Benzene, 1,4-difluoro-
- Formula: C6H4F2
- Molecular weight: 114.0928
- IUPAC Standard InChI: InChI=1S/C6H4F2/c7-5-1-2-6(8)4-3-5/h1-4H
- 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
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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 |
IR Spectrum
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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: NIST Mass Spectrometry Data Center, William E. Wallace, director
Gas Phase Spectrum
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Additional Data
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| Owner | NIST Standard Reference Data Program Collection (C) 2018 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
|---|---|
| Origin | Sadtler Research Labs Under US-EPA Contract |
| State | gas |
Mass spectrum (electron ionization)
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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: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Due to licensing restrictions, this spectrum cannot be downloaded.
| Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
|---|---|
| Origin | Chuck Anderson, Aldrich Chemical Co. |
| NIST MS number | 107679 |
Gas Chromatography
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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: NIST Mass Spectrometry Data Center, William E. Wallace, director
Van Den Dool and Kratz RI, non-polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Packed | SE-30 | 666. | Peng, Ding, et al., 1988 | He, Supelcoport and Chromosorb, 40. C @ 4. min, 10. K/min, 250. C @ 60. min; Column length: 3.05 m |
Normal alkane RI, non-polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | OV-101 | 665. | Zenkevich, 2005 | 25. m/0.20 mm/0.10 μm, N2/He, 6. K/min; Tstart: 50. C; Tend: 250. C |
References
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), Gas Chromatography, 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]
Peng, Ding, et al., 1988
Peng, C.T.; Ding, S.F.; Hua, R.L.; Yang, Z.C.,
Prediction of Retention Indexes I. Structure-Retention Index Relationship on Apolar Columns,
J. Chromatogr., 1988, 436, 137-172, https://doi.org/10.1016/S0021-9673(00)94575-8
. [all data]
Zenkevich, 2005
Zenkevich, I.G.,
Experimentally measured retention indices., 2005. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), Gas Chromatography, References
- Symbols used in this document:
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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