3,5-Dimethylpyrazole

• Formula: C₅H₈N₂
• Molecular weight: 96.1304
• IUPAC Standard InChI: InChI=1S/C5H8N2/c1-4-3-5(2)7-6-4/h3H,1-2H3,(H,6,7) Copy

  
• IUPAC Standard InChIKey: SDXAWLJRERMRKF-UHFFFAOYSA-N Copy
• CAS Registry Number: 67-51-6
• Chemical structure:
  This structure is also available as a 2d Mol file
• Other names: 1H-Pyrazole, 3,5-dimethyl-; Pyrazole, 3,5-dimethyl-; TH 564; U 6245; 3,5 DMP; 3,5-Dwumetylopirazolu; 3,5-Dimethyl-1H-pyrazole; 1(H)-3,5-Dimethylpyrazole; NSC 8729
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• Information on this page:
  • Phase change data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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Phase change 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:
BS - Robert L. Brown and Stephen E. Stein
AC - William E. Acree, Jr., James S. Chickos

Enthalpy of sublimation

Gas phase ion energetics 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 evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LL - Sharon G. Lias and Joel F. Liebman

Ionization energy determinations

De-protonation reactions

C₅H₇N₂^- +  =

By formula: C₅H₇N₂^- + H⁺ = C₅H₈N₂

References

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]

Ribeiro da Silva, Ferreira, et al., 2001
Ribeiro da Silva, Maria D.M.C.; Ferreira, Susana C.C.; Rodrigues, Ivone A.P.; da Silva, Luís C.M.; Acree Jr, William E.; Pandey, Siddharth; Roy, Lindsay E., Experimental standard molar enthalpies of formation of crystalline 3,5-dimethylpyrazole, 3,5-dimethyl-4-nitrosopyrazole, 1,3,5-trimethyl-4-nitrosopyrazole, and 3,5-dimethyl-1-phenyl-4-nitrosopyrazole, The Journal of Chemical Thermodynamics, 2001, 33, 10, 1227-1235, https://doi.org/10.1006/jcht.2000.0768 . [all data]

Elguero, Yranzo, et al., 1991
Elguero, Jose; Yranzo, Gloria I.; Laynez, Jose; Jimenez, Pilar; Menendez, Margarita; Catalan, Javier; De Paz, Jose Luis G.; Anvia, Frederick; Taft, Robert W., Effect of the replacement of a methyl by a trifluoromethyl group on the acid-base properties of pyrazoles, J. Org. Chem., 1991, 56, 12, 3942-3947, https://doi.org/10.1021/jo00012a030 . [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]

Lichtenberger, Copenhaver, et al., 1988
Lichtenberger, D.L.; Copenhaver, A.S.; Gray, H.B.; Marshall, J.L.; Hopkins, M.D., Valence electronic structure of bis(Pyrazolyl)-bridged iridium dicarbonyl dimers. Electronic effects of 3,5-dimethylpyraxzolyl substitution on metal-metal interactions, Inorg. Chem., 1988, 27, 4488. [all data]

Taft, 1987
Taft, R.W., The Nature and Analysis of Substitutent Electronic Effects, Personal communication. See also Prog. Phys. Org. Chem., 1987, 16, 1. [all data]

Notes

Go To: Top, Phase change data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  Tboil	Boiling point
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔsubH	Enthalpy of sublimation
  ΔsubH°	Enthalpy of sublimation at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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