pure solutes methoxy-benzene, (hydroxymethyl)-benzene, 1,2-ethanediol, and 1,4-butanediol have been measured as a function of temperature, and their enthalpies of vaporization have been obtained.

Chemical equilibrium of the reactive systems of benzyl alcohol with tert-alkyl ethers was studied in the liquid phase in the temperature range (298 to 373) K and with a cation exchanger Amberlist 15 as a catalyst. Enthalpies of reactions involving benzyl alcohol were obtained from the temperature dependence of the equilibrium constants according to the Second Law and used to derive averaged standard enthalpies of formation of benzyl alcohol %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@fn;(;vis;full;auto@%l,298.15K%@fnx;);vis;full@%%@sbx@%%@mx@% = −(154.5 ± 1.7) kJ·mol^-1 in the liquid state. Vapor pressures and enthalpy of vaporization, %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% Hm(298.15 K), of benzyl alcohol were determined using transpiration method. The latter value, together with the reliable literature data, provided an averaged result %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% Hm(298.15 K) = (65.75 ± 0.51) kJ·mol^-1. Both averaged results for %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@fn;(;vis;full;auto@%l,298.15K%@fnx;);vis;full@%%@sbx@%%@mx@% and %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% Hm(298.15 K) were used to calculate and to recommend the value of enthalpy of formation of benzyl alcohol in the gaseous state %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@fn;(;vis;full;auto@%g,298.15K%@fnx;);vis;full@%%@sbx@%%@mx@% = −(88.8 ± 1.8) kJ·mol^-1. Auxiliary data for tert-butyl benzyl ether (energy of combustion, vapor pressures, and enthalpy of vaporization) were measured using calorimetry and transpiration method.

The chemical equilibrium of the reactive systems (alkanol + methylbutenes  alkyl tert-amyl ether) with the following alkyl substituents:  ethyl, propyl, butyl, iso-propyl, sec-butyl, and cyclohexyl, were studied in the liquid phase. Reactions were investigated in the screwed vials in the temperature range (298 to 393) K, and a cation exchanger Amberlist 15 was used as heterogeneous catalyst. Enthalpies of reactions %@mt;sys@%Δ%@sb@%r%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of tert-amyl alkyl ethers synthesis in the liquid phase were obtained from the temperature dependence of the equilibrium constants and used to derive standard enthalpies of formation, %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@/hd@%%@fn;(;vis;full;auto@%l%@fnx;);vis;full@%%@/hd@%%@mx@% , of tert-amyl alkyl ethers. For the sake of comparison, these enthalpies of formation have been calculated using improved Benson's increments. Calculated values are in close agreement with those from thermochemical measurements.

Vapor pressures and standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% were determined for five cyclohexyl esters:  cyclohexyl formate, cyclohexyl acetate, cyclohexyl propanoate, cyclohexyl butyrate, and cyclohexyl valerate. The data were obtained from the temperature dependence of the vapor pressure measured by the Knudsen and the transpiration methods. Additionally, the standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of the same cyclohexyl esters were measured calorimetrically. An analysis of the results obtained from three independent methods has allowed us to improve the determination of the enthalpies of vaporization by the Knudsen effusion method.

The standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%%@ital@%°%@rsf@%%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of 11 branched tert-butyl alkyl ethers, tert-amyl alkyl ethers, and tert-octyl alkyl ethers have been determined from the temperature dependence of the vapor pressure measured by the transpiration method. The temperature dependences of retention indices for a set of 31 ethers with branched molecular structures were measured using a nonpolar gas chromatographic column. Values of %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%%@ital@%°%@rsf@%%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% for 13 ethers obtained from the transpiration method in this work (as well as some values selected from the literature) together with data for these ethers obtained from the correlation gas-chromatography method were used to derive a correlation for the prediction of the standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%%@ital@%°%@rsf@%%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% for branched ethers at the temperature T = 298.15 K. Experimental values of %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%%@ital@%°%@rsf@%%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% for 19 branched ethers were obtained with the help of this correlation. The procedure of the correlation gas-chromatography method was modified and substantially simplified by introduction of the Kovat's index for the correlation of the retention indices with the experimental %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%%@ital@%°%@rsf@%%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% .

