Modernization and validation of an isoperibol rotating bomb calorimeter for the measurement of energies of combustion of sulphur compounds

A rotating bomb calorimeter belonging to the Laboratory of Chemistry and Process Engineering (UCP) at ENSTA ParisTech since the 1960s was modernized and re-set in order of service for the measurement of heats of combustion of sulphur-containing compounds. The parts of the calorimeter that were replaced concerned essentially the thermal regulation, firing system and data acquisition, while most of the mechanical organs were found to work perfectly. The apparatus was tested extensively and calibrated using standard benzoic acid. The standard energy of combustion of thianthrene was measured to validate the operating protocol for sulphur compounds.     

An easily constructed design of combustion apparatus for the microdetermination of carbon and hydrogen in organic compounds

Summary An easily constructed combustion apparatus for the microdetermination of carbon and hydrogen has been designed for use in a research role as well as for routine analysis.

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Zusammenfassung Ein einfach konstruierter Verbrennungsapparat für die Mikro-C-H-Bestimmung für Forschungszwecke und für den Routinebetrieb wurde beschrieben.

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Résumé On décrit un appareillage pour combustion, facile à réaliser, pour le microdosage du carbone et de l'hydrogène. On peut l'utiliser aussi bien pour la recherche que pour les analyses en série.

     

Thermochemistry of heteroatomic compounds 26.* Calculation of the combustion and formation enthalpy of carbohydrate bicyclophosphites

The enthalpies of combustion for five noncyclic and cyclic phosphites in the condensed state were calculated from the derived equation ΔH_comb/kJ mol^-1 = —860.7 — 107.0(N — n), where N is the number of bonding valent electrons, and c is the number of lone electron pairs of heteroatoms. The dependence presented was used to calculate the combustion enthalpy of five phosphorylated carbohydrates, because these thermochemical values are often difficult to determine by reaction calorimetry. The enthalpies of formation of carbohydrate cyclophosphites were calculated by Hess’s law for the first time.     

Oxide catalyst for the combustion of organic compounds in industrial waste gases

An oxide catalyst for combustion of organic compounds in exhaust gases from plastics plants has been developed. As the active catalyst phase, cupric cobaltate is supported on -Al₂O₃ carrier. Its catalytic activity in the test reaction of propylene oxidation was compared with that of the platinum catalyst used so far. The results show that the new catalyst can replace platinum in the above process.

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. (II) -Al₂O₃. . , .

     

Rapid micro combustion methods for the determination of elements in organic compounds

Summary Advantages of the rapid combustion process for the micro determination of carbon and hydrogen, sulphur, and halogen are discussed, and methods for their estimation are described which have been adopted for routine analysis.

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Zusammenfassung Die Vorteile eines raschen Verbrennungsvorganges für die Mikrobestimmung von Kohlenstoff, Wasserstoff, Schwefel und Halogen werden beschrieben. Methoden für deren quantitative Bestimmung, die sich besonders für Serienanalysen bewährt haben, werden mitgeteilt.

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Résumé On discute les avantages du procédé rapide de combustion pour le microdosage du carbone, de l'hydrogène, du soufre et des halogènes et l'on décrit les méthodes pour leur dosage qui ont été adaptées dans les analyses en série.

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With 5 Figures.     

Enthalpy of sublimation in the study of the solid state of organic compounds. Application to erythritol and threitol

The enthalpies of sublimation of erythritol and L-threitol have been determined at 298.15 K by calorimetry. The values obtained for the two diastereomers differ from one another by 17 kJ mol(-1). An interpretation of these results is based on the decomposition of this thermodynamic property in a term coming from the intermolecular interactions of the molecules in the crystal (delta(int)H degrees) and another one related with the conformational change of the molecules on going from the crystal lattice to the most stable forms in the gas phase (delta(conf)H degrees). This last term was calculated from the values of the enthalpy of the molecules in the gas state and of the enthalpy of the isolated molecules with the crystal conformation. Both quantities were obtained by density functional theory (DFT) calculations at the B3LYP/6-311G++(d,p) level of theory. The results obtained in this study show that the most important contribution to the differences observed in the enthalpy of sublimation are the differences in the enthalpy of conformational change (13 kJ mol(-1)) rather than different intermolecular forces exhibited in the solid phase. This is explained by the lower enthalpy of threitol in the gas phase relative to erythritol, which is attributed to the higher strength of the intramolecular hydrogen bonds in the former. The comparison of the calculated infrared spectra obtained for the two compounds in the gas phase supports this interpretation.     

