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Quick Detail:
Ethylenediaminetetraacetic acid (EDTA) is a chelating agent
produced as a series of salts. A chelating agent is a material that
tightly binds or captures metal ions.
Salts of EDTA are typically sold as an aqueous solution for
controlling / binding metal ions over a broad pH range in aqueous
(water-based) systems.2 Salts of EDTA typically exist as a light
amber liquid and some have a slight amine odor. Some salts are sold
as dry powders.
Occupational exposure is dependent upon the conditions under which
salts of EDTA are used. Under fire conditions, salts of EDTA can
decompose and the smoke may contain toxic and/or irritating
compounds.
Based on currently available information, there is no indication of
harmful effects of EDTA due to long-term exposure to low
concentrations found in the environment.
Description:
EDTA is an aminopolycarboxylic salt. The various salts of EDTA
typically exist as clear to amber liquids. Some have a slight amine
odor. They can be used as chelating agents over a broad pH range in
aqueous systems. Some salts are produced as dry powders and
crystals. These salts are water soluble, but insoluble in acid and
organic liquids
Chelating agents bind or capture trace amounts of iron, copper,
manganese, calcium and other metals that occur naturally in many
materials. Such naturally occurring metals can cause foods to
degrade, chemical degradation, discoloration, scaling, instability,
rancidity, ineffective cleaning performance and other problems
Applications:
1) Agriculture – to stabilize formulations and to provide
micronutrients to fertilizers
2) Cleaning products – to remove hard water scale, soap film, and
inorganic scales in a wide variety of cleaning products and
formulations, including hard surface cleaners, institutional
cleaners, laundry detergents, liquid soaps, germicidal and
anti-bacterial cleansing preparations, and vehicle cleaners
3) Metalworking – for surface preparation, metal cleaning, metal
plating, and in metalworking fluids
4) Oil field applications – in the drilling, production, and
recovery of oil
5) Personal care products – to increase effectiveness and improve
stability of bar and solid soaps; bath preparations; creams, oils,
and ointments; hair preparations, shampoos and almost every type of
personal care formulation
6) Polymerization – for suspension, emulsion, and solution
polymers, both in polymerization reactions and for finished polymer
stabilization
7) Photography – as a bleach in photographic film processing
8) Pulp and paper – to maximize bleaching efficiency during
pulping, prevent brightness reversion, and protect bleach
potency
9) Scale removal and prevention – to clean calcium and other types
of scale from boilers, evaporators, heat exchangers, filter cloths,
and glass-lined kettles
*0) Textiles – in all phases of textile processing, particularly
the scouring, dyeing and color stripping stages
*1) Water treatment – to control water hardness and scale-forming
calcium and magnesium ions; to prevent scale formation
*2) Consumer products – in food and pharmaceutical applications
Specifications:
CAS Number: *********1
Chemical Formula: C*0H*2N2O8CuNa2
Molecular Weight: **7.7
Appearance: blue crystalline powder
Copper chelated: *4.5%min
Water insoluble: 0.1%max
PH (1% aqueous solution): **7
Loss on drying: 1 %max
Heavy metals (as Pb): 4 ppm max
As: 1ppm max
Competitive Advantage:
Metal chelation is important because it makes metal ions more
available for uptake by plants. Positively charged metal ions, such
as Zn, Mn, Cu and Fe, readily react with negatively charged
hydroxide ions (OH-), making them unavailable to plants. OH- ions
are abundant in alkaline or neutral soils and soil-less medias.
The ligand coats the metal ion, protecting it from the surrounding
OH- ions. The complex can then be easily absorbed by the plant,
where it is being degraded and consumed as micronutrients.
The strength of the chemical bond between the ligand and the metal
ion depends on the type of ligand, the type of ion and the pH. The
stronger the bond, the more stable the metallic ion and each
chelate has a characteristic "stability diagram".
Here are examples for stability diagrams for a Copper chelate and a
Zinc chelate. It is obvious that in specific pH levels, the
complexes are not stable, i.e. the ligand tends to separate from
the metal ion.