Molar enthalpies of vaporization %@mt;sys@%Δ%@mh;1q@%%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%°%@mh;-3q@%%@sb@%m%@sbx@%%@mx@% of seven benzyl halides and seven benzyl ethers have been obtained from the temperature dependence of the vapor pressure measured by the transpiration method. These values and the correlation-gas chromatography method, based on Kovat's index, have been applied for the determination of %@mt;sys@%Δ%@mh;1q@%%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%°%@mh;-3q@%%@sb@%m%@sbx@%%@mx@% of three cumyl halides (Cl, Br, and I). The data obtained for %@mt;sys@%Δ%@mh;1q@%%@sx@%l%@be@%g%@sxx@%%@ital@%H%@rsf@%°%@mh;-3q@%%@sb@%m%@sbx@%%@mx@% of benzyl derivatives have been checked successfully for internal consistency using enthalpies of formation of alkyl halides and alkyl ethers available from the literature.

The energetics of the C−Cl bond in 2-chloropropionic acid was investigated by using a combination of experimental and theoretical methods. The standard molar enthalpy of formation of liquid (S)-(−)-2-chloropropionic acid, at 298.15 K, was determined as Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (C3H5O2Cl, l) = −(534.6 ± 1.1) kJ·mol^-1, by rotating-bomb combustion calorimetry. The corresponding enthalpy of vaporization, Δvap%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (C3H5O2Cl) = (64.9 ± 0.5) kJ·mol^-1, was also obtained from vapor pressure versus temperature measurements by the transpiration method, leading to Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (C3H5O2Cl, g) = −(469.7 ± 1.2) kJ·mol^-1. This value, together with the enthalpy of the isodesmic and isogyric gas-phase reaction CH3CH(X)COOH(g) + C2H5(g) → CH3CHCOOH(g) + C2H5X(g) (X = H, Cl) predicted by density functional theory calculations and other auxiliary data, was used to derive the enthalpy of formation of the gaseous 1-carboxyethyl radical as Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% [CH(CH3)COOH, g] = −(293 ± 3) kJ·mol^-1, from which DH°[H−CH(CH3)COOH] = 380.7 ± 3.9 kJ·mol^-1 and DH°[Cl−CH(CH3)COOH] = 298.0 ± 3.2 kJ·mol^-1 were obtained. These values are compared with the corresponding C−H and C−Cl bond dissociation enthalpies in XCH2COOH, XCH3, XC2H5, XCH2Cl, XCH(CH3)Cl, XCH&dbd;CH2, and XC6H5 (X = H, Cl). The order DH°(C−H) > DH°(C−Cl) is observed for the carboxylic acids and all other RX compounds. Comparison of DH°[X−CH(CH3)COOH] and DH°[X−CH2COOH] (X = H, Cl) indicates that the replacement of a hydrogen of the CH2 group of XCH2COOH by a methyl group leads to a decrease of both the C−H and C−Cl bond dissociation enthalpy. It is finally concluded that the major qualitative trends exhibited by the C−Cl bond dissociation enthalpies for the series of compounds addressed in this work can be predicted based on Pauling's electrostatic−covalent model.

This work was undertaken for the evaluation and revision of group-additivity values necessary for predicting standard enthalpies of formation and enthalpies of vaporization of ethers, acetals, ketals, and ortho esters by means of Benson's group-additivity methodology. The database on the standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%%@mv;-1q@%g%@mvx@%%@sxx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% has been extended with measurements on several acetals, ketals, and ortho esters using the transpiration method. The standard molar enthalpies of formation %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@/hd@%%@fn;(;vis;full;auto@%[S_EL2;quad]\ g,298.15K%@fnx;);vis;full@%%@/hd@%%@mx@% of alkyl ethers, acetals, ketals, and ortho esters were derived using the data for the %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@/hd@%%@fn;(;vis;full;auto@%[S_EL2;quad]\ l or cr,298.15K%@fnx;);vis;full@%%@/hd@%%@mx@% from the literature and the present results for the enthalpies of vaporization or sublimation. The current database of experimental data for enthalpies of formation and enthalpies of vaporization at 298.15 K have been used to reevaluate the values of the Benson's increments for of alkyl ethers, acetals, ketals, and ortho esters. The group-additivity parameters and strain corrections useful in the application of the Benson's correlation are presented in tabular form, together with a description of their evaluation.

