Methanol

Methanol . It is the main component of dry distillate from wood . It is one of the most universal solvents and finds application, both in the industrial field and in various household products.

Summary

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  • 1 Features
    • 1 Properties
  • 2 uses
  • 3 Dangers
    • 1 Toxicokinetics
    • 2 Pathophysiology
    • 3 Complications
  • 4 Sources

characteristics

Methanol can be found in so-called burning alcohol , consisting of methyl and ethyl alcohols. It can also be found in solvents in varnishes, shoe dyes, glass cleaners, antifreeze liquids, lacquer solvents, etc. In addition, packaged solid fuels also contain methanol. It is also known as wood alcohol because it was formerly obtained from the dry distillation of wood.

Properties

  • Ethanol-like odor and taste .

Applications

  • Chemical synthesis.
  • Industrial solvent.
  • Industry the plastic.
  • Leather tanning.

Dangers

This alcohol is used to degrade ethyl alcohol solutions, which has led to numerous massive poisonings due to the fraudulent use of these mixtures in alcoholic beverages. In the case of exposure to methanol in work environments, it can cause serious and even fatal poisonings. Victims of methanol who survive do so with important sequelae, such as irreversible blindness . In this case, the retina is the site of manifestation of methanol toxicity.

Methanol poisoning frequently occurs in three ways:

  • Digestive route, in the case of alcoholic beveragesadulterated with denatured alcohol.
  • Dermally (through the skin), it can hardly lead to acute poisoning.

The problem is often posed in the form of chronic poisoning. Its irritating nature generates frequent entry injuries, very typical in chronic respiratory contamination, such as chronic bronchitis , frequently with asthmatic components, and alterations in the mucosa of the upper respiratory tract. This absorption route is typical of workplaces.

Methanol is rapidly distributed in the tissues according to their aqueous content. The volume of distribution is 0.6 l / Kg of weight. Most of the methanol circulates in the plasma water . Once absorbed, it goes to the liver where it undergoes oxidation processes at a 7 times lower speed compared to that of ethyl alcohol or ethanol . The enzyme responsible for its transformation is alcohol dehydrogenase, which oxidizes it to formaldehyde and this in turn is oxidized to formic acid by aldehyde dehydrogenase.

Elimination is carried out slowly by the respiratory route through the lungs , and can remain in the body for up to 4 days after a single dose. About 3 to 5% is eliminated without metabolizing.

Toxicokinetics

  • Absorption: Gastrointestinal rapid; skin and lungs .
  • Distribution volume: 0.6-0.7 L / Kg.
  • Average Life: 14-20 h in moderate 24-30 h in severe. 30-35 h with ethanol treatment .
  • Biotransformation: It is metabolized in the liver .
  • Elimination: Liver 90 – 95%, kidney 2-5%, lung 2-5%

Alcohol dehydrogenase oxidizes methanol into formaldehyde, which is rapidly converted by aldehyde dehydrogenase to formic acid. The folic acid dependent pathway oxidizes formic acid to carbon dioxide and water .

Pathophysiology

  • Toxicity results from the accumulation of two metabolites: formaldehyde and formic acid. The accumulation of formic acid produces most of the metabolic acidosis.
  • Lactate appears late as a result of inhibition of mitochondrial respiration, which produces tissue hypoxia and stimulates anaerobic glycolysis.

Complications

  • Metabolic acidosis.
  • Lactic acidosis.
  • Kidney failure.
  • Acute
  • Loss of vision.
  • Respiratory insufficiency.
  • Cerebral edema.
  • Convulsions.

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