薄荷醇（有機化合物）

薄荷醇（有機化合物）

薄荷醇 （有機化合物） 次瀏覽 | 2022.08.16 11:35:08 更新 來源 ：互聯(lián)網(wǎng) 精選百科 本文由作者推薦 薄荷醇有機化合物

薄荷醇，有機化合物，無色針狀結(jié)晶或粒狀，為薄荷和歐薄荷精油中的主要成分，以游離和酯的狀態(tài)存在。薄荷醇有8種異構(gòu)體，它們的呈香性質(zhì)各不相同，左旋薄荷醇具有薄荷香氣并有清涼的作用，消旋薄荷醇也有清涼作用，其他的異構(gòu)體無清涼作用。可用作牙膏、香水、飲料和糖果等的賦香劑。在醫(yī)藥上用作刺激藥，作用于皮膚或粘膜，有清涼止癢作用；內(nèi)服可用于頭痛及鼻、咽、喉炎癥等。薄荷醇可由天然薄荷原油提純也可用合成法制取。

中文名

薄荷腦

別名

薄荷醇

化學(xué)式

C10H20O

熔點

41-43℃

沸點

212

密度

0.890

外觀

無色透明針狀晶體

閃點

93

危險性符號

Xi

英文名

menthol

CAS號

89-78-1（DL）；15356-60-2（D）；2216-51-5（L）

摩爾質(zhì)量

156.26

溶解度（水）

微溶于水

主要危害

對皮膚以及眼睛有刺激作用以及一定的毒性

薄荷醇介紹

薄荷醇

一種萜，又稱薄荷腦。分子式CHO，左旋薄荷醇為無色透明

針狀晶體；熔點44℃ ，沸點 216.4℃，比旋光度 －48° ；微溶于水 ，溶于乙醇、乙醚 、丙酮、氯仿。 消旋薄荷醇為無色透明針狀晶體；熔點 38℃， 沸點216℃； 溶于乙醇、乙醚、丙酮、苯。薄荷醇氫化生成對烷；用鉻酸氧化或催化脫氫得薄荷酮；消旋薄荷醇可通過苯甲酸酯化法拆分。薄荷醇可從薄荷油分離得到，也可由香茅醛或百里酚制造。薄荷醇是一種重要香料。左旋薄荷醇由于其清涼效果，大量用于香煙、化妝品、牙膏、口香糖、甜食和藥物、涂擦劑[發(fā)揮局部止癢、止痛、清涼（機理：刺激皮膚上的冷感受器但不導(dǎo)致實際溫度變化）及輕微局麻等作用，也起促滲透劑作用]中。合成薄荷醇是各種異構(gòu)體的混合物，價值不大。

薄荷醇是在葉片里制造的，也就是薄荷油的主要成分，是環(huán)類單萜的一種。是植物所產(chǎn)生的高揮發(fā)性精油，其成份多為半萜、單萜及倍半萜，尤其在氣候溫暖時產(chǎn)量更高。某些重要的植物色素是類萜或含類萜基的化合物。

植物來源

唇形科植物薄荷Mentho haplocalyx Bing）全草,金錢草Glechoma longituba（Nakai）Kupr.全草,尖紫蘇Perilla frutescens （L.）Britt.var .Acuto（Thunb.）Kudo葉.

分子式及分子量

CHO,156.27 [CAS NO.]:89-78-1

[物理性質(zhì)]白色晶體

藥理作用

有止癢、止痛、防腐、刺激、麻醉、清涼和抗炎作用,可治頭痛、神經(jīng)痛、瘙癢及呼

吸道炎癥、萎縮性鼻炎、聲啞等.

[Herb source]: Mentho haplocalyx Bing

[Molecular Formula]: C10H20O,

[Molecular Weight]: 156.27

[Physics Properties]:white crystal

[Pharmacology function]: itching, pain relieving and anti-corrosion and stimulating, narcotic, cool and anti-inflammatory effects, to cure a headache, neuralgia, itching and respiratory inflammation, atrophic rhinitis, signs, etc.

