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The present work reports an experimental thermodynamic study of two nitrogen heterocyclic organic compounds, fenclorim and clopyralid, that have been used as herbicides. The sublimation vapor pressures of fenclorim (4,6-dichloro-2-phenylpyrimidine) and of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) were measured, at different temperatures, using a Knudsen mass-loss effusion technique. The vapor pressures of both crystalline and liquid (including supercooled liquid) phases of fenclorim were also determined using a static method based on capacitance diaphragm manometers. The experimental results enabled accurate determination of the standard molar enthalpies, entropies and Gibbs energies of sublimation for both compounds and of vaporization for fenclorim, allowing a phase diagram representation of the (p,T) results, in the neighborhood of the triple point of this compound. The temperatures and molar enthalpies of fusion of the two compounds studied were determined using differential scanning calorimetry. The standard isobaric molar heat capacities of the two crystalline compounds were determined at 298.15 K, using drop calorimetry. The gas phase thermodynamic properties of the two compounds were estimated through ab initio calculations, at the G3(MP2)//B3LYP level, and their thermodynamic stability was evaluated in the gaseous and crystalline phases, considering the calculated values of the standard Gibbs energies of formation, at 298.15 K. All these data, together with other physical and chemical properties, will be useful to predict the mobility and environmental distribution of these two compounds.

Tropical storms produce competent self-regenerating coral fragments capable of originating new coral colonies. These climatic events are predicted to increase in the future due to ocean warming, the main cause of coral bleaching. Estimated increases in precipitation will affect salinity at shallow reef areas which combined with ocean warming will aggravate the effects of coral bleaching. In this study the long-term effects of increased temperature (30 °C), low salinity (20 psu) and the combination of these stressors were investigated and compared to the control treatment (26 °C, 33 psu). Mortality, condition, growth, and regeneration ability of nine Indo-Pacific reef-forming coral species were assessed, for 60 days. The coral colonies used were kept in captivity for several years, providing information on their thermal and salinity history. Twenty replicate fragments were cut from each coral species’ colony, weighed and glued to the top of a numbered expansion anchor and then acclimated to the experimental aquarium. Half of these fragments was inflicted with one circular injury in order to test its effects on mortality, condition, and growth rate and also to estimate tissue regeneration rates. The results showed that mortality rate was highest in the high temperature + low salinity treatment, reaching 100% for seven out of the nine coral species, in the first six days of experiment, 100% for Psammocora contigua on the 40th day and 75% for Galaxea fascicularis on the 60th day of experiment. Partial mortality was lowest for P. contigua and G. fascicularis in the low salinity treatment. These two coral species also presented the best coral condition. Coral fragments growth rates decreased as temperature increased and salinity decreased except for G. fascicularis fragments that showed similar growth rates at 26 °C and 30 °C for both salinities. Regeneration rates increased with temperature being highest in the high temperature treatment and lowest at 20 psu. It was concluded that G. fascicularis and P. contigua are the most resilient to low salinity. G. fascicularis fragments were the only ones that withstood the synergistic effects of high temperature and low salinity and are likely to become dominant through asexual reproduction in the Indo-Pacific coral reefs in a warmer ocean, especially in coastal areas prone to low salinity episodes.

This work presents an extended study of the thermal behavior of the alkyl and dialkylpyridinium derivatives of the bis(trifluoromethylsulfonyl)imide ionic liquid series, using high resolution power...

Background Mood disorders, as depression and anxiety, are frequent in Multiple Sclerosis (MS) patients. High pro-inflammatory cytokine levels (e.g. IL-1β) have been reported in depressed individuals. Objective We aimed to investigate the role of the rs16944 (IL-1β-511 C>T) polymorphism in the development of anxiety and depression symptoms in a Portuguese cohort of MS patients. Methods 393 MS patients answered the Hospital Anxiety and Depression Scale (HADS) at T1. This questionnaire was reapplied to a subgroup of 175 MS patients approximately three years later (T2). HADS cut-off scores for anxiety and depression were respectively ≥11 and ≥8. Results At T1, anxiety was found in 106 MS patients (27.0%) and 11 controls (16.7%); whereas depression was identified in 116 (29.5%) MS patients and 9 controls (13.6%). Persistent anxiety and depression were respectively recorded in 12% and 20% of MS patients. The rs16944TT genotype was found to be a susceptibility factor for the occurrence of depression at T1 (OR = 3.16, p=0.002) and the development of persistent depression (OR = 5.63, p=0.003) in MS. Conclusion Study results support the hypothesis that inflammation is a significant factor in psychopathology development.

The principle of operation, concepts and recent developments of the Knudsen effusion methodology for the vapour pressure measurement of ionic liquids and other low volatile liquids and solids are presented. A new version of a Knudsen effusion apparatus, coupled with a quartz crystal microbalance, which is used for a reliable measurement of the mass flow from a Knudsen effusion cell, is described in detail. In the new system, designed and optimized for the vapour pressure measurement of ionic liquids, it is possible to measure the vapour pressure of small samples using very short effusion time over a wide temperature range. This apparatus allows the vapour pressure measurements using step-temperature and continuous-temperature modes that have the advantage of reducing the measurement time interval and minimize the effect of a sample degradation. A significant number of improvements on the performance and capability for the vapour pressure measurements of ionic liquids has been implemented: in situ temperature control of the vacuum chamber for a better stability of background signal; a new design of a stainless steel effusion cell to decrease the reactivity and sample decomposition; dual temperature control ensuring a positive temperature gradient between bottom and top of the cell in order to avoid the ionic liquids condensation on the effusion cell lid and significantly improved stability of the time frequency derivative at high temperatures; Installation and test of a mass flow tube, on the top of the outlet of the cell lid oven block in order to increase the mass sensitivity coefficient of QCM. The tests and benchmarking concerning the measurement of vapour pressures of ionic liquids performed with [C2mim][NTf2] indicate that the described Knudsen effusion apparatus and methodology is able to produce reproducible and reliable experimental vapour pressure data with an accuracy and quality similar than the achieved in the measurements with low volatile solids. The effect of the improvements on the performance of the Knudsen effusion apparatus was tested and evaluated by the comparison of the vapour pressure results of 1,3,5-triphenylbenzene and 1-ethyl-3-methylimidazolium with the available literature data.

