Benzene, 1,3-dimethyl-
- Formula: C8H10
- Molecular weight: 106.1650
- IUPAC Standard InChIKey: IVSZLXZYQVIEFR-UHFFFAOYSA-N
- CAS Registry Number: 108-38-3
- 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: m-Xylene; m-Dimethylbenzene; m-Xylol; 1,3-Dimethylbenzene; 1,3-Xylene; 2,4-Xylene; m-Methyltoluene; meta-Xylene; NSC 61769; UN 1307; 1,3-dimethylbenzene (m-xylene)
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Condensed phase thermochemistry data
Go To: Top, Gas phase ion energetics data, Ion clustering data, References, Notes
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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°liquid | -6.08 ± 0.18 | kcal/mol | Ccb | Prosen, Johnson, et al., 1946 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°liquid | -1087.37 ± 0.13 | kcal/mol | Cm | Coops, Mulder, et al., 1946 | Reanalyzed by Cox and Pilcher, 1970, Original value = -1086.94 ± 0.13 kcal/mol; Corresponding ΔfHºliquid = -6.61 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
ΔcH°liquid | -1087.92 ± 0.15 | kcal/mol | Ccb | Prosen, Johnson, et al., 1946 | Corresponding ΔfHºliquid = -6.06 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
ΔcH°liquid | -1091.7 | kcal/mol | Ccb | Richards and Barry, 1915 | At 291 K; Corresponding ΔfHºliquid = -2.3 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
ΔcH°liquid | -1095.0 | kcal/mol | Ccb | Richards and Jesse, 1910 | At 293 K; Corresponding ΔfHºliquid = 1.0 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°liquid | 60.660 | cal/mol*K | N/A | Pitzer and Scott, 1943 | DH |
S°liquid | 60.30 | cal/mol*K | N/A | Huffman, Parks, et al., 1930 | Extrapolation below 90 K, 66.94 J/mol*K.; DH |
Constant pressure heat capacity of liquid
Cp,liquid (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
44.128 | 298.15 | Grolier, Roux-Desgranges, et al., 1993 | DH |
43.3915 | 298.15 | Fortier and Benson, 1979 | DH |
43.3752 | 298.15 | Fortier and Benson, 1977 | DH |
47.61 | 336. | Swietoslawski and Zielenkiewicz, 1958 | Mean value 21 to 106 C.; DH |
44.10 | 298. | Kurbatov, 1947 | T = 16 to 132 C, mean Cp, three temperatures.; DH |
43.781 | 298.15 | Pitzer and Scott, 1943 | T = 14 to 320 K.; DH |
41.90 | 275.3 | Huffman, Parks, et al., 1930 | T = 96 to 275 K. Value is unsmoothed experimental datum.; DH |
42.59 | 303. | Willams and Daniels, 1924 | T = 303 to 348 K. Equation only.; DH |
Gas phase ion energetics data
Go To: Top, Condensed phase thermochemistry data, Ion clustering 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
MM - Michael M. Meot-Ner (Mautner)
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
View reactions leading to C8H10+ (ion structure unspecified)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 8.55 ± 0.02 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
Proton affinity (review) | 194.1 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 187.9 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Proton affinity at 298K
Proton affinity (kcal/mol) | Reference | Comment |
---|---|---|
195.2 | Aue, Guidoni, et al., 2000 | Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM |
193.4 ± 0.29 | Fernandez, Jennings, et al., 1989 | T = 370 - 750K; Reference Sprot(CH3)2O = 16.5 J/mol K in Hunter and Lias, 1998 needs to be re-evaluated; MM |
Gas basicity at 298K
Gas basicity (review) (kcal/mol) | Reference | Comment |
---|---|---|
188.3 | Aue, Guidoni, et al., 2000 | Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM |
187.0 ± 0.43 | Fernandez, Jennings, et al., 1989 | T = 370 - 750K; Reference Sprot(CH3)2O = 16.5 J/mol K in Hunter and Lias, 1998 needs to be re-evaluated; MM |
Protonation entropy at 298K
Protonation entropy (cal/mol*K) | Reference | Comment |
---|---|---|
4.59 | Fernandez, Jennings, et al., 1989 | T = 370 - 750K; Reference Sprot(CH3)2O = 16.5 J/mol K in Hunter and Lias, 1998 needs to be re-evaluated; MM |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
8.56 | PE | Howell, Goncalves, et al., 1984 | LBLHLM |
8.57 ± 0.01 | EQ | Lias and Ausloos, 1978 | LLK |
8.90 ± 0.05 | EI | Loudon and Mazengo, 1974 | LLK |
8.50 ± 0.02 | PE | Maier and Turner, 1973 | LLK |
8.55 ± 0.05 | PI | Akopyan and Vilesov, 1966 | RDSH |
8.56 | PI | Bralsford, Harris, et al., 1960 | RDSH |
8.56 ± 0.01 | PI | Watanabe, 1957 | RDSH |
8.56 | PE | Howell, Goncalves, et al., 1984 | Vertical value; LBLHLM |
8.82 | PE | Kimura, Katsumata, et al., 1981 | Vertical value; LLK |
8.55 | PE | Koenig, Tuttle, et al., 1974 | Vertical value; LLK |
8.71 ± 0.015 | PE | Kobayashi and Nagakura, 1972 | Vertical value; LLK |
8.75 ± 0.03 | PE | Klessinger, 1972 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
C7H7+ | 11.8 ± 0.2 | CH3 | EI | Loudon and Mazengo, 1974 | LLK |
C7H7+ | 11.4 ± 0.1 | CH3 | EI | Nounou, 1966 | RDSH |
C7H7+ | 11.3 ± 0.1 | CH3 | PI | Akopyan and Vilesov, 1966 | RDSH |
C8H9+ | 12.3 ± 0.2 | H | EI | Loudon and Mazengo, 1974 | LLK |
C8H9+ | 11.7 ± 0.1 | H | PI | Akopyan and Vilesov, 1966 | RDSH |
C8H9+ | 11.8 ± 0.1 | H | EI | Tait, Shannon, et al., 1962 | RDSH |
De-protonation reactions
C8H9- + =
By formula: C8H9- + H+ = C8H10
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 381.0 ± 2.6 | kcal/mol | G+TS | Caldwell and Bartmess | gas phase; value altered from reference due to change in acidity scale; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 373.9 ± 2.5 | kcal/mol | IMRE | Caldwell and Bartmess | gas phase; value altered from reference due to change in acidity scale; B |
Ion clustering 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:
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
B - John E. Bartmess
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.
Clustering reactions
By formula: C3H9Si+ + C8H10 = (C3H9Si+ • C8H10)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 29.0 | kcal/mol | PHPMS | Wojtyniak and Stone, 1986 | gas phase; switching reaction,Thermochemical ladder((CH3)3Si+)C6H6, Entropy change calculated or estimated; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 35.1 | cal/mol*K | N/A | Wojtyniak and Stone, 1986 | gas phase; switching reaction,Thermochemical ladder((CH3)3Si+)C6H6, Entropy change calculated or estimated; M |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
12.7 | 468. | PHPMS | Wojtyniak and Stone, 1986 | gas phase; switching reaction,Thermochemical ladder((CH3)3Si+)C6H6, Entropy change calculated or estimated; M |
By formula: C9H12+ + C8H10 = (C9H12+ • C8H10)
Bond type: Charge transfer bond (positive ion)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 14.3 | kcal/mol | PHPMS | Meot-Ner (Mautner), Hamlet, et al., 1978 | gas phase; Entropy change calculated or estimated; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 27. | cal/mol*K | N/A | Meot-Ner (Mautner), Hamlet, et al., 1978 | gas phase; Entropy change calculated or estimated; M |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
6.2 | 300. | PHPMS | Meot-Ner (Mautner), Hamlet, et al., 1978 | gas phase; Entropy change calculated or estimated; M |
