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 C23H25CLN2.

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 [C6H5C{C6H4N(CH3)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).
C6H5CHO + 2{C6H5N(CH3)2} ------------- C6H5CH{C6H4N(CH3)2}2 + H2O
• 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:
C6H5CH{C6H4N(CH3)2}2 + HCL + ½ O2 ---- [C6H5C{C6H4N(CH3)2}2]CL + H2O
• The hydrolysis reaction of malachite green results in formation of alcohol.
[C6H5C{C6H4N(CH3)2}2]CL + H2O ---- C6H5C(OH) + {C6H4N(CH3)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: C14H8O4
• Melting point: 289.5 0c
• Boiling point: 430 0C
• 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 ALCL₃ 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.

14. THANK YOU