4-Hydroxybenzoic acid

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  • Identifiers

    CAS number
    99-96-7

    Molecular formula
    C7H6O3

    SMILES
    C1=CC(=CC=C1C(=O)O)O

    Safety labels

    Corrosive
    Corrosive

    Irritant
    Irritant

  • Odor profile

    Phenolic 76.1%
    Nutty 48.78%
    Odorless 46.51%
    Medicinal 41.34%
    Burnt 40.47%
    Balsamic 36.64%
    Bitter 30.22%
    Aromatic 30.14%
    Vanilla 29.68%
    Smoky 29.54%

    Scent© AI

  • Properties

    XLogP3-AA
    1.6

    Molecular weight
    138.12 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Melting point expt.

    • 214.5 °C
    • 213.00 to 215.00 °C. @ 760.00 mm Hg

    Boiling point

    • 334.00 to 335.00 °C. @ 760.00 mm Hg

    Flash point est.
    174.55 ˚C

    Solubility expt.

    • Solubility (in 100 g of solution): 99% ethanol 38.75 g (67 °C); n-butanol 19.5 g (32.5 °C)
    • Soluble in about 125 parts water, freely in alcohol, slightly in chloroform; soluble in ether, acetone. Practically insoluble in carbon disulfide.
    • In water, 5000 mg/L at 25 °C
    • 5.0 mg/mL
    • slightly soluble in water; soluble in organic solvents
    • freely soluble (in ethanol)

