4-Aminobenzoic acid
- Formula: C7H7NO2
- Molecular weight: 137.1360
- IUPAC Standard InChI: InChI=1S/C7H7NO2/c8-6-3-1-5(2-4-6)7(9)10/h1-4H,8H2,(H,9,10)
- IUPAC Standard InChIKey: ALYNCZNDIQEVRV-UHFFFAOYSA-N
- CAS Registry Number: 150-13-0
- 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: p-Aminobenzoic acid; Aminobenzoic Acid; Benzoic acid, 4-amino-; Benzoic acid, p-amino-; p-Carboxyaniline; p-Carboxyphenylamine; Amben; anti-Chromotrichia Factor; Anticanitic vitamin; Chromotrichia factor; Hachemina; Pabacyd; Pabafilm; Pabamine; Paraminol; Paranate; PAB; PABA; Trichochromogenic Factor; Vitamin BX; Vitamin H'; 4-Carboxyaniline; γ-Aminobenzoic acid; Aminobenzoic acid, para; Bacterial vitamin H1; Pabanol; Super Shade by Coppertone; 1-Amino-4-carboxybenzene; Kyselina p-aminobenzoova; Sunbrella; RVPaba Lipstick; para-Aminobenzoic acid; Romavit; Aniline-4-carboxylic acid; Anticantic vitamin; Pabagel; component of Presun; 8014-65-1; component of Presun (Salt/Mix)
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, 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: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | -293.9 ± 4.1 | kJ/mol | Ccr | Nabavian, Sabbah, et al., 1977 | Author was aware that data differs from previously reported values |
Condensed phase 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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°solid | -410.0 ± 1.7 | kJ/mol | Ccr | Nabavian, Sabbah, et al., 1977 | Author was aware that data differs from previously reported values; ALS |
| ΔfH°solid | -413. ± 0.4 | kJ/mol | Ccb | Lebedeva, Gutner, et al., 1971 | Hfusion=5.0±0.1, see Lebedeva, Rjadnenko, et al., 1969; ALS |
| ΔfH°solid | -328.3 | kJ/mol | Ccb | Pushkareva and Kokoshko, 1946 | Author's hf298_condensed=-81.5 kcal/mol, used C as diamond; ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°solid | -3345.0 ± 1.5 | kJ/mol | Ccr | Nabavian, Sabbah, et al., 1977 | Author was aware that data differs from previously reported values; ALS |
| ΔcH°solid | -3342. ± 0.4 | kJ/mol | Ccb | Lebedeva, Gutner, et al., 1971 | Hfusion=5.0±0.1, see Lebedeva, Rjadnenko, et al., 1969; ALS |
| ΔcH°solid | -3427. | kJ/mol | Ccb | Pushkareva and Kokoshko, 1946 | Author's hf298_condensed=-81.5 kcal/mol, used C as diamond; ALS |
Constant pressure heat capacity of solid
| Cp,solid (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 187.4 | 323. | Satoh and Sogabe, 1941 | T = 0 to 100 C. Mean value.; DH |
| 177.8 | 298. | Andrews, Lynn, et al., 1926 | T = 22 to 190 C.; DH |
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
C7H6NO2- + =
By formula: C7H6NO2- + H+ = C7H7NO2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1437. ± 8.8 | kJ/mol | G+TS | Kebarle and McMahon, 1977 | gas phase |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1407. ± 8.4 | kJ/mol | IMRE | Kebarle and McMahon, 1977 | gas phase |
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
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
View reactions leading to C7H7NO2+ (ion structure unspecified)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Proton affinity (review) | 864.7 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
| Quantity | Value | Units | Method | Reference | Comment |
| Gas basicity | 832.3 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 8.3 | EI | Tobita, Tajima, et al., 1984 | LBLHLM |
| 7.8 | PE | Meeks, Wahlborg, et al., 1981 | LLK |
