Salicylic acid

Formula: C₇H₆O₃
Molecular weight: 138.1207
IUPAC Standard InChI: InChI=1S/C7H6O3/c8-6-4-2-1-3-5(6)7(9)10/h1-4,8H,(H,9,10)
IUPAC Standard InChIKey: YGSDEFSMJLZEOE-UHFFFAOYSA-N
CAS Registry Number: 69-72-7
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other names: Benzoic acid, 2-hydroxy-; o-Hydroxybenzoic acid; Phenol-2-carboxylic acid; Psoriacid-S-Stift; Retarder W; Rutranex; Salicylic acid collodion; Salonil; 2-Hydroxybenzoic acid; Acido salicilico; Keralyt; Kyselina 2-hydroxybenzoova; Kyselina salicylova; Orthohydroxybenzoic acid; Duoplant; Freezone; Ionil; Saligel; Compound W; 2-Hydroxybenzenecarboxylic acid; 2-Carboxyphenol; o-Carboxyphenol; Advanced pain relief callus removers; Advanced pain relief corn removers; Clear away wart remover; Dr. Scholl's Callus Removers; Dr. Scholl's Corn Removers; Dr. Scholl's Wart Remover Kit; Duofil Wart Remover; Ionil plus; Salicylic acid soap; Stri-Dex; Benzoic acid, o-hydroxy-; NSC 180; Trans-Ver-Sal; Domerine; Duofilm; Fostex; Pernox; Salicylic acid & Sulfur Soap; Sebucare; Sebulex; component of Fostex medicated bar and cream; component of Keralyt; Retarder SAX; component of Solarcaine first aid spray; component of Tinver; 7681-06-3; 8052-31-1; Salicyclic acid; Domerine (Salt/Mix); Duofilm (Salt/Mix); Fostex (Salt/Mix); Pernox (Salt/Mix); Salicylic acid & Sulfur Soap (Salt/Mix); Sebucare (Salt/Mix); Sebulex (Salt/Mix); component of Fostex medicated bar and cream (Salt/Mix); component of Keralyt (Salt/Mix); Retarder SAX (Salt/Mix); component of Solarcaine first aid spray (Salt/Mix); component of Tinver (Salt/Mix)
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Condensed phase thermochemistry data

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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
Δ_fH°_solid	-592.1 ± 1.3	kJ/mol	Ccr	Sabbah and Le, 1993	ALS
Δ_fH°_solid	-589.7 ± 1.1	kJ/mol	Ccb	Colomina, Jimenez, et al., 1980	ALS
Δ_fH°_solid	-585.3	kJ/mol	Ccb	Verkade, 1932	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_solid	-3025. ± 5.	kJ/mol	AVG	N/A	Average of 12 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
S°_{solid,1 bar}	172.4	J/mol*K	N/A	Rabinovich, Sheiman, et al., 1986	DH
S°_{solid,1 bar}	178.2	J/mol*K	N/A	Parks and Light, 1934	Extrapolation below 90 K, 57.32 J/mol*K.; DH

Constant pressure heat capacity of solid

C_p,solid (J/mol*K)	Temperature (K)	Reference	Comment
160.9	298.15	Rabinovich, Sheiman, et al., 1986	T = 5 to 460 K.; DH
104.2	293.	Campbell and Campbell, 1940	DH
159.4	288.6	Parks and Light, 1934	T = 96 to 289 K. Value is unsmoothed experimental datum.; DH

Reaction thermochemistry data

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Data compiled as indicated in comments:
B - John E. Bartmess
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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

C₇H₅O₃^- + = Salicylic acid

By formula: C₇H₅O₃^- + H⁺ = C₇H₆O₃

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1362. ± 9.2	kJ/mol	G+TS	Kebarle and McMahon, 1977	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1330. ± 8.4	kJ/mol	IMRE	Kebarle and McMahon, 1977	gas phase; B

+ = + Salicylic acid

By formula: C₉H₈O₄ + H₂O = C₂H₄O₂ + C₇H₆O₃

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-27.2 ± 0.3	kJ/mol	Cm	Nelander, 1964	solid phase; Heat of hydrolysis; ALS

Gas phase ion energetics data

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Data compiled by: John E. Bartmess

View reactions leading to C₇H₆O₃⁺ (ion structure unspecified)

De-protonation reactions

C₇H₅O₃^- + = Salicylic acid

By formula: C₇H₅O₃^- + H⁺ = C₇H₆O₃

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1362. ± 9.2	kJ/mol	G+TS	Kebarle and McMahon, 1977	gas phase
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1330. ± 8.4	kJ/mol	IMRE	Kebarle and McMahon, 1977	gas phase

References

Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Notes

Sabbah and Le, 1993
Sabbah, R.; Le, T.H.D., Etude thermodynamique des trois isomeres de l'acide bydroxybenzolque, Can. J. Chem., 1993, 71, 1378-1383. [all data]

Colomina, Jimenez, et al., 1980
Colomina, M.; Jimenez, P.; Roux, M.V.; Turrion, C., Thermochemical properties of o-, m- and p-hydroxybenzoic acids, J. Calorim. Anal. Therm., 1980, 11, 1-6. [all data]

Verkade, 1932
Verkade, P.-E., L'acide salicylique comme substance-etalon secondaire de calorimetrie, J. Chim. Phys., 1932, 29, 297-301. [all data]

Rabinovich, Sheiman, et al., 1986
Rabinovich, I.B.; Sheiman, M.S.; Kamelova, G.P.; Nistratov, V.P., Heat capacity and thermodynamic functions of salicylic acid, 1986, Termodinam. [all data]

Parks and Light, 1934
Parks, G.S.; Light, D.W., Thermal data on organic compounds. XIII. The heat capacities and entropies of n-tetradecane and the hydroxybenzoic acids. The relative free energies of some benzenoid position isomers, J. Am. Chem. Soc., 1934, 56, 1511-1513. [all data]

Campbell and Campbell, 1940
Campbell, A.N.; Campbell, A.J.R., The heats of solution, heats of formation, specific heats and equilibrium diagrams of certain molecular compounds. J. Am. Chem. Soc., 1940, 62, 291-297. [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]

Nelander, 1964
Nelander, L., The heats of hydrolysis of aspirin, thioaspirin, and their p-analogues, Acta Chem. Scand., 1964, 18, 973-984. [all data]

Notes

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Symbols used in this document:

C_p,solid	Constant pressure heat capacity of solid
S°_{solid,1 bar}	Entropy of solid at standard conditions (1 bar)
Δ_cH°_solid	Enthalpy of combustion of solid at standard conditions
Δ_fH°_solid	Enthalpy of formation of solid at standard conditions
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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