Tetraacetylethylenediamine

• TAED
• N, N, N ', N'- tetraacetyl ethylene diamine
• N, N'- ethylenebis ( N- acetylacetamid )

Beige crystals

Fixed

149-154 ° C

Sparingly soluble in water (1 g / l at 20 ° C)

Template: Infobox chemical / molecular formula search available

Tetraacetylethylenediamine (TAED) is a tertiary amide, which is used as an activator of bleaching agents in detergents. Since TAED is not long -term stability in aqueous media, it is used exclusively as granules in solid and suspended in anhydrous liquid Detergentienzubereitungen.

Occurrence

Tetraacetylethylene is a commonly used component of various detergents. TAED part of a larger group of active uncharged N-and O -acyl compounds (such as tetraacetylglycoluril or glucose penta- acetate) and has its dominant market position with a total production of over 80,000 tons / year in Europe against the meantime developed anionic (eg, sodium nonanoyloxybenzenesulfonate NOBS ) and cationic (eg nitrile ) bleach activators claimed. Powdered Universal detergent for a share of 1-3% TAED, while detergent concentrates containing 4-6% and 6-8% TAED Compact detergent.

A high level of awareness among the population gained TAED in the expiring 1970s by a commercial of the OMO detergent, whose slogan read: " OMO, with TAED system".

Production

TAED is prepared in a two step process from ethylene diamine and acetic anhydride.

Equation (1 ) gives the symmetric diacetylated intermediate DAED. Reaction (2) at temperatures from 120 to 170 ° C with an excess of acetic anhydride to an equilibrium distribution between TAED, diacetylethylene ( DAED ) and Triacetylethylendiamin and produces undesirable dark brown impurities. To obtain a pure, white, odorless product, the reaction mixture is decolorized with activated carbon, the TAED is isolated by vacuum distillation or the washed, after cooling the mixture obtained in crystalline form TAED with acetic acid and water and dried. The scale by guided reaction proceeds almost quantitatively. The resulting in considerable amounts in the reaction, acetic acid may be purified by liquid-liquid extraction or distillation, and recycled into the production of acetic anhydride.

Properties

Because of unsatisfactory long-term stability of the powder into solid detergent compositions TAEDs it is granulated with the help of the sodium salt of carboxymethyl cellulose (Na - CMC), and the granules are sometimes also coated and blue or green colored. The granules dissolve despite the relatively low solubility in cold water of TAEDs (1 g / l at 20 ° C) because of its low concentration in the washing powder very quickly and completely in the wash liquor. TAED decomposes at the so-called perhydrolysis reaction with hydrogen peroxide in the percarbonate bleaching agent under conditions of a wash process (pH 10) already at 23 ° C to > 99% to DAED, which is relatively stable to hydrolysis but readily biodegradable. The peracetic acid formed has bactericidal, virucidal and fungicidal properties and rapidly destroyed > 99.99 % of microorganisms. Thus, the combination of TAED with percarbonate has a disinfecting and deodorizing.

Use

TAED acts as an activator in detergents, bleaching agents such as sodium perborate or sodium percarbonate. A bleaching effect of such peroxidic compounds comes without TAED into existence only at temperatures above 60 ° C. The use of TAED, however, enables bleaching at lower temperatures. This is due to the reaction between TAED ( 1) and the peroxide bleaching agent or hydrogen peroxide to form an intermediate which occur from N, N'- diacetylethylenediamine (2) and peroxyacetic acid (3):

This is due to their occurring even at room temperature decay with formation called singlet oxygen, a lively, highly reactive oxygen species, the actual bleach.

Relatively small amounts of TAED can also be used for the bleaching of paper and textiles and for the production of peracetic acid for disinfection purposes. Due to its disinfectant and deodorizing effect TAED / percarbonate combinations are used in dishwashing detergents and denture cleaners.

TAED is more effective in the removal of hydrophilic stains such as Tea, coffee and red wine. To hydrophobic stains such as Grass juice and spices ( Curry ), it is less effective. The washing process is pH controlled by appropriate additives in detergents, in order to enable the rapid and complete formation of peracetic acid from the TEAD at the beginning about pH 10. The resulting acetic acid lowers the pH, so that the degradation of most pads is accelerated. As a relatively mild oxidant attacks the TAED produced by exposure peracetic acid ( in contrast to the United States nor in widespread bleaching agent sodium hypochlorite) textile dyes and fibers to very little. At temperatures below 40 ° C, the action of TAED is unsatisfactory. However, none of the bleach activators previously described as active below 40 ° C has even come close to the well-balanced property profile of TAED.

In water-containing liquid detergent whose market volume steadily increasing worldwide, TAED is not stable and would also interact with the bleach. Attempts to separate them by compartmentation of TAED of water phase and bleach were, so far with little success.

Ecology

TAED is largely non-toxic and readily biodegradable. TAED and its precursor DAED have low aquatic ecotoxicity. TAED shows at all exposure routes very low toxicity, affects practically non- irritating to the skin and eyes and gives no evidence of skin sensitization. TAED is not mutagenic and not teratogenic.