Toluidine Red

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  • Identifiers

    CAS number
    2425-85-6

    Molecular formula
    C17H13N3O3

    SMILES
    CC1=CC(=C(C=C1)N=NC2=C(C=CC3=CC=CC=C32)O)[N+](=O)[O-]

    Safety labels

    Corrosive
    Corrosive

    Environmental Hazard
    Environmental

  • Odor profile

    Fragrance
    Floral 40.85%
    Grape 37.1%
    Odorless 35.32%
    Fruity 35.11%
    Neroli 34.84%
    Sweet 33.96%
    Powdery 28.52%
    Bitter 28.09%
    Fatty 25.35%
    Orange 25.18%

     

    Flavor
    Bitter 90.55%
    Odorless 35.73%
    Nitrile 21.12%
    Very strong 20.51%
    Indole 20.11%
    Mild 19.91%
    Sweet-like 19.49%
    Bland 19.47%
    Bread crust 19.04%
    Cedarleaf 18.98%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    4.8

    pKa est.
    8.47 (weak base)

    Molecular weight
    307.3 g/mol

    Melting point expt.

    • 518 to 522 °F (NTP, 1992)
    • 270 to 272 °C

    Flash point

    • 246.94 ˚C est.

    Solubility expt.

    • less than 1 mg/mL at 72 °F (NTP, 1992)
    • Slightly soluble in ethanol and xylene; poorly soluble in ethers and ketones.
    • Slightly soluble in water(0.8 g/L) ethanol(0.7 g/L), ethylene glycol methyl ether(0.9 g/L), acetone, and benzene; very soluble in mineral spirits, aromatic hydrocarbons and plasticizers.

  • Synonyms

    • 2425-85-6
    • Toluidine red
    • Hansa Red B
    • Permanent Red 4R
    • Fast Red R
    • Toluidine Toner
    • Independence Red
    • Helio Fast Red RN
    • Chromatex Red J
    • Helio Red Toner
    • Toluidine Red R
    • Deep Fastona Red
    • Fastona Red B
    • Silosol Red RN
    • Hansa Scarlet RB
    • Hansa Scarlet RN
    • Siegle Red B
    • Silosol Red RBN
    • Siloton Red RLL
    • Siegle Red BB
    • Hansa Red G
    • Helio Red RL
    • Oralith Red P4R
    • Toluidine Red 3B
    • Toluidine Red 4R
    • Carnelio Helio Red
    • Eljon Fast Scarlet RN
    • Fast Red AB
    • Fast Red J
    • Fast Red JE
    • Hansa Scarlet RNC
    • Sanyo Scarlet Pure
    • Siegle Red 1
    • Silogomma Red RLL
    • Siloton Red BRLL
    • Toluidine Red BFB
    • Fastona Scarlet RL
    • Fastona Scarlet YS
    • Irgalite Red RNPX
    • Isol Fast Red HB
    • Toluidine Red Light
    • Toluidine Red Toner
    • Irgalite Scarlet RB
    • Helio Fast Red BN
    • Helio Fast Red RL
    • Lake Red 4R
    • Lake Red 4RII
    • Toluidine Red BFGG
    • Basoflex Red 361
    • Isol Fast Red RNB
    • Isol Fast Red RNG
    • Adc Toluidine Red B
    • Segnale Light Red B
    • Graphtol Red A-4RL
    • Lutetia Fast Red 3R
    • Enialit Light Red RL
    • Recolite Fast Red RL
    • Segnale Light Red BR
    • Segnale Light Red RL
    • Kromon Helio Fast Red
    • Isol Toluidine Red HB
    • Segnale Light Red 2B
    • Syton Fast Scarlet RB
    • Syton Fast Scarlet RD
    • Syton Fast Scarlet RN
    • Accosperse Toluidine Red XL
    • Recolite Fast Red RBL
    • Recolite Fast Red RYL
    • Irgalite Red PV2
    • Lithol Fast Scarlet RN
    • Isol Toluidine Red RNB
    • Isol Toluidine Red RNG
    • Lutetia Fast Scarlet RF
    • 2-Naphthalenol, 1-[(4-methyl-2-nitrophenyl)azo]-
    • Toluidine Red 10451
    • Symuler Fast Scarlet 4R
    • Toluidine Red RT-115
    • Hispalit Fast Scarlet RN
    • Monolite Fast Scarlet CA
    • Monolite Fast Scarlet RB
    • Monolite Fast Scarlet RN
    • Monolite Fast Scarlet RT
    • No. 2 Forthfast Scarlet
    • Lutetia Fast Scarlet RJN
    • Irgalite Fast Scarlet RND
    • Kromon Helio Fast Red YS
    • Monolite Fast Scarlet GSA
    • Monolite Fast Scarlet RBA
    • Monolite Fast Scarlet RNA
    • Monolite Fast Scarlet RNV
    • 1-(o-Nitro-p-tolylazo)-2-naphthol
    • Calcotone Toluidine Red YP
    • D and C Red No. 35
    • Isol Fast Red RN2B
    • Isol Fast Red RN2G
    • Dainichi Permanent Red 4 R
    • Eljon Fast Scarlet PV Extra
    • C.I. 12120
    • Irgalite Fast Red P4R
    • Segnale Light Red C4R
    • Vulcafor Scarlet A
    • Toluidine Red D 28-3930
    • Toluidine Red M 20-3785
    • Isol Toluidine Red RN2B
    • Isol Toluidine Red RN2G
    • Toluidine Red XL 20-3050
    • Sanyo Scarlet Pure No. 1000
    • Versal Scarlet PRNL
    • NCI-C60366
    • Recolite Fast Red BL
    • Duplex Toluidine Red L 20-3140
    • Fast Red A
    • Versal Scarlet RNL
    • CP Toluidine toner A-2989
    • Toluidine Toner L 20-3300
    • 1-((4-Methyl-2-nitrophenyl)azo)-2-naphthalenol
    • C.P. Toluidine Toner A-2989
    • C.P. Toluidine Toner A-2990
    • CI 12120
    • C.P. Toluidine Toner RT-6101
    • C.I.12120
    • 1-((2-Nitro-4-methylphenyl)azo)-2-naphthol
    • Toluidine Toner Dark 5040
    • C.P. Toluidine Toner Deep X-1865
    • C.P. Toluidine Toner Dark RS-3340
    • C.P. Toluidine Toner Light RS-3140
    • 2-Naphthalenol, 1-((4-methyl-2-nitrophenyl)azo)-
    • 2425-85-6