Spent coffee grounds (SCGs) are a waste product with no relevant commercial value. However, SCGs are rich in extractable compounds with biological activity. To add value to this coffee byproduct, water and aqueous solutions of cholinium-based ionic liquids (ILs) were studied to extract caffeine from SCGs. In general, all IL aqueous solutions lead to higher extraction efficiencies of caffeine than pure water, with aqueous solutions of cholinium bicarbonate being the most efficient. A factorial planning was applied to optimize operational conditions. Aqueous solutions of cholinium bicarbonate, at a temperature of 80 °C for 30 min of extraction, a biomass–solvent weight ratio of 0.05 and at an IL concentration of 1.5 M, made it possible to extract 3.29 wt% of caffeine (against 1.50 wt% obtained at the best conditions obtained with pure water). Furthermore, to improve the sustainability of the process, the same IL aqueous solution was consecutively applied to extract caffeine from six samples of fresh biomass, where an increase in the extraction yield from 3.29 to 13.10 wt% was achieved. Finally, the cholinium bicarbonate was converted to cholinium chloride by titration with hydrochloric acid envisioning the direct application of the IL-caffeine extract in food, cosmetic and nutraceutical products. The results obtained prove that aqueous solutions of cholinium-based ILs are improved solvents for the extraction of caffeine from SCGs, paving the way for their use in the valorization of other waste rich in high-value compounds.

A series of pyridyl analogues of rosamines was prepared by employing two methodologies: (i) the conventional-heating condensation of a pyridinecarboxaldehyde with 3-(diethylamino)phenol in propionic acid, and (ii) the novel ohmic-heating assisted condensation under "on water" conditions, followed by oxidation. The 4-pyridyl substituted rosamine was further converted into the N-methylpyridinium derivative through N-alkylation using methyl iodide. The influence of the position and cationization of the nitrogen atom of the pyridyl ring in the physicochemical properties of fluorophores was investigated by 1 H, 13 C, 15 N NMR spectral analysis, UV/Vis and fluorescence spectroscopy, single-crystal X-ray diffraction (4-pyridyl and N-methylpyridinium derivatives) and thermal-behavior analysis. Curiously, for ethanolic solutions of 4-pyridyl and N-methylpyridinium derivatives an extinction of color and fluorescence over time was observed. This phenomenon was further studied and the data revealed that it is the result of nucleophilic addition of ethoxide ion to the central 9-position of the xanthene. The kinetics of the process is slower for the 4-pyridyl rosamine, which emphasizes the importance of the charge in the N-methylpyridinium analogue in the reactivity of the molecule towards a nucleophile agent. This phenomenon is reversible, meaning that the compounds can be rapidly recovered by decreasing the pH, opening new avenues in the sensing applications of this class of rosamines.

International audience; Global warming is leading to increases in tropical storms ́frequency and intensity, allowing fragmentation of reef-forming coral species, but also to coral bleaching and mortality. The first level of organismś response to an environmental perturbation occurs at the cellular level. This study investigated the long-term oxidative stress on fragments of nine Indo-Pacific reef-forming coral species exposed for 60 days to increasing temperatures (30 °C and 32 °C) and compared results with control temperature (26 °C). Coral overall condition (appearance), lipid peroxidation (LPO), catalase activity (CAT), and glutathione S-transferase (GST) were assessed. The species Turbinaria reniformis, Galaxea fascicularis, and Psammocora contigua were the most resistant to heat stress, presenting no oxidative damage at 30 °C. Unlike G. fasciularis, both T. reniformis and P. contigua showed no evidence of oxidative damage at 32 °C. All remaining species ́fragments died at 32 °C. Stylophora pistillata and Pocillopora damicornis were the most susceptible species to heat stress, not resisting at 30 °C.

Twelve surface-active ionic liquids (SAILs) and surface-active derivatives, based on imidazolium, ammonium, and phosphonium cations and containing one, or more, long alkyl chains in the cation and/or the anion, were synthetized and characterized. The aggregation behavior of these SAILs in water, as well as their adsorption at solution/air interface, were studied by assessing surface tension and conductivity. The CMC values obtained (0.03-6.0 mM) show a high propensity of these compounds to self-aggregate in aqueous media. Their thermal properties were also characterized, namely the melting point and decomposition temperature by using DSC and TGA, respectively. Furthermore, the toxicity of these SAILs was evaluated using the marine bacteria Aliivibrio fischeri (Gram-negative). According to the EC50 values obtained (0.3-2.7 mg L-1 ), the surface-active compounds tested should be considered "toxic" or "highly toxic". Their ability to induce cell disruption of Escherichia coli cells (also Gram-negative), releasing the intracellular green fluorescent protein (GFP) produced, was investigated. The results clearly evidence the capability of these SAILs to act as cell disruption agents. published

Background: Genetic Generalized Epilepsies (GGEs) are a heterogeneous group of syndromes characterized by generalized seizure activity that affects both hemispheres, with mainly genetic causes. Neuroinflammation has been established as an important mechanism in epileptogenesis. The ability to develop an appropriated immune response is strongly determined by immunogenetic factors. In this setting, our aim was to evaluate potential associations between GGEs and immunogenetic factors. Methods: The rs16944 (IL-1β -511 T > C) polymorphism and the HLA-DRB1 locus were genotyped in a Portuguese GGE population. Association with two clinicopathological features, photosensitivity and refractoriness, was investigated. This case-control study included 323 GGE patients (187 F, 136 M, 34.0 ± 13.9 years of age), 145 of which with JME diagnosis (88 F, 57 M, 34.1 ± 14.0 years), and 282 healthy controls (174 F, 108 M, 37.7 ± 11.6 years). Results: Decreased frequencies of the HLA-DRB1*09 and DRB1*13 alleles were observed in the GGE population. HLA-DRB1*07 frequency was increased in JME. Rs16944 allelic frequencies were similar between patients and controls. Conclusions: These results, not entirely consistent with previous reports, suggest that HLA molecules may have a complex role in epileptogenesis. Highlights: HLA-DRB1*09 and HLA-DRB1*13 alleles are protective factors for GGE; HLA-DRB1*07 allele is a susceptibility factor for JME; HLA molecules may have a complex role in epileptogenesis. This research was partially funded by a BICE Tecnifar Grant. The funders had no role in study design, data collection and analysis or preparation of the manuscript. Ricardo Martins-Ferreira is funded by Doctoral fellowship SFRH/ BD/137900/2018 from Fundação para a Ciência e Tecnologia (FCT). info:eu-repo/semantics/publishedVersion

