Carbon Monoxide

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  • Identifiers

    CAS number
    35907-63-2

    Molecular formula
    CO

    SMILES
    [C-]#[O+]

    Safety labels

    Flammable
    Flammable

    Compressed Gas
    Compressed Gas

    Acute Toxic
    Acute Toxic

    Health Hazard
    Health

  • Odor profile

    Fragrance
    Odorless 53.67%
    Pungent 20.6%
    Bitter 18.62%
    Sharp 16.18%
    Almond 15.72%
    Floral 15.17%
    Sweet 15.0%
    Fishy 14.09%
    Burnt 13.89%
    Phenolic 12.19%

     

    Flavor
    Bitter 76.65%
    Odorless 36.26%
    Rotten 22.26%
    Formyl 21.61%
    Sulfur 21.05%
    Decomposing cabbage 19.21%
    Mousy 18.79%
    Nitrile 18.74%
    Shrimp 17.55%
    Alkaline 17.01%

     

  • Properties

    XLogP3-AA
    0.7

    pKa est.
    5.58 (weak acid)

    Molecular weight
    28.01 g/mol

    Melting point expt.

    • -326 °F (USCG, 1999)
    • -337 °F (NIOSH, 2024)
    • -205.02 °C
    • -56.5 °C
    • -205 °C
    • -337 °F

    Boiling point

    • -312.7 °F at 760 mmHg (USCG, 1999)
    • -313 °F at 760 mmHg (NIOSH, 2024)
    • -191.5 undefined
    • -191.5 °C
    • -191 °C
    • -313 °F

    Flash point

    • 0.4 ˚C est.
    • Flammable gas
    • NA (Gas)

    Solubility expt.

    • 2 % (NIOSH, 2024)
    • 2 % (NIOSH, 2024)
    • Soluble in benzene
    • Freely absorbed by a concentrated solution of cuprous chloride in hydrochloric acid or ammonium hydroxide; Appreciably soluble in some organic solvents, such as ethyl acetate, chloroform, acetic acid; solubility in methanol and ethanol about 7 times as great as in water.
    • Sparingly soluble in water: 3.3 ml/100 ml at 0 °C, 2.3 ml/100 ml at 20 °C
    • 1.48 mg/mL at 25 °C
    • Solubility in water, ml/100ml at 20 °C: 2.3 (sparingly soluble)
    • 2%

  • Synonyms

    • 35907-63-2
    • CARBON MONOXIDE (13C; 18O)
    • carbon monoxide
    • carbon monooxide
    • Carbonic oxide
    • Carbon oxide (CO)
    • carbon(II) oxide
    • 630-08-0
    • Exhaust gas
    • Flue gas
    • monoxide
    • Kohlenmonoxid
    • Koolmonoxyde
    • Kohlenoxyd
    • Wegla tlenek
    • Oxyde de carbone
    • Carbone (oxyde de)
    • Carboneum oxygenisatum
    • Carbonio (ossido di)
    • HSDB 903
    • Carbon monoxide [USAN]
    • EINECS 211-128-3
    • UNII-7U1EE4V452
    • CHEBI:17245
    • 7U1EE4V452
    • Carbon monoxide, compressed
    • [CO]
    • DTXSID5027273
    • EC 211-128-3
    • Carbon monoxide (USAN)
    • (CO)
    • Kohlenoxyd [German]
    • Koolmonoxyde [Dutch]
    • CARBON MONOXIDE (MART.)
    • CARBON MONOXIDE [MART.]
    • Kohlenmonoxid [German]
    • Wegla tlenek [Polish]
    • CARBON MONOXIDE (EP MONOGRAPH)
    • CARBON MONOXIDE [EP MONOGRAPH]
    • Monoxide, Carbon
    • Oxyde de carbone [French]
    • C#O
    • Carbone (oxyde de) [French]
    • Carbonio (ossido di) [Italian]
    • NA9202
    • UN1016
    • Kohlenoxid
    • .carbon monoxide
    • Carbon monoxide 10% by volume or more
    • Carbon monoxide (DOT)
    • CARBON MONOXIDE [MI]
    • CARBON MONOXIDE [HSDB]
    • DTXCID407273
    • CARBON MONOXIDE [VANDF]
    • CHEMBL1231840
    • CARBON MONOXIDE [WHO-DD]
    • c0369
    • CARBONEUM OXYGENISATUM [HPUS]
    • DB11588
    • NS00075458
    • Q2025
    • C00237
    • D09706
    • Carbon monoxide, compressed [UN1016] [Poison gas]
    • Carbon monoxide, refrigerated liquid (cryogenic liquid)
    • Carbon monoxide, refrigerated liquid (cryogenic liquid) [NA9202] [Poison gas]
    • 211-128-3

