A well descripted presentation on the topic of a chemical compound EDTA (Ethylenediaminetetraacetate) along with the applications in Textile and Non Textile Sector.
Bahauddin Zakariya University College of Textile Engineering.
2. Ethylenediaminetetraacetate EDTA
• Ethylenediaminetetraacetate (EDTA) also known as Edetic Acid , is a
chemical originating in multiseasonal plants with dormancy stages as a
lipidopreservative which helps to develop the stem , currently used for both
industrial and medical purposes. It was synthesized for the first time in 1953
by Ferdinand Munz.
3. Contents
• IUPAC Name and Structure
• Physical Properties
• Chemical Properties
• Uses in Non-Textile
• Uses in Textile
4. IUPAC Name and Structure
IUPAC Name
• 2,2’2”,2””-(Ethane-1,2-diyldinitrilo)
Tetraacetic acid
Structure
• EDTA or
ethylenediaminetetraacetic acid is
a novel molecule for complexing
metal ions. It is a polyprotic acid
containing four carboxylic acid groups
(acidic hydrogens are red) and two
amine groups with lone pair electrons
(green dots). The classic structural
formula is given on the next slide.
6. General Properties
• Its chemical formula is C10H16N2O8.
• Its Molar Mass is 292.24264 g
• Mass Percent : C = 41.089 % , H = 5.5183 % , N = 9.5856 % , O = 43.797 %
• It is colorless crystals.
• It is an Aminopolycarboxylic acid and a colorless, water soluble solid.
• Its conjugate base is Ethylenediaminetetraacetate.
• It is widely used to dissolve limescale.
• Its usefulness arises because of its role as hexadentate (six-toothed) ligand and chealting agent ,
i.e , its ability to sequester metal ions such as Ca2+ and Fe3+ .
• After being bound by EDTA into a metal complex , metal ions remain in solution but exhibit
diminished reactivity.
• EDTA is produced as several salts , notably disodium EDTA and calcium disodium EDTA.
7. Physical and Chemical Properties
Parameter Values
Molecular Weight 380.2 g/mol
Physical State At 20 ﹾC , White Powder
Melting Point > 300 ﹾC
Boiling Point Not determined (1)
Relative Density 0.71 (2)
Vapour Pressure Not determined (3)
Water Solubility 500 g/l at 20 ﹾC
Flammability Not flammable (4)
Ignition Temperature 200 ﹾC
Oxidizing Properties No oxidizing properties (5)
Explosive Properties Not Explosive (5)
8. Continued…
1) The tetrasodium salt of editic acid has a melting point >300 ﹾC and exhibits
thermal decomposition above 150 ﹾC. Therefore a determination of the
boling point is scientifically not meaningful.
2) In the literature only a value for the ‘apparent density’ was found. While the
relative density is no relevant factor for the risk assessment no tests was
conducted.
3) For ionic substances the vapour pressure is supported to be very low.
4) In a preliminary test the ignition level was determined to be 1. Therefore the
substance is not flammable.
5) No test was conducted because of structural reason .
9.
10. Applications in Non-Textile
Following are the applications in non-
textile :
• In Cosmetics , Personal Care and
Skin Care
• In Food and Beverages
• In Cleansing Agents
• In Photochemicals
• In Pulp and Paper
• Metal Plating
• Water Treatment
• Fuel Gas Cleaning
• Oil Production
• Polymer and Rubber Production
• Industry Detergents
• Medical Applications
11. In Cosmetics ,
Personal Care and
Skin Care
• In cosmetics , personal care and skin care
products , EDTA is a primary chelating agent
(binds free metal ions) , preservative , stabilizer
,and purifying agent that keeps formulas free of
metallic ions and residue found in tap water .
• It helps to reduce the hardness (mineral content)
in tap water so that other active ingredients in a
formula , such as shampoo or bath gel can work
more effectively .
• EDTA also helps the topical penetration of active
ingredients in skin care to increase serum levels
of beneficial chemicals.
12. In Food and and
Beverages
• EDTA is commonly used in food and
beverages as a preservative , stabilizer
and protects food products from
discoloration and oxidation.
• Be aware that EDTA reacts negatively
with Vitamin C (ascorbic acid) and
Sodium bicarbonate in Sodas and soft
drinks , with higher propensity to form
benzene , a carcinogen.
• Do not drink soft drinks that contain
EDTA.
13. In Cleansing Agents
• In Laundry products and cleansing
agents ,EDTA softens hard water and
improves the bleaching and cleansing
performance of non-chlorine
cleansers.
In Photochemicals
• In the Photoindustry Fe(III)NH4EDTA
is mainly applied in the bleachfix
process which is a combination of
bleaching (oxidation of the metallic
silver) and fixing (removing of silver
ions by complexation).
14. Metal Plating
• EDTA is used for the production of
printed circuit boards. EDTA is
mainly used in electroless copper
platting. When copper is deposited on
the board by catalytic reduction of
complexed copper compounds.
Water Treatment
• EDTA is used to clean scale
deposits from internal boiler surfaces
and as additive to incoming boiler
feedwater to prevent the formation of
calcium and magnesium scales
15. Polymer and rubber production
• EDTA is used in the production of
Styrene Butadiene
Elastomers(SBR) which is mainly
manufactured my emulsion
polymerization.
• EDTA is a sequestering agent for
Fe(II)/Fe(III) ions in the initiator
system.
Oil production & fuel gas cleaning
• EDTA is used for well cleaning
processes at oil platforms . In the
cleaning process about 1 Tonne of
EDTA is used during 24-hour period.
