Rhein

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  • Identifiers

    CAS number
    478-43-3

    Molecular formula
    C15H8O6

    SMILES
    C1=CC2=C(C(=C1)O)C(=O)C3=C(C2=O)C=C(C=C3O)C(=O)O

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 63.93%
    Phenolic 43.16%
    Balsamic 28.31%
    Burnt 27.17%
    Bitter 26.53%
    Sweet 23.15%
    Nutty 21.25%
    Vanilla 20.07%
    Aromatic 19.9%
    Dry 19.52%

     

    Flavor
    Bitter 86.47%
    Odorless 36.81%
    Bland 20.7%
    Nitrile 20.69%
    Sweet-like 20.12%
    Lovage 20.02%
    Very strong 19.59%
    Cedarleaf 19.49%
    Indole 19.15%
    Urine 19.05%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    2.2

    pKa est.
    6.58 (neutral)

    Molecular weight
    284.22 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Melting point expt.

    • 610 °F (NTP, 1992)
    • >300
    • 321 °C

    Boiling point

    • Sublimes (NTP, 1992)

    Flash point

    • 299.63 ˚C est.

    Solubility expt.

    • less than 1 mg/mL at 63 °F (NTP, 1992)

  • Synonyms

    • Rhein
    • 478-43-3
    • Monorhein
    • Cassic acid
    • Rhubarb Yellow
    • Rheic acid
    • 4,5-Dihydroxyanthraquinone-2-carboxylic acid
    • Chrysazin-3-carboxylic acid
    • 1,8-Dihydroxyanthraquinone-3-carboxylic acid
    • 4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acid
    • 9,10-Dihydro-4,5-dihydroxy-9,10-dioxo-2-anthracenecarboxylic acid
    • DTXSID4026000
    • YM64C2P6UX
    • 2-Anthroic acid, 9,10-dihydro-4,5-dihydroxy-9,10-dioxo-
    • NSC-38629
    • DTXCID606000
    • 1,8-dihydroxy-3-carboxyl-9,10-anthraquinone
    • RefChem:882948
    • 207-521-4
    • 1,8-Dihydroxy-3-carboxyanthraquinone
    • 4,5-dihydroxy-9,10-dioxo-9,10-dihydroanthracene-2-carboxylic acid
    • MFCD00009618
    • NSC 38629
    • C15H8O6
    • 2-Anthracenecarboxylic acid, 9,10-dihydro-4,5-dihydroxy-9,10-dioxo-
    • 4,5-Dihydroxy-2-anthraquinonecarboxylic acid
    • MLS000069639
    • 4,5-DiOH-anthraquinone-2-COOH
    • Rhein (1,8-dihydroxy-3-carboxyl anthraquinone)
    • 9,10-Dihydro-4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acid
    • 4,5-dihydroxy-9,10-dioxo-anthracene-2-carboxylic acid
    • SMR000058210
    • ST057726
    • Rheinic acid
    • dipropionyl rhein
    • 9,10-Dihydro-4,5-dihydroxy-9,10-dioxo-2-anthroic acid
    • Parietic acid
    • Rhein(Monorhein)
    • CCRIS 5129
    • Diacerein EP Impurity C
    • EINECS 207-521-4
    • UNII-YM64C2P6UX
    • BRN 2222155
    • Monorhein;
    • Rhein (Standard)
    • Rhein CRS
    • RHN
    • Rhein; Rhubarb Yellow
    • Rhein, technical grade
    • 4ie7
    • regid855879
    • RHEIN [MI]
    • Rhein, analytical standard
    • SCHEMBL25253
    • Chrysazin-3-carboxyli c acid
    • Chrysazin-3-carboxylic acid;
    • US9238626, Rhein
    • 4-10-00-04088 (Beilstein Handbook Reference)
    • cid_10168
    • MLS006011744
    • CHEBI:8825
    • CHEMBL418068
    • MEGxp0_001866
    • orb1304757
    • SCHEMBL29404324
    • ACon1_000217
    • BDBM32021
    • HY-N0105R
    • GLXC-05271
    • HMS6018N16
    • BB_NC-02605
    • FDC16642
    • HY-N0105
    • MSK40045
    • NSC38629
    • Tox21_201098
    • 4,5-Dihydroxy-9,10-dioxo-9,10-dihydroanthracene-2-carboxylicacid
    • BBL009695
    • EBC-12623
    • LMPK13040015
    • s2400
    • SBB001152
    • STL141046
    • AKOS005259272
    • AC-7978
    • CS-5239
    • DB13174
    • FR27724
    • NCGC00018199-01
    • NCGC00018199-02
    • NCGC00018199-03
    • NCGC00018199-04
    • NCGC00018199-05
    • NCGC00018199-06
    • NCGC00018199-07
    • NCGC00018199-10
    • NCGC00023342-03
    • NCGC00023342-04
    • NCGC00258650-01
    • AS-11635
    • CAS-478-43-3
    • SY051290
    • DB-014981
    • D3986
    • NS00015851
    • 4, 5-Dihydroxyanthraquinone-2-carboxylic acid
    • 1,8-DIHYDROXY-3-CARBOXYL ANTHRAQUINONE
    • 2-Anthraquinonecarboxylic acid, 4,5-dihydroxy-
    • 78R433
    • EN300-303248
    • DIHYDROXY-3-CARBOXYLANTHRAQUINONE, 1,8-
    • F049599
    • Q720356
    • 4,5-dihydroxy-9,10-dioxo-2-anthracenecarboxylic acid
    • 4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylicacid
    • BRD-K27335680-001-01-9
    • BRD-K27335680-001-10-0
    • 2-Anthroic acid,10-dihydro-4,5-dihydroxy-9,10-dioxo-
    • 4,5-dihydroxy-9,10-diketo-anthracene-2-carboxylic acid
    • 2-Anthracenecarboxylic acid,10-dihydro-4,5-dihydroxy-9,10-dioxo-
    • 4,5-Dihydroxy-9,10-dioxo-9,10-dihydro-2-anthracenecarboxylic acid
    • 4,5-bis(oxidanyl)-9,10-bis(oxidanylidene)anthracene-2-carboxylic acid
    • 4,5-Dihydroxy-9,10-dioxo-9,10-dihydro-2-anthracenecarboxylic acid #
    • 9,10-Dihydro-4,5-dihydroxy-9,10-dioxo-2-anthracene carboxylic acid
    • 9,10-Dihydro-4,5-dihydroxy-9,10-dioxo-2-anthracenecarboxylic acid, 9CI
    • 9,10-Dihydro-4,5-dihydroxy-9,10-dioxo-2-anthracenecarboxylic Acid-13C6
    • 478-43-3

