Isobutylene

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  • Identifiers

    CAS number
    115-11-7

    Molecular formula
    C4H8

    SMILES
    CC(=C)C

    Safety labels

    Flammable
    Flammable

    Compressed Gas
    Compressed Gas

  • Odor profile

    Fragrance
    Gassy 45.63%
    Camphoreous 43.09%
    Mint 40.25%
    Ethereal 37.76%
    Fresh 35.35%
    Pungent 34.43%
    Herbal 33.85%
    Terpenic 29.68%
    Musty 29.0%
    Citrus 27.69%

     

    Flavor
    Green 42.8%
    Pungent 41.58%
    Nutty 37.18%
    Citrus 37.13%
    Fruity 35.79%
    Ethereal 34.69%
    Earthy 30.34%
    Sweet 28.75%
    Woody 28.64%
    Solvent 28.13%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    2.1

    pKa est.
    11.21 (strong base)

    Molecular weight
    56.11 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra fast

    Melting point expt.

    • -220.5 °F (NTP, 1992)
    • -140.7 °C
    • -140.3 °C

    Boiling point

    • 19.6 °F at 760 mmHg (NTP, 1992)
    • -7.0 °C
    • -6.9 °C

    Flash point

    • -74.16 ˚C est.
    • -105 °F (NTP, 1992)
    • -76 °C
    • -80 °C (-112 °F) - closed cup
    • -105 °F (-76 °C)
    • -76.1 °C c.c.

    Solubility expt.

    • Insoluble (NTP, 1992)
    • In water, 263 mg/L at 25 °C
    • Very soluble in ethanol and ether; soluble in benzene, sulfuric acid
    • Soluble in organic solvents
    • Solubility in water, g/100ml at 20 °C: 0.03

  • Synonyms

    • ISOBUTYLENE
    • Isobutene
    • 2-methylprop-1-ene
    • 2-Methylpropene
    • 115-11-7
    • 2-Methyl-1-propene
    • 2-Methylpropylene
    • 1,1-Dimethylethylene
    • 1-Propene, 2-methyl-
    • Isopropylidenemethylene
    • Methylpropene
    • gamma-Butylene
    • Propene, 2-methyl-
    • 1,1-Dimethylethene
    • iso-butene
    • i-butene
    • unsym. dimethylethylene
    • CCRIS 2281
    • HSDB 613
    • UNII-QA2LMR467H
    • EINECS 204-066-3
    • QA2LMR467H
    • 2-METHYL-D3-PROPENE
    • DTXSID9020748
    • CHEBI:43907
    • Isobutene (ca. 9% in Hexane)
    • Isobutene (ca. 6% in Toluene)
    • EC 204-066-3
    • MFCD00008898
    • Isobutene (ca. 8% in Dichloromethane)
    • Isobutene (ca. 15% in Tetrahydrofuran)
    • Isobutene (ca. 10% in Isopropyl Ether)
    • 2-METHYL-D3-PROPENE-3,3,3-D3
    • 42278-27-3
    • sym-Dimethylethylene
    • 2-methyl-2-propene
    • UN1055
    • isobutylene, various grades
    • iso-butylene
    • Isobutene trimer
    • 2-Methylpropyline
    • .gamma.-Butylene
    • 2-methyl-l-propene
    • 2-methyl-2 propene
    • iso-C4H8
    • 2-Methylpropene, 99%
    • ISOBUTYLENE [MI]
    • ISOBUTYLENE [HSDB]
    • Unsymmetrical dimethylethylene
    • ISOBUTYLENE [WHO-DD]
    • DTXCID90748
    • Propene, 2-methyl-, tetramer
    • 1,3-Propanediyl, 2-methylene-
    • DTXSID50164803
    • DTXSID601307041
    • 2-Methylpropene, purum, >=99.5%
    • AKOS000121111
    • UN 1055
    • FP168349
    • I0091
    • I0909
    • I0910
    • I0911
    • I1082
    • I1083
    • NS00007976
    • InChI=1/C4H8/c1-4(2)3/h1H2,2-3H
    • A803373
    • Q776976
    • 13001-05-3
    • 204-066-3

