What Is Iodoform?
Iodoform is a type of iodine-containing compound called trihalomethane.
Chloroform, a well-known anesthetic, is also a type of trihalomethane and is also called “triiodomethane.” It exists as a solid at room temperature, in the form of shiny yellow crystals or powder.
It is almost insoluble in water, but is soluble in organic solvents such as diethyl ether and insoluble in ethanol. It is also slightly volatile at room temperature.
The chemical formula and molecular weight of iodoform are as follows:
- Chemical formula: CHI3
- Molecular weight:393.7
- IUPAC name: triiodomethane
- CAS Number:75-47-8
Uses of Iodoform
Iodoform is used as a disinfectant for wounds and ulcers and as an antiseptic for dental root canals, taking advantage of its high disinfectant effect. Specifically, it is often used in the form of gauze coated with iodoform or blended with eugenol cement to fill deciduous teeth.
The disinfectant effect of iodoform is said to be stronger than ethanol and only weaker than sodium hypochlorite. When using it, care should be taken to avoid getting iodoform powder or dissolved solution in the eyes. In addition, soap can weaken the effect of iodoform, so it is necessary to rinse off the soap before use.
However, iodoform has a specific odor, and disinfectants with stronger effects have been created. As a result, the distribution of iodoform is gradually decreasing and other chemicals are being used. However, iodoform has three iodine atoms and is extremely reactive, and because of its reactivity, it is sometimes used as a reagent in the field of organic chemistry.
Because it contains only one carbon atom, it is often used as an electrophile in methylating agents. Today, opportunities to use it as a reagent are more common than its use as a chemical.
Properties of Iodoform
Iodoform gradually liberates iodine in the blood. Since the liberated iodine has an oxidizing effect, it can exert a strong disinfectant effect on tetanus bacteria and tuberculosis bacteria, which secrete a reducing substance.
However, when iodine levels in the blood become high, there is a risk that iodine will bind to proteins in the body and cause neurological poisoning symptoms such as delirium, sleep disorders, memory impairment, and depression. Therefore, it is important to observe the dosage and administration when using this product.
In addition, it should not be ingested by nursing mothers because of the risk of transfer into breast milk and causing hypothyroidism in newborns. Patients with thyroid problems should be administered with caution because they have difficulty regulating iodine in the blood.
Other Information on Iodoform
How Iodoform Is Made
Iodoform is easily decomposed by light. Therefore, when storing iodoform, it should be stored in a light-shielded brown container away from direct sunlight. Iodoform can also be produced through a reaction called the “iodoform reaction.”
The iodoform reaction is a reaction in which iodoform and carboxylic acid are formed by adding a strong base such as sodium hydroxide and a single iodine to a ketone or aldehyde with an acetyl group. In addition, secondary alcohols are oxidized by iodine and converted to ketones, so alcohols that would otherwise be oxidized to ketones with acetyl groups (methyl ketones) can also produce iodoform in this reaction.
The formation of iodoform in this reaction will result in a yellow precipitate in the flask or test tube. This phenomenon is used to detect ketones and aldehydes with acetyl groups. However, for actual structural analysis, instruments such as NMR and IR, which can determine the structure in more detail, are used.
In high school chemistry textbooks, the iodoform reaction is introduced as a method for structural analysis, but because the information obtained is limited and labor-intensive, the iodoform reaction is not used in structural analysis.