  • Applications

    Toluidine Red (CAS 2425-85-6) is primarily used as a synthetic dye and pigment precursor. In industry, it serves as a colorant for textiles and printing inks, and is incorporated into coating and paint systems to deliver stable coloration. It is also used as a staining/analytic dye in laboratory applications and may act as a colorant for plastics and polymer matrices. In addition, it is commonly regarded as an intermediate in dye synthesis and pigment production, supporting color-related applications across several industrial sectors.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 1.87
    methanol 1.88
    isopropanol 1.17
    water 0.0
    ethyl acetate 17.95
    n-propanol 2.06
    acetone 29.18
    n-butanol 1.71
    acetonitrile 7.34
    DMF 36.24
    toluene 15.45
    isobutanol 1.26
    1,4-dioxane 33.65
    methyl acetate 26.49
    THF 135.4
    2-butanone 36.25
    n-pentanol 2.21
    sec-butanol 1.88
    n-hexane 0.1
    ethylene glycol 0.48
    NMP 26.68
    cyclohexane 0.13
    DMSO 34.29
    n-butyl acetate 18.28
    n-octanol 1.32
    chloroform 30.75
    n-propyl acetate 13.94
    acetic acid 6.91
    dichloromethane 45.28
    cyclohexanone 30.98
    propylene glycol 0.86
    isopropyl acetate 12.71
    DMAc 66.59
    2-ethoxyethanol 11.74
    isopentanol 2.27
    n-heptane 0.19
    ethyl formate 6.4
    1,2-dichloroethane 35.98
    n-hexanol 3.15
    2-methoxyethanol 17.02
    isobutyl acetate 9.29
    tetrachloromethane 0.73
    n-pentyl acetate 9.23
    transcutol 92.09
    n-heptanol 1.97
    ethylbenzene 5.46
    MIBK 12.61
    2-propoxyethanol 21.35
    tert-butanol 3.07
    MTBE 7.95
    2-butoxyethanol 10.79
    propionic acid 3.71
    o-xylene 5.7
    formic acid 1.71
    diethyl ether 6.54
    m-xylene 6.12
    p-xylene 6.92
    chlorobenzene 13.33
    dimethyl carbonate 13.86
    n-octane 0.13
    formamide 5.64
    cyclopentanone 61.69
    2-pentanone 19.19
    anisole 20.07
    cyclopentyl methyl ether 13.67
    gamma-butyrolactone 51.84
    1-methoxy-2-propanol 12.88
    pyridine 52.15
    3-pentanone 16.26
    furfural 47.76
    n-dodecane 0.19
    diethylene glycol 12.06
    diisopropyl ether 2.12
    tert-amyl alcohol 3.35
    acetylacetone 48.71
    n-hexadecane 0.23
    acetophenone 20.88
    methyl propionate 17.06
    isopentyl acetate 18.66
    trichloroethylene 107.78
    n-nonanol 1.89
    cyclohexanol 2.12
    benzyl alcohol 9.48
    2-ethylhexanol 3.14
    isooctanol 2.14
    dipropyl ether 6.93
    1,2-dichlorobenzene 12.72
    ethyl lactate 6.24
    propylene carbonate 16.75
    n-methylformamide 8.94
    2-pentanol 1.36
    n-pentane 0.06
    1-propoxy-2-propanol 14.85
    1-methoxy-2-propyl acetate 35.2
    2-(2-methoxypropoxy) propanol 22.77
    mesitylene 2.9
    ε-caprolactone 23.66
