Functional Roles
Industries Served
Physical Properties
physical_description
Colorless solid; [Hawley] Sublimes without decomposition; [Merck Index] Melting point = 347 deg C; [HSDB] Faintly beige powder; [MSDSonline]
color/form
Needles from water or alcohol
boiling_point
Boiling point = 753.00 K (Based on predicted value for phthalic acid by Meissner's method with a suitable adjustment for isomerism based on similar compound relationships.)
melting_point
Triple point temperature and pressure = 619.15 K (estimated to be equal to the melting point), 2.8020X10+3 Pa
solubility
In methanol: 4.0 g/100 g at 25 u00b0C; in propanol: 1.7 g/100 g at 25 u00b0C, 2.7 g/100 g at 50 u00b0C; in glacial acetic acid: 0.23 g/100 g at 25 u00b0C
density
1.54 at 77 u00b0F (USCG, 1999) - Denser than water; will sink
vapor_pressure
VP: 0.009 Pa (0.0675 mm Hg) at 100 u00b0C
logp
log Kow = 1.66
stability/shelf_life
SUBLIMES WITHOUT DECOMP
autoignition_temperature
700 u00b0C
decomposition
When heated to decomposition it emits acrid smoke and fumes.
viscosity
0.00025186 Pa-s at 619.15K (346 u00b0C)
heat_of_vaporization
1.0921X10+8 J/kmol at the melting point of 619.15 K (346 u00b0C)
surface_tension
0.048239 N/m at 346 u00b0C
dissociation_constants
pKa1 = 3.70; pKa2 = 4.60 at 25 u00b0C
collision_cross_section
133.2 u00e2u201eu00abu00c2u00b2 [M-H]- [CCS Type: DT; Buffer gas: N2; Ionization: ESI-; Dataset: TOXCAST; Source Identifier: DTXSID3021485]
other_experimental_properties
Heat of sublimation: 106.7 kJ/mol at 25 u00b0C
Chemical Identity
| CAS Number | 121-91-5 |
| IUPAC Name | benzene-1,3-dicarboxylic acid |
| InChI Key | QQVIHTHCMHWDBS-UHFFFAOYSA-N |
| PubChem CID | 8496 |
| INCI Name | ISOPHTHALIC ACID |
Synonyms & Trade Names
Full Description
Isophthalic acid (IPA) is a white crystalline solid dicarboxylic acid with the molecular formula C8H6O4, functioning as a pH adjustment agent in industrial applications. This benzene-1,3-dicarboxylic acid is primarily utilized in coatings and construction industries where precise pH control is required. The compound has a melting point of 619.15 K and a density of 1.54 g/cm³ at 77°F, making it denser than water with limited solubility in alcohols.