  • Applications

    Isobutylene (CAS 115-11-7) is a primary feedstock for polyisobutylene polymers, providing viscosity-modifying polymers for lubricants and tackifiers for adhesives and sealants; it is also a monomer for specialty polymers and functional PIBs used in coatings, inks, and packaging. It can be converted to tert-butanol and to MTBE (methyl tert-butyl ether), with MTBE historically used as a gasoline oxygenate solvent and tert-butanol as an intermediate in chemical syntheses. Isobutylene is also a precursor for tert-butyl esters (e.g., tert-butyl acrylate/methacrylate) used in polymer and coating formulations. It serves as a versatile intermediate in the synthesis of various specialty polymers and materials for industrial applications, subject to local regulations and formulation limits.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 133.62
    methanol 128.49
    isopropanol 134.1
    water 1.74
    ethyl acetate 133.55
    n-propanol 138.69
    acetone 116.93
    n-butanol 164.86
    acetonitrile 80.1
    DMF 131.47
    toluene 85.49
    isobutanol 119.09
    1,4-dioxane 193.82
    methyl acetate 115.29
    THF 285.61
    2-butanone 139.68
    n-pentanol 109.58
    sec-butanol 167.18
    n-hexane 206.61
    ethylene glycol 54.55
    NMP 213.26
    cyclohexane 174.02
    DMSO 82.8
    n-butyl acetate 212.58
    n-octanol 174.3
    chloroform 229.46
    n-propyl acetate 90.77
    acetic acid 117.4
    dichloromethane 134.54
    cyclohexanone 186.09
    propylene glycol 99.49
    isopropyl acetate 108.59
    DMAc 186.62
    2-ethoxyethanol 108.05
    isopentanol 142.65
    n-heptane 329.53
    ethyl formate 56.72
    1,2-dichloroethane 87.47
    n-hexanol 328.78
    2-methoxyethanol 162.05
    isobutyl acetate 80.83
    tetrachloromethane 93.93
    n-pentyl acetate 106.61
    transcutol 325.64
    n-heptanol 169.43
    ethylbenzene 67.95
    MIBK 100.55
    2-propoxyethanol 295.88
    tert-butanol 212.47
    MTBE 216.62
    2-butoxyethanol 167.84
    propionic acid 118.71
    o-xylene 82.59
    formic acid 35.42
    diethyl ether 180.87
    m-xylene 80.73
    p-xylene 80.05
    chlorobenzene 80.16
    dimethyl carbonate 51.4
    n-octane 96.3
    formamide 31.71
    cyclopentanone 191.29
    2-pentanone 130.46
    anisole 108.89
    cyclopentyl methyl ether 209.26
    gamma-butyrolactone 146.4
    1-methoxy-2-propanol 169.71
    pyridine 119.26
    3-pentanone 136.47
    furfural 123.09
    n-dodecane 70.21
    diethylene glycol 149.83
    diisopropyl ether 114.63
    tert-amyl alcohol 243.21
    acetylacetone 106.65
    n-hexadecane 72.45
    acetophenone 92.15
    methyl propionate 110.55
    isopentyl acetate 193.15
    trichloroethylene 142.58
    n-nonanol 168.41
    cyclohexanol 177.42
    benzyl alcohol 70.03
    2-ethylhexanol 284.83
    isooctanol 132.6
    dipropyl ether 326.15
    1,2-dichlorobenzene 78.0
    ethyl lactate 72.74
    propylene carbonate 106.5
    n-methylformamide 59.27
    2-pentanol 161.89
    n-pentane 156.51
    1-propoxy-2-propanol 334.49
