Pyridine: Experimental and Calculated Chemical Thermodynamic Properties between 0 and 1500°K.; a Revised Vibrational Assignment<sup>1</sup>

McCullough, J. P.; Douslin, D. R.; Messerly, J. F.; Hossenlopp, I. A.; Kincheloe, T. C.; Waddington, Guy

doi:10.1021/ja01573a014

Cited by 94 publications

(55 citation statements)

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“…Table 4 The fitting procedure has been described. (13,19) The C sat,m values determined by adiabatic calorimetry (7) for the temperature range 304Q(T/K)Q347 were included and weighted equally with the vapor pressures. These were included to ensure a smooth junction between the values determined with adiabatic calorimetry and the higher temperature results.…”

Section: Resultsmentioning

confidence: 99%

“…The sample was used previously for heat-capacity studies by adiabatic calorimetry reported by McCullough et al (7) In those studies, the mole fraction purity of the sample was estimated to be 0.9992 by fractional melting. The sample was sealed in glass under vacuum following the heat-capacity measurements by McCullough et al in 1955.…”

Section: Methodsmentioning

confidence: 99%

“…Condensed-phase saturation entropies and enthalpies relative to that of the crystals at T 4 0 were published in 1957 by the Bartlesville thermodynamics research group for the solid phase to T=T tp and for the liquid phases to T=350 K. (7) These values were converted to ITS-90 (10,11) in this research. Details of the conversion are provided separately.…”

Section: P/1tmentioning

confidence: 99%

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Thermodynamic properties of pyridine—I. Vapor pressures, high-temperature heat capacities, densities, critical properties, derived thermodynamic functions, vibrational assignment, and derivation of recommended values

Chirico¹,

Steele²,

Nguyen³

et al. 1996

The Journal of Chemical Thermodynamics

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: P/1tmentioning

confidence: 99%

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Thermodynamic properties of pyridine—I. Vapor pressures, high-temperature heat capacities, densities, critical properties, derived thermodynamic functions, vibrational assignment, and derivation of recommended values

Chirico¹,

Steele²,

Nguyen³

et al. 1996

The Journal of Chemical Thermodynamics

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“…A test of this hypothesis is to compare the thermodynamically predicted pyridine conversion for reactions 1 and 2 with the experimentally determined values, using known free energies (McCullough et al, 1957;Scott, 1971). Calculations were made for a reactant gas taken to be 1% pyridine and 99% hydrogen at 11 bars, the conditions used in the experiments with a pure pyridine feedstock.…”

Section: Page 1106mentioning

confidence: 99%

Interactions between catalytic hydrodesulfurization of thiophene and hydrodenitrogenation of pyridine

1975

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Pyridine hydrodenitrogenation (HDN) is more difficult than thiophene hydrodesulfurization (HDS), and there is a thermodynamic limitation on the first step of the HDN reaction mechanism which occurs, for example, at 5 to 11 bars, at temperatures above about 350°C. Pyridine inhibits the HDS reaction as previously reported, but sulfur compounds have a dual effect on HDN. At low temperatures, thiophene inhibits the reaction by competing with pyridine for hydrogenation sites on the catalyst. This retards the hydrogenation of pyridine to piperidine, reducing the overall reaction rate. At high temperatures the dominant effect is interaction of hydrogen sulfide, an HDS reaction product, with the catalyst to improve its hydrogenolysis (hydrocracking) activity. This increases the rate of piperidine hydrogenolysis, which is rate determining at the latter conditions, and enhances the overall rate of HDN. CHARLES N. SATT'ERFIELD SCOPEThe hydroprocessing of fuels containing relatively large amounts of organonitmgen compounds will become increasingly important in the future in the upgrading of synthetic fuels from oil shale and coal or processing of lower grades of crude petroleum. Organosulfur compounds are present, and the inhibiting effeet of organonitrogen compounds on catalytic hydrodesulfurization is established. However, very little has been published on the effect of organosulfur compounds on hydrodenitrogenation. These two groups of effects were explored by using as model compounds thiophene and PFidine which represent some of the less reactive organosulfur and organonitrogen compounds, respectively.Studies were made with a flow microreactor at temperatures of 200" to 500°C, 4.4 and 11.2 bars pressure, on commercial catalysts consisting of CoMo/Al,03, NiMo/ A1203, NiW/AI2O3 and NiW/SiO2-AlzO3. CONCUSIONS A N D SIGNIFICANCEPyridine, a basic nitrogen compound, severely inhibits the hydrodesulfurization of thiophene on sulfided cobaltmolybdate type of catalysts, in agreement with previous studies. The pattern of this inhibition suggests there are two types of HDS sites involved. The first are postulated to be very active for HDS but very sensitive to nitrogen bases. Sufficient quantities of these bases will completely block these sites and render them inactive for HDS. The second type of sites are much less active for HDS, but they are also less susceptible to pyridine poisoning. These latter sites are responsible for HDS activity after the first type of sites have been blocked.The hydrodenitrogenation of pyridine is more difficult than thioohene HDS, and there appears to be a thermodynamic limitation to the first step in the reaction mechanism. Sulfur compounds have a twofold effect on HDN. At low temperatures they are postulated to compete with pyridine for hydrogenation sites on the catalyst, thereby inhibiting the rate of the hydrogenation step in the pyridine decomposition mechanism. At high temperatures the HDS reaction product hydrogen sulfide interacts with the catalyst to improve the hydrogenolysis activity. Thi...

