Caffeine
- Formula: C8H10N4O2
- Molecular weight: 194.1906
- IUPAC Standard InChI: InChI=1S/C8H10N4O2/c1-10-4-9-6-5(10)7(13)12(3)8(14)11(6)2/h4H,1-3H3
- IUPAC Standard InChIKey: RYYVLZVUVIJVGH-UHFFFAOYSA-N
- CAS Registry Number: 58-08-2
- 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. - Other names: 1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl-; Alert-Pep; Cafeina; Caffein; Caffine; Cafipel; Coffeine; Guaranine; Koffein; Mateina; Methyltheobromine; No-Doz; Refresh'n; Stim; Thein; Theine; 1,3,7-Trimethyl-2,6-dioxopurine; 1,3,7-Trimethylxanthine; Cafamil; Cafecon; Caffeine, synthetic; Eldiatric C; Nix Nap; Nodaca; NCI-C02733; Theobromine, 1-methyl-; Theophylline, 7-methyl; Xanthine, 1,3,7-trimethyl; 3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione; Coffein; Kofein; Organex; Monomethyl derivative of Theophylline; Theobromine Me; Theophylline Me; Caffedrine; Hycomine; NSC 5036; Tri-Aqua; Wigraine; 7-Methylxanthine, N,N'-dimethyl-; 1,3,7-Trimethyl-3,7-dihydro-1H-purine-2,6-dione; A.S.A. and Codeine Compound; Anacin; Anacin Maximum Strength; Bayer Select Headache Pain; Cafergot; DHCplus; Dasin; Fiorinal; Hycomine Compound; Midol Maximum Strength; Norgesic; P-A-C Analgesic Tablets; Phensal; Propoxyphene Compound 65; SK-65 Compound; Synalgos; Synalgos-DC; Vanquish; component of A.S.A. Compound; component of Ansemco 2; component of Dilone; component of Midol; component of P-A-C Compound; component of Percodan; 71701-02-5; 95789-13-2; A.S.A. and Codeine Compound (Salt/Mix); Anacin (Salt/Mix); Anacin Maximum Strength (Salt/Mix); Bayer Select Headache Pain (Salt/Mix); Cafergot (Salt/Mix); DHCplus (Salt/Mix); Dasin (Salt/Mix); Fiorinal (Salt/Mix); Hycomine Compound (Salt/Mix); Midol Maximum Strength (Salt/Mix); Norgesic (Salt/Mix); P-A-C Analgesic Tablets (Salt/Mix); Phensal (Salt/Mix); Propoxyphene Compound 65 (Salt/Mix); SK-65 Compound (Salt/Mix); Synalgos (Salt/Mix); Synalgos-DC (Salt/Mix); Vanquish (Salt/Mix); component of A.S.A. Compound (Salt/Mix); component of Ansemco 2 (Salt/Mix); component of Dilone (Salt/Mix); component of Midol (Salt/Mix); component of P-A-C Compound (Salt/Mix); component of Percodan (Salt/Mix)
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Phase change data
Go To: Top, 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
AC - William E. Acree, Jr., James S. Chickos
DH - Eugene S. Domalski and Elizabeth D. Hearing
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Tfus | 509.3 | K | N/A | Bruns, Reichelt, et al., 1984 | Crystal phase 1 phase; Uncertainty assigned by TRC = 0.1 K; TRC |
| Tfus | 508. | K | N/A | Grady, Hays, et al., 1973 | Uncertainty assigned by TRC = 1. K; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Ttriple | 508.3 | K | N/A | Weinstein, Leffler, et al., 1984 | Crystal phase 1 phase; Uncertainty assigned by TRC = 1.5 K; DSC; TRC |
Enthalpy of vaporization
| ΔvapH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 64.9 ± 2.4 | 634. to 743. | DSC | Boller and Wiedemann, 1998 | AC |
Enthalpy of sublimation
| ΔsubH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 103.6 | 423. | UV | Ebeling and Franck, 2010 | Based on data from 373. to 473. K.; AC |
| 112.6 ± 2.4 | 315. to 364. | ME | Boller and Wiedemann, 1998 | AC |
Enthalpy of fusion
| ΔfusH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 24.8 | 507.7 | DSC | Guo, Sadiq, et al., 2010 | AC |
| 19.86 | 509.5 | DSC | Dong, Li, et al., 2007 | AC |
| 21.9 | 510.2 | DSC | Pinto and Diogo, 2006 | AC |
| 19.38 | 510.2 | DSC | Klous, Bronner, et al., 2005 | AC |
| 18.3 | 510. | N/A | Domalski and Hearing, 1990 | See also Ohm and Lippold, 1985.; AC |
| 20.95 | 508.3 | DSC | Weinstein, Leffler, et al., 1984, 2 | AC |
Enthalpy of phase transition
| ΔHtrs (kJ/mol) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
|---|---|---|---|---|---|
| 0.940 | 426. | crystaline, II | crystaline, I | Cesaro and Starec, 1980 | to form.; DH |
| 5.600 | 512. | crystaline, I | liquid | Cesaro and Starec, 1980 | to liquid.; DH |
| 0.9632 | 414. | crystaline, II | crystaline, I | Bothe and Cammenga, 1979 | Low temperature to a high temperature transition.; DH |
