3,4-Dihydroxybenzoic acid

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  • Identifiers

    CAS number
    99-50-3

    Molecular formula
    C7H6O4

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

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 66.16%
    Phenolic 63.24%
    Balsamic 38.36%
    Burnt 37.25%
    Vanilla 31.49%
    Medicinal 26.98%
    Smoky 25.71%
    Bitter 22.61%
    Milky 22.43%
    Creamy 21.55%

     

    Flavor
    Phenolic 60.31%
    Mild 48.14%
    Odorless 47.31%
    Nutty 39.61%
    Faint 32.85%
    Balsamic 29.06%
    Sour 28.58%
    Sweet 27.3%
    Bitter 26.32%
    Very mild 25.43%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    1.1

    pKa est.
    7.97 (neutral)

    Molecular weight
    154.12 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    369°C

    Melting point expt.

    • 221 dec °C
    • 221 °C

    Flash point

    • 187.98 ˚C est.

    Solubility expt.

    • 18200 mg/L (at 14 °C)
    • 18.2 mg/mL at 14 °C
    • Soluble
    • Soluble (in ethanol)

  • Synonyms

    • 3,4-DIHYDROXYBENZOIC ACID
    • protocatechuic acid
    • 99-50-3
    • Protocatehuic acid
    • 4-Carboxy-1,2-dihydroxybenzene
    • 4,5-Dihydroxybenzoic acid
    • Benzoic acid, 3,4-dihydroxy-
    • protocatechuate
    • MFCD00002509
    • CCRIS 6291
    • protocatechuicacid
    • EINECS 202-760-0
    • UNII-36R5QJ8L4B
    • NSC 16631
    • BRN 1448841
    • 36R5QJ8L4B
    • DTXSID4021212
    • CHEBI:36062
    • PROTOCATECHOIC ACID
    • NSC-16631
    • CHEMBL37537
    • MLS000737807
    • DTXCID601212
    • FEMA NO. 4430
    • PROTOCATECHUIC ACID (PCA)
    • DIHYDROXYBENZOIC ACID, 3,4-
    • 1ykp
    • 3,4-Dihydroxybenzoicacid
    • DROXIDOPA METABOLITE (PROTOCATECHOIC ACID)
    • 3, 4-Dihydroxybenzoic acid
    • 3,4-Dihydroxy Benzoic Acid
    • NSC16631
    • DB03946
    • SMR000528167
    • C00230
    • b-Resorcylate
    • beta-Resorcylate
    • ProtocatechicAcid
    • b-resorcylic acid
    • 4fht
    • Protacatechuic Acid
    • cid_72
    • Protocatechuic acid (M1)
    • bmse000328
    • 3,4-dihydroxy-benzoic acid
    • 3,4-dihydroxybenzoic acid (protocatechuic acid)
    • SCHEMBL39435
    • 3,4-Dihydroxybenzoate, VIII
    • Protocatechuic acid (Standard)
    • Pyrocatechol-4-carboxylic Acid
    • PROTOCATECHUIC ACID [MI]
    • HY-N0294R
    • HMS2270A17
    • KUC104409N
    • HY-N0294
    • Tox21_200167
    • BBL012232
    • BDBM50100861
    • s3975
    • STL163570
    • AKOS000119632
    • AC-9617
    • CCG-207950
    • CS-6092
    • FD22102
    • KSC-10-128
    • CAS-99-50-3
    • NCGC00246757-01
    • NCGC00246757-02
    • NCGC00257721-01
    • AS-10808
    • SY014104
    • DB-021903
    • NS00014667
    • 3,4-Dihydroxybenzoic acid, >=97.0% (T)
    • EN300-21544
    • 3,4-Dihydroxybenzoic acid, analytical standard
    • F11285
    • AE-562/40524392
    • Q418599
    • 976C8CCE-B25D-4E0A-9A6F-3CEEA7A6964F
    • Z104501142
    • 3,4-Dihydroxybenzoic acid, Vetec(TM) reagent grade, 97%
    • PROTOCATECHOIC ACID (CONSTITUENT OF MARITIME PINE)
    • Protocatechuic acid, primary pharmaceutical reference standard
    • PROTOCATECHOIC ACID (CONSTITUENT OF MARITIME PINE) [DSC]
    • Protocatechuic acid, United States Pharmacopeia (USP) Reference Standard
    • InChI=1/C7H6O4/c8-5-2-1-4(7(10)11)3-6(5)9/h1-3,8-9H,(H,10,11
    • Protocatechuic acid;1,2-Dihydroxybenzene-4-carboxylic acid;4,5-Dihydroxybenzoic acid
    • 1225528-47-1
    • 202-760-0

