Iodine

Description

Iodine was discovered in 1811 by Bernard Courtois, and is classed among the rarer elements. Iodine is a required element by many species, including humans. It has been recognized as preventative against goiter since 1819, and is used in iodized salt for this purpose. Iodine is also used as a dough oxidizer in commercial bread making.

Chemical properties

Iodine is available as bluish-black crystals with a metallic luster and a pungent odor. It is slightly soluble in water (0.03 g/100 g). It is stable under ordinary conditions of use and storage. It reacts violently or explosively with acetaldehyde and acetylene, and reacts with ammonium hydroxide to form shock-sensitive iodides on drying.
Iodine occurs in many different forms that can be blue, brown, yellow, red, white, or colorless. Most forms of iodine easily dissolve in water or alcohol.

The Uses of Iodine

To  the SM (1.77 Kg, 8.58 mol) in anhydrous DMF (8 L) under N2 at 10 C  was added NIS (1.93 Kg, 8.58 mol) in  portions over 10 min. The reaction mixture was stirred at RT for 2 h, after which  time it was cooled using an ice bath and quenched with sat aq Na2CO3 (5 L) and extracted with EtOAc (2 x 15 L). The combined organics were washed  with sat aq Na2CO3 (2 x 5 L), H2O (3 x 2 L),  dried (Na2SO4), and concentrated in vacuo. The resulting  crude material was purified by silica gel column chromatography (25-40% EtOAc/hexanes)  to provide the product. [1.47 Kg, 57% over 2 steps]

Background

Iodine is commonly used as an antiseptic for minor cuts and abrasions, preventing infections that may result from contaminated wounds. Additionally, iodine has been studied in the treatment of fibrocystic disease and breast cancer.

Indications

Investigated for use/treatment in breast disorders (unspecified) and pain (acute or chronic).

Production Methods

The principal method used to recover iodine from oil brines involves the oxidation of iodide by chlorine, followed by removal of the volatile iodine from solution with an airstream. The iodine is reabsorbed in solution and reduced to hidrotic acid with sulfur dioxide. The solution is then chlorinated to precipitate free iodine, which is further purified by treatment with concentrated sulfuric acid.

Biological Functions

Inhibition of the release of thyroid hormone by iodide is the basis for its use in hyperthyroidism. Iodide decreases the vascularity of the enlarged thyroid gland and also lowers the elevated BMR. It also has been suggested that excess iodide might change the conformation of thyroglobulin, making the protein less susceptible to thyroidal proteolysis.

Hazard

Iodine vapors are an irritant to eyes, nose and mucous membranes.Inhalation can cause headache, irritation, and congestion of lungs. Oralintake can produce burning of the mouth, vomiting, diarrhea, and abdominalcramps. Skin contact can cause rashes.

Toxicity evaluation

Iodine is a powerful oxidizing agent and has a direct action on cells by precipitating proteins. The affected cells may be destroyed. In addition to the primary irritant action of iodine, this compound can act as a potent sensitizer.