Menthol
IUPAC name	(1R,2S,5R)-2-isopropyl- 5-methylcyclohexanol
Other names	3-p-Menthanol, Hexahydrothymol, Menthomenthol, peppermint camphor
Identifiers
CAS number	[89-78-1]
RTECS number	OT0350000, racemic
SMILES	CC1CCC(C(C1)O)C(C)C
Properties
Molecular formula	C10H20O
Molar mass	156. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to Registry of Toxic Effects of Chemical Substances ( RTECS) is a Database of Toxicity information compiled from the open scientific literature without reference A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 27 g·mol−1
Appearance	White or colorless crystalline solid
Density	0. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 890 g·cm−3, solid (racemic or (−)-isomer)
Melting point	36–38 °C (311 K), racemic 42–45 °C (318 K), (−)-form (α) 35-33-31 °C, (−)-isomer
Boiling point	212 °C (485 K)
Solubility in water	Slightly soluble, (−)-isomer
Hazards
MSDS	External MSDS
MSDS	External MSDS
Main hazards	Irritant, flammable
R-phrases	R37/38, R41
S-phrases	S26, S36
Flash point	93 °C
Related compounds
Related alcohols	Cyclohexanol, Pulegol, Dihydrocarveol, Piperitol
Related compounds	Menthone, Menthene, Thymol, p-Cymene, Citronellal
Supplementary data page
Structure and properties	n, εr, etc. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Water is a common Chemical substance that is essential for the survival of all known forms of Life. A material safety data sheet ( MSDS) is a form containing data regarding the properties of a particular substance and save the page --> This page provides supplementary chemical data on Menthol. A material safety data sheet ( MSDS) is a form containing data regarding the properties of a particular substance and save the page --> This page provides supplementary chemical data on Menthol. Occupational safety and health is a cross-disciplinary area concerned with protecting the Safety, Health and welfare of people engaged in R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. The flash point of a flammable liquid is the lowest Temperature at which it can form an ignitable mixture in air In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon Cyclohexanol is a secondary alcohol, formula C 6 H 11 OH, consisting of a Cyclohexane ring with one Hydrogen Menthone is a naturally occurring Organic compound with a molecular formula C10H18O Thymol is a Monoterpene phenol derivative of Cymene, C10H14OH Isomeric with Carvacrol, found in oil of Cymene, or p -cymene is a naturally occurring Aromatic Organic compound. Citronellal or rhodinal or 37-dimethyloct-6-en-1-al ( C 10 H 18 O) is a monoterpenoid, the main and save the page --> This page provides supplementary chemical data on Menthol. and save the page --> This page provides supplementary chemical data on Menthol. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium Measurement The relative static permittivity εr can be measured for static Electric fields as follows first the Capacitance of a test
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Menthol is an organic compound made synthetically or obtained from peppermint or other mint oils. and save the page --> This page provides supplementary chemical data on Menthol. and save the page --> This page provides supplementary chemical data on Menthol. Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry ( UV/ VIS) involves the Spectroscopy of Photons in the UV-visible Infrared spectroscopy (IR spectroscopy is the subset of Spectroscopy that deals with the Infrared region of the Electromagnetic spectrum. Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is the name given to a technique which exploits the magnetic properties of certain nuclei Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. Peppermint ( Mentha × piperita) is a hybrid mint, a cross between Watermint ( Mentha aquatica) and Spearmint Mentha ( mint) is a Genus of about 25 Species (and many hundreds of varieties) of Flowering plants in the family It is a waxy, crystalline substance, clear or white in color, which is solid at room temperature and melts slightly above. Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed The main form of menthol occurring in nature is (-)-menthol, which is assigned the (1R,2S,5R) configuration. Menthol has local anesthetic and counterirritant qualities, and it is widely used to relieve minor throat irritation. A local anesthetic is a drug that causes reversible Local anesthesia and a loss of Nociception. A counterirritant is a substance which creates Inflammation in one location with the goal of lessening the inflammation in another location

Contents 1 Structure 2 Biological properties 3 Occurrence 4 Production 5 Applications 6 Reactions 7 History 8 References 9 Further reading 10 External links

Structure

Natural menthol exists as one pure enantiomer, nearly always the (1R,2S,5R) form (bottom left of diagram below). In Chemistry, an enantiomer ( from the Greek ἐνάντιος opposite and μέρος part or portion is one of two Stereoisomers that are nonsuperimposable The other seven stereoisomers are:

