Duane R. Kirklin

Enthalpies of combustion of triphenylphosphine and triphenylphosphine oxide

Abstract The energies of combustion of crystalline triphenylphosphine and triphenylphosphine oxide were determined in an aneroid adiabatic rotating bomb calorimeter. The standard molar enthalpies of combustion for the reactions at 298.15 K and p o = 1 × 10 5 Pa are: (C 6 H 5 ) 3 P(cr) + 23O 2 (g) = 18CO 2 (g) + (H 3 PO 4 + 6H 2 O)(aq), Δ c H m o = −(10295.35 ± 2.08) kJ · mol −1 ; (C 6 H 5 ) 3 PO(cr) + 22.5O 2 (g) = 18CO 2 (g) + (H 3 PO 4 + 6H 2 O)(aq), Δ c H m o = −(9971.92 ± 1.90) kJ · mol −1 . The derived enthalpies of formation for triphenylphosphine and triphenylphosphine oxide are: Δ f H m o = (207.02 ± 3.52) kJ · mol −1 and Δ f H m o = −(116.41 ± 3.42) kJ · mol −1 , respectively. The completeness of the combustion reactions was verified by determinations for carbon dioxide through absorption in Ascarite. Ion chromatography was used to analyze the bomb solution quantitatively for the nitrate, orthophosphate, pyrophosphate, and tripolyphosphate ions. The enthalpies and temperatures of melting were determined using d.s.c. The values obtained for the enthalpies of fusion at the melting temperatures for triphenylphosphine and triphenylphosphine oxide were (19.69 ± 0.18) kJ · mol −1 at 354.4 K and (24.22 ± 0.29) kJ · mol −1 at 431.9 K, respectively. Second-order group-contribution values were derived for calculating enthalpies of formation at 298.15 K from the experimental results on triphenylphosphine and triphenylphosphine oxide.

Enthalpy of combustion of 1,4-dimethylcubane dicarboxylate

Abstract The energy of combustion of crystalline 1,4-dimethylcubane dicarboxylate was measured in the NIST aneroid adiabatic rotating calorimeter. The standard molar enthalpy of combustion at 298.15 K and p rmo = 1 × 10 5 Pa for the reaction: C 12 H 12 O 4 (cr) + 13O 2 (g) = 12CO 2 (g) + 6H 2 O(l) is Δ c H m o = −(6518.09±1.42) kJ·mol −1 . The derived enthalpy of formation for crystalline 1,4-dimethylcubane dicarboxylate is −(218.99±2.12) kJ·mol −1 . An estimated enthalpy of formation of an unstrained crystalline 1,4-dimethylcubane dicarboxylate was calculated to be −809.7 kJ·mol −1 using group-contribution values. The corresponding strain energy is 590.7 kJ·mol −1 .

Enthalpy of combustion of adenine

Abstract The enthalpy of combustion for a commercial adenine sample of 99.9 moles per cent purity was measured in an aneroid adiabatic bomb calorimeter. The molar enthalpy of combustion at 298.15 K for the reaction: C 5 H 5 N 5 ( c )+6.25 O 2 ( g ) = 5 CO 2 (g)+2.5 H 2 O (1)+2.5 N 2 ( g ), was Δ c H m o = −(2779.02 ± 1.26) kJ · mol −1 . The corresponding molar enthalpy of formation for adenine, C 5 H 5 N 5 , was calculated to be Δ f H m o = (96.90 ± 1.29) kJ · mol −1 . The present results were found to be in good agreement with those of the earlier work of Stiehler and Huffman.

Properties of Materials and Systems of Importance to Environmental Fates and Remediation. III. Review of Previous Thermodynamic Property Values for Chromium and Some of its Compounds

Twenty-seven (27) crystalline and aqueous chromium species from the NBS Tables of Chemical Thermodynamic Properties were selected based upon their possible importance to environmental fate and remediation processes. Their NBS files were studied to determine the sources of information and the methodology used to determine the NBS selected thermodynamic values. The NBS tables for chromium were compiled in 1966. A literature search was performed to determine the existence of additional data for these species. Documentary data are presented for the thermodynamic properties of these twenty-seven (27) species.

Energy of combustion of triphenylphosphate

Abstract The energy of combustion of crystalline triphenylphosphate was measured in the NBS aneroid adiabatic rotating-bomb calorimeter. The standard molar enthalpy of combustion at 298.15 K and p∘ = 105 Pa for the reaction: C18H15PO4(cr) + 21O2(g) = 18CO2(g) + (H3PO4 + 6H2O)(aq) is ΔcHm∘ = −(9259.31 ± 4.96) kJ · mol−1. The derived standard molar enthalpy of formation for crystalline triphenylphosphate is ΔfHm∘ = −(829.26 ± 5.72) kJ · mol−1. Enthalpies of formation of the liquid and gas phases were calculated using literature values of the enthalpies of fusion and vaporization. Group-contribution values were derived for estimating enthalpies of formation of aromatic phosphates in the gas, liquid, and solid phases.

