Di-tert-butyl α,α,α',α'-tetramethyl-(p-phenylenedimethylene) diperoxide

Endpoint summary

Additional information

There is no data on 1,4-bis[1-(tert-butylperoxy)-1-methylethyl]benzene. A read across approach is proposed with 1,3 (or 1,4)-bis[1-(tert-butylperoxy)-1-methylethyl]benzene.

Water and sediment compartments

The hydrolysis of [1,3(or 1,4)-phenylenebis(1-methylethylidene)]bis[1,1-dimethylethyl] peroxide was evaluated in a study performed in accordance with OECD testing guideline 111 and EPA OPPTS 835.2110 under GLP requirements.

The results from the hydrolysis test indicate that 64.6, 71.4 and 77.3% of the reaction were observed after 5 days at pH 4, 7 and 9 solutions respectively, at 50 °C. The test has demonstrated that the substance is hydrolytically stable at pH 2.6 after 24 hours. The degradation rates were calculated using first order kinetics as follows:

 

At 50°C:

 

pH 4 : half-life = 7.9 d

pH 7: half-life = 10.3 d

pH 9: half-life = 13.4 d

 

Extrapolated values at 25°C, using the Arrhenius equation:

 

pH 4 : half-life = 56.4 d

pH 7: half-life = 74.7 d

pH 9: half-life = 96.5 d

 

 

The ready biodegradability of 1,3-bis[1-(tert-butylperoxy)-1-methylethyl]benzene was evaluated in a study performed in accordance with OECD testing guideline 301 D and GLP requirements (due to structural analogy, read-across from supporting substance is considered as valid, thus, results given here may apply to [1,3(or 1,4)- Phenylenebis(1-methylethylidene)] bis[tert-butyl] peroxide).

1,3-bis[1-(tert-butylperoxy)-1-methylethyl]benzene is not biodegraded in the closed bottle test, and therefore should not be classified as readily biodegradable. This lack of biodegradation is not due to toxicity of the test compound because the endogenous respiration is not inhibited by bis (tert-butyl peroxy isopropyl) benzene.

Sediment and water compartment exposition is likely. Besides, based upon the adsorption potential of the substance of interest, a study was conducted to determine the biodegradation of [1,3(or 1,4)-phenylenebis(1-methylethylidene)]bis[1,1-dimethylethyl] peroxide in water/sediment simulation test, according to US EPA guideline.

The substance was not found in the water layers at all time points. In the sediment layer, an average of 94.7% of the applied dose was detected at day 0. The substance has decreased to an average of 9.7% of the applied dose at day 90. The half-life in sediment/water compartment under anaerobic conditions was determined as 29 days.

Tert-butanol, the main expected breakdown product, was detected in water and sediment layers at all time point (except day 0) but below a quantifiable level until day 90: it represented an average of 61.5% of the test substance applied dose.

  

 

Soil compartments

Chemicals can reach the soil via several routes:

 

1. Application of sewage sludge in agriculture.

Organic peroxides, when released into the sewage of a plant production or of a downstream’s user plant, are treated with other substances in dedicated sewage treatment plants. The activated sludge stemmed from these sewage treatment plants are then extracted and treated as chemical waste

From the production plant, the release of organic peroxide into the sewage is very limited, not to say completely negligible. The waste water from production plant is usually treated: at least a physical/chemical treatment, which will neutralize potential residual organic peroxide, and that can be followed by a biological treatment. So it is expected that organic peroxides won’t be present in sludge.

Regarding the rest of the lifecycle, organic peroxides are mainly used as cross-linking agent/polymerization initiator for the production of resins/rubbers/polymers. Based upon the fact that organic peroxides are totally consumed during the process (>99%) and that those processes are water-free (so no production of sewage sludge), it is assumed that the soil is not exposed to organic peroxides via use of sludge.

As a consequence, we can assume that soil is not exposed to organic peroxides via the application of sewage sludge in agriculture.

 

2. Direct application of chemicals.

Based on the uses inventoried for organic peroxides we can consider that there is no direct application of these substances on the soil compartment. Hereunder, the relevant Environmental Release Categories (ERC), as described in guidance R12 (version 2.0, dated 7/11/2010)

 

3. Deposition from the atmosphere.

Deposition from the atmospheric compartment involves volatilization, vaporization or direct release of a considered substance into the atmosphere. Due to their dangerous intrinsic physico-chemical properties, organic peroxides are carefully handle in closed systems and their transport and production are ruled by several regulations. Based on organic peroxides uses too, we may assume that deposition on soil from the atmosphere is unexpected.

As exposure of the soil compartment is unlikely, we don't propose a simulation biodegradation tests in soil.