Isoprene

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  • Identifiers

    CAS number
    78-79-5

    Molecular formula
    C5H8

    SMILES
    CC(=C)C=C

    Safety labels

    Flammable
    Flammable

    Health Hazard
    Health

  • Odor profile

    Gassy 45.82%
    Pungent 43.78%
    Herbal 34.91%
    Green 28.49%
    Fruity 28.29%
    Sharp 27.64%
    Mint 26.73%
    Ethereal 26.05%
    Terpenic 23.54%
    Fresh 23.41%

    Scent© AI

  • Properties

    XLogP3-AA
    2.5

    Molecular weight
    68.12 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra fast

    Melting point expt.

    • -145.95 °C
    • The generally accepted crystal melting temperature of natural rubber is 30 °C.
    • -146 °C

    Boiling point

    • 34.067 °C
    • 34 °C

    Flash point est.
    -51.33 ˚C

    Flash point expt.

    • -65 °F (-54 °C) (Closed cup)

    Solubility expt.

    • In water, 642 mg/L at 25 °C
    • Practically insoluble in water
    • Miscible with ethanol, ethyl ether, acetone, benzene
    • Soluble in alcohol, ether, hydrocarbon solvents
    • Natural rubber is soluble in most aliphatic, aromatic, and chlorinated solvents, but its high molecular weight makes it difficult to dissolve.
    • Practically insol in water, alcohol, dil acids, or alkali; sol in abs ether, chloroform, most fixed or volatile oils, petroleum ether, carbon disulfide, oil of turpentine.
    • Raw rubber dissolves (or at least swells very strongly) in many organic liquids such as benzene, petroleum ether, crude petroleum, and carbon tetrachloride. In contrast, vulcanized rubber can only swell because the chemical cross-liking prevents dissolution.
    • Solubility in water, mg/l at 25 °C: 642 (very poor)

  • Synonyms

    • ISOPRENE
    • 78-79-5
    • 2-Methyl-1,3-butadiene
    • 2-Methylbuta-1,3-diene
    • Isopentadiene
    • 2-Methylbutadiene
    • 2-Methyldivinyl
    • 1,3-Butadiene, 2-methyl-
    • beta-Methylbivinyl
    • isopreno
    • isoterpene
    • Isopren
    • 3-Methyl-1,3-butadiene
    • CH2=C(CH3)CH=CH2
    • .beta.-Methylbivinyl
    • NSC 9237
    • Naturalrubber
    • CCRIS 6253
    • HSDB 620
    • EINECS 201-143-3
    • UNII-0A62964IBU
    • 9006-04-6
    • DTXSID2020761
    • NATURAL RUBBER
    • CHEBI:35194
    • 0A62964IBU
    • NSC-9237
    • DTXCID20761
    • Isoprene (Stabilized with TBC)
    • NSC9237
    • EC 201-143-3
    • ISOPRENE (IARC)
    • ISOPRENE [IARC]
    • Rubber, natural
    • UN1218
    • Caoutchouc
    • Elastomers
    • Ebonite
    • Heveaplus
    • Impervia
    • Rubber
    • Latex particles
    • Nafka
    • Natural latex
    • India rubber
    • Nafka kristalgom
    • Dynatex LA
    • Dynatex GTZ
    • Thiokol NVT
    • LATZ latex
    • 2-methyl-butadiene
    • Isoprene, inhibited
    • Harub 5LV
    • Heveacrumb SMR 5L
    • MFCD00008600
    • 2-methyl-1
    • Lorival R 25
    • Hartex 102HR
    • Cartex 600
    • Fultite FB 010K
    • Fultite FB 520
    • Hartex 103
    • Fultite FB 3001
    • Iotex C 60
    • Isoprene, >=99%
    • Kagetex FA 2005
    • ISOPRENE [HSDB]
    • E 218 (rubber)
    • Mitsuwa RC paper Cement
    • ISOPRENE [MI]
    • Defo 700
    • Elastic materials, rubber
    • UNII-2LQ0UUW8IN
    • Lotol L 9241
    • 2LQ0UUW8IN
    • Be Be Tex 1223
    • bmse000844
    • Defo 1000
    • ISNA 5
    • 2-methyl-buta-1,3-diene
    • AMA 7
    • CSV 1
    • Isoprene, analytical standard
    • Mar DR 1135
    • UN 1218 (Salt/Mix)
    • DRC 60
    • CHEMBL1566132
    • WLN: 1UY1&1U1
    • HSDB 6772
    • DTXSID60185761
    • GLN 200
    • GNL 150
    • Isoprene (1 mg/mL in Methanol)
    • JLX 105
    • JLX 113
    • KDP 150
    • CV 50
    • CV 60
    • IR 25
    • IR 68
    • EINECS 232-689-0
    • Tox21_200067
    • 5L-TP0203
    • CS 700
    • HC 106
    • AKOS000119971
    • CCG-266006
    • FB 3001
    • CAS-78-79-5
    • NCGC00091078-01
    • NCGC00091078-02
    • NCGC00257621-01
    • PD088096
    • I0160
    • NS00001388
    • EN300-19669
    • Q271943
    • Isoprene, inhibited [UN1218] [Flammable liquid]
    • InChI=1/C5H8/c1-4-5(2)3/h4H,1-2H2,3H
    • Z104474660
    • Isoprene, 99%, contains <1000 ppm p-tert-butylcatechol as inhibitor
    • 201-143-3
    • 26796-44-1
    • 9041-65-0