Activity coefficients at infinite dilution %@mt;sys@%γ%@sx@%%@ital@%i%@rsf@%%@be@%∞%@sxx@%%@mx@% of alkanes, alkenes, and alkylbenzenes as well as of the linear and branched C1−C6 alcohols, acetone, acetonitrile, ethyl acetate, alkyl ethers, and chloromethanes in the ionic liquids 1-methyl-3-ethyl-imidazolium bis(trifluoromethyl-sulfonyl) amide and 1,2-dimethyl-3-ethyl-imidazolium bis(trifluoromethyl-sulfonyl) amide were determined by gas chromatography using the ionic liquids as the stationary phase. The measurements were carried out at different temperatures between 313 K and 363 K. From the temperature dependence of the limiting activity coefficients partial molar excess enthalpies at infinite dilution %@mt;sys@%%@ital@%H%@rsf@%%@sx@%%@ital@%i%@rsf@%%@be@%E,∞%@sxx@%%@mx@% of the solutes in the ionic liquids have been derived.

The standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@% %@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of the 14 branched C5 and C6 alkanols 2,2-dimethyl-1-propanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 2-ethyl-1-butanol, 3,3-dimethyl-1-butanol, 2-hexanol, 3-hexanol, 3-methyl-2-pentanol, 4-methyl-2-pentanol, 2-methyl-3-pentanol, 3,3-dimethyl-2-butanol, 2-methyl-2-butanol, 3-methyl-3-pentanol, and 2,3-dimethyl-2-butanol have been determined. The data were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. A linear correlation of enthalpies of vaporization of the secondary alcohols with the number of C atoms has been found. The effect of self-association of aliphatic alcohols in the liquid phase is discussed in terms of the difference of %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@% %@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (298.15 K) between associating alcohols and their nonassociating alkane homomorphs.

Activity coefficients at infinite dilution γi^∞ of 19 alkanes, alkenes, and alkylbenzenes in the ionic liquid 4-methyl-n-butylpyridinium tetrafluoroborate (C10H16BF4N) were determined by gas chromatography using the ionic liquid as stationary phase. The measurements were carried out at different temperatures between 313.1 K and 363.1 K. From the temperature dependence of the limiting activity coefficients partial molar excess enthalpies at infinite dilution %@mt;sys@%%@ital@%H%@rsf@%%@sx@%%@ital@%i%@rsf@%%@be@%E,∞%@sxx@%%@mx@% of the organic solutes in the ionic liquids have been derived.

The chemical equilibrium of the reactive system alkanol + styrene  (1-alkoxyethyl)benzene (where alkyl is methyl, ethyl, propyl, and butyl) was studied in the liquid phase in the temperature range (343 to 423) K using a cation exchanger as the heterogeneous catalyst. Enthalpies of reactions Δr%@mt;sys@%%@ital@%H%@rsf@%%@sx@%m%@be@%o%@sxx@%%@mx@% of (1-alkoxyethyl)benzene synthesis in the liquid phase were obtained from the temperature dependence of equilibrium constants measured in the reactive mixtures with an excess of alkanol and showed a good agreement with those reaction enthalpies derived from values of the enthalpies of formation Δf%@mt;sys@%%@ital@%H%@rsf@%%@sx@%m%@be@%o%@sxx@%%@mx@% (l) of the reactions participants measured for (1-methoxyethyl)benzene and (1-butoxyethyl)benzene by combustion calorimetry. The standard molar enthalpies of vaporization of (1-alkoxyethyl)benzenes were obtained from the temperature dependence of the vapor pressure measured by using the transpiration method. Resulting values of Δf%@mt;sys@%%@ital@%H%@rsf@%%@sx@%m%@be@%o%@sxx@%%@mx@% (g) were used to prove the consistency of the experimental data and to derive strain enthalpies of (1-alkoxyethyl)benzenes. The strain effects were discussed in terms of deviations of Δf%@mt;sys@%%@ital@%H%@rsf@%%@sx@%m%@be@%o%@sxx@%%@mx@% (g) from the group additivity rules.