Enthalpy of Formation of Triphenylphosphine Sulfide

The first measurements of the enthalpies of combustion, sublimation, and fusion of an organo-phosphorus sulfide, triphenylphosphine sulfide, are reported: δcHmo(C18H15PS, cr)=−(10752.58 ±2.90), δsubHmo(C18H15PS, 403 K)=(136.80±6.09), and δfusHmo(C18H15PS, Tm=435.92 K) =(30.53±0.21) kJ·mol−1. Correction of the phase change enthalpies toT=298.15K and po =0.1 MPa results in the standard phase change enthalpy values of δsubHmo(298.15 K)=(142.8 ±6.8) and δfusHmo(298.15 K)=(19.28±0.21) kj·mol−1. Accordingly, the enthalpies of formation of solid, liquid, and gaseous triphenylphosphine sulfide are derived: δfHmo(C18H15PS, cr) =(63.20±2.56), δfHmo(C18H15PS, l)=(82.48±2.57), and δfHmo(C18H15PS, g)=(206.0±7.3) kJ·mol−1. From these ancillary data, the P=S double-bond enthalpy is 394 kJ-mol−1 and in good agreement with earlier reaction calorimetry results. These phosphorus sulfide values are compared with those for the arsenic sulfides. Plausibility arguments are given for our results.

The variability of municipal solid waste and its relationship to the determination of the calorific value of refuse-derived fuels

Abstract A study was carried out to examine the variability, over a two-week period, of municipal solid waste (MSW) at the Baltimore County Resource Recovery Facility in Cockeysville, Haryland. Samples of municipal solid waste which had been processed through a primary shredder were collected daily for two weeks. After the total moisture content was determined, the samples were reduced in particle size to 2mm or less. A total of 40 samples were prepared for measurements. Testing was carried out for residual moisture, furnace ash, bomb ash, and calorific or higher heating value. The daily variability (i.e., excluding the within bag variability) of MSW is 36 % and 37 % for moisture and ash, respectively. The combustible fraction of MSW is directly related to the moisture and bomb-ash free higher heating value (HHV3-B) which has a daily variability (i.e., excluding the within bag variability) of only 4%. Statistical analysis of the data suggests that the day to day variability of MSW constitutes 70 to 30% of the overall variability, with the other variables being errors in sampling, size reduction procedures, and measurement techniques.

Enthalpy of combustion of purine

Abstract The enthalpy of combustion of a commercial purine sample of 99.8 moles per cent purity was measured in an aneroid adiabatic bomb calorimeter. The molar enthalpy of combustion at 298.15 K for the reaction: C 5 H 4 N 4 (cr)+6O 2 (g)=5CO 2 (g)+2H 2 O(1)+2N 2 (g) is Δ c H m o = −(2708.62±2.31) kJ·mol −1 ( p o = 101.325 kPa). The corresponding molar enthalpy of formation of purine, C 5 H 4 N 4 , is Δ f H m o = (169.41±2.65) kJ·mol −1 . The estimation of Δ f H m o for purine by three calculated paths yielded 180.15 kJ·mol −1 . Some reasons for the difference are proposed.

Vibrational spectra and barrier to internal rotation of BCl2SH and BCl2SD

Abstract Recent interest in SH(D) derivatives of BCl3 prompted a vibrational study of BCl2SH and BCl2SD. Raman spectra of the liquid and gas phases were recorded from 100 to 2700 cm−1. Infrared spectra of the vapors were recorded from 200 to 2700 cm−1. All nine fundamentals were observed and assigned for both molecules. The observation of seven polarized and two depolarized Raman bands confirms the planar configuration. The infrared vapor spectra shows the fundamental and three hot bands of the SH(D) torsional vibration. A comparison of our spectral results with an earlier study is presented. The structure of the infrared torsional band allowed calculation of the barrier to internal rotation. Barrier values of 11.8 and 12.4 kcal/mole were calculated for the protonated and deuterated molecules, respectively, utilizing the V = ( V 2 2 ) (1 − cos 2φ) potential. Potential barrier values of 10.2 and 9.9 kcal/mole were obtained with the quartic potential, V = A (z4 + Bz2). The two different potential barrier calculations afforded an evaluation of the choice of potentials for double minimum systems with high barriers. A barrier of about 11 ± 3 kcal/mole is estimated for this species. Thermodynamic functions were also calculated.

Characterization of refuse-derived fuel at various stages of processing

Abstract The calorific value, moisture, ash, sulfur and chlorine contents were measured by the National Bureau of Standards (NBS) and the results analyzed to characterize refuse-derived fuel (RDF) as a function of the type of processing that the RDF had undergone. The RDF was separated from a municipal solid waste (MSW) sample from New Castle County, Delaware at the Bureau of Mines (BuM) pilot resource recovery plant in College Park, Maryland. The RDF streams were collected at seven points after various stages of processing through air classifiers and trommels. NBS characterized RDF as a function of the type of processing that the RDF had undergone. Air classifiers were very effective in separating the light components of RDF (i.e. paper and plastic films) from the heavier components of RDF. A trommel in the RDF separation scheme removes some of the undesirable characteristics of RDF, namely, the non-combustible, sulfur- and chlorine-containing components of RDF.