檢驗

取本品葉粉末少許，經(jīng)微量升華得油狀物，迅速加硫酸2滴及香草醛結(jié)晶少量，顯黃色至橙黃色，再加水1滴，即變紫紅色。（示薄荷醇）

貯藏

：密閉、避免高溫及強氧化劑。

薄荷醇；薄荷腦；[1R-（1α,2β,5α）]-5-甲基-2-（1-甲基乙基）環(huán)己醇；薄荷冰；萜醇-；對烷-3-醇；[1R-（1A,2B,5A）]-5-甲基-2-（1-甲基乙基）；2-異丙基-5-甲基環(huán)己醇;l-menthol；（-）-menthol；（-）-menthyl alcohol；（1r,3r,4s）-（-）-menthol；（1r-（1-alpha,2-beta,5-alpha））-5-methyl-2-（1-methyl

ethyl）cyclohexanol；（l）-menthol；（r）-（-）-menthol

資料： CAS:2216-51-5

分子式: CHO

分子質(zhì)量: 156.26

沸點: 212℃

熔點: 41-43℃

中文名稱: 薄荷醇；薄荷腦；[1R-（1α,2β,5α）]-5-甲基-2-（1-甲基乙基）環(huán)己醇；薄荷冰；萜醇-；對烷-3-醇；[1R-（1A,2B,5A）]-5-甲基-2-（1-甲基乙基）；2-異丙基-5-甲基環(huán)己醇

英文名稱: l-menthol；（-）-menthol；（-）-menthyl alcohol；（1r,3r,4s）-（-）-menthol；（1r-（1-alpha,2-beta,5-alpha））-5-methyl-2-（1-methylethyl）cyclohexanol；（l）-menthol；（r）-（-）-menthol

性質(zhì)

無色針狀結(jié)晶或粒狀。熔點41-43℃（42-45℃），沸點216.5℃，相對密度0.890（15/15℃），折光率1.458。易溶于醇；氯仿；醚；冰醋酸；液狀石蠟及石油醚，微溶于水。薄荷醇含有三個不對稱碳原子，已知四個空間順式和反式異構(gòu)體，它們每個都有右旋型；左旋型以及消旋型。左旋薄荷醇具有特征有薄荷香氣并有清涼的作用。消旋薄荷醇（[89-78-1]）也有清涼作用，其它的異構(gòu)體無清涼作用。[2]

生產(chǎn)

薄荷醇可由天然薄荷原油提純也可用合成法制取。唇形科植物薄荷的地上部分（莖；枝；葉和花序）經(jīng)水蒸氣蒸餾所得的精油稱薄荷原油，得油率為0.5-0.6。合成薄合腦的方法有多種。1.從香茅醛中制造 利用香茅醛易環(huán)化成異胡薄荷醇的性質(zhì)，將右旋香茅醛用酸催化劑（如硅膠）環(huán)化成左旋異胡薄荷醇，分出左旋異胡薄荷醇，氫化生成左旋薄荷。其立體導(dǎo)師構(gòu)體經(jīng)熱裂解可部分地遭到轉(zhuǎn)變成右旋香茅醛，再循環(huán)使用。2.從百里酚中制造 在間甲酚鋁存在，對間甲酚進行烷基化反應(yīng)生成百里酚。經(jīng)催化加氫得所有四對薄荷醇立體異構(gòu)體（即消旋薄荷醇；消旋新薄荷醇；消旋異薄荷醇和消旋新異薄荷醇）。將其進行蒸餾，取消旋薄荷醇餾分，制造酯后反復(fù)重結(jié)晶，進行異構(gòu)體的分離和光學(xué)拆分。分離出來的左旋薄荷醇酯，經(jīng)皂化后得薄荷腦。

薄荷醇是一種重要的香料，有多種生產(chǎn)方法：

①從薄荷油制造：將薄荷油冷凍后析出結(jié)晶，離心所得結(jié)晶用低沸溶劑重結(jié)晶得純左旋薄荷醇。除去結(jié)晶后的母液仍含薄荷醇40%～50%，還含較大量的薄荷酮，經(jīng)氫化轉(zhuǎn)變?yōu)樽笮『纱己陀倚卤『纱嫉幕旌衔铩Ⅴサ牟糠衷砘?jīng)結(jié)晶、蒸餾或制成其硼酸酯后分去薄荷油中的其他部分，可得到更多的左旋薄荷醇。

