Tetramethoxysilane

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  • Identifiers

    CAS number
    681-84-5

    Molecular formula
    C4H12O4Si

    SMILES
    CO[Si](OC)(OC)OC

    Safety labels

    Flammable
    Flammable

    Corrosive
    Corrosive

    Acute Toxic
    Acute Toxic

    Irritant
    Irritant

    Health Hazard
    Health

  • Odor profile

    Fragrance
    Ethereal 53.99%
    Odorless 37.97%
    Fresh 34.62%
    Alcoholic 31.49%
    Fruity 31.46%
    Sweet 25.22%
    Sharp 23.31%
    Fermented 20.46%
    Earthy 19.79%
    Rummy 19.09%

     

    Flavor
    Green 57.47%
    Sweet 53.94%
    Fruity 42.79%
    Bitter 36.87%
    Ether 34.33%
    Sharp 31.5%
    Earthy 31.49%
    Alcoholic 30.39%
    Vegetable 28.93%
    Musty 25.84%

     

    Odor impact est.
    Medium

  • Properties

    pKa est.
    11.22 (strong base)

    Molecular weight
    152.22 g/mol

    Melting point expt.

    • 28 °F (NIOSH, 2024)
    • -1 °C
    • -2 °C
    • 28 °F

    Boiling point

    • 250 °F at 760 mmHg (NIOSH, 2024)
    • 121 °C
    • 250 °F

    Flash point

    • 23.84 ˚C est.
    • 205 °F (NIOSH, 2024)
    • 205 °F
    • 20 °C closed cup
    • 20 °C c.c.

    Solubility expt.

    • Soluble (NIOSH, 2024)
    • Very soluble in ethanol
    • SOL IN ORGANIC SOLVENTS
    • Not soluble in water
    • Solubility in water: none
    • Soluble

  • Synonyms

    • Tetramethoxysilane
    • Tetramethyl orthosilicate
    • TETRAMETHYL SILICATE
    • 681-84-5
    • Methyl silicate
    • TMOS
    • Methyl Silicate 39
    • Silane, tetramethoxy-
    • Methyl silicate 28
    • Tetramethylsilikat
    • Methyl silicate ((MeO)4Si)
    • TL 190
    • Methyl silicate ((CH3)4SiO4)
    • Silicic acid, methyl ester of ortho-
    • TSL 8114
    • Silicic acid (H4SiO4), tetramethyl ester
    • SIT 7510.0
    • MSP 150
    • DTXSID3027291
    • 19D35VPL66
    • NSC-67383
    • DTXCID207291
    • silicic acid tetramethyl ester
    • RefChem:897315
    • 211-656-4
    • Methyl orthosilicate
    • Silicic acid, tetramethyl ester
    • tetramethylorthosilicate
    • MFCD00008341
    • NSC 67383
    • Methyl silicate 51
    • Tetra-methyl orthosilicate
    • Tetramethylsilikat [Czech]
    • Methyl silicate 56
    • HSDB 5511
    • EINECS 211-656-4
    • UN2606
    • C4H12O4Si
    • UNII-19D35VPL66
    • AI3-11596
    • Methyl silicate, ((MeO)4Si)
    • Dynasil M
    • tetramethoxy silane
    • tetramethoxy-silane
    • tetramethylortho silicate
    • tetramethylortho-silicate
    • Si(OMe)4
    • EC 211-656-4
    • Si(OCH3)4
    • SCHEMBL17814
    • Tetramethyl orthosilicate, 98%
    • CHEMBL3183859
    • SCHEMBL11755779
    • TETRAMETHYL ESTER SILICATE
    • Tetramethyl orthosilicate, >=99%
    • TETRAMETHYL SILICATE [HSDB]
    • NSC67383
    • WLN: 1O-SI-O1&O1&O1
    • Tox21_200780
    • AKOS015902512
    • UN 2606
    • s15925
    • NCGC00248830-01
    • NCGC00258334-01
    • CAS-681-84-5
    • LS-13029
    • Methyl orthosilicate [UN2606] [Poison]
    • NS00041977
    • T0588
    • EN300-395310
    • A836042
    • Q377159
    • Tetramethyl orthosilicate, purum, >=98.0% (GC)
    • Tetramethyl orthosilicate, puriss., >=99.0% (GC)
    • F0001-1787
    • Tetramethyl orthosilicate, deposition grade, >=98%, >=99.9% trace metals basis
    • 681-84-5

