Basic information description Chemical properties Uses Production method Toxicity Usage limit Safety Related Supplier
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Basic information description Chemical properties Uses Production method Toxicity Usage limit Safety Related Supplier
p-Cresol Basic information
p-Cresol Chemical Properties
  • Melting point:32-34 °C(lit.)
  • Boiling point:202 °C(lit.)
  • Density 1.034 g/mL at 25 °C(lit.)
  • vapor density 3.72 (vs air)
  • vapor pressure 1 mm Hg ( 20 °C)
  • refractive index nD20 1.5395
  • FEMA 2337 | P-CRESOL
  • Flash point:193 °F
  • storage temp. 2-8°C
  • solubility 20g/l
  • pka10.17(at 25℃)
  • form Crystalline Solid or Liquid
  • color Colorless to light yellow, may darken on exposure to light
  • Specific Gravity1.0341 (20/4℃)
  • Odor Threshold0.000054ppm
  • explosive limit1%(V)
  • Water Solubility 20 g/L (20 ºC)
  • Sensitive Light Sensitive
  • Merck 14,2579
  • JECFA Number693
  • BRN 1305151
  • Henry's Law Constant6.17 at 20.00 °C, 9.31 at 25.00 °C (dynamic equilibrium system-GC, Feigenbrugel et al., 2004a)
  • Exposure limitsNIOSH REL: TWA 2.3 ppm (10 mg/m3), IDLH 250 ppm; OSHA PEL: TWA 5 ppm (22 mg/m3); ACGIH TLV: TWA for all isomers 5 ppm (adopted).
  • Stability:Stable. Combustible. Incompatible with strong oxidizing agents. Air and light-sensitive. Hygroscopic.
  • CAS DataBase Reference106-44-5(CAS DataBase Reference)
  • NIST Chemistry ReferencePhenol, 4-methyl-(106-44-5)
  • EPA Substance Registry Systemp-Cresol (106-44-5)
Safety Information
p-Cresol Usage And Synthesis
  • descriptionp-Cresol is a low-molecular-weight compound, is a starting material in the synthesis of bupranolol which is a non-selective beta blocker.
    p-cresol is found in extracts from the plants Mentha pulegium and Hedeoma pulegioides, commonly known as pennyroyal oil and pennyroyal tea. These extracts are popular as unconventional herbal therapeutic agents and are applied as abortiva, diaphoretics, emmenagogues, and psychedelic drugs. Pennyroyal oil is extensively used for its pleasant mint-like smell in the flavoring industry.
    It is also used in the production of antioxidants like butylated hydroxytoluene. Furthermore, it is used as an adhesive and a sealant in chemicals, dyes, intermediates, odor agents, plasticizers, plating agents and surface treating agents. It acts as an antioxidant and a disinfectant in pharmaceuticals.
  • Chemical propertiesIt appears as colorless to pink crystal with smoked and herbal smell. The relative density (d420) is 1.0178; the refractive index (nD20) is 1.5312; the melting point is 34.8 °C; the boiling point is 201.9 °C and the flash point is 86.1 °C. It is soluble in water (2.3%/40 ℃), easily soluble in caustic soda and common organic solvents.
    Natural products exist in ylang oil, strawberry, cheese, coffee and cocoa and so on.
  • Uses1. It can be used as germicide, fungicide. Used for organic Synthesis.
    2. This product is the raw material for the manufacture of antioxidant 2,6-di-tert-butyl-p-cresol and rubber antioxidant. At the same time, it is also an important fundamental raw material for the production of pharmaceutical TMP and dyes para-Cresidine sulfonic acid.
    3. P-cresol is the intermediate for the manufacturing of fungicide methylphosophos, an insecticide flufenvalerate, and Etofenprox, but also the intermediate of antioxidant additives 2, 6-di-tert-butyl-4-methyl phenol and p-hydroxybenzene formaldehyde.
    4. It can be used as raw materials for the preparation of antioxidant 264 (2, 6-di-tert-butyl-p-cresol) and rubber antioxidant. In the plastics industry, it can produce phenolic resin and plasticizer. In medicine, it can be used as a disinfectant. In addition, it can be used as the raw materials of dyes and pesticides.
