Benzene, 1,3-dimethyl-

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.


Gas phase thermochemistry data

Go To: Top, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), 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
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity Value Units Method Reference Comment
Δfgas4.12 ± 0.18kcal/molCcbProsen, Johnson, et al., 1946ALS
Quantity Value Units Method Reference Comment
gas85.60 ± 0.30cal/mol*KN/APitzer K.S., 1943GT

Constant pressure heat capacity of gas

Cp,gas (cal/mol*K) Temperature (K) Reference Comment
20.84200.Draeger, 1985Discrepancies with other statistically calculated values of S(T) and Cp(T) [ Pitzer K.S., 1943, Taylor W.J., 1946, Hastings S.H., 1957, Chao J., 1984] do not exceed 1.5 J/mol*K.; GT
27.63273.15
30.07 ± 0.1298.15
30.26300.
39.94400.
48.49500.
55.64600.
61.59700.
66.59800.
70.79900.
74.381000.
77.461100.
80.091200.
82.361300.
84.321400.
85.991500.

Constant pressure heat capacity of gas

Cp,gas (cal/mol*K) Temperature (K) Reference Comment
39.10 ± 0.40393.Taylor W.J., 1946Please also see Pitzer K.S., 1943.; GT
42.40 ± 0.40428.
45.40 ± 0.40463.

Phase change data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Mass spectrum (electron ionization), 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:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
BS - Robert L. Brown and Stephen E. Stein
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Tboil412.3 ± 0.3KAVGN/AAverage of 39 out of 42 values; Individual data points
Quantity Value Units Method Reference Comment
Tfus225. ± 4.KAVGN/AAverage of 8 values; Individual data points
Quantity Value Units Method Reference Comment
Ttriple219.6KN/AHuffman, Parks, et al., 1930Uncertainty assigned by TRC = 0.3 K; TRC
Quantity Value Units Method Reference Comment
Tc618. ± 4.KAVGN/AAverage of 9 values; Individual data points
Quantity Value Units Method Reference Comment
Pc34.9 ± 0.4atmN/ATsonopoulos and Ambrose, 1995 
Pc34.949atmN/AAmbrose, 1987Uncertainty assigned by TRC = 0.05 atm; TRC
Pc34.95atmN/AAmbrose, Broderick, et al., 1967Uncertainty assigned by TRC = 0.06 atm; TRC
Pc33.0000atmN/AGlaser and Ruland, 1957Uncertainty assigned by TRC = 1.5000 atm; TRC
Pc34.64atmN/AAltschul, 1893Uncertainty assigned by TRC = 0.0387 atm; TRC
Quantity Value Units Method Reference Comment
Vc0.375l/molN/ATsonopoulos and Ambrose, 1995 
Quantity Value Units Method Reference Comment
ρc2.67 ± 0.04mol/lN/ATsonopoulos and Ambrose, 1995 
ρc2.684mol/lN/AAkhundov and Asadullaeva, 1968Uncertainty assigned by TRC = 0.05 mol/l; TRC
Quantity Value Units Method Reference Comment
Δvap10. ± 1.kcal/molAVGN/AAverage of 8 values; Individual data points

Enthalpy of vaporization

ΔvapH (kcal/mol) Temperature (K) Method Reference Comment
8.523412.3N/AMajer and Svoboda, 1985 
9.37375.N/ASwiatek and Malanowski, 2002Based on data from 360. to 410. K.; AC
9.73342.N/APark and Gmehling, 1989Based on data from 327. to 412. K.; AC
10.7282.AStephenson and Malanowski, 1987Based on data from 267. to 301. K.; AC
8.96427.AStephenson and Malanowski, 1987Based on data from 412. to 462. K.; AC
8.70476.AStephenson and Malanowski, 1987Based on data from 461. to 554. K.; AC
8.65565.AStephenson and Malanowski, 1987Based on data from 550. to 617. K.; AC
9.66346.MMStephenson and Malanowski, 1987Based on data from 331. to 415. K. See also Willingham, Taylor, et al., 1945 and Forziati, Norris, et al., 1949.; AC
9.25395.N/AMachat, 1983Based on data from 380. to 411. K.; AC
10.3288.N/APitzer and Scott, 1943Based on data from 273. to 333. K. See also Boublik, Fried, et al., 1984.; AC

Antoine Equation Parameters

log10(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Temperature (K) A B C Reference Comment
332.4 to 413.194.130361463.218-57.991Williamham, Taylor, et al., 1945Coefficents calculated by NIST from author's data.
273. to 333.5.086281996.545-14.772Pitzer and Scott, 1943Coefficents calculated by NIST from author's data.

