Reaction products of diazotized mixture of aniline, toluidines and xylidines coupled with mixture of aniline, toluidines and xylidines, subsequently diazotized then coupled with 2-naphthol

Endpoint summary

Description of key information

Solvent Red 24 Mix is a UVCB substance, mainly composed of three chemically defined constituents: Solvent Red 24 (CAS No. 85-83-6, composition percentage >85%), Solvent Orange 2 (CAS No. 2646-17-5, composition percentage <10%), and Solvent Yellow 14 (CAS No. 842-07-9, composition percentage <5%). More specifically, the constituent Solvent Red 24 was considered as the representative substance of the substance family 2-Naphthalenol, 1-[[4-(phenylazo)phenyl]azo]-, ar',ar''-Me derivatives (CAS No. 70879-65-1), the latter of which represents the overall major constituent (>85%) of the UVCB Solvent Red 24 Mix.The substance Solvent Red 24 is a mono-constituent substance with an expected concentration greater than 40% in 2-naphthalenol, 1-[[4-(phenylazo)phenyl]azo]-, ar',ar''-Me derivs., and with a concentration between 35 and 55% in the UVCB Solvent Red 24 Mix.

QSAR predictions for acute aquatic toxicity to fish, Daphnia, and algae were provided for the three main constituents of the UVCB. Overall, the estimated acute toxicity values were below the acute aquatic hazard classification threshold of 1 mg/L for the three taxonomic groups under analysis for all of the three main constituents of the UVCB substance Solvent Red 24 Mix.

It should also be noted that QSAR aquatic toxicity predictions for the main constituent Solvent Red 24 (CAS No. 85-83-6) were greater than the predicted water solubility of the compound itself, suggesting that an effect is not expected to occur in a saturated solution.

Based on the obtained QSAR predictions, conclusions for the UVCB target substance Solvent Red 24 Mix were derived following a weighted mean approach, where the percentage of composition of the three main constituents in the UVCB Solvent Red 24 Mix were taken into account. Hence, following the weighted mean approach, the acute toxicity values derived for each taxonomic group for the three constituents were found to be below the acute aquatic hazard classification threshold of 1 mg/L, as well as the calculated water solubility value for the UVCB target compound. A summary table is reported below:

Summary of the in silico predictions for ecotoxicological properties.

Name (CAS No.)	Concentration %	Endpoint/approach	Prediction (mg/L)	Reliability assessment	Adequacy
		ECOTOXICOLOGICAL PROPERTIES
Fish
Solvent Red 24 (85-83-6)	85%*	Aquatic toxicity, acute toxicity (fish), 96-hr LC50	0.043^a, b	Borderline Reliable	Adequate (Klimisch 2)
Solvent Orange 2 (2646-17-5)	10%		0.314^b	Moderate Reliable	Adequate (Klimisch 2)
Solvent Yellow 14 (842-07-9)	5%		0.597^b	Moderate Reliable	Adequate (Klimisch 2)
Solvent Red 24 Mix (UVCB)	--	Weighted mean approach, 96-hr LC50	0.098	--	--
Daphnia
Solvent Red 24 (85-83-6)	85%*	Aquatic toxicity, acute toxicity(Daphnia), 48-hr LC50	0.141^a, b	Borderline Reliable	Adequate (Klimisch 2)
Solvent Orange 2 (2646-17-5)	10%		0.525^b	Moderate Reliable	Adequate (Klimisch 2)
Solvent Yellow 14 (842-07-9)	5%		0.818^b	Moderate Reliable	Adequate (Klimisch 2)
Solvent Red 24 Mix (UVCB)	--	Weighted mean approach, 48-hr LC50	0.213	--	--
Algae
Solvent Red 24 (85-83-6)	85%*	Aquatic toxicity, toxicity(algae), 96-hr EC50	0.0045^a, b	Borderline Reliable	Adequate (Klimisch 2)
Solvent Orange 2 (2646-17-5)	10%		0.031^b	Moderate Reliable	Adequate (Klimisch 2)
Solvent Yellow 14 (842-07-9)	5%		0.058^b	Moderate Reliable	Adequate (Klimisch 2)
Solvent Red 24 Mix (UVCB)	--	Weighted mean approach, 96-hr EC50	0.0098	--	--

* *Concentration percentage of the main constituent Solvent Red 24 was adjusted from > 80% to 85% in order to reach a total composition percentage of 100% in the UVCB substance for the weighted mean calculation.

^aEstimated toxicity value above the predicted water solubility of the target constituent.

^bPrediction generated with ECOSAR.