Benzene, 1,4-difluoro-
- Formula: C6H4F2
- Molecular weight: 114.0928
- IUPAC Standard InChIKey: QUGUFLJIAFISSW-UHFFFAOYSA-N
- CAS Registry Number: 540-36-3
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: Benzene, p-difluoro-; p-Difluorobenzene; 1,4-Difluorobenzene; para-Difluorobenzene
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Gas phase thermochemistry data
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | -73.30 ± 0.25 | kcal/mol | Ccr | Good, Lacina, et al., 1962 | Corrected for CODATA value of ΔfH |
Reaction thermochemistry data
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
RCD - Robert C. Dunbar
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.
Individual Reactions
C6H3F2- + =
By formula: C6H3F2- + H+ = C6H4F2
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 380.2 ± 2.1 | kcal/mol | G+TS | Buker, Nibbering, et al., 1997 | gas phase; B |
ΔrH° | 379.8 ± 3.1 | kcal/mol | G+TS | Briscese and Riveros, 1975 | gas phase; < MeOH, <= EtOH; value altered from reference due to change in acidity scale; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 372.1 ± 2.0 | kcal/mol | IMRE | Buker, Nibbering, et al., 1997 | gas phase; B |
ΔrG° | 371.7 ± 3.0 | kcal/mol | IMRB | Briscese and Riveros, 1975 | gas phase; < MeOH, <= EtOH; value altered from reference due to change in acidity scale; B |
By formula: H4N+ + C6H4F2 = (H4N+ • C6H4F2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 13. | kcal/mol | PHPMS | Deakyne and Meot-Ner (Mautner), 1985 | gas phase; Entropy change calculated or estimated; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 20. | cal/mol*K | N/A | Deakyne and Meot-Ner (Mautner), 1985 | gas phase; Entropy change calculated or estimated; M |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
5.1 | 395. | PHPMS | Deakyne and Meot-Ner (Mautner), 1985 | gas phase; Entropy change calculated or estimated; M |
By formula: Cl- + C6H4F2 = (Cl- • C6H4F2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 13.8 ± 2.0 | kcal/mol | IMRE | Larson and McMahon, 1984 | gas phase; B,M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 21.6 | cal/mol*K | N/A | Larson and McMahon, 1984 | gas phase; switching reaction(Cl-)ClCOOCH3, Entropy change calculated or estimated; Larson and McMahon, 1984, 2; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 7.3 ± 2.0 | kcal/mol | IMRE | Larson and McMahon, 1984 | gas phase; B,M |
By formula: C6H6+ + C6H4F2 = (C6H6+ • C6H4F2)
Bond type: Charge transfer bond (positive ion)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 11.3 | kcal/mol | MPI | Ernstberger, Krause, et al., 1990 | gas phase; M |
By formula: C6H4F2+ + C6H4F2 = (C6H4F2+ • C6H4F2)
Bond type: Charge transfer bond (positive ion)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 8.8 | kcal/mol | MPI | Ernstberger, Krause, et al., 1990 | gas phase; M |
By formula: Cr+ + C6H4F2 = (Cr+ • C6H4F2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 29.0 | kcal/mol | RAK | Ryzhov, 1999 | RCD |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias
Data compiled as indicated in comments:
B - John E. Bartmess
LL - Sharon G. Lias and Joel F. Liebman
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 9.1589 ± 0.0005 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
Proton affinity (review) | 171.8 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 165.6 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
9.1590 ± 0.0004 | TE | Rieger, Reiser, et al., 1992 | LL |
9.1588 ± 0.0002 | TE | Reiger, 1990 | LL |
9.14 | PE | Bieri, Asbrink, et al., 1981 | LLK |
9.137 ± 0.004 | EQ | Lias and Ausloos, 1978 | LLK |
9.18 | S | Gilbert and Sandorfy, 1974 | LLK |
9.15 ± 0.06 | PE | Clark and Frost, 1967 | RDSH |
9.15 | PI | Bralsford, Harris, et al., 1960 | RDSH |
9.4 | PE | Bieri, Asbrink, et al., 1981 | Vertical value; LLK |
9.29 | PE | Sell, Mintz, et al., 1978 | Vertical value; LLK |
9.15 | PE | Streets and Ceasar, 1973 | Vertical value; LLK |
9.4 ± 0.03 | PE | Klessinger, 1972 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
C4H2F2+ | 15.27 | C2H2 | EI | Momigny and Wirtz-Cordier, 1962 | RDSH |
C6H4F+ | 15.5 ± 0.1 | F | EI | Majer and Patrick, 1962 | RDSH |
De-protonation reactions
C6H3F2- + =
By formula: C6H3F2- + H+ = C6H4F2
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 380.2 ± 2.1 | kcal/mol | G+TS | Buker, Nibbering, et al., 1997 | gas phase; B |
ΔrH° | 379.8 ± 3.1 | kcal/mol | G+TS | Briscese and Riveros, 1975 | gas phase; < MeOH, <= EtOH; value altered from reference due to change in acidity scale; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 372.1 ± 2.0 | kcal/mol | IMRE | Buker, Nibbering, et al., 1997 | gas phase; B |
