o-Xylene
- Formula: C8H10
- Molecular weight: 106.1650
- IUPAC Standard InChIKey: CTQNGGLPUBDAKN-UHFFFAOYSA-N
- CAS Registry Number: 95-47-6
- 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. - Isotopologues:
- Other names: Benzene, 1,2-dimethyl-; o-Dimethylbenzene; o-Methyltoluene; o-Xylol; 1,2-Dimethylbenzene; 1,2-Xylene; 3,4-Xylene; ortho-Xylene; NSC 60920; 2-Methyltoluene; UN 1307; 1,2-dimethyl-benzene ( o-xylene)
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Condensed phase thermochemistry data
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics 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 | -5.84 ± 0.26 | kcal/mol | Ccb | Prosen, Gilmont, et al., 1945 | Hf by Prosen, Johnson, et al., 1946; ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°liquid | -1087.83 ± 0.12 | kcal/mol | Cm | Coops, Mulder, et al., 1946 | Reanalyzed by Cox and Pilcher, 1970, Original value = -1087.40 ± 0.12 kcal/mol; Corresponding ΔfHºliquid = -6.15 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
ΔcH°liquid | -1088.16 ± 0.24 | kcal/mol | Ccb | Prosen, Gilmont, et al., 1945 | Hf by Prosen, Johnson, et al., 1946; Corresponding ΔfHºliquid = -5.82 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 | 58.800 | cal/mol*K | N/A | Pitzer and Scott, 1943 | DH |
S°liquid | 59.30 | cal/mol*K | N/A | Huffman, Parks, et al., 1930 | Extrapolation below 90 K, 60.79 J/mol*K.; DH |
Constant pressure heat capacity of liquid
Cp,liquid (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
44.8501 | 298.15 | Fortier and Benson, 1979 | DH |
44.8337 | 298.15 | Fortier and Benson, 1977 | DH |
49.40 | 347. | Swietoslawski and Zielenkiewicz, 1958 | Mean value 22 to 126 C.; DH |
44.69 | 298. | Kurbatov, 1947 | T = 15 to 132 C, mean Cp, three temperatures.; DH |
44.890 | 298.15 | Pitzer and Scott, 1943 | T = 14 to 301 K.; DH |
43.951 | 298.1 | Huffman, Parks, et al., 1930 | T = 90 to 295 K. Value is unsmoothed experimental datum.; DH |
43.59 | 303. | Willams and Daniels, 1924 | T = 303 to 348 K. Equation only.; DH |
Reaction thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Gas phase ion energetics 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:
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
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
By formula: C3H9Si+ + C8H10 = (C3H9Si+ • C8H10)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 29.1 | 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: C3H9Sn+ + C8H10 = (C3H9Sn+ • C8H10)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 29.9 | kcal/mol | PHPMS | Stone and Splinter, 1984 | gas phase; switching reaction((CH3)3Sn+)CH3OH, Entropy change calculated or estimated; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 31.8 | cal/mol*K | N/A | Stone and Splinter, 1984 | gas phase; switching reaction((CH3)3Sn+)CH3OH, Entropy change calculated or estimated; M |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
13.2 | 525. | PHPMS | Stone and Splinter, 1984 | gas phase; switching reaction((CH3)3Sn+)CH3OH, Entropy change calculated or estimated; M |
By formula: 3H2 + C8H10 = C8H16
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -46.51 ± 0.20 | kcal/mol | Chyd | Dolliver, Gresham, et al., 1937 | gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -47.25 ± 0.20 kcal/mol; At 355 °K; ALS |
Gas phase ion energetics data
Go To: Top, Condensed 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:
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) | 8.56 ± 0.04 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
Proton affinity (review) | 190.2 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 183.6 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Proton affinity at 298K
Proton affinity (kcal/mol) | Reference | Comment |
---|---|---|
189.1 | Aue, Guidoni, et al., 2000 | Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM |
189.7 ± 0.41 | 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 |
---|---|---|
182.9 | Aue, Guidoni, et al., 2000 | Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM |
184.5 ± 0.53 | 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 |
---|---|---|
8.82 | 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 ± 0.01 | EQ | Lias and Ausloos, 1978 | LLK |
8.85 ± 0.05 | EI | Loudon and Mazengo, 1974 | LLK |
8.45 ± 0.02 | PE | Maier and Turner, 1973 | LLK |
8.70 | CTS | Kobayashi, Kobayashi, et al., 1973 | LLK |
8.6 ± 0.1 | EI | Gilbert, Leach, et al., 1973 | LLK |
8.61 | CTS | Pitt, 1970 | RDSH |
8.555 | PI | Bralsford, Harris, et al., 1960 | RDSH |
8.56 ± 0.01 | PI | Watanabe, 1957 | RDSH |
8.56 ± 0.02 | PI | Vilesov and Terenin, 1957 | RDSH |
8.58 ± 0.01 | S | Hammond, Price, et al., 1950 | RDSH |
8.56 | PE | Howell, Goncalves, et al., 1984 | Vertical value; LBLHLM |
8.57 ± 0.03 | PE | Heilbronner, Hoshi, et al., 1976 | Vertical value; LLK |
8.57 | PE | Brogli, Giovannini, et al., 1973 | 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+ | 11.10 ± 0.05 | CH3 | PI | Akopyan and Vilesov, 1968 | RDSH |
C7H7+ | 11.2 ± 0.1 | CH3 | EI | Nounou, 1966 | RDSH |
C8H9+ | 12.1 ± 0.2 | H | EI | Loudon and Mazengo, 1974 | LLK |
C8H9+ | 11.30 ± 0.05 | H | PI | Akopyan and Vilesov, 1968 | RDSH |
References
Go To: Top, Condensed 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.