②從香茅醛制造：利用香茅醛易環(huán)化成異胡薄荷醇的性質(zhì)，將右旋香茅醛用酸催化劑（如硅膠）環(huán)化成左旋異胡薄荷醇，分出左旋異胡薄荷醇，氫化生成左旋薄荷醇。其立體異構(gòu)體經(jīng)熱裂解可部分再轉(zhuǎn)變成右旋香茅醛，再循環(huán)使用。

③從百里酚制造：百里酚氫化得所有四對薄荷醇立體異構(gòu)體

應(yīng)用常見應(yīng)用

薄荷腦和消旋薄荷腦均可用作牙膏、香水、飲料和糖果等的賦香劑。在醫(yī)藥上用作刺激藥，作用于皮膚或粘膜，有清涼止癢作用；內(nèi)服可用于頭痛及鼻、咽、喉炎癥等。其酯用于香料和藥物。在世界上，我國和巴西是主要的天然薄荷生產(chǎn)國，薄荷油的年產(chǎn)量均達到2000-3000t。

“清涼衛(wèi)生巾”及其健康爭論

一些衛(wèi)生巾品牌將薄荷醇等物質(zhì)應(yīng)用于衛(wèi)生巾表面，開發(fā)出“清涼衛(wèi)生巾”品種。利用此類物質(zhì)的特性產(chǎn)生“清涼”感。但需要注意的是，敏感皮膚和過敏體質(zhì)的女性，應(yīng)當(dāng)慎用添加香料和藥物成分的衛(wèi)生巾，以免引起皮膚刺激和過敏反應(yīng)。

針對“清涼衛(wèi)生巾”，有流言稱其“破壞生殖器的弱酸環(huán)境，弱酸環(huán)境的破壞會使生殖器自身的抵抗能力下降！用了會讓月經(jīng)量越來越少”。但這一說法并不可靠。原因包括：

1，“清涼衛(wèi)生巾”破壞陰道弱酸環(huán)境的說法在理論上有可能成立，但實際中可能較小。陰道的微生態(tài)環(huán)境的平衡對外界微生物的侵入有一定防御功能，稱為陰道的自凈作用。雌激素、陰道乳桿菌和陰道的弱酸性環(huán)境是構(gòu)成陰道自凈能力的三個重要環(huán)節(jié)。對薄荷醇的研究表明，薄荷醇本身具有一定抑菌能力，理論上在一定用量之下可能導(dǎo)致陰道弱酸性環(huán)境的破壞。但在實際情況中，產(chǎn)生涼感所需的薄荷醇濃度遠小于其最低抑菌濃度，局部使用并實際進入陰道的薄荷醇難以產(chǎn)生抑菌效果。

2，“清涼衛(wèi)生巾”也不會讓月經(jīng)量越來越少。首先薄荷醇并沒有性激素的藥理作用，不會影響內(nèi)分泌，也就不會對月經(jīng)產(chǎn)生影響。其次，子宮和陰道是相對隔離的兩個環(huán)境，只在經(jīng)期宮頸口會微微打開以便排出宮腔內(nèi)產(chǎn)生的月經(jīng)。因此能夠從衛(wèi)生巾表面擴散進入宮腔的薄荷醇等化學(xué)物質(zhì)微乎其微，不可能對宮內(nèi)環(huán)境造成影響。

此外，包括“清涼衛(wèi)生巾”在內(nèi)的一些所謂的草本衛(wèi)生巾會宣傳對女性有某些保健和治療作用，這一點也不可輕信。一方面，并沒有可靠的證據(jù)表明這些宣傳的功效是實際有效的；另一方面，由于皮膚的結(jié)構(gòu)致密，藥物吸收有限，就算是在其他方面證明有效的藥物，也不代表用在衛(wèi)生巾上同樣有效。

注意

由于本品對皮膚以及眼睛有刺激作用以及一定的毒性，大量使用時必須戴好手套以及安全眼鏡。

[中毒急救措施]