  • Production method1. The mother liquor of using the para, m-cresol mixture for the extraction of m-cresol can be subject to recrystallization using oxalic acid addition method. 2. Toluene and sulfuric acid can be subject to sulfonation and neutralization to generate sodium p-toluenesulfonate followed by alkali melting, acidification and distillation to get the finished product p-cresol. In order to obtain high purity p-cresol, there are two processes: (1) the distilled p-cresol is subject to further crystallization and separation; (2) the p-toluenesulfonic acid after sulfonation is further subject to cooling, crystallization, filtration, and then neutralization, alkali melting, acidification and distillation to derive the products.
    The Nanjing Jinyan Chemical Corporation has developed mature sulfonated alkali melting technology, being able to produce high purity p-cresol. With changing the process conditions, the same device can also enable the production of m-cresol, o-cresol, phenol, and naphthol.
    There are several preparation methods as follows.
    (1) Toluene sulfonation alkali melting method
    The sulfonation reaction is carried out at 110-130 °C using toluene as raw material to produce intermediate toluene sulfonic acid. After neutralization, it further has alkali melting reaction with the molten sodium hydroxide at 340-365 °C to obtain Cresol sodium which further converts to crude cresol after the acidification, followed by distillation for separation of o-cresol and phenol, to get the mixed p-, m-cresol with p-cresol being the major part. The composition of isomers in cresol was determined by the temperature, the type of sulfonating agent and the ratio of toluene to sulfonating agent. Nanjing Jinyan Chemical Corporation can produce high purity p-cresol by sulfonation alkali fusion. Commonly used sulfonating agents also include fuming sulfuric acid and chlorosulfonic acid.
    Preparation of p-cresol by toluene sulfonation is the earliest industrial process, this method is more mature, but need to consume a lot of acid, alkali, equipment corrosion problems. This method is currently still the main method of production of p-cresol.
    The mother liquor of p-, m-cresol mixture after extraction of m-cresol can be subject to recrystallization using oxalic acid addition method. For example, the urea can be heated together with the filtered toluene solution to 95~100 ° C. Further add under stirring of oxalic acid for reaction of 2~3h, and then cooled at room temperature for about 16h, with vacuum filtration to obtain the white crystals, namely the p-cresol oxalic acid complex. The complex was decomposed with hot water. The supernatant oil layer was firstly distilled to toluene and steamed, followed by cutting the 93-104 ° C fraction at 0.094 MPa to obtain the p-cresol with a purity of 95%.
     (2) p-toluidine diazo hydrolysis method
    P-toluidine can react with sulfuric acid to form p-toluidine sulfate, further subject to sodium nitrite diazotization at 0~5 ℃. The diazonium salt is put into the dilute sulfuric acid for heating hydrolysis and the oil product is further separated out by the steam. The oil layer is further added into the 1% sodium hydroxide, followed by decolorization filtering. Add concentrated sulfuric acid to pH = 1, and then separate out the water layer, add zinc powder and sulfuric acid, and then neutralize to neutral with sodium carbonate; separate the oil product; wash, and then apply vacuum distillation to get the finished product.
    (3) Separation of kerosene derived
    Apply sulfuric acid for the sulfonation of toluene to obtain p-toluenesulfonic acid, followed by cooling, crystallization, filtration, and then addition of sodium sulfite for neutralization to obtain the sodium p-toluene sulfonate, with further sulfide acidification to derive the final product which is finally subject to distillation and crystallization separation.
  • ToxicityCentral nervous system: toxic effects with being fatal in severe cases.
    LD50:1800 mg/kg (rat, oral);
    As fragrances, it can be safely used in food (FDA, §172.515, 2000);
    GRAS (FEMA).
  • Usage limitFEMA (mg/kg): soft drinks 0.67; cold drinks 0.01 to 1.0; candies and baked goods 0.01 to 2.0.
  • Chemical PropertiesColorless to pink crystals with a phenolic odor. Odor threshold concentration in water is 55 ppb (Buttery et al., 1988). An experimentally determined odor threshold concentration of 1 ppbv was reported by Leonardos et al. (1969) which exceeds the odor threshold concentration of 0.054 ppbv reported by Nagata and Takeuchi (1990).
