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Record Information
StatusDetected and Quantified
Creation Date2006-05-22 14:17:34 UTC
Update Date2020-02-26 21:23:46 UTC
Secondary Accession Numbers
  • HMDB02056
Metabolite Identification
Common NameMonoisobutyl phthalic acid
DescriptionMonoisobutyl phthalic acid, also known as isobutyl hydrogen phthalate or MIBP, belongs to the class of organic compounds known as benzoic acid esters. These are ester derivatives of benzoic acid. Phthalates are synthetic industrial compounds capable of disrupting the endocrine system. Fetal testicular dysgenesis syndrome, otherwise known as the ”phthalate syndrome” in rodents, is a consequence of reduced level of fetal testosterone, insulin-like growth factor-3 (IGF-3) and follicule stimulating hormone (FSH). Monoisobutyl phthalic acid is an extremely weak basic (essentially neutral) compound (based on its pKa). Monoisobutyl phthalic acid is a potentially toxic compound. Exposure to phthalates is significantly associated with the duration of pregnancy. Phthalates, when acting in a critical period of the development of genital tract, lead to disturbances in the androgen-signaling pathway. A negative correlation between levels in breast milk and free testosterone of babies was observed, while there was a positive correlation between mono-ethyl phthalate (MEP) and mono-butyl (MBP) with sex hormone bingind globuline (SHBG) and mono-metyl phthalate (MMP) and MEP and MBP with the ratio of lutenzing hormone (LH) and free testosterone.
1,2-Benzenedicarboxylic acid, mono(2-methylpropyl) esterChEBI
2-(Isobutoxycarbonyl)benzoic acidChEBI
Isobutyl hydrogen phthalateChEBI
mono-Iso-butyl phthalateChEBI
Phthalic acid, monoisobutyl esterChEBI
1,2-Benzenedicarboxylate, mono(2-methylpropyl) esterGenerator
Isobutyl hydrogen phthalic acidGenerator
mono-Iso-butyl phthalic acidGenerator
Phthalate, monoisobutyl esterGenerator
Monoisobutyl phthalateGenerator
Monoisobutyl phthalic acidChEBI
Chemical FormulaC12H14O4
Average Molecular Weight222.2372
Monoisotopic Molecular Weight222.089208936
IUPAC Name2-[(2-methylpropoxy)carbonyl]benzoic acid
Traditional NameMIBP
CAS Registry Number30833-53-5
InChI Identifier
Chemical Taxonomy
Description belongs to the class of organic compounds known as benzoic acid esters. These are ester derivatives of benzoic acid.
KingdomOrganic compounds
Super ClassBenzenoids
ClassBenzene and substituted derivatives
Sub ClassBenzoic acids and derivatives
Direct ParentBenzoic acid esters
Alternative Parents
  • Benzoate ester
  • Benzoic acid
  • Benzoyl
  • Dicarboxylic acid or derivatives
  • Carboxylic acid ester
  • Carboxylic acid
  • Carboxylic acid derivative
  • Organic oxygen compound
  • Organic oxide
  • Hydrocarbon derivative
  • Organooxygen compound
  • Aromatic homomonocyclic compound
Molecular FrameworkAromatic homomonocyclic compounds
External DescriptorsNot Available


Biological location:

Physical Properties
Experimental Properties
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility0.79 g/LALOGPS
pKa (Strongest Acidic)3.08ChemAxon
pKa (Strongest Basic)-7ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area63.6 ŲChemAxon
Rotatable Bond Count5ChemAxon
Refractivity59.08 m³·mol⁻¹ChemAxon
Polarizability22.83 ųChemAxon
Number of Rings1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-0002-4910000000-ac2484b74eb5cfd5b690Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-00di-6390000000-4ca9de5bf766a991b3dcSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QFT , negativesplash10-0089-0930000000-d249a5cd21193a8a3cd2Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QFT , positivesplash10-0002-0900000000-13d64e3eb0a1e3e235beSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0ab9-6690000000-8f32418bd6ccde0549c0Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0a4i-9720000000-286cdd7561a043eef3d0Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0a4i-9500000000-6c3aca6817c2db6bb804Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-00di-1790000000-2d20ca2ec96d84986321Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0100-2910000000-46c6c191f37b2782021aSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-00di-6900000000-0d9a0ca1ebdbc964dac0Spectrum
Biological Properties
Cellular Locations
  • Membrane (predicted from logP)
Biospecimen Locations
  • Blood
  • Saliva
  • Urine
Tissue LocationsNot Available
Normal Concentrations
BloodDetected and Quantified0.0022 (0.0-0.0044) uMAdult (>18 years old)BothNormal details
SalivaDetected and Quantified0.0805 uMAdult (>18 years old)BothNormal details
UrineDetected and Quantified0.00379 (0.00346-0.00415) umol/mmol creatinineAdult (>18 years old)Not SpecifiedNormal
    • National Health a...
UrineDetected and Quantified0.00672 (0.00600-0.00758) umol/mmol creatinineChildren (1-13 years old)Not SpecifiedNormal
    • National Health a...
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FooDB IDFDB022820
KNApSAcK IDNot Available
Chemspider ID83306
KEGG Compound IDNot Available
BioCyc IDNot Available
BiGG IDNot Available
Wikipedia LinkNot Available
METLIN IDNot Available
PubChem Compound92272
PDB IDNot Available
ChEBI ID90038
Food Biomarker OntologyNot Available
VMH IDNot Available
Synthesis ReferenceKe, Changying. Esterification synthesis of diisobutyl phthalate. Huaxue Shijie (1986), 27(10), 440-2.
Material Safety Data Sheet (MSDS)Not Available
General References
  1. Silva MJ, Reidy JA, Samandar E, Herbert AR, Needham LL, Calafat AM: Detection of phthalate metabolites in human saliva. Arch Toxicol. 2005 Nov;79(11):647-52. Epub 2005 Jul 2. [PubMed:15995852 ]
  2. Kato K, Silva MJ, Needham LL, Calafat AM: Quantifying phthalate metabolites in human meconium and semen using automated off-line solid-phase extraction coupled with on-line SPE and isotope-dilution high-performance liquid chromatography--tandem mass spectrometry. Anal Chem. 2006 Sep 15;78(18):6651-5. [PubMed:16970347 ]
  3. Silva MJ, Slakman AR, Reidy JA, Preau JL Jr, Herbert AR, Samandar E, Needham LL, Calafat AM: Analysis of human urine for fifteen phthalate metabolites using automated solid-phase extraction. J Chromatogr B Analyt Technol Biomed Life Sci. 2004 Jun 5;805(1):161-7. [PubMed:15113553 ]