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3,5-Dimethylpyrazole

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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

Quantity Value Units Method Reference Comment
Tboil491.2KN/AWeast and Grasselli, 1989BS
Quantity Value Units Method Reference Comment
Deltasub83.4 ± 2.4kJ/molCRibeiro da Silva, Ferreira, et al., 2001AC

Enthalpy of sublimation

DeltasubH (kJ/mol) Temperature (K) Method Reference Comment
83.3 ± 0.2301.MEElguero, Yranzo, et al., 1991AC

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 by: 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

C5H7N2- + Hydrogen cation = 3,5-Dimethylpyrazole

By formula: C5H7N2- + H+ = C5H8N2

Quantity Value Units Method Reference Comment
Deltar1480. ± 8.8kJ/molG+TSTaft, 1987gas phase; value altered from reference due to change in acidity scale
Quantity Value Units Method Reference Comment
Deltar1450. ± 8.4kJ/molIMRETaft, 1987gas phase; value altered from reference due to change in acidity scale

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

Quantity Value Units Method Reference Comment
Proton affinity (review)933.5kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity900.1kJ/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
8.75 ± 0.03PELichtenberger, Copenhaver, et al., 1988LL

De-protonation reactions

C5H7N2- + Hydrogen cation = 3,5-Dimethylpyrazole

By formula: C5H7N2- + H+ = C5H8N2

Quantity Value Units Method Reference Comment
Deltar1480. ± 8.8kJ/molG+TSTaft, 1987gas phase; value altered from reference due to change in acidity scale; B
Quantity Value Units Method Reference Comment
Deltar1450. ± 8.4kJ/molIMRETaft, 1987gas phase; value altered from reference due to change in acidity scale; B

IR Spectrum

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Data compiled by: Coblentz Society, Inc.


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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Mass spectrum
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Additional Data

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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 Japan AIST/NIMC Database- Spectrum MS-NW-6290
NIST MS number 234855

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.


UV/Visible 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: Victor Talrose, Alexander N. Yermakov, Alexy A. Usov, Antonina A. Goncharova, Axlexander N. Leskin, Natalia A. Messineva, Natalia V. Trusova, Margarita V. Efimkina

Spectrum

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UVVis spectrum
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Additional Data

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Source Bernarducci, et al., 1981
Owner INEP CP RAS, NIST OSRD
Collection (C) 2007 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
Origin INSTITUTE OF ENERGY PROBLEMS OF CHEMICAL PHYSICS, RAS
Source reference RAS UV No. 18512
Instrument Cary 17

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

Kovats' RI, non-polar column, isothermal

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Column type Active phase Temperature (C) I Reference Comment
CapillaryOV-101110.1010.Golovnya, Kuz'menko, et al., 2000He; Phase thickness: 0.4 «mu»m
CapillaryOV-101110.1010.Zhuravleva, 200050. m/0.3 mm/0.4 «mu»m, He

Van Den Dool and Kratz RI, polar column, temperature ramp

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Column type Active phase I Reference Comment
CapillaryDB-Wax1675.Cha, Kim, et al., 199860. m/0.25 mm/0.25 «mu»m, 40. C @ 5. min, 3. K/min, 200. C @ 60. min

Normal alkane RI, non-polar column, custom temperature program

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Column type Active phase I Reference Comment
CapillaryVF-51024.Shivashankar, Roy, et al., 201230. m/0.25 mm/0.25 «mu»m, Helium; Program: 50 0C (2 min) 3 0C/min -> 200 0C (3 min) 10 0C/min -> 220 0C (8 min)
CapillaryVF-51014.Shivashankar, Roy, et al., 201230. m/0.25 mm/0.25 «mu»m, Helium; Program: not specified

Normal alkane RI, polar column, temperature ramp

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Column type Active phase I Reference Comment
CapillarySupelcowax-101685.Korány, Mednyánszky, et al., 200060. m/0.25 mm/0.25 «mu»m, He, 4. K/min; Tstart: 60. C; Tend: 280. C

References

Go To: Top, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, NIST Free Links, Notes

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]

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]

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]

Bernarducci, et al., 1981
Bernarducci, E., et al., J. Am. Chem. Soc., 1981, 103, 1686. [all data]

Golovnya, Kuz'menko, et al., 2000
Golovnya, R.V.; Kuz'menko, T.E.; Krikunova, N.I., The influence of alkyl substituents on the chromatographic indicator of self-association of N-containing heterocyclic compounds, Russ. Chem. Bull. (Engl. Transl.), 2000, 49, 2, 321-324, https://doi.org/10.1007/BF02494681 . [all data]

Zhuravleva, 2000
Zhuravleva, I.L., Evaluation of the polarity and boiling points of nitrogen-containing heterocyclic compounds by gas chromatography, Russ. Chem. Bull. (Engl. Transl.), 2000, 49, 2, 325-328, https://doi.org/10.1007/BF02494682 . [all data]

Cha, Kim, et al., 1998
Cha, Y.J.; Kim, H.; Cadwallader, K.R., Aroma-active compounds in Kimchi during fermentation, J. Agric. Food Chem., 1998, 46, 5, 1944-1953, https://doi.org/10.1021/jf9706991 . [all data]

Shivashankar, Roy, et al., 2012
Shivashankar, S.; Roy, T.K.; Moorthy, P.N.R., Headspace solid phase micro extraction and GC/MS analysis of the volatile components in seed and cake of Azadirachta indica A. juss, Chem. Bull. of Politechnika Univ. Timisoara, Romania, 2012, 57(71), 1, 1-6. [all data]

Korány, Mednyánszky, et al., 2000
Korány, K.; Mednyánszky, Zs.; Amtmann, M., Preliminary results of a recognition method visualizing the aroma and fragrance features, Acta Aliment., 2000, 29, 2, 187-198, https://doi.org/10.1556/AAlim.29.2000.2.9 . [all data]


Notes

Go To: Top, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, NIST Free Links, References