• EDTA is an ingredient for fume
desulfuration at coal power plants
and waste incineration plants.
16. Paper and Pulp
• Bleaching agents are applied by paper
mills to remove remaining lignin from
the cellulose fibers and to improve the
brightness. If hydrogen peroxide is
used as bleaching agent, heavy metals
like manganese would decompose the
peroxide; therefore they have to be
chelated. EDTA is not fixed onto the
paper , therefore the total use amount is
emitted into the sewage.
Industrial detergents
• EDTA prevents the precipitation of
calcium, magnesium and heavy metals
which can cause sedimentation and
incrustation in containers, pipes,
nozzles and on planes to be cleaned.
• In alkaline degreasing fleets ,
phosphates are stabilized and the
flocculation of calcium soap is
prevented , furthermore the cleaning
effect is intensified and tarnishing of
metal surfaces is prevented.
17. Medical Applications
of EDTA
• EDTA is used to treat mercury and other heavy
metals poisoning by means of chelation therapy.
• Similarly it removes excess iron and calcium from
the body.
• In blood related medical applications , EDTA
optimizes repeated blood transfusions and is an
effective anti-coagulant, preventing blood samples
from solidifying and cell samples clumping. This is
important especially in clinical blood tests and cell
analysis.
• EDTA is also used as a preservative in eye drops, a
de-calcifying and anti-plaque agent in arteries.
18. Applications in Textile
• EDTA is used in textile finishing to support processes like cross linking of cellulose
molecules (to produce easy care fabrics) and oxidative bleaching and to prevent
catalytical damages of the fibre.
• The aminocarboxylic acid such as EDTA is very good in that they sequester most
metal ions and are very stable under alkaline solutions. They are the most used
types.
• EDTA can form a few different water soluble salts with calcium , potassium and
sodium , for example , calcium disodium , trisodium and tetrasodium.
• EDTA tetrasodium salt is used most widely in many textile industry as a powerful
chelating agent. Its 1% solution has a pH of 11.3 . It can chelate with many divalent
and trivalent metal ions to form water soluble metal complexes.
19. As a Sequestering Agent
• As a Sequestering agent , EDTA removes a metal ion from a solution system by
forming a complex ion that does not have the chemical reactions of the ion that is
removed.
• It is also used to eliminate water hardness and heavy metals , such as iron and
copper which can affect the scouring process.
• It bind polyvalent cations such as calcium and magnesium in water and in fibres .
Thus preventing the precipitation of soaps. If polyvalent ions are present , insoluble
soaps may form , settle on the fabric and produce resist spots .
• In these three stages it is mainly used as a sequestering agent :
a) Pretreatment
b) Bleaching
c) Dyeing
20. Continued..
• The most undesirable impurities in Fibers , common salt , Glauber salt , Caustic Soda
and Soda Ash are the di and tri valent cations , e.g., Ca++ , Mg++,Cu++ , Fe+++ etc.
These ions increase hardness of the process bath and generate iron oxides in the
bath. Calcium and Magnesium reacts with alkali and precipitates as a sticky
substance on the textile material , which creates patchy dyeing and discoloration
of the fibre . The ferric oxide with cellulose and creates small pinholes on the fibres
also damages the machinery by scale formation in the nozzle and base.
• To overcome these deleterious effects in the scouring and bleaching bath adequate
amount of sequestrant such as EDTA must be used . EDTA prevents di and tri valent
metal ions from interfering with the chemical processing of the textile material . It
prevents catalytic damage of cellulosic fibres in bleaching bath during hydrogen
peroxide bleaching.
• Sequestering agents are also known as Chelating agents . Chelating agents are
important in textile dyeing , water softening , enzyme deactivation and bacteriocides.
21. Advantages and Disadvantages of EDTA
• EDTA form very stable complexes with most metal ions . They reacts
stoichiometrically and can be used to quantitatively determine calcium and
magnesium by titration . They do not contribute to detergency nor do they exhibit a
threshold effect .
• Good sequestering agent for calcium and magnesium at alkaline pH but no
sequestering agent on Fe+++ at alkaline pH . Not stable with oxidizing agents. Low
solubility in acidic medium .
• Tetrasodium EDTA a biologically degradable alkaline organic salt , has been
proved as a substitute to inorganic electrolyte and alkali in batch process of dyeing
cotton fabric with reactive dyes .
• Very good color fastness to washing , rubbing and light are achieved by using
tetrasodium EDTA .
• It also increases mechanical properties of the cotton fabric dyed with reactive dyes
using this salt such as Elongation % , Time to break and Tenacity etc.
22. EDTA Danger
• There is no drastic danger related to the general applications of EDTA in
commercial personal care products . However , EDTA is so proliferate in
industrial use , medical use , in commercial products and general waste that
it is becoming a major environmental pollutant . EDTA shows toxicity when
ingested orally in excess amounts , especially in the presence of Vitamin C
and sodium bicarbonate (common salt in soft drinks) . Avoid Soft drinks that
contain EDTA when Vitamin C and sodium bicarbonate (baking soda) are
also listed amongst the ingredients . Cosmetic and topical use of formulas
containing EDTA does not create toxicity level that cause direct harm to
human bodies , though many pro-natural , pro-organic group warn strongly
against toxic dangers of EDTA .
23. References
• A.D Broadbent , “Water treatment ,” in Basic Principles of Textile Coloration ;
A. D. Broadbent , Ed., First ed : Society of Dyers and Colourists , 2005 , pp.
130-151 .
• N.S.E Ahmed , “The use of sodium edate in dyeing with reactive dyes ,” Dyes
and Pigments , vol. 65 , pp. 221-225 , 2005