p-Toluenesulfonic acid

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  • Identifiers

    CAS number
    104-15-4

    Molecular formula
    C7H8O3S

    SMILES
    CC1=CC=C(C=C1)S(=O)(=O)O

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 75.65%
    Sulfurous 23.82%
    Bitter 22.14%
    Burnt 21.2%
    Cooked 20.92%
    Roasted 19.78%
    Pungent 17.78%
    Savory 17.57%
    Phenolic 15.2%
    Aromatic 14.96%

     

    Flavor
    Bitter 67.5%
    Odorless 24.67%
    Nitrile 21.77%
    Urine 20.91%
    Phenolic 20.29%
    Balsam 20.12%
    Almond shell 19.97%
    Very strong 19.64%
    Indole 19.47%
    Bread crust 19.42%

     

    Odor impact est.
    Medium

  • Properties

    XLogP3-AA
    1.7

    pKa est.
    8.55 (weak base)

    Molecular weight
    172.2 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Melting point expt.

    • 221 °F (USCG, 1999)
    • 106-107 °C
    • 106-107 °C /ANHYDROUS/
    • MELTING POINT: 38 °C /METASTABLE FORM/
    • Melting point = 106 °C /monohydrate/; 93 °C /trihydrate/
    • 104.50 °C. @ 760.00 mm Hg

    Boiling point

    • 140 °C @ 20 MM HG
    • Boiling point = 38 °C

    Flash point

    • 165.71 ˚C est.
    • 363 °F (184 °C) (CLOSED CUP)
    • 184 °C c.c.

    Solubility expt.

    • ABOUT 67 G/100 ML WATER; SOL IN ALCOHOL, ETHER
    • VERY SOL IN WATER /SODIUM SALT/
    • Solubility in water, g/100ml at 25 °C: 67 (freely soluble)

  • Synonyms

    • 4-Methylbenzenesulfonic acid
    • P-TOLUENESULFONIC ACID
    • 104-15-4
    • 4-Toluenesulfonic acid
    • p-Toluenesulphonic acid
    • Tosic acid
    • Toluene-4-sulfonic acid
    • p-Tolylsulfonic acid
    • Tosylic acid
    • Toluenesulfonic acid
    • Benzenesulfonic acid, 4-methyl-
    • p-Methylbenzenesulfonic acid
    • p-Methylphenylsulfonic acid
    • Eltesol
    • Methylbenzenesulfonic acid
    • Cyclophil P T S A
    • Nacure 1040
    • Cyzac 4040
    • Kyselina p-toluenesulfonova
    • Manro PTSA 65 E
    • Manro PTSA 65 H
    • Manro PTSA 65 LS
    • K-Cure 1040
    • p-toluene sulphonic acid
    • para-toluenesulfonic acid
    • Eltesol TSX
    • QGV5ZG5741
    • DTXSID0026701
    • NSC-2167
    • NSC-167068
    • DTXCID406701
    • CHEBI:27849
    • PTS-100
    • RefChem:6095
    • 203-180-0
    • PARA-TOLUENE SULFONATE
    • P-Toluene Sulfonic acid
    • PTSA
    • ar-Toluenesulfonic acid
    • p-Toluolenesulfonic acid
    • p-Toluene sulfonate
    • Toluene-4-sulphonic acid
    • Toluene sulfonic acid
    • TSA-HP
    • TSA-MH
    • Benzenesulfonic acid, methyl-
    • Kyselina p-toluensulfonova
    • Toluene-p-sulfonate
    • Toluen-4-sulfonsaeure
    • toluene-p-sulfonic acid
    • NSC 167068
    • p-toluensulfonic acid
    • 4-methylbenzene-1-sulfonic acid
    • p-Toluene-sulfonic acid
    • para-toluenesulphonic acid
    • paratoluene sulphonic acid
    • para toluene sulfonic acid
    • 4-Toluene sulfonic acid
    • CHEMBL541253
    • 4-TOLUENE-SULFONIC ACID
    • MFCD00064387
    • TsOH
    • WLN: WSQR D1
    • p-TSA
    • Toluenesulfonic acid (VAN)
    • HSDB 2026
    • Xylometazoline EP Impurity E
    • K-Cure 040
    • TSU
    • Kyselina p-toluensulfonova [Czech]
    • Kyselina p-toluenesulfonova [Czech]
    • EINECS 203-180-0
    • BRN 0472690
    • UNII-QGV5ZG5741
    • TosicAcid
    • 4-sulphotoluene
    • AI3-26478
    • CYZAC-4040
    • 2(Or 4)-toluenesulphonic acid
    • pTsOH
    • TosOH
    • p-toluenesulfonicacid
    • p-TsOH
    • Tos-OH
    • p-toluenesufonic acid
    • 4-Toluenesulfonicacid
    • p-toluene sulfonicacid
    • p-toluene-sulfonicacid
    • p-toluensulphonic acid
    • paratoluensulfonic acid
    • Ts-OH
    • p-toluen sulfonic acid
    • p-toluenesuiphonic acid
    • p-toluenylsulfonic acid
    • paratoluenesulfonic acid
    • 4-toluenesulphonic acid
    • p -toluenesulfonic acid
    • p- toluenesulfonic acid
    • p-tolu-enesulfonic acid
    • p-toluyl sulphonic acid
    • toluene p-sulfonic acid
    • para-toluensulfonic acid
    • rho-toluenesulfonic acid
    • paratoluenesulphonic acid
    • p-toluene-sulphonic acid
    • toluene 4-sulfonic acid
    • toluene p-sulphonic acid
    • toluene-p-sulphonic acid
    • para toluenesulfonic acid
    • paratoluene sulfonic acid
    • paratoluene-sulfonic acid
    • SCHEMBL34
    • 4-toluene sulphonic acid
    • 4-toluene-sulphonic acid
    • rho-toluene sulfonic acid
    • para toluenesulphonic acid
    • para-toluene sulfonic acid
    • para-toluene-sulfonic acid
    • 4methylbenzenesulfonic acid
    • SCHEMBL927
    • 4-methylphenylsulfonic acid
    • ACTIVATOR-100T3
    • para-toluene sulphonic acid
    • TAYCATOX-300
    • EC 203-180-0
    • 4-methylphenylsulphonic acid
    • NCIOpen2_002932
    • 104-15-4

