Octylphosphonic acid

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  • Identifiers

    CAS number
    4724-48-5

    Molecular formula
    C8H19O3P

    SMILES
    CCCCCCCCP(=O)(O)O

    Safety labels

    Corrosive
    Corrosive

    Irritant
    Irritant

    Health Hazard
    Health

  • Odor profile

    Fragrance
    Fatty 55.45%
    Waxy 47.06%
    Odorless 35.74%
    Cheesy 33.38%
    Oily 33.21%
    Dairy 31.95%
    Citrus 31.94%
    Milky 29.41%
    Green 29.4%
    Sour 28.21%

     

    Flavor
    Fatty 55.21%
    Waxy 44.55%
    Cheese 44.38%
    Sour 36.32%
    Rancid 34.91%
    Odorless 34.68%
    Sweat 31.68%
    Green 31.66%
    Oily 31.58%
    Mild 28.95%

     

    Odor impact est.
    Medium

  • Properties

    XLogP3-AA
    1.8

    pKa est.
    6.62 (neutral)

    Molecular weight
    194.21 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    346°C

    Flash point

    • 177.47 ˚C est.

  • Synonyms

    • Octylphosphonic acid
    • n-Octylphosphonic Acid
    • 4724-48-5
    • Phosphonic acid, octyl-
    • Phosphonic acid, P-octyl-
    • 95C2AW87BO
    • DTXSID3044679
    • DTXCID1024679
    • RefChem:167920
    • 225-218-5
    • 1-OCTYLPHOSPHONIC ACID
    • MFCD00015841
    • 1-Octanephosphonic acid
    • N-OCTYLPHOSPHONICACID
    • UNII-95C2AW87BO
    • EINECS 225-218-5
    • octanephosphonic acid
    • AI3-22858
    • EC 225-218-5
    • Octylphosphonic acid, 97%
    • SCHEMBL35167
    • N-Octylphosphonic acid mixture
    • n-Octylphosphonic Acid, 95%
    • SCHEMBL699777
    • SCHEMBL699778
    • CHEMBL3182594
    • NJGCRMAPOWGWMW-UHFFFAOYSA-N
    • MSK15581
    • Tox21_302242
    • AKOS015843131
    • GS-5553
    • NCGC00256096-01
    • SY020010
    • CAS-4724-48-5
    • DB-070783
    • CS-0152149
    • NS00007060
    • O0380
    • H10451
    • EN300-1697170
    • 724O485
    • F215647
    • Q27271779
    • F8889-2764
    • 4724-48-5