UID/MAR/04292/2019 UID/Multi/04378/2019 SFRH/BD/103047/2014 Global warming is one of the major causes of reef coral ecosystems’ degradation. Predictions of further rise in sea surface temperatures call for urgent action. In this study, a holistic method for bio-monitoring heat stress in reef ecosystems was tested and optimized. Long-term induction of antioxidant enzymes and oxidative stress by elevated temperatures (30 °C and 32 °C) was assessed on fragments of reef-building corals and compared to control conditions (26 °C). The quantification of both oxidative stress, through lipid peroxidation (LPO) levels, and antioxidant enzyme activities: superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) in a long-term experiment (60 days), using seven Indo-Pacific reef-building coral species, provided useful information that was interpreted in combination with the observed partial mortality and growth rate of these organisms. These biomarkers were combined in integrated biomarker response (IBR) indices, either in an antioxidant defense mechanisms and oxidative stress response category (approach A: GST, CAT, LPO, and SOD) or in an integrated stress response category – organism performance (approach B: GST, CAT, LPO, SOD, partial mortality, and growth rate). The results of this study indicate that the IBRs were responsive to temperature treatment and dependent on the coral species. The approach B was the most adequate since it better reflected the stress suffered by the tested species, whereas the set of four biochemical biomarkers (approach A) was not enough to explain the organismal response of most of the tested species to thermal stress conditions. publishersversion published

The study of the phase behaviour of binary mixtures of fatty acid methyl esters (FAME) and alkanes are here studied to understand the behaviour of the mineral diesel/biodiesel blends. Six binary mixtures of the most common saturated methyl esters (methyl stearate or methyl palmitate) with a saturated alkane (hexadecane, octadecane or eicosane) were evaluated by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and optical microscopy. The binary mixtures studied show a more complex phase behaviour than previously reported, which it is shown to be dependent of the size difference between the alkyl chain length of the esters and the alkanes. It was found that in mixtures with equal alkyl chain length a co-crystal is formed, and when the alkane chain length is larger than in the FAME by two methylene groups the formation of a solid-solution increasing significantly the solid phase stability is observed. The results and conclusions derived from the phase behaviour of this set of binary mixtures, between alkanes and methyl esters, can be used as a model for the interpretation of the cloud and pour points increase in biodiesel blends (in special the ones with a rich fraction of methyl palmitate or methyl stearate when combined with mineral diesel with high content of octadecane or eicosane respectively).

International audience; Global warming is leading to both increases in frequency and intensity of tropical storms, with consequent salinity decrease at shallow reef areas, but also to mass bleaching events and mortality of reef-building corals around the world. Tropical storms can help reef-building corals to reproduce through fragmentation, allowing their expansion throughout the reefs. The combination of high temperature and low salinity may aggravate the effects of coral bleaching. Investigation of alterations at the cellular level will be useful since this is the first detectable response of organisms to changes in environmental conditions. In this study, the long-term oxidative stress induced by elevated temperature (30 °C), low salinity (20 psu), and their combination was studied on fragments of reef-forming corals, and compared to control conditions (26 °C, 33 psu). Determination of oxidative stress biomarkers: lipid peroxidation (LPO); superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) activities in a long-term experiment (60 days), using nine Indo-Pacific reef-forming coral species, provided useful information that was interpreted in combination with the observed general condition of these organisms (appearance: normal, pale, bleached, dead). High temperature affected the general condition of the species tested to a lower degree than did low salinity. Only two species died at high temperature, while low salinity resulted in the death of all species with the exception of two (P. contigua and G. fascicularis). Oxidative damage was detected in some species, as were antioxidant responses, at high temperature. Coral general condition was severely affected in all species in the low salinity treatment. Galaxea fascicularis and Psammocora contigua were the most resistant to salinity stress, having survived the experimental treatment. Oxidative damage was not detected in these species, but there was an antioxidant response. The high temperature + low salinity (HT + LS) treatment had synergistic effects in the condition of all species. Galaxea fascicularis was the only survivor in the HT + LS treatment. Mortality was high (60%) for this species, oxidative damage was not detected, but an increase in SOD activity revealed an antioxidant response.

Thermochemical and thermodynamic properties of 2-, 3- and 4-iodonitrobenzene have been determined using a combination of calorimetric and effusion techniques as well as computational calculations. The standard (p° = 0.1 MPa) molar enthalpies of formation, in the crystalline state, Δ f H m ∘ (cr) , at T = 298.15 K, were derived from the standard molar enthalpies of combustion, Δ c H m ∘ (cr) , in oxygen, to yield CO2(g), N2(g), and I2(cr), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of these compounds, Δ cr g H m ∘ , at T = 298.15 K, were determined using high temperature Calvet microcalorimetry. The Knudsen mass-loss effusion technique was used to determine the standard molar enthalpies, entropies and Gibbs free energies of sublimation, at T = 298.15 K, of the three studied compounds. The combination of some of the referred thermodynamic parameters yielded the standard (po = 0.1 MPa) molar enthalpies of formation in the gaseous phase, at T = 298.15 K, of the three isomers: Δ f H m ∘ ( 2 - iodonitrobenzene, g ) = (178.8 ± 1.5) kJ · mol - 1 , Δ f H m ∘ ( 3 - iodonitrobenzene, g ) = (155.4 ± 1.8) kJ · mol - 1 and Δ f H m ∘ ( 4 - iodonitrobenzene, g ) = (151.8 ± 1.6) kJ · mol - 1 . The results were analyzed and interpreted in terms of enthalpic increments and molecular structure. Using the empirical scheme developed by Cox, the values of the standard molar enthalpies of formation in the gaseous phase were estimated and afterwards compared with the ones obtained experimentally, being both interpreted in terms of the molecular structure of the compounds. For comparison purposes, standard molecular calculations at the B3LYP6-311++G(d, p) level were performed, and the gas-phase enthalpies of formation of the three compounds were estimated; the results are in good agreement with experimental data. Furthermore, the molecular structures of the three molecules were established and the structural parameters were determined at the B3LYP/6-311++G(d, p) level of theory. The computational study was also extended to the determination of proton and electron affinities, basicities, and adiabatic ionization enthalpies.

