4-(Phenylazo)resorcinol

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  • Identifiers

    CAS number
    2051-85-6

    Molecular formula
    C12H10N2O2

    SMILES
    C1=CC=C(C=C1)N=NC2=C(C=C(C=C2)O)O

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 41.08%
    Phenolic 36.07%
    Burnt 32.12%
    Bitter 30.33%
    Meaty 29.2%
    Spicy 27.25%
    Sweet 26.11%
    Savory 25.98%
    Smoky 24.76%
    Vanilla 22.89%

     

    Flavor
    Bitter 81.66%
    Odorless 26.25%
    Mild 25.13%
    Nitrile 22.43%
    Very strong 21.65%
    Indole 20.97%
    Scallion 20.86%
    Bread crust 20.67%
    Moth ball 20.24%
    Taco 20.24%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    3.0

    pKa est.
    9.36 (weak base)

    Molecular weight
    214.22 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    415°C

    Flash point

    • 200.61 ˚C est.

  • Synonyms

    • 2,4-Dihydroxyazobenzene
    • 4-(PHENYLAZO)RESORCINOL
    • 1,3-Benzenediol, 4-(phenylazo)-
    • 1,3-Benzenediol, 4-(2-phenyldiazenyl)-
    • RefChem:516611
    • Sudan Orange G
    • 2051-85-6
    • Solvent orange 1
    • Ceres Orange G
    • Ceres Orange GN
    • Sudan G
    • Fat Orange A
    • Benzeneazoresorcinol
    • C.I. Solvent Orange 1
    • Sudan Yellow AR
    • Resinol Orange G
    • Fat Orange GS
    • Fat Orange RG
    • Cerisol Yellow GR
    • Grasol Yellow RSF
    • Organol Orange 2J
    • Tertrogras Orange SG
    • Fat Victoria Yellow D
    • 1504 Yellow
    • C.I. Food Orange 3
    • p-Phenylazoresorcinol
    • 2,4-Dibenzeneazoresorcinol
    • Yellow M Soluble in Grease
    • Lacquer Orange V 3G
    • Resorcinol, 4-(phenylazo)-
    • Plastoresin Orange F 3A
    • CI 11920
    • 4-Phenylazoresorcinol
    • Oranz potravinarska 3
    • C.I. 11920
    • Oranz rozpoustedlova 1
    • NSC 7949
    • JR7B69ZW9B
    • (E)-4-(phenyldiazenyl)benzene-1,3-diol
    • 96627-69-9
    • 4-phenyldiazenylbenzene-1,3-diol
    • NSC-7949
    • 4-(phenyldiazenyl)benzene-1,3-diol
    • MFCD00002275
    • Sudan Orange G (~85%)
    • Food Orange 3
    • Oranz potravinarska 3 [Czech]
    • Oranz rozpoustedlova 1 [Czech]
    • 4-(Phenylazo)-1,3-benzenediol
    • EINECS 218-131-9
    • UNII-JR7B69ZW9B
    • BRN 0958430
    • 4-(2-phenyldiazen-1-yl)benzene-1,3-diol
    • AI3-08923
    • Lacquer Orange V3G
    • Dye content 85 %
    • Plastoresin Orange F3A
    • starbld0000655
    • SCHEMBL80799
    • 4-16-00-00264 (Beilstein Handbook Reference)
    • 4-phenylazobenzene-1,3-diol
    • SCHEMBL341192
    • SCHEMBL344165
    • orb1685398
    • orb3025074
    • DTXSID9062146
    • SCHEMBL29411152
    • MSK2410
    • NSC7949
    • Sudan Orange G C.I. 11920
    • Sudan Orange G, analytical standard
    • CCG-46686
    • Sudan Orange G, Dye content 85 %
    • Sudan Orange G, >=97% (HPLC)
    • AKOS000121075
    • AKOS030241188
    • AKOS037955973
    • 4-(Phenyldiazenyl)-1,3-benzenediol #
    • HY-119987
    • CS-0078870
    • NS00046470
    • ST50411577
    • 1,3-BENZENEDIOL, 4-(PHENYLAZO)-, (E)-
    • SR-01000636365-1
    • Q27281644
    • 2051-85-6