Enthalpy of fusion

ΔfusH (kcal/mol) Temperature (K) Reference Comment
2.7651225.27Pitzer and Scott, 1943DH
2.770225.3Domalski and Hearing, 1996AC

Entropy of fusion

ΔfusS (cal/mol*K) Temperature (K) Reference Comment
12.28225.27Pitzer and Scott, 1943DH

Enthalpy of phase transition

ΔHtrs (kcal/mol) Temperature (K) Initial Phase Final Phase Reference Comment
0.0497166.crystaline, IIcrystaline, IHuffman, Parks, et al., 1930, 2DH
2.7349219.6crystaline, IliquidHuffman, Parks, et al., 1930, 2DH

Entropy of phase transition

ΔStrs (cal/mol*K) Temperature (K) Initial Phase Final Phase Reference Comment
0.299166.crystaline, IIcrystaline, IHuffman, Parks, et al., 1930, 2DH
12.45219.6crystaline, IliquidHuffman, Parks, et al., 1930, 2DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, Mass spectrum (electron ionization), 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
B - John E. Bartmess

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

C3H9Si+ + Benzene, 1,3-dimethyl- = (C3H9Si+ • Benzene, 1,3-dimethyl-)

By formula: C3H9Si+ + C8H10 = (C3H9Si+ • C8H10)

Quantity Value Units Method Reference Comment
Δr29.0kcal/molPHPMSWojtyniak and Stone, 1986gas phase; switching reaction,Thermochemical ladder((CH3)3Si+)C6H6, Entropy change calculated or estimated; M
Quantity Value Units Method Reference Comment
Δr35.1cal/mol*KN/AWojtyniak and Stone, 1986gas 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
12.7468.PHPMSWojtyniak and Stone, 1986gas phase; switching reaction,Thermochemical ladder((CH3)3Si+)C6H6, Entropy change calculated or estimated; M

C9H12+ + Benzene, 1,3-dimethyl- = (C9H12+ • Benzene, 1,3-dimethyl-)

By formula: C9H12+ + C8H10 = (C9H12+ • C8H10)

Bond type: Charge transfer bond (positive ion)

Quantity Value Units Method Reference Comment
Δr14.3kcal/molPHPMSMeot-Ner (Mautner), Hamlet, et al., 1978gas phase; Entropy change calculated or estimated; M
Quantity Value Units Method Reference Comment
Δr27.cal/mol*KN/AMeot-Ner (Mautner), Hamlet, et al., 1978gas phase; Entropy change calculated or estimated; M

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
6.2300.PHPMSMeot-Ner (Mautner), Hamlet, et al., 1978gas phase; Entropy change calculated or estimated; M

C8H9- + Hydrogen cation = Benzene, 1,3-dimethyl-

By formula: C8H9- + H+ = C8H10

Quantity Value Units Method Reference Comment
Δr381.0 ± 2.6kcal/molG+TSCaldwell and Bartmessgas phase; value altered from reference due to change in acidity scale; B
Quantity Value Units Method Reference Comment
Δr373.9 ± 2.5kcal/molIMRECaldwell and Bartmessgas phase; value altered from reference due to change in acidity scale; B

Chlorine anion + Benzene, 1,3-dimethyl- = (Chlorine anion • Benzene, 1,3-dimethyl-)

By formula: Cl- + C8H10 = (Cl- • C8H10)

Quantity Value Units Method Reference Comment
Δr3.90kcal/molTDEqFrench, Ikuta, et al., 1982gas phase; B

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
4.4300.PHPMSFrench, Ikuta, et al., 1982gas phase; M

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Phase change 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 compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

Mass spectrum
For Zoom
1.) Enter the desired X axis range (e.g., 100, 200)
2.) Check here for automatic Y scaling
3.) Press here to zoom

Additional Data

View image of digitized spectrum (can be printed in landscape orientation).

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 NIST Mass Spectrometry Data Center, 1998.
NIST MS number 291455

All mass spectra in this site (plus many more) are available from the NIST/EPA/NIH Mass Spectral Library. Please see the following for information about the library and its accompanying search program.


