2-Ethenyl-2-butenal

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  • Identifiers

    CAS number
    20521-42-0

    Molecular formula
    C6H8O

    SMILES
    CC=C(C=C)C=O

    Safety labels

  • Odor profile

    Fragrance
    Pungent 69.74%
    Green 47.61%
    Spicy 45.73%
    Sharp 38.2%
    Nutty 37.85%
    Radish 36.98%
    Fruity 32.76%
    Ethereal 31.52%
    Alliaceous 31.07%
    Herbal 29.04%

     

    Flavor
    Sweet 38.7%
    Pungent 36.18%
    Nutty 34.32%
    Spicy 30.94%
    Cinnamon 27.03%
    Mustard 26.04%
    Cherry 25.92%
    Almond 23.6%
    Hazelnut 23.44%
    Red hots 22.39%

     

    Odor impact est.
    High

  • Properties

    XLogP3-AA
    1.3

    pKa est.
    7.03 (neutral)

    Molecular weight
    96.13 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Very fast

    Boiling point est.
    150°C

    Flash point

    • 30.9 ˚C est.

  • Synonyms

    • 20521-42-0
    • 2-ETHENYL-2-BUTENAL
    • RefChem:260218
    • 2-Vinyl-2-butenal
    • 2-ethenylbut-2-enal
    • 2-Butenal, 2-ethenyl-
    • SCHEMBL2039137
    • SCHEMBL2050665
    • XOBGIOGZLQNHMM-UHFFFAOYSA-N
    • DTXSID401315557
    • DB-251663
    • NS00051783
    • 20521-42-0

