Basic information Description Chemical Properties Uses Production Methods References Safety Related Supplier
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Basic information Description Chemical Properties Uses Production Methods References Safety Related Supplier
p-Cymene Basic information
p-Cymene Chemical Properties
  • Melting point:-68 °C
  • Boiling point:176-178 °C(lit.)
  • Density 0.86 g/mL at 25 °C(lit.)
  • vapor density 4.62 (vs air)
  • vapor pressure 1.5 mm Hg ( 20 °C)
  • FEMA 2356 | P-CYMENE
  • refractive index n20/D 1.490(lit.)
  • Flash point:117 °F
  • storage temp. Flammables area
  • form Liquid
  • color Clear
  • OdorMild, pleasant; aromatic, solvent-type.
  • Odor Threshold0.057ppm
  • explosive limit5.6%
  • JECFA Number1325
  • Merck 14,2763
  • BRN 1903377
  • Stability:Stable. Flammable. Incompatible with strong oxidizing agents, strong acids, strong bases.
  • CAS DataBase Reference99-87-6(CAS DataBase Reference)
  • NIST Chemistry ReferenceBenzene, 1-methyl-4-(1-methylethyl)-(99-87-6)
  • EPA Substance Registry Systemp-Cymene (99-87-6)
Safety Information
  • Hazard Codes Xi
  • Risk Statements 10-36/37/38
  • Safety Statements 26-36
  • RIDADR UN 2046 3/PG 3
  • WGK Germany 2
  • RTECS GZ5950000
  • Autoignition Temperature817 °F
  • TSCA Yes
  • HazardClass 3
  • PackingGroup III
  • HS Code 29029090
  • Hazardous Substances Data99-87-6(Hazardous Substances Data)
  • ToxicityLD50 orally in rats: 4750 mg/kg (Jenner)
p-Cymene Usage And Synthesis
  • Descriptionp-Cymene is a naturally occurring compound, although it has two further geometric isomers, m-cymene (with meta-substituted alkyl groups) and o-cymene (with ortho-substituted alkyl groups) which do not occur naturally. p-Cymene is related to the monoterpenes. Monoterpenes themselves belong to the “terpenes”, a larger class of organic compounds, which are the most representative components of essential oils. chemical structure of p-cymene, indicating the benzene ring with methyl and isopropyl substitutions.
    chemical structure of p-cymene
    chemical structure of p-cymene
  • Chemical Propertiesp-Cymene has a citrusy aroma reminiscent of lemon. It is colorless liquid with a strong, characteristic odor reminiscent of carrot. It tends to darken with aging. It occurs naturally in orange peel oil, mandarin peel oil, satsuma mandarin peel oil, coldpressed lime peel oil, distilled lime peel oil, cinnamon leaf, etc. 4-isopropyltoluene has antimicrobial properties. It is used as a flavor ingredient permitted for direct addition to food for human consumption.
  • Usesp-Cymene is an alkyl aromatic hydrocarbon mainly used to study oxidation reactions under various conditions to synthesize highly valuable intermediates and building-blocks such as cymene hydroperoxide, 4-methyl acetophenone, 4-isopropyl benzyl alcohol, 4-isopropyl benzaldehyde and 4-isopropyl benzoic acid etc.
    Medicinally, p-cymene is used to prevent coughs and eliminate phlegm as well as being a flavouring agent, and being used in the production of fungicides and pesticides. It is considered to be “generally recognised as safe” (GRAS) by the U.S. Food and Drug Administration. Its potential in the prevention of protein glycation mediated diabetic complications has also been confirmed, and it has been suggested as an in vivo antioxidant compound due to its ability to reduce the formation of oxygen and nitrogen reactive species, acting as a potential neuroprotective agent in the brain. Therefore, it could be involved in the treatment of oxidative stress related diseases.
  • Production Methodsp-cymene is conventionally produced by the Friedel-Crafts alkylation of toluene with isopropanol, or of benzene with methyl or isopropyl halides.
