Phthalic anhydride

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  • Identifiers

    CAS number
    85-44-9

    Molecular formula
    C8H4O3

    SMILES
    C1=CC=C2C(=C1)C(=O)OC2=O

    Safety labels

    Corrosive
    Corrosive

    Irritant
    Irritant

    Health Hazard
    Health

  • Odor profile

    Fragrance
    Sweet 56.03%
    Coumarinic 44.86%
    Nutty 44.52%
    Phenolic 43.44%
    Coconut 38.07%
    Odorless 34.97%
    Burnt 34.38%
    Spicy 31.06%
    Balsamic 30.75%
    Tobacco 29.84%

     

    Flavor
    Bitter 59.31%
    Tonka 26.89%
    Balsam 26.22%
    Faint 21.32%
    Lovage 20.87%
    Fenugreek 20.61%
    Urine 20.24%
    Herbal 19.85%
    Seedy 19.43%
    Nitrile 19.34%

     

    Odor impact est.
    Low

    Odor threshold

    • Odor Threshold Low: 0.05 [mmHg]. Odor threshold from AIHA
    • Air: 0.053 ul/l; odor safety class C; C= Less than 50% of distracted persons perceive warning of TLV.
    • 0.32-0.72 mg/cu m

  • Properties

    XLogP3-AA
    1.3

    pKa est.
    7.75 (neutral)

    Molecular weight
    148.11 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Very slow

    Melting point expt.

    • 267.4 °F (NTP, 1992)
    • 131.4 °C
    • 131 °C
    • 267.4 °F
    • 267 °F

    Boiling point

    • 563 °F at 760 mmHg (sublimes) (NTP, 1992)
    • 285.3 °C
    • Sublimes below the boiling point
    • 284 °C (sublimes)
    • 563 °F

    Flash point

    • 160.77 ˚C est.
    • 305 °F (NTP, 1992)
    • 305 °F (152 °C) (Closed cup)
    • 329 °F (Open cup); 305 °F (Closed cup)
    • 152 °C c.c.
    • 305 °F

    Solubility expt.

    • Decomposes (NTP, 1992)
    • In water, 6,000 mg/L at 25 °C
    • In water, 6,200 mg/L at 26 °C; 5,964 mg/L at room temperature
    • In water, 6,200 to 6,400 mg/L at 20-25 °C
    • In water, 16,400 mg/L including rapid hydrolysis to phthalic acid
    • For more Solubility (Complete) data for PHTHALIC ANHYDRIDE (7 total), please visit the HSDB record page.
    • Solubility in water, g/l at 20 °C: 6 (reaction)
    • 0.6%