    p-cymene 3.91
    epichlorohydrin 125.36
    1,1,1-trichloroethane 18.25
    2-aminoethanol 1.23
    morpholine-4-carbaldehyde 40.13
    sulfolane 52.39
    2,2,4-trimethylpentane 0.16
    2-methyltetrahydrofuran 25.42
    n-hexyl acetate 9.17
    isooctane 0.14
    2-(2-butoxyethoxy)ethanol 26.7
    sec-butyl acetate 10.81
    tert-butyl acetate 21.71
    decalin 0.33
    glycerin 2.44
    diglyme 68.7
    acrylic acid 4.94
    isopropyl myristate 6.54
    n-butyric acid 5.46
    acetyl acetate 14.43
    di(2-ethylhexyl) phthalate 6.89
    ethyl propionate 13.77
    nitromethane 41.78
    1,2-diethoxyethane 34.85
    benzonitrile 14.04
    trioctyl phosphate 3.5
    1-bromopropane 8.73
    gamma-valerolactone 78.03
    n-decanol 1.65
    triethyl phosphate 8.52
    4-methyl-2-pentanol 1.63
    propionitrile 7.15
    vinylene carbonate 16.46
    1,1,2-trichlorotrifluoroethane 31.73
    DMS 23.65
    cumene 3.22
    2-octanol 1.29
    2-hexanone 18.83
    octyl acetate 6.66
    limonene 4.12
    1,2-dimethoxyethane 44.39
    ethyl orthosilicate 7.39
    tributyl phosphate 5.78
    diacetone alcohol 22.02
    N,N-dimethylaniline 9.85
    acrylonitrile 15.95
    aniline 10.09
    1,3-propanediol 2.71
    bromobenzene 16.77
    dibromomethane 16.8
    1,1,2,2-tetrachloroethane 52.93
    2-methyl-cyclohexyl acetate 13.17
    tetrabutyl urea 9.28
    diisobutyl methanol 3.24
    2-phenylethanol 13.73
    styrene 7.65
    dioctyl adipate 12.24
    dimethyl sulfate 21.85
    ethyl butyrate 14.15
    methyl lactate 8.78
    butyl lactate 7.78
    diethyl carbonate 10.07
    propanediol butyl ether 6.69
    triethyl orthoformate 10.83
    p-tert-butyltoluene 3.8
    methyl 4-tert-butylbenzoate 17.35
    morpholine 30.14
    tert-butylamine 1.29
    n-dodecanol 1.44
    dimethoxymethane 32.66
    ethylene carbonate 10.83
    cyrene 16.36
    2-ethoxyethyl acetate 25.16
    2-ethylhexyl acetate 14.45
    1,2,4-trichlorobenzene 20.39
    4-methylpyridine 30.42
    dibutyl ether 6.39
    2,6-dimethyl-4-heptanol 3.24
    DEF 17.48
    dimethyl isosorbide 58.53
    tetrachloroethylene 19.51
    eugenol 19.11
    triacetin 17.71
    span 80 11.16
    1,4-butanediol 0.97
    1,1-dichloroethane 16.68
    2-methyl-1-pentanol 3.39
    methyl formate 10.84
    2-methyl-1-butanol 1.97
    n-decane 0.23
    butyronitrile 5.11
    3,7-dimethyl-1-octanol 3.23
    1-chlorooctane 1.73
    1-chlorotetradecane 1.09
    n-nonane 0.16
    undecane 0.21
    tert-butylcyclohexane 0.36
    cyclooctane 0.07
    cyclopentanol 2.52
    tetrahydropyran 17.9
    tert-amyl methyl ether 7.74
    2,5,8-trioxanonane 51.5
    1-hexene 1.18
    2-isopropoxyethanol 8.26
    2,2,2-trifluoroethanol 2.03
    methyl butyrate 16.24

    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