Acetylene

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  • Identifiers

    CAS number
    74-86-2

    Molecular formula
    C2H2

    SMILES
    C#C

    Safety labels

    Flammable
    Flammable

    Compressed Gas
    Compressed Gas

  • Odor profile

    Fragrance
    Odorless 42.99%
    Pungent 30.9%
    Gassy 22.71%
    Sulfurous 18.73%
    Sharp 18.49%
    Alliaceous 17.59%
    Bitter 17.21%
    Burnt 17.12%
    Ethereal 16.57%
    Medicinal 16.28%

     

    Flavor
    Bitter 71.15%
    Odorless 26.32%
    Rotten 23.76%
    Sulfur 21.69%
    Formyl 21.61%
    Decomposing cabbage 20.32%
    Pungent 19.85%
    Egg 18.42%
    Mousy 18.07%
    Nitrile 18.03%

     

    Odor impact est.
    Low

    Odor threshold

    • Odor Threshold Low: 226.0 [ppm]. Odor Threshold High: 2584.0 [ppm]. Odor threshold from AIHA
    • Air: 620 ug/L; odor safety class B; B= 50-90% of distracted persons perceive warning of TLV.
    • detection: 240 mg/cu m; 1300-2750 mg/cu m
    • The odor threshold for acetylene is 657.2 mg/cu m.

  • Properties

    XLogP3-AA
    0.4

    pKa est.
    9.8 (weak base)

    Molecular weight
    26.04 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra fast

    Melting point expt.

    • -119 °F (Sublimes) (NIOSH, 2024)
    • -80.7 °C (triple point)
    • -119 °F (Sublimes)

    Boiling point

    • -119 °F at 760 mmHg (USCG, 1999)
    • -84.7 °C (sublimation point)
    • BP: -84 °C sublimes
    • Sublimes

    Flash point

    • -61.4 ˚C est.
    • 0 °F
    • Closed cup: -18.15 °C (-0.7 °F).
    • Flammable gas
    • NA (Gas)

    Solubility expt.

    • 2 % (NIOSH, 2024)
    • In water, 1200 mg/L at 25 °C
    • Soluble in water and many organic materials
    • Slightly soluble in ethanol, carbon disulfide; soluble in acetone, benzene, chloroform
    • One volume dissolves in 6 volumes of glacial acetic acid or alcohol. Soluble in ether, benzene. Acetone dissolves 25 volume at 15 °C, 760 mm Hg; acetone dissolves 300 vol at 12 atm
    • Moderately soluble in ethanol and acetic acid; very soluble in Me2CO; almost miscible in ether
    • Solubility in water, g/100ml at 20 °C: 0.12
    • 2%

  • Synonyms

    • ACETYLENE
    • Ethyne
    • Acetylen
    • Narcylen
    • Ethine
    • Vinylene
    • 74-86-2
    • Azetylen
    • Ethenylene
    • Ethin
    • C2H2
    • HSDB 166
    • Welding Gas
    • EINECS 200-816-9
    • UNII-OC7TV75O83
    • UN1001
    • [CH(CH)]
    • OC7TV75O83
    • DTXSID6026379
    • CHEBI:27518
    • CH#CH
    • HC#CH
    • ACETYLENE [MI]
    • ACETYLENE [HSDB]
    • ACETYLENE (D1)
    • EC 200-816-9
    • ACETYLENE (1,2-13C2)
    • UN 1001
    • (CH(CH))
    • Dicarbon
    • Diatomic carbon
    • Acetylene, dissolved
    • ACETILENE
    • NARCILENE
    • Acetylene (ACGIH)
    • Carbon (C2)
    • Acetylene [WHO-DD]
    • ACETILENE (Italian)
    • 60382-96-9
    • CHEMBL116336
    • DTXCID906379
    • DTXSID101027115
    • c0526
    • NS00001585
    • C01548
    • Acetylene, dissolved [UN1001] [Flammable gas]
    • Q133145
    • Q3591986
    • 12070-15-4
    • 200-816-9

