malachite green and alizarin.pptx

Malachite green is an organic compound that is used as a dyestuff and controversially as an antimicrobial in aquaculture. Malachite green is traditionally used as a dye for materials such as silk, leather, and paper. Despite its name the dye is not prepared from the mineral malachite; the name just comes from the similarity of color.
Alizarin (also known as 1,2-dihydroxyanthraquinone, Mordant Red 11, C.I. 58000, and Turkey Red is an organic compound with formula C14H8O4 that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural dye to be produced synthetically.

1. MALACHITE GREEN AND ALIZARIN DYE TEAM - C SANDEEP (20BSR03051) SVETA YADAV (19BSR03016) NEHA KUMARI (20BSR03020) SHASHANK (20BSR03024)

2. DYES Dyes are the substances used to impart colour to textiles, paper, leather and other minerals such that the colouring is not readily altered by washing, heat, light, or other factors to which the material is likely to be exposed. Examples: acidic dyes (eosin, acid fuchsine, congo red), basic dyes (safranin, crystal violet, methylene blue), malachite green, alizarin etc.

3. Malachite green Malachite green is an organic compound known for its extensive use as a dye. The use of malachite green has also been known for its controversial use as an antimicrobial in the aquaculture industry. The traditional use of malachite green has included its uses as a dye material for silk, leather and paper. Although the name of the compound is malachite green, it is not prepared from the malachite mineral and the name has been associated with it because of its intense green colour. The chemical formula of the compound malachite green is C 23 H 25 ClN 2 .

4. STUCTURES PROPERTIES It has a role as a flurochrome, a histological dye, an antifungal drug, and an antibacterial agent. Malachite green refers to the chloride salt [C 6 H 5 C{C 6 H 4 N(CH 3 ) 2 } 2 ]Cl . The oxalate salt, in addition to the chloride salt, is also available in the market. Its leuco form is electrically neutral and undergoes photoionization that yields the cationic form of malachite green.

5. SYNTHESIS Herman fischer was the first one to prepare leuco malachite green in 1877. He did so by condensing the benzaldehyde and dimethylaniline in the molecular ratio of 1:2. The reaction was carried out in the presence of sulphuric acid. Malachite green is routinely prepared by the condensation of benzaldehyde and dimethylaniline, in turn giving leuco malachite green (LMG). C 6 H 5 CHO + 2{C 6 H 5 N(CH 3 ) 2 } -------------  C 6 H 5 CH{C 6 H 4 N(CH 3 ) 2 } 2 + H 2 O The leuco compound which is colourless relative to triphenylmethane is further oxidized to a cation which is the malachite green. The reaction is as given below: C 6 H 5 CH{C 6 H 4 N(CH 3 ) 2 } 2 + HCl + ½ O 2 ----  [C 6 H 5 C{C 6 H 4 N(CH 3 ) 2 } 2 ]Cl + H 2 O The hydrolysis reaction of malachite green results in formation of alcohol. [C 6 H 5 C{C 6 H 4 N(CH 3 ) 2 } 2 ]Cl + H 2 O ----  C 6 H 5 C(OH) + {C 6 H 4 N(CH 3 ) 2 } 2 + HCl

6. USES As a dye – malachite green has been used as a dye for centuries. For this purpose, kilotons of MG and related triarylmethane dyes are produced each year. Treatment of saprolegnia – malachite green has been used to treat saprolegnia and as an antibacterial. It is active against the oomycete saprolegnia, which infects fish eggs in commercial aquaculture. In freshwater aquariums, it is a popular treatment for ichthyophthirius multifiliis. For theft detection – thieves and pilferers have frequently been apprehended using malachite green. The anhydrous powder is put on the bait, which is usually money. Anyone handling contaminated money will notice that washing their hands will leave a green stain on their skin that will last for several days.

7. As a biological stain – malachite green is also used as a biological stain for examining cell biology and tissue samples under a microscope. Basic fuchsin stains bacteria magenta or red, and MG is used as a blue-green counterstain in the gimenez staining method. Because MG can directly stain endospores within bacterial cells, it is also used in endospore staining; however, a safranin counterstain is frequently used. Alexander’s pollen stain includes MG. MG is used as a saturable absorber in dye lasers or as a pH indicator with a pH range of 0.2 to 1.8. However, this is a relatively uncommon application. In forensic science, leuco-malachite green (LMG) is used as a latent blood detection method. The reaction between LMG and hydrogen peroxide is catalyzed by hemoglobin, which turns the colourless LMG into MG. As a result, the presence of blood is indicated by the appearance of green colour.

8. ALIZARIN Alizarin is a red dye originally obtained from the root of the common madder plant, now made synthetically and used especially to dye, principally for dyeing textile fibers. Historically it was derived from the roots of the madder genus. In 1869, it become the first natural dye to be produced synthetically.

9. STRUCTURES PROPERTIES Molar mass: 240.21 g/ mol Formula: C 14 H 8 O 4 Melting point: 289.5 c Boiling point: 430 C Density: 1.540 g/ cm3 Slightly to sparingly soluble in water

10. SYNTHESIS 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- β -sulphonic acid. Alizarin is obtained by fusion of anthraquinone- β -sulphonic acid with caustic soda.

11. By bromination of anthraquinone: Another synthesis is given by Graeve (in 1869). In this method, anthraquinone is brominated to yield dibromo anthraquinone. The obtained compound, when fused with caustic potash, gives alizarin.

12. Synthesis from catechol: This is a new method for the synthesis of alizarin in which alizarin is obtained when catechol is condensed with the phthalic anhydride in the presence of anhydrous AlCl ₃ or concentrated H₂SO₄ at 70℃ temperature.

13. USES It can be used as a mordant dye in which the resulting color varies with the nature of metal used for mordanting. Thus, we get a red color with aluminium , violet color with iron, and brown violet with chromium. It is used as a purgative. It is used for making printing inks. It is used to dye cotton and wool. In geology, alizarin is used as a stain to differentiate the calcium carbonate minerals, especially calcite and aragonite.

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