Hydroquinone

Overview IFRA Botanical Request a quote

  • Identifiers

    CAS number
    123-31-9

    Molecular formula
    C6H6O2

    SMILES
    C1=CC(=CC=C1O)O

    Safety labels

    Corrosive
    Corrosive

    Irritant
    Irritant

    Health Hazard
    Health

    Environmental Hazard
    Environmental

  • Odor profile

    Phenolic 88.44%
    Medicinal 62.9%
    Smoky 47.41%
    Burnt 45.19%
    Nutty 41.03%
    Sweet 39.18%
    Musty 35.4%
    Woody 31.76%
    Animal 30.42%
    Vanilla 29.86%

    Scent© AI

  • Properties

    XLogP3-AA
    0.6

    Molecular weight
    110.11 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Melting point expt.

    • 338 to 340 °F (EPA, 1998)
    • 170-171
    • 170-171 °C
    • MP: 173 °C; BP 288 °C
    • Heat of fusion at melting point = 2.71X10+7 J/kmol
    • 172.3 °C
    • 172 °C
    • 338 °F

    Boiling point

    • 545 to 549 °F at 760 mmHg (EPA, 1998)
    • 285-287
    • 285-287 °C
    • 286.00 to 288.00 °C. @ 760.00 mm Hg
    • 287 °C
    • 545 °F

    Flash point est.
    142.81 ˚C

    Flash point expt.

    • 329 °F (EPA, 1998)
    • 329 °F
    • 329 °F (CLOSED CUP)
    • 165 °C (329 °F) (Closed cup)
    • 329 °F (165 °C) (Closed cup)
    • 165 °C
    • 329 °F (Molten)

    Solubility expt.

    • 10 to 50 mg/mL at 68 °F (NTP, 1992)
    • 6.72g/L at 20 deg C
    • In water, 72,000 mg/L at 25 °C
    • In water, 6.72 g/L at 20 °C. Also water solubility = 3.85 g/L at 0 °C; 5.12 g/L at 10 °C; 5.40 g/L at 15 °C; 8.76 g/L at 30 °C; 11.5 g/L at 40 °C; 25/9 g/L at 60 °C; 46.8 g/L at 80 °C; 66.4 g/L at 100 °C
    • 7% soluble in water at 25 °C
    • Grams of hydroquinone per 100 g solvent (30 °C); ethanol 46.4; acetone 28.4; water 8.3; benzene 0.06; tetrachloromethane 0.01
    • For more Solubility (Complete) data for HYDROQUINONE (6 total), please visit the HSDB record page.
    • 72.0 mg/mL at 25 °C
    • Solubility in water, g/100ml at 15 °C: 5.9
    • 7%