| 5.160 | 509.3 | crystaline, I | liquid | Bothe and Cammenga, 1979 | DH |
Entropy of phase transition
| ΔStrs (J/mol*K) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
|---|---|---|---|---|---|
| 2.2 | 426. | crystaline, II | crystaline, I | Cesaro and Starec, 1980 | to; DH |
| 10.9 | 512. | crystaline, I | liquid | Cesaro and Starec, 1980 | DH |
| 6.83 | 414. | crystaline, II | crystaline, I | Bothe and Cammenga, 1979 | Low; DH |
| 10.1 | 509.3 | crystaline, I | liquid | Bothe and Cammenga, 1979 | DH |
References
Go To: Top, Phase change data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Bruns, Reichelt, et al., 1984
Bruns, S.; Reichelt, J.; Cammenga, H.K.,
Thermochemical investigation of theophylline, theophylline hydrate and their aqueous solutions,
Thermochim. Acta, 1984, 72, 31. [all data]
Grady, Hays, et al., 1973
Grady, L.T.; Hays, S.E.; King, R.H.; Klein, H.R.; Mader, W.J.; Wyatt, D.K.; Zimmere, R.O.,
Drug purity profiles,
J. Pharm. Sci., 1973, 62, 459. [all data]
Weinstein, Leffler, et al., 1984
Weinstein, D.I.; Leffler, A.J.; Currie, J.A.,
Phase Transitions in Bicyclic Compounds,
Mol. Cryst. Liq. Cryst., 1984, 104, 95. [all data]
Boller and Wiedemann, 1998
Boller, A.; Wiedemann, H.G.,
Journal of Thermal Analysis and Calorimetry, 1998, 53, 2, 431-439, https://doi.org/10.1023/A:1010133106907
. [all data]
Ebeling and Franck, 2010
Ebeling, H.; Franck, E.U.,
Spectroscopic Determination of Caffeine Solubility in Supercritical Carbon Dioxide,
Berichte der Bunsengesellschaft für physikalische Chemie, 2010, 88, 9, 862-865, https://doi.org/10.1002/bbpc.19840880918
. [all data]
Guo, Sadiq, et al., 2010
Guo, Kun; Sadiq, Ghazala; Seaton, Colin; Davey, Roger; Yin, Qiuxiang,
Co-Crystallization in the Caffeine/Maleic Acid System: Lessons from Phase Equilibria,
Crystal Growth & Design, 2010, 10, 1, 268-273, https://doi.org/10.1021/cg900885n
. [all data]
Dong, Li, et al., 2007
Dong, Jia-Xin; Li, Qiang; Tan, Zhi-Cheng; Zhang, Zhi-Heng; Liu, Yi,
The standard molar enthalpy of formation, molar heat capacities, and thermal stability of anhydrous caffeine,
The Journal of Chemical Thermodynamics, 2007, 39, 1, 108-114, https://doi.org/10.1016/j.jct.2006.05.009
. [all data]
Pinto and Diogo, 2006
Pinto, Susana S.; Diogo, Hermínio P.,
Thermochemical study of two anhydrous polymorphs of caffeine,
The Journal of Chemical Thermodynamics, 2006, 38, 12, 1515-1522, https://doi.org/10.1016/j.jct.2006.04.008
. [all data]
Klous, Bronner, et al., 2005
Klous, Marjolein G.; Bronner, Gaby M.; Nuijen, Bastiaan; Ree, Jan M. van; Beijnen, Jos H.,
Pharmaceutical heroin for inhalation: Thermal analysis and recovery experiments after volatilisation,
Journal of Pharmaceutical and Biomedical Analysis, 2005, 39, 5, 944-950, https://doi.org/10.1016/j.jpba.2005.06.011
. [all data]
Domalski and Hearing, 1990
Domalski, Eugene S.; Hearing, Elizabeth D.,
Heat Capacities and Entropies of Organic Compounds in the Condensed Phase Volume II,
J. Phys. Chem. Ref. Data, 1990, 19, 4, 881, https://doi.org/10.1063/1.555876
. [all data]
Ohm and Lippold, 1985
Ohm, A.; Lippold, B.C.,
Surface tension of solid drugs and its correlation with solubility,
Int. J. Pharm. Tech. Prod. Mfg., 1985, 6, 4, 1. [all data]
Weinstein, Leffler, et al., 1984, 2
Weinstein, D.I.; Leffler, A.J.; Currie, J.A.,
Phase Transitions In Bicyclic Compounds,
Molecular Crystals and Liquid Crystals, 1984, 104, 1-2, 95-109, https://doi.org/10.1080/00268948408070401
. [all data]
Cesaro and Starec, 1980
Cesaro, A.; Starec, G.,
Thermodynamic properties of caffeine crystal forms,
J. Phys. Chem., 1980, 84, 1345-1346. [all data]
Bothe and Cammenga, 1979
Bothe, H.; Cammenga, H.K.,
Phase transitions and thermodynamic properties of anhydrous caffeine,
J. Therm. Anal., 1979, 16, 267-275. [all data]
Notes
Go To: Top, Phase change data, References
- Symbols used in this document:
Tfus Fusion (melting) point Ttriple Triple point temperature ΔHtrs Enthalpy of phase transition ΔStrs Entropy of phase transition ΔfusH Enthalpy of fusion ΔsubH Enthalpy of sublimation ΔvapH Enthalpy of vaporization - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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