The thermochemistry of α-D-xylose(cr) was studied by means of oxygen bomb calorimetry and a Physical Property Measurement System (PPMS) in zero magnetic field. The sample of α-D-xylose(cr) used in this study was one well-characterized by HPLC, Karl Fischer analysis, NMR, and by carbon dioxide analysis. The standard molar enthalpy of combustion was found to be Δc H m o = −(2342.2 ± 0.8) kJ·mol−1 at T = 298.15 K and at the standard pressure p° = 0.1 MPa. The standard molar heat capacity for α-D-xylose(cr) was measured with the PPMS over the temperature range 1.9001 ⩽ T/K ⩽ 303.66. At T = 298.15 K, C p ,m o = (178.1 ± 1.8) J·K−1·mol−1. The values of C p ,m o were fit as a function of T by using theoretical and empirical models for appropriate temperature ranges. The results of these fits were used to calculate values of C p ,m o , the entropy increment Δ 0 T S m o , Δ 0 T H m o , and Φ m o = ( Δ 0 T S m o - Δ 0 T H m o / T ) from T = 0.5 K to T = 300 K. Derived quantities for α-D-xylose(cr) are the standard molar enthalpy of formation Δ f H m o = −(1054.5 ± 1.1) kJ·mol−1, the third law standard molar entropy S m o = (175.3 ± 1.9) J·K−1·mol−1, and the standard molar Gibbs energy of formation Δ f G m o = −(750.5 ± 1.0) kJ·mol−1. A comparison of values of Δc H m o and S m o for the five-carbon aldoses demonstrated a striking similarity in the values of these respective properties for α-D-xylose(cr), D-ribose(cr), and D-arabinose(cr). Thermochemical network calculations were performed that led to values of the standard formation properties at T = 298.15 K for a variety of biochemical substances: D-xylose(aq), D-xylose−(aq), D-xylose2−(aq), D-lyxose(cr and aq), D-lyxose−(aq), D-xylulose(aq), xylitol(aq), 1,4-β-D-xylobiose(am and aq), and 1,4-β-D-xylotriose(am and aq).

Densities, viscosities and refractive index, as a function of temperature, and isobaric thermal expansion coefficient, were determined for 1-alkyl-3-methylimidazolium hexafluorophosphate, [C(N - 1)C(1)im]PF6] (where N = 5 to 10) series of ionic liquids. The density presents a regular decrease along the ionic liquid series, with no detectable alkyl chain length dependence of the thermal expansion coefficient. Both the refractive index and viscosity show a trend shift along the series around the [C(6)C(1)im][PF6] that could be associated to the impact of the change in the nanostructuration of the ionic liquids. The experimental results are compared with the analogous [C(N - 1)C(1)im][NTf2] series and the effect of the anion is analyzed. The sphericity of the [PF6](-) anion is reflected in the lower pre-exponential VTF parameter, A(eta), and the higher viscosity of the [C(N - 1)C(1)im][PF6]. when compared with the [C(N - 1)C(1)im][NTf2] series, is ruled by the higher energy barriers, which are related with stronger electrostatic interaction due to the low charge dispersion of the [PF6](-),anion. (C) 2013 Elsevier B.V. All rights reserved.

This report presents a study of the thermodynamic properties of 9-fluorenone and 9-fluorenol. The standard enthalpies of formation of 9-fluorenone and 9-fluorenol in the crystalline phase at T = 298.15 K were determined from the energies of combustion in oxygen as −(11.4 ± 3.8) kJ·mol–1 and −(66.3 ± 2.9) kJ·mol–1, respectively. Vapor pressures of the two compounds were measured at several temperatures using two different experimental methods (Knudsen effusion for crystalline-phase vapor pressures and a static method for crystalline- and liquid-phase vapor pressures), which yielded reliable values of the enthalpies of sublimation, vaporization, and fusion. The sublimation and fusion enthalpies were also determined using calorimetric methods. The enthalpies of sublimation at T = 298.15 K were derived from the static vapor pressure measurements as (95.1 ± 0.5) kJ·mol–1 for 9-fluorenone and (108.3 ± 0.5) kJ·mol–1 for 9-fluorenol. The results enabled the determination of the standard Gibbs energy of the aerobi...

Vapour pressures of both crystalline and liquid (including super-cooled liquid) phases of fluoranthene were measured using a pressure gauge (capacitance diaphragm manometer) over the temperature range (348.8 to 404.3) K yielding accurate determination of enthalpies and entropies of sublimation and vaporisation. Enthalpy of sublimation was also determined using Calvet microcalorimetry. The enthalpy of fusion was derived from vapour pressure results and from d.s.c. experiments. Static bomb calorimetry was used to determine the enthalpy of combustion of fluoranthene from which the standard enthalpy of formation in the crystalline phase was calculated. The enthalpy of formation in the gaseous phase was calculated combining the result derived for the crystalline phase with the enthalpy of sublimation determined from the vapour pressure measurements. Computational results of the enthalpies of formation of fluoranthene and fluorene were also calculated at the G3 and G4 levels, and compared with the experimental values.

The standard ( p ° = 0.1 MPa) molar enthalpies of formation, in the condensed phase, of the three monoiodoanisoles, were derived from the respective enthalpies of combustion, measured by rotating-bomb combustion calorimetry. Their enthalpies of sublimation/vaporization, at T = 298.15 K, were obtained by Calvet microcalorimetry using the high-temperature vacuum sublimation technique. Moreover the standard molar enthalpy, entropy and Gibbs energy of sublimation, at T = 298.15 K, of 4-iodoanisole were derived from the Knudsen mass-loss effusion technique. Combining the former sets of experimental results, the standard molar enthalpies of formation in the gas-phase, at T = 298.15 K, of 2-, 3- and 4-iodoanisole were derived, respectively, as: (15.1 ± 2.1) kJ · mol −1 ; (11.8 ± 2.2) kJ · mol −1 , and (12.4 ± 1.6) kJ · mol −1 . The experimental values of the gas-phase enthalpies of formation of each iodoanisole were also estimated by means of the empirical scheme developed by Cox and by density functional theory calculations employing the B3LYP/6-311++G(d,p) approach. Estimated values are in excellent agreement with the reported experimental ones derived in the present paper.