1、吸入：將中毒著轉(zhuǎn)移至通風(fēng)處，采取一般急救措施。

2、誤入眼睛：按一般步驟沖洗眼睛，有必要著請咨詢醫(yī)師。

3、皮膚接觸：用清水和肥皂清洗。

4、其他：咨詢醫(yī)師。

消旋薄荷醇可用蒸餾法與其他三對異構(gòu)體分開，剩下的異構(gòu)體混合物在百里酚氫化條件下可平衡成消旋薄荷醇、消旋新薄荷醇、消旋異薄荷醇，比例為 6:3:1，新異薄荷醇含量很少，可不計。從以上混合物可再分出消旋薄荷醇。消旋薄荷醇經(jīng)苯甲酸酯飽和溶液或其超冷混合物以左旋酯接種結(jié)晶，分開后皂化，得純左旋薄荷醇；不要的右旋薄荷醇及其他異構(gòu)體，可再按氫化條件平衡轉(zhuǎn)變?yōu)橄『纱肌?/p>相關(guān)外文文獻

下列為食品伙伴網(wǎng)上的關(guān)于薄荷醇（menthol）的英語資料。

Menthol is a terpenoid, found in the esntial oils of the mint family （Mentha spp）, such as peppermint, spearmint and others. Menthol （C10H20O） is solid at room temperature, forming long crystals that have a fatty touch. Several isomers of menthol exist, some with a menthol smell, others without. Normally occurring menthol, with the strongest smell, is （-）-menthol （lower left in figure below）.

Structure of menthol and isomers

Menthol is not or poorly soluble in water, but readily soluble in alcohol or oils.

Besides the u as an aroma in many different food products （especially dental products, such as chewing gum, cough drops and confectionary, such as mints）, menthol is contained in non-prescription products for short-term relief of minor sore throat and minor mouth or throat irritation, for example in lip balms and cough medicines. It is clasd as an antipruritic, which reduces itching. Menthol is also contained in combination products ud for relief of muscle aches, sprains, and similar conditions, as well as in decongestants. In addition, it is ud as an additive in certain cigarette brands, both for flavour and to reduce the throat and sinus irritation caud by smoking. Menthol also is a common ingredient in mouthwash.

Menthol

From Wikipedia, the free encyclopedia

Jump to: navigation, arch

Not to be confud with methanol.

Menthol

General

Systematic name 2-（2-Propyl）-5-

methylcyclohexanol

Stereochemical

configuration （2S,5R,1R）

Other names 3-p-Menthanol,

Hexahydrothymol,

Menthomenthol,

peppermint camphor

Molecular formula C10H20O

SMILES CC1CCC（C（C1）O）C（C）C

Molar mass 156.27?g·mol?1

Appearance White or colorless

crystalline solid

CAS number [89-78-1], racemic

[2216-51-5], （?）-isomer

Properties

Density and pha 0.890?g·cm?3, solid

（racemic or （?）-isomer）

Solubility in water Slightly soluble, （?）-isomer

In ethanol, diethyl ether,

acetone, chloroform

acetic acid, hexane Soluble

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）

Chiral rotation [α]D -50° at 18 °C, 10% in EtOH

Hazards

MSDS External MSDS

Main hazards Irritant, flammable

NFPA 704 210

Flash point 93?°C

R/S statement R37/38, R41 S26, S36

RTECS number OT0350000, racemic

OT0700000, （?）-enantiomer

Supplementary data page

Structure & properties n, εr, etc.

Thermodynamic data Pha behavior

Solid, liquid, gas

Spectral data UV, IR, NMR, MS

Related compounds

Related alcohols Cyclohexanol, Pulegol,

Dihydrocarveol, Piperitol

Related compounds Menthone, Menthene,

Thymol, p-Cymene,

Citronellal

Except where noted otherwi, data are given for

materials in their standard state （at 25?°C, 100?kPa）

Infobox disclaimer and references

Menthol is a covalent organic compound made synthetically or obtained from peppermint or other mint oils. It is a waxy, crystalline substance, clear or white in color, which is solid at room temperature and melts slightly above. 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 ud to relieve minor throat irritation.

Contents [hide]

1 History and occurrence

2 Structure

3 Applications

4 Synthesis

5 Natural menthol

6 Chemical properties

7 Biological properties

8 Notes

9 References

History and occurrence

There is evidence that menthol has been known in Japan for more than 2000 years, but in the West it was not isolated until 1771, by Gambius. （-）-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. Japane menthol also contains a small percentage of the 1-epimer, （+）-neomenthol.

Structure

Natural menthol exists as one pure enantiomer, nearly always the （1R,2S,5R） form （bottom left of diagram below）.