  • Applications

    Rhein is primarily used as a dye/pigment intermediate in anthraquinone chemistry, supporting production of pigments and inks; it is explored as a natural colorant for cosmetics and personal care formulations; it can function as a colorant/additive in coatings and plastics; it serves as a precursor or research starting material in pharmaceutical development and synthesis of anthraquinone derivatives; in analytical chemistry, Rhein is sometimes used as a reference material or tool for method development involving related compounds.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 0.35
    methanol 0.17
    isopropanol 0.37
    water 0.02
    ethyl acetate 0.46
    n-propanol 0.44
    acetone 0.18
    n-butanol 0.47
    acetonitrile 0.17
    DMF 12.64
    toluene 0.22
    isobutanol 0.25
    1,4-dioxane 2.63
    methyl acetate 0.68
    THF 6.92
    2-butanone 0.93
    n-pentanol 0.38
    sec-butanol 0.49
    n-hexane 0.0
    ethylene glycol 1.48
    NMP 17.16
    cyclohexane 0.01
    DMSO 10.94
    n-butyl acetate 1.1
    n-octanol 1.66
    chloroform 0.0
    n-propyl acetate 0.62
    acetic acid 0.36
    dichloromethane 0.01
    cyclohexanone 1.73
    propylene glycol 0.78
    isopropyl acetate 0.64
    DMAc 34.94
    2-ethoxyethanol 4.53
    isopentanol 0.61
    n-heptane 0.01
    ethyl formate 0.23
    1,2-dichloroethane 0.02
    n-hexanol 0.57
    2-methoxyethanol 9.82
    isobutyl acetate 0.25
    tetrachloromethane 0.01
    n-pentyl acetate 1.6
    transcutol 9.16
    n-heptanol 1.6
    ethylbenzene 0.25
    MIBK 0.7
    2-propoxyethanol 8.86
    tert-butanol 1.09
    MTBE 0.42
    2-butoxyethanol 6.9
    propionic acid 0.65
    o-xylene 0.42
    formic acid 1.12
    diethyl ether 0.23
    m-xylene 0.24
    p-xylene 0.23
    chlorobenzene 0.03
    dimethyl carbonate 1.68
    n-octane 0.01
    formamide 3.49
    cyclopentanone 2.87
    2-pentanone 0.59
    anisole 1.47
    cyclopentyl methyl ether 1.3
    gamma-butyrolactone 3.88
    1-methoxy-2-propanol 7.71
    pyridine 1.94
    3-pentanone 0.63
    furfural 3.16
    n-dodecane 0.03
    diethylene glycol 9.68
    diisopropyl ether 0.13
    tert-amyl alcohol 1.07
    acetylacetone 1.13
    n-hexadecane 0.04
    acetophenone 2.19
    methyl propionate 1.37
    isopentyl acetate 1.15
    trichloroethylene 0.04
    n-nonanol 2.06
    cyclohexanol 0.69
    benzyl alcohol 1.41
    2-ethylhexanol 0.61
    isooctanol 1.27
    dipropyl ether 0.8
    1,2-dichlorobenzene 0.08
    ethyl lactate 1.73
    propylene carbonate 1.03
    n-methylformamide 2.14
    2-pentanol 0.41
    n-pentane 0.0
    1-propoxy-2-propanol 5.96
    1-methoxy-2-propyl acetate 4.13
    2-(2-methoxypropoxy) propanol 7.04
    mesitylene 0.19
    ε-caprolactone 2.89