By formula: Cl- + C8H10 = (Cl- • C8H10)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrG° | 3.90 | kcal/mol | TDEq | French, Ikuta, et al., 1982 | gas phase; B |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
4.4 | 300. | PHPMS | French, Ikuta, et al., 1982 | gas phase; M |
References
Go To: Top, Condensed phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Prosen, Johnson, et al., 1946
Prosen, E.J.; Johnson, W.H.; Rossini, F.D.,
Heats of combustion and formation at 25°C of the alkylbenzenes through C10H14, and of the higher normal monoalkylbenzenes,
J. Res. NBS, 1946, 36, 455-461. [all data]
Coops, Mulder, et al., 1946
Coops, J.; Mulder, D.; Dienske, J.W.; Smittenberg, J.,
The heats of combustion of a number of hydrocarbons,
Rec. Trav. Chim. Pays/Bas, 1946, 65, 128. [all data]
Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]
Richards and Barry, 1915
Richards, T.W.; Barry, F.,
The heats of combustion of aromatic hydrocarbons and hexamethylene,
J. Am. Chem. Soc., 1915, 37, 993-1020. [all data]
Richards and Jesse, 1910
Richards, T.W.; Jesse, R.H., Jr.,
The heats of combustion of the octanes and xylenes,
J. Am. Chem. Soc., 1910, 32, 268-298. [all data]
Pitzer and Scott, 1943
Pitzer, K.S.; Scott, D.W.,
The thermodynamics and molecular structure of benzene and its methyl derivatives,
J. Am. Chem. Soc., 1943, 65, 803-829. [all data]
Huffman, Parks, et al., 1930
Huffman, H.M.; Parks, G.S.; Daniels, A.C.,
Thermal data on organic compounds. VII. The heat capacities, entropies and free energies of twelve aromatic hydrocarbons,
J. Am. Chem. Soc., 1930, 52, 1547-1558. [all data]
Grolier, Roux-Desgranges, et al., 1993
Grolier, J.-P.E.; Roux-Desgranges, G.; Berkane, M.; Jimenez, E.; Wilhelm, E.,
Heat capacities and densities of mixtures of very polar substances 2. Mixtures containing N,N-dimethylformamide,
J. Chem. Thermodynam., 1993, 25(1), 41-50. [all data]
Fortier and Benson, 1979
Fortier, J.-L.; Benson, G.C.,
Heat capacities of some binary aromatic hydrocarbon mixtures containing benzene or toluene,
J. Chem. Eng. Data, 1979, 24(1), 34-37. [all data]
Fortier and Benson, 1977
Fortier, J.-L.; Benson, G.C.,
Excess heat capacities of binary mixtures of tetrachloromethane witlh some aromatic liquids at 298.15 K,
J. Chem. Thermodynam., 1977, 9, 1181-1188. [all data]
Swietoslawski and Zielenkiewicz, 1958
Swietoslawski, W.; Zielenkiewicz, A.,
Mean specific heats of binary positive azeotropes,
Bull. Acad. Pol. Sci. Ser. Sci. Chim., 1958, 6, 367-369. [all data]
Kurbatov, 1947
Kurbatov, V.Ya.,
Specific heat of liquids. I. Specific heat of benzenoid hydrocarbons,
Zhur. Obshch. Khim., 1947, 17, 1999-2003. [all data]
Willams and Daniels, 1924
Willams, J.W.; Daniels, F.,
The specific heats of certain organic liquids at elevated temperatures,
J. Am. Chem. Soc., 1924, 46, 903-917. [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]
Aue, Guidoni, et al., 2000
Aue, D.H.; Guidoni, M.; Betowski, L.D.,
Ab initio calculated gas-phase basicities of polynuclear aromatic hydrocarbons,
Int. J. Mass Spectrom., 2000, 201, 283. [all data]
Fernandez, Jennings, et al., 1989
Fernandez, T.; Jennings, K.R.; Mason, R.S.,
Gas-phase proton transfer reactions in xylene-dimethyl ether mixtures,
J. Chem. Soc. Faraday Trans. 2, 1989, 85, 1813. [all data]
Howell, Goncalves, et al., 1984
Howell, J.O.; Goncalves, J.M.; Amatore, C.; Klasinc, L.; Wightman, R.M.; Kochi, J.K.,
Electron transfer from aromatic hydrocarbons and their π-complexes with metals. Comparison of the standard oxidation potentials and vertical ionization potentials,