This work reports new experimental thermodynamic results on fluorene. Vapor pressures of both crystalline and liquid phases were measured using a pressure gauge (capacitance diaphragm manometer) and Knudsen effusion methods over a wide temperature range (292.20 to 412.16) K yielding accurate determination of enthalpy and entropy of sublimation and of vaporization. The enthalpy of sublimation was also determined using Calvet microcalorimetry. The enthalpy of fusion was derived from vapor pressure results and from d.s.c. experiments. Static bomb calorimetry was used to determine the enthalpy of combustion of fluorene from which the standard enthalpy of formation in the crystalline phase was calculated. The enthalpy of formation in the gaseous phase was calculated combining the result derived for the crystalline phase with the enthalpy of sublimation.

This paper reports a combined experimental and computational thermochemical study of 4-benzyloxyphenol. Static bomb combustion calorimetry and Knudsen mass-loss effusion technique were used to determine the standard (p° = 0.1 MPa) molar enthalpy of combustion, Δ c H m ∘ = - ( 6580.1 ± 1.8 ) kJ · mol - 1 , and of sublimation, Δ cr g H m ∘ = ( 131.0 ± 0.9 ) kJ · mol - 1 , respectively, from which the standard (p° = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, at T = 298.15 K, Δ f H m ∘ = - ( 119.5 ± 2.7 ) kJ · mol - 1 were derived. For comparison purposes, the gas-phase enthalpy of formation of this compound was estimated by G3(MP2)//B3LYP calculations, using a set of gas-phase working reactions; the results are in excellent agreement with experimental data. G3(MP2)//B3LYP computations were also extended to the calculation of the gas-phase enthalpies of formation of the 2- and 3-benzyloxyphenol isomers. Furthermore, this composite approach was also used to obtain information about the gas-phase acidities, gas-phase basicities, proton and electron affinities, adiabatic ionization enthalpies and, finally, O–H bond dissociation enthalpies.

The standard (p° = 0.1 MPa) molar enthalpies of formation, in the crystalline state, of the 1- and 2-cyanonaphthalene were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static-bomb combustion calorimetry. Vapor pressure measurements at different temperatures, using the Knudsen mass loss effusion technique, enabled the determination of the enthalpy, entropy, and Gibbs energy of sublimation, at T = 298.15 K, for both isomers. The standard molar enthalpies of sublimation, at T = 298.15 K, for 1- and 2-cyanonaphthalene, were also measured by high-temperature Calvet microcalorimetry. - Δ c U m ∘ ( cr ) / ( kJ · mol - 1 ) Δ f H m ∘ ( cr ) / ( kJ · mol - 1 ) Δ cr g H m ∘ ( cr ) / ( kJ · mol - 1 ) 1-Cyanonaphthalene 5514.4 ± 1.6 188.5 ± 2.2 88.6 ± 0.5 2-Cyanonaphthalene 5510.5 ± 1.7 184.6 ± 2.2 92.1 ± 0.1 Combining these two experimental values, the gas-phase standard molar enthalpies, at T = 298.15 K, were derived and compared with those estimated by employing two different methodologies: one based on the Cox scheme and the other one based on G3MP2B3 calculations. The calculated values show a good agreement with the experimental values obtained in this work.

Case reports are presented for three patients with metastatic breast cancer who received first-line treatment with bevacizumab in combination with taxanes in clinical trials. Two patients showed peak reductions in lesion size of 49 and 70%, respectively. In one patient, subsequent treatment with bevacizumab in combination with capecitabine [Xeloda (after discontinuation of paclitaxel due to asthenia)] yielded peak reductions in target lesion size of 78%. One patient experienced a progression-free survival time of 16 months. In all three patients, bevacizumab was well tolerated and mostly displayed only mild toxicities.

This work reports the standard ( p ° = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, Δ f H m ∘ ( g ) , of 2,4-, 2,6-, and 3,5-dibromophenol, at T = 298.15 K, respectively, as (59.6 ± 2.6) kJ · mol −1 , (49.1 ± 2.2) kJ · mol −1 and (39.5 ± 2.0) kJ · mol −1 . These experimental values were derived from the measurements of the standard molar enthalpies of formation, in the crystalline phase, Δ f H m ∘ ( 2,4-dibromophenol,cr ) = - ( 140.9 ± 2.1 ) kJ · mol - 1 , Δ f H m ∘ ( 2,6-dibromophenol,cr ) = - ( 132.5 ± 1.6 ) kJ · mol - 1 and Δ f H m ∘ ( 3,5-dibromophenol,cr ) = - ( 134.5 ± 1.7 ) kJ · mol - 1 , at the same reference temperature, achieved from the standard molar enthalpies of combustion, in oxygen, to yield CO 2 (g) and HBr·600H 2 O(l), measured by rotating-bomb combustion calorimetry, together with measurements of the standard molar enthalpies of sublimation, at T = 298.15 K, as Δ cr g H m ∘ ( 2,4-dibromophenol ) = ( 81.3 ± 1.5 ) kJ · mol - 1 , Δ cr g H m ∘ ( 2,6-dibromophenol ) = ( 83.4 ± 1.5 ) kJ · mol - 1 and Δ cr g H m ∘ ( 3,5-dibromophenol ) = ( 94.3 ± 1.8 ) kJ · mol - 1 , obtained using the Calvet high temperature vacuum sublimation technique. The standard molar enthalpy of sublimation, at T = 298.15 K, for the 3,5-dibromophenol was also determined from the temperature–vapour pressure dependence, obtained by the Knudsen mass loss effusion method, Δ cr g H m ∘ ( 3,5-dibromophenol ) = ( 95.0 ± 1.1 ) kJ · mol - 1 . For this isomer it is also reported the standard ( p ° = 0.1 MPa) molar entropy and Gibbs energy of sublimation, at T = 298.15 K. The experimental values of the gas-phase enthalpies of formation of each compound were compared with estimates using the empirical scheme developed by Cox and with the calculated values based on density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional at the 6-311++G(d,p) basis set. These two methodologies were also used to estimate the enthalpies of formation in the gas-phase of the 2,3-, 2,5-, and 3,4-dibromophenol.