  • Synonyms

    • hydroquinone
    • 123-31-9
    • Benzene-1,4-diol
    • 1,4-benzenediol
    • Quinol
    • 1,4-Dihydroxybenzene
    • p-Benzenediol
    • p-Hydroquinone
    • p-Hydroxyphenol
    • 4-Hydroxyphenol
    • p-Dihydroxybenzene
    • Benzoquinol
    • hydroquinol
    • Dihydroquinone
    • Eldoquin
    • p-Dioxybenzene
    • Solaquin forte
    • Eldopaque
    • Hydroquinole
    • Idrochinone
    • Tecquinol
    • Phiaquin
    • Benzohydroquinone
    • Hidroquinone
    • Arctuvin
    • Tequinol
    • Dihydroxybenzene
    • Eldopaque Forte
    • Eldoquin Forte
    • Derma-Blanch
    • Hydrochinon
    • Tenox HQ
    • Diak 5
    • Benzene, p-dihydroxy-
    • Hydrochinone
    • 1,4-Dihydroxy-benzol
    • Artra
    • Usaf ek-356
    • 1,4-Diidrobenzene
    • p-Dioxobenzene
    • 1,4-Dihydroxybenzen
    • para-Dioxybenzene
    • para-Hydroquinone
    • NCI-C55834
    • Black and White Bleaching Cream
    • 1,4-Dihydroxy-benzeen
    • para-Dihydroxybenzene
    • beta-quinol
    • HE 5
    • Pyrogentistic acid
    • Epiquin
    • Melanex
    • Sunvanish
    • Idrochinone [Italian]
    • p-Dihydroquinone
    • alpha-hydroquinone
    • CHEBI:17594
    • NSC 9247
    • Hydrochinon [Czech, Polish]
    • CCRIS 714
    • 1,4-Dihydroxybenzen [Czech]
    • 1,4-Diidrobenzene [Italian]
    • HSDB 577
    • DTXSID7020716
    • 1,4-Dihydroxy-benzeen [Dutch]
    • 1,4-Dihydroxy-benzol [German]
    • AI3-00072
    • CHEMBL537
    • UNII-XV74C1N1AE
    • NSC-9247
    • EINECS 204-617-8
    • XV74C1N1AE
    • MFCD00002339
    • UN2662
    • Hydroquinone (USP)
    • Hydroquinone [USP]
    • HQ
    • DTXCID70716
    • NSC9247
    • EC 204-617-8
    • Hydroquinone [UN2662] [Poison]
    • 1,4-Dihydroxybenzene (ring-d4)
    • TRI-LUMA COMPONENT HYDROQUINONE
    • NCGC00015523-02
    • HYDROQUINONE (IARC)
    • HYDROQUINONE [IARC]
    • para-Hydroxyphenol
    • Quinol; 1,4-Benzenediol; 1,4-Dihydroxybenzene
    • HYDROQUINONE (MART.)
    • HYDROQUINONE [MART.]
    • HYDROQUINONE (USP-RS)
    • HYDROQUINONE [USP-RS]
    • quinnone
    • Eldopacque
    • p-Phenylenediol
    • p Benzendiol
    • HYDROQUINONE (USP MONOGRAPH)
    • HYDROQUINONE [USP MONOGRAPH]
    • p-Quinol
    • 1,4-Benzoquinol
    • CAS-123-31-9
    • SMR000059154
    • 1,4-Hydroxybenzene
    • SR-01000075920
    • BUTYLHYDROXYANISOLE IMPURITY A (EP IMPURITY)
    • BUTYLHYDROXYANISOLE IMPURITY A [EP IMPURITY]
    • 4-DIHYDROXYBENZENE
    • hydroquinon
    • BQ(H)
    • Hydroquinoue
    • Balancer
    • MedisilkeNight
    • Supermax
    • hydroq uinone
    • hydroquinone gr
    • MiracleFade
    • Reduced quinone
    • a-Hydroquinone
    • Activator Light
    • Corrector Light
    • Skin Lightener
    • Black & White Bleaching Cream
    • Clear Action
    • Double White
    • Exence White
    • Hydroquinone gel
    • Idole Carrot
    • Movate Carrot