Coordination compounds of DyIII and NdIII with malonic and succinic acid bispicolylamidrazones

Russian Chemical Bulletin - Dysprosium(iii) and neodymium(iii) complexes with aliphatic dicarboxylic acid bispicolyl-amidrazones were synthesized and studied. X-ray diffraction data showed that the...     

Thermodynamic study on the sublimation of succinic acid and of methyl- and dimethyl-substituted succinic and glutaric acids

The Knudsen mass-loss effusion technique was used to measure the vapour pressures at different temperatures of the following crystalline dicarboxylic acids: succinic acid, between T =  360.11 K and T =  375.14 K; methylsuccinic acid, between T =  343.12 K and T =  360.11 K; 2,2-dimethylsuccinic acid, between T =  350.11 K, and T =  365.11 K; 2-methylglutaric acid, between T =  338.38 K and T =  347.63 K; and 2,2-dimethylglutaric acid between T =  342.18 K and T =  352.66 K. From the temperature dependence of the vapour pressure, the standard molar enthalpies of sublimation were derived by the Clausius–Clapeyron equation and the molar entropies of sublimation at equilibrium pressures were calculated. Using estimated values for the heat capacity differences between the gas and the crystal phases of the studied compounds, the standard, p^o =  10⁵Pa, molar enthalpies, entropies and Gibbs energies of sublimation at T =  298.15 K, were derived:     

Group vector space method for estimating enthalpy of vaporization of organic compounds at the normal boiling point

The specific position of a group in the molecule has been considered, and a group vector space method for estimating enthalpy of vaporization at the normal boiling point of organic compounds has been developed. Expression for enthalpy of vaporization Delta(vap)H(T(b)) has been established and numerical values of relative group parameters obtained. The average percent deviation of estimation of Delta(vap)H(T(b)) is 1.16, which show that the present method demonstrates significant improvement in applicability to predict the enthalpy of vaporization at the normal boiling point, compared the conventional group methods.     

An apparatus for determining the purity of organic compounds

An apparatus is described for determining with an accuracy of 10 per cent the total amount of impurities in small (0.05 cm³) samples of organic compounds, containing more than 98 mole per cent of the main component. A simple method for calculating the degree of purity, applicable to Skau's method, is proposed. A correction for the heat of melting of eutectic mixtures formed by the main component with impurities is introduced.     

Application of an adiabatic precision calorimeter in the field of organic reactions

Adiabatic calorimetry is a suitable method for investigations of reactions because the generated heat remains completely in the reactor. For the investigation of organic reactions, the adiabatic precision calorimeter ACTRON 5 is used. The alcoholyses of phenyl isocyanate and 1,2-butyleneoxide were investigated. The temperature-time course was estimated by means of the nonlinear program TA-kin. Inclusion of the concentration-time course in the estimation procedure led to an increase in the reliability of the parameters. Probes were taken during isoperibolic measurements and were analysed by means of HPLC.     

An improved energy generator for the study of reactions of thermal-energy electrons with organic compounds

Summary The products resulting from the reaction between thermal energy electrons and organic compounds have been investigated to further our knowledge of the mode of action of the electron-capture detector. Thermal energy electrons were generated by maintaining a corona discharge between a stainless steel cathode and a silver/silver chloride anode. The effects of electrode geometry, gas composition, gas flow rate, and the physical properties of the test substances were investigated. The design of the reactor was modified to minimize losses of unchanged substrate. Reaction products of benzaldehyde, tolualdehydes, chlorobenzaldehydes, and dichlorobenzenes were identified by combined gas chromatography — mass spectrometry.     

Application of rotate-bomb calorimeter for determining the standard molar enthalpy of formation of Ln(Pdc)3(Phen)

Thirteen solid ternary complexes Ln(Pdc)₃(Phen) (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu;) have been synthesized in absolute ethanol by rare-earth element chloride low hydrate reacting with the mixed ligands of ammonium pyrrolidinedithiocarbamate (APdc) and 1,10-phenanthroline · H₂O (o-Phen · H₂O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes showed that the Ln³⁺ ion was coordinated with six sulfur atoms of three Pdc⁻ and two nitrogen atoms of o-Phen · H₂O. It was assumed that the coordination number of Ln³⁺ is eight. The constant-volume combustion energies of the complexes, Δ_c U, were determined by a precise rotate-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, Δ_c H _m ^o , and standard molar enthalpies of formation, Δ_f H _m ^o were calculated. The text was submitted by the authors in English.     