This work reports the experimental and computational thermochemical study performed on three difluorinated nitrobenzene isomers: 2,4-difluoronitrobenzene (2,4-DFNB), 2,5-difluoronitrobenzene (2,5-DFNB), and 3,4-difluoronitrobenzene (3,4-DFNB). The standard (p° = 0.1 MPa) molar enthalpies of formation in the liquid phase of these compounds were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. A static method was used to perform the vapor pressure study of the referred compounds allowing the construction of the phase diagrams and determination of the respective triple point coordinates, as well as the standard molar enthalpies of vaporization, sublimation, and fusion for two of the isomers (2,4-DFNB and 3,4-DFNB). For 2,5-difluoronitrobenzene, only liquid vapor pressures were measured enabling the determination of the standard molar enthalpies of vaporization. Combining the thermodynamic parameters of the compounds studied, the following standard (p° = 0.1 MPa) molar enthalpies of formation in the gaseous phase, at T = 298.15 K, were derived: Δ(f)H(m)° (2,4-DFNB, g) = -(296.3 ± 1.8) kJ · mol⁻¹, Δ(f)H(m)° (2,5-DFNB, g) = -(288.2 ± 2.1) kJ · mol⁻¹, and Δ(f)H(m)° (3,4-DFNB, g) = -(302.4 ± 2.1) kJ · mol⁻¹. Using the empirical scheme developed by Cox, several approaches were evaluated in order to identify the best method for estimating the standard molar gas phase enthalpies of formation of these compounds. The estimated values were compared to the ones obtained experimentally, and the approach providing the best comparison with experiment was used to estimate the thermodynamic behavior of the other difluorinated nitrobenzene isomers not included in this study. Additionally, the enthalpies of formation of these compounds along with the enthalpies of formation of the other isomers not studied experimentally, i.e., 2,3-DFNB, 2,6-DFNB, and 3,5-DFNB, were estimated using the composite G3MP2B3 approach together with adequate gas-phase working reactions. Furthermore, we also used this computational approach to calculate the gas-phase basicities, proton and electron affinities, and, finally, adiabatic ionization enthalpies.

The standard ( p ∘ = 0.1 MPa ) molar enthalpies of formation of 2-chloro-4,6-dinitroaniline and 4-chloro-2,6-dinitroaniline, in the gaseous phase, at T = 298.15 K, were derived from the combination of the values of the standard molar enthalpies of formation, in the crystalline phase, and of the standard molar enthalpies of sublimation, at the same temperature. The standard molar enthalpies of formation, in the crystalline phase, were derived from the standard massic energies of combustion, in oxygen, measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of sublimation were calculated, by the application of the Clausius–Clapeyron equation, to the vapour pressures at several temperatures, measured by Knudsen effusion technique. Compound - Δ f H m ∘ (cr) / ( kJ · mol - 1 ) Δ cr g H m ∘ / ( kJ · mol - 1 ) Δ f H m ∘ (g) / ( kJ · mol - 1 ) 2-Chloro-4,6-dinitroaniline 101.0 ± 1.9 115.0 ± 0.9 14.0 ± 2.1 4-Chloro-2,6-dinitroaniline 76.9 ± 1.8 105.2 ± 0.7 28.3 ± 1.9 The values of the standard molar enthalpies of formation of 2-chloro-4,6-dinitroaniline and 4-chloro-2,6-dinitroaniline, in the gaseous phase, at T = 298.15 K, are discussed in terms of enthalpic increments, and the enthalpy of isomerization between the two compounds is compared with the same parameter for two isomers of chloronitroaniline, studied in previous works.

The standard (p∘ = 0.1 MPa) molar enthalpies of formation, in the crystalline state, of 1,5-diaminonaphthalene and 1,8-diaminonaphthalene were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static-bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the dependence of the vapour pressure of the solid isomers of diaminonaphthalene with the temperature, from which the standard molar enthalpies of sublimation were derived using the Clausius–Clapeyron equation. - Δ c U m ∘ ( cr ) / ( kJ · mol - 1 ) Δ f H m ∘ ( cr ) / ( kJ · mol - 1 ) Δ cr g H m ∘ / ( kJ · mol - 1 ) 1,5-Diaminonaphthalene 5402.7 ± 2.2 42.1 ± 2.6 122.5 ± 0.9 1,8-Diaminonaphthalene 5425.9 ± 2.3 65.4 ± 2.6 99.0 ± 0.7 Combining these two experimental values, the gas-phase standard molar enthalpies of formation, at T = 298.15 K, were derived and compared with those estimated using two different empirical methods of Δ f H m ∘ ( g ) estimation: the Cox scheme and the Benson’s Group Method. Moreover, the standard (p∘ = 0.1 MPa) molar entropies and Gibbs energies of sublimation, at T = 298.15 K, were derived for the two diaminonaphthalene isomers.

The standard ( p ∘ = 0.1 MPa ) molar enthalpy of formation, of the 2,5-dibromonitrobenzene, in the crystalline phase, at T = 298.15 K, was derived from the standard massic energy of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the vapour pressures of the crystal as a function of the temperature and applying the Clausius–Clapeyron equation, the standard molar enthalpy of sublimation of the compound, at T = 298.15 K, was calculated. Compound - Δ c U m ∘ ( cr ) /(kJ · mol−1) Δ f H m ∘ ( cr ) /(kJ · mol−1) Δ cr g H m ∘ /(kJ · mol−1) 2,5-Dibromonitrobenzene 2792.2 ± 1.0 43.3 ± 1.3 97.0 ± 0.4 The combination of the values of the standard molar enthalpy of formation, in the crystalline phase, and the standard molar enthalpy of sublimation of the dibromonitrobenzene isomer, allowed the calculation of the standard ( p ∘ = 0.1 MPa ) molar enthalpy of formation, in the gaseous phase, at T = 298.15 K. Additionally, this value was estimated by employing two different methodologies. One based on the conventional Cox Scheme and another one, much more accurate, based on the values of the standard molar enthalpies of formation of 2- and 3-bromonitrobenzene already determined experimentally. Once the best approach was found, it was applied in the estimation of the standard molar enthalpies of formation of the other five isomers.