The chemical equilibrium of the reactive systems n-alkanol + α-methylstyrene  alkyl cumyl ether (alkyl is ethyl, propyl, and butyl) was studied in the liquid phase in the temperature range (300 to 383) K using a cation exchanger as heterogeneous catalyst. Equilibrium ratios Kx obtained from concentrations of the reaction participants in the mixtures with an excess amount of alkanol are practically independent of the reactive mixture composition and can be identified with the thermodynamic equilibrium constant Ka. Enthalpies of reactions %@mt;sys@%Δ%@sb@%r%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of alkyl cumyl ether synthesis in the liquid phase were obtained from the temperature dependence of Ka and showed a good agreement with those reaction enthalpies derived from the values %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@/hd@%%@fn;(;vis;full;auto@%l%@fnx;);vis;full@%%@/hd@%%@mx@% of the reactions participants measured for alkyl cumyl ethers by combustion calorimetry. The standard molar enthalpies of vaporization of alkyl cumyl ethers were obtained from the temperature dependence of the vapor pressure measured by using the transpiration method. Resulting values of %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@/hd@%%@fn;(;vis;full;auto@%g%@fnx;);vis;full@%%@/hd@%%@mx@% were used to prove the consistency of the experimental data and to derive strain enthalpies of alkyl cumyl ethers. The strain effects were discussed in terms of deviations of %@mt;sys@%Δ%@sb@%f%@sbx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@/hd@%%@fn;(;vis;full;auto@%g%@fnx;);vis;full@%%@/hd@%%@mx@% from the group additivity rules.

Chemical equilibria of reactions of transalkylation among tert-butylphenols and tert-butylcatechols in the liquid phase were investigated in the temperature range 373−483 K. The molar enthalpies of fusion %@mt;sys@%Δ%@sx@%cr%@be@%l%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of the catechol, 4-tert-butylcatechol, and 3,5-di-tert-butylcatechol were measured by DSC. The standard (p° = 0.1 MPa) molar enthalpies of formation Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (cr) at the temperature T = 298.15 K were measured by means of combustion calorimetry for 4-tert-butylcatechol and 3,5-di-tert-butylcatechol. The standard molar enthalpies of sublimation of these compounds, and also the enthalpy of vaporization of 3-tert-butylcatechol, were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. The measured reaction enthalpies were utilized for reconciliation of calorimetrically derived standard molar enthalpies of formation of tert-butyl-substituted phenols and catechols, as a stringent test of thermodynamic consistency of results derived from the diverse techniques employed in this work. Resulting values of Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (g) of tert-butylcatechols were obtained at the temperature T = 298.15 K and used to derive their strain enthalpies. The intramolecular interactions of the substituents were discussed in terms of deviations of Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (g) from the group additivity rules. No peculiarities in the interaction energy among alkyl groups and the hydroxyl groups in the ortho-, para-, and meta-positions of alkylcatechols in comparison with those of alkyl-substituted phenols were detected. Thus, no new parameters are needed for the prediction of the Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (g) values of alkylcatechols by using the group-additive procedure.

The standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% or sublimation %@mt;sys@%Δ%@sx@%cr%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of 2-methylpropanoic, butanoic, 2-methylbutanoic, 3-methylbutanoic, pentanoic, 2,2-dimethylpropanoic, 3,3-dimethylbutanoic, hexanoic, heptanoic, and octanoic acids were measured by the transpiration method. The enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of ethanoic, propanoic, 2-methylpropanoic, and butanoic acids were measured using correlation gas chromatography. The enthalpies of the phase transitions of 2,2-dimethylpropanoic acid were measured using differential scanning calorimetry. The values of %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% of the compounds studied were taken as a basis for the development of a group-additivity predictive scheme. The standard molar enthalpies of formation Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (g) at the temperature T = 298.15 K of monocarboxylic acids were derived using the data for Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (l or cr) from the literature and the present results for the enthalpies of vaporization or sublimation. The improved group-contribution method was used for the estimation of the gaseous enthalpies of formation of monocarboxylic acids.

The standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%°%@sx@%m%@be@%%@sxx@%%@mx@% of 1-methylcyclohexene, 4-methylcyclohexene, 2,4-dimethyl-2-pentene, cis-2-heptene, trans-4-octene, 1-nonene, 2,6-dimethylheptene, 1-undecene, trans-2,2,4,6,6-pentamethyl-3-heptene, and cis-2,2,4,6,6-pentamethyl-3-heptene at the temperature T = 298.15 K were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. The values of %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%°%@sx@%m%@be@%%@sxx@%%@mx@% (298.15 K) for these compounds and additionally for 3-methylcyclohexene were also measured using the correlation gas-chromatography method. The results from both methods are indistinguishable within the experimental uncertainties of less than ±0.5 kJ·mol^-1. Results from this work together with the data available from the literature were used to derive correlations for the prediction of the standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%°%@sx@%m%@be@%%@sxx@%%@mx@% (298.15 K) of monoolefins with linear and branched hydrocarbon chains.

