Methanol: Definition, Formula & Effect

Properties of methanol

Methanol is lighter than water, evaporates easily, and dissolves well in water and ethanol. It does not mix well with fats and oils. Methanol melts at -98 °C and boils at 64.5 °C and tastes burning. When mixed with air, methanol can form an ignitable mixture. This is flammable at 450 °C. Methanol contains a hydroxyl group (-OH) as a functional group.

Methanol structural formula

Figure 1: Structural formula of methanol Source: wikipedia.de

the molecular formula of methanol is.

the general formula for alcohols is .

Production of methanol

Almost 100 years ago, methanol was just passing through dry distillation of wood won. Nowadays, methanol can also be made out synthesis gas be obtained in a reactor. The synthesis gas can be obtained from natural gas or from coal. Starting materials are synthesis gas with carbon monoxide and hydrogen. Methanol is the reaction product.

Synthesis of methanol

Reacting methane gas with water produces carbon monoxide and hydrogen. This reaction is catalyzed with the help of an accelerator:

Thus, methanol can form:

Methanol is formed from carbon monoxide and hydrogen. The reaction is exothermic, so energy is released.

Use of methanol

There are many uses for methanol. For the most part, methanol is used in the chemical industry used. However, methyl alcohol is also used in laboratories, in the oil industry and in everyday life. It is mainly used as a solvent and as an intermediate in syntheses.

methanol in chemistry

Methanol is an important starting material for syntheses in the chemical industry. For example, it is oxidized to formaldehyde. Acetic acid can also be produced from methanol and carbon monoxide. Methyl alcohol also contributes to the production of methylamines. Methylamines are important precursors for medicines and pesticides.

methyl alcohol as a fuel

To generate electrical energy, methanol can be used in a Direct Methanol Fuel Cell (DMFC) be used. biodiesel is obtained by esterification of methanol with rapeseed oil. Previously, methanol was considered rocket fuel deployed.

Other Uses of Methyl Alcohol

methanol poisoning

Ingestion or prolonged contact with methanol can cause blindness or death. Methyl alcohol can penetrate the skin. Inhaling the vapors of the methanol is «less dangerous» in comparison. Most people get poisoned by ingesting methanol by mouth. Deaths have been reported after ingestion of as little as 5 mL.

the lethal dose of the methanol is estimated at about 20–70 mL. The lethal dose depends on body weight. the high toxicity can be explained by the fact that methanol cannot be completely oxidized in the organism. It becomes the toxic substances formaldehyde and formic acidtransformed.

causes

After absorption in the liver, methanol is converted by enzymes into formic acid and formaldehyde. The enzymes involved are alcohol dehydrogenase and aldehyde dehydrogenase.

Formic acid and formaldehyde are slowly eliminated and excreted through the kidneys. This is how the toxic substances accumulate in the body. Formaldehyde has a damaging effect on the adjacent organs. Formic acid leads to a metabolic acidification (acidosis). Blood pH drops below 7.35 as protons increase in the body.

signs of intoxication

In the long run one can methanol poisoning lead to vision problems, hearing problems and heart failure. It can also cause immune system disorders.

physiological effect

After absorption, methanol damages the central nervous system. The optic nerves are particularly affected and blindness can occur. With a delay, however, the liver, heart, kidneys and other organs are also damaged.

Treatment of methanol poisoning

Usually only one gastric lavage carried out. Poisoning can also be caused by the oral ingestion of ethanol to be inhibited.

Ingesting ethanol interrupts the metabolism of methanol. Some alkalizing substances, such as sodium bicarbonate, are given to counteract acidosis. Once the pH in the blood has returned to normal, the breakdown of formic acid can be accelerated. This reduces toxicity.

In some cases, when over 100 mL of methanol has been ingested, a hemodialysis necessary. Thus, the methanol and its metabolites are eliminated.

direct methanol fuel cell

the direct methanol fuel cell (English: Direct Methanol Fuel Cell, DMFC) is a low-temperature fuel cell that uses methanol (methanol-water mixture) as fuel. This happens at low cell temperatures of 60 to 120 °C.

Karl Kordesch and A. Marko first proposed the principle in 1951 at the University of Vienna. They considered other alcohols or aldehydes as fuels.

principle

One serves as the electrolyte proton conducting membrane. This will happen at the anode methanol-water mixture split into hydrogen and carbon dioxide. The carbon dioxide is mixed with the anode taken away. The anode is always surrounded by the mixture. Water is formed at the cathode.

function one DMFC-Fuel cell

Figure 2: Direct methanol fuel cell (DMFC)Source: Tuvsud.com

1. The fuel cell will two circuits Cut. The gases involved migrate from the gas space into the catalyst. oxygen moves to the cathode and methanol and water to the anode.

2. The methanol reacts with the water to form carbon dioxide and hydrogen. The hydrogen is split into two atoms (protons) by the catalyst. So every hydrogen atom has to lose its electron.

3. The protons migrate through the electrolyte (proton-conducting membrane) to the cathode.

4. The electrons move from the anode to the cathode. This causes an electric current to flow. A consumer supplies the current flow electrical energy.

5. Four electrons recombine with one oxygen molecule at the cathode.

6. The oxygen ions created from 5. are negatively charged. They react with the protons to form water.

application

Preferably, the fuel cell is carried in small portable systems. These weigh little and therefore have a high electrical output. the DMFC can supply power continuously as long as methanol is supplied.

Indirect methanol fuel cell

the indirect methanol fuel cell (English: Reformed Methanol Fuel Cell, RMFC) is a proton exchange fuel cell. Here, methanol is converted before being implemented into the fuel cell.

In comparison to DMFC Offer RMFC-Systems several advantages:

• systems with higher efficiency,

• smaller cell stacks,

• lower requirements for methanol purity,

• no water management necessary,

• better operation at low temperatures.

Since this is not a methanol-water mixture, the fuel cell can be stored at sub-zero temperatures.