Formic aldehyde, or formaldehyde, is a colorless gas with a sharp, unpleasant, specific odor. It is highly soluble in water and also in alcohols. Formaldehyde is very toxic and can cause pathological changes in the human body. In addition, it is considered a carcinogen.
Formaldehyde is the first member of a whole homologous series, which includes aliphatic formic aldehyde. Formic acid also exhibits the properties of this group.
Chemical properties
Formaldehyde is able to enter into all reactions that are characteristic of the homologous series of aliphatic aldehydes. including nucleophiles. It also binds to reducing reagents. This is mainly due to the fact that formaldehyde has a low electron density on carbon atoms. Due to this structural feature, it very easily enters into chemical reactions even with the weakest nucleophiles. This explains the fact that in aqueous solutions formic aldehyde is found in hydratedcondition.
Production receipt
This substance has a fairly simple formula. Formic aldehyde in chemical language looks like this: HCHO. The main industrial method for its production is the oxidation of methanol. This reaction is carried out using a silver catalyst. The required temperature is 650 degrees. Methanol oxidation occurs at atmospheric pressure.
This technological process has been used everywhere for quite a long time. He is well trained. Approximately 80% of formaldehyde is produced by the oxidative reaction of methanol. However, this is not the only way. An even more promising method has recently been developed. It is based on the use of iron-molybdenum catalysts. In this case, the required temperature level is reduced to 300 degrees, which is almost half as much.
Another industrial method is also known - the oxidation of methane. This reaction has a rather simple formula: formic aldehyde is obtained at a pressure of 1-2 MPa at a temperature of 450 degrees. Aluminum phosphate is taken as a catalyst.
Application
Methanediol is an aqueous solution of formaldehyde that causes protein denaturation. This quality makes it possible to use this substance as a tanning agent in the production of leather items. He also found wide application in the manufacture of film. Because of its strong tannic properties, formaldehyde is known as an antiseptic. It is widely used in medicine. On hisbasis produce such antiseptic preparations as "Formagel" and "Formidron". For quite a long time, formic aldehyde has been used in biology to store biomaterials, such as organs or animal corpses.
At present, obtaining formic aldehyde is beneficial for the woodworking and, of course, the furniture industry. It is used for the production of melamine urea-formaldehyde resins. They are used in the manufacture of chipboard, plywood and other building materials.
When storing formic aldehyde, it should be borne in mind that at temperatures below 10 degrees, the solution becomes cloudy and a white precipitate appears. Formaldehyde also interacts with oxygen. As a result, additional chain initiators are formed due to degenerate branching.
Toxic properties
So, formaldehyde is produced by the oxidation of methanol and methane. Undoubtedly, it has a fairly high degree of toxicity. Formic aldehyde primarily affects the genetic material. The reproductive organs also suffer from this substance. But, of course, damage to the respiratory tract, skin and mucous membranes of the eyes is more often noted.
Formaldehyde is also dangerous because it has a negative effect on the central nervous system.
Formic aldehyde is not just toxic - 60-90 ml of the substance (depending on body weight) ingested will cause death. The symptoms of poisoning are as follows:
- general breakdown;
- pallor of the skin;
- unconscious;
- CNS depression;
- shortness of breath;
- severe headache;
- convulsions, especially at night.
The effect of formic aldehyde on the human body
The use of formic aldehyde in production often causes varying degrees of poisoning among employees of the enterprise. With a strong inhalation lesion, that is, when a substance is inhaled, conjunctivitis and an acute form of bronchitis are observed, which sometimes leads to pulmonary edema. Symptoms with prolonged exposure to formaldehyde will only increase. After a short time, signs of damage and depression of the central nervous system will appear. This will be expressed in constant dizziness, there will be a feeling of fear, the gait will become shaky, and at night the person may even have convulsions.
If the poisoning occurred through the mouth, then the first symptom will be a burn of the mucous membrane of the digestive tract. It will manifest itself in the form of pain, burning in the throat and along the esophagus. A person feels strong vomiting, the mass rejected by the stomach will contain blood. In severe cases, laryngeal edema develops and reflex respiratory arrest occurs.
In chronic poisoning at low concentrations, a person has severe weight loss, mental agitation, visual disturbances, insomnia and persistent headaches.
Formaldehyde vapor poisoning
Formic aldehyde is most commonly found in the air. Employeesenterprises engaged in work related to the manufacture of artificial resins, in the presence of constant and prolonged contact with formaldehyde vapors, poisoning is possible. Often, already in the first working days, a person develops noticeable dermatitis on the face and hands. The presence of formaldehyde in the body can be seen in the deterioration of the condition of the nails - they soften and become brittle.
Eczema and dermatitis can be allergic. After a person has suffered poisoning, he develops a strong sensitivity to formic aldehyde. There is evidence that formaldehyde adversely affects the functioning of the female reproductive system.
Use of formaldehyde in cosmetics
Formaldehyde content is allowed as a preservative in cosmetics, but its concentration should not exceed 0.1%. Formic aldehyde may be present in toothpaste, body, face and hand creams.
Also in pharmacology, some products that prevent excessive sweating may contain formaldehyde. Its admissible concentration - 0, 5%. This substance is a good antiseptic, even in such small quantities it is able to destroy microorganisms. It is strictly forbidden to apply any ointment to the face if it contains 5% formaldehyde. This is fraught with the appearance of dermatitis and allergic reactions. Also, formic aldehyde is not used to preserve cosmetics if they are sold as aerosols and sprays.
Allproducts on their label must contain information regarding the content of this hazardous substance, even if its amount is 0.05%. In fact, to this day it has not been clarified how the formaldehyde solution affects the skin, but it is known that in animals it reddens and flakes.
Carcinogenicity of formic aldehyde
It is known that formaldehyde interacts with selenium with the participation of highly concentrated sulfuric acid. As a result, sulfoether-4-tetradecyldioxane is formed. This substance with a complex name, after treatment with barium hydroxide, becomes an excellent detergent. It would seem, what is the danger? But formaldehyde is included in the list of substances with carcinogenic properties. Although the degree of its danger has not yet been established, one cannot ignore the fact that formic aldehyde is deadly to animals. According to official data from many scientific centers of the world, the connection between the use of formaldehyde in the production of paints, resins, textiles, plastics and the occurrence of oncological neoplasms in humans has been proven. The risk of developing nasopharyngeal cancer is especially high.
