Hexamethylcyclotrisiloxane

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  • Identifiers

    CAS number
    541-05-9

    Molecular formula
    C6H18O3Si3

    SMILES
    C[Si]1(O[Si](O[Si](O1)(C)C)(C)C)C

    Safety labels

    Flammable
    Flammable

  • Odor profile

    Fragrance
    Odorless 64.86%
    Fruity 20.97%
    Green 18.79%
    Fresh 16.84%
    Ethereal 15.95%
    Alcoholic 15.58%
    Cooling 14.33%
    Earthy 13.86%
    Creamy 13.65%
    Meaty 13.62%

     

    Flavor
    Green 55.7%
    Earthy 50.4%
    Vegetable 39.74%
    Sulfurous 26.54%
    Sweet 25.16%
    Blackberry 24.66%
    Burnt 24.51%
    Potato 21.91%
    Herbal 21.62%
    Musty 20.9%

     

    Odor impact est.
    Low

  • Properties

    pKa est.
    7.81 (neutral)

    Molecular weight
    222.46 g/mol

    Flash point

    • 36.08 ˚C est.

  • Synonyms

    • HEXAMETHYLCYCLOTRISILOXANE
    • 541-05-9
    • Cyclotrisiloxane, hexamethyl-
    • Dimethylsiloxane cyclic trimer
    • SDK 10
    • DTXSID6027185
    • EPV75L8O0R
    • DC 246
    • LS 8120
    • DTXCID307185
    • RefChem:786203
    • 208-765-4
    • 2,2,4,4,6,6-Hexamethyl-1,3,5,2,4,6-trioxatrisilinane
    • C6H18O3Si3
    • MFCD00005943
    • S09550
    • CCRIS 1326
    • UNII-EPV75L8O0R
    • EINECS 208-765-4
    • 25084-99-5
    • AI3-62005
    • Simethicone Impurity 2
    • hexamethyl-1,3,5,2,4,6-trioxatrisilinane
    • Cyclotrisiloxane, 2,2,4,4,6,6-hexamethyl-
    • EC 208-765-4
    • SCHEMBL29235
    • Hexamethylcyclotrisiloxane, 98%
    • CHEMBL3182063
    • HTDJPCNNEPUOOQ-UHFFFAOYSA-
    • Hexamethylcyclotrisiloxane (NIST)
    • CHEBI:189167
    • CYCLOTRISILOXANE, HEXAMETHYL
    • Tox21_303233
    • CH7260
    • AKOS008901190
    • FH34246
    • NCGC00164098-01
    • NCGC00257091-01
    • AS-14775
    • CAS-541-05-9
    • H0725
    • NS00043163
    • Hexamethylcyclotrisiloxane, analytical standard
    • H11267
    • Q26840948
    • 2,2,4,4,6,6-Hexamethyl-1,3,5,2,4,6-trioxatrisilinane #
    • InChI=1/C6H18O3Si3/c1-10(2)7-11(3,4)9-12(5,6)8-10/h1-6H3
    • 541-05-9