  • References[1] George A. Burdock, Encyclopedia of Food and Color Additives, Volume 1, 1996
    [2] C.F. Bagamboula, M. Uyttendaele and J. Debevere, Inhibitory effect of thyme and basil essential oils, carvacrol, thymol, estragol, linalool and p-cymene towards Shigella sonnei and S. flexneri, Food Microbiology, 2004, vol. 21, 33-42
  • Chemical Propertiesp-Cymene is a monoterpene that is found in a variety of plants, including C. sativa, and has diverse biological activities, including antimicrobial, anticancer, antioxidant, anti-inflammatory, antinociceptive, and anxiolytic properties.p-Cymene inhibits the growth of S. typhimurium, E. coli, L. monocytogenes, S. epidermidis, and S. aureus with MIC values ranging from 0.266 to 0.608% v/v.It decreases the invasive activity of HT-1080 human fibrosarcoma cells in vitro by 87% when used at a concentration of 600 μM.In mouse hippocampus, p-Cymene (50 mg/kg, i.p.) reduces lipid peroxidation and nitrite content by 65.5 and 71.2%, respectively, and increases superoxide dismutase (SOD) and catalase activities by 22.7 and 119.3%, respectively, compared to vehicle control animals.Formulations containing p-cymene have been used as flavoring agents.
  • OccurrenceWidespread in nature; reported in the oils of cypress, Artemisia cina Bg., Ceylon cinnamon, boldo leaf, cascarilla, Cuminum cyminum L. and lemon; in the oils for seeds of coriander and Cicuta virosa; in the ether-extracted oils of Monarda fisulosa and Monarda puncata; in the star anise and nutmeg essential oils. Note that p-cymene reported in essential oil may be formed from the conversion of a cyclic terpene; its presence is indicative of aging in lemon essential oil. Reported found in citrus juices and peel oils, guava, papaya, black currant, pineapple, blueberry, blackberry, carrot, tomato, celery seed, cumin seed, mace, ginger, coriander seed, anise, nutmeg, mace, parsley, cardamom, cinnamon root and bark, pepper, peppermint oil, spearmint oil, cassia leaf and Thymus vulgaris.
  • DefinitionChEBI: A monoterpene that is toluene substituted by an isopropyl group at position 4.
  • PreparationObtained chiefly from the wash water of sulfite paper.
  • Aroma threshold valuesAroma characteristics at 1% EtoH: harsh chemical, woody and terpy-like with an oxidized citrus lemon note. It has spicy nuances reminiscent of cumin, oregano and cilantro
  • Taste threshold valuesTaste characteristics at 1 to 10 ppm: terpy and rancid with slightly woody, oxidized citrus notes. It has spice nuances of green pepper and oregano.
  • General DescriptionColorless liquid with a mild pleasant odor. Floats on water.
  • Air & Water ReactionsInsoluble in water.
  • Reactivity ProfileVigorous reactions, sometimes amounting to explosions, can result from the contact between aromatic hydrocarbons, such as CYMENE, and strong oxidizing agents. They can react exothermically with bases and with diazo compounds. Substitution at the benzene nucleus occurs by halogenation (acid catalyst), nitration, sulfonation, and the Friedel-Crafts reaction.
  • Health HazardInhalation causes impairment of coordination, headache. Contact with liquid causes mild irritation of eyes and skin. Ingestion causes irritation of mouth and stomach.
  • Fire HazardHIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
  • Chemical ReactivityReactivity with Water: No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
  • Safety ProfileMildly toxic by ingestion. Humans sustain central nervous system effects at low doses. A skin irritant. Flammable liquid. Explosion Hazard: Slight in the form of vapor. To fight fire, use foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and fumes.
  • MetabolismIn this compound both an isopropyl and a methyl group occur together and the available evidence shows that only the methyl group is oxidized, cumic acid (pisopropylbenzoic acid) and its conjugate (cuminuric acid) being the main metabolites in dogs and in sheep (Williams, 1959). Following inhalation, only a small part is excreted unchanged, the remainder being oxidized to water-soluble metabolites. As early as 1873, Ziegler suggested that the readily oxidized propyl side-chain formed a -COO H group (Browning, 1965): The ultimate product in the case of dogs and sheep is cumic acid, which is probably excreted as a conjugate with glycine (Gerarde, 1960).
  • Purification MethodsWash p-cymene with cold, conc H2SO4 until there is no further colour change, then repeatedly with H2O, 10% aqueous Na2CO3 and H2O again. Dry it over Na2SO4, CaCl2 or MgSO4, and distil it. Further purification steps include steam distillation from 3% NaOH, percolation through silica gel or activated alumina, and a preliminary reflux for several days over powdered sulfur. Store it over CaH2. [Beilstein 5 IV 1060.]
p-Cymene Preparation Products And Raw materials
p-Cymene(99-87-6)Related Product Information
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