  • Applications

    Tetramethoxysilane (CAS 681-84-5) is primarily used as a silica precursor in sol-gel technology to form silica coatings and thin films on glass, metal, and polymer substrates; it undergoes hydrolysis and condensation to yield siloxane networks that enable surface coatings with moisture resistance and chemical durability, and it also serves as a coupling agent to improve adhesion between inorganic surfaces and organic matrices in pastes and composites; as a precursor for silica-based resins and organosiloxane materials, it is used to prepare silsesquioxane and siloxane resins that enhance network rigidity and thermal stability; it is commonly employed to prepare silica sols and gels (xerogels and aerogels) for thermal insulation and catalyst supports in industrial applications.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 1013.93
    methanol 1900.91
    isopropanol 734.78
    water 485.39
    ethyl acetate 307.38
    n-propanol 741.27
    acetone 529.95
    n-butanol 649.29
    acetonitrile 505.16
    DMF 1052.82
    toluene 105.05
    isobutanol 473.08
    1,4-dioxane 653.68
    methyl acetate 383.19
    THF 848.65
    2-butanone 381.54
    n-pentanol 401.61
    sec-butanol 597.25
    n-hexane 52.99
    ethylene glycol 619.89
    NMP 663.46
    cyclohexane 96.79
    DMSO 1000.82
    n-butyl acetate 182.95
    n-octanol 209.55
    chloroform 1208.4
    n-propyl acetate 185.56
    acetic acid 1443.18
    dichloromethane 921.9
    cyclohexanone 386.89
    propylene glycol 555.17
    isopropyl acetate 202.22
    DMAc 692.84
    2-ethoxyethanol 836.33
    isopentanol 412.15
    n-heptane 71.9
    ethyl formate 422.26
    1,2-dichloroethane 446.99
    n-hexanol 283.38
    2-methoxyethanol 1547.97
    isobutyl acetate 107.2
    tetrachloromethane 329.73
    n-pentyl acetate 205.68
    transcutol 580.21
    n-heptanol 273.66
    ethylbenzene 56.55
    MIBK 165.82
    2-propoxyethanol 541.15
    tert-butanol 789.91
    MTBE 426.42
    2-butoxyethanol 509.35
    propionic acid 531.35
    o-xylene 92.84
    formic acid 1710.31
    diethyl ether 488.48
    m-xylene 77.37
    p-xylene 73.86
    chlorobenzene 145.57
    dimethyl carbonate 179.97
    n-octane 34.49
    formamide 1835.02
    cyclopentanone 463.53
    2-pentanone 303.37
    anisole 150.73
    cyclopentyl methyl ether 364.7
    gamma-butyrolactone 542.0
    1-methoxy-2-propanol 891.68
    pyridine 364.21
    3-pentanone 233.13
    furfural 573.55
    n-dodecane 18.91
    diethylene glycol 525.6
    diisopropyl ether 139.72
    tert-amyl alcohol 613.92
    acetylacetone 263.4
    n-hexadecane 19.89
    acetophenone 150.61
    methyl propionate 284.88
    isopentyl acetate 157.95
    trichloroethylene 752.33
    n-nonanol 182.15
    cyclohexanol 453.29
    benzyl alcohol 197.01
    2-ethylhexanol 160.85
    isooctanol 208.85
    dipropyl ether 208.8
    1,2-dichlorobenzene 154.01
    ethyl lactate 151.24
    propylene carbonate 294.88
    n-methylformamide 972.87
    2-pentanol 417.79
    n-pentane 104.56
    1-propoxy-2-propanol 365.36