In the natural compound, the isopropyl group is oriented trans- orientation to both the methyl and alcohol groups. Stereoisomers are isomeric molecules that have the same molecular formula and sequence of bonded atoms (constitution but which differ in the three dimensional orientations In Organic chemistry, isopropyl is a substituent form of Propane, the three- Carbon Alkyl Functional group. Stereochemistry, a subdiscipline of Chemistry, involves the study of the relative spatial arrangement of Atoms within Molecules An important branch In Chemistry, a methyl group is a Hydrophobic Alkyl Functional group named after Methane (4 In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon Thus it can be drawn in any of the ways shown:

In the ground state all three bulky groups in the chair are equatorial, making (-)-menthol and its enantiomer the most stable two isomers out of the eight. Cyclohexane is a Cycloalkane with the Molecular formula C 6 H 12

There are two crystal forms for racemic menthol; these have melting points of 28 °C and 38 °C. In Chemistry, a racemic mixture, or racemate, is one that has equal amounts of left- and right-handed enantiomers of a chiral Pure (-)-menthol has four crystal forms, of which the most stable is the α form, the familiar broad needles.

Biological properties

Menthol's ability to chemically trigger the cold-sensitive TRPM8 receptors in the skin is responsible for the well known cooling sensation that it provokes when inhaled, eaten, or applied to the skin. Transient receptor potential cation channel subfamily M member 8, also known as TRPM8, is a human Gene. Menthol does not cause an actual drop in temperature. ^[1] In this sense it is similar to capsaicin, the chemical responsible for the spiciness of hot peppers (which stimulates heat sensors, also without causing an actual rise in temperature). Capsaicin /ˌkæpˈseˌɪsɪn/ (8- Methyl - N - Vanillyl -6-nonen Amide) is the active component of Chili peppers

Occurrence

Mentha arvensis is the primary species of mint used to make natural menthol crystals and natural menthol flakes. Mentha arvensis ( Field Mint Wild Mint or Corn Mint) is a species of mint native to the Temperate regions of Europe Mentha ( mint) is a Genus of about 25 Species (and many hundreds of varieties) of Flowering plants in the family In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating This species is primarily grown in the Uttar Pradesh region in India. Uttar Pradesh (उत्तर प्रदेश اتر پردیش pronounced, Translation: Northern Province) referred to as '''U India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country

(-)-Menthol (also called l-menthol or (1R,2S,5R)-menthol) occurs naturally in peppermint oil (along with a little menthone, the ester menthyl acetate and other compounds), obtained from mentha x piperita. Menthone is a naturally occurring Organic compound with a molecular formula C10H18O Peppermint ( Mentha × piperita) is a hybrid mint, a cross between Watermint ( Mentha aquatica) and Spearmint Japanese menthol also contains a small percentage of the 1-epimer, (+)-neomenthol. In Chemistry, epimers are Diastereomers that differ in configuration of only one stereogenic center

Production

As with many widely-used natural products, the demand for menthol greatly exceeds the supply from natural sources. Menthol is manufactured as a single enantiomer (94% ee) by Takasago International Co. In Chemistry, an enantiomer ( from the Greek ἐνάντιος opposite and μέρος part or portion is one of two Stereoisomers that are nonsuperimposable Enantiomeric excess exists where one Enantiomer is present more than the other in a Chemical substance, and is defined as the absolute difference between the mole on a scale of 400,000 tonnes per year. This article is about the tonne or metric ton For other tons see Ton. The process involves an asymmetric synthesis developed by a team led by Ryoji Noyori:

The process begins by forming an allylic amine from myrcene, which undergoes asymmetric isomerisation in the presence of a BINAP rhodium complex to give (after hydrolysis) enantiomerically pure R-citronellal. Asymmetric synthesis, also called chiral synthesis, enantioselective synthesis or stereoselective synthesis, is Organic synthesis which (born September 3, 1938) is a Japanese chemist He won the Nobel Prize in Chemistry in 2001 An allyl group is an Alkene Hydrocarbon group with the formula H2C=CH-CH2- Myrcene, or β-myrcene is an olefinic natural Organic compound. Asymmetric synthesis, also called chiral synthesis, enantioselective synthesis or stereoselective synthesis, is Organic synthesis which In Chemistry isomerisation is the process by which one Molecule is transformed into another molecule which has exactly the same atoms but the atoms are rearranged BINAP is an Acronym for the Organophosphorus compound 22'-bis(diphenylphosphino-11'-binaphthyl Rh redirects here For other uses see Rh (disambiguation Rhodium (ˈroʊdiəm is a Chemical element with the symbol Hydrolysis is a Chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions which may go on to participate in further reactions Citronellal or rhodinal or 37-dimethyloct-6-en-1-al ( C 10 H 18 O) is a monoterpenoid, the main This is cyclised by a carbonyl-ene-reaction initiated by zinc bromide to isopulegol which is then hydrogenated to give pure (1R,2S,5R)-menthol. The Ene reaction (also known as the Alder-ene reaction) is a Chemical reaction between an Alkene with an Allylic Hydrogen (the Zinc bromide is a White Ionic solid. Uses Organic chemistry as a Lewis acid.