This work has been undertaken for the evaluation and revision of group additivity values necessary for predicting gaseous standard enthalpies of formation of nitrogen and oxygen containing compounds by means of Benson's group additivity methodology. The current database of experimental data for enthalpies of formation, enthalpies of vaporization and enthalpies of sublimation was used to derive the values of the strain-free increments for imines, amides, oxo-amides, and carboxylic acids anhydrides. The group-additivity parameters and strain corrections useful in the application of the Benson correlation are presented in tabular form, together with a description of their evaluation and comments on their reliability.

The temperature dependencies of retention indices of a set of 80 esters with branched molecular structures were measured on a nonpolar gas chromatographic column. The correlation gas chromatography method and reliable data set of 16 esters selected from the literature were used to derive a correlation for the prediction of the standard molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% at the temperature T = 298.15 K. Experimental values of %@mt;sys@%Δ%@sx@%l%@be@%g%@sxx@%%@mx@% %@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% for 64 branched esters were obtained with the help of this correlation. The vaporization enthalpies of isopentyl acetate, ethyl hexanoate, and neopentyl pivalate were additionally obtained by the transiration method from the temperature dependence of the vapor pressure measured in a flow system and used for checking the validity of the correlation gas chromatography method.

The standard (p° = 0.1 MPa) molar enthalpies of formation ΔfH°m(l) at T = 298.15 K of N,N-dimethylbenzylamine, α-methylbenzylamine, and α,α-dimethylbenzylamine were determined by means of combustion calorimetry. The standard molar enthalpies of vaporization of these compounds and also of benzylamine, benzyl alcohol, and α,α-dimethylbenzyl alcohol were obtained from the temperature dependence of the vapor pressure measured in a flow system. Resulting values of ΔfH°m(g) were obtained at T = 298.15 K and used to derive strain enthalpies of benzyl derivatives. The intramolecular interactions of the substituents were discussed in terms of deviations of ΔfH°m(g) from the group additivity rules. These values provide a further improvement on the group-contribution methodology for estimation of the thermodynamic properties of organic compounds.

The standard (p° = 0.1 MPa) molar enthalpies of sublimation %@mt;sys@%Δ%@sx@%cr%@be@%g%@sxx@%%@mx@% Hm° at the temperature T = 298.15 K for 1,1,2-triphenylethane, triphenylmethane, 1,1,1-triphenylethane, 1,1,1-triphenylbutane, and tetraphenylmethane were obtained from the temperature function of the vapor pressure measured in a flow system. Standard molar enthalpy of formation ΔfHm°(cr) at the temperature T = 298.15 K was measured using combustion calorimetry for 1,1,1-triphenylbutane. Enthalpies of fusion of all compounds were measured by differential scanning calorimetry. These experimental results together with the data available from the literature were used for the estimation of strain enthalpies of phenyl substituted alkanes and for the improvement of group-contribution methodology.

The standard (p° = 0.1 MPa) molar enthalpies of vaporization %@mt;sys@%Δ%@sx@%1%@be@%g%@sxx@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% at the temperature T = 298.15 K for diphenylmethane, (4-methylphenyl)phenylmethane, 1,1-diphenylethane, 1,1-bis(4-methylphenyl)ethane, 2-methyl-1,1-diphenylpropane, 1,1-diphenylpropane, and 1,1-diphenylbutane were obtained from the temperature dependence function of vapor pressure measured in a flow system. Standard molar enthalpies of formation Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (l) at the temperature T = 298.15 K were measured using combustion calorimetry for 1,1-diphenylethane and 2-methyl-1,1-diphenylpropane. These experimental results together with the data available from the literature were used for the calculation of strain enthalpies of diphenylalkanes using the group-contribution procedure. The estimated strain enthalpies of the compounds studied were negligible within the boundaries of experimental uncertainties of about 1−2 kJ·mol^-1. Thus no new strain corrections are needed for the prediction of the Δf%@mt;sys@%%@ital@%H%@rsf@%%@/xs;55;%lnwidth@%°%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@sb@%m%@sbx@%%@mx@% (g) of similarly shaped molecules by using group-additivity procedures.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Standard enthalpies of formation are obtained for the geminal esters (I) and (II) and the reference compounds (III) and (IV) from their combustion and vaporization enthalpies.