Note on heats of formation of ethyl and propyl peroxides

Stathis, E.C.; Egerton, Alfred Charles

doi:10.1039/tf9403500606

Cited by 14 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermodynamic properties of peroxides are listed in Table 3 together with literature data. Several levels of theory and experiment [41][42][43] have been employed to study the heats of formation of peroxides. A nearly complete compilation of the available thermochemical parameters of peroxides can be obtained from the works of Bozzelli and coworkers.…”

Section: Resultsmentioning

confidence: 99%

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

Sumathi

Green

2003

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Ab initio molecular orbital theory calculations are performed at the complete basis set (CBS-Q) level to determine thermochemical parameters (D f H 298 , S 298 , C T p ) of alcohols, methyl ethers, formates, acetates, hydroperoxides, methyl alkylperoxides and the corresponding methoxy, primary and secondary alkoxy radicals derived from these molecular families. A consistent set of 12 Benson groups transferable among these six molecular families is derived from CBS-Q results via regression together with 20 hydrogen bond increment (HBI) group values for estimating the thermochemistry of oxymethyl ( CH 2 OX), oxyethyl (CH 3 CH OX), oxyisopropyl ((CH 3 ) 2 C OX) with varying substituent X ( ¼ H, CH 3 , C(O)H, C(O)CH 3 , OH, OCH 3 ) and alkoxycarbonyl (ROC(O) ) radicals. These new groups are useful in estimating the thermochemistry of large oxygenated molecules and radicals involved in complex chemical reaction mechanisms. The kinetics of nearly 50 elementary bimolecular hydrogen abstraction reactions belonging to eight different reaction families viz.,are studied using transition state theory coupled with CBS-Q energetics. The calculated barrier height within a given reaction family varies with the nature of the b substituents. The reliability of the calculated variations in the barrier height with varying b substituents is determined through comparison of the calculated rate constants with the scarcely available experimental data. Thermodynamically consistent generic rate rules have been derived in terms of group additivity. New transferable supergroup values corresponding to the thermochemistry of the reactive moiety in transition structures are developed. The effect of non-next neighbor substituents on the enthalpy of the supergroup is quantified using Evans-Polanyi relations.

show abstract

Section: Resultsmentioning

confidence: 99%

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

Sumathi

Green

2003

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Experimental values of Δ H f ° 298 are available for HOOH (−32.5 kcal/mol), C 2 H 5 OOH (−47.6 kcal/mol), i -C 3 H 7 OOH (−65.0 kca/mol), t -C 4 H 9 OOH (−58.8 kcal/mol), and several cycloalkyl hydroperoxides. Another experimental Δ H f ° 298 value for ethyl hydroperoxide was reported with a high uncertainty, −45 ± 12 kcal/mol. , Benson 17 and Baldwin comment that the enthalpy data, −47.6 kcal/mol for C 2 H 5 OOH and −65.0 kca/mol for i -C 3 H 7 OOH quoted by Cox and Pilcher, are inconsistent with data on other hydroperoxides. Benson 17 estimated Δ H f ° 298 (C 2 H 5 OOH) = −40.2 kcal/mol and Δ H f ° 298 ( i -C 3 H 7 OOH) = −49.3 kcal/mol based on the group additivity approach using 48.0 kcal/mol 17 as O−O bond energies.…”

Section: Introductionmentioning

confidence: 93%

Ab Initio Study of α-Chlorinated Ethyl Hydroperoxides CH₃CH₂OOH, CH₃CHClOOH, and CH₃CCl₂OOH: Conformational Analysis, Internal Rotation Barriers, Vibrational Frequencies, and Thermodynamic Properties

et al. 1996

View full text Add to dashboard Cite

Ab initio calculations were performed on CH3CH2OOH, CH3CHClOOH, and CH3CCl2OOH molecules using the Gaussian92 system of programs. Geometries of stable rotational conformers and transition states for internal rotation were optimized at the RHF/6-31G* and MP2/6-31G* levels of theory. Harmonic vibrational frequencies were computed at the RHF/6-31G* level of theory. Potential barriers for internal rotations were calculated at the MP2/6-31G**/HF/6-31G* level. Parameters of the Fourier expansion of the hindrance potentials have been tabulated. Standard entropies (S°298) and heat capacities (C p (T)'s, 300 ≤ T/K ≤ 1500) were calculated using the rigid-rotor−harmonic-oscillator approximation based on the information obtained from the ab initio studies. Contributions from hindered rotors were calculated by summation over the energy levels obtained by direct diagonalization of the Hamiltonian matrix of hindered internal rotations. Enthalpies of formation for these three molecules were calculated using isodesmic reactions. Enthalpies of formation were calculated to be ΔH f°298(CH3CH2OOH) = −41.5 ± 1.5 kcal mol-1, ΔH f°298(CH3CHClOOH) = −50.9 ± 3.4 kcal mol-1, and ΔH f°298(CH3CCl2OOH) = −55.3 ± 2.2 kcal mol-1. Entropies (S°298) are calculated to be 76.1, 79.2 and 86.6 cal mol-1 K-1 for CH3CH2OOH, CH3CHClOOH, and CH3CCl2OOH, respectively.

show abstract

“…A number of researchers have worked at calculating and improving accuracy values on alkyl peroxides and their peroxy radicals over the past several decades. Pedley suggested −47.54 ± 14.03 kcal mol –1 as the enthalpy of formation for CH 3 CH 2 OOH, which was derived from two reported experimental values: −57.85 ± 14.00 kcal mol –1 in the liquid phase from a study by Stathis, and −47.55 ± 14.04 kcal mol –1 in the gas phase from Egerton . The enthalpy of formation of n-propyl hydroperoxide (CH 3 CH 2 CH 2 OOH) was reported as −76.01 ± 15.00 kcal mol –1 (liquid phase) by Stathis .…”

