2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium acetate

Endpoint summary

Additional information

Environmental Fate

Basic Yellow 28 acetate is only stable in presence of significant concentrations of free acetic acid; it cannot be isolated as such. The test substance is an aqueous solution in 40% acetic acid. Basic Yellow 28 acetate has a very high solubility in acetic acid solution; the commercial form is a ca 40% preparation (400 g/L) of Basic Yellow 28 acetate. Basic Yellow 28 methyl sulfate has a solubility of about 8.8 g/L, which means that the solubility of Basic Yellow 28 acetate is likely to decrease slightly with dissolution of the acetic acid solution.

The substance is stable at high temperatures and acidic and neutral pH as can be seen in the UV/Vis Spectrum at different pHs. At basic pH > 10, the Carbinol base ((2S)-2-{(E)-[2-(4-methoxyphenyl)-2-methylhydrazinylidene]methyl}-1,3,3-trimethyl-2,3-dihydro-1H-indol-2-ol) precipitates, from which Basic Yellow 28 acetate was formed by dissolving in acetic acid.

Basic Yellow 28 as the methyl sulfate salt has a low volatility (3.3E-7 hPa at 25°C) and should therefore not be released into air. According to its low log Kow, a low affinity for soil / sediment and consequently a compartmentalization into water compartments would be expected after release to the environment. However, due to its positive charge, Basic Yellow 28 is likely to adsorb rapidly onto any anionic structures and therefore to be removed quickly from the environment.

Due to its toxicity for aquatic organisms, all of its uses take place in closed systems and effluents containing the substance are not released into wastewater without specific aftertreatment.

A Level III fugacity model was conducted in the US EPA EPISUITE which assumes steady-state but not equilibrium conditions. The Level III model in EPI Suite predicts partitioning between air, soil, sediment and water using a combination of default parameters and various input parameters. This model has been used to calculate the theoretical distribution of the highest % component substance between four environmental compartments (air, water, soil, sediment) at steady state in a unit world.

Partitioning is detailed to be:

-    Air                1.33E-5%

-    Water           6.71%

-    Soil               78.6%

-    Sediment      14.7%

 

According to this modeling, the majority of the substance distributes to the soil and sediment compartments within the model which is probably due to its cationic nature, although the high solubility in water indicates that the substance is more likely to distribute to water.

Basic Yellow 28 displays slow biodegradability (ca 26% biodegradability) according to its BOD/COD ratio, < 10% DOC removal in an test for inherent biodegradability, and a QSAR evaluation (Does Not Biodegrade Fast (BIOWIN v4.10)). According to known substance data, thesubstance is stable at high temperatures and acidic and neutral pH. At basic pH > 10, the Carbinol base ((2S)-2-{(E)-[2-(4-methoxyphenyl)-2-methylhydrazinylidene]methyl}-1,3,3-trimethyl-2,3-dihydro-1H-indol-2-ol), which has a low solubility precipitates. Consequently, the substance is considered to be persistent in the environment. Due to its positive charge,Basic Yellow 28 adsorbs rapidly to anionic structures which leads to a removal from the environment.

Studies on direct phototransformation in water are not available but it is assumed on the basis of chemical structure and nature of use that the substance is not degraded by direct photolysis.

Basic Yellow 28 has a log Kow of < -1.1. This value indicates that possible bioaccumulation in the food chain is not anticipated. This is confirmed by the results of modeling by BCFBAF v3.01 of the EpiSuite Module, which gave an estimated Log BCF of 0.5.

Adsorption to soil is deemed to be low, based on the very low partition coefficient value and high water solubility. However, due to its positive charge, Basic Yellow 28 is likely to adsorb rapidly onto any anionic structures and therefore to be removed quickly from the environment.