  • Applications

    Chemical name: Carbon Monoxide (CAS 35907-63-2) is a colorless, toxic gas used primarily as a reducing agent in metallurgy; as a key component of syngas for industrial chemical manufacturing, enabling production of methanol, hydrocarbons via Fischer-Tropsch synthesis, and other carbon-based chemicals; as a reactive carbonyl source in carbonylation and hydroformylation processes to convert alkenes to aldehydes and related carboxyl compounds; in the Monsanto process for commercial acetic acid production from methanol and CO; and in laboratory and industrial metal carbonyl chemistry where metal carbonyl complexes serve as catalysts or precursors for various catalytic transformations.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 96.94
    methanol 168.66
    isopropanol 76.41
    water 29.56
    ethyl acetate 36.97
    n-propanol 64.15
    acetone 95.06
    n-butanol 49.17
    acetonitrile 77.62
    DMF 421.21
    toluene 9.57
    isobutanol 46.12
    1,4-dioxane 90.28
    methyl acetate 61.97
    THF 85.88
    2-butanone 54.51
    n-pentanol 34.1
    sec-butanol 53.91
    n-hexane 5.25
    ethylene glycol 85.98
    NMP 238.89
    cyclohexane 5.73
    DMSO 318.52
    n-butyl acetate 19.49
    n-octanol 23.54
    chloroform 29.61
    n-propyl acetate 21.86
    acetic acid 120.75
    dichloromethane 37.24
    cyclohexanone 46.67
    propylene glycol 54.53
    isopropyl acetate 20.46
    DMAc 286.13
    2-ethoxyethanol 68.41
    isopentanol 38.77
    n-heptane 5.24
    ethyl formate 35.91
    1,2-dichloroethane 31.9
    n-hexanol 26.11
    2-methoxyethanol 142.39
    isobutyl acetate 12.51
    tetrachloromethane 8.56
    n-pentyl acetate 18.17
    transcutol 121.01
    n-heptanol 18.44
    ethylbenzene 6.8
    MIBK 22.06
    2-propoxyethanol 55.21
    tert-butanol 89.97
    MTBE 47.7
    2-butoxyethanol 37.7
    propionic acid 72.31
    o-xylene 12.07
    formic acid 104.87
    diethyl ether 43.08
    m-xylene 8.82
    p-xylene 9.62
    chlorobenzene 13.57
    dimethyl carbonate 38.94
    n-octane 2.84
    formamide 135.96
    cyclopentanone 69.15
    2-pentanone 37.04
    anisole 22.9
    cyclopentyl methyl ether 37.0
    gamma-butyrolactone 87.38
    1-methoxy-2-propanol 87.78
    pyridine 50.02
    3-pentanone 32.21
    furfural 75.65
    n-dodecane 2.97
    diethylene glycol 69.55
    diisopropyl ether 13.44
    tert-amyl alcohol 64.1
    acetylacetone 39.77
    n-hexadecane 3.05
    acetophenone 22.48
    methyl propionate 46.61
    isopentyl acetate 17.2
    trichloroethylene 40.21
    n-nonanol 19.6
    cyclohexanol 35.83
    benzyl alcohol 23.11
    2-ethylhexanol 15.73
    isooctanol 14.35
    dipropyl ether 19.49
    1,2-dichlorobenzene 14.22
    ethyl lactate 20.96
    propylene carbonate 36.81
    n-methylformamide 157.96
    2-pentanol 34.28
    n-pentane 7.1
    1-propoxy-2-propanol 39.07
    1-methoxy-2-propyl acetate 25.51
