Tetramethylammonium hydroxide

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  • Identifiers

    CAS number
    75-59-2

    Molecular formula
    C4H13NO

    SMILES
    C[N+](C)(C)C.[OH-]

    Safety labels

    Corrosive
    Corrosive

    Acute Toxic
    Acute Toxic

    Health Hazard
    Health

    Environmental Hazard
    Environmental

  • Odor profile

    Fragrance
    Camphoreous 43.6%
    Ethereal 40.58%
    Fermented 34.56%
    Solvent 32.81%
    Mint 32.04%
    Pungent 28.97%
    Fishy 27.76%
    Musty 27.74%
    Fresh 26.02%
    Alcoholic 24.22%

     

    Flavor
    Green 27.5%
    Sulfurous 24.16%
    Pungent 24.13%
    Fishy 22.58%
    Oily 20.9%
    Catty 20.04%
    Blackberry 19.95%
    Black currant 19.72%
    Yeasty 19.47%
    Cat-urine 19.47%

     

    Odor impact est.
    High

  • Properties

    pKa est.
    7.84 (neutral)

    Molecular weight
    91.15 g/mol

    Melting point expt.

    • 63 °C

    Flash point

    • -117.69 ˚C est.

  • Synonyms

    • TETRAMETHYLAMMONIUM HYDROXIDE
    • 75-59-2
    • TMAH
    • NMW-W
    • Hydroxyde de tetramethylammonium
    • Ammonium, tetramethyl-, hydroxide
    • NMD 3
    • Tetramethyl ammonium hydroxide
    • Methanaminium, N,N,N-trimethyl-, hydroxide
    • DTXSID3029108
    • 5GKP7317Q2
    • DTXCID309108
    • Methanaminium, N,N,N-trimethyl-, hydroxide (1:1)
    • RefChem:6296
    • 200-882-9
    • TMAOH
    • tetramethylazanium;hydroxide
    • MFCD00008280
    • tetramethylammoniumhydroxide
    • N,N,N-trimethylmethanaminium hydroxide
    • C4H13NO
    • Tetramethylammonium hydroxide solution
    • Tetramethylammonium Hydroxide (25% w/w solution in Water)
    • EINECS 200-882-9
    • UN1835
    • tetramethylazanium hydroxide
    • Hydroxyde de tetramethylammonium [French]
    • UNII-5GKP7317Q2
    • HSDB 8160
    • tetramethylammonium oxide
    • TMAH 10 % in water
    • tetramethylamonium hydroxide
    • EC 200-882-9
    • N,N,N-Trimethylmethanaminium hydroxide (1:1)
    • tetramethylammonium;hydroxide
    • SCHEMBL15477
    • SCHEMBL504668
    • CHEMBL3187523
    • Tox21_202572
    • AKOS015903652
    • Tetramethylammonium hydroxide, 25% aq
    • FT47018
    • CAS-75-59-2
    • NCGC00260121-01
    • TETRAMETHYLAMMONIUM HYDROXIDE [MI]
    • DB-050413
    • NS00078439
    • T0138
    • T0676
    • T1201
    • T1404
    • T1460
    • Tetramethylammonium hydroxide 25 wt% in Methanol
    • A838458
    • F492426
    • Q420868
    • Tetramethylammonium hydroxide, 10% aqueous solution
    • Tetramethylammonium hydroxide, 25% aqueous solution
    • Tetramethylammonium hydroxide, 25% w/w in methanol
    • Tetramethylammonium hydroxide [UN1835] [Corrosive]
    • European Pharmacopoeia Reagent Tetramethylammonium Hydroxide Solution 1L
    • 75-59-2