  • Applications

    2-Ethenyl-2-butenal (CAS 20521-42-0) is an α,β-unsaturated aldehyde that serves as a reactive intermediate and building block in industry. In fragrance applications, it can function as an odorant or as a precursor to other fragrance compounds. In the polymers and plastics sector, it may act as a monomer or as a copolymerizable/crosslinking component to tailor resin properties. In coatings, inks, and adhesives, it can be used as a reactive precursor to form bonds and to enhance film formation and adhesion. Its specific use depends on local regulations and formulation constraints.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 178.13
    methanol 214.59
    isopropanol 114.68
    water 1.06
    ethyl acetate 346.05
    n-propanol 165.14
    acetone 299.46
    n-butanol 155.37
    acetonitrile 345.29
    DMF 326.29
    toluene 122.18
    isobutanol 116.29
    1,4-dioxane 625.33
    methyl acetate 361.86
    THF 669.19
    2-butanone 342.21
    n-pentanol 137.25
    sec-butanol 123.77
    n-hexane 68.48
    ethylene glycol 35.42
    NMP 555.49
    cyclohexane 95.1
    DMSO 413.84
    n-butyl acetate 325.44
    n-octanol 85.32
    chloroform 611.98
    n-propyl acetate 254.78
    acetic acid 280.85
    dichloromethane 627.26
    cyclohexanone 520.01
    propylene glycol 31.96
    isopropyl acetate 167.84
    DMAc 209.49
    2-ethoxyethanol 189.79
    isopentanol 136.57
    n-heptane 46.1
    ethyl formate 192.31
    1,2-dichloroethane 448.62
    n-hexanol 174.99
    2-methoxyethanol 223.38
    isobutyl acetate 130.89
    tetrachloromethane 157.61
    n-pentyl acetate 157.84
    transcutol 910.96
    n-heptanol 78.8
    ethylbenzene 93.0
    MIBK 145.28
    2-propoxyethanol 240.04
    tert-butanol 174.12
    MTBE 180.8
    2-butoxyethanol 141.98
    propionic acid 244.8
    o-xylene 89.52
    formic acid 100.48
    diethyl ether 309.12
    m-xylene 84.77
    p-xylene 119.89
    chlorobenzene 271.1
    dimethyl carbonate 84.91
    n-octane 19.84
    formamide 162.03
    cyclopentanone 551.29
    2-pentanone 251.4
    anisole 201.54
    cyclopentyl methyl ether 313.48
    gamma-butyrolactone 742.82
    1-methoxy-2-propanol 158.63
    pyridine 436.5
    3-pentanone 219.66
    furfural 532.31
    n-dodecane 13.26
    diethylene glycol 151.23
    diisopropyl ether 88.27
    tert-amyl alcohol 157.39
    acetylacetone 259.97
    n-hexadecane 15.41
    acetophenone 186.88
    methyl propionate 237.31
    isopentyl acetate 245.78
    trichloroethylene 795.69
    n-nonanol 82.55
    cyclohexanol 189.37
    benzyl alcohol 133.66
    2-ethylhexanol 136.14
    isooctanol 70.28
    dipropyl ether 197.8
    1,2-dichlorobenzene 252.12
    ethyl lactate 85.21
    propylene carbonate 347.47
    n-methylformamide 228.25
    2-pentanol 116.62
    n-pentane 47.21
    1-propoxy-2-propanol 192.28
    1-methoxy-2-propyl acetate 233.28
    2-(2-methoxypropoxy) propanol 188.29
    mesitylene 66.97
    ε-caprolactone 498.88
    p-cymene 71.34
    epichlorohydrin 654.81
    1,1,1-trichloroethane 471.72
    2-aminoethanol 77.92
    morpholine-4-carbaldehyde 479.59
    sulfolane 682.63
    2,2,4-trimethylpentane 25.55
    2-methyltetrahydrofuran 554.69
    n-hexyl acetate 215.78
    isooctane 22.82
    2-(2-butoxyethoxy)ethanol 249.66
    sec-butyl acetate 156.29
    tert-butyl acetate 194.24
    decalin 44.43
    glycerin 54.19
    diglyme 455.61
    acrylic acid 211.28
    isopropyl myristate 93.84
    n-butyric acid 272.81
    acetyl acetate 202.2
    di(2-ethylhexyl) phthalate 80.24
    ethyl propionate 215.33
    nitromethane 526.56
    1,2-diethoxyethane 409.16
    benzonitrile 239.62
    trioctyl phosphate 58.45
    1-bromopropane 273.19
    gamma-valerolactone 601.72
    n-decanol 65.0
    triethyl phosphate 103.75
    4-methyl-2-pentanol 75.13
    propionitrile 257.32
    vinylene carbonate 303.52
    1,1,2-trichlorotrifluoroethane 282.59
    DMS 199.05
    cumene 67.67
    2-octanol 58.98
    2-hexanone 246.92
    octyl acetate 112.62
    limonene 119.81
    1,2-dimethoxyethane 380.17
    ethyl orthosilicate 101.09
    tributyl phosphate 80.97
    diacetone alcohol 180.24
    N,N-dimethylaniline 120.67
    acrylonitrile 331.3
    aniline 164.75
    1,3-propanediol 110.02
    bromobenzene 267.11
    dibromomethane 434.79
    1,1,2,2-tetrachloroethane 512.11
    2-methyl-cyclohexyl acetate 173.23
    tetrabutyl urea 102.42
    diisobutyl methanol 84.05
    2-phenylethanol 153.72
    styrene 120.45
    dioctyl adipate 132.28
    dimethyl sulfate 141.93
    ethyl butyrate 233.35
    methyl lactate 90.17
    butyl lactate 107.03
    diethyl carbonate 154.48
    propanediol butyl ether 116.74
    triethyl orthoformate 151.56
    p-tert-butyltoluene 67.03
    methyl 4-tert-butylbenzoate 146.29
    morpholine 579.33
    tert-butylamine 132.85
    n-dodecanol 51.92
    dimethoxymethane 202.02
    ethylene carbonate 247.6
    cyrene 158.87
    2-ethoxyethyl acetate 234.78
    2-ethylhexyl acetate 203.29
    1,2,4-trichlorobenzene 273.22
    4-methylpyridine 342.71
    dibutyl ether 173.92
    2,6-dimethyl-4-heptanol 84.05
    DEF 279.65
    dimethyl isosorbide 360.34
    tetrachloroethylene 385.41
    eugenol 144.72
    triacetin 194.12
    span 80 160.47
    1,4-butanediol 55.55
    1,1-dichloroethane 418.21
    2-methyl-1-pentanol 136.41
    methyl formate 178.02
    2-methyl-1-butanol 130.63
    n-decane 22.75
    butyronitrile 248.52
    3,7-dimethyl-1-octanol 104.78
    1-chlorooctane 87.21
    1-chlorotetradecane 35.72
    n-nonane 23.2
    undecane 16.92
    tert-butylcyclohexane 40.28
    cyclooctane 30.46
    cyclopentanol 205.26
    tetrahydropyran 572.95
    tert-amyl methyl ether 151.02
    2,5,8-trioxanonane 316.23
    1-hexene 163.06
    2-isopropoxyethanol 140.01
    2,2,2-trifluoroethanol 114.83
    methyl butyrate 271.07

    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