  • Applications

    4-(Phenylazo)resorcinol (CAS 2051-85-6) is commonly used as an azo dye intermediate in the synthesis of azo dyes; in industrial practice, it serves as a dyeing precursor for textiles and leather and can be used to color plastics and coatings, while also functioning as a colorant precursor for inks and printing formulations and potentially incorporated into polymer systems to impart coloration.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 53.12
    methanol 49.34
    isopropanol 36.14
    water 0.01
    ethyl acetate 124.74
    n-propanol 36.41
    acetone 92.87
    n-butanol 28.62
    acetonitrile 76.78
    DMF 39.76
    toluene 11.58
    isobutanol 17.03
    1,4-dioxane 140.14
    methyl acetate 105.61
    THF 409.27
    2-butanone 135.14
    n-pentanol 23.53
    sec-butanol 40.53
    n-hexane 0.12
    ethylene glycol 9.19
    NMP 20.26
    cyclohexane 0.19
    DMSO 417.02
    n-butyl acetate 43.06
    n-octanol 7.15
    chloroform 8.28
    n-propyl acetate 45.48
    acetic acid 61.67
    dichloromethane 5.43
    cyclohexanone 56.81
    propylene glycol 40.67
    isopropyl acetate 65.64
    DMAc 114.77
    2-ethoxyethanol 90.16
    isopentanol 29.93
    n-heptane 0.33
    ethyl formate 37.62
    1,2-dichloroethane 15.44
    n-hexanol 18.13
    2-methoxyethanol 215.66
    isobutyl acetate 24.19
    tetrachloromethane 0.65
    n-pentyl acetate 15.38
    transcutol 792.26
    n-heptanol 7.87
    ethylbenzene 4.45
    MIBK 53.14
    2-propoxyethanol 89.82
    tert-butanol 54.28
    MTBE 43.95
    2-butoxyethanol 39.07
    propionic acid 38.02
    o-xylene 4.94
    formic acid 16.93
    diethyl ether 36.96
    m-xylene 6.04
    p-xylene 5.13
    chlorobenzene 8.37
    dimethyl carbonate 30.27
    n-octane 0.13
    formamide 69.32
    cyclopentanone 88.83
    2-pentanone 80.9
    anisole 37.7
    cyclopentyl methyl ether 50.44
    gamma-butyrolactone 119.2
    1-methoxy-2-propanol 183.29
    pyridine 80.31
    3-pentanone 42.87
    furfural 95.92
    n-dodecane 0.37
    diethylene glycol 83.11
    diisopropyl ether 7.95
    tert-amyl alcohol 48.17
    acetylacetone 156.67
    n-hexadecane 0.43
    acetophenone 34.62
    methyl propionate 73.18
    isopentyl acetate 41.81
    trichloroethylene 43.15
    n-nonanol 8.39
    cyclohexanol 18.02
    benzyl alcohol 28.47
    2-ethylhexanol 12.7
    isooctanol 8.34
    dipropyl ether 21.38
    1,2-dichlorobenzene 7.31
    ethyl lactate 32.48
    propylene carbonate 60.35
    n-methylformamide 37.89
    2-pentanol 22.51
    n-pentane 0.11
    1-propoxy-2-propanol 72.58
    1-methoxy-2-propyl acetate 82.69
    2-(2-methoxypropoxy) propanol 80.46
    mesitylene 3.6
    ε-caprolactone 61.78
    p-cymene 5.06
    epichlorohydrin 207.44
    1,1,1-trichloroethane 9.2
    2-aminoethanol 31.93
    morpholine-4-carbaldehyde 79.03
    sulfolane 124.11
    2,2,4-trimethylpentane 0.44
    2-methyltetrahydrofuran 104.57
    n-hexyl acetate 23.77
    isooctane 0.43
    2-(2-butoxyethoxy)ethanol 129.12
    sec-butyl acetate 34.79
    tert-butyl acetate 72.53
    decalin 0.4
    glycerin 60.16
    diglyme 234.2
    acrylic acid 31.69
    isopropyl myristate 14.32
    n-butyric acid 58.36
    acetyl acetate 57.6
    di(2-ethylhexyl) phthalate 13.61
    ethyl propionate 43.27
    nitromethane 209.49
    1,2-diethoxyethane 108.05
    benzonitrile 25.19
    trioctyl phosphate 8.55
    1-bromopropane 4.26
    gamma-valerolactone 139.23
    n-decanol 6.94
    triethyl phosphate 19.36
    4-methyl-2-pentanol 17.05
    propionitrile 38.85
    vinylene carbonate 40.7
    1,1,2-trichlorotrifluoroethane 106.83
    DMS 37.21
    cumene 3.46
    2-octanol 4.46
    2-hexanone 44.21
    octyl acetate 15.98
    limonene 6.7
    1,2-dimethoxyethane 173.3
    ethyl orthosilicate 17.38
    tributyl phosphate 13.63
    diacetone alcohol 106.3
    N,N-dimethylaniline 17.38
    acrylonitrile 53.89
    aniline 29.87
    1,3-propanediol 57.5
    bromobenzene 6.23
    dibromomethane 2.81
    1,1,2,2-tetrachloroethane 39.93
    2-methyl-cyclohexyl acetate 26.54
    tetrabutyl urea 17.84
    diisobutyl methanol 11.92
    2-phenylethanol 26.87
    styrene 6.43
    dioctyl adipate 26.45
    dimethyl sulfate 48.42
    ethyl butyrate 39.14
    methyl lactate 57.65
    butyl lactate 24.45
    diethyl carbonate 27.55
    propanediol butyl ether 50.59
    triethyl orthoformate 28.8
    p-tert-butyltoluene 5.31
    methyl 4-tert-butylbenzoate 34.11
    morpholine 186.79
    tert-butylamine 16.65
    n-dodecanol 5.72
    dimethoxymethane 124.6
    ethylene carbonate 31.83
    cyrene 47.56
    2-ethoxyethyl acetate 46.52
    2-ethylhexyl acetate 25.54
    1,2,4-trichlorobenzene 13.92
    4-methylpyridine 42.42
    dibutyl ether 19.31
    2,6-dimethyl-4-heptanol 11.92
    DEF 48.03
    dimethyl isosorbide 107.75
    tetrachloroethylene 13.27
    eugenol 35.98
    triacetin 48.48
    span 80 44.96
    1,4-butanediol 12.92
    1,1-dichloroethane 8.5
    2-methyl-1-pentanol 25.73
    methyl formate 32.89
    2-methyl-1-butanol 24.7
    n-decane 0.43
    butyronitrile 34.6
    3,7-dimethyl-1-octanol 13.34
    1-chlorooctane 2.84
    1-chlorotetradecane 1.79
    n-nonane 0.28
    undecane 0.41
    tert-butylcyclohexane 0.52
    cyclooctane 0.1
    cyclopentanol 20.75
    tetrahydropyran 82.49
    tert-amyl methyl ether 35.11
    2,5,8-trioxanonane 158.82
    1-hexene 1.41
    2-isopropoxyethanol 53.16
    2,2,2-trifluoroethanol 12.2
    methyl butyrate 51.6

    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