  • Synonyms

    • 4-HYDROXYBENZOIC ACID
    • 99-96-7
    • p-Hydroxybenzoic acid
    • 4-Carboxyphenol
    • p-Salicylic acid
    • Benzoic acid, 4-hydroxy-
    • Benzoic acid, p-hydroxy-
    • p-carboxyphenol
    • para-Hydroxybenzoic acid
    • Paraben-acid
    • 4-Hydroxybenzoesaeure
    • p-Oxybenzoesaure
    • Kyselina 4-hydroxybenzoova
    • p-Oxybenzoesaure [German]
    • NSC 4961
    • parahydroxybenzoic acid
    • Acido p-idrossibenzoico
    • 4-hydroxy-benzoic acid
    • Hydroxybenzoic acid
    • HSDB 7233
    • Acido p-idrossibenzoico [Italian]
    • Kyselina 4-hydroxybenzoova [Czech]
    • EINECS 202-804-9
    • UNII-JG8Z55Y12H
    • CCRIS 8812
    • JG8Z55Y12H
    • DTXSID3026647
    • CHEBI:30763
    • HYDROXYBENZOIC ACID, PARA
    • p-hydroxy benzoic acid
    • AI3-01003
    • p-hydroxy-Benzoic acid
    • NSC-4961
    • Benzoic acid, 4-hydroxy
    • MFCD00002547
    • Hydroxybenzenecarboxylic acid
    • 4-HBA
    • CHEMBL441343
    • DTXCID806647
    • FEMA NO. 3986
    • EC 202-804-9
    • 3pcc
    • 3pch
    • 4-hydroxy-benzoate
    • 4-hydroxy benzoic acid
    • 4-Hydroxybenzoicacid
    • Benzoic acid, p-hydroxy
    • WLN: QVR DQ
    • PHB
    • CAS-99-96-7
    • NSC4961
    • SALICYLIC ACID IMPURITY A (EP IMPURITY)
    • SALICYLIC ACID IMPURITY A [EP IMPURITY]
    • DB04242
    • NCGC00166040-01
    • ACETYLSALICYLIC ACID IMPURITY A (EP IMPURITY)
    • ACETYLSALICYLIC ACID IMPURITY A [EP IMPURITY]
    • PROPYL HYDROXYBENZOATE IMPURITY A (EP IMPURITY)
    • PROPYL HYDROXYBENZOATE IMPURITY A [EP IMPURITY]
    • METHYL PARAHYDROXYBENZOATE IMPURITY A (EP IMPURITY)
    • METHYL PARAHYDROXYBENZOATE IMPURITY A [EP IMPURITY]
    • C00156
    • p-Salicylate
    • AE-848/32195059
    • p-hydroxy-Benzoate
    • 4-hydoxybenzoic acid
    • 4-hyroxybenzoic acid
    • phenol derivative, 8
    • 4-hydroxylbenzoic acid
    • 4-Hydroxy-benzoesaeure
    • 4-hydroxybenzoi c acid
    • PHLORETIN_met004
    • 4-hydroxyl benzoic acid
    • 4-Hydroxybenzoate, III
    • AVOBENZONE_met002
    • para-hydroxy benzoic acid
    • bmse000092
    • bmse000583
    • SCHEMBL4110
    • BIDD:ER0706
    • 4-Hydroxybenzenecarboxylic acid
    • p-Hydroxybenzoic Acid, Reagent
    • BDBM26194
    • HY-Y0264R
    • 4-Hydroxybenzoic acid (Standard)
    • P-HYDROXYBENZOIC ACID [MI]
    • CS-D1180
    • HY-Y0264
    • STR01287
    • Tox21_202342
    • Tox21_303301
    • AC-008
    • BBL011981
    • s3754
    • STL138745
    • 4-HYDROXYBENZOIC ACID [FHFI]
    • 4-HYDROXYBENZOIC ACID [HSDB]
    • 4-Hydroxybenzoic acid, >=99%, FG
    • AKOS000119033
    • CCG-266143
    • FH64214
    • NCGC00166040-02
    • NCGC00257058-01
    • NCGC00259891-01
    • H0207
    • NS00005418
    • 4-Hydroxybenzoic acid, ReagentPlus(R), 99%
    • EN300-21461
    • D86505
    • 4-Hydroxybenzoic acid, ReagentPlus(R), >=99%
    • 4-Hydroxybenzoic acid, puriss., >=99.0% (T)
    • Q229970
    • 46DD083D-BFD3-4CE1-B2D9-6C6D5FEFD3D9
    • 4-Hydroxybenzoic acid, Vetec(TM) reagent grade, 99%
    • 2-3-4'-TRIHYDROXY-4-METHOXYBENZOPHENONE_met005
    • F2191-0237
    • Z104498098
    • 2-3-DIHYDROXY-4-METHOXY-4'-ETHOXYBENZOPHENONE_met009
    • 4-Hydroxybenzoic acid, certified reference material, TraceCERT(R)
    • 4-Hydroxybenzoic acid, Pharmaceutical Secondary Standard; Certified Reference Material
    • InChI=1/C7H6O3/c8-6-3-1-5(2-4-6)7(9)10/h1-4,8H,(H,9,10
    • 202-804-9
    • 30729-36-3

  • Applications

    4-Hydroxybenzoic acid (p-HBA, CAS 99-96-7) is widely applied as an intermediate to produce parabens (methyl/ethyl/propyl/butyl) used as preservatives in cosmetics, pharmaceuticals, and foods; as a monomer/building block for aromatic polyesters and liquid-crystal polymers with high thermal and mechanical performance in electronic connectors, automotive parts, and high-performance fibers and films; as a precursor to dyes, agrochemical intermediates, and many functional derivatives (p-hydroxybenzoate esters, ethers, and amides) for coatings, inks, and polymer modification; and in research as a phenolic standard and analytical reference (HPLC/LC-MS) as well as a versatile organic building block for ester/amide formation and coupling routes to bioactive molecules.