J. Am. Chem. Soc., 1984, 106, 3968. [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]
Loudon and Mazengo, 1974
Loudon, A.G.; Mazengo, R.Z.,
Steric strain and electron-impact. The behaviour of some n, n'-dimethyl- 1,1-binaphthyls, some n, n'-dimethylbiphenyls and model compounds,
Org. Mass Spectrom., 1974, 8, 179. [all data]
Maier and Turner, 1973
Maier, J.P.; Turner, D.W.,
Steric inhibition of resonance studied by molecular photoelectron spectroscopy. Part 2. Phenylethylenes,
J. Chem. Soc. Faraday Trans. 2, 1973, 69, 196. [all data]
Akopyan and Vilesov, 1966
Akopyan, M.E.; Vilesov, F.I.,
A mass-spectrometric study of the photo-ionisation of benzene derivatives at wavelengths up to 885 A,
Zh. Fiz. Khim., 1966, 40, 125, In original 63. [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]
Watanabe, 1957
Watanabe, K.,
Ionization potentials of some molecules,
J. Chem. Phys., 1957, 26, 542. [all data]
Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S.,
Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules
in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]
Koenig, Tuttle, et al., 1974
Koenig, T.; Tuttle, M.; Wielesek, R.A.,
The He(I) photoelectron spectra of xylenes and metacyclophanes. A reassignment of the lowest ionic state of [2.2] metacyclophane,
Tetrahedron Lett., 1974, 2537. [all data]
Kobayashi and Nagakura, 1972
Kobayashi, T.; Nagakura, S.,
Photoelectron spectra of nitro-compounds,
Chem. Lett., 1972, 903. [all data]
Klessinger, 1972
Klessinger, M.,
Ionization potentials of substituted benzenes,
Angew. Chem. Int. Ed. Engl., 1972, 11, 525. [all data]
Nounou, 1966
Nounou, P.,
Etude des composes aromatiques par spectrometrie de masse. I. Mesure des potentials d'ionisation et d'apparition par la methode du potential retardateur et interpretation des courbes d'ionisation differentielle,
J. Chim. Phys., 1966, 63, 994. [all data]
Tait, Shannon, et al., 1962
Tait, J.M.S.; Shannon, T.W.; Harrison, A.G.,
The structure of substituted C7 ions from benzyl derivatives at the appearance potential threshold,
J. Am. Chem. Soc., 1962, 84, 4. [all data]
Caldwell and Bartmess
Caldwell, G.; Bartmess, J.E.,
, Unpublished results. [all data]
Wojtyniak and Stone, 1986
Wojtyniak, A.C.M.; Stone, A.J.,
A High-Pressure Mass Spectrometric Study of the Bonding of Trimethylsilylium to Oxygen and Aromatic Bases,
Can. J. Chem., 1986, 74, 59. [all data]
Meot-Ner (Mautner), Hamlet, et al., 1978
Meot-Ner (Mautner), M.; Hamlet, P.; Hunter, E.P.; Field, F.H.,
Bonding Energies in Association Ions of Aromatic Molecules. Correlations with Ionization Energies,
J. Am. Chem. Soc., 1978, 100, 17, 5466, https://doi.org/10.1021/ja00485a034
. [all data]
French, Ikuta, et al., 1982
French, M.A.; Ikuta, S.; Kebarle, P.,
Hydrogen bonding of O-H and C-H hydrogen donors to Cl-. Results from mass spectrometric measurement of the ion-molecule equilibria RH + Cl- = RHCl-,
Can. J. Chem., 1982, 60, 1907. [all data]
Notes
Go To: Top, Condensed phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, References
- Symbols used in this document:
AE Appearance energy Cp,liquid Constant pressure heat capacity of liquid IE (evaluated) Recommended ionization energy S°liquid Entropy of liquid at standard conditions T Temperature ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔfH°liquid Enthalpy of formation of liquid 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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