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“…The spectroscopy and coordination chemistry of Py in the condensed phase has been characterized in detail. [40][41][42][43] The vibrational assignment for Py is available from IR and Raman spectra. [44,45] Spectroscopic characterization of Py adsorbed on metal surfaces through surface-enhanced Raman scattering is a popular approach to probe the strength of chemisorption.…”

Section: Introductionmentioning

confidence: 99%

Infrared Spectrum of the Ag⁺–(Pyridine)₂ Ionic Complex: Probing Interactions in Artificial Metal‐Mediated Base Pairing

Chakraborty¹,

Dopfer²

2011

ChemPhysChem

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The isolated pyridine-Ag(+)-pyridine unit (Py-Ag(+)-Py) is employed as a model system to characterize the recently observed Ag(+)-mediated base pairing in DNA oligonucleotides at the molecular level. The structure and infrared (IR) spectrum of the Ag(+)-Py(2) cationic complex are investigated in the gas phase by IR multiple-photon dissociation (IRMPD) spectroscopy and quantum chemical calculations to determine the preferred metal-ion binding site and other salient properties of the potential-energy surface. The IRMPD spectrum has been obtained in the 840-1720 cm(-1) fingerprint region by coupling the IR free electron laser at the Centre Laser Infrarouge d'Orsay (CLIO) with a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer equipped with an electrospray ionization source. The spectroscopic results are interpreted with quantum chemical calculations conducted at the B3LYP/aug-cc-pVDZ level. The analysis of the IRMPD spectrum is consistent with a σ complex, in which the Ag(+) ion binds to the nitrogen lone pairs of the two Py ligands in a linear configuration. The binding motif of Py-Ag(+)-Py in the gas phase is the same as that observed in Ag(+)-mediated base pairing in solution. Ag(+) bonding to the π-electron system of the aromatic ring is predicted to be a substantially less-favorable binding motif.

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Pyridine: Experimental and Calculated Chemical Thermodynamic Properties between 0 and 1500°K.; a Revised Vibrational Assignment¹

Cited by 94 publications

References 2 publications

Thermodynamic properties of pyridine—I. Vapor pressures, high-temperature heat capacities, densities, critical properties, derived thermodynamic functions, vibrational assignment, and derivation of recommended values

Thermodynamic properties of pyridine—I. Vapor pressures, high-temperature heat capacities, densities, critical properties, derived thermodynamic functions, vibrational assignment, and derivation of recommended values

Interactions between catalytic hydrodesulfurization of thiophene and hydrodenitrogenation of pyridine

Infrared Spectrum of the Ag⁺–(Pyridine)₂ Ionic Complex: Probing Interactions in Artificial Metal‐Mediated Base Pairing

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Pyridine: Experimental and Calculated Chemical Thermodynamic Properties between 0 and 1500°K.; a Revised Vibrational Assignment1

Cited by 94 publications

References 2 publications

Thermodynamic properties of pyridine—I. Vapor pressures, high-temperature heat capacities, densities, critical properties, derived thermodynamic functions, vibrational assignment, and derivation of recommended values

Thermodynamic properties of pyridine—I. Vapor pressures, high-temperature heat capacities, densities, critical properties, derived thermodynamic functions, vibrational assignment, and derivation of recommended values

Interactions between catalytic hydrodesulfurization of thiophene and hydrodenitrogenation of pyridine

Infrared Spectrum of the Ag+–(Pyridine)2 Ionic Complex: Probing Interactions in Artificial Metal‐Mediated Base Pairing

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Product

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Pyridine: Experimental and Calculated Chemical Thermodynamic Properties between 0 and 1500°K.; a Revised Vibrational Assignment¹

Infrared Spectrum of the Ag⁺–(Pyridine)₂ Ionic Complex: Probing Interactions in Artificial Metal‐Mediated Base Pairing