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 38.34
    methanol 56.12
    isopropanol 25.23
    water 1.54
    ethyl acetate 13.48
    n-propanol 22.45
    acetone 37.2
    n-butanol 19.39
    acetonitrile 11.75
    DMF 119.58
    toluene 0.72
    isobutanol 12.15
    1,4-dioxane 152.76
    methyl acetate 15.37
    THF 133.48
    2-butanone 18.82
    n-pentanol 15.75
    sec-butanol 14.62
    n-hexane 0.28
    ethylene glycol 29.41
    NMP 152.03
    cyclohexane 0.24
    DMSO 112.2
    n-butyl acetate 11.63
    n-octanol 76.69
    chloroform 0.38
    n-propyl acetate 7.6
    acetic acid 43.58
    dichloromethane 1.59
    cyclohexanone 20.13
    propylene glycol 28.07
    isopropyl acetate 10.36
    DMAc 97.46
    2-ethoxyethanol 65.8
    isopentanol 16.42
    n-heptane 1.15
    ethyl formate 14.35
    1,2-dichloroethane 3.06
    n-hexanol 15.03
    2-methoxyethanol 108.66
    isobutyl acetate 3.12
    tetrachloromethane 0.14
    n-pentyl acetate 27.82
    transcutol 325.98
    n-heptanol 35.55
    ethylbenzene 0.92
    MIBK 10.27
    2-propoxyethanol 59.99
    tert-butanol 29.91
    MTBE 13.91
    2-butoxyethanol 74.2
    propionic acid 21.85
    o-xylene 1.47
    formic acid 49.73
    diethyl ether 17.72
    m-xylene 1.24
    p-xylene 1.12
    chlorobenzene 1.04
    dimethyl carbonate 12.84
    n-octane 0.96
    formamide 79.14
    cyclopentanone 45.63
    2-pentanone 15.38
    anisole 8.33
    cyclopentyl methyl ether 21.35
    gamma-butyrolactone 74.74
    1-methoxy-2-propanol 74.58
    pyridine 13.99
    3-pentanone 9.15
    furfural 51.39
    n-dodecane 1.78
    diethylene glycol 62.88
    diisopropyl ether 4.41
    tert-amyl alcohol 18.75
    acetylacetone 26.74
    n-hexadecane 1.98
    acetophenone 9.59
    methyl propionate 14.71
    isopentyl acetate 10.93
    trichloroethylene 2.82
    n-nonanol 64.82
    cyclohexanol 9.95
    benzyl alcohol 9.29
    2-ethylhexanol 10.05
    isooctanol 25.26
    dipropyl ether 13.03
    1,2-dichlorobenzene 1.57
    ethyl lactate 11.53
    propylene carbonate 24.78
    n-methylformamide 53.94
    2-pentanol 11.67
    n-pentane 0.38
    1-propoxy-2-propanol 42.88
    1-methoxy-2-propyl acetate 26.09
    2-(2-methoxypropoxy) propanol 77.74
    mesitylene 1.35
    ε-caprolactone 31.78
    p-cymene 2.79
    epichlorohydrin 57.75
    1,1,1-trichloroethane 0.69
    2-aminoethanol 41.76
    morpholine-4-carbaldehyde 149.44
    sulfolane 92.03
    2,2,4-trimethylpentane 0.42
    2-methyltetrahydrofuran 46.83
    n-hexyl acetate 57.34
    isooctane 0.44
    2-(2-butoxyethoxy)ethanol 140.34
    sec-butyl acetate 4.97
    tert-butyl acetate 15.12
    decalin 0.4
    glycerin 59.5
    diglyme 165.58
    acrylic acid 24.6
    isopropyl myristate 21.96
    n-butyric acid 21.62
    acetyl acetate 8.94
    di(2-ethylhexyl) phthalate 20.44
    ethyl propionate 7.66
    nitromethane 78.34
    1,2-diethoxyethane 51.47
    benzonitrile 5.56
    trioctyl phosphate 20.26
    1-bromopropane 1.1
    gamma-valerolactone 96.17
    n-decanol 44.59
    triethyl phosphate 7.62
    4-methyl-2-pentanol 7.98
    propionitrile 6.78
    vinylene carbonate 16.2
    1,1,2-trichlorotrifluoroethane 36.26
    DMS 18.87
    cumene 1.24
    2-octanol 27.26
    2-hexanone 8.79
    octyl acetate 35.1
    limonene 4.19
    1,2-dimethoxyethane 71.27
    ethyl orthosilicate 7.49
    tributyl phosphate 15.4
    diacetone alcohol 34.02
    N,N-dimethylaniline 8.23
    acrylonitrile 10.78
    aniline 4.53
    1,3-propanediol 50.69
    bromobenzene 0.58
    dibromomethane 0.56
    1,1,2,2-tetrachloroethane 2.72
    2-methyl-cyclohexyl acetate 11.23
    tetrabutyl urea 29.28
    diisobutyl methanol 8.47
    2-phenylethanol 12.67
    styrene 0.94
    dioctyl adipate 31.54
    dimethyl sulfate 26.18
    ethyl butyrate 10.38
    methyl lactate 23.12
    butyl lactate 26.72
    diethyl carbonate 6.65
    propanediol butyl ether 96.24
    triethyl orthoformate 10.27
    p-tert-butyltoluene 3.17
    methyl 4-tert-butylbenzoate 42.15
    morpholine 123.77
    tert-butylamine 10.45
    n-dodecanol 29.21
    dimethoxymethane 76.66
    ethylene carbonate 13.86
    cyrene 55.02
    2-ethoxyethyl acetate 47.27
    2-ethylhexyl acetate 7.89
    1,2,4-trichlorobenzene 2.76
    4-methylpyridine 8.77
    dibutyl ether 27.62
    2,6-dimethyl-4-heptanol 8.47
    DEF 33.24
    dimethyl isosorbide 90.22
    tetrachloroethylene 1.81
    eugenol 42.46
    triacetin 47.77
    span 80 69.4
    1,4-butanediol 22.21
    1,1-dichloroethane 0.87
    2-methyl-1-pentanol 11.59
    methyl formate 36.56
    2-methyl-1-butanol 12.19
    n-decane 2.81
    butyronitrile 7.8
    3,7-dimethyl-1-octanol 30.01
    1-chlorooctane 11.8
    1-chlorotetradecane 5.02
    n-nonane 2.14
    undecane 2.26
    tert-butylcyclohexane 0.43
    cyclooctane 0.22
    cyclopentanol 20.83
    tetrahydropyran 31.83
    tert-amyl methyl ether 11.33
    2,5,8-trioxanonane 135.87
    1-hexene 1.05
    2-isopropoxyethanol 35.83
    2,2,2-trifluoroethanol 19.03
    methyl butyrate 9.05