Group additivity values for estimating the enthalpy of formation of organic compounds: an update and reappraisal. 1. C, H, and O

This study examines critically the present state and utility of the Benson additivity schemes for estimating the enthalpy of formation of organic compounds. Old and new group additivity values (GAV) for a wide variety of compounds containing C, H and O are described and are revised where appropriate. When new terms are proposed, or old ones significantly altered, the rationale for so doing is provided. Corrections for such items as cis-isomer effects, gauche interactions, ring strain energies, double-bond position, conjugation effects, steric hindrance in aromatic molecules, etc. are included and discussed. Also provided are the thermochemical consequences of functional group replacements, in which one group in a molecule is substituted by another, thus providing quick short cuts to estimating new Δ(f)H(0) values. Results derived from the new additivity terms are consistent with those produced by computational chemistry methods in general use.     

An experimental and theoretical study of the thermal stability of various organic azo compounds

Conclusions A study has been made of the kinetics of the thermal decomposition of various derivatives of nitrobenzene and furazan, attention being given to the relation between thermal stability and molecular energetics.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 313–317, February, 1978.The authors would like to thank L. I. Khmel'nitskii and T. I. Godovikova for having furnished the furazan compounds, and B. Ya. Teitel'baum and V. A. Byl'ev for a useful discussion of the results obtained here.     

Calculations of the enthalpies of combustion of organic compounds by the additive scheme

The enthalpies of combustion of more than 200 organic compounds were analyzed. Group contributions to Δ_c H ^o were calculated and used to estimate the enthalpies of combustion of a wide range of organic substances of various classes.

     

An enthalpy balance approach to the study of metabolic activity in mammalian cells

After a formal explanation of Mayer's enthalpy balance method as applied to biological reaction rates, the history of its application is traced from Rubner's dog to accounting for the energy of muscle contraction. The introduction of microcalorimetry allowed the method generally to be used for cells in vitro and now particular emphasis can be paid to the growth of cells for the production of therapeutically-important heterologous proteins. In these systems, enthalpy balance studies contribute to defining catabolic processes, designing media, understanding the mechanisms of growth and controlling cultures using heat flux as an on-line sensor of metabolic activity.Plenary LectureThe authors are grateful to the BBSRC (UK) for a research grant, 2/3680.     

有机同秩物概念及单取代烷烃同秩物生成焓和电离能变化规律

提出了“有机同秩列”、“有机同秩物”、“有机同秩异构体”等概念体系,并以单取代烷烃同秩物Xi-（CH2）/-H（Xi=F、CI、Br、I、NO2、CN、NC、OH、NH2、SH、COOH、CHO）为例,对其气相标准摩尔生成焓（△rHm）、电离能（IP）的结构-性能关系进行了研究,分别对j=2～8的七组同秩物的生成焓及j=2～4的三组同秩物的电离能建立了数学模型：△rHm（j）=a＋b△iHm（1）＋cPEI（R）和IP（j）：a＋bIP（1）＋bPEI（R）,得到了有意义的结果．研究表明,从有机同秩物的角度可以建立一种新的分子结构．性能相关方法,它与有机同系物方法相互独立又互为补充．本文提出的概念体系不仅增加了新的有机化学理论和概念,还为有机物结构-性能变化规律的研究开辟了新视角．     

Chlorinated organic compounds evolved during the combustion of blends of refuse-derived fuels and coals

The objective of this study was to examine the possible formation of chlorinated organic compounds during the combustion of blends of refuse derived fuels (RDF) and coal under conditions similar to those of an atmospheric fluidized bed combustion (AFBC) system. A series of experiments were conducted using a TG interfaced to FTIR. Additional experiments using a tube furnace preheated to AFBC operating temperatures were also conducted. The combustion products were cryogenically trapped and analyzed with a GC/MS system. The chlorination of phenols and the condensation reactions of chlorophenols were investigated in this study. A possible mechanism for the formation of chlorinated organic compounds such as dibenzodioxins and dibenzofurans, by chlorination and condensation reactions involving phenols, was proposed.The financial support for this work received from the U.S. Department of Energy (Contract No. DE-FG22-94PC94211) and from the Huntsman Thermal Analysis Fellowship is gratefully acknowledged.