  • Applications

    Acetylene (CAS 74-86-2) is a versatile industrial gas and chemical feedstock used as a flame fuel for welding and metal cutting with an oxyacetylene flame in construction and fabrication; as a key precursor for vinyl chloride monomer production (PVC) via acetylene hydrochlorination; as a feedstock for the synthesis of acetylene-derived intermediates and specialty polymers, including polyacetylene, and related ethynyl monomers in polymer and materials chemistry; and as a reactive building block in laboratory and pilot-scale synthesis of various alkynyl compounds. Its use is subject to local regulations and formulation limits.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 241.61
    methanol 270.29
    isopropanol 142.8
    water 0.8
    ethyl acetate 196.58
    n-propanol 187.7
    acetone 351.67
    n-butanol 165.16
    acetonitrile 342.73
    DMF 362.12
    toluene 51.05
    isobutanol 111.27
    1,4-dioxane 280.05
    methyl acetate 247.68
    THF 341.15
    2-butanone 229.22
    n-pentanol 85.47
    sec-butanol 116.21
    n-hexane 43.56
    ethylene glycol 92.05
    NMP 394.22
    cyclohexane 96.9
    DMSO 558.21
    n-butyl acetate 279.7
    n-octanol 56.94
    chloroform 473.11
    n-propyl acetate 141.8
    acetic acid 424.85
    dichloromethane 528.37
    cyclohexanone 366.8
    propylene glycol 69.23
    isopropyl acetate 78.56
    DMAc 165.95
    2-ethoxyethanol 109.77
    isopentanol 97.41
    n-heptane 69.7
    ethyl formate 205.01
    1,2-dichloroethane 343.78
    n-hexanol 137.46
    2-methoxyethanol 242.97
    isobutyl acetate 61.06
    tetrachloromethane 121.06
    n-pentyl acetate 93.25
    transcutol 327.9
    n-heptanol 56.53
    ethylbenzene 30.99
    MIBK 55.31
    2-propoxyethanol 151.75
    tert-butanol 119.0
    MTBE 79.07
    2-butoxyethanol 90.99
    propionic acid 286.02
    o-xylene 28.78
    formic acid 127.07
    diethyl ether 156.33
    m-xylene 25.85
    p-xylene 41.08
    chlorobenzene 165.1
    dimethyl carbonate 66.6
    n-octane 20.85
    formamide 237.49
    cyclopentanone 431.4
    2-pentanone 155.46
    anisole 73.01
    cyclopentyl methyl ether 142.9
    gamma-butyrolactone 551.21
    1-methoxy-2-propanol 135.1
    pyridine 330.32
    3-pentanone 123.79
    furfural 433.57
    n-dodecane 12.28
    diethylene glycol 118.26
    diisopropyl ether 31.45
    tert-amyl alcohol 88.29
    acetylacetone 149.7
    n-hexadecane 13.8
    acetophenone 83.48
    methyl propionate 147.19
    isopentyl acetate 149.44
    trichloroethylene 528.32
    n-nonanol 46.91
    cyclohexanol 144.85
    benzyl alcohol 65.86
    2-ethylhexanol 88.11
    isooctanol 40.84
    dipropyl ether 162.59
    1,2-dichlorobenzene 145.76
    ethyl lactate 51.71
    propylene carbonate 288.21
    n-methylformamide 310.15
    2-pentanol 88.85
    n-pentane 47.69
    1-propoxy-2-propanol 138.98
    1-methoxy-2-propyl acetate 115.48
    2-(2-methoxypropoxy) propanol 67.34
    mesitylene 16.63
    ε-caprolactone 287.24
    p-cymene 41.09
    epichlorohydrin 351.41
    1,1,1-trichloroethane 254.64
    2-aminoethanol 119.71
    morpholine-4-carbaldehyde 287.23
    sulfolane 533.99
    2,2,4-trimethylpentane 10.13
    2-methyltetrahydrofuran 250.99
    n-hexyl acetate 116.0
    isooctane 9.03
    2-(2-butoxyethoxy)ethanol 105.48
    sec-butyl acetate 57.19
    tert-butyl acetate 64.88
    decalin 18.96
    glycerin 96.7
    diglyme 213.25
    acrylic acid 274.22
    isopropyl myristate 43.86
    n-butyric acid 298.53
    acetyl acetate 127.05
    di(2-ethylhexyl) phthalate 34.76
    ethyl propionate 97.95
    nitromethane 593.83
    1,2-diethoxyethane 174.56
    benzonitrile 154.91
    trioctyl phosphate 33.69
    1-bromopropane 213.73
    gamma-valerolactone 403.51
    n-decanol 36.36
    triethyl phosphate 49.55
    4-methyl-2-pentanol 35.19
    propionitrile 235.93
    vinylene carbonate 265.31
    1,1,2-trichlorotrifluoroethane 301.65
    DMS 94.36
    cumene 20.06
    2-octanol 38.15
    2-hexanone 116.92
    octyl acetate 58.25
    limonene 73.8
    1,2-dimethoxyethane 200.74
    ethyl orthosilicate 47.75
    tributyl phosphate 45.33
    diacetone alcohol 81.73
    N,N-dimethylaniline 43.93
    acrylonitrile 328.56
    aniline 97.11
    1,3-propanediol 163.86
    bromobenzene 147.86
    dibromomethane 385.03
    1,1,2,2-tetrachloroethane 366.32
    2-methyl-cyclohexyl acetate 79.01
    tetrabutyl urea 63.82
    diisobutyl methanol 52.09
    2-phenylethanol 82.24
    styrene 52.11
    dioctyl adipate 66.2
    dimethyl sulfate 101.82
    ethyl butyrate 161.4
    methyl lactate 72.46
    butyl lactate 73.06
    diethyl carbonate 97.53
    propanediol butyl ether 76.24
    triethyl orthoformate 90.45
    p-tert-butyltoluene 34.38
    methyl 4-tert-butylbenzoate 56.74
    morpholine 308.68
    tert-butylamine 83.21
    n-dodecanol 30.01
    dimethoxymethane 148.53
    ethylene carbonate 212.7
    cyrene 65.07
    2-ethoxyethyl acetate 103.33
    2-ethylhexyl acetate 128.36
    1,2,4-trichlorobenzene 134.99
    4-methylpyridine 221.53
    dibutyl ether 110.87
    2,6-dimethyl-4-heptanol 52.09
    DEF 188.02
    dimethyl isosorbide 120.75
    tetrachloroethylene 296.94
    eugenol 64.36
    triacetin 88.81
    span 80 76.47
    1,4-butanediol 53.96
    1,1-dichloroethane 279.59
    2-methyl-1-pentanol 56.24
    methyl formate 220.1
    2-methyl-1-butanol 94.22
    n-decane 20.32
    butyronitrile 217.18
    3,7-dimethyl-1-octanol 54.36
    1-chlorooctane 57.08
    1-chlorotetradecane 22.88
    n-nonane 23.58
    undecane 15.2
    tert-butylcyclohexane 14.83
    cyclooctane 25.09
    cyclopentanol 183.1
    tetrahydropyran 291.51
    tert-amyl methyl ether 56.38
    2,5,8-trioxanonane 136.22
    1-hexene 90.95
    2-isopropoxyethanol 62.21
    2,2,2-trifluoroethanol 141.42
    methyl butyrate 159.45

    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