Racemic menthol can be prepared simply by hydrogenation of thymol, and menthol is also formed by hydrogenation of pulegone. In Chemistry, a racemic mixture, or racemate, is one that has equal amounts of left- and right-handed enantiomers of a chiral Thymol is a Monoterpene phenol derivative of Cymene, C10H14OH Isomeric with Carvacrol, found in oil of Pulegone is a naturally occurring Organic compound obtained from the Essential oils of a variety of plants such as Nepeta cataria ( Catnip

Applications

Menthol is included in many products for a variety of reasons. These include:

• In non-prescription products for short-term relief of minor sore throat and minor mouth or throat irritation
  • Examples: lip balms and cough medicines
• As an antipruritic to reduce itching
• As a topical analgesic to relieve minor aches and pains such as muscle cramps, sprains, headaches and similar conditions, alone or combined with chemicals like camphor or capsaicin. Lip balm or lip salve is a substance topically applied to the lips of the Mouth to relieve chapped or dry lips Angular cheilitis or Stomatitis A cough medicine is a medicinal drug used to treat Coughing and related conditions Antipruritics, also known as anti-itch drugs, are Medications that inhibit the Itching (Latin Pruritus) that is often associated with Sunburns } Camphor is a waxy white or transparent solid with a strong aromatic odor Capsaicin /ˌkæpˈseˌɪsɪn/ (8- Methyl - N - Vanillyl -6-nonen Amide) is the active component of Chili peppers In Europe it tends to appear as a gel or a cream, while in the US patches and body sleeves are very frequently used
  • Examples: Tiger Balm, or IcyHot patches or knee/elbow sleeves
• In decongestants for chest and sinuses (cream, patch or nose inhaler)
  • Examples: Vicks Vaporub
• In certain medications used to treat sunburns, as it provides a cooling sensation (then often associated with aloe)
• As an additive in certain cigarette brands, for flavor, to reduce the throat and sinus irritation caused by smoking and arguably to reduce the bad-breath smokers experience and possibly improve the smell of second-hand smoke. Tiger Balm ( is the trade name for a Heat rub manufactured and distributed by Haw Par Healthcare in Singapore. IcyHot is a Topical Analgesic Heat rub meant for relieving pains such as Arthritis, Backache, muscle strains Sprains, Sleeve ( O Eng ''slieve'' or ''slyf'', a word allied to slip, cf A decongestant is a broad class of Medications used to relieve Nasal congestion. Vicks is a line of over-the-counter Medications owned by the American company Procter & Gamble. A sunburn is a burn to living tissue such as Skin produced by overexposure to Ultraviolet (UV radiation commonly from the Sun 's rays Aloe, also written Aloë, is a Genus containing about four hundred Species of flowering succulent Plants A menthol cigarette is a Cigarette flavored with the compound Menthol, a substance which triggers the cold-sensitive nerves in the Skin without actually
• Commonly used in oral hygiene products and bad-breath remedies like mouthwash, toothpaste, mouth and tongue-spray, and more generally as a food flavor agent; e. Oral hygiene is the practice of keeping the Mouth and Teeth clean in order to prevent dental problems and bad breath. Mouthwash or mouth rinse is a product used for Oral hygiene. Antiseptic and anti-plaque mouth rinse claims to kill the bacterial plaque Toothpaste is a Paste or Gel Dentifrice used to clean and maintain the aesthetics and health of Teeth. g. in chewing-gum, candy
• In a soda as well as in a syrup to be mixed with water to obtain a very low alcohol drink or (brand Ricqlès in France). For songs called "Chewing Gum" see Chewing Gum (song Chewing gum is a type of Confectionery traditionally made of Chicle Candy, specifically sugar candy, is a confection made from a concentrated solution of sugar in water to which a variety of flavorings and colorants is added Soft drink is a beverage that does not contain Alcohol. Carbonated soft drinks are commonly known as soda soda pop pop, or In Cooking, a syrup (from Arabic' ar شراب sharab, beverage via Latin siropus) is a thick Viscous Liquid Ricqlès is a French Soft drink. The brand Ricqlès was created in 1838 in Uzès, France, and was originally produced as The syrup is/was also used to alleviate nausea, in particular motion sickness, by pouring a few drops on a lump of sugar. Nausea ( Latin: Nausea, Greek:, " Sea-sickness " also called wamble) is the sensation of unease and discomfort Motion sickness or kinetosis is a condition in which a disagreement exists between visually perceived movement and the Vestibular system 's sense of movement
• As a pesticide against tracheal mites of honey bees
• In perfumery, menthol is used to prepare menthyl esters to emphasize floral notes (especially rose)
• In first aid products such as "mineral ice" to produce a cooling effect as a substitute for real ice in the absence of water or electricity (Pouch, Body patch/sleeve or cream)
• In various patches ranging from fever-reducing patches applied to children's foreheads to "foot patches" to relieve numerous ailments (the latter being much more frequent and elaborate in Asia, especially Japan: some varieties use "functional protrusions", or small bumps to massage ones feet as well as soothing them and cooling them down)
• In some beauty products such as hair-conditioners, based on natural ingredients (e. Diseases of the honey bee include Pests and parasites Varroa mites See also Varroa destructor Varroa destructor and This article refers collectively to all true honey bees for the "common" domesticated honey bee see European honey bee Honey bees Perfume is a mixture of fragrant Essential oils and Aroma compounds Fixatives and Solvents used to give the human body animals objects and living For a topic outline on this subject see List of basic Japan topics. g. St. Ives)