  • Chemical PropertiesCresol is a mixture of the three isomeric cresols, o-, m-, and p-cresol. Cresols are slightly soluble in water. m-Isomer: Colorless or yellow liquid with characteristic odor.
  • Chemical Propertiesp-Cresol has a characteristics phenol-like odor.
  • Physical propertiesColorless to pink crystals with a phenolic odor. Odor threshold concentration in water is 55 ppb (Buttery et al., 1988). An experimentally determined odor threshold concentration of 1 ppbv was reported by Leonardos et al. (1969) which exceeds the odor threshold concentration of 0.054 ppbv reported by Nagata and Takeuchi (1990).
  • OccurrenceHas been found in a score of essential oils including ylang ylang and oil of jasmine (Gildemeister & Hoffman, 1966).
  • UsesIntermediates of Liquid Crystals
  • Usesp-Cresol is used in the synthesis of Bupranolol (B689650), a non-selective beta blocker.
  • UsesFor making synthetic resins; in disinfectants and fumigants; as industrial solvent; m-cresol in photographic developers, explosives.
  • DefinitionChEBI: A cresol that consists of toluene substituted by a hydroxy group at position 4. It is a metabolite of aromatic amino acid metabolism produced by intestinal microflora in humans and animals.
  • Production MethodsThe cresols (cresylic acids) are methyl phenols and generally appear as a mixture of isomers. p-Cresol is a 4-methyl derivative of phenol and is prepared from m-toluic acid or obtained from coal tar or petroleum. Crude cresol is obtained by distilling “gray phenic acid” at a temperature of ~180–201°C. p-Cresol may be separated from the crude or purified mixture by repeated fractional distillation in vacuo. It can also be prepared synthetically by diazotization of the specific toluene or by fusion of the corresponding toluenesulfonic acid with sodium hydroxide.
  • PreparationIt can be prepared by fractional distillation of coal tar where it occurs together with the ortho- and para- isomers.
  • Aroma threshold valuesDetection: 55 to 100 ppb.
  • General DescriptionColorless solid with a tar like odor. Sinks and mixes slowly with water.
  • Air & Water ReactionsInsoluble in water.
  • Reactivity Profilep-Cresol is sensitive to heat. p-Cresol is also sensitive to light. p-Cresol is incompatible with strong oxidizers and strong alkalis. p-Cresol will attack some forms of plastics, coatings and rubber.
  • HazardQuestionable carcinogen.
  • Health HazardINHALATION: Irritation of nose or throat. EYES: Intense irritation and pain, swelling of conjunctiva and corneal damage may occur. SKIN: Intense burning, loss of feeling, white discoloration and softening. Gangrene may occur. INGESTION: Burning sensation in mouth and esophagus. Vomiting may result. Absorption by all routes may cause muscular weakness, gastroenteric disturbance, severe depression and collapse. Effects are primarily on central nervous system, edema of lungs, injury of spleen and pancreas may occur.
  • Safety ProfilePoison by ingestion, skin contact, subcutaneous, intravenous, and intraperitoneal routes. A severe skin and eye irritant. Questionable carcinogen with experimental neoplastigenic data by itself and with 7,12-dirnethyl benz(a)anthracene. Combustible when exposed to heat or flame. Moderately explosive in the form ofvapor when exposed to heat or flame. To fight fire, use CO2, dry chemical, alcohol foam. See also other cresol entries and PHENOL.
  • Potential ExposureCresol is used as a disinfectant and fumigant; as an ore flotation agent, and as an intermediate in the manufacture of chemicals, dyes, plastics, and antioxidants. A mixture of isomers is generally used; the concentrations of the components are determined by the source of the cresol.
  • Carcinogenicityo-Cresol has been induced a few papillomas but no carcinomas in tumor studies.
  • SourceAs 3+4-methylphenol, detected in distilled water-soluble fractions of 87 octane gasoline (6.03 mg/L), 94 octane gasoline (0.60 mg/L), Gasohol (1.76 mg/L), No. 2 fuel oil (1.84 mg/L), jet fuel A (0.43 mg/L), diesel fuel (1.318 mg/L), and military jet fuel JP-4 (0.92 mg/L) (Potter, 1996).