Section: Introductionmentioning

confidence: 99%

“…Pedley suggested −47.54 ± 14.03 kcal mol –1 as the enthalpy of formation for CH 3 CH 2 OOH, which was derived from two reported experimental values: −57.85 ± 14.00 kcal mol –1 in the liquid phase from a study by Stathis, and −47.55 ± 14.04 kcal mol –1 in the gas phase from Egerton . The enthalpy of formation of n-propyl hydroperoxide (CH 3 CH 2 CH 2 OOH) was reported as −76.01 ± 15.00 kcal mol –1 (liquid phase) by Stathis . Burke et al have recently published a review on standard enthalpies of formation and standard entropy data on C1–C4 species and included C2–C4 alkyl peroxide species; however, thermochemistry on methyl peroxide was not discussed.…”

Section: Introductionmentioning

confidence: 99%

“…16 The enthalpy of formation of n-propyl hydroperoxide (CH 3 CH 2 CH 2 OOH) was reported as −76.01 ± 15.00 kcal mol −1 (liquid phase) by Stathis. 15 Burke et al 17 have recently published a review on standard enthalpies of formation and standard entropy data on C1−C4 species and included C2−C4 alkyl peroxide species; however, thermochemistry on methyl peroxide was not discussed. Current literature values and values calculated in this study for ethyl and propyl hydroperoxides are near −39.0 and −44.0 kcal mol −1 , respectively, very different from the data recommended by Pedley.…”

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermochemical Properties (Δ_fH°(298 K), S°(298 K), C_p(T)) and Bond Dissociation Energies for C1–C4 Normal Hydroperoxides and Peroxy Radicals

Wang

Bozzelli

2016

J. Chem. Eng. Data

View full text Add to dashboard Cite

Structure and thermochemical properties of the normal hydroperoxides, C n H2n+1OOH (1 ≤ n ≤ 4), and corresponding peroxy radicals, C n H2n+1OO·(1 ≤ n ≤ 4), are determined by density functional M06-2X, multilevel G4, composite CBS-QB3, and CBS-APNO level calculations. Unique to this study is that the Δf H°298 values are determined using several isodesmic reactions which utilize experimental standard enthalpy data for CH3OOCH3 and CH3CH2OOCH2CH3 as reference species, where previous studies used atomization or work reactions with alcohols or other nonperoxide species. The S°298 and Cp (T) (300 ≤ T/K ≤ 1500) from vibration, translation, and external rotation contributions are calculated based on the vibration frequencies and structures obtained from the density functional study. Potential barriers for the internal rotations are calculated at B3LYP/6-31+G(d,p) level, the hindered internal rotation contributions to S°298 and Cp (T) are calculated using direct integration over energy levels of the internal rotational potentials. The results show the following Δf H°298 values (units in kcal mol–1): CH3OOH (−31.0), CH3CH2OOH (−39.0), CH3CH2CH2OOH (−44.0), CH3CH2CH2CH2OOH (−48.9),CH3OO· (2.4), CH3CH2OO· (−6.2), CH3CH2CH2OO· (−11.4), and CH3CH2CH2CH2OO· (−16.6). Bond dissociation energies for the R–OOH, RO–OH, ROO–H, R–OOj, and RO–Oj bonds are reported. The enthalpy values from the use of experimental data as a reference show very good agreement and support the data obtained from calculation methods. They should be used for reference values. Entropy and heat capacity values show good agreement with the calculation literature. The standard entropies for butyl hydroperoxide, propyl peroxy, and butyl peroxy are corrected.

show abstract

Note on heats of formation of ethyl and propyl peroxides

Cited by 14 publications

References 0 publications

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

Ab Initio Study of α-Chlorinated Ethyl Hydroperoxides CH₃CH₂OOH, CH₃CHClOOH, and CH₃CCl₂OOH: Conformational Analysis, Internal Rotation Barriers, Vibrational Frequencies, and Thermodynamic Properties

Thermochemical Properties (Δ_fH°(298 K), S°(298 K), C_p(T)) and Bond Dissociation Energies for C1–C4 Normal Hydroperoxides and Peroxy Radicals

Contact Info

Product

Resources

About

Note on heats of formation of ethyl and propyl peroxides

Cited by 14 publications

References 0 publications

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

Oxygenate, oxyalkyl and alkoxycarbonyl thermochemistry and rates for hydrogen abstraction from oxygenates

Ab Initio Study of α-Chlorinated Ethyl Hydroperoxides CH3CH2OOH, CH3CHClOOH, and CH3CCl2OOH: Conformational Analysis, Internal Rotation Barriers, Vibrational Frequencies, and Thermodynamic Properties

Thermochemical Properties (ΔfH°(298 K), S°(298 K), Cp(T)) and Bond Dissociation Energies for C1–C4 Normal Hydroperoxides and Peroxy Radicals

Contact Info

Product

Resources

About

Ab Initio Study of α-Chlorinated Ethyl Hydroperoxides CH₃CH₂OOH, CH₃CHClOOH, and CH₃CCl₂OOH: Conformational Analysis, Internal Rotation Barriers, Vibrational Frequencies, and Thermodynamic Properties

Thermochemical Properties (Δ_fH°(298 K), S°(298 K), C_p(T)) and Bond Dissociation Energies for C1–C4 Normal Hydroperoxides and Peroxy Radicals