4-Aminobenzoic acid
Athanor · official
C7H7NO2 · 137.14 g/mol
Also called PABA, vitamin B10, para-aminobenzoic acid, sunscreen
WarningCauses skin irritation · May cause an allergic skin reaction · Causes serious eye irritation · May cause respiratory irritation · Harmful to aquatic life with long lasting effectsNames and identifiers
- IUPAC name
- 4-aminobenzoic acid
- Synonyms
- PABA, vitamin B10, para-aminobenzoic acid
+ 37 more
sunscreen, p-aminobenzoic acid, Vitamin BX, p-Carboxyaniline, Sunbrella, 4-Carboxyaniline, Paraminol, Pabacyd, Amben, Benzoic acid, 4-amino-, p-Carboxyphenylamine, Pabafilm, Pabamine, Paranate, Romavit, Vitamin H', Bacterial vitamin H1, 1-Amino-4-carboxybenzene, Anticanitic vitamin, Chromotrichia factor, RVPaba Lipstick, Trichochromogenic factor, Papacidum, Rvpaba, Anti-chromotrichia factor, Benzoic acid, p-amino-, Super Shade by Coppertone, Acidum paraminobenzoicum, ABEE, gamma-Aminobenzoic acid, Antichromotrichia factor, DTXSID6024466, TL2TJE8QTX, CHEBI:30753, Aminobenzoic acid (USP), Aminobenzoic acid [USP], DTXCID404466
- Molecular formula
- C7H7NO2
- Empirical formula
- C7H7NO2
- Molecular weight
- 137.14 g/mol
- Exact mass
- 137.04768
- CAS number
- 150-13-0
- PubChem CID
- 978
- Canonical SMILES
- C1=CC(=CC=C1C(=O)O)N
- Isomeric SMILES
- C1=CC(=CC=C1C(=O)O)N
- InChI
- InChI=1S/C7H7NO2/c8-6-3-1-5(2-4-6)7(9)10/h1-4H,8H2,(H,9,10)
- InChIKey
- ALYNCZNDIQEVRV-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
- Appearance
- Yellowish to red crystals or prisms[2]
3 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – P-aminobenzoic acid appears as colorless crystals that discolor on exposure to light and air. (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. –shown Yellowish to red crystals or prisms [2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. V2: 152 – White or slightly yellow crystals or crystalline powder [2] Hazardous Substances Data Bank (HSDB)cites McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2003. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2003 (Plus Supplements)., p. 3476 - Odor
- Odorless[2]
- Melting point
- 188 °C[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source 188 to 189 °C 370 to 372 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. 188 °Cshown 188 °C [3] PAC Chemical Database, U.S. Department of Energy - Density
- 1.37 (NTP, 1992) - Denser than water[1]
- Solubility in water
- Freely soluble in alcohol[2]
4 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – In water, 5,390 mg/L at 25 °C; 6,110 mg/L at 30 °C [2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 386 –shown Freely soluble in alcohol [2] Hazardous Substances Data Bank (HSDB)cites McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2003. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2003 (Plus Supplements)., p. 3477 – Soluble in alkalis and ethane (C2H6) [2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. V2: 152 – For more Solubility (Complete) data for 4-AMINOBENZOIC ACID (8 total), please visit the HSDB record page. [2] Hazardous Substances Data Bank (HSDB) - log P
- log Kow = 0.83[2]
- pKa
- pKa1 = 2.38 at 25 °C[2]
2 values
Only one source reports it.
Value As written Source –shown pKa1 = 2.38 at 25 °C [2] Hazardous Substances Data Bank (HSDB)cites Kortum G et al; Dissociation Constants of Organic Acids in Aqueous Solution. International Union of Pure and Applied Chemistry. London: Butterworth (1961) – pKa2 = 4.85 at 25 °C [2] Hazardous Substances Data Bank (HSDB)cites Serjeant EP, Dempsey B; Ionization constants of organic acids in aqueous solution. IUPAC Chem Data Ser No.23. New York, NY: Pergamon pp. 321 (1979) - Vapor pressure
- 4.5 × 10⁻⁶ mmHg at 25 °C (extrapolated from measurements at higher temperatures)[2]
Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.
Calculated
- Heavy atoms
- 10
- Rings
- 1
- Aromatic rings
- 1
- Fraction sp³ carbons (Fsp3)
- 0
- H-bond donors
- 2
- H-bond acceptors
- 2 computed here · PubChem 3
- Rotatable bonds
- 1
- TPSA (Ų)
- 63.3
- Formal charge
- 0
- XLogP3
- 0.8 PubChem
- Complexity
- 128 PubChem
- Stereocenters
- None
- Double-bond geometry
- None specified
- Point group
- C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C61.31%
- H5.15%
- N10.21%
- O23.33%
Isotope pattern
Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.
Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.
Predicted
- log P
- 0.97 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -1.68 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 1.44 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 137.14
- log P ≤ 5 (Crippen): 0.97
- H-bond donors ≤ 5: 2
- H-bond acceptors ≤ 10: 2
Passes all four rules.
¹³C NMR shifts, predicted
Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.
Safety
Warning
Most widely reported: 242 company reports to ECHA. Source [4].
- Harmful or irritant
- H315Causes skin irritation (32.2% of reports)
- H317May cause an allergic skin reaction (27.7% of reports)
- H319Causes serious eye irritation (33.1% of reports)
- H335May cause respiratory irritation (32.2% of reports)
- H412Harmful to aquatic life with long lasting effects (44.6% of reports)
Precautionary statements: P261, P264, P264+P265, P271, P272, P273, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P333+P317, P337+P317, P362+P364, P403+P233, P405, P501
View all classifications (2)
- [4] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 21.9% (53 of 242) of reports.
- [4] European Chemicals Agency (ECHA) · 242 reports · WarningH315, H317, H319, H335, H412
First aid
- Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]
Storage
- Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Recommended storage temperature: 2 - 8 °C. Air and light sensitive.[2]
Incompatibilities
- Incompatible materials: Strong oxidizing agents.[2]
Safety data sheets on the supplier’s page: LGC Standards, Biorbyt, J&H Chemical Co.,ltd.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRHazardous Substances Data Bank (HSDB) · NMRShiftDB
- 1H NMRHuman Metabolome Database (HMDB) (Varian · 600 MHz · Water) · Human Metabolome Database (HMDB) (JEOL · 400 MHz · DMSO-d6) · Human Metabolome Database (HMDB) (Bruker · D2O) · SpectraBase (BRUKER AC-300)
- 13C NMRSpectraBase
- 1H-1H NMRHuman Metabolome Database (HMDB)
- 1H-13C NMRHuman Metabolome Database (HMDB) (Bruker · 600 MHz · Water)
- GC-MSHuman Metabolome Database (HMDB) (EI-B · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive) · Human Metabolome Database (HMDB) (GC-MS) · Human Metabolome Database (HMDB) (GC-MS) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive) · Human Metabolome Database (HMDB) (GC-MS)
- MS-MSHuman Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Positive) · Human Metabolome Database (HMDB) (Positive) · Human Metabolome Database (HMDB) (Positive)
- LC-MSMassBank Europe (API3000, Applied Biosystems · LC-ESI-QQ · NEGATIVE) · MassBank Europe (API3000, Applied Biosystems · LC-ESI-QQ · NEGATIVE) · MassBank Europe (API3000, Applied Biosystems · LC-ESI-QQ · NEGATIVE) · MassBank Europe (API3000, Applied Biosystems · LC-ESI-QQ · NEGATIVE) · MassBank Europe (API3000, Applied Biosystems · LC-ESI-QQ · NEGATIVE) · MassBank Europe (API3000, Applied Biosystems · LC-ESI-QQ · POSITIVE)
- Other MSHazardous Substances Data Bank (HSDB) · MassBank Europe (HITACHI M-80A · EI-B · POSITIVE) · MassBank Europe (waters xevo g2 TOF · ESI-TOF · POSITIVE) · MassBank Europe (waters xevo g2 TOF · ESI-TOF · POSITIVE) · MassBank of North America (MoNA) (TQD, Waters · Flow-injection QqQ/MS · ESI) · MassBank of North America (MoNA) (TQD, Waters · Flow-injection QqQ/MS · ESI)
- UVHazardous Substances Data Bank (HSDB)
- UV-VISSpectraBase
- IRHazardous Substances Data Bank (HSDB)
- FTIRSpectraBase (Bio-Rad FTS · KBr0)
- ATR-IRSpectraBase (PerkinElmer SpectrumTwo · ATR-IR)
- Vapor Phase IRSpectraBase (Bruker IFS 85 · Gas-GC)
- RamanSpectraBase (FT-Raman)
Experimental spectra held by these sources; each link opens the source's own record.
Literature
Reading PubChem, OpenAlex and GSRS…
Bioactivity
Reading ChEMBL…
References
- [1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
- [2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
- [3]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
- [4]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [5]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [6]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
- [7]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [8]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
- [9]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [10]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
- ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
- ·Literature on PubChem
Data last updated 2026-10-14.