| 8.4 ± 0.2 | EI | Benoit, 1973 | LLK |
| 8.4 | PE | Meeks, Wahlborg, et al., 1981 | Vertical value; LLK |
Appearance energy determinations
| Ion | AE (eV) | Other Products | Method | Reference | Comment |
|---|---|---|---|---|---|
| C6H6N+ | 14.8 ± 0.2 | CO+OH | EI | Benoit, 1973 | LLK |
| C7H6NO+ | 12.1 ± 0.2 | OH | EI | Benoit, 1973 | LLK |
De-protonation reactions
C7H6NO2- + =
By formula: C7H6NO2- + H+ = C7H7NO2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1437. ± 8.8 | kJ/mol | G+TS | Kebarle and McMahon, 1977 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1407. ± 8.4 | kJ/mol | IMRE | Kebarle and McMahon, 1977 | gas phase; B |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Nabavian, Sabbah, et al., 1977
Nabavian, P.M.; Sabbah, R.; Chastel, R.; Laffitte, M.,
Thermodynamique de composes azotes. II. Etude thermochimique des acides aminobenzoiques, de la pyrimidine, de l'uracile et de la thymine.,
J. Chim. Phys., 1977, 74, 115-126. [all data]
Lebedeva, Gutner, et al., 1971
Lebedeva, N.D.; Gutner, N.M.; Ryadnenko, V.L.,
Heats of combustion and formation of certain aromatic amino-derivatives,
Russ. J. Phys. Chem. (Engl. Transl.), 1971, 45, 561-562. [all data]
Lebedeva, Rjadnenko, et al., 1969
Lebedeva, N.D.; Rjadnenko, B.L.; Gutner, N.M.,
Heats of formation of some N-containing organic compounds,
Int. Conf. Calorim. Therm. (Warsaw, Poland), 1969, 1-8. [all data]
Pushkareva and Kokoshko, 1946
Pushkareva, Z.V.; Kokoshko, Z.U.,
On the question of the relation between the structure and bacteriostatic activity of sulphanilamide compounds. I. The resonance energy of some sulphanilamide compounds,
Zh. Obshch. Kim., 1946, 16, 1269-1278. [all data]
Satoh and Sogabe, 1941
Satoh, S.; Sogabe, T.,
The heat capacities of some organic compounds containing nitrogen and the atomic heat of nitrogen. (2), Sci.,
Pap. Inst. Phys. Chem. Res. (Tokyo), 1941, 38, 231-237. [all data]
Andrews, Lynn, et al., 1926
Andrews, D.H.; Lynn, G.; Johnston, J.,
The heat capacities and heat of crystallization of some isomeric aromatic compounds,
J. Am. Chem. Soc., 1926, 48, 1274-1287. [all data]
Kebarle and McMahon, 1977
Kebarle, P.; McMahon, T.B.,
Intrinsic Acidities of Substituted Phenols and Benzoic Acids Determined by Gas Phase Proton Transfer Equilibria,
J. Am. Chem. Soc., 1977, 99, 7, 2222, https://doi.org/10.1021/ja00449a032
. [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]
Tobita, Tajima, et al., 1984
Tobita, S.; Tajima, S.; Tsuchiya, T.,
The substituent effect on the single and double hydrogen atom transfer reactions in para-substituted benzoic acid isobutyl esters,
Org. Mass Spectrom., 1984, 19, 326. [all data]
Meeks, Wahlborg, et al., 1981
Meeks, J.; Wahlborg, A.; McGlynn, S.P.,
Photoelectron spectroscopy of carbonyls: Benzoic acid and its derivatives,
J. Electron Spectrosc. Relat. Phenom., 1981, 22, 43. [all data]
Benoit, 1973
Benoit, F.,
Substituent effects in mass spectrometry. III. Substituent effects in the dissociation of the molecular ions of para and meta subtituted benzoic acids,
Org. Mass Spectrom., 1973, 7, 295. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy Cp,solid Constant pressure heat capacity of solid ΔcH°solid Enthalpy of combustion of solid at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°solid Enthalpy of formation of solid at standard conditions 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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