  • Synonyms

    • PHTHALIC ANHYDRIDE
    • 85-44-9
    • Isobenzofuran-1,3-dione
    • 1,3-Isobenzofurandione
    • 2-Benzofuran-1,3-dione
    • 1,3-Dioxophthalan
    • 1,3-Phthalandione
    • Phthalsaeureanhydrid
    • o-Phthalic acid anhydride
    • Phthalic acid anhydride
    • Phthalandione
    • Retarder esen
    • Retarder AK
    • Retarder PD
    • Vulkalent B/C
    • Anidride ftalica
    • ESEN
    • Ftalowy bezwodnik
    • Ftaalzuuranhydride
    • Anhydride phtalique
    • Ftalanhydrid
    • 1,2-Benzenedicarboxylic anhydride
    • 1,2-Benzenedicarboxylic acid anhydride
    • Vulkalent B
    • Wiltrol P
    • Phthalanhydride
    • RCRA waste number U190
    • NCI-C03601
    • TGL 6525
    • Anhydrid kyseliny ftalove
    • Sconoc 7
    • Araldite HT 901
    • ortho-phthalic acid anhydride
    • CCRIS 519
    • NSC 10431
    • 1,3-dihydro-2-benzofuran-1,3-dione
    • CHEBI:36605
    • HSDB 4012
    • Isobenzofuran, 1,3-dihydro-1,3-dioxo-
    • phtalic anhydride
    • UNII-UVL263I5BJ
    • EINECS 201-607-5
    • UVL263I5BJ
    • MFCD00005918
    • DTXSID2021159
    • AI3-04869
    • Ht 901
    • NSC-10431
    • DTXCID401159
    • EC 201-607-5
    • Ftalanhydrid [Czech]
    • Ftaalzuuranhydride [Dutch]
    • Anidride ftalica [Italian]
    • Ftalowy bezwodnik [Polish]
    • Retarder B-C
    • Anhydride phtalique [French]
    • Phthalsaeureanhydrid [German]
    • Anhydrid kyseliny ftalove [Czech]
    • UN2214
    • RCRA waste no. U190
    • Phthalic anhydride (molten)
    • Phthalic Anhydride (May Contain Up To 15% Of Phthalic Acid)
    • pthalic anhydride
    • Retarder PX
    • o-phthalic anhydride
    • 1,3-dihydro-1,3-dioxoisobenzofuran
    • PhthalicAcidAnhydride-d4
    • isobenzofurane-1,3-dione
    • SCHEMBL220
    • Epitope ID:112744
    • WLN: T56 BVOVJ
    • 1,3-DIOXOPHTHALANE
    • 1,3-DIOXONAPHTHALAN
    • 2-Benzofuran-1,3-dione #
    • UN 2214 (Salt/Mix)
    • Phthalic anhydride treated BSA
    • Phthalic anhydride treated HSA
    • Phthalic anhydride, ACS grade
    • PHTHALIC ANHYDRIDE [MI]
    • CHEMBL1371297
    • PHTHALIC ANHYDRIDE [HSDB]
    • Phthalic anhydride treated gelatin
    • Phthalic anhydride treated casein I
    • NSC10431
    • Phthalic anhydride treated casein II
    • Tox21_200142
    • 1,3-dihydroisobenzofuran-1,3-dione
    • Isobenzofuran,3-dihydro-1,3-dioxo-
    • MSK002114
    • STL194302
    • AKOS000121309
    • FP33075
    • CAS-85-44-9
    • NCGC00091060-01
    • NCGC00091060-02
    • NCGC00257696-01
    • BP-30002
    • Phthalic anhydride, ACS reagent, >=99%
    • PS-10628
    • Phthalic anhydride, for synthesis, 99.0%
    • Phthalic anhydride, ReagentPlus(R), 99%
    • 1ST002114
    • 1,3-DIHYDRO-1,3-DIOXOISOBENZOFURANE
    • NS00004500
    • P1614
    • Phthalic anhydride, purum, >=97.0% (NT)
    • EN300-18017
    • P60058
    • Phthalic anhydride with >0.05% maleic anhydride
    • Phthalic anhydride, SAJ first grade, >=99.0%
    • A841333
    • Q410882
    • F1908-0105
    • InChI=1/C8H4O3/c9-7-5-3-1-2-4-6(5)8(10)11-7/h1-4
    • Phthalic anhydride with >0.05% maleic anhydride [UN2214] [Corrosive]
    • Phthalic anhydride, anhydrous, free-flowing, Redi-Dri(TM), ACS reagent, >=99%
    • 201-607-5