    2-(2-methoxypropoxy) propanol 40.52
    mesitylene 7.69
    ε-caprolactone 42.55
    p-cymene 7.66
    epichlorohydrin 62.7
    1,1,1-trichloroethane 19.45
    2-aminoethanol 87.35
    morpholine-4-carbaldehyde 169.33
    sulfolane 117.33
    2,2,4-trimethylpentane 4.7
    2-methyltetrahydrofuran 57.95
    n-hexyl acetate 25.49
    isooctane 3.22
    2-(2-butoxyethoxy)ethanol 50.7
    sec-butyl acetate 13.66
    tert-butyl acetate 22.97
    decalin 3.5
    glycerin 86.43
    diglyme 91.68
    acrylic acid 79.61
    isopropyl myristate 12.28
    n-butyric acid 48.84
    acetyl acetate 22.15
    di(2-ethylhexyl) phthalate 13.6
    ethyl propionate 21.61
    nitromethane 166.24
    1,2-diethoxyethane 33.05
    benzonitrile 23.17
    trioctyl phosphate 11.88
    1-bromopropane 20.36
    gamma-valerolactone 90.03
    n-decanol 15.53
    triethyl phosphate 13.07
    4-methyl-2-pentanol 19.87
    propionitrile 45.2
    vinylene carbonate 35.65
    1,1,2-trichlorotrifluoroethane 70.59
    DMS 27.6
    cumene 6.65
    2-octanol 14.59
    2-hexanone 22.96
    octyl acetate 17.05
    limonene 11.56
    1,2-dimethoxyethane 98.44
    ethyl orthosilicate 12.43
    tributyl phosphate 12.63
    diacetone alcohol 39.29
    N,N-dimethylaniline 25.85
    acrylonitrile 63.65
    aniline 25.12
    1,3-propanediol 82.67
    bromobenzene 10.16
    dibromomethane 23.4
    1,1,2,2-tetrachloroethane 36.36
    2-methyl-cyclohexyl acetate 14.0
    tetrabutyl urea 20.95
    diisobutyl methanol 12.01
    2-phenylethanol 18.49
    styrene 9.13
    dioctyl adipate 17.96
    dimethyl sulfate 71.89
    ethyl butyrate 17.13
    methyl lactate 48.07
    butyl lactate 20.01
    diethyl carbonate 13.64
    propanediol butyl ether 42.57
    triethyl orthoformate 15.45
    p-tert-butyltoluene 7.68
    methyl 4-tert-butylbenzoate 27.75
    morpholine 107.99
    tert-butylamine 50.08
    n-dodecanol 12.65
    dimethoxymethane 117.97
    ethylene carbonate 29.69
    cyrene 34.41
    2-ethoxyethyl acetate 26.37
    2-ethylhexyl acetate 14.04
    1,2,4-trichlorobenzene 18.11
    4-methylpyridine 43.87
    dibutyl ether 18.06
    2,6-dimethyl-4-heptanol 12.01
    DEF 87.99
    dimethyl isosorbide 45.74
    tetrachloroethylene 27.81
    eugenol 30.49
    triacetin 28.76
    span 80 32.14
    1,4-butanediol 38.5
    1,1-dichloroethane 27.36
    2-methyl-1-pentanol 27.16
    methyl formate 100.85
    2-methyl-1-butanol 39.72
    n-decane 4.01
    butyronitrile 35.01
    3,7-dimethyl-1-octanol 18.66
    1-chlorooctane 10.58
    1-chlorotetradecane 5.7
    n-nonane 3.97
    undecane 3.36
    tert-butylcyclohexane 3.69
    cyclooctane 2.48
    cyclopentanol 49.62
    tetrahydropyran 50.85
    tert-amyl methyl ether 39.07
    2,5,8-trioxanonane 68.47
    1-hexene 12.27
    2-isopropoxyethanol 43.74
    2,2,2-trifluoroethanol 55.83
    methyl butyrate 29.49

    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