Pyrophosphorous acid

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  • Identifiers

    CAS number
    13445-56-2

    Molecular formula
    H4O5P2

    SMILES
    OP(O)OP(O)O

    Safety labels

  • Odor profile

    Fragrance
    Odorless 58.48%
    Sweet 26.21%
    Alcoholic 19.37%
    Fresh 19.09%
    Green 17.89%
    Clean 16.92%
    Fishy 15.74%
    Balsamic 14.18%
    Oily 13.46%
    Ethereal 13.45%

     

    Flavor
    Odorless 71.21%
    Mild 26.51%
    Sweet-like 24.97%
    Sweet 24.74%
    Bland 22.22%
    Bitter 21.67%
    Very slight 20.86%
    Yeast 20.62%
    Formyl 19.97%
    Rotten 19.51%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    -2.1

    pKa est.
    5.57 (weak acid)

    Molecular weight
    145.98 g/mol

    Flash point

    • 190.0 ˚C est.

  • Synonyms

    • Pyrophosphorous acid
    • Diphosphorous acid
    • W4W7JY3ELM
    • 13445-56-2
    • DTXSID00331169
    • RefChem:1097567
    • DTXCID00282263
    • UNII-W4W7JY3ELM
    • SCHEMBL19090
    • NS00112949
    • Q27292300
    • 13445-56-2