  • Applications

    Isoprene (CAS 78-79-5) is a key diene monomer for the rubber and petrochemical industries, primarily polymerized to cis-1,4-polyisoprene as a replacement or complement to natural rubber in tires, inner tubes, elastic bands, footwear soles, medical gloves, condoms, and other parts requiring resilience, abrasion resistance, and fatigue durability; it also forms copolymers such as SIS (styrene-isoprene-styrene) for pressure-sensitive adhesives, tapes, labels, sealants, and thermoplastic elastomers. A portion is copolymerized with isobutylene to make butyl rubber (IIR) with excellent gas-barrier and chemical resistance for tire innerliners, inner tubes, pharmaceutical stoppers, and vibration damping. C5 streams rich in isoprene feed tackifier production (polyterpene and C5 petroleum resins) for hot-melt adhesives and coatings. In fine chemicals, isoprene serves as a building block for isoprenoids, flavors, fragrances, and pharmaceuticals; its dimers and hydrogenated derivatives are explored as high-energy-density fuel components and gasoline additives; it is also used in atmospheric chemistry research and analytical instrument calibration.

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 282.59
    methanol 203.7
    isopropanol 221.75
    water 1.07
    ethyl acetate 371.7
    n-propanol 268.54
    acetone 144.28
    n-butanol 299.77
    acetonitrile 202.44
    DMF 150.65
    toluene 157.11
    isobutanol 167.34
    1,4-dioxane 333.73
    methyl acetate 233.12
    THF 395.48
    2-butanone 251.01
    n-pentanol 217.78
    sec-butanol 298.98
    n-hexane 180.85
    ethylene glycol 40.16
    NMP 153.06
    cyclohexane 101.0
    DMSO 105.99
    n-butyl acetate 348.94
    n-octanol 178.76
    chloroform 496.67
    n-propyl acetate 167.27
    acetic acid 132.39
    dichloromethane 313.41
    cyclohexanone 195.69
    propylene glycol 94.32
    isopropyl acetate 217.51
    DMAc 226.58
    2-ethoxyethanol 193.33
    isopentanol 226.98
    n-heptane 231.73
    ethyl formate 102.88
    1,2-dichloroethane 168.96
    n-hexanol 382.35
    2-methoxyethanol 232.27
    isobutyl acetate 106.71
    tetrachloromethane 139.27
    n-pentyl acetate 165.13
    transcutol 615.64
    n-heptanol 185.71
    ethylbenzene 108.27
    MIBK 145.32
    2-propoxyethanol 371.62
    tert-butanol 260.03
    MTBE 321.54
    2-butoxyethanol 210.19
    propionic acid 171.18
    o-xylene 114.47
    formic acid 37.26
    diethyl ether 426.98
    m-xylene 114.78
    p-xylene 104.39
    chlorobenzene 131.58
    dimethyl carbonate 62.22
    n-octane 71.73
    formamide 54.02
    cyclopentanone 198.29
    2-pentanone 228.74
    anisole 189.29
    cyclopentyl methyl ether 250.54
    gamma-butyrolactone 172.37
    1-methoxy-2-propanol 249.62
    pyridine 269.82
    3-pentanone 210.25
    furfural 160.41
    n-dodecane 41.1
    diethylene glycol 165.8
    diisopropyl ether 161.92
    tert-amyl alcohol 320.81
    acetylacetone 162.73
    n-hexadecane 42.8
    acetophenone 134.18
    methyl propionate 216.19
    isopentyl acetate 240.1
    trichloroethylene 277.0
    n-nonanol 168.01
    cyclohexanol 179.65
    benzyl alcohol 116.71
    2-ethylhexanol 289.42
    isooctanol 141.62
    dipropyl ether 449.55
    1,2-dichlorobenzene 107.11
    ethyl lactate 81.45
    propylene carbonate 123.47
    n-methylformamide 90.75
    2-pentanol 264.27
