Formaldehyde, which is scientifically known as methanol, is a nasty gas and is the smallest aldehyde. Its chemical formula is CH2O. Formalin boiling point is -19 ° C and its density is 815 kg / m³. Its appearance is as an aqueous solution.
Synonyms with formalin: methanol, formaldehyde, methylene oxide, methyl aldehyde.
Formalin was first discovered by Russian scientist Alexander Butler in 1859. This gas is easily caused by incomplete combustion of carbon-containing compounds. In the forest smoke, a large amount of formaldehyde enters the atmosphere. Apart from this, car exhaust and factory smoke also contain a lot of formalin. Formalin is naturally produced in the atmosphere by the reaction of oxygen with methane and other hydrocarbons under sunlight. Some of the hydrocarbons from the metabolism process also produce a small amount of formalin.
Formalin Production Method:
The starting material in the production of formalin is methanol. Methanol evaporates rapidly and, after mixing with oxygen, produces an explosive gas that is used to prevent the transportation and storage of methanol, fire extinguishers, and refrigerated containers. In the formalin production unit, the methanol is first converted to heat by superheating steam, then mixed with air in a proportion of oxygen and passed over a catalyst bed at 300 ° C. After passing the mixture of gases through the catalyst, the formalin gas reactor unit is produced. The formaldehyde gas, along with nitrogen, carbon dioxide, and water vapor, is removed from the reactor and then cooled into the absorption tower. As a result of the contact, the formalin water in the gas is absorbed and a formalin solution is formed which is stored in the lower part of the tower and then cooled into storage tanks. In general, it can be said that formalin is produced in the industry from the catalytic oxidation of methanol. Metallic silver or a mixture of iron oxide and molybdenum is commonly used as catalysts. When using iron oxide and molybdenum as catalysts, methanol reacts with oxygen at 400 ° C and is produced by a formalin reaction.
Properties of formaldehyde:
Although formaldehyde is a gas at room temperature, but dissolves in water well. Formaldehyde is usually supplied as 37% aqueous solution, called Formalin. Formaldehyde in the water, Polymerized, including small monomers HCHO is interconnected. Usually formalin has a little percentage Methanol to limit Polymerization. Formaldehyde has the same properties as other aldehydes. The difference being, usually, the reaction is more acceptable than other aldehydes.
Formaldehyde is a strong electrophile. So on Aromatic electrophilic substitution, it participates with aromatic compound reactions. It also can undergo an electrophilic uptake reaction with the alkenes. In the presence of base catalysts, it plays a Self-Oxidation - Reduction reaction (Canisario reaction), and produces methanol and Formic Acid Salt.
Formaldehyde gets polymerized irreversibly and produces 5, 2, 1 and 1-trioxane ring polymers or polyoxymethylene linear polymer. Forming these Polymers causes formaldehyde gas to deviate substantially from the ideal gas law. Formaldehyde readily oxidizes with the available Oxygen in the atmosphere, especially at high pressure or at low temperature, and forms formic acid. To prevent this reaction, formaldehyde solution should be kept in bottles with sealed caps.
Formalin has many uses:
As a disinfectant to kill bacteria.
For the storage of biological samples
In Polymer Production Industries
Production of other chemicals
Formalin reacts with phenol, to produce urea and formaldehyde resins melamine.
As viscous resins for plywood production
In the manufacture of molded sponges
Production of insulating sponges
Production of formaldehyde resins
In the paint industry
Production of explosives
In key and socket industries
In the power industry
Manufacture of coated chipboard and MDF sheets
As a disinfectant in poultry and hospitals
The main raw material in the production of hexamine
1: It causes irritation in eyes, nose and redness, tears, eye irritation, sneezing and coughing and sore throat. Higher levels of it can cause lung irritation, chest pain and shortness of breath. Formalin exposure causes irritation of the oral mucosa, upper respiratory tract, and respiratory malformations. Even though its molecular mechanism is not well understood.
2: According to the information from the International Cancer Institute, formaldehyde is one of the carcinogens that are common in society. Exposure to formaldehyde can also lead to
nasal and sinus cancers, and can lead to leukemia and lymphoma, and increases the risk of throat and nose cancer.
3: Inhalation during infancy causes neurological diseases in adulthood.
4: Formalin can cause asthma in people who have been exposed to it for a long time. But its molecular mechanism is not well understood.
5: Lymph node hyperplasia of the respiratory tract lymphatic tissue is the only detectable effect of formaldehyde vapors on the lymphatic tissues of the respiratory region.
6: As mast cells are widely distributed throughout the airways, formalin appears to make these cells hypersensitive.
7: Contact with formalin solutions can cause skin damage, dryness, scaling, cracking and dermatitis.
8: The deleterious effects of formaldehyde on reproduction and reproductive system have been demonstrated in both human and laboratory animal models.
Safety tips when using formalin:
The following should be observed when working with formalin:
Working with formalin should be done in a well-ventilated area.
Siphon formalin is prohibited by mouth.
Smoking, eating and drinking are prohibited in the place where formalin is kept.
When working with formalin, thick plastic gloves, lab coats and shoes should be worn and face protection or glasses worn.
In case of eye or skin contact with formalin, the eye or area should be rinsed with plenty of water for 15 minutes.
Formalin should be kept away from hydrochloric acid (ink) because its vapor combination with hydrochloric acid creates a very strong carcinogenic substance called dichloromethyl ether.
Formalin should be kept away from heat.
Formalin should be disposed of in non-leak able glass containers and disposed separately from hospital waste.