  • Applications

    p-Toluenesulfonic acid (CAS 104-15-4) is a strong Brønsted acid used primarily as a catalyst in organic synthesis. Real-world applications include: (1) catalyzing esterification and transesterification to generate esters for chemical products, fragrances, and biodiesel; (2) acetalization to protect carbonyl groups in organic synthesis sequences; (3) glycosylation and other carbohydrate reactions in carbohydrate chemistry; (4) synthesis of pharmaceutical intermediates and fine chemicals where strong acid catalysis is required for reactions such as acylation, etherification, and dehydration; (5) catalyzing polymerization and resin/coat formulations in coatings, inks, and adhesives; (6) used as an organic acid catalyst in the production of fragrance esters and related precursors.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 68.34
    methanol 62.49
    isopropanol 46.58
    water 1.22
    ethyl acetate 48.55
    n-propanol 45.08
    acetone 107.06
    n-butanol 39.93
    acetonitrile 63.97
    DMF 340.79
    toluene 2.05
    isobutanol 23.78
    1,4-dioxane 119.63
    methyl acetate 76.88
    THF 190.37
    2-butanone 89.5
    n-pentanol 27.77
    sec-butanol 38.04
    n-hexane 0.24
    ethylene glycol 21.72
    NMP 333.45
    cyclohexane 0.6
    DMSO 177.5
    n-butyl acetate 34.61
    n-octanol 16.56
    chloroform 4.22
    n-propyl acetate 29.84
    acetic acid 82.17
    dichloromethane 12.2
    cyclohexanone 122.63
    propylene glycol 39.15
    isopropyl acetate 29.51
    DMAc 273.58
    2-ethoxyethanol 75.31
    isopentanol 29.86
    n-heptane 1.04
    ethyl formate 44.9
    1,2-dichloroethane 14.72
    n-hexanol 31.73
    2-methoxyethanol 140.32
    isobutyl acetate 12.18
    tetrachloromethane 0.75
    n-pentyl acetate 25.17
    transcutol 89.41
    n-heptanol 20.68
    ethylbenzene 2.72
    MIBK 27.74
    2-propoxyethanol 76.87
    tert-butanol 49.99
    MTBE 18.71
    2-butoxyethanol 44.52
    propionic acid 58.09
    o-xylene 3.81
    formic acid 41.93
    diethyl ether 13.26
    m-xylene 2.95
    p-xylene 4.42
    chlorobenzene 6.98
    dimethyl carbonate 25.13
    n-octane 0.52
    formamide 153.94
    cyclopentanone 216.99
    2-pentanone 55.58
    anisole 22.95
    cyclopentyl methyl ether 27.91
    gamma-butyrolactone 219.6
    1-methoxy-2-propanol 95.23
    pyridine 53.7
    3-pentanone 31.95
    furfural 134.18
    n-dodecane 0.77
    diethylene glycol 61.32
    diisopropyl ether 4.4
    tert-amyl alcohol 38.79
    acetylacetone 91.18
    n-hexadecane 0.87
    acetophenone 38.42
    methyl propionate 44.97
    isopentyl acetate 28.83
    trichloroethylene 21.77
    n-nonanol 16.21
    cyclohexanol 24.89
    benzyl alcohol 26.52
    2-ethylhexanol 17.46
    isooctanol 15.85
    dipropyl ether 13.17
    1,2-dichlorobenzene 9.12
    ethyl lactate 24.08
    propylene carbonate 83.35
    n-methylformamide 142.21
    2-pentanol 21.68
    n-pentane 0.36
    1-propoxy-2-propanol 48.02