    n-pentane 154.02
    1-propoxy-2-propanol 389.71
    1-methoxy-2-propyl acetate 254.68
    2-(2-methoxypropoxy) propanol 215.32
    mesitylene 75.75
    ε-caprolactone 212.35
    p-cymene 112.23
    epichlorohydrin 228.6
    1,1,1-trichloroethane 250.45
    2-aminoethanol 108.55
    morpholine-4-carbaldehyde 205.02
    sulfolane 125.47
    2,2,4-trimethylpentane 72.1
    2-methyltetrahydrofuran 388.94
    n-hexyl acetate 212.19
    isooctane 51.85
    2-(2-butoxyethoxy)ethanol 276.14
    sec-butyl acetate 156.88
    tert-butyl acetate 208.35
    decalin 67.64
    glycerin 87.51
    diglyme 372.28
    acrylic acid 115.04
    isopropyl myristate 112.12
    n-butyric acid 259.24
    acetyl acetate 169.35
    di(2-ethylhexyl) phthalate 80.4
    ethyl propionate 196.31
    nitromethane 143.46
    1,2-diethoxyethane 386.02
    benzonitrile 125.62
    trioctyl phosphate 58.4
    1-bromopropane 258.01
    gamma-valerolactone 215.9
    n-decanol 128.57
    triethyl phosphate 98.31
    4-methyl-2-pentanol 151.59
    propionitrile 237.2
    vinylene carbonate 101.89
    1,1,2-trichlorotrifluoroethane 159.02
    DMS 111.44
    cumene 80.83
    2-octanol 130.6
    2-hexanone 185.45
    octyl acetate 141.09
    limonene 167.3
    1,2-dimethoxyethane 261.82
    ethyl orthosilicate 111.77
    tributyl phosphate 72.09
    diacetone alcohol 187.72
    N,N-dimethylaniline 131.35
    acrylonitrile 189.32
    aniline 168.24
    1,3-propanediol 143.09
    bromobenzene 134.29
    dibromomethane 284.24
    1,1,2,2-tetrachloroethane 266.07
    2-methyl-cyclohexyl acetate 161.06
    tetrabutyl urea 89.14
    diisobutyl methanol 154.99
    2-phenylethanol 176.22
    styrene 129.71
    dioctyl adipate 123.25
    dimethyl sulfate 64.4
    ethyl butyrate 290.58
    methyl lactate 89.25
    butyl lactate 111.17
    diethyl carbonate 154.97
    propanediol butyl ether 144.43
    triethyl orthoformate 205.41
    p-tert-butyltoluene 112.0
    methyl 4-tert-butylbenzoate 144.03
    morpholine 390.51
    tert-butylamine 221.21
    n-dodecanol 102.37
    dimethoxymethane 150.11
    ethylene carbonate 93.81
    cyrene 102.72
    2-ethoxyethyl acetate 189.53
    2-ethylhexyl acetate 219.42
    1,2,4-trichlorobenzene 131.91
    4-methylpyridine 238.14
    dibutyl ether 271.07
    2,6-dimethyl-4-heptanol 154.99
    DEF 246.94
    dimethyl isosorbide 235.68
    tetrachloroethylene 179.2
    eugenol 132.7
    triacetin 152.26
    span 80 201.64
    1,4-butanediol 62.24
    1,1-dichloroethane 230.73
    2-methyl-1-pentanol 213.44
    methyl formate 48.0
    2-methyl-1-butanol 234.73
    n-decane 72.65
    butyronitrile 242.08
    3,7-dimethyl-1-octanol 176.33
    1-chlorooctane 146.7
    1-chlorotetradecane 65.07
    n-nonane 77.81
    undecane 51.55
    tert-butylcyclohexane 74.05
    cyclooctane 61.79
    cyclopentanol 156.64
    tetrahydropyran 401.98
    tert-amyl methyl ether 315.25
    2,5,8-trioxanonane 270.66
    1-hexene 317.44
    2-isopropoxyethanol 175.74
    2,2,2-trifluoroethanol 44.76
    methyl butyrate 187.89

    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

Botanical

Name CAS Botanical Proportion
Agathosma apiculata Agathosma apiculata G.F.W. Mey, fam. Diosmeae (Rutaceae) 0.01%
Agathosma clavisepala Agathosma clavisepala R.A. Dyer, fam. Diosmeae (Rutaceae) 1.9%
Agathosma puberula Agathosma puberula Fourcade, fam. Diosmeae (Rutaceae) 1.8%