Currently no reported nutrient or herb interactions involve menthol. It is used in Eastern medicine to treat indigestion, nausea, sore throat, diarrhea, colds, and headaches. (-)-Menthol has low toxicity: Oral (rat) LD₅₀: 3300 mg·kg⁻¹; Skin (rabbit) LD₅₀: 15800 mg·kg⁻¹). In Toxicology, the median lethal dose, LD50 (abbreviation for “Lethal Dose 50%” or LCt50 (Lethal Concentration & Time of a

In organic chemistry, menthol is used as a chiral auxiliary in asymmetric synthesis. Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation A chiral auxiliary is a Chemical compound or unit that is temporarily incorporated into an Organic synthesis so that it can be carried out asymmetrically with the Asymmetric synthesis, also called chiral synthesis, enantioselective synthesis or stereoselective synthesis, is Organic synthesis which For example, sulfinate esters made from sulfinyl chlorides and menthol can be used to make enantiomerically pure sulfoxides by reaction with organolithium reagents or Grignard reagents. Sulfinic acids are Oxoacids of Sulfur with the structure RSO(OH Esters are a class of Chemical compounds and Functional groups Esters consist of an inorganic or organic Acid in which at least In Chemistry, an enantiomer ( from the Greek ἐνάντιος opposite and μέρος part or portion is one of two Stereoisomers that are nonsuperimposable A sulfoxide is a Chemical compound containing a sulfinyl Functional group attached to two carbon atoms An organolithium reagent is an Organometallic compound with a direct bond between a Carbon and a Lithium atom The Grignard reaction, named for the French chemist François Auguste Victor Grignard, is an organometallic Chemical reaction in which Alkyl - Menthol is also used for classical resolution of chiral carboxylic acids, via the menthyl esters.

Reactions

Menthol reacts in many ways like a normal secondary alcohol. It is oxidised to menthone by oxidising agents such as chromic acid or dichromate,^[2] though under some conditions the oxidation can go further and break open the ring. Menthone is a naturally occurring Organic compound with a molecular formula C10H18O Chromic acid generally refers to a collection of compounds generated by the acidification of solutions containing Chromate and Dichromate anions or the Chromates and dichromates are Salts of Chromic acid and dichromic acid respectively Menthol is easily dehydrated to give mainly 3-menthene, by the action of 2% sulfuric acid. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. PCl₅ gives menthyl chloride. Phosphorus pentachloride is the Chemical compound with the formula PCl5

History

There is evidence^[3] that menthol has been known in Japan for more than 2000 years, but in the West it was not isolated until 1771, by Hieronymous David Gaubius. For a topic outline on this subject see List of basic Japan topics. The term Western world, the West or the Occident ( Latin: occidens -sunset -west as distinct from the Orient) can have multiple meanings ^[4] Early characterizations were done by Oppenheim,^[5] Beckett,^[6] Moriya,^[7] and Atkinson. ^[8]

References

Further reading

• E. E. Turner, M. M. Harris, Organic Chemistry, Longmans, Green & Co. , London, 1952.
• Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
• The Merck Index, 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960.
• Perfumer & Flavorist, December, 2007, Vol. 32, No. 12, Pages 38-47

External links

• Colacot T. J. Platinum Metals Review 2002, 46(2), 82-83.
• Ryoji Noyori Nobel lecture (2001)
• Menthol Information
• Cooler than Menthol
• A review of menthol from the Science Creative Quarterly

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