L-Menthol

Chinese Name: L- menthol

English Name: L-Menthol

The alias name: L- menthol natural menthol menthol (left)

More: alcohol Natural menthol Menthol alias L-Meng (L)

The molecular formula: C10H20O

Molecular weight: 156.27

CAS number: 2216-51-5

MDL number: MFCD00062979

EINECS number: 218-690-9

RTECS number: OT0700000

BRN number: 1902293

PubChem number: 24882791

Characters: white needle crystal with cool mint aromas.

Density (g/mL, 20oC): 0.89

The melting point (oC): 43-45

Boiling point (oC, atmospheric pressure): 103-104

The refractive index (nD20): 1.46

Flash point (oF): 200

Specific rotation (589nm, c=10, EtOH): -51 o

Point of ignition or ignition temperature (oC): 91

Solubility: soluble in alcohol; chloroform; ether; acetic acid; liquid paraffin and petroleum ether, slightly soluble in water

Synthesis method:

Menthol mint oil purification from natural or synthetic method. Mint Labiatae plant aboveground part (stems; branches; leaves and inflorescence) obtained by steam distillation from the essential oils known crude mint oil, oil production rate is 0.5-0.6.

There are several methods of synthesis of thin and brain.

1 from citronellal manufacturing easy ring into different properties of isopulegol by citronellal, citronellal to dextral using an acid catalyst (such as silica gel) cyclizes sinistral isopulegol, separate the left-hand isopulegol, hydrogenation of l-menthol. The three-dimensional structure by thermal cracking of tutor can partially was transformed into dextral citronellal, recycling use.

2 from the thymol in manufacturing presence in m-cresol aluminum, m-cresol was on the alkylation reaction of thymol. By catalytic hydrogenation of all four stereoisomers of menthol (i.e. racemic menthol; racemic new menthol; racemic isomenthol and racemic neoisomenthol). The distillation, cancel the rotary menthol ester fraction, manufacturing after repeated re crystallization, separation and optical resolution of isomers. L menthol ester is separated, by saponification after menthol.

Use:

Menthol and racemic menthol can all be used as a toothpaste; perfume; aromatizing agent drinks and candy etc.. Used as a stimulant drug in medicine, applied to the skin or mucous membrane, have cool and refreshing and antipruritic effect; oral administration can be used as a carminative, used for headache and nasal; pharynx; laryngitis etc.. The ester used in perfumes and drugs.