When 37% formaldehyde (HCHO) is stored in an aqueous solution is called formalin. It is a naturally occurring organic substance. However, the pure form of formalin is a colorless gas with a pungent smell. The name formalin comes from its similar properties to formic acid.
In 1855, it is first described by a Russian scientist named Alexander Michailowitsch Butlerow. Later in 1867, formalin (HCHO) is produced by the oxidation of methane or methanol by a German scientist, August Wilhelm von Hofmann. Formalin is an important chemical feedstock and has many uses. For example, coating of building materials, food preservatives, disinfectants, etc.
Whereas, according to the World Health Organization (WHO), formalin is a carcinogenic and teratogenic substance. Formalin can also cause health problems in humans, such as irritation of the eye and skin, respiratory diseases, and nasopharyngeal cancer. Inhaling large amounts of formaldehyde can cause central nervous system damage and headaches.
The sterilization effect of formaldehyde on living tissue was first discovered by German physician and pathologist Rudolf Virchow in 1837. Using formaldehyde in large amounts as an antiseptic has long been banned due to its toxicity and carcinogenic effects on humans.
Most common uses of formalin (formaldehyde)
These are the most common uses of formalin or formaldehyde:
- Food preservation
- Dentist floss
- Disinfectant and biocide
- Tissue fixation agent
- Denaturing agent
- Wood preservation
- Antifungal solution
- Adhesive and coatings
- Building materials
- Sanitary products
- Drug testing
Formalin has the ability to preserve food for a long time but it is dangerous to use in food. That’s why it is used indirectly for food preservation or as a disinfectant for food containers. It also occurs naturally in food products. Additionally, it is released as a byproduct of metabolism.
Formalin is a chemical solution that contains formaldehyde and it is primarily used as an antiseptic and preservative for medical equipment and supplies. It is used during dentist floss which is a process of removing food and dental plaque between the teeth. It is also used instead of local anesthesia during oral operations.
Formalin is used as an insecticide and in low concentrations to preserve biological specimens for medical research purposes, including anatomical models and pharmaceutical samples where it kills bacteria.
Formalin is used as a disinfectant in public places such as schools, hospitals, offices, and restaurants. The objects they clean are sanitized from pathogens that cause diseases like tuberculosis and staph infections. Hospitals commonly use formaldehyde for surgical equipment and to remove blood stains. However, formalin can be harmful if inhaled or absorbed through open wounds. It is better to wear gloves when handling it.
Tissue fixation agent
It is used for tissue or cell fixation to preserve for a long time by cross-linking primary amino acids. This cross-linking is exploited by CHIP-sequencing genomic experiments, where these binding proteins are linked on binding sites present on chromosomes. Due to its carcinogenic properties, formalin is banned in many countries as a biocide under the Biocidal Products Directive.
Formalin has many uses and one of them is denaturing. In the process of gel electrophoresis, it is used for denaturing the RNA. It is because RNA makes a secondary structure during the process. In this way, formalin prevents RNA from making further structures.
Formalin solution is an effective remedy for preventing fungal growth on a number of surfaces, especially cutting boards. Formalin solution acts as a sterilizing agent that helps remove potentially harmful pathogens from food preparation surfaces, leaving your kitchen safer and more sanitary.
Pharmaceutical companies use formalin for the production of several vaccines, anti-infective drugs, and hard gel capsules. Formalin inactivates the viruses which cause diseases. It is also used to stop the growth of bacteria in medicines.
Formalin is essential for the production of cosmetic products. These products have component substances that can release formaldehyde which acts as a disinfectant and also prevents the growth of bacteria and fungi.
Adhesive and coatings
It is used for the production of adhesive and coating materials. Glues and rubber are mainly produced by formalin. Formaldehyde is very reactive and is used as a reaction initiator in the synthesis of rubber. Paints mainly use formalin for better coatings.
Building and construction materials
Formalin-based resins are used in the production of engineered wood products such as, cabinetry, molding, furniture, shelving, stair, wall sheathing, and household furnishings. These resins have a wide range of uses in the panel and board products.
Formaldehyde is used as an industrial disinfectant when producing sanitary products. For example, napkins, paper towels, tissues, etc.
Formalin is used as a solvent in drug testing. For example, a solution of formaldehyde and 18 molars of concentrated sulfuric acid, commonly known as Marquis reagent can detect bases and other chemical compounds.
It is used to wash photographic chromogenic color print at the final step. Formalin solution is used for this purpose in low concentrations.
Applications of formalin (formaldehyde)
Industries use formalin as a precursor material for the manufacturing of major and complex compounds which are formed on a large scale.
These are the following materials:
- Urea-formaldehyde resin
- Melamine resin
- Phenol formaldehyde resin
- Polyoxymethylene plastics
- Methylene diphenyl diisocyanate (MD
These polymers are adhesive in nature and are used in plywood, carpeting, insulation, and automobile components. Formaldehyde is also used for the production of polyfunctional alcohols like pentaerythritol which is used for the production of explosives materials and paints.
Due to the antiseptic properties of formalin, it is used in medical applications and equipment. In operation theaters, formalin is used to kill bacteria and viruses. In warts, it is used to clean floors and blood stains on bed sheets. Many vaccines are produced by using formaldehyde.
Formalin has an important role in making automobiles lightweight and power efficient. Formalin resin is used to make the interior components of automobiles that are resistant to high temperatures. For example, the components under the bonnet of the automobile.
The exterior primer uses formaldehyde in its manufacturing which is used for finishing the outer body of an automobile. For example, coat paint, tire cord adhesives, brake pads, etc. are produced by the material used formaldehyde.
Can formaldehyde cause cancer?
Formaldehyde (HCHO) is a carcinogenic and banned by World Health Organization. These are diseases caused by formaldehyde:
- Irritation of the eye and skin
- Respiratory diseases
- Nasopharyngeal cancer
Why formalin is used in food?
We cannot store food for a long time. To preserve food, formalin can be used. Due to its carcinogenic properties, it is banned to use for preserving food.
Why formalin is used for preservation?
Formalin is a strong disinfectant and antiseptic agent and has the ability to preserve food for a long time.
What is the advantage of formalin?
There are the following advantages of formalin:
- It is can use as a disinfectant.
- Formalin is used for building materials.
- Formaldehyde is used for medical applications.
- It is also used in industrial applications.
What is formaldehyde used for in hospitals?
It is used as a disinfectant and antifungal agent in the wards and operation theaters.
Is it good to add formalin to milk?
No, it can be dangerous to add to food products because it is carcinogenic.
What are the side effects of formalin added as preservatives for keeping the fish fresh?
There are the following side effects of formalin:
- Irritation of skin
- Cancer of internal organs
- Respiratory diseases
- Formaldehyde: Chemistry, Applications, and Role in Polymerization by Chan Bao Cheng and Feng Hu Lin