The standard ( p ∘ = 0.1 MPa ) molar enthalpy of formation of 4,5-dichloro-2-nitroaniline, in the gaseous phase, at T = 298.15 K, was derived from the combination of the values of the standard molar enthalpy of formation, in the crystalline phase, at T = 298.15 K, and the standard molar enthalpy of sublimation, at the same temperature. The standard molar enthalpy of formation, in the crystalline phase, at T = 298.15 K, was derived as −(99.7 ± 1.6) kJ · mol−1 from the standard massic energy of combustion, in oxygen, measured by rotating-bomb combustion calorimetry. The standard molar enthalpy of sublimation was calculated, (109.4 ± 0.9) kJ · mol−1 by the application of the Clausius–Clapeyron equation, to the vapour pressures measured at several temperatures by Knudsen effusion technique. The standard molar enthalpies of formation, in the gaseous phase, of the six dichloro-2-nitroaniline isomers and of the four dichloro-4-nitroaniline isomers were estimated by the Cox Scheme and by the Domalski and Hearing group additivity method and compared with the available experimental values. For the Domalski and Hearing group additivity method four new correction terms were derived.

The present work is part of a research program on the energetics of formation of alkyl substituted benzenediols, aiming the study of the enthalpic effect of the introduction of methyl substituents into benzenediols. In this work we present the results of the thermochemical research on 2-methylresorcinol, 3-methylresorcinol, 4-methylresorcinol, and methylhydroquinone. The standard ( p ∘ = 0.1 MPa ) molar enthalpies of formation, in the crystalline phase, at T = 298.15 K, of the compounds mentioned above were derived from their standard massic energies of combustion, measured by static-bomb combustion calorimetry, while the standard molar enthalpies of sublimation of those compounds were obtained by the temperature dependence of their vapour pressures determined by the Knudsen effusion technique. - Δ c U m ∘ ( cr ) / ( kJ · mol - 1 ) Δ f H m ∘ ( cr ) / ( kJ · mol - 1 ) Δ cr g H m ∘ / ( kJ · mol - 1 ) 2-Methylresorcinol (cr) 3499.3 ± 0.8 −393.6 ± 1.2 99.2 ± 2.3 4-Methylresorcinol (cr) 3491.3 ± 1.1 −401.6 ± 1.4 107.3 ± 3.0 5-Methylresorcinol (cr) 3491.4 ± 1.1 −401.5 ± 1.4 102.9 ± 3.5 Methylhydroquinone (cr) 3492.7 ± 1.4 −400.2 ± 1.7 108.4 ± 3.9 From those experimental values, the standard molar enthalpies of formation of the studied methylbenzenediols in the gaseous phase, at T = 298.15 K were then derived. The results are interpreted in terms of structural contributions to the energetics of the substituted benzenediols and compared with the same parameters estimated from the Cox Scheme. Moreover, the standard ( p ∘ = 0.1 MPa ) molar enthalpies, entropies, and Gibbs energies of sublimation, at T = 298.15 K, were derived for the four isomers of methylbenzenediols.

The standard (p° = 0.1 MPa) molar enthalpies of formation of 2,5- and 2,6-dichloro-4-nitroanilines, in the gaseous phase, at T = 298.15 K, were derived from the combination of the values of the standard molar enthalpies of formation in the crystalline phase, at T = 298.15 K, and the standard molar enthalpies of sublimation, of each compound, at the same temperature. The standard molar enthalpies of formation, in the crystalline phase, at T = 298.15 K, were derived from the standard massic energies of combustion of the two isomers, in oxygen, at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of sublimation were calculated, by application of the Clausius–Clapeyron equation, to the vapour pressures at several temperatures measured by Knudsen effusion technique. Compound Δ f H m ∘ ( cr ) / ( kJ · mol - 1 ) Δ cr g H m ∘ / ( kJ · mol - 1 ) 2,5-Dichloro-4-nitroaniline −85.6 ± 1.9 114.3 ± 0.9 2,6-Dichloro-4-nitroaniline −107.3 ± 1.4 109.2 ± 0.9 The values of the standard (p = 0.1 MPa) molar enthalpies of formation of 2,5- and 2,6-dichloro-4-nitroanilines, in the gaseous phase, at T = 298.15 K, were compared with those estimated by the Cox scheme.

The standard ( p ∘ = 0.1 MPa ) molar enthalpies of formation of the liquid 2-bromophenol and crystalline 4-bromophenol, respectively, Δ f H m ∘ ( l ) = - ( 133.5 ± 1.4 ) kJ · mol - 1 and Δ f H m ∘ (cr) = - ( 152.4 ± 1.4 ) kJ · mol - 1 , were derived from the standard molar energies of combustion, in oxygen, to yield CO2(g) and HBr · 600H2O(l), at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpy of vaporization or sublimation of the compounds, Δ 1 g H m ∘ = ( 55.5 ± 1.3 ) kJ · mol - 1 and Δ cr g H m ∘ = ( 83.1 ± 1.6 ) kJ · mol - 1 . These two thermodynamic parameters yielded the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of 2- and 4-bromophenol, respectively, Δ f H m ∘ ( g ) = - ( 78.0 ± 1.9 ) kJ · mol - 1 and Δ f H m ∘ ( g ) = - ( 69.3 ± 2.1 ) kJ · mol - 1 . The experimental values of the gas-phase enthalpies of formation of each compound were compared with estimates using the empirical scheme developed by Cox and with the calculated values based on high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional at the 6-311++G(d,p) basis set.

The standard ( p ∘ = 0.1 MPa ) molar enthalpies of formation of 2,4,6-trichloronitrobenzene, 2,3,5,6-tetrachloronitrobenzene, and pentachloronitrobenzene, in the crystalline state, at T = 298.15 K, were derived from the standard massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of sublimation, at T = 298.15 K, of 2,4,6-trichloronitrobenzene and pentachloronitrobenzene, were determined from the dependence with the temperature of the vapour pressures, measured by the Knudsen mass-loss effusion method, whereas for 2,3,5,6-tetrachloronitrobenzene, the Calvet drop microcalorimetric technique was used. - Δ c U m ∘ ( cr ) /(kJ · mol−1) - Δ f H m ∘ ( cr ) /(kJ · mol−1) Δ cr g H m ∘ /(kJ · mol−1) 2,4,6-Trichloronitrobenzene 2663.5 ± 1.1 58.6 ± 1.3 86.7 ± 1.1 2,3,5,6-Tetrachloronitrobenzene 2537.1 ± 1.7 67.0 ± 1.9 91.3 ± 2.5 Pentachloronitrobenzene 2387.4 ± 2.4 98.6 ± 2.5 94.5 ± 0.4 The experimental values are also compared with estimates based on G3(MP2)//B3LYP computations, which have also been extended to all the isomers of the trichloro- and tetrachloronitrobenzene that were not studied experimentally.