  • Applications

    Hexamethylcyclotrisiloxane (CAS 541-05-9) is primarily used as a feedstock and intermediate in silicone chemistry, serving as a monomer/oligomer precursor for polydimethylsiloxane (PDMS) and related siloxane polymers through ring-opening or condensation steps. It is commonly employed as a processing aid or reactive diluent in silicone-based coatings, adhesives, and sealants to adjust viscosity and formulate performance. The compound also serves as an intermediate for higher-siloxane resins and specialty silicones used in electronics encapsulation, optical coatings, and dielectrics. In broader industrial manufacturing, HMCTS can be used to synthesize silicone resins and cyclic siloxane components that modify surface properties or compatibility within silicone systems. Subject to local regulations and formulation limits.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 201.32
    methanol 284.66
    isopropanol 124.96
    water 31.23
    ethyl acetate 242.5
    n-propanol 149.65
    acetone 305.29
    n-butanol 124.84
    acetonitrile 155.24
    DMF 464.21
    toluene 147.97
    isobutanol 83.38
    1,4-dioxane 382.33
    methyl acetate 203.59
    THF 800.58
    2-butanone 204.63
    n-pentanol 70.05
    sec-butanol 97.82
    n-hexane 37.12
    ethylene glycol 107.06
    NMP 595.86
    cyclohexane 73.05
    DMSO 473.15
    n-butyl acetate 141.4
    n-octanol 74.36
    chloroform 358.53
    n-propyl acetate 113.18
    acetic acid 230.11
    dichloromethane 348.53
    cyclohexanone 338.85
    propylene glycol 109.85
    isopropyl acetate 151.95
    DMAc 331.5
    2-ethoxyethanol 155.88
    isopentanol 71.52
    n-heptane 36.01
    ethyl formate 173.31
    1,2-dichloroethane 231.34
    n-hexanol 120.93
    2-methoxyethanol 384.68
    isobutyl acetate 68.11
    tetrachloromethane 101.35
    n-pentyl acetate 120.76
    transcutol 227.55
    n-heptanol 74.29
    ethylbenzene 51.57
    MIBK 113.02
    2-propoxyethanol 270.47
    tert-butanol 113.36
    MTBE 99.07
    2-butoxyethanol 131.4
    propionic acid 164.46
    o-xylene 88.1
    formic acid 164.16
    diethyl ether 223.87
    m-xylene 106.57
    p-xylene 57.69
    chlorobenzene 158.47
    dimethyl carbonate 159.1
    n-octane 19.19
    formamide 252.03
    cyclopentanone 507.5
    2-pentanone 208.78
    anisole 119.19
    cyclopentyl methyl ether 321.63
    gamma-butyrolactone 562.43
    1-methoxy-2-propanol 279.5
    pyridine 269.69
    3-pentanone 181.67
    furfural 432.38
    n-dodecane 15.32
    diethylene glycol 231.71
    diisopropyl ether 75.36
    tert-amyl alcohol 84.53
    acetylacetone 276.38
    n-hexadecane 17.36
    acetophenone 112.77
    methyl propionate 230.79
    isopentyl acetate 105.79
    trichloroethylene 335.25
    n-nonanol 69.93
    cyclohexanol 136.7
    benzyl alcohol 82.67
    2-ethylhexanol 69.91
    isooctanol 52.22
    dipropyl ether 132.36
    1,2-dichlorobenzene 142.99
    ethyl lactate 80.03
    propylene carbonate 271.08
    n-methylformamide 298.84
    2-pentanol 83.82
    n-pentane 46.19
    1-propoxy-2-propanol 170.55
    1-methoxy-2-propyl acetate 194.91
    2-(2-methoxypropoxy) propanol 104.3
    mesitylene 73.14
    ε-caprolactone 285.17
    p-cymene 51.86
    epichlorohydrin 410.33
    1,1,1-trichloroethane 207.3
    2-aminoethanol 146.34
    morpholine-4-carbaldehyde 429.57
    sulfolane 611.26
    2,2,4-trimethylpentane 15.74
    2-methyltetrahydrofuran 352.4
    n-hexyl acetate 144.54
    isooctane 14.26
    2-(2-butoxyethoxy)ethanol 139.42
    sec-butyl acetate 78.5
    tert-butyl acetate 154.17
    decalin 26.04
    glycerin 190.68
    diglyme 232.54
    acrylic acid 163.51
    isopropyl myristate 68.18
    n-butyric acid 194.6
    acetyl acetate 194.2
    di(2-ethylhexyl) phthalate 63.75
    ethyl propionate 133.46
    nitromethane 410.05
    1,2-diethoxyethane 122.91
    benzonitrile 99.62
    trioctyl phosphate 54.15
    1-bromopropane 146.6
    gamma-valerolactone 526.09
    n-decanol 53.59
    triethyl phosphate 75.18
    4-methyl-2-pentanol 46.82
    propionitrile 123.49
    vinylene carbonate 248.97
    1,1,2-trichlorotrifluoroethane 280.52
    DMS 148.56
    cumene 38.32
    2-octanol 58.09
    2-hexanone 100.66
    octyl acetate 87.22
    limonene 74.68
    1,2-dimethoxyethane 229.64
    ethyl orthosilicate 71.87
    tributyl phosphate 61.47
    diacetone alcohol 142.64
    N,N-dimethylaniline 89.86
    acrylonitrile 149.08
    aniline 156.66
    1,3-propanediol 177.89
    bromobenzene 161.86
    dibromomethane 245.07
    1,1,2,2-tetrachloroethane 283.4
    2-methyl-cyclohexyl acetate 99.76
    tetrabutyl urea 89.49
    diisobutyl methanol 42.42
    2-phenylethanol 120.89
    styrene 65.79
    dioctyl adipate 88.3
    dimethyl sulfate 251.73
    ethyl butyrate 118.58
    methyl lactate 158.69
    butyl lactate 93.12
    diethyl carbonate 83.25
    propanediol butyl ether 104.85
    triethyl orthoformate 96.22
    p-tert-butyltoluene 59.63
    methyl 4-tert-butylbenzoate 146.94
    morpholine 387.61
    tert-butylamine 79.39
    n-dodecanol 42.49
    dimethoxymethane 425.91
    ethylene carbonate 211.03
    cyrene 131.48
    2-ethoxyethyl acetate 158.12
    2-ethylhexyl acetate 98.83
    1,2,4-trichlorobenzene 168.45
    4-methylpyridine 232.18
    dibutyl ether 79.9
    2,6-dimethyl-4-heptanol 42.42
    DEF 231.58
    dimethyl isosorbide 231.7
    tetrachloroethylene 208.85
    eugenol 135.89
    triacetin 139.71
    span 80 112.5
    1,4-butanediol 58.55
    1,1-dichloroethane 185.11
    2-methyl-1-pentanol 46.21
    methyl formate 249.88
    2-methyl-1-butanol 74.05
    n-decane 24.0
    butyronitrile 115.66
    3,7-dimethyl-1-octanol 56.75
    1-chlorooctane 61.21
    1-chlorotetradecane 32.13
    n-nonane 23.11
    undecane 18.46
    tert-butylcyclohexane 22.12
    cyclooctane 36.76
    cyclopentanol 193.96
    tetrahydropyran 319.73
    tert-amyl methyl ether 102.19
    2,5,8-trioxanonane 175.95
    1-hexene 62.44
    2-isopropoxyethanol 94.63
    2,2,2-trifluoroethanol 134.71
    methyl butyrate 134.0

    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