2-Propenoic acid, γ-ω-perfluoro-C8-14-alkyl esters

Hydrolysis

Description of key information

Two Key studies according OECD 111 were performed with the pure cut fluorotelomere acrylate 8:2 (AC 800) and 10:2 (AC 1000).

The test item Fluowet AC 800 showed only moderate elimination at all tested conditions.

The test item Fluowet AC 1000 showed no hydrolysis at the environmental typical temperatures of 20 and 30 °C at pH 4, no hydrolysis at the environmental typical temperatures of 20 °C at pH 7 and 9 and only slight hydrolysis at pH 1.2 and 37 °C. At the elevated temperature of 50 °C moderate elimination of Fluowet AC 1000 was observed.

A supporting study with the degradation product 8: FTOH shows the following results: the test substance is stable under the conditions of the test at pH 4, 7 and 9 at 50 °C and pH 1.2 at 37 °C. The time in which 50 % of the test substance will transform is estimated as greater than one year: t1/2 > 1 year

Additional information

Key study with 8:2 fluorotelomer acrylate

Hydrolysis as a function of pH was determined according to OECD Guideline No. 111 and Council Regulation (EC) No. 440/2008, Method C.7 for the test item Fluowet AC 800 from 2012-11-06 to 2013-04-23 atDr.U.Noack-Laboratorien, 31157 Sarstedt, Germany.

Analyses of the test item were performed via GC-MS on a Rtx-1301 capillary column using an external standard. The method was validated with satisfactory results in regard to linearity, accuracy, precision and specificity.

The study was conducted with a test item concentration of 1000 µg/L in buffer solution pH 1.2 at a temperature of 37 °C and in buffer solutions of pH 4, 7 and 9 at temperatures of 20, 30 and 50 °C, respectively. Acetonitrile was used as co- solvent at a content of 10 % (v/v), as the test item was not readily soluble in the test system at the required test concentration. Samples were taken at test start (0 h) and at 12 to 15 spaced points until test end. Buffer solutions were analysed at test start and test end and there was no analytical interference with the test item.

Reaction rate constants and half-lives were calculated from the analysed samples and are presented in Table 1. The test item Fluowet AC 800 showed only moderate elimination at all tested conditions.

Analysis of the expected primary transformation product 2-(Perfluorooctyl)ethyl alcohol (8:2 FTOH) could not be performed within this study due to the complexity of the analysis. Nevertheless, samples for determination of this transformation product were taken, stored and analyses will be performed in a separate study as soon as an adequate analytical method will be available. The secondary transformation product PFOA could not be determined above the limit of quantification (LOQ_M, 2 µg/L) and was therefore regarded as not relevant.

Reaction Rate Constants and Half-lives ofFluowet AC 800

	pH 1.2	pH 4			pH 7			pH 9
	37 °C	20 °C	30 °C	50 °C	20 °C	30 °C	50 °C	20 °C	30 °C	50 °C
Reaction rate constantkobs [1/s]	1.00 x 10^-6	9.25 x 10^-7	1.70 x 10^-6	1.36 x 10^-6	5.92 x 10^-7	1.20 x 10^-6	9.72 x 10^-7	8.58 x 10^-7	1.60 x 10^-6	2.04 x 10^-6
Half-lifeT½[h]	193	208	114	142	325	160	198	224	120	94.4
Half-lifeT½[d]	8.04	8.67	4.73	5.92	13.5	6.67	8.25	9.33	5.00	3.93

Key study with 10:2 fluorotelomer acrylate

Hydrolysis as a function of pH was determined according to OECD Guideline No. 111 and Council Regulation (EC) No. 440/2008, Method C.7 for the test item from 2012-10-09 to 2013-04-19 atDr.U.Noack-Laboratorien, 31157 Sarstedt, Germany.

Analyses of the active ingredient of the test item were performed via GC-MS on a Rtx-1301 capillary column, using an external standard. Analyses of the transformation product perfluorodecanoic acid (PFDA) were peformed via LC-MS/MS on a silica based C18 reversed phase column, also using an external standard. Both methods were validated with satisfactory results in regard to linearity, accuracy, precision and specificity

The study was conducted with a test item concentration of 1000 µg/L in buffer solution pH 1.2 at a temperature of 37 °C and in buffer solutions of pH 4, 7 and 9 at temperatures of 20, 30 and 50 °C, respectively. Acetonitrile was used as co- solvent at a content of 10 % (v/v), as the test item was not readily soluble in the test system at the required test concentration. Samples were taken at test start (0 h) and at 12 to 13 spaced points until test end. Buffer solutions were analysed at test start (only GC) and test end and there was no analytical interference with the test item.

At environmental typical temperatures the test item Fluowet AC 1000 showed no significant hydrolysis. At elevated temperatures a increasing instability was observed to higher pH values.

Analysis of the expected primary transformation product 2-(Perfluorodecyl)ethyl alcohol (10:2 FTOH) could not be performed within this study due to the complexity of the analysis. Nevertheless, samples for determination of this transformation product were taken, stored and analyses will be performed in a separate study as soon as an adequate analytical method will be available. The secondary transformation product PFDA could not be determined above the limit of quantification (LOQ, 2 µg/L) and was therefore regarded as not relevant.

Reaction Rate Constants and Half-lives ofFluowet AC 1000

	pH 1.2	pH 4			pH 7			pH 9
	37 °C	20 °C	30 °C	50 °C	20 °C	30 °C	50 °C	20 °C	30 °C	50 °C
Reaction rate constantkobs [1/s]	6.83 x 10^-8	n.a.		1.80 x 10^-7	n.a.	1.48 x 10^-7	5.58 x 10^-7	n.a.	1.84 x 10^-7	1.72 x 10^-6
Half-lifeT½[h]	2818			1070		1303	345		1049	112
Half-lifeT½[d]	117			44.6		54.3	14.4		43.7	4.67

Supporting study with 8:2 FTOH

The aqueous stability of the test substance in sterile aqueous solutions buffered at pH 1.2, 4.0, 7.0 and 9.0 was determined. Test systems consisted of the test substance in aqueous buffered solutions in sterilized containers. The test system was incubated in the dark at 50°c at pH 4, 7 and 9 and at 37°C at pH 1.2.

The test substance isstable under the conditions of the test at pH 4, 7 and 9 at 50°C and pH 1.2 at 37°C. The time in which 50% of the test substance will transform is estimated as greater than one year:

t_1/2> 1 year.