2-Butyne

Overview IFRA Request a quote

  • Identifiers

    CAS number
    503-17-3

    Molecular formula
    C4H6

    SMILES
    CC#CC

    Safety labels

    Flammable
    Flammable

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Ethereal 50.95%
    Gassy 37.82%
    Pungent 35.2%
    Musty 31.35%
    Nutty 31.33%
    Green 29.6%
    Solvent 28.58%
    Sweet 28.52%
    Alcoholic 24.39%
    Sharp 24.12%

     

    Flavor
    Meaty 24.68%
    Fishy 23.96%
    Green 23.18%
    Citrus 23.03%
    Sulfurous 22.5%
    Woody 22.17%
    Bloody 20.17%
    Glue 19.98%
    Gasoline 19.84%
    Decomposing cabbage 19.62%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    1.5

    pKa est.
    8.24 (weak base)

    Molecular weight
    54.09 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra fast

    Boiling point est.
    29°C

    Flash point

    • -50.25 ˚C est.
    • -4 °F (NFPA, 2010)

  • Synonyms

    • 2-BUTYNE
    • But-2-yne
    • 503-17-3
    • Crotonylene
    • Dimethylacetylene
    • UN1144
    • dimethyl acetylene
    • UNII-LKE6D3018E
    • LKE6D3018E
    • 2-BUTINE
    • EINECS 207-962-2
    • CH3C.$.CCH3
    • DTXSID3060116
    • UN 1144
    • UN-1144
    • 4-butyne
    • 2-butyn
    • but-4-yne
    • MFCD00009275
    • 2-Butyne, 99%
    • CHEMBL119108
    • DTXCID2040812
    • DTXSID80231653
    • AKOS015841146
    • B0951
    • Crotonylene [UN1144] [Flammable liquid]
    • NS00020653
    • D88719
    • Q209336
    • 25684-85-9