ΔrG° | 371.7 ± 3.0 | kcal/mol | IMRB | Briscese and Riveros, 1975 | gas phase; < MeOH, <= EtOH; value altered from reference due to change in acidity scale; B |
References
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Good, Lacina, et al., 1962
Good, W.D.; Lacina, J.L.; Scott, D.W.; McCullough, J.P.,
Combustion calorimetry of organic fluorine compounds. The heats of combustion and formation of the difluorobenzenes, 4-fluorotoluene and m-trifluorotoluic acid,
J. Phys. Chem., 1962, 66, 1529-1532. [all data]
Buker, Nibbering, et al., 1997
Buker, H.H.; Nibbering, N.M.M.; Espinosa, D.; Mongin, F.; Schlosser, M.,
Additivity of substituent effects in the fluoroarene series: Equilibrium acidity in the gas phase and deprotonation rates in ethereal solution,
Tetrahed. Lett., 1997, 38, 49, 8519-8522, https://doi.org/10.1016/S0040-4039(97)10303-3
. [all data]
Briscese and Riveros, 1975
Briscese, S.M.J.; Riveros, J.M.,
Gas phase nucleophilic reactions of aromatic systems,
J. Am. Chem. Soc., 1975, 97, 230. [all data]
Deakyne and Meot-Ner (Mautner), 1985
Deakyne, C.A.; Meot-Ner (Mautner), M.,
Unconventional Ionic Hydrogen Bonds. 2. NH+ pi. Complexes of Onium Ions with Olefins and Benzene Derivatives,
J. Am. Chem. Soc., 1985, 107, 2, 474, https://doi.org/10.1021/ja00288a034
. [all data]
Larson and McMahon, 1984
Larson, J.W.; McMahon, T.B.,
Hydrogen bonding in gas phase anions. An experimental investigation of the interaction between chloride ion and bronsted acids from ICR chloride exchange equilibria,
J. Am. Chem. Soc., 1984, 106, 517. [all data]
Larson and McMahon, 1984, 2
Larson, J.W.; McMahon, T.B.,
Gas phase negative ion chemistry of alkylchloroformates,
Can. J. Chem., 1984, 62, 675. [all data]
Ernstberger, Krause, et al., 1990
Ernstberger, B.; Krause, H.; Kiermeier, A.; Neusser, H.J.,
Multiphoton ionization and dissociation of mixed van der Waals clusters in a linear reflectron time-of-flight mass spectrometer,
J. Chem. Phys., 1990, 92, 9, 5285, https://doi.org/10.1063/1.458603
. [all data]
Ryzhov, 1999
Ryzhov, V.,
Binding Energies of Chromium Cations with Fluorobenzenes from Radiative Association Kinetics,
Int. J. Mass Spectrom., 1999, 185/186/187, 913. [all data]
Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G.,
Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update,
J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018
. [all data]
Rieger, Reiser, et al., 1992
Rieger, D.; Reiser, G.; Muller-Dethlefs, K.; Schlag, E.W.,
Zero kinetic energy photoelectron spectroscopy of p-difluorobenzene,
J. Phys. Chem., 1992, 96, 12. [all data]
Reiger, 1990
Reiger, D.,
[Title unavailable],
Diplomarbeit, Techn. Universitat Munich, 1990. [all data]
Bieri, Asbrink, et al., 1981
Bieri, G.; Asbrink, L.; Von Niessen, W.,
30.4 nm He(II) photoelectron spectra of organic molecules. Part IV. Fluoro-compounds (C,H,F),
J. Electron Spectrosc. Relat. Phenom., 1981, 23, 281. [all data]
Lias and Ausloos, 1978
Lias, S.G.; Ausloos, P.J.,
eIonization energies of organic compounds by equilibrium measurements,
J. Am. Chem. Soc., 1978, 100, 6027. [all data]
Gilbert and Sandorfy, 1974
Gilbert, R.; Sandorfy, C.,
Rydberg transitions in the ultraviolet spectra of difluorobenzenes,
Chem. Phys. Lett., 1974, 27, 457. [all data]
Clark and Frost, 1967
Clark, I.D.; Frost, D.C.,
A study of the energy levels in benzene and some fluorobenzenes by photoelectron spectroscopy,
J. Am. Chem. Soc., 1967, 89, 244. [all data]
Bralsford, Harris, et al., 1960
Bralsford, R.; Harris, P.V.; Price, W.C.,
The effect of fluorine on the electronic spectra and ionization potentials of molecules,
Proc. Roy. Soc. (London), 1960, A258, 459. [all data]
Sell, Mintz, et al., 1978
Sell, J.A.; Mintz, D.M.; Kupperman, A.,
Photoelectron angular distributions of carbon-carbon π electrons in ethylene, benzene, and their fluorinated derivatives,
Chem. Phys. Lett., 1978, 58, 601. [all data]
Streets and Ceasar, 1973
Streets, D.G.; Ceasar, G.P.,
Inductive mesomeric effects on the π orbitals of halobenzenes,
Mol. Phys., 1973, 26, 1037. [all data]
Klessinger, 1972
Klessinger, M.,
Ionization potentials of substituted benzenes,
Angew. Chem. Int. Ed. Engl., 1972, 11, 525. [all data]
Momigny and Wirtz-Cordier, 1962
Momigny, J.; Wirtz-Cordier, A.M.,
Les effets de l'impact electronique sur des derives dihalogenes du benzene,
Ann. Soc. Sci. Bruxelles, 1962, 76, 164. [all data]
Majer and Patrick, 1962
Majer, J.R.; Patrick, C.R.,
Electron impact on some halogenated aromatic compounds,
J. Chem. Soc. Faraday Trans., 1962, 58, 17. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy IE (evaluated) Recommended ionization energy T Temperature ΔfH°gas Enthalpy of formation of gas at standard conditions ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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