    1-methoxy-2-propyl acetate 189.78
    2-(2-methoxypropoxy) propanol 211.99
    mesitylene 65.34
    ε-caprolactone 161.95
    p-cymene 110.44
    epichlorohydrin 131.13
    1,1,1-trichloroethane 155.86
    2-aminoethanol 93.94
    morpholine-4-carbaldehyde 171.69
    sulfolane 167.97
    2,2,4-trimethylpentane 89.45
    2-methyltetrahydrofuran 254.43
    n-hexyl acetate 180.02
    isooctane 71.44
    2-(2-butoxyethoxy)ethanol 233.84
    sec-butyl acetate 93.02
    tert-butyl acetate 146.24
    decalin 85.12
    glycerin 106.82
    diglyme 277.7
    acrylic acid 94.41
    isopropyl myristate 126.86
    n-butyric acid 150.11
    acetyl acetate 91.05
    di(2-ethylhexyl) phthalate 95.84
    ethyl propionate 105.87
    nitromethane 95.06
    1,2-diethoxyethane 171.37
    benzonitrile 70.82
    trioctyl phosphate 84.14
    1-bromopropane 125.21
    gamma-valerolactone 175.9
    n-decanol 143.06
    triethyl phosphate 99.44
    4-methyl-2-pentanol 115.73
    propionitrile 93.44
    vinylene carbonate 77.67
    1,1,2-trichlorotrifluoroethane 145.5
    DMS 104.87
    cumene 63.26
    2-octanol 119.05
    2-hexanone 110.04
    octyl acetate 155.38
    limonene 198.4
    1,2-dimethoxyethane 169.18
    ethyl orthosilicate 109.7
    tributyl phosphate 96.27
    diacetone alcohol 162.48
    N,N-dimethylaniline 101.04
    acrylonitrile 77.58
    aniline 98.0
    1,3-propanediol 103.07
    bromobenzene 78.27
    dibromomethane 136.28
    1,1,2,2-tetrachloroethane 161.57
    2-methyl-cyclohexyl acetate 178.63
    tetrabutyl urea 122.02
    diisobutyl methanol 163.07
    2-phenylethanol 130.43
    styrene 72.09
    dioctyl adipate 137.69
    dimethyl sulfate 59.12
    ethyl butyrate 172.2
    methyl lactate 85.72
    butyl lactate 109.42
    diethyl carbonate 115.84
    propanediol butyl ether 151.58
    triethyl orthoformate 156.85
    p-tert-butyltoluene 119.84
    methyl 4-tert-butylbenzoate 156.52
    morpholine 207.5
    tert-butylamine 197.79
    n-dodecanol 126.85
    dimethoxymethane 106.59
    ethylene carbonate 75.44
    cyrene 115.44
    2-ethoxyethyl acetate 103.92
    2-ethylhexyl acetate 180.09
    1,2,4-trichlorobenzene 100.92
    4-methylpyridine 117.05
    dibutyl ether 207.75
    2,6-dimethyl-4-heptanol 163.07
    DEF 147.89
    dimethyl isosorbide 246.68
    tetrachloroethylene 123.37
    eugenol 130.91
    triacetin 152.69
    span 80 253.88
    1,4-butanediol 54.27
    1,1-dichloroethane 125.59
    2-methyl-1-pentanol 110.03
    methyl formate 43.03
    2-methyl-1-butanol 148.24
    n-decane 104.71
    butyronitrile 102.24
    3,7-dimethyl-1-octanol 187.12
    1-chlorooctane 142.48
    1-chlorotetradecane 85.2
    n-nonane 111.53
    undecane 83.02
    tert-butylcyclohexane 95.64
    cyclooctane 108.06
    cyclopentanol 166.3
    tetrahydropyran 238.87
    tert-amyl methyl ether 215.05
    2,5,8-trioxanonane 245.21
    1-hexene 196.1
    2-isopropoxyethanol 105.31
    2,2,2-trifluoroethanol 49.1
    methyl butyrate 110.17

    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