    1-methoxy-2-propyl acetate 184.7
    2-(2-methoxypropoxy) propanol 184.22
    mesitylene 61.13
    ε-caprolactone 363.35
    p-cymene 68.95
    epichlorohydrin 638.79
    1,1,1-trichloroethane 411.16
    2-aminoethanol 870.47
    morpholine-4-carbaldehyde 647.41
    sulfolane 566.44
    2,2,4-trimethylpentane 54.76
    2-methyltetrahydrofuran 561.86
    n-hexyl acetate 205.58
    isooctane 34.77
    2-(2-butoxyethoxy)ethanol 298.25
    sec-butyl acetate 120.26
    tert-butyl acetate 227.41
    decalin 32.9
    glycerin 865.83
    diglyme 667.21
    acrylic acid 549.64
    isopropyl myristate 72.6
    n-butyric acid 626.79
    acetyl acetate 200.01
    di(2-ethylhexyl) phthalate 75.78
    ethyl propionate 151.82
    nitromethane 1328.05
    1,2-diethoxyethane 247.9
    benzonitrile 175.87
    trioctyl phosphate 76.63
    1-bromopropane 274.49
    gamma-valerolactone 651.47
    n-decanol 120.84
    triethyl phosphate 90.29
    4-methyl-2-pentanol 201.68
    propionitrile 344.65
    vinylene carbonate 309.48
    1,1,2-trichlorotrifluoroethane 747.43
    DMS 100.44
    cumene 49.62
    2-octanol 193.4
    2-hexanone 184.11
    octyl acetate 107.3
    limonene 109.68
    1,2-dimethoxyethane 735.74
    ethyl orthosilicate 103.21
    tributyl phosphate 67.94
    diacetone alcohol 296.76
    N,N-dimethylaniline 139.32
    acrylonitrile 395.57
    aniline 238.69
    1,3-propanediol 1004.12
    bromobenzene 120.46
    dibromomethane 590.68
    1,1,2,2-tetrachloroethane 723.73
    2-methyl-cyclohexyl acetate 120.17
    tetrabutyl urea 92.85
    diisobutyl methanol 120.83
    2-phenylethanol 170.3
    styrene 67.67
    dioctyl adipate 92.27
    dimethyl sulfate 244.69
    ethyl butyrate 159.36
    methyl lactate 253.18
    butyl lactate 178.63
    diethyl carbonate 104.77
    propanediol butyl ether 316.93
    triethyl orthoformate 141.68
    p-tert-butyltoluene 80.45
    methyl 4-tert-butylbenzoate 226.36
    morpholine 809.92
    tert-butylamine 543.21
    n-dodecanol 84.32
    dimethoxymethane 686.31
    ethylene carbonate 268.41
    cyrene 207.26
    2-ethoxyethyl acetate 220.93
    2-ethylhexyl acetate 121.41
    1,2,4-trichlorobenzene 182.04
    4-methylpyridine 299.66
    dibutyl ether 129.14
    2,6-dimethyl-4-heptanol 120.83
    DEF 438.96
    dimethyl isosorbide 230.47
    tetrachloroethylene 606.15
    eugenol 202.28
    triacetin 157.28
    span 80 193.83
    1,4-butanediol 436.02
    1,1-dichloroethane 431.22
    2-methyl-1-pentanol 268.52
    methyl formate 620.76
    2-methyl-1-butanol 424.54
    n-decane 36.46
    butyronitrile 367.91
    3,7-dimethyl-1-octanol 147.75
    1-chlorooctane 98.46
    1-chlorotetradecane 35.11
    n-nonane 37.48
    undecane 24.68
    tert-butylcyclohexane 34.43
    cyclooctane 45.93
    cyclopentanol 526.11
    tetrahydropyran 496.76
    tert-amyl methyl ether 340.3
    2,5,8-trioxanonane 327.15
    1-hexene 109.06
    2-isopropoxyethanol 435.46
    2,2,2-trifluoroethanol 759.46
    methyl butyrate 218.2

    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