  • Applications

    2-Butyne (CAS 503-17-3) is primarily used as an alkynyl building block and organic synthesis intermediate for making more complex compounds; it serves as a precursor to alkynyl derivatives and other structures containing a triple bond, supporting the manufacture of specialty chemicals and industrial materials. It can be used as a building block in polymers and plastics to introduce alkynyl functionality and enable surface modification in coatings. It is considered an intermediate for pharmaceutical synthesis to access pharmaceutical- and agrochemical-related intermediates. In research and development, it is used as a reagent in alkynylation reactions and related organic transformations, subject to regulations and safety conditions.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 1171.27
    methanol 1159.19
    isopropanol 1065.36
    water 7.99
    ethyl acetate 1541.36
    n-propanol 1051.82
    acetone 1150.74
    n-butanol 993.46
    acetonitrile 1655.64
    DMF 1385.32
    toluene 723.66
    isobutanol 752.37
    1,4-dioxane 1923.38
    methyl acetate 1503.77
    THF 1583.75
    2-butanone 1336.81
    n-pentanol 661.46
    sec-butanol 1134.65
    n-hexane 545.47
    ethylene glycol 280.12
    NMP 1121.42
    cyclohexane 457.24
    DMSO 748.25
    n-butyl acetate 636.7
    n-octanol 416.46
    chloroform 3642.37
    n-propyl acetate 625.92
    acetic acid 965.32
    dichloromethane 2663.98
    cyclohexanone 987.87
    propylene glycol 424.76
    isopropyl acetate 826.25
    DMAc 1388.28
    2-ethoxyethanol 836.21
    isopentanol 740.16
    n-heptane 458.3
    ethyl formate 663.28
    1,2-dichloroethane 1346.1
    n-hexanol 681.03
    2-methoxyethanol 1268.77
    isobutyl acetate 348.75
    tetrachloromethane 1257.45
    n-pentyl acetate 489.28
    transcutol 1438.79
    n-heptanol 421.6
    ethylbenzene 443.06
    MIBK 526.77
    2-propoxyethanol 846.13
    tert-butanol 1213.74
    MTBE 1213.14
    2-butoxyethanol 595.07
    propionic acid 1007.46
    o-xylene 489.0
    formic acid 328.62
    diethyl ether 1796.97
    m-xylene 450.43
    p-xylene 535.79
    chlorobenzene 778.04
    dimethyl carbonate 381.35
    n-octane 165.66
    formamide 607.0
    cyclopentanone 1057.22
    2-pentanone 1008.68
    anisole 793.58
    cyclopentyl methyl ether 948.6
    gamma-butyrolactone 1063.38
    1-methoxy-2-propanol 1062.61
    pyridine 1623.89
    3-pentanone 1008.16
    furfural 1134.89
    n-dodecane 90.0
    diethylene glycol 469.69
    diisopropyl ether 523.59
    tert-amyl alcohol 1210.66
    acetylacetone 848.89
    n-hexadecane 96.71
    acetophenone 569.66
    methyl propionate 1086.87
    isopentyl acetate 464.12
    trichloroethylene 2339.83
    n-nonanol 388.95
    cyclohexanol 691.88
    benzyl alcohol 527.27
    2-ethylhexanol 467.7
    isooctanol 326.69
    dipropyl ether 912.87
    1,2-dichlorobenzene 650.19
    ethyl lactate 294.31
    propylene carbonate 585.98
    n-methylformamide 881.11
    2-pentanol 867.18
    n-pentane 513.07
    1-propoxy-2-propanol 739.34
    1-methoxy-2-propyl acetate 536.2
    2-(2-methoxypropoxy) propanol 431.71
    mesitylene 285.05
    ε-caprolactone 936.9
    p-cymene 269.31
    epichlorohydrin 1445.96
    1,1,1-trichloroethane 2113.33
    2-aminoethanol 603.16
    morpholine-4-carbaldehyde 1217.69
    sulfolane 810.75
    2,2,4-trimethylpentane 214.82
    2-methyltetrahydrofuran 1562.32
    n-hexyl acetate 621.89
    isooctane 140.9
    2-(2-butoxyethoxy)ethanol 608.86
    sec-butyl acetate 487.97
    tert-butyl acetate 719.45
    decalin 213.57
    glycerin 443.04
    diglyme 1129.44
    acrylic acid 813.5
    isopropyl myristate 277.68
    n-butyric acid 1059.62
    acetyl acetate 805.89
    di(2-ethylhexyl) phthalate 180.12
    ethyl propionate 714.17
    nitromethane 1550.12
    1,2-diethoxyethane 884.46
    benzonitrile 670.61
    trioctyl phosphate 147.96
    1-bromopropane 1346.55
    gamma-valerolactone 1317.21
    n-decanol 283.12
    triethyl phosphate 254.15
    4-methyl-2-pentanol 432.96
    propionitrile 1372.97
    vinylene carbonate 592.23
    1,1,2-trichlorotrifluoroethane 1105.54
    DMS 432.26
    cumene 290.52
    2-octanol 326.71
    2-hexanone 668.13
    octyl acetate 362.76
    limonene 413.99
    1,2-dimethoxyethane 1310.18
    ethyl orthosilicate 276.12
    tributyl phosphate 168.5
    diacetone alcohol 681.58
    N,N-dimethylaniline 529.74
    acrylonitrile 1429.09
    aniline 820.45
    1,3-propanediol 679.35
    bromobenzene 798.27
    dibromomethane 2069.63
    1,1,2,2-tetrachloroethane 1910.39
    2-methyl-cyclohexyl acetate 370.83
    tetrabutyl urea 217.11
    diisobutyl methanol 306.85
    2-phenylethanol 478.37
    styrene 555.75
    dioctyl adipate 295.28
    dimethyl sulfate 469.51
    ethyl butyrate 637.25
    methyl lactate 424.16
    butyl lactate 308.3
    diethyl carbonate 391.95
    propanediol butyl ether 376.43
    triethyl orthoformate 427.28
    p-tert-butyltoluene 277.36
    methyl 4-tert-butylbenzoate 458.31
    morpholine 1998.08
    tert-butylamine 1004.46
    n-dodecanol 221.58
    dimethoxymethane 885.56
    ethylene carbonate 503.82
    cyrene 302.75
    2-ethoxyethyl acetate 592.45
    2-ethylhexyl acetate 415.06
    1,2,4-trichlorobenzene 782.84
    4-methylpyridine 1338.24
    dibutyl ether 618.68
    2,6-dimethyl-4-heptanol 306.85
    DEF 1261.61
    dimethyl isosorbide 546.33
    tetrachloroethylene 1545.13
    eugenol 396.8
    triacetin 491.28
    span 80 454.35
    1,4-butanediol 272.04
    1,1-dichloroethane 1919.06
    2-methyl-1-pentanol 567.3
    methyl formate 520.74
    2-methyl-1-butanol 790.67
    n-decane 169.4
    butyronitrile 1122.16
    3,7-dimethyl-1-octanol 398.64
    1-chlorooctane 413.03
    1-chlorotetradecane 156.85
    n-nonane 181.92
    undecane 116.13
    tert-butylcyclohexane 228.15
    cyclooctane 216.65
    cyclopentanol 716.81
    tetrahydropyran 1594.95
    tert-amyl methyl ether 1021.35
    2,5,8-trioxanonane 710.38
    1-hexene 909.93
    2-isopropoxyethanol 607.94
    2,2,2-trifluoroethanol 416.77
    methyl butyrate 776.17

    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