cis-4-[3-(p-tert-butylphenyl)-2-methylpropyl]-2,6-dimethylmorpholine

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04.1987 - 08.1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: EPA Standard Evaluation Procedure; Report No.: EPA-540/9-85-013 (1985)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA Guideline Subdivision N 161-1 (Hydrolysis)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

cis-4-[3-(p-tert-butylphenyl)-2-methylpropyl]-2,6-dimethylmorpholine

EC Number:

266-719-9

EC Name:

cis-4-[3-(p-tert-butylphenyl)-2-methylpropyl]-2,6-dimethylmorpholine

Cas Number:

67564-91-4

Molecular formula:

C20H33NO

IUPAC Name:

(2R,6S)-4-[3-(4-tert-butylphenyl)-2-methylpropyl]-2,6-dimethylmorpholine

Details on test material:

IUCLID4 Test substance: other TS: 14-C Fenpropimorph

Specific details on test material used for the study:

Präparat-Nr. 65/17; specific radioactivity of the phenyl-U-14C-labelled substance: 166.69 MBq/g (purity >98%)

Radiolabelling:

yes

Study design

Analytical monitoring:

yes

Buffers:

Buffer solutions were prepared for each pH-value from deionized water which was cleaned prior to use by pumping through a column (25 cm x 3 cm) filled with charcoal. The following solutions were used:
pH 3.0 - 1 mM potassium hydrogen phthalate
pH 5.0 - 1 mM sodium acetate
pH 7.0 - 1 mM sodium phosphate
pH 9.0 - 1 mM boric acid; 1 mM sodium chloride

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 100 ml glass flasks with glass stoppers, containing 60 ml buffer and 600µl of the diluted stock solution
- Sterilisation method: Buffer solutions were sterilized for 20 min at 121°C by auto-claving

- Measures to exclude oxygen: After cooling down to RT argon was bubbled through the solutions for 10 min for replacing oxygen in order to avoid oxidation and/or radical- reactions.
- If no traps were used, is the test system closed/open: flasks with glass stoppers
- Is there any indication of the test material adsorbing to the walls of the test apparatus? The radioactive material was partially adsorbed to the glass vessels. It was redissolved by rinsing with dichloromethane or traced as 14C-carbondioxide after oxidation. Further radioactive material was adsorbed to the glass stopper of the flasks and could also be redissolved with dichloromethane.

OTHER TEST CONDITIONS
- Adjustment of pH: The pH was measured with a pH- meter (Metrohm E 500; for adjustment see attachment 7.2.) and titrated (with 0.1 M HCl or 0.1 M NaOH) to the desired pH before filling up to the required volume.

Duration of test

Duration:

32 d

Temp.:

25 °C

Initial conc. measured:

0.93 other: ppm

Results and discussion

Transformation products:

no

Total recovery of test substance (in %)

Total recovery of test substance (in %) 1

% Recovery:

103.2

pH:

3

Temp.:

25 °C

Duration:

32 d

Total recovery of test substance (in %) 2

% Recovery:

102.6

pH:

5

Temp.:

25 °C

Duration:

32 d

Total recovery of test substance (in %) 3

% Recovery:

83.6

pH:

7

Temp.:

25 °C

Duration:

32 d

Total recovery of test substance (in %) 4

% Recovery:

65.2

pH:

9

Temp.:

25 °C

Duration:

32 d

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

3

Temp.:

25 °C

DT50:

> 32 d

Type:

(pseudo-)first order (= half-life)

Dissipation DT50 of parent compound 2

pH:

5

Temp.:

25 °C

DT50:

> 32 d

Type:

(pseudo-)first order (= half-life)

Dissipation DT50 of parent compound 3

pH:

7

Temp.:

25 °C

DT50:

> 32 d

Type:

(pseudo-)first order (= half-life)

Dissipation DT50 of parent compound 4

pH:

9

Temp.:

25 °C

DT50:

> 32 d

Type:

(pseudo-)first order (= half-life)

Details on results:

The results of the hydrolysis study at 25°C are summarised in Table 1. At no pH-value hydrolysis products were detected by TLC-analyses. At neutral (pH 7) and alkaline (pH 9) pH values the recovery of the test substance decreased with time due to adsorption effects and the low solubility of the active substance at these pH values. A second peak (besides the test substance) in the TLC chromatograms of samples incubated at pH 3 could be characterised as the hydrochloride-adduct of fenpropimorph. In the rinsing solutions of the glass stoppers of the incubation flasks from solutions incubated at pH 9, besides fenpropimorph another compound was characterised by TLC co-chromatography. This compound had a Rf-value similar to the reference substance BF 421-13. An assessment of the concentration of this compound as a reasonable worst case calculation resulted in amounts up to 7.7% TAR. However, this substance is not considered as a hydrolysis product.

Any other information on results incl. tables

Table 1:  Recovery of radioactivity in % during hydrolysis of phenyl-U-^14C-labelled fenpropimorph (including rinsing solutions)
time (d)	pH 3	pH 5	pH 7	pH 9
0	114.1*	111.1*	105.9*	104.1*
1	108.2*	106.4*	108.9*	87.2
2	105.3*	102.9*	101.3*	91.5*
4	108.1	103.1	85.1	75.1
6	100.8	97.3	88.2	84.9
8	97.8	96.9	88.0	84.8
11	100.1*	98.3*	92.7*	88.7*
12	99.5*	94.7*	92.4*	91.1*
14	105.3	103.5	94.7	83.7
15	101.5	100.6	92.2	69.2
18	106.5	104.9	84.8	76.6
20	105.9	100.9	83.3	78.6
21	102.6	102.1	82.8	80.2
26	102.9	101.5	83.4	84.3**
32	104.1*	104.1*	86.6*	70.2*

*:          recovery in aqueous solution + rinsing solution from the glass flasks (6 ml dichloromethane)

**:        recovery in aqueous solution + rinsing solution of stoppers + radioactivity adsorbed on glass walls
             (determined as ¹⁴CO₂)

Applicant's summary and conclusion

Conclusions:

It can be concluded that fenpropimorph is hydrolytically stable in the whole investigated pH-range (pH 3 to pH 9) at 25°C. No half-lives were calculated.
No hydrolysis studies were carried out with metabolites, because no relevant metabolites appeared.