    A high-temperature coal tar contained 4-methylphenol at an average concentration of 0.27 wt % (McNeil, 1983).
    Occurs naturally in brown juniper, Spanish cedar, peppermint (2 to 20 ppb), tarragon, asparagus shoots, ylang-ylang, jasmine, tea leaves, coffee beans, Japanese privet, white mulberries, raspberries, vanilla, blueberries, sour cherries, anise, and tamarind (Duke, 1992).
    A liquid swine manure sample collected from a waste storage basin contained 4-methylphenol at a concentration of 4.9 mg/L (Zahn et al., 1997).
  • Environmental FateBiological. Protocatechuic acid (3,4-dihydroxybenzoic acid) is the central metabolite in the bacterial degradation of 4-methylphenol. Intermediate by-products include 4-hydroxybenzyl alcohol, 4-hydroxybenzaldehyde, and 4-hydroxybenzoic acid. In addition, 4-methylphenol may undergo hydroxylation to form 4-methylcatechol (Chapman, 1972). Chloroperoxidase, a fungal enzyme isolated from Caldariomyces fumago, reacted with 4-methylphenol forming 4-methyl-2- chlorophenol (Wannstedt et al., 1990). Under methanogenic conditions, inocula from a municipal sewage treatment plant digester degraded 4-methylphenol to phenol prior to being mineralized to carbon dioxide and methane (Young and Rivera, 1985).
    Photolytic. Photooxidation products reported include 2,2′-dihydroxy-4,4′-dimethylbiphenyl, 2- hydroxy-3,4′-dimethylbiphenyl ether, and 4-methylcatechol (Smith et al., 1978). Anticipated products from the reaction of 4-methylphenol with ozone or OH radicals in the atmosphere are hydroxynitrotoluene and ring cleavage compounds (Cupitt, 1980). Absorbs UV light at a maximum wavelength of 278 nm (Dohnal and Fenclová, 1995).
    Chemical/Physical. Kanno et al. (1982) studied the aqueous reaction of 4-methylphenol and other substituted aromatic hydrocarbons (toluidine, 1-naphthylamine, phenol, 2- and 3- methylphenol, pyrocatechol, resorcinol, hydroquinone, and 1-naphthol) with hypochlorous acid in the presence of ammonium ion. They reported that the aromatic ring was not chlorinated as expected but was cleaved by chloramine forming cyanogen chloride. The amount of cyanogen chloride formed was increased as the pH was lowered (Kanno et al., 1982).
  • Metabolismp-Cresol is oxidized at the methyl group in both dogs and rabbits to yield ρ-hydroxybenzoic acid. In the rabbit up to 10% of oral doses of 0.25-0.5 g is excreted as free and conjugated p-hydroxybenzoic acid (Williams, 1959).
  • ShippingUN2076 Cresols, liquid, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 8-Corrosive material. UN3455 Cresols, solid, Hazard class: 6.1; Labels: 6.1- Poisonous materials, 8-Corrosive material.
  • Purification MethodsIt can be separated from m-cresol by fractional crystalisation of its melt. Purify it by distillation, by precipitation from *benzene solution with pet ether, and via its benzoate, as for phenol. Dry it under vacuum over P2O5. It has also been crystallised from pet ether (b 40-60o) and by conversion to sodium p-cresoxyacetate which, after crystallisation from water is decomposed by heating with HCl in an autoclave [Savard Ann Chim (Paris) 11 287 1929]. The 3,5-dinitrobenzoate (prepared with 3,5-dinitrobenzoyl chloride in dry pyridine, and recrystallised from EtOH or aqueous Me2CO) has m 189o. [Beilstein 6 II 2093.]
  • IncompatibilitiesVapors may form explosive mixture with air. Incompatible with strong acids; oxidizers, alkalies, aliphatic amines; amides, chlorosulfonic acid; oleum. Decomposes on heating, producing strong acids and bases, causing fire and explosion hazard. Liquid attacks some plastics and rubber. Attacks many metals.
  • Waste DisposalWastewaters may be subjected to biological treatment. Concentrations may be further reduced by ozone treatment. High concentration wastes may be destroyed in special waste incinerators.
p-Cresol Preparation Products And Raw materials
p-Cresol(106-44-5)Related Product Information
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