Phenol red sodium

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  • Identifiers

    CAS number
    34487-61-1

    Molecular formula
    C19H13NaO5S

    SMILES
    C1=CC=C(C(=C1)C(=C2C=CC(=O)C=C2)C3=CC=C(C=C3)O)S(=O)(=O)[O-].[Na+]

    Safety labels

  • Odor profile

    Fragrance
    Odorless 56.77%
    Bitter 24.35%
    Burnt 23.9%
    Cooked 22.4%
    Fruity 22.0%
    Savory 21.3%
    Roasted 20.0%
    Spicy 19.74%
    Nutty 18.47%
    Phenolic 17.22%

     

    Flavor
    Bitter 89.04%
    Odorless 24.23%
    Nitrile 20.28%
    Lovage 18.37%
    Very strong 18.17%
    Indole 17.84%
    Bread crust 17.61%
    Taco 17.59%
    Oriental 17.5%
    Cedarleaf 17.41%

     

    Odor impact est.
    Low

  • Properties

    pKa est.
    5.28 (weak acid)

    Molecular weight
    376.4 g/mol

    Flash point

    • 226.48 ˚C est.

  • Synonyms

    • Phenolsulfonephthalein sodium
    • 50J9732WBG
    • phenol red sodium
    • RefChem:860617
    • 252-057-8
    • 34487-61-1
    • Phenol, 4,4'-(3H-2,1-benzoxathiol-3-ylidene)bis-, S,S-dioxide, monosodium salt
    • Phenol Red (sodium salt)
    • Sodium Phenol Red
    • sodium;2-[(4-hydroxyphenyl)-(4-oxocyclohexa-2,5-dien-1-ylidene)methyl]benzenesulfonate
    • SCHEMBL16371054
    • SBB005409
    • AKOS015964088
    • AKOS024282608
    • PHENOLSULFONPHTHALEIN SODIUM SALT
    • AC-18339
    • ST057217
    • P0102
    • PHENOLSULFONPHTHALEIN SODIUM SALT [MI]
    • P-2850
    • Q27260797
    • PHENOL, 4,4'-(1,1-DIOXIDO-3H-2,1-BENZOXATHIOL-3-YLIDENE)BIS-, SODIUM
    • sodium,4-[3-(4-hydroxyphenyl)-1,1-dioxo-2,1lambda6-benzoxathiol-3-yl]phenolate
    • 1007195-14-3
    • BENZENESULFONIC ACID, 2-((4-HYDROXYPHENYL)(4-OXO-2,5-CYCLOHEXADIEN-1-YLIDENE)METHYL)-, SODIUM SALT (1:1)
    • 34487-61-1

