Tetraacetylethylenediamine
Tetraacetylethylenediamine is incorporated into fabric washing powders as a bleach activator.
In the wash, Tetraacetylethylenediamine undergoes almost quantitative perhydrolysis to diacetylethylenediamine (DAED) and peracetate, providing efficient bleaching and hygiene benefits at low wash temperatures.
DAED, TAED, and Triacetylethylenediamine (TriAED) are readily and completely biodegradable and are substantially removed during sewage treatment.
TAED WHITE
Use of the substance/preparation.
Industry sector: Detergents Intermediates
Type of use: Perborate activator
Composition/information on ingredients
Chemical characterization
Tetra acetyl ethylene diamine with sodium carboxymethyl cellulose
CAS number: 10543-57-4
Chemical name: N,N,N,N-tetraacetylethylenediamine
Empirical formula C 10 H 16 N2 O4
Molecular mass: 228 g/mol
CAS no. 10543 – 57 – 4
EINECS no. 234 – 123 – 8
UIPC nomenclature N,N-1,2-ethanediylbis (N-acetyl-)acetamide
Other names N,N-ethylenebis-diacetamide
N,N,N,N-tetraacetyl-1,2-diaminoethane
USES OF TAED
Heavy duty detergents
Concentrates
Compact powders
Bleach boosters
Soaking agents
Dishwashing detergents
HDL anhydrous
Denture cleaners
Disinfectant cleaners
Hard surface cleaners
Textile bleaching
Paper bleaching
Tetraacetylethylenediamine, also called TAED, is used in detergent formulations as a biodegradable activator for oxygen-based bleaching agents.
They ensure excellent stability in storage, prevent interaction with sensitive detergent components and guarantee optimum utilization during the washing process.
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Tetraacetylethylenediamine is compatible with all commercial builder systems and also display an excellent degree of conservation after several weeks storage.
However, the builder system has a significant influence on the stability of the persalt.
In particular (uncoated) sodium percarbonate rapidly loses activity in formulations containing zeolite.
Very good storage stability is guaranteed on the other hand in formulations free of zeolite based on SKS-6.
Tetraacetylethylenediamine in formulations containing SKS / percarbonate
The change from formulations containing zeolite / perborate to more environmentally friendly detergents based on SKS-6 and percarbonate necessarily involves an increase in the pH value of the washing liquor.
As a result there is a shift in the performance spectrum of the Tetraacetylethylenediamine.
Whereas slight losses in performance have to be accepted with regard to hydrophilic soiling, the bleaching performance is improved with regard to more hydrophobic types of stains.
Tetraacetylethylenediamine in bleach boosters
Bleach boosters are increasingly gaining importance as detergency boosters and a component of building block systems.
They are used either to pretreat the wash (soaking) or as an additive to the normal detergent, if the heavy soiling of the wash so demands.
Combined with light duty or liquid detergents – used specifically and only if necessary– they can totally replace detergents containing bleach and make a significant contribution towards safeguarding the environment.
The main components of all bleach boosters are persalts – generally percarbonate (20–80%) – and Tetraacetylethylenediamine (3–15%).
In addition enzymes, surfactants and sequestering agents may be incorporated to enhance the efficiency towards stubborn stains such as grass, fruit or blood stains.
The appropriate choice of filler is crucial for the optimum performance of the bleach boosters.
This should take over the function of a pH regulator, buffer or stabilizer or as inert material improve the formulation’s thermostability.
The full bleaching power of bleach boosters containing Tetraacetylethylenediamine is realized in particular with the 40 and 60°C wash as well as in the soaking process at 20–40°C.
Crucial for the efficiency is the pH value of the washing liquor, which is a result of both the basic detergent and the bleach booster.
Formulations containing Tetraacetylethylenediamine based on 25% persalt are in most cases clearly superior in performance compared to bleach boosters consisting of pure persalt.
A significant additional effect is to be seen in the germicidal action.
Under certain circumstances the bleach boosters can affect the performance of the enzymes of the basic detergent negatively on account of the high content of bleaching agent. Optimum enzyme and bleaching performance is observed by the delayed addition of the bleach boosters (10–15 min. after the start of the wash).
Bleach boosters containing Tetraacetylethylenediamine are characterized by good storage stability.
