Acetic aldehyde. Physical and thermal properties. Obtaining and applying

Acetic aldehyde (other names: acetaldehyde, methylformaldehyde, ethanol) is an organic compound belonging to the class of aldehydes. This substance is important for humans, it is found in coffee, bread, ripe fruits and vegetables. It is synthesized by plants. Occurs in nature and is produced in large quantities by man. The formula of acetic aldehyde: CH3-CHO.

Physical properties

1. Acetic aldehyde is a liquid without color, which has a sharp unpleasant odor.
2. It dissolves well in ether, alcohol and water.
3. The molar mass is 44.05 grams / mole.
4. The density is 0.7 grams / centimeter³.

Thermal properties

1. The melting point is -123 degrees.
2. The boiling point is 20 degrees.
3. The ignition temperature is -39 degrees.
4. The autoignition temperature is 185 degrees.

Preparation of acetic aldehyde

1. The main way of obtaining this substance is to oxidize ethylene (the so-called Wacker process). So this reaction looks like:
2CH2 = C2H4 (ethylene) + O2 (oxygen) = 2CH3CHO (methylformaldehyde)

2. Also, acetic aldehyde can be obtained by hydrating acetylene in the presence of mercury salts (the so-called Kucherov reaction). This produces phenol, which then is isomerized to the aldehyde.

3. The following method was popular before the appearance of the above process. It was carried out by oxidation or dehydrogenation of ethyl alcohol on a silver or copper catalyst.

The use of acetic aldehyde

- To get what substances do you need acetic aldehyde? Acetic acid, butadiene, aldehyde polymers and some other organic substances.
- It is used as a precursor (a substance that participates in the reaction leading to the creation of the target substance) to acetic acid. However, the use of the substance considered by us soon ceased. This happened for the reason that acetic acid is easier and cheaper to produce from the metal using the processes of Kativa and Monsanto.
- Methylformaldehyde is an important precursor to pentaerythritol, pyridine derivatives and crotonaldehyde.
- The preparation of resins as a result of the fact that urea and acetic aldehyde have the ability to condense.
- Preparation of ethylidene diacetate, from which polyvinyl acetate (vinyl acetate) monomer is subsequently produced.

Tobacco dependence and acetic aldehyde

This substance is a significant part of tobacco smoke. A recent demonstration has shown that the synergistic link between acetic acid and nicotine increases the manifestation of dependence (especially in persons under thirty).

Alzheimer's disease and acetic aldehyde

Those people who do not have a genetic factor for converting methylformaldehyde to acetic acid have a high risk of susceptibility to a disease such as senile dementia (or Alzheimer's disease), which usually occurs in old age.

Alcohol and methylformaldehyde

Presumably, the substance we are considering is a carcinogen for humans, since to date there is evidence of the carcinogenicity of acetic aldehyde in various animal experiments. In addition, methylformaldehyde damages DNA, causing a disproportionate development of the muscular system, which is associated with a violation of protein metabolism in the body. A study of 800 alcoholics was conducted, as a result of which scientists came to the conclusion that people exposed to acetic aldehyde have a defect in the gene of one enzyme - alcohol dehydrogenase. For this reason, such patients are more likely to develop cancerous kidney and upper liver disease.

Security

This substance is toxic. It is an air pollutant when smoking or from exhausts in traffic jams.