In the natural compound, the isopropyl group is oriented trans- orientation to both the methyl and alcohol groups.

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.

There are two crystal forms for racemic menthol; the have melting points of 28?°C and 38?°C. Pure （-）-menthol has four crystal forms, of which the most stable is the α form, the familiar broad needles.

Applications

Menthol is included in many products for a variety of reasons. The 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 products like Camphor or Capsaicin. In Europe it tends to appear as a gel or a cream, while in the US patches and body sleeves are very frequently ud

Examples: Tiger Balm IcyHot patches or knee/elbow sleeves

In decongestants for chest and sinus （cream, patch or no inhaler）

Examples: Vicks Vaporub

In certain medications ud to treat sunburns, as it provides a cooling nsation （then often associated with Aloe）

As an additive in certain cigarette brands, for flavor, to reduce the throat and sinus irritation caud by smoking and arguably to reduce the bad-breath smokers experience and possibly improve the smell of cond-hand smoke.

Commonly ud in oral hygiene products and bad-breath remedies like mouthwash, toothpaste, mouth and tongue-spray, and more generally as a food flavor agent e.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 Riclès in France）. The syrup is/was also ud to alleviate naua, in particular motion sickness, by pouring a few drops on a lump of sugar.

As a pesticide against tracheal mites of honeybees

In perfumery, menthol is ud to prepare menthyl esters to emphasi floral notes （especially ro）

In first aid products such as "mineral ice" to produce a cooling effect as a substitute for real ice in the abnce 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, esp. Japan: some variety u `functional protrusion' i.e. small bumps to massage ones feet as well as soothing them and cooling them down）

In some beauty products such as hair-conditioners, bad on natural ingredients （ex: St Ives）

Some supporters of the homeopathic theory of pharmacology believe that menthol interferes with the effects of homeopathic remedies. Its u is strongly discouraged for tho eking homeopathic cures, to the point of prohibiting the u of mint-flavored toothpaste. Currently no other reported nutrient or herb interactions involve menthol. It is ud in Eastern medicine to treat indigestion, naua, 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 organic chemistry, menthol is ud as a chiral auxiliary in asymmetric synthesis. For example, sulfinate esters made from sulfinyl chlorides and menthol can be ud to make enantiomerically pure sulfoxides by reaction with organolithium reagents or Grignard reagents. Menthol is also ud for classical resolution of chiral carboxylic acids, via the menthyl esters.

Synthesis

As with many widely-ud 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. on a scale of 400?000 tonnes per year. 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 prence of a BINAP rhodium complex to give （after hydrolysis） enantiomerically pure R-citronellal. This is cyclid by a carbonyl-ene-reaction initiated by zinc bromide to isopulegol which is then hydrogenated to give pure （1R,2S,5R）-menthol.

Racemic menthol can be prepared simply by hydrogenation of thymol, and menthol is also formed by hydrogenation of pulegone. For preparation of other isomers such as neomenthol, e ref. 1.

Natural menthol

Mentha arvensis is the primary species of mint ud to make natural menthol crystals and natural menthol flakes. This species is primarily grown in the Uttar Pradesh region in India.

Chemical properties

Menthol reacts in many ways like a normal condary alcohol. It is oxidid to menthone by oxidising agents such as chromic acid, though under some conditions the oxidation can go further and break open the ring. Menthol is easily dehydrated to give mainly 3-menthene, by the action of 2% sulfuric acid. PCl5 gives menthyl chloride.

Biological properties

Menthol's ability to chemically trigger cold-nsitive receptors in the skin is responsible for the well known cooling nsation that it provokes when inhaled, eaten, or applied to the skin. Menthol does not cau an actual drop in temperature. In this n it is similar to capsaicin, the chemical responsible for the spiciness of hot peppers （which stimulates heat nsors, also without causing actual temperature ri）.

Notes

^ J. L. Simonn, The Terpenes Volume I （2nd edition）, Cambridge University Press, 1947, p230-249.

^ Adversoriorum varii argumentii, Liber unus, Leiden, 1771, p99.

^ R. Eccles, Menthol and Related Cooling Compounds, Journal of Pharm. Pharmacol. 1994 46: 618-630

References

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 Jery, USA, 1960.

參考資料