The standard (p° = 0.1 MPa) molar enthalpies of formation of 2,4-, 2,5-, 3,4- and 3,5-dichloronitrobenzene isomers, in the crystalline state, at T = 298.15 K, were derived from the standard (p° = 0.1 MPa) massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the four isomers, at T = 298.15 K, were obtained by high-temperature Calvet microcalorimetry. - Δ c U m ∘ ( cr ) / ( kJ · mol - 1 ) - Δ f H m ∘ (cr) / ( kJ · mol - 1 ) Δ cr g H m ∘ / ( kJ · mol - 1 ) 2,4-Dichloronitrobenzene 2792.8 ± 0.9 47.4 ± 1.2 87.8 ± 1.7 2,5-Dichloronitrobenzene 2793.0 ± 1.8 47.2 ± 2.0 87.4 ± 2.5 3,4-Dichloronitrobenzene 2774.1 ± 1.2 66.1 ± 1.4 85.8 ± 2.5 3,5-Dichloronitrobenzene 2769.6 ± 0.9 70.6 ± 1.2 83.2 ± 1.5 From the determined experimental results, the values of the gaseous standard (p° = 0.1 MPa) molar enthalpies of formation were derived. The gas-phase enthalpies of formation of all the six chloronitrobenzene isomers were also estimated by the Cox scheme and by computational thermochemistry methods and compared with the available experimental values.

The present work reports the values of the standard (po = 0.1 MPa) molar enthalpies of formation in the condensed phase of the three isomers of monofluorophenol derived from the standard molar energies of combustion, in oxygen, to yield CO2(g) and HF·10H2O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry, as well as the values of the standard molar enthalpies of sublimation or vaporization, at T = 298.15 K, determined using high temperature Calvet microcalorimetry. Combining the former two experimental quantities, the standard molar enthalpies of formation in the gaseous phase were derived, at T = 298.15 K: ΔfHmo(2-fluorophenol, g) = −(294.5 ± 1.6) kJ·mol−1, ΔfHmo(3-fluorophenol, g) = −(292.8 ± 1.7) kJ·mol−1, and ΔfHmo(4-fluorophenol, g) = −(287.6 ± 2.1) kJ·mol−1. The experimental values of the gas-phase enthalpies of formation of each compound were compared with estimates using the empirical scheme developed by Cox and with the calculated values based on high-level density functional...

The standard ( p ° = 0.1 MPa) molar enthalpies of formation in the liquid phase of three isomers of bromoanisole were derived from the standard molar energies of combustion, in oxygen, which yields CO 2 (g) and HBr · 600H 2 O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The determination of the standard molar enthalpies of vaporization of these compounds, at T = 298.15 K, was done by Calvet microcalorimetry using the high-temperature vacuum sublimation technique. Combining the former sets of experimental results, the standard molar enthalpies of formation, in the gas-phase, were derived. The gas-phase enthalpies of formation were also estimated by means of the empirical scheme developed by Cox and by density functional theory calculations performed at the B3LYP/6-31+G(d) level of theory. - Δ c U m ∘ ( l ) / ( kJ · mol - 1 ) - Δ f H m ∘ ( l ) / ( kJ · mol - 1 ) Δ l g H m ∘ / ( kJ · mol - 1 ) 2-Bromoanisole 3629.0 ± 1.4 101.5 ± 1.7 61.8 ± 1.3 3-Bromoanisole 3624.0 ± 1.4 106.5 ± 1.7 58.0 ± 1.2 4-Bromoanisole 3623.8 ± 1.5 106.7 ± 1.8 58.3 ± 1.2 Full-size table Table options View in workspace Download as CSV

The standard (p∘ = 0.1 MPa) molar enthalpies of formation in the liquid phase of three isomers of fluoroanisole were derived from the standard molar energies of combustion, in oxygen, to yield CO2(g) and HF · 10H2O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of vaporization of these compounds, also at T = 298.15 K, were determined using Calvet microcalorimetry. - Δ c U m ∘ ( l ) / ( kJ · mol - 1 ) - Δ f H m ∘ ( l ) / ( kJ · mol - 1 ) Δ l g H m ∘ / ( kJ · mol - 1 ) 2-Fluoroanisole 3629.7 ± 1.0 301.9 ± 1.5 52.2 ± 1.1 3- Fluoroanisole 3617.1 ± 1.1 314.5 ± 1.6 48.1 ± 1.1 4- Fluoroanisole 3622.4 ± 1.2 309.2 ± 1.6 48.7 ± 1.1 The standard molar enthalpies of formation in the gaseous phase, at T = 298.15 K, were derived from the former two experimental quantities. These values are also compared with estimates based on two different methodologies: one using the empirical scheme developed by Cox and the other one based on high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional at the 6-311++G(d,p) basis set. The computed values and the estimated values using the Cox method compare well with the experimental results obtained in this work.

The standard (p∘ = 0.1 MPa) molar enthalpies of formation of 2-, 3-, and 4-chloronitrobenzene isomers, in the crystalline state, at T = 298.15 K, were derived from the standard (p∘ = 0.1 MPa) massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the isomers, at T = 298.15 K, were obtained by high temperature Calvet microcalorimetry. - Δ c U m ∘ ( cr ) /(kJ · mol−1) - Δ c H m ∘ ( cr ) /(kJ · mol−1) - Δ cr g H m ∘ /(kJ · mol−1) 2-Chloronitrobenzene 2939.5 ± 0.7 18.7 ± 1.0 80.9 ± 1.5 3-Chloronitrobenzene 2915.8 ± 0.8 42.4 ± 1.2 82.5 ± 1.5 4-Chloronitrobenzene 2921.7 ± 1.4 36.5 ± 1.6 76.2 ± 2.1 From the determined experimental data, the values of the gaseous standard (p∘ = 0.1 MPa) molar enthalpies of formation for the three monochloronitrobenzene isomers were derived. The gas-phase enthalpies of formation were also estimated by the empirical scheme developed by Cox showing that for meta- and para-chloronitrobenzene the estimated values are in close agreement with the experimental ones whereas, in the case of ortho-chloronitrobenzene it is shown that a different enthalpic interaction increment is needed, when the substituents in the adjacent carbon ring atoms are a chlorine atom and a nitro group.