References

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), 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]

Pitzer K.S., 1943
Pitzer K.S., The thermodynamics and molecular structure of benzene and its methyl derivatives, J. Am. Chem. Soc., 1943, 65, 803-829. [all data]

Draeger, 1985
Draeger, J.A., The methylbenzenes II. Fundamental vibrational shifts, statistical thermodynamic functions, and properties of formation, J. Chem. Thermodyn., 1985, 17, 263-275. [all data]

Taylor W.J., 1946
Taylor W.J., Heats, equilibrium constants, and free energies of formation of the alkylbenzenes, J. Res. Nat. Bur. Stand., 1946, 37, 95-122. [all data]

Hastings S.H., 1957
Hastings S.H., Thermodynamic properties of selected methylbenzenes from 0 to 1000 K, J. Phys. Chem., 1957, 61, 730-735. [all data]

Chao J., 1984
Chao J., Chemical thermodynamic properties of toluene, o-, m- and p-xylenes, Thermochim. Acta, 1984, 72, 323-334. [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, 1547-58. [all data]

Tsonopoulos and Ambrose, 1995
Tsonopoulos, C.; Ambrose, D., Vapor-Liquid Critical Properties of Elements and Compounds. 3. Aromatic Hydrocarbons, J. Chem. Eng. Data, 1995, 40, 547-558. [all data]

Ambrose, 1987
Ambrose, D., Vapor Pressures of Some Aromatic Hydrocarbons, J. Chem. Thermodyn., 1987, 19, 1007. [all data]

Ambrose, Broderick, et al., 1967
Ambrose, D.; Broderick, B.E.; Townsend, R., The Vapour Pressures above the Normal Boiling Point and the Critical Pressures of Some Aromatic Hydrocarbons, J. Chem. Soc. , 1967, 1967, 1967, 633-41. [all data]

Glaser and Ruland, 1957
Glaser, F.; Ruland, H., Untersuchungsen über dampfdruckkurven und kritische daten einiger technisch wichtiger organischer substanzen, Chem. Ing. Techn., 1957, 29, 772. [all data]

Altschul, 1893
Altschul, M., The critical values of some organic compounds, Z. Phys. Chem., Stoechiom. Verwandtschaftsl., 1893, 11, 577. [all data]

Akhundov and Asadullaeva, 1968
Akhundov, T.S.; Asadullaeva, N.N., Specific volumes of m-xylene near the critical point, Izv. Vyssh. Uchebn. Zaved., Neft Gaz, 1968, 11, 6, 836. [all data]

Majer and Svoboda, 1985
Majer, V.; Svoboda, V., Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation, Blackwell Scientific Publications, Oxford, 1985, 300. [all data]

Swiatek and Malanowski, 2002
Swiatek, Barbara E.; Malanowski, Stanislaw K., Vapor-Liquid Equilibrium in m -Xylene + Cyclohexanol at 19.99 and 94.93 kPa, J. Chem. Eng. Data, 2002, 47, 3, 478-481, https://doi.org/10.1021/je010246z . [all data]

Park and Gmehling, 1989
Park, So Jin; Gmehling, Juergen, Isobaric vapor-liquid equilibrium data for the binary systems 1,3,5-trimethylbenzene/N-formylmorpholine and m-xylene/N-formylmorpholine, J. Chem. Eng. Data, 1989, 34, 4, 399-401, https://doi.org/10.1021/je00058a008 . [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Willingham, Taylor, et al., 1945
Willingham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D., Vapor pressures and boiling points of some paraffin, alkylcyclopentane, alkylcyclohexane, and alkylbenzene hydrocarbons, J. RES. NATL. BUR. STAN., 1945, 35, 3, 219-17, https://doi.org/10.6028/jres.035.009 . [all data]

Forziati, Norris, et al., 1949
Forziati, Alphonse F.; Norris, William R.; Rossini, Frederick D., Vapor pressures and boiling points of sixty API-NBS hydrocarbons, J. RES. NATL. BUR. STAN., 1949, 43, 6, 555-17, https://doi.org/10.6028/jres.043.050 . [all data]

Machat, 1983
Machat, V., , Thesis, Utzcht, Prague, 1983. [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]

Boublik, Fried, et al., 1984
Boublik, T.; Fried, V.; Hala, E., The Vapour Pressures of Pure Substances: Selected Values of the Temperature Dependence of the Vapour Pressures of Some Pure Substances in the Normal and Low Pressure Region, 2nd ed., Elsevier, New York, 1984, 972. [all data]

Williamham, Taylor, et al., 1945
Williamham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D., Vapor Pressures and Boiling Points of Some Paraffin, Alkylcyclopentane, Alkylcyclohexane, and Alkylbenzene Hydrocarbons, J. Res. Natl. Bur. Stand. (U.S.), 1945, 35, 3, 219-244, https://doi.org/10.6028/jres.035.009 . [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

Huffman, Parks, et al., 1930, 2
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]

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]

Caldwell and Bartmess
Caldwell, G.; Bartmess, J.E., , Unpublished results. [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, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), References