  • Applications

    3,4-Dihydroxybenzoic acid, CAS 99-50-3, serves as an intermediate in organic synthesis and as an antioxidant additive in cosmetic and personal care formulations; it also acts as a precursor for dyes and organic pigments and as a building block for polymerizable systems (for example, difunctional monomers for polyesters and resins); in coatings and inks, it can function as a stabilizer and functional additive to improve durability and color stability; it is also evaluated as a precursor for certain pharmaceutical and industrial chemicals. Use is subject to local regulations and formulation limits.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 102.0
    methanol 179.47
    isopropanol 50.59
    water 7.54
    ethyl acetate 13.04
    n-propanol 47.75
    acetone 61.54
    n-butanol 32.29
    acetonitrile 27.37
    DMF 158.73
    toluene 3.62
    isobutanol 19.95
    1,4-dioxane 52.38
    methyl acetate 17.89
    THF 99.68
    2-butanone 32.64
    n-pentanol 19.6
    sec-butanol 28.36
    n-hexane 0.98
    ethylene glycol 62.17
    NMP 97.13
    cyclohexane 1.57
    DMSO 182.84
    n-butyl acetate 6.47
    n-octanol 32.0
    chloroform 0.79
    n-propyl acetate 4.24
    acetic acid 24.09
    dichloromethane 2.93
    cyclohexanone 12.45
    propylene glycol 32.81
    isopropyl acetate 7.22
    DMAc 149.03
    2-ethoxyethanol 72.84
    isopentanol 21.2
    n-heptane 4.08
    ethyl formate 10.7
    1,2-dichloroethane 5.53
    n-hexanol 15.71
    2-methoxyethanol 134.57
    isobutyl acetate 1.22
    tetrachloromethane 0.45
    n-pentyl acetate 12.08
    transcutol 106.14
    n-heptanol 28.11
    ethylbenzene 2.75
    MIBK 8.37
    2-propoxyethanol 45.94
    tert-butanol 51.04
    MTBE 23.43
    2-butoxyethanol 52.96
    propionic acid 13.62
    o-xylene 4.96
    formic acid 58.94
    diethyl ether 33.5
    m-xylene 3.75
    p-xylene 2.4
    chlorobenzene 1.14
    dimethyl carbonate 12.4
    n-octane 2.56
    formamide 131.27
    cyclopentanone 28.74
    2-pentanone 19.38
    anisole 10.96
    cyclopentyl methyl ether 21.52
    gamma-butyrolactone 31.41
    1-methoxy-2-propanol 73.8
    pyridine 21.86
    3-pentanone 13.57
    furfural 22.97
    n-dodecane 2.26
    diethylene glycol 54.05
    diisopropyl ether 6.84
    tert-amyl alcohol 33.0
    acetylacetone 16.1
    n-hexadecane 2.4
    acetophenone 8.7
    methyl propionate 16.73
    isopentyl acetate 5.21
    trichloroethylene 3.51
    n-nonanol 30.12
    cyclohexanol 11.95
    benzyl alcohol 11.95
    2-ethylhexanol 8.32
    isooctanol 17.75
    dipropyl ether 15.29
    1,2-dichlorobenzene 1.33
    ethyl lactate 6.68
    propylene carbonate 7.86
    n-methylformamide 72.53
    2-pentanol 18.46
    n-pentane 2.02
    1-propoxy-2-propanol 26.98
    1-methoxy-2-propyl acetate 14.06
    2-(2-methoxypropoxy) propanol 39.1