  • Applications

    Phenol red sodium, CAS 34487-61-1, is a pH indicator dye primarily used in microbiology and cell culture media to visualize pH changes during growth and to adjust formulation conditions. It also serves as a pH indicator in analytical chemistry and in buffer systems for monitoring pH shifts in quantitative methods and titration. In biotech and bioprocess workflows, it can function as a colorimetric indicator to monitor fermentation and process parameters. Additionally, Phenol red sodium is employed in educational laboratory kits to visually demonstrate pH changes and as a dye in certain analytical colorimetric assays. Use is subject to local regulations and formulation limits.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 1.96
    methanol 2.4
    isopropanol 0.73
    water 0.01
    ethyl acetate 4.89
    n-propanol 1.82
    acetone 6.38
    n-butanol 1.25
    acetonitrile 3.9
    DMF 70.81
    toluene 3.55
    isobutanol 0.85
    1,4-dioxane 12.17
    methyl acetate 7.11
    THF 36.16
    2-butanone 14.1
    n-pentanol 0.94
    sec-butanol 1.87
    n-hexane 0.01
    ethylene glycol 1.62
    NMP 75.99
    cyclohexane 0.04
    DMSO 30.63
    n-butyl acetate 5.84
    n-octanol 1.1
    chloroform 3.66
    n-propyl acetate 4.51
    acetic acid 4.3
    dichloromethane 5.31
    cyclohexanone 20.33
    propylene glycol 2.55
    isopropyl acetate 4.21
    DMAc 109.21
    2-ethoxyethanol 8.86
    isopentanol 1.01
    n-heptane 0.03
    ethyl formate 3.78
    1,2-dichloroethane 4.91
    n-hexanol 1.48
    2-methoxyethanol 21.97
    isobutyl acetate 2.0
    tetrachloromethane 0.14
    n-pentyl acetate 4.64
    transcutol 31.89
    n-heptanol 1.52
    ethylbenzene 1.41
    MIBK 3.62
    2-propoxyethanol 14.89
    tert-butanol 0.89
    MTBE 1.55
    2-butoxyethanol 9.04
    propionic acid 4.18
    o-xylene 2.14
    formic acid 4.49
    diethyl ether 1.59
    m-xylene 1.3
    p-xylene 1.28
    chlorobenzene 3.11
    dimethyl carbonate 10.06
    n-octane 0.02
    formamide 16.24
    cyclopentanone 38.57
    2-pentanone 6.47
    anisole 9.45
    cyclopentyl methyl ether 6.17
    gamma-butyrolactone 36.29
    1-methoxy-2-propanol 15.5
    pyridine 25.32
    3-pentanone 6.78
    furfural 33.13
    n-dodecane 0.03
    diethylene glycol 11.87
    diisopropyl ether 0.38
    tert-amyl alcohol 2.09
    acetylacetone 13.89
    n-hexadecane 0.04
    acetophenone 11.98
    methyl propionate 9.49
    isopentyl acetate 4.94
    trichloroethylene 18.1
    n-nonanol 1.35
    cyclohexanol 2.16
    benzyl alcohol 7.68
    2-ethylhexanol 1.5
    isooctanol 1.29
    dipropyl ether 2.09
    1,2-dichlorobenzene 3.27
    ethyl lactate 6.6
    propylene carbonate 11.39
    n-methylformamide 18.57
    2-pentanol 0.85
    n-pentane 0.01
    1-propoxy-2-propanol 10.52
    1-methoxy-2-propyl acetate 15.59
    2-(2-methoxypropoxy) propanol 14.47
    mesitylene 0.67
    ε-caprolactone 18.25
    p-cymene 1.38
    epichlorohydrin 41.62
    1,1,1-trichloroethane 1.3
    2-aminoethanol 3.49
    morpholine-4-carbaldehyde 60.78
    sulfolane 56.01
    2,2,4-trimethylpentane 0.03
    2-methyltetrahydrofuran 10.41
    n-hexyl acetate 5.15
    isooctane 0.01
    2-(2-butoxyethoxy)ethanol 15.46
    sec-butyl acetate 3.5
    tert-butyl acetate 5.57
    decalin 0.05
    glycerin 8.45
    diglyme 29.91
    acrylic acid 6.45
    isopropyl myristate 2.33
    n-butyric acid 3.95
    acetyl acetate 4.83
    di(2-ethylhexyl) phthalate 4.37
    ethyl propionate 5.47
    nitromethane 19.05
    1,2-diethoxyethane 7.46
    benzonitrile 7.98
    trioctyl phosphate 2.36
    1-bromopropane 1.01
    gamma-valerolactone 54.37
    n-decanol 1.01
    triethyl phosphate 4.22
    4-methyl-2-pentanol 0.59
    propionitrile 4.04
    vinylene carbonate 11.45
    1,1,2-trichlorotrifluoroethane 31.42
    DMS 11.2
    cumene 0.84
    2-octanol 0.9
    2-hexanone 4.77
    octyl acetate 3.3
    limonene 1.75
    1,2-dimethoxyethane 19.94
    ethyl orthosilicate 3.65
    tributyl phosphate 2.78
    diacetone alcohol 10.52
    N,N-dimethylaniline 5.91
    acrylonitrile 9.81
    aniline 7.68
    1,3-propanediol 3.91
    bromobenzene 2.49
    dibromomethane 1.67
    1,1,2,2-tetrachloroethane 11.03
    2-methyl-cyclohexyl acetate 5.77
    tetrabutyl urea 5.8
    diisobutyl methanol 0.93
    2-phenylethanol 8.64
    styrene 2.03
    dioctyl adipate 5.65
    dimethyl sulfate 22.02
    ethyl butyrate 5.77
    methyl lactate 14.02
    butyl lactate 6.87
    diethyl carbonate 4.31
    propanediol butyl ether 7.86
    triethyl orthoformate 5.32
    p-tert-butyltoluene 1.19
    methyl 4-tert-butylbenzoate 12.03
    morpholine 20.23
    tert-butylamine 0.39
    n-dodecanol 0.74
    dimethoxymethane 21.8
    ethylene carbonate 7.18
    cyrene 18.06
    2-ethoxyethyl acetate 11.08
    2-ethylhexyl acetate 4.33
    1,2,4-trichlorobenzene 7.05
    4-methylpyridine 17.33
    dibutyl ether 1.51
    2,6-dimethyl-4-heptanol 0.93
    DEF 20.89
    dimethyl isosorbide 28.68
    tetrachloroethylene 4.7
    eugenol 13.32
    triacetin 10.91
    span 80 9.61
    1,4-butanediol 1.23
    1,1-dichloroethane 1.43
    2-methyl-1-pentanol 1.21
    methyl formate 10.87
    2-methyl-1-butanol 1.53
    n-decane 0.06
    butyronitrile 2.73
    3,7-dimethyl-1-octanol 1.24
    1-chlorooctane 0.49
    1-chlorotetradecane 0.23
    n-nonane 0.04
    undecane 0.04
    tert-butylcyclohexane 0.03
    cyclooctane 0.02
    cyclopentanol 2.93
    tetrahydropyran 6.05
    tert-amyl methyl ether 2.56
    2,5,8-trioxanonane 23.06
    1-hexene 0.14
    2-isopropoxyethanol 5.55
    2,2,2-trifluoroethanol 2.31
    methyl butyrate 6.7

    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