    p-cymene 0.37
    epichlorohydrin 2.0
    1,1,1-trichloroethane 0.01
    2-aminoethanol 1.55
    morpholine-4-carbaldehyde 15.56
    sulfolane 11.04
    2,2,4-trimethylpentane 0.01
    2-methyltetrahydrofuran 1.7
    n-hexyl acetate 2.21
    isooctane 0.01
    2-(2-butoxyethoxy)ethanol 8.55
    sec-butyl acetate 0.57
    tert-butyl acetate 1.47
    decalin 0.01
    glycerin 5.08
    diglyme 13.17
    acrylic acid 0.92
    isopropyl myristate 1.23
    n-butyric acid 0.56
    acetyl acetate 0.3
    di(2-ethylhexyl) phthalate 1.52
    ethyl propionate 1.09
    nitromethane 1.06
    1,2-diethoxyethane 2.33
    benzonitrile 0.66
    trioctyl phosphate 1.44
    1-bromopropane 0.02
    gamma-valerolactone 8.27
    n-decanol 1.47
    triethyl phosphate 1.77
    4-methyl-2-pentanol 0.4
    propionitrile 0.45
    vinylene carbonate 0.86
    1,1,2-trichlorotrifluoroethane 3.83
    DMS 2.26
    cumene 0.19
    2-octanol 1.05
    2-hexanone 0.72
    octyl acetate 1.78
    limonene 0.35
    1,2-dimethoxyethane 7.81
    ethyl orthosilicate 1.65
    tributyl phosphate 1.16
    diacetone alcohol 4.77
    N,N-dimethylaniline 1.68
    acrylonitrile 0.88
    aniline 0.99
    1,3-propanediol 2.56
    bromobenzene 0.02
    dibromomethane 0.0
    1,1,2,2-tetrachloroethane 0.07
    2-methyl-cyclohexyl acetate 1.5
    tetrabutyl urea 2.99
    diisobutyl methanol 0.58
    2-phenylethanol 2.18
    styrene 0.17
    dioctyl adipate 2.09
    dimethyl sulfate 5.25
    ethyl butyrate 1.13
    methyl lactate 3.88
    butyl lactate 2.22
    diethyl carbonate 1.04
    propanediol butyl ether 4.26
    triethyl orthoformate 1.84
    p-tert-butyltoluene 0.37
    methyl 4-tert-butylbenzoate 4.59
    morpholine 5.67
    tert-butylamine 0.28
    n-dodecanol 0.95
    dimethoxymethane 5.1
    ethylene carbonate 0.69
    cyrene 6.53
    2-ethoxyethyl acetate 2.85
    2-ethylhexyl acetate 0.98
    1,2,4-trichlorobenzene 0.22
    4-methylpyridine 1.47
    dibutyl ether 0.95
    2,6-dimethyl-4-heptanol 0.58
    DEF 3.91
    dimethyl isosorbide 9.94
    tetrachloroethylene 0.07
    eugenol 5.0
    triacetin 2.75
    span 80 4.06
    1,4-butanediol 0.75
    1,1-dichloroethane 0.01
    2-methyl-1-pentanol 0.53
    methyl formate 0.68
    2-methyl-1-butanol 0.55
    n-decane 0.04
    butyronitrile 0.28
    3,7-dimethyl-1-octanol 1.05
    1-chlorooctane 0.25
    1-chlorotetradecane 0.14
    n-nonane 0.03
    undecane 0.04
    tert-butylcyclohexane 0.01
    cyclooctane 0.01
    cyclopentanol 0.69
    tetrahydropyran 0.71
    tert-amyl methyl ether 0.85
    2,5,8-trioxanonane 12.31
    1-hexene 0.03
    2-isopropoxyethanol 2.67
    2,2,2-trifluoroethanol 0.43
    methyl butyrate 1.04

    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