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 176.84
    methanol 273.21
    isopropanol 122.88
    water 16.74
    ethyl acetate 62.11
    n-propanol 117.17
    acetone 134.33
    n-butanol 89.69
    acetonitrile 75.86
    DMF 416.86
    toluene 3.23
    isobutanol 67.27
    1,4-dioxane 100.94
    methyl acetate 116.05
    THF 266.38
    2-butanone 94.98
    n-pentanol 70.74
    sec-butanol 83.7
    n-hexane 2.44
    ethylene glycol 88.68
    NMP 110.11
    cyclohexane 0.88
    DMSO 338.43
    n-butyl acetate 41.58
    n-octanol 39.8
    chloroform 38.08
    n-propyl acetate 47.78
    acetic acid 74.89
    dichloromethane 32.88
    cyclohexanone 49.11
    propylene glycol 82.84
    isopropyl acetate 36.6
    DMAc 302.52
    2-ethoxyethanol 178.32
    isopentanol 67.05
    n-heptane 3.85
    ethyl formate 98.61
    1,2-dichloroethane 28.55
    n-hexanol 68.78
    2-methoxyethanol 289.43
    isobutyl acetate 25.32
    tetrachloromethane 15.91
    n-pentyl acetate 30.67
    transcutol 126.64
    n-heptanol 44.55
    ethylbenzene 6.86
    MIBK 40.49
    2-propoxyethanol 150.76
    tert-butanol 123.88
    MTBE 61.87
    2-butoxyethanol 97.08
    propionic acid 73.62
    o-xylene 5.88
    formic acid 105.97
    diethyl ether 37.98
    m-xylene 5.14
    p-xylene 8.95
    chlorobenzene 7.33
    dimethyl carbonate 55.36
    n-octane 2.43
    formamide 193.21
    cyclopentanone 115.01
    2-pentanone 61.43
    anisole 39.36
    cyclopentyl methyl ether 43.26
    gamma-butyrolactone 145.0
    1-methoxy-2-propanol 171.87
    pyridine 33.14
    3-pentanone 32.3
    furfural 112.59
    n-dodecane 2.54
    diethylene glycol 150.03
    diisopropyl ether 11.44
    tert-amyl alcohol 94.65
    acetylacetone 71.58
    n-hexadecane 2.65
    acetophenone 34.85
    methyl propionate 64.88
    isopentyl acetate 36.68
    trichloroethylene 46.06
    n-nonanol 33.6
    cyclohexanol 24.4
    benzyl alcohol 32.55
    2-ethylhexanol 33.69
    isooctanol 32.91
    dipropyl ether 29.59
    1,2-dichlorobenzene 11.55
    ethyl lactate 42.38
    propylene carbonate 63.58
    n-methylformamide 250.09
    2-pentanol 46.64
    n-pentane 1.8
    1-propoxy-2-propanol 81.25
    1-methoxy-2-propyl acetate 53.25
    2-(2-methoxypropoxy) propanol 62.59
    mesitylene 4.98
    ε-caprolactone 52.16
    p-cymene 9.96
    epichlorohydrin 145.55
    1,1,1-trichloroethane 30.4
    2-aminoethanol 140.93
    morpholine-4-carbaldehyde 153.08
    sulfolane 128.4
    2,2,4-trimethylpentane 2.09
    2-methyltetrahydrofuran 90.0
    n-hexyl acetate 40.64
    isooctane 2.02
    2-(2-butoxyethoxy)ethanol 85.2
    sec-butyl acetate 26.89
    tert-butyl acetate 44.35
    decalin 1.77
    glycerin 120.03
    diglyme 170.3
    acrylic acid 58.81
    isopropyl myristate 17.32
    n-butyric acid 78.95
    acetyl acetate 33.22
    di(2-ethylhexyl) phthalate 17.93
    ethyl propionate 42.83
    nitromethane 224.06
    1,2-diethoxyethane 45.12
    benzonitrile 24.84
    trioctyl phosphate 17.31
    1-bromopropane 13.91
    gamma-valerolactone 143.78
    n-decanol 25.27
    triethyl phosphate 23.07
    4-methyl-2-pentanol 30.2
    propionitrile 63.88
    vinylene carbonate 55.21
    1,1,2-trichlorotrifluoroethane 112.97
    DMS 28.15
    cumene 8.06
    2-octanol 26.86
    2-hexanone 49.51
    octyl acetate 24.11
    limonene 11.33
    1,2-dimethoxyethane 245.13
    ethyl orthosilicate 23.6
    tributyl phosphate 17.07
    diacetone alcohol 84.7
    N,N-dimethylaniline 31.84
    acrylonitrile 81.6
    aniline 15.09
    1,3-propanediol 167.44
    bromobenzene 4.92
    dibromomethane 16.69
    1,1,2,2-tetrachloroethane 42.8
    2-methyl-cyclohexyl acetate 24.67
    tetrabutyl urea 25.09
    diisobutyl methanol 21.92
    2-phenylethanol 37.22
    styrene 6.24
    dioctyl adipate 22.06
    dimethyl sulfate 91.89
    ethyl butyrate 34.02
    methyl lactate 68.41
    butyl lactate 31.05
    diethyl carbonate 26.18
    propanediol butyl ether 69.2
    triethyl orthoformate 26.39
    p-tert-butyltoluene 10.77
    methyl 4-tert-butylbenzoate 43.61
    morpholine 125.13
    tert-butylamine 57.84
    n-dodecanol 18.84
    dimethoxymethane 181.35
    ethylene carbonate 45.15
    cyrene 51.71
    2-ethoxyethyl acetate 41.51
    2-ethylhexyl acetate 25.34
    1,2,4-trichlorobenzene 12.12
    4-methylpyridine 33.78
    dibutyl ether 25.84
    2,6-dimethyl-4-heptanol 21.92
    DEF 81.04
    dimethyl isosorbide 84.23
    tetrachloroethylene 32.52
    eugenol 51.19
    triacetin 30.34
    span 80 40.62
    1,4-butanediol 79.82
    1,1-dichloroethane 27.81
    2-methyl-1-pentanol 50.36
    methyl formate 186.62
    2-methyl-1-butanol 57.22
    n-decane 3.87
    butyronitrile 57.09
    3,7-dimethyl-1-octanol 31.72
    1-chlorooctane 14.25
    1-chlorotetradecane 6.03
    n-nonane 3.55
    undecane 3.03
    tert-butylcyclohexane 3.0
    cyclooctane 0.63
    cyclopentanol 48.74
    tetrahydropyran 48.08
    tert-amyl methyl ether 42.65
    2,5,8-trioxanonane 114.88
    1-hexene 9.62
    2-isopropoxyethanol 101.93
    2,2,2-trifluoroethanol 64.41
    methyl butyrate 66.26

    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
Ketaki (India) Pandanus fascicularis Lam., var. Ketaki, fam. Pandanaceae 6.1%