Showing posts from March, 2022

Malachite Green: Definition, Synthesis, Properties and Applications

What is Malachite Green? Malachite green is a type of Triphenyl methane dye that is used as a dyestuff for materials like silk, leather, and paper. It is bright green and can be used as an antimicrobial agent in aquaculture. Synthesis of Malachite Green Malachite green can be prepared by reaction of Benzaldehyde with N, N-dimethyl aniline in the presence of H₂SO₄ to form a triphenylmethane derivative. The subsequent oxidation with PbO₂ followed by treatment with an excess of concentrated HCl yields a green dye known as malachite green. Properties of Malachite Green Malachite green is green, crystalline, and water-soluble. Leuco form of malachite green is electrically neutral and undergoes a photoionization reaction that yields the cationic form of malachite green. It is toxic, thus not advisable to consume. Applications of Malachite Green It is used as a dye to color materials like silk, leather, and paper. It is used as an antiseptic for bacterial infection. It is used to catch thi

Conducting Polymers: Definition, Examples, Properties and Applications

What are Conducting Polymers? As the name suggests organic polymers that conduct electricity are known as conducting polymers. They are also known as intrinsically conducting polymers (ICPs) and they have alternating single and double bonds along the polymer backbone (conjugated bonds) or that are composed of aromatic rings such as Phenylene, naphthalene, anthracene, pyrrole, and thiophene which are connected through carbon-carbon single bonds. Examples: Polyacetylene, Polypyrrole, Polyaniline, etc What is the reason behind conducting nature of these polymers? Conducting polymers comes in two forms that are doped conducting polymers and non-doped conducting polymers. The conductivity of non-doped conjugated polymers is due to the existence of a conductivity band similar to a metal. In a conjugated polymer, three of the four valence electrons form strong sigma bonds through sp² hybridization where electrons are strongly localized. The remaining unpaired electron of each carbon atom re

Alizarin Dye: Definition, Synthesis, Properties and Application

What is Alizarin Dye? Alizarin is a red dye having chemical formula C₁₄H₈O₄ which is generally used to dye cotton, wool, and silk.  Alizarin was originally obtained from the root of a common madder plant called Rubia tinctorum. It is also known as Turkey Red as it was best dyed in Turkey and in 1869, it becomes the first natural dye to be duplicated synthetically. Synthesis of Alizarin Following are some methods for the synthesis of alizarin: 1. From anthraquinone The starting material for the synthesis of alizarin is an anthraquinone. It can be easily obtained by Friedel-crafts acylation of benzene with phthalic anhydride. Anthraquinone is then sulfonated with concentrated sulphuric acid at a high temperature to give anthraquinone-b-sulphonic acid. Alizarin is obtained by fusion of anthraquinone-b-sulphonic acid with caustic soda. 2. By bromination of anthraquinone Another synthesis is given by Graeve (in 1869). In this method, anthraquinone is brominated to yield dibromo anthraqui