  • Applications

    Phthalic anhydride (CAS 85-44-9) is a versatile chemical intermediate widely used in industry for polymer and plasticizer production. It is a key feedstock for alkyd resins and unsaturated polyester resins used in coatings, paints, and fiberglass-reinforced composites; it also serves as the precursor to phthalate ester plasticizers that impart flexibility to PVC and other polymers. In the pigment and dye sector, it provides intermediates for dye and pigment chemistry, while in organic synthesis it is converted to phthalimide and related imides used as pharmaceutical and agrochemical intermediates. The material thus supports coatings, plastics, dyes, and specialty chemical applications, with use subject to local regulations and formulation constraints.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 42.51
    methanol 66.46
    isopropanol 32.22
    water 0.19
    ethyl acetate 54.2
    n-propanol 31.63
    acetone 127.46
    n-butanol 33.07
    acetonitrile 105.02
    DMF 656.11
    toluene 9.45
    isobutanol 20.26
    1,4-dioxane 120.52
    methyl acetate 91.36
    THF 186.24
    2-butanone 75.82
    n-pentanol 29.04
    sec-butanol 34.3
    n-hexane 1.54
    ethylene glycol 30.39
    NMP 240.82
    cyclohexane 1.06
    DMSO 335.75
    n-butyl acetate 42.22
    n-octanol 48.07
    chloroform 42.15
    n-propyl acetate 31.56
    acetic acid 35.53
    dichloromethane 43.11
    cyclohexanone 65.74
    propylene glycol 26.32
    isopropyl acetate 39.05
    DMAc 308.85
    2-ethoxyethanol 108.75
    isopentanol 30.27
    n-heptane 2.16
    ethyl formate 56.73
    1,2-dichloroethane 55.1
    n-hexanol 34.3
    2-methoxyethanol 251.89
    isobutyl acetate 17.11
    tetrachloromethane 5.3
    n-pentyl acetate 44.6
    transcutol 741.87
    n-heptanol 26.65
    ethylbenzene 11.29
    MIBK 44.46
    2-propoxyethanol 125.46
    tert-butanol 44.45
    MTBE 35.16
    2-butoxyethanol 80.75
    propionic acid 31.54
    o-xylene 10.86
    formic acid 31.66
    diethyl ether 44.21
    m-xylene 11.85
    p-xylene 13.0
    chlorobenzene 24.81
    dimethyl carbonate 80.95
    n-octane 2.3
    formamide 106.57
    cyclopentanone 110.4
    2-pentanone 67.33
    anisole 54.01
    cyclopentyl methyl ether 48.64
    gamma-butyrolactone 137.24
    1-methoxy-2-propanol 169.48
    pyridine 65.83
    3-pentanone 39.98
    furfural 158.36
    n-dodecane 3.81
    diethylene glycol 137.78
    diisopropyl ether 13.12
    tert-amyl alcohol 41.36
    acetylacetone 119.55
    n-hexadecane 4.46
    acetophenone 52.15
    methyl propionate 72.29
    isopentyl acetate 38.46
    trichloroethylene 90.92
    n-nonanol 43.59
    cyclohexanol 23.32
    benzyl alcohol 39.21
    2-ethylhexanol 21.68
    isooctanol 21.57
    dipropyl ether 25.48
    1,2-dichlorobenzene 33.88
    ethyl lactate 44.04
    propylene carbonate 69.03
    n-methylformamide 213.2
    2-pentanol 27.22
    n-pentane 1.26
    1-propoxy-2-propanol 82.39
    1-methoxy-2-propyl acetate 80.25
    2-(2-methoxypropoxy) propanol 129.1
    mesitylene 10.35
    ε-caprolactone 65.41
    p-cymene 12.46
    epichlorohydrin 169.36
    1,1,1-trichloroethane 30.73
    2-aminoethanol 41.97
    morpholine-4-carbaldehyde 288.73
    sulfolane 185.94
    2,2,4-trimethylpentane 1.44
    2-methyltetrahydrofuran 73.49
    n-hexyl acetate 85.93
    isooctane 1.49
    2-(2-butoxyethoxy)ethanol 204.57
    sec-butyl acetate 23.02
    tert-butyl acetate 50.17
    decalin 2.57
    glycerin 63.54
    diglyme 320.17
    acrylic acid 38.67
    isopropyl myristate 35.55
    n-butyric acid 39.04
    acetyl acetate 41.64
    di(2-ethylhexyl) phthalate 32.2
    ethyl propionate 36.1
    nitromethane 230.31
    1,2-diethoxyethane 119.0
    benzonitrile 53.84
    trioctyl phosphate 28.11
    1-bromopropane 19.56
    gamma-valerolactone 176.06
    n-decanol 34.06
    triethyl phosphate 26.78
    4-methyl-2-pentanol 19.22
    propionitrile 59.88
    vinylene carbonate 64.18
    1,1,2-trichlorotrifluoroethane 119.41
    DMS 89.52
    cumene 10.07
    2-octanol 27.38
    2-hexanone 42.75
    octyl acetate 46.29
    limonene 14.6
    1,2-dimethoxyethane 201.03
    ethyl orthosilicate 23.11
    tributyl phosphate 33.45
    diacetone alcohol 88.45
    N,N-dimethylaniline 42.8
    acrylonitrile 111.75
    aniline 26.7
    1,3-propanediol 65.57
    bromobenzene 21.53
    dibromomethane 24.98
    1,1,2,2-tetrachloroethane 75.66
    2-methyl-cyclohexyl acetate 28.71
    tetrabutyl urea 54.06
    diisobutyl methanol 18.91
    2-phenylethanol 48.15
    styrene 13.5
    dioctyl adipate 45.12
    dimethyl sulfate 134.45
    ethyl butyrate 31.19
    methyl lactate 92.27
    butyl lactate 54.12
    diethyl carbonate 27.11
    propanediol butyl ether 119.41
    triethyl orthoformate 30.46
    p-tert-butyltoluene 13.27
    methyl 4-tert-butylbenzoate 68.56
    morpholine 142.42
    tert-butylamine 20.62
    n-dodecanol 27.07
    dimethoxymethane 266.52
    ethylene carbonate 47.6
    cyrene 72.97
    2-ethoxyethyl acetate 84.34
    2-ethylhexyl acetate 28.27
    1,2,4-trichlorobenzene 39.77
    4-methylpyridine 65.59
    dibutyl ether 50.32
    2,6-dimethyl-4-heptanol 18.91
    DEF 130.87
    dimethyl isosorbide 155.77
    tetrachloroethylene 42.79
    eugenol 91.71
    triacetin 85.98
    span 80 77.34
    1,4-butanediol 30.54
    1,1-dichloroethane 30.52
    2-methyl-1-pentanol 28.13
    methyl formate 158.93
    2-methyl-1-butanol 26.54
    n-decane 5.19
    butyronitrile 53.62
    3,7-dimethyl-1-octanol 40.4
    1-chlorooctane 24.3
    1-chlorotetradecane 12.36
    n-nonane 4.42
    undecane 4.41
    tert-butylcyclohexane 2.46
    cyclooctane 0.86
    cyclopentanol 33.15
    tetrahydropyran 47.82
    tert-amyl methyl ether 36.65
    2,5,8-trioxanonane 240.01
    1-hexene 7.78
    2-isopropoxyethanol 66.72
    2,2,2-trifluoroethanol 28.45
    methyl butyrate 47.78

    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