  • Applications

    Pyrophosphorous acid (CAS 13445-56-2) is used mainly as a reducing agent and as a phosphorus-containing building block in organophosphorus chemistry. It serves as a precursor for phosphite esters and related organophosphorus compounds, which find application as polymer stabilizers and antioxidants. It is employed as a reagent in the synthesis of phosphorus-containing additives for coatings and inks and may function as a ligand or reagent in coordination chemistry and catalysis. In industrial formulations, it can be used to produce phosphorus-containing flame retardants or corrosion inhibitors, with use governed by formulation needs and local regulations.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 117.97
    methanol 189.92
    isopropanol 100.37
    water 216.73
    ethyl acetate 38.8
    n-propanol 71.21
    acetone 140.92
    n-butanol 54.73
    acetonitrile 39.13
    DMF 457.73
    toluene 9.15
    isobutanol 41.08
    1,4-dioxane 87.89
    methyl acetate 40.27
    THF 276.5
    2-butanone 57.02
    n-pentanol 34.67
    sec-butanol 50.98
    n-hexane 4.44
    ethylene glycol 140.28
    NMP 240.25
    cyclohexane 4.55
    DMSO 566.88
    n-butyl acetate 27.38
    n-octanol 22.18
    chloroform 10.54
    n-propyl acetate 25.96
    acetic acid 89.4
    dichloromethane 14.04
    cyclohexanone 52.9
    propylene glycol 128.13
    isopropyl acetate 35.28
    DMAc 235.65
    2-ethoxyethanol 124.69
    isopentanol 36.27
    n-heptane 5.6
    ethyl formate 42.29
    1,2-dichloroethane 19.79
    n-hexanol 34.34
    2-methoxyethanol 274.04
    isobutyl acetate 13.29
    tetrachloromethane 4.58
    n-pentyl acetate 22.55
    transcutol 134.96
    n-heptanol 22.67
    ethylbenzene 4.29
    MIBK 42.49
    2-propoxyethanol 138.47
    tert-butanol 94.84
    MTBE 32.79
    2-butoxyethanol 64.3
    propionic acid 59.41
    o-xylene 8.87
    formic acid 129.69
    diethyl ether 52.04
    m-xylene 10.5
    p-xylene 4.75
    chlorobenzene 5.51
    dimethyl carbonate 58.77
    n-octane 2.39
    formamide 216.56
    cyclopentanone 129.05
    2-pentanone 66.54
    anisole 16.82
    cyclopentyl methyl ether 75.51
    gamma-butyrolactone 141.16
    1-methoxy-2-propanol 252.73
    pyridine 32.9
    3-pentanone 41.17
    furfural 98.12
    n-dodecane 1.82
    diethylene glycol 164.33
    diisopropyl ether 17.66
    tert-amyl alcohol 48.2
    acetylacetone 83.22
    n-hexadecane 1.98
    acetophenone 20.23
    methyl propionate 56.75
    isopentyl acetate 18.72
    trichloroethylene 17.02
    n-nonanol 20.63
    cyclohexanol 37.54
    benzyl alcohol 22.77
    2-ethylhexanol 15.18
    isooctanol 15.1
    dipropyl ether 34.27
    1,2-dichlorobenzene 5.57
    ethyl lactate 43.37
    propylene carbonate 58.64
    n-methylformamide 189.09
    2-pentanol 44.29
    n-pentane 6.91
    1-propoxy-2-propanol 99.43
    1-methoxy-2-propyl acetate 57.22
    2-(2-methoxypropoxy) propanol 56.32
    mesitylene 8.91
    ε-caprolactone 47.49
    p-cymene 5.63
    epichlorohydrin 89.69
    1,1,1-trichloroethane 10.22
    2-aminoethanol 139.75
    morpholine-4-carbaldehyde 196.86
    sulfolane 224.92
    2,2,4-trimethylpentane 2.47
    2-methyltetrahydrofuran 80.57
    n-hexyl acetate 26.1
    isooctane 2.65
    2-(2-butoxyethoxy)ethanol 75.36
    sec-butyl acetate 16.62
    tert-butyl acetate 42.11
    decalin 2.03
    glycerin 225.15
    diglyme 110.39
    acrylic acid 61.57
    isopropyl myristate 14.1
    n-butyric acid 55.89
    acetyl acetate 24.55
    di(2-ethylhexyl) phthalate 13.76
    ethyl propionate 29.81
    nitromethane 142.93
    1,2-diethoxyethane 38.35
    benzonitrile 13.85
    trioctyl phosphate 15.15
    1-bromopropane 11.26
    gamma-valerolactone 157.17
    n-decanol 16.35
    triethyl phosphate 16.96
    4-methyl-2-pentanol 24.46
    propionitrile 28.28
    vinylene carbonate 39.65
    1,1,2-trichlorotrifluoroethane 82.26
    DMS 24.16
    cumene 3.98
    2-octanol 16.2
    2-hexanone 30.45
    octyl acetate 18.04
    limonene 8.82
    1,2-dimethoxyethane 132.05
    ethyl orthosilicate 16.16
    tributyl phosphate 15.81
    diacetone alcohol 89.83
    N,N-dimethylaniline 19.49
    acrylonitrile 35.62
    aniline 26.72
    1,3-propanediol 137.76
    bromobenzene 3.43
    dibromomethane 9.41
    1,1,2,2-tetrachloroethane 21.19
    2-methyl-cyclohexyl acetate 17.24
    tetrabutyl urea 26.94
    diisobutyl methanol 13.62
    2-phenylethanol 23.71
    styrene 4.4
    dioctyl adipate 20.17
    dimethyl sulfate 125.47
    ethyl butyrate 25.08
    methyl lactate 105.18
    butyl lactate 35.03
    diethyl carbonate 16.46
    propanediol butyl ether 70.34
    triethyl orthoformate 22.7
    p-tert-butyltoluene 7.04
    methyl 4-tert-butylbenzoate 37.51
    morpholine 125.01
    tert-butylamine 47.58
    n-dodecanol 12.56
    dimethoxymethane 236.16
    ethylene carbonate 37.2
    cyrene 67.09
    2-ethoxyethyl acetate 32.25
    2-ethylhexyl acetate 13.92
    1,2,4-trichlorobenzene 7.18
    4-methylpyridine 29.3
    dibutyl ether 15.38
    2,6-dimethyl-4-heptanol 13.62
    DEF 82.21
    dimethyl isosorbide 91.06
    tetrachloroethylene 14.09
    eugenol 46.63
    triacetin 32.12
    span 80 47.46
    1,4-butanediol 58.2
    1,1-dichloroethane 13.64
    2-methyl-1-pentanol 19.06
    methyl formate 124.34
    2-methyl-1-butanol 30.8
    n-decane 2.72
    butyronitrile 28.61
    3,7-dimethyl-1-octanol 14.7
    1-chlorooctane 7.24
    1-chlorotetradecane 3.86
    n-nonane 2.62
    undecane 2.19
    tert-butylcyclohexane 2.16
    cyclooctane 2.89
    cyclopentanol 78.64
    tetrahydropyran 53.56
    tert-amyl methyl ether 30.12
    2,5,8-trioxanonane 91.87
    1-hexene 8.59
    2-isopropoxyethanol 72.67
    2,2,2-trifluoroethanol 74.83
    methyl butyrate 33.6

    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