What are the usage, dosage and effects of menthol?

Menthol is a chemical agent. Many people do not understand menthol or its functions. The following is the usage and dosage of menthol that I have compiled for you. I hope you like it.

Usage and dosage of menthol

Oral administration: 0.02-0.1 g, usually in tablet form. External use: enter into liquor, ointment, and apply.

Main introduction of menthol

Drug name

Common name: menthol

English name: l-menthol

Ingredients: This product is a saturated cyclic alcohol obtained from mint oil.

Indications: External use for skin itching and pruritic skin diseases caused by various causes. This product is a saturated cyclic alcohol obtained from mint oil. Also known as menthol and mint ice.

Adverse reactions are not yet clear. Contraindications

Contraindicated for infants and young children.

Precautions: Do not use on eyes or mucous membranes. The lethal dose for humans is about 2 grams. It is very dangerous to use nasal drops or ointments containing this product in the nasal cavity of young children, which may cause collapse.

Medication for special groups Children. Precautions:

Contraindicated for infants and young children.

Effects and functions of menthol

1. Menthol is an ingredient extracted from the leaves of mint. Menthol can be used as toothpaste, perfume, and It can be used as a flavoring agent in some drinks and candies. Menthol can be used as a stimulant. Menthol can be used externally, which can have a cooling and antipruritic effect. At the same time, menthol can also be taken internally, which can have a carminative effect. If you have a headache, if you have a stuffy nose, or If you have a bad feeling in your throat, you can use menthol.

2. Menthol can be used to produce cooling oil. Menthol is also included in pain relievers. Some toothpastes or tooth powders also contain menthol. Menthol can be used in candies, some drinks and spices. It can relieve pain and itching. You can apply it on your temples when you have a headache or dizziness. If you have a mosquito bite, you can apply it on the bitten area. You can also apply it on the brand. It is good for colds and nasal congestion. If you have throat inflammation or If you have a bad stomach, you can take it orally. Menthol should not be given to infants and young children.

Preparation method of menthol

Industrially, steam distillation and organic solvent extraction are used to extract peppermint oil and menthol from mint. The former has low extraction efficiency and the latter contains organic solvents. Toxicity of solvent residues. Using supercritical carbon dioxide to extract menthol (menthol) from mint can eliminate the disadvantages caused by the above two methods. Its yield is about 5 times higher than the steam distillation method and about 3 times higher than the organic solvent method. The product maintains pure natural characteristics, good quality, high purity, no solvent residual toxicity, easy to meet export requirements, and has better competitiveness. , can occupy the market. Menthol can be purified from natural mint crude oil or produced synthetically. The essential oil obtained by steam distillation of the above-ground parts (stems, branches, leaves and inflorescences) of the Lamiaceae plant mint is called mint crude oil, with an oil yield of 0.5-0.6. There are many ways to synthesize bohenao.

Manufactured from citronellal

Taking advantage of the property that citronellal can easily cyclize into isopulegol, dextrorotatory citronellal is cyclized into levorotatory isopulegol using an acid catalyst (such as silica gel). From menthol, L-isopulthol is separated and hydrogenated to form L-menthol. Its stereoisomers can be partially converted into d-citronellal through thermal cracking and recycled.

Manufactured from thymol

In the presence of aluminum m-cresol, m-cresol undergoes alkylation reaction to generate thymol. After catalytic hydrogenation, all four pairs of menthol stereoisomers (i.e., racemic menthol; racemic neomenthol; racemic isomenthol and racemic neoisomenthol) are obtained. It is distilled to remove the spin-menthol fraction, and the ester is produced and then recrystallized repeatedly to separate and optically resolve the isomers. The separated L-menthol ester is saponified to obtain menthol.

Racemic menthol can be separated from the other three pairs of isomers by distillation. The remaining isomer mixture can be equilibrated into racemic menthol and racemic neomenthol under the conditions of hydrogenation of thymol. , racemic isomenthol, the ratio is 6:3:1, the content of new isomenthol is very small and can be ignored. Racemic menthol can be separated from the above mixture. Racemic menthol is inoculated and crystallized with L-ester through a saturated solution of benzoate ester or its ultra-cold mixture, separated and then saponified to obtain pure L-menthol; the unnecessary D-menthol and other isomers can be balanced according to hydrogenation conditions Converted to racemic menthol.

Manufactured from peppermint oil

Freeze peppermint oil and precipitate crystals. The crystals obtained by centrifugation are recrystallized with a low-boiling solvent to obtain pure L-menthol. The mother liquor after removing the crystallization still contains 40 to 50% menthol and a relatively large amount of menthone, which is converted into a mixture of L-menthol and D-neo-menthol after hydrogenation. More L-menthol can be obtained by partially saponifying the ester, crystallizing, distilling or making its boric acid ester and then separating the other parts of the peppermint oil.