Prosen, Gilmont, et al., 1945
Prosen, E.J.; Gilmont, R.; Rossini, F.D.,
Heats of combustion of benzene, toluene, ethyl-benzene, o-xylene, m-xylene, p-xylene, n-propylbenzene, and styrene,
J. Res. NBS, 1945, 34, 65-70. [all data]
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]
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]
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]
Stone and Splinter, 1984
Stone, J.A.; Splinter, D.E.,
A high-pressure mass spectrometric study of the binding of (CH3)3Sn+ to lewis bases in the gas phase,
Int. J. Mass Spectrom. Ion Processes, 1984, 59, 169. [all data]
Dolliver, Gresham, et al., 1937
Dolliver, M.a.; Gresham, T.L.; Kistiakowsky, G.B.; Vaughan, W.E.,
Heats of organic reactions. V. Heats of hydrogenation of various hydrocarbons,
J. Am. Chem. Soc., 1937, 59, 831-841. [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]
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]
Kobayashi, Kobayashi, et al., 1973
Kobayashi, H.; Kobayashi, M.; Kaizu, Y.,
Molecular complexes of arenetricarbonylchromium,
Bull. Chem. Soc. Jpn., 1973, 46, 3109. [all data]
Gilbert, Leach, et al., 1973
Gilbert, J.R.; Leach, W.P.; Miller, J.R.,
Ionisation appearance potential measurements in arene chromium tricarbonyls,
J. Organomet. Chem., 1973, 49, 219. [all data]
Pitt, 1970
Pitt, C.G.,
Hyperconjugation: An alternative to the concept of the pπ-dπ bond in Group IV chemistry,
J. Organomet. Chem., 1970, 23, 35. [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]
Vilesov and Terenin, 1957
Vilesov, F.I.; Terenin, A.N.,
The photoionization of the vapors of certain organic compounds,
Dokl. Akad. Nauk SSSR, 1957, 115, 744, In original 539. [all data]
Hammond, Price, et al., 1950
Hammond, V.J.; Price, W.C.; Teegan, J.P.; Walsh, A.D.,
The absorption spectra of some substituted benzenes and naphthalenes in the vacuum ultra-violet,
Faraday Discuss. Chem. Soc., 1950, 9, 53. [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]
Heilbronner, Hoshi, et al., 1976
Heilbronner, E.; Hoshi, T.; von Rosenberg, J.L.; Hafner, K.,
Alkyl-induced, natural hypsochromic shifts of the 2A←2X and 2B←2X transitions of azulene and naphthalene radical cations,
Nouv. J. Chim., 1976, 1, 105. [all data]
Brogli, Giovannini, et al., 1973
Brogli, F.; Giovannini, E.; Heilbronner, E.; Schurter, R.,
Die photoelektronen spektren der benzocycloalkene,
Chem. Ber., 1973, 106, 961. [all data]
Klessinger, 1972
Klessinger, M.,
Ionization potentials of substituted benzenes,
Angew. Chem. Int. Ed. Engl., 1972, 11, 525. [all data]
Akopyan and Vilesov, 1968
Akopyan, M.E.; Vilesov, F.I.,
Mass-spectrometric investigation of the photo-ionization of benzene and its methyl derivatives,
Khim. Vysokikh Energ., 1968, 2, 107, In original 89. [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]
Notes
Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics 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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