  • Applications

    Tetramethylammonium hydroxide (CAS 75-59-2) is a strong, water-soluble base widely used in electronics manufacturing as a developer for photoresists and as an etchant for silicon and related surfaces during wafer processing. It also serves as an industrial cleaning and stripping solution for wafers and equipment due to its effectiveness at removing organic residues under alkaline conditions. In chemical synthesis, it acts as a basic reagent and a source of tetramethylammonium cations, enabling certain organic reactions and the formation of quaternary ammonium salts. Its use is typically restricted to controlled formulations and handling, and is subject to local regulations and formulation limits.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 242.41
    methanol 313.45
    isopropanol 140.29
    water 33.55
    ethyl acetate 99.44
    n-propanol 203.71
    acetone 66.52
    n-butanol 156.64
    acetonitrile 86.73
    DMF 124.48
    toluene 39.31
    isobutanol 119.04
    1,4-dioxane 142.1
    methyl acetate 117.45
    THF 150.53
    2-butanone 87.17
    n-pentanol 61.28
    sec-butanol 149.64
    n-hexane 35.06
    ethylene glycol 206.75
    NMP 194.15
    cyclohexane 60.47
    DMSO 64.06
    n-butyl acetate 120.62
    n-octanol 82.24
    chloroform 340.91
    n-propyl acetate 51.65
    acetic acid 459.11
    dichloromethane 174.23
    cyclohexanone 111.45
    propylene glycol 237.62
    isopropyl acetate 51.98
    DMAc 146.95
    2-ethoxyethanol 107.45
    isopentanol 75.57
    n-heptane 82.55
    ethyl formate 87.01
    1,2-dichloroethane 77.05
    n-hexanol 182.2
    2-methoxyethanol 264.5
    isobutyl acetate 37.34
    tetrachloromethane 137.96
    n-pentyl acetate 57.74
    transcutol 219.15
    n-heptanol 106.87
    ethylbenzene 21.77
    MIBK 27.7
    2-propoxyethanol 231.97
    tert-butanol 133.39
    MTBE 76.89
    2-butoxyethanol 147.64
    propionic acid 306.32
    o-xylene 36.44
    formic acid 286.39
    diethyl ether 82.72
    m-xylene 27.87
    p-xylene 28.7
    chlorobenzene 58.13
    dimethyl carbonate 49.75
    n-octane 22.33
    formamide 158.44
    cyclopentanone 120.78
    2-pentanone 54.5
    anisole 48.36
    cyclopentyl methyl ether 93.14
    gamma-butyrolactone 168.07
    1-methoxy-2-propanol 165.58
    pyridine 121.53
    3-pentanone 68.74
    furfural 173.1
    n-dodecane 15.14
    diethylene glycol 197.47
    diisopropyl ether 26.49
    tert-amyl alcohol 143.63
    acetylacetone 48.55
    n-hexadecane 15.48
    acetophenone 44.93
    methyl propionate 100.1
    isopentyl acetate 89.45
    trichloroethylene 177.23
    n-nonanol 75.5
    cyclohexanol 147.47
    benzyl alcohol 53.79
    2-ethylhexanol 121.94
    isooctanol 66.26
    dipropyl ether 120.1
    1,2-dichlorobenzene 66.02
    ethyl lactate 66.93
    propylene carbonate 121.3
    n-methylformamide 132.28
    2-pentanol 92.92
    n-pentane 48.52
    1-propoxy-2-propanol 205.67
    1-methoxy-2-propyl acetate 106.59
    2-(2-methoxypropoxy) propanol 104.25
    mesitylene 19.63
    ε-caprolactone 131.93
    p-cymene 49.14
    epichlorohydrin 110.48
    1,1,1-trichloroethane 127.79
    2-aminoethanol 279.99
    morpholine-4-carbaldehyde 175.86
    sulfolane 152.98
    2,2,4-trimethylpentane 26.34
    2-methyltetrahydrofuran 130.2
    n-hexyl acetate 81.24
    isooctane 12.22
    2-(2-butoxyethoxy)ethanol 136.46
    sec-butyl acetate 39.07
    tert-butyl acetate 53.71
    decalin 19.82
    glycerin 290.8
    diglyme 184.46
    acrylic acid 306.69
    isopropyl myristate 39.67
    n-butyric acid 232.86
    acetyl acetate 81.33
    di(2-ethylhexyl) phthalate 47.54
    ethyl propionate 59.94
    nitromethane 199.56
    1,2-diethoxyethane 67.65
    benzonitrile 55.87
    trioctyl phosphate 39.7
    1-bromopropane 72.75
    gamma-valerolactone 158.46
    n-decanol 59.82
    triethyl phosphate 62.03
    4-methyl-2-pentanol 41.1
    propionitrile 101.86
    vinylene carbonate 121.49
    1,1,2-trichlorotrifluoroethane 269.89
    DMS 67.7
    cumene 19.87
    2-octanol 55.89
    2-hexanone 37.07
    octyl acetate 59.63
    limonene 78.73
    1,2-dimethoxyethane 94.1
    ethyl orthosilicate 64.67
    tributyl phosphate 48.59
    diacetone alcohol 74.43
    N,N-dimethylaniline 41.15
    acrylonitrile 112.85
    aniline 94.02
    1,3-propanediol 215.73
    bromobenzene 48.83
    dibromomethane 136.41
    1,1,2,2-tetrachloroethane 177.66
    2-methyl-cyclohexyl acetate 79.99
    tetrabutyl urea 50.46
    diisobutyl methanol 56.51
    2-phenylethanol 93.93
    styrene 26.76
    dioctyl adipate 55.37
    dimethyl sulfate 66.48
    ethyl butyrate 94.44
    methyl lactate 115.39
    butyl lactate 83.27
    diethyl carbonate 72.99
    propanediol butyl ether 122.73
    triethyl orthoformate 91.01
    p-tert-butyltoluene 53.63
    methyl 4-tert-butylbenzoate 83.28
    morpholine 191.17
    tert-butylamine 109.28
    n-dodecanol 48.72
    dimethoxymethane 76.21
    ethylene carbonate 97.22
    cyrene 74.9
    2-ethoxyethyl acetate 65.97
    2-ethylhexyl acetate 85.14
    1,2,4-trichlorobenzene 95.47
    4-methylpyridine 81.61
    dibutyl ether 59.82
    2,6-dimethyl-4-heptanol 56.51
    DEF 93.36
    dimethyl isosorbide 124.52
    tetrachloroethylene 169.45
    eugenol 85.37
    triacetin 92.31
    span 80 145.57
    1,4-butanediol 78.82
    1,1-dichloroethane 109.32
    2-methyl-1-pentanol 42.11
    methyl formate 91.74
    2-methyl-1-butanol 102.73
    n-decane 24.25
    butyronitrile 80.43
    3,7-dimethyl-1-octanol 64.25
    1-chlorooctane 50.38
    1-chlorotetradecane 24.74
    n-nonane 24.8
    undecane 18.46
    tert-butylcyclohexane 21.76
    cyclooctane 22.79
    cyclopentanol 162.42
    tetrahydropyran 134.37
    tert-amyl methyl ether 83.96
    2,5,8-trioxanonane 132.35
    1-hexene 51.45
    2-isopropoxyethanol 69.4
    2,2,2-trifluoroethanol 234.81
    methyl butyrate 67.92

    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