    1-methoxy-2-propyl acetate 50.56
    2-(2-methoxypropoxy) propanol 47.11
    mesitylene 2.77
    ε-caprolactone 103.65
    p-cymene 6.81
    epichlorohydrin 133.88
    1,1,1-trichloroethane 6.83
    2-aminoethanol 45.04
    morpholine-4-carbaldehyde 226.32
    sulfolane 213.47
    2,2,4-trimethylpentane 0.43
    2-methyltetrahydrofuran 83.56
    n-hexyl acetate 29.26
    isooctane 0.36
    2-(2-butoxyethoxy)ethanol 56.19
    sec-butyl acetate 17.52
    tert-butyl acetate 33.75
    decalin 0.62
    glycerin 54.17
    diglyme 92.71
    acrylic acid 55.78
    isopropyl myristate 13.92
    n-butyric acid 56.15
    acetyl acetate 33.73
    di(2-ethylhexyl) phthalate 18.47
    ethyl propionate 22.22
    nitromethane 220.49
    1,2-diethoxyethane 30.72
    benzonitrile 28.89
    trioctyl phosphate 14.65
    1-bromopropane 3.84
    gamma-valerolactone 262.46
    n-decanol 13.52
    triethyl phosphate 14.77
    4-methyl-2-pentanol 12.55
    propionitrile 33.61
    vinylene carbonate 58.4
    1,1,2-trichlorotrifluoroethane 68.83
    DMS 26.93
    cumene 3.15
    2-octanol 12.99
    2-hexanone 33.37
    octyl acetate 20.0
    limonene 9.47
    1,2-dimethoxyethane 97.21
    ethyl orthosilicate 12.75
    tributyl phosphate 14.87
    diacetone alcohol 76.21
    N,N-dimethylaniline 19.07
    acrylonitrile 59.5
    aniline 15.83
    1,3-propanediol 66.13
    bromobenzene 4.0
    dibromomethane 4.79
    1,1,2,2-tetrachloroethane 18.02
    2-methyl-cyclohexyl acetate 27.36
    tetrabutyl urea 25.93
    diisobutyl methanol 11.01
    2-phenylethanol 34.65
    styrene 3.05
    dioctyl adipate 24.38
    dimethyl sulfate 49.22
    ethyl butyrate 26.83
    methyl lactate 43.02
    butyl lactate 25.05
    diethyl carbonate 17.17
    propanediol butyl ether 39.14
    triethyl orthoformate 17.5
    p-tert-butyltoluene 6.67
    methyl 4-tert-butylbenzoate 39.27
    morpholine 144.88
    tert-butylamine 17.8
    n-dodecanol 10.51
    dimethoxymethane 75.5
    ethylene carbonate 43.9
    cyrene 75.58
    2-ethoxyethyl acetate 38.78
    2-ethylhexyl acetate 21.32
    1,2,4-trichlorobenzene 15.6
    4-methylpyridine 38.7
    dibutyl ether 11.0
    2,6-dimethyl-4-heptanol 11.01
    DEF 81.84
    dimethyl isosorbide 86.26
    tetrachloroethylene 8.47
    eugenol 40.16
    triacetin 35.64
    span 80 41.27
    1,4-butanediol 27.93
    1,1-dichloroethane 7.71
    2-methyl-1-pentanol 21.41
    methyl formate 86.77
    2-methyl-1-butanol 25.11
    n-decane 0.95
    butyronitrile 31.03
    3,7-dimethyl-1-octanol 15.54
    1-chlorooctane 4.66
    1-chlorotetradecane 2.63
    n-nonane 0.74
    undecane 0.88
    tert-butylcyclohexane 0.56
    cyclooctane 0.24
    cyclopentanol 48.2
    tetrahydropyran 48.95
    tert-amyl methyl ether 15.83
    2,5,8-trioxanonane 77.86
    1-hexene 1.55
    2-isopropoxyethanol 45.17
    2,2,2-trifluoroethanol 35.28
    methyl butyrate 35.06

    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