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)
- IUPAC Standard InChIKey: SDXAWLJRERMRKF-UHFFFAOYSA-N
- 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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Reaction thermochemistry data
Go To: Top, Gas phase ion energetics data, Gas Chromatography, 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: 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- + =
By formula: C5H7N2- + H+ = C5H8N2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 353.8 ± 2.1 | kcal/mol | G+TS | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 346.5 ± 2.0 | kcal/mol | IMRE | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale |
Gas phase ion energetics data
Go To: Top, Reaction thermochemistry data, Gas Chromatography, 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
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) | 223.1 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
| Quantity | Value | Units | Method | Reference | Comment |
| Gas basicity | 215.1 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 8.75 ± 0.03 | PE | Lichtenberger, Copenhaver, et al., 1988 | LL |
De-protonation reactions
C5H7N2- + =
By formula: C5H7N2- + H+ = C5H8N2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 353.8 ± 2.1 | kcal/mol | G+TS | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 346.5 ± 2.0 | kcal/mol | IMRE | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
Gas Chromatography
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 by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Kovats' RI, non-polar column, isothermal
| Column type | Active phase | Temperature (C) | I | Reference | Comment |
|---|---|---|---|---|---|
| Capillary | OV-101 | 110. | 1010. | Golovnya, Kuz'menko, et al., 2000 | He; Phase thickness: 0.4 μm |
| Capillary | OV-101 | 110. | 1010. | Zhuravleva, 2000 | 50. m/0.3 mm/0.4 μm, He |
Van Den Dool and Kratz RI, polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | DB-Wax | 1675. | Cha, Kim, et al., 1998 | 60. m/0.25 mm/0.25 μm, 40. C @ 5. min, 3. K/min, 200. C @ 60. min |
Normal alkane RI, non-polar column, custom temperature program
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | VF-5 | 1024. | Shivashankar, Roy, et al., 2012 | 30. m/0.25 mm/0.25 μm, Helium; Program: 50 0C (2 min) 3 0C/min -> 200 0C (3 min) 10 0C/min -> 220 0C (8 min) |
| Capillary | VF-5 | 1014. | Shivashankar, Roy, et al., 2012 | 30. m/0.25 mm/0.25 μm, Helium; Program: not specified |
Normal alkane RI, polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | Supelcowax-10 | 1685. | Korány, Mednyánszky, et al., 2000 | 60. m/0.25 mm/0.25 μm, He, 4. K/min; Tstart: 60. C; Tend: 280. C |
References
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Gas Chromatography, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
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]
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, Reaction thermochemistry data, Gas phase ion energetics data, Gas Chromatography, References
- Symbols used in this document:
ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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