Reaction mass of Copper,di-µ-iodotris[triphenylphosphine]di- and iodobis(triphenylphosphino)copper

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

05/2018 to 10/2018

Reliability:

1 (reliable without restriction)

Principles of method if other than guideline:

Primary aim of the feasibility study was to establish an analytical method to quantify the starting substance Iodobis(triphenylphosphino)copper beside its assumed degradation products, Triphenylphosphine (TPP) (CAS 603-35-0) and Triphenylphosphine oxide (TPPO) (CAS 791-28-6).
The availability of a valid analytical method is a requirement for the performance of the test “hydrolysis as a function of pH” of the test item Iodobis(triphenylphosphino)copper (according to the OECD guideline for the testing of chemicals No. 111).
Parameters analysed / observed were: HPLC-UV/Vis analysis of concentrated samples and AAS analysis of HPLC fractions.

The main challenges within this study were:
- The low water solubilty of the starting substance Iodobis(triphenylphosphino)copper
- Similar retention times of the starting substance and TPP
- Similar UV/Vis absorbtion characterisitcs of the starting substance and TPP

GLP compliance:

no

Remarks:

preliminary study

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Bruggolen® H3301, Batch No.: 16101213, L. Brüggemann GmbH & Co. KG
- Expiration date of the lot/batch: 26.02.2019

Remark: The test material called "Iodobis(triphenylphosphino)copper" in the study report is idential to "Reaction mass of Copper,di-µ-iodotris[triphenylphosphine]di- and iodobis(triphenylphosphino)copper" (name used in the REACH dossier).

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

- 0.01 M acetate (pH 4)
- 0.01 M carbonate (pH 7)
- 0.01 M carbonate (pH 9)

Each solution was prepared with pure water.

Number of replicates:

2 replicates for each pH-values

Positive controls:

yes

Remarks:

test item, TPP and TPPO

Negative controls:

yes

Remarks:

AAS without test item

Preliminary study:

The feasibility study can be considered as a preliminary study since its aim was to quantify the test item and its proposed hydrolysis products triphenylphosphine (TPP) and triphenylphosphine oxide (TPPO).
Recovery rates of the test item can be found at: "Details on results", No. D.

Transformation products:

not measured

Remarks on result:

not determinable because of methodological limitations

Remarks:

Low recovery rate of test item in the analytical method applied (concentration and HPLC/UV-Vis), no analytical method available to quantify the test item besides its proposed degradation products.

Details on results:

A) HPLC-UV/Vis method development:
Iodobis(triphenylphosphino)copper and TPP could not be separated from each other (co-elution). The spectra of both substances are almost equal. Thus, an unequivocal characterisation of Iodobis(triphenylphosphino)copper and TPP could not be carried out. In case of TPPO, the retention time as well as the spectrum were different compared to Iodobis(triphenylphosphino)copper and TPP.


B) LC-MS method development:
The limitation of the LC-MS method was, that an analyte must be ionised to be detected. During method development a sufficient ionisation of Iodobis(triphenylphosphino)copper, TPP and TPPO could not be obtained. Moreover the mass transitions found were not specific and hence could not be used for characterisation. Thus, no further attempts were made for method development due to the properties of the analytes.


D) HPLC-UV/Vis analysis of concentrated samples in pure water and buffer solutions:
The concentration of the test item in the concentrated sample was measured by means of external standard calibration using HPLC-UV/Vis analysis. Procedural recoveries were calculated for each sample based on the nominal concentration. The procedure was considered valid if recoveries were in the range of 70-110% of the nominal concentration.

For characterisation (specificity) of the test item and its transformation products (TPP, TPPO) retention times of the analyte peak from standards and sample solutions were compared (co-chromatography).

Results are summarized in a tabular form (see: "Any other information on results incl. tables").
Procedural recoveries were 66% and 62% of the nominal concentration for pure water, 76% and 74% at pH 4, 59% and 52% at pH 7 and 50% and 49% at pH 9.
Valid results were obtained for samples at pH 4.
In case of pure water, results were slightly below the designated range.
Negligible amounts of the test item remained in the vessel after the sample was removed. Procedural recoveries in the rinsing solution (ACN) were < 6% of the nominal concentration.
Recoveries < 70% of the nominal concentration could be due to a volatilisation during sample preparation or because of a hydrolysis reaction in the respective solution. An evidence for the latter was the occurrence of TPPO in each tested sample.


E) AAS analysis of fractionated samples:
The determination of copper was carried out by means of AAS (atomic absorption spectroscopy). The fraction was concentrated by a factor of 10.
Copper was found in the fraction indicating that a portion of the test item remained stable during analysis and thus the signal found during HPLC-UV/Vis analysis could consist of both the test item and TPP.

Procedural recoveries after sample concentration

Sample	Concentration nominal after sample concentration [mg/l]	Concentration found [mg/l]	Procedural recovery [%]
pure water (ACN/H20 50:50)	10.190	6.743	66.2
	10.190	6.297	61.8
pure water (ACN)	10.190	0.360	3.5
	10.190	0.456	4.5
pH 4  (ACN/H20 50:50)	10.190	7.725	75.8
	10.190	7.497	73.6
pH 4  (ACN) (vessel rinsing)	10.190	0.528	5.2
	10.190	0.613	6.0
pH 7  (ACN/H20 50:50)	10.190	5.961	58.5
	10.190	5.324	52.2
pH 7  (ACN)  (vessel rinsing)	10.190	0.410	4.0
	10.190	0.389	3.8
pH 9  (ACN/H20 50:50)	10.190	5.075	49.8
	10.190	5.029	49.4
pH 9  (ACN)  (vessel rinsing)	10.190	0.362	3.6
		< LOD	-

Validity criteria fulfilled:

not applicable

Conclusions:

An unequivocal determination of Iodobis(triphenylphosphino)copper and its potential transformation products TPP and TPPO was techincally not feasible (using HPLC/UV-Vis, LC-MS and AAS) and thus the study “hydrolysis as a function of pH” (according to the OECD guideline for the testing of chemicals No. 111) could not be carried out.

However, the performed tests indicated an instability of the test item in aqueous solutions at different pH values.

Executive summary:

The purpose of this study was to evaluate the feasibility of the test “hydrolysis as a function of pH” of the test item Iodobis(triphenylphosphino)copper (according to the OECD guideline for the testing of chemicals No. 111).

Different analytical methods were tested to characterise and quantify the test item and its proposed hydrolysis products triphenylphosphine (TPP) and triphenylphosphine oxide (TPPO).

LC-MS analysis was not feasible due to the test item properties.

For HPLC-UV/Vis analysis samples had to be concentrated due to the sensitivity of the analytical method and the low water solubility of the test item. Procedural recoveries using spiked samples were calculated for the concentration process.

Valid results were obtained for samples at pH 4.

In case of pure water results were slightly below the designated range of 70-110% of the nominal concentration.

In terms of samples at pH 7 and 9 recoveries were in the range of 49-59% of the nominal concentration.

Recoveries < 70% of the nominal concentration could be due to a volatilisation during sample preparation or because of a hydrolysis reaction in the respective solution. An evidence for the latter was the occurrence of TPPO in each tested sample.

In conclusion, the performed tests indicated an instability of the test item in aqueous solutions at different pH. However, an unequivocal determination of Iodobis(triphenylphosphino)copper and its potential transformation products TPP and TPPO was techincally not feasible and thus the study “hydrolysis as a function of pH” (according to the OECD guideline for the testing of chemicals No. 111) could not be carried out.

Reference 2

Endpoint:

hydrolysis

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Study period:

01/2018 to 10/2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Justification for type of information:

Considering the structural