    Scent© AI

1 4

IFRA standard 51

Recommendation
No restriction
Maximum acceptable concentrations in the finished product (%)
Category 1
Products applied to the lips
 No restriction Category 7A
Rinse-off products applied to the hair with some hand contact
 No restriction
Category 2
Products applied to the axillae
 No restriction Category 7B
Leave-on products applied to the hair with some hand contact
 No restriction
Category 3
Products applied to the face/body using fingertips
 No restriction Category 8
Products with significant anogenital exposure
 No restriction
Category 4
Products related to fine fragrance
 No restriction Category 9
Products with body and hand exposure, primarily rinse off
 No restriction
Category 5A
Body lotion products applied to the body using the hands (palms), primarily leave on
 No restriction Category 10A
Household care products with mostly hand contact
 No restriction
Category 5B
Face moisturizer products applied to the face using the hands (palms), primarily leave on
 No restriction Category 10B
Household care products with mostly hand contact, including aerosol/spray products (with potential leave-on skin contact)
 No restriction
Category 5C
Hand cream products applied to the hands using the hands (palms), primarily leave on
 No restriction Category 11A
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate without UV exposure
 No restriction
Category 5D
Baby Creams, baby Oils and baby talc
 No restriction Category 11B
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate with potential UV exposure
 No restriction
Category 6
Products with oral and lip exposure
 No restriction Category 12
Products not intended for direct skin contact, minimal or insignificant transfer to skin
 No restriction

Botanical

Name CAS Botanical Proportion
Orris butter 8002-73-1 Iris florentina L., fam. Iridaceae 0.01%
Vanilla 2 8024-06-4 Vanilla fragrans Ames (V. planifolia Andrews), fam. Orchidaceae 1.0%