  • Applications

    Octylphosphonic acid, CAS 4724-48-5, is used as a metal chelating/sequestering agent in cleaning formulations and water treatment, and as a corrosion inhibitor and surface passivator for metal substrates in oil and gas and industrial equipment. It commonly serves as a surface modifier and coupling agent for metal oxides, forming self-assembled monolayers to improve coating adhesion and the interfacial bonding between inorganic and organic phases. With its phosphonic head and a hydrophobic octyl tail, it also behaves as a surfactant-like additive in paints, inks, and cleaners to enhance water resistance and dispersion. In polymer composites, it can act as a compatibilizer to improve bonding between inorganic fillers (such as silica) and polymers. These applications depend on local regulations and formulation constraints.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 740.66
    methanol 1374.08
    isopropanol 366.81
    water 15.8
    ethyl acetate 57.66
    n-propanol 464.79
    acetone 189.98
    n-butanol 308.02
    acetonitrile 34.58
    DMF 410.39
    toluene 31.46
    isobutanol 280.25
    1,4-dioxane 187.92
    methyl acetate 48.33
    THF 729.32
    2-butanone 93.99
    n-pentanol 297.66
    sec-butanol 244.3
    n-hexane 31.89
    ethylene glycol 494.01
    NMP 392.7
    cyclohexane 37.28
    DMSO 946.17
    n-butyl acetate 116.73
    n-octanol 115.91
    chloroform 50.89
    n-propyl acetate 93.25
    acetic acid 315.05
    dichloromethane 41.96
    cyclohexanone 267.13
    propylene glycol 590.83
    isopropyl acetate 66.74
    DMAc 215.24
    2-ethoxyethanol 498.68
    isopentanol 239.4
    n-heptane 23.49
    ethyl formate 69.06
    1,2-dichloroethane 55.77
    n-hexanol 358.8
    2-methoxyethanol 777.3
    isobutyl acetate 67.82
    tetrachloromethane 18.47
    n-pentyl acetate 87.95
    transcutol 501.78
    n-heptanol 189.94
    ethylbenzene 21.66
    MIBK 106.69
    2-propoxyethanol 533.99
    tert-butanol 479.94
    MTBE 104.73
    2-butoxyethanol 310.11
    propionic acid 254.92
    o-xylene 29.46
    formic acid 323.73
    diethyl ether 76.98
    m-xylene 39.97
    p-xylene 27.81
    chlorobenzene 29.15
    dimethyl carbonate 31.65
    n-octane 9.35
    formamide 340.65
    cyclopentanone 422.39
    2-pentanone 126.42
    anisole 52.8
    cyclopentyl methyl ether 268.0
    gamma-butyrolactone 340.44
    1-methoxy-2-propanol 548.41
    pyridine 96.7
    3-pentanone 63.11
    furfural 225.28
    n-dodecane 5.64
    diethylene glycol 466.6
    diisopropyl ether 39.93
    tert-amyl alcohol 315.5
    acetylacetone 126.45
    n-hexadecane 6.13
    acetophenone 69.2
    methyl propionate 65.82
    isopentyl acetate 106.98
    trichloroethylene 76.19
    n-nonanol 102.66
    cyclohexanol 293.01
    benzyl alcohol 106.13
    2-ethylhexanol 143.18
    isooctanol 140.61
    dipropyl ether 94.75
    1,2-dichlorobenzene 30.82
    ethyl lactate 84.38
    propylene carbonate 135.15
    n-methylformamide 287.66
    2-pentanol 188.43
    n-pentane 21.99
    1-propoxy-2-propanol 339.73
    1-methoxy-2-propyl acetate 127.38
    2-(2-methoxypropoxy) propanol 164.89
    mesitylene 32.93
    ε-caprolactone 213.01
    p-cymene 26.07
    epichlorohydrin 226.1
    1,1,1-trichloroethane 31.75
    2-aminoethanol 847.48
    morpholine-4-carbaldehyde 340.88
    sulfolane 587.81
    2,2,4-trimethylpentane 11.9
    2-methyltetrahydrofuran 321.79
    n-hexyl acetate 107.1
    isooctane 13.2
    2-(2-butoxyethoxy)ethanol 295.68
    sec-butyl acetate 58.97
    tert-butyl acetate 108.03
    decalin 14.76
    glycerin 707.94
    diglyme 346.11
    acrylic acid 192.99
    isopropyl myristate 42.02
    n-butyric acid 277.71
    acetyl acetate 35.22
    di(2-ethylhexyl) phthalate 56.15
    ethyl propionate 57.07
    nitromethane 177.69
    1,2-diethoxyethane 96.05
    benzonitrile 55.78
    trioctyl phosphate 56.59
    1-bromopropane 34.37
    gamma-valerolactone 412.21
    n-decanol 76.32
    triethyl phosphate 37.09
    4-methyl-2-pentanol 125.68
    propionitrile 50.73
    vinylene carbonate 88.85
    1,1,2-trichlorotrifluoroethane 265.33
    DMS 49.84
    cumene 22.41
    2-octanol 103.66
    2-hexanone 132.63
    octyl acetate 60.21
    limonene 43.79
    1,2-dimethoxyethane 331.11
    ethyl orthosilicate 42.13
    tributyl phosphate 50.42
    diacetone alcohol 249.9
    N,N-dimethylaniline 57.93
    acrylonitrile 59.63
    aniline 90.76
    1,3-propanediol 606.45
    bromobenzene 22.6
    dibromomethane 36.92
    1,1,2,2-tetrachloroethane 97.6
    2-methyl-cyclohexyl acetate 89.13
    tetrabutyl urea 73.88
    diisobutyl methanol 72.7
    2-phenylethanol 127.09
    styrene 22.14
    dioctyl adipate 61.14
    dimethyl sulfate 71.81
    ethyl butyrate 67.9
    methyl lactate 120.84
    butyl lactate 125.31
    diethyl carbonate 35.04
    propanediol butyl ether 277.79
    triethyl orthoformate 60.35
    p-tert-butyltoluene 30.46
    methyl 4-tert-butylbenzoate 99.71
    morpholine 355.19
    tert-butylamine 243.05
    n-dodecanol 54.89
    dimethoxymethane 220.41
    ethylene carbonate 84.84
    cyrene 164.48
    2-ethoxyethyl acetate 90.62
    2-ethylhexyl acetate 79.82
    1,2,4-trichlorobenzene 40.53
    4-methylpyridine 81.96
    dibutyl ether 48.31
    2,6-dimethyl-4-heptanol 72.7
    DEF 134.61
    dimethyl isosorbide 225.58
    tetrachloroethylene 95.36
    eugenol 120.93
    triacetin 84.45
    span 80 207.87
    1,4-butanediol 318.84
    1,1-dichloroethane 32.06
    2-methyl-1-pentanol 201.17
    methyl formate 128.81
    2-methyl-1-butanol 208.32
    n-decane 9.58
    butyronitrile 67.75
    3,7-dimethyl-1-octanol 101.68
    1-chlorooctane 32.57
    1-chlorotetradecane 13.29
    n-nonane 9.56
    undecane 6.98
    tert-butylcyclohexane 15.3
    cyclooctane 15.93
    cyclopentanol 462.71
    tetrahydropyran 224.97
    tert-amyl methyl ether 88.99
    2,5,8-trioxanonane 251.06
    1-hexene 66.96
    2-isopropoxyethanol 314.0
    2,2,2-trifluoroethanol 94.01
    methyl butyrate 89.42

    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