    mesitylene 3.06
    ε-caprolactone 13.77
    p-cymene 4.62
    epichlorohydrin 36.23
    1,1,1-trichloroethane 1.05
    2-aminoethanol 74.08
    morpholine-4-carbaldehyde 73.53
    sulfolane 39.26
    2,2,4-trimethylpentane 0.97
    2-methyltetrahydrofuran 39.39
    n-hexyl acetate 17.79
    isooctane 0.78
    2-(2-butoxyethoxy)ethanol 66.86
    sec-butyl acetate 2.78
    tert-butyl acetate 9.74
    decalin 0.83
    glycerin 52.53
    diglyme 81.21
    acrylic acid 14.2
    isopropyl myristate 8.8
    n-butyric acid 11.25
    acetyl acetate 4.77
    di(2-ethylhexyl) phthalate 8.59
    ethyl propionate 5.55
    nitromethane 49.86
    1,2-diethoxyethane 25.45
    benzonitrile 4.5
    trioctyl phosphate 8.43
    1-bromopropane 3.55
    gamma-valerolactone 36.79
    n-decanol 23.8
    triethyl phosphate 4.18
    4-methyl-2-pentanol 9.55
    propionitrile 12.52
    vinylene carbonate 5.57
    1,1,2-trichlorotrifluoroethane 21.18
    DMS 7.6
    cumene 2.33
    2-octanol 16.94
    2-hexanone 6.98
    octyl acetate 15.25
    limonene 6.33
    1,2-dimethoxyethane 55.77
    ethyl orthosilicate 4.62
    tributyl phosphate 5.46
    diacetone alcohol 24.32
    N,N-dimethylaniline 12.1
    acrylonitrile 17.01
    aniline 9.2
    1,3-propanediol 62.2
    bromobenzene 0.77
    dibromomethane 1.58
    1,1,2,2-tetrachloroethane 3.44
    2-methyl-cyclohexyl acetate 4.54
    tetrabutyl urea 14.09
    diisobutyl methanol 7.18
    2-phenylethanol 11.64
    styrene 2.53
    dioctyl adipate 11.88
    dimethyl sulfate 18.76
    ethyl butyrate 5.91
    methyl lactate 18.18
    butyl lactate 10.48
    diethyl carbonate 3.51
    propanediol butyl ether 41.18
    triethyl orthoformate 5.59
    p-tert-butyltoluene 4.85
    methyl 4-tert-butylbenzoate 23.4
    morpholine 66.39
    tert-butylamine 23.4
    n-dodecanol 17.25
    dimethoxymethane 90.94
    ethylene carbonate 4.45
    cyrene 28.71
    2-ethoxyethyl acetate 21.08
    2-ethylhexyl acetate 3.84
    1,2,4-trichlorobenzene 2.05
    4-methylpyridine 12.56
    dibutyl ether 13.17
    2,6-dimethyl-4-heptanol 7.18
    DEF 34.79
    dimethyl isosorbide 39.27
    tetrachloroethylene 3.16
    eugenol 23.56
    triacetin 14.02
    span 80 28.04
    1,4-butanediol 28.93
    1,1-dichloroethane 1.93
    2-methyl-1-pentanol 12.23
    methyl formate 36.35
    2-methyl-1-butanol 18.75
    n-decane 3.65
    butyronitrile 10.42
    3,7-dimethyl-1-octanol 14.6
    1-chlorooctane 7.93
    1-chlorotetradecane 3.79
    n-nonane 3.24
    undecane 2.85
    tert-butylcyclohexane 0.7
    cyclooctane 1.33
    cyclopentanol 20.48
    tetrahydropyran 24.84
    tert-amyl methyl ether 19.26
    2,5,8-trioxanonane 72.71
    1-hexene 2.92
    2-isopropoxyethanol 33.04
    2,2,2-trifluoroethanol 12.9
    methyl butyrate 5.78

    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