However,it must be noted when choosing the formulation that mixtures of fire accelerating percarbonate with organic materials such as Tetraacetylethylenediamine or surfactants may have a tendency towards exothermic decomposition under unfavourable processing or storage conditions.
The processing instructions for persalts and Tetraacetylethylenediamine are to be observed to ensure safe handling.
In addition thermochemical investigation of the final formulation is advisable.
Special types of Tetraacetylethylenediamine granules for use in bleach boosters can be obtained commercially.
Optimized bleaching as a result of optimized additives
The efficiency of the Tetraacetylethylenediamine system can be optimized by the appropriate choice of additives.
Whereas the addition of sodium carbonate tends to have a negative effect on the bleaching action, acid substances – in the correct dosage – can increase the bleaching performance.
The use of citrate is advantageous, because it assists the bleaching reaction positively.
Activated and non-activated bleach booster formulations
In the case of bleach boosters without Tetraacetylethylenediamine (non-activated) the addition of an alkaline filler is recommended to assist the bleaching performance of the hydrogen peroxide.
In systems containing Tetraacetylethylenediamine the pH value should ideally be between 9 and 10, whereby the activity of the peracetic acid formed can be additionally improved.
Additives, like ox-gall soap or sequestering agents, have the effect of increasing the efficiency with regard to certain types of dirt.
Better bleaching results due to the activated bleach
The performance of different bleach boosters was tested at 40°C combined with different basic detergents, which cover a wide spectrum of the heavy duty, light duty and liquid detergents available on the market.
Advantages are clearly revealed for formulations containing Tetraacetylethylenediamine, the performance of which is up to 20% above that of pure percarbonate.
Bleach boosters in the soaking process
Bleach boosters containing Tetraacetylethylenediamine are clearly superior to non-activated formulations in the soaking process at room temperature.
Reaction periods of more than 12 hours result in only marginally additional bleach effect.
Influences on the bleaching result
Optimization of a bleach booster is generally more difficult than that of a heavy duty detergent.
The final bleaching result is not only influenced by the bleach booster, but also by the basic detergent used.
The fine adjustment is only possible through the manufacturer, since the latter is able to control the consumer’s behaviour with the instructions for use on the package.
Tetraacetylethylenediamine in denture cleaners
The ingredients of modern denture cleaners are largely substances with cleansing, oxidizing and disinfectant properties.
In most cases a complex bleaching system is used consisting of caroate, perborate or percarbonate as well as Tetraacetylethylenediamine.
Tetraacetylethylenediamine provides for the necessary hygiene and the fast and complete removal of bleachable soil on the teeth.
The cleaning performance is assisted by a mixture of acid components (citric acid or amidosulphonic acid) with sodium carbonate or hydrogen carbonate, which produce an effervescent effect and support the mechanical release of food remains.
At temperatures of 30–40°C and reaction times between 10 and 20 minutes the use of a disintegration aid is recommended for faster solubility.
The use of granulated Tetraacetylethylenediamine is recommended for use in denture cleaners to guarantee optimum stability in storage.
The typical pH value of the cleaning tablets is in the range of 6–8.
Tetraacetylethylenediamine does not display the optimum bleaching action, but particularly in this range the peracetic acid formed proves to be highly reactive towards microorganisms and therefore makes Tetraacetylethylenediamine an indispensable constituent of modern denture cleaning tablets.
Sodium perborate x 1 H2O 25–35%
Potassium peroxomonosulphate 10–25%
Tetraacetylethylenediamine 2–5%
Sodium hydrogen carbonate 10–20%
Sodium carbonate 5–10%
Trisodium citrate 5–10%
Surfactant 0.5–1%
Others (polyethylene glycol,
fillers, preservatives, flavouring
and colouring matter etc.) ad 100%
Tetraacetylethylenediamine in dishwashing detergents
The ingredients of modern cleaners are builders (silicates, citrates or phosphates), alkali sources (soda, bicarbonate, silicates), dispersing agents, low foaming surfactants, enzymes and the bleaching agent.
The pH value is lowered to 9–11.
It is therefore an ideal field of application for the environmentally friendly Tetraacetylethylenediamine system with the usual washing temperatures today of 45–65°C.
At the same time it enables highly active proteases and amylases to be used, which assist in removing food containing protein and starch from the dishes being washed.
Tetraacetylethylenediamine is compatible with the ingredients of modern dishwashing detergents.
It can be used in formulations both with and without phosphates.
It is stable in powder and also in tablet form.
2–6% Tetraacetylethylenediamine are preferably used combined with 5–15 % perborate monohydrate or percarbonate to achieve the optimum bleaching result even on stubborn stains such as tea for example.
At the same time Tetraacetylethylenediamine suppresses the discolouration of plastic parts, caused by natural dyes in ketchup and food containing curry or paprika.
The peracetic acid formed destroys the microorganisms adhering to the remains of the food and ensures that the dishes being washed up are hygienically clean.
The use of Tetraacetylethylenediamine does not have a negative effect on the formation of a coating or glass corrosion.
Under certain circumstances however the presence of active oxygen may result in the discolouration of silver cutlery.
This involves the formation of layers of silver oxide (possibly also sulphides or chlorides), which are difficult to remove.
In this case the optimum formulation of the Tetraacetylethylenediamine system (concentration, ratio Tetraacetylethylenediamine : persalt) as well as the use of silver protective agents (e.g. triazoles or redox systems on an organic or inorganic base) are recommended.
Optimized dishwashing formulations
The Tetraacetylethylenediamine system has proved to be the bleaching system of choice in chlorine-free dishwashing detergents.
Optimum cleanliness even with stubborn tea stains is achieved whilst safeguarding the environment in the best possible manner.
At the same time active oxygen bleaching enables enzymatic systems to be used for optimal stain removal.
Sodium disilicate 20–30%
Trisodium citrate dihydrate 25–35%
Sodium carbonate 5–15%
Sodium percarbonate 5–15%
Tetraacetylethylenediamine 2–6%
Surfactant 1–2%
Polyacrylate 6–8%
Protease 1–2%
Amylase 1–2%
Tetraacetylethylenediamine [%]
Optimized dishwashing formulations
Tetraacetylethylenediamine has proved to be the bleaching system of choice in chlorine-free dishwashing detergents.
Optimum cleanliness even with stubborn tea stains is achieved whilst safeguarding the environment in the best possible manner.
At the same time active oxygen bleaching enables enzymatic systems to be used for optimal stain removal.
High cleaning performance due to Tetraacetylethylenediamine
The Tetraacetylethylenediamine system displays optimum activity in the temperature range of 45–65°C.
Tetraacetylethylenediamine concentrations of at least 2% are recommended.
Parallel to the bleaching performance, the reactivity of the dishwashing detergent towards microorganisms is increased as the Tetraacetylethylenediamine concentrations increase.
Tetraacetylethylenediamine in anhydrous liquid detergents
Conventional liquid detergents (heavy-duty liquids, HDL) have several advantages compared to products in powder form.
They are simpler to dispense, they do not produce dust when handling, and they dissolve quickly and entirely at the beginning of the washing process.
As a result of the high surfactant content, they are particularly effective against stains containing oil and at low temperatures.
Since they do not contain any bleaching system, they have disadvantages, however, with certain types of stains, which can only be counterbalanced in part by the use of enzymes or sequestering agents.
Tetraacetylethylenediamine is unstable in storage in aqueous formulations, but appropriate stability can be achieved in anhydrous liquid formulations.
The new type of anhydrous liquid detergents contains citrate or phosphate as the builder system.
This is suspended with 3–7% Tetraacetylethylenediamine and 8–15 % of a persalt in finely dispersed form in mixtures of surfactants and polyethylene glycols.
Additives to suppress the gel formation and to ensure flowability is recommended.
Tetraacetylethylenediamine granules can be obtained commercially for this application.
The high surfactant concentration makes a lower dosage of the product possible, and its high density reduces the packaging.
The bleaching results of anhydrous heavy-duty liquids containing Tetraacetylethylenediamine are comparable to those of compact detergents in powder form and superior to conventional heavy-duty liquids.
Anhydrous formulations enable the use of the Tetraacetylethylenediamine system.
Tetraacetylethylenediamine is only stable in anhydrous HDL formulations since i n the presence of water, hydrolysis or per hydrolysis occurs immediately with the decomposition of the bleaching system.
There is good stability in storage in anhydrous formulations.
Good washing results with low dosages
Liquid detergents with Tetraacetylethylenediamine bleaching system are comparable in performance to conventional powder heavy duty detergents and clearly superior to conventional liquid detergents. Their highly concentrated ingredients contribute in addition towards safeguarding the environment.
Tetraacetylethylenediamine in textile bleaching
Sodium hypochlorite and sodium chlorite are important bleaching agents in the textile industry.
They are coming increasingly under discussion, however, in connection with the growing AOX problems.
Neither the use of peracetic acid –because of technical problems (instability, odor) –nor its production in situ from acetic anhydride and hydrogen peroxide in the presence of an acid catalyst were successful alternatives.
The heat of the reaction, which is released, and the formation of diacyl peroxide as a byproduct make the reaction challenging to control.
The choice of Tetraacetylethylenediamine / hydrogen peroxide as the bleaching system is offered as an alternative.
It can be used in the pad batch impregnating bleaching and pad steam process.
Although bleaching is possible in an acid medium, the best results are obtained in the neutral to weakly alkaline range.
The Tetraacetylethylenediamine system offers the following advantages compared to conventional textile bleaching processes:
The fibers are only damaged insignificantly due to the gentle pH value.
Catalytic damage to the fibers only plays a secondary role.
The cotton has a supple, soft feel since waxes and fats remain on the fiber.
The use of colored fabrics is possible, as many dyes have less tendency to fade and bleed under these conditions.
The gentle process is also suitable for bleaching regenerated cellulose.
Bleaching temperatures <60°C make it possible to save energy.
With pad batch bleaching the maximum bleaching performance of the Tetraacetylethylenediamine / hydrogen peroxide system is in the neutral to the weakly alkaline range, preferably between pH 7 and 8.5 at temperatures of 50°C.
The cellulose fiber is swollen only a little under these conditions and can be damaged only minimally by the bleaching system.
Impregnating bleaching can be carried out both for a longer period (18 hours) at room temperature and also by steaming for a short time (15 min. / 99.5°C).
While an optimum pH value of 7.5 is shown for cold bleaching, a maximum degree of whiteness is obtained at pH 10 with hot bleaching.
With the two-stage pad steam process, an optimum between the degree of whiteness and damage to the fibers has to be found.
Here the Tetraacetylethylenediamine system can replace the hypochlorite completely.
So in the first stage, for example, the textiles can be padded and steamed with Tetraacetylethylenediamine / hydrogen peroxide, and subsequently, the peroxide bleaching can be carried out in an alkaline medium (pH 11.5–12.5).
Because Tetraacetylethylenediamine is partly used in high concentrations for textile bleaching, it should be remembered that the activator is only moderately soluble in water at room temperature. However, the solubility increases in the range between 40 and 50°C.
One part by weight of hydrogen peroxide (100%) can activate 3.4 parts by weight Tetraacetylethylenediamine.
In practice, it is advisable to work with an excess of hydrogen peroxide.
The Tetraacetylethylenediamine system in the pad batch
bleaching
Pad batch bleaching can be carried out under
both acid and alkaline conditions. Optimum bleaching
results with minimal fiber damage are observed
at 50°C in the neutral to weakly alkaline range.
The Tetraacetylethylenediamine system in impregnating bleaching
The use of the Tetraacetylethylenediamine system proves advantageous both for cold bleaching and also for hot bleaching.
The pH value, which influences both the degree of whiteness and also the fiber damage, is of particular importance in this case.
The Tetraacetylethylenediamine system in the two-stage pad steam bleaching
In the two-stage pad steam bleaching process, the stage of the chlorine bleaching can be replaced without any problems by activated Tetraacetylethylenediamine bleaching.
Advantages regarding the fiber damage result if peroxide bleaching is carried out first, followed by Tetraacetylethylenediamine bleaching.
Tetraacetylethylenediamine under cold wash conditions
Washing processes and washing conditions differ throughout the world.
Whereas washing by hand in the river with the aid of soap is common in many countries, automatic washing machines with multifunctional programs and built-in dryers are used in highly industrialized countries. Habits typical for a particular country are the temperature and length of a washing process.
In many regions, such as North America and the Far East, much lower temperatures and shorter washing times are used in comparison to Europe.
In order to obtain an optimum result, the laundry is often soaked over night and not washed until the next day.
The lower washing temperatures make it impossible in many countries to replace the ecologically harmful chlorine bleaching liquor by a persalt alone.
The reactivity of hydrogen peroxide is not sufficiently effective under these conditions.
On the other hand persalts have the advantage that they can be incorporated directly into a washing powder and the separate dosing stage can therefore be omitted.
The use of a persalt activator is essential to activate the bleach.
In this case Tetraacetylethylenediamine can be used either alone or combined with other low temperature activators.
Under cold wash conditions visible improvements in the bleaching results are possible over the whole temperature range between 10 and 40°C by using the Tetraacetylethylenediamine.
4–8% Tetraacetylethylenediamine combined with 6–12% perborate monohydrate or percarbonate have proved effective in compact detergents, whilst 10–15% Tetraacetylethylenediamine are expedient in bleach boosters.
The perhydrolysis of the Tetraacetylethylenediamine system is very fast even at 20°C, however the reactivity of the peracetic acid formed depends on the washing temperature and the reaction time. The bleaching result can be improved significantly, if Tetraacetylethylenediamine is already added in the soaking stage.
It is able to develop its full bleaching power as a result of the length of time.
Reference is made to the section on bleach boosters regarding the optimization of the bleach booster formulations.
The Tetraacetylethylenediamine system can be used in all powder detergents, irrespective of the type of builder system used, in bleach boosters and pre-soaking powders.
Incorporation in synthetic bar soaps is possible.
Tetraacetylethylenediamine granules have proved successful in many countries of the world.
Even under extreme climatic conditions they ensure good stability in storage and compatibility with other detergent ingredients and guarantee optimum bleaching combined with maximum sterilization.
Tetraacetylethylenediamine in all purpose cleaners
The incorporation of the Tetraacetylethylenediamine system in all kinds of anhydrous all-purpose cleaners in powder form does not present any problems.
In this field of application in particular, the antimicrobial effectiveness towards numerous germs is valued in addition to the excellent bleaching action.
Tetraacetylethylenediamine Production, toxicology, and environmental behavior
Tetraacetylethylenediamine has been produced from acetic anhydride and ethylenediamine since 1978 according to a method making economical use of resources.
By recycling all the partial streams, the plant guarantees integrated environmental protection and the uniformly high quality of the product with purity >99%.
The continuous, computer-controlled process makes the optimum use of both raw materials possible.
Direct coupling products are not produced.
The reaction water formed during the reaction – contaminated with traces of acetic acid – can be taken to the biological wastewater treatment plant without any problems. Organic distillation residue obtained in small amounts is burned and used to produce energy.
Numerous toxicological studies and decades of consumer experience emphasize the toxicological safety of raw materials in processing and use.
Tetraacetylethylenediamine does not have any labeling requirements.
By contrast with other detergent raw materials, such as surfactants, Tetraacetylethylenediamine changes during the washing process.
According to the reaction mechanism, it is converted into diacetyl ethylenediamine (DAED) with the release of peracetic acid and reaches the effluent in this form.
The tests conducted on both Tetraacetylethylenediamine and DAED prove that the two substances are not expected to cause any harm to humans or nature.
Both are readily biodegradable, compatible with water organisms, and were classified as harmless by the “Hauptausschuß Detergentien.”
In particular, when combined with sodium percarbonate, Tetraacetylethylenediamine represents an ecologically friendly bleaching system, the constituents of which are mineralized wholly and quickly.
The occurrence of stable metabolites was not observed during the degradation of Tetraacetylethylenediamine and DAED.
Industrial production of Tetraacetylethylenediamine
Tetraacetylethylenediamine is produced in a two-stage process from ethylenediamine (ED) and acetic anhydride (Ac2O).
Ethylenediamine is first reacted with acetic acid (AcOH) to form diacetyl ethylenediamine (DAED).
The reaction water formed is taken to the biological wastewater treatment plant.
In the second stage, DAED is subsequently converted with Ac2O via the stage of triacetylethylenediamine (TriAED) into Tetraacetylethylenediamine.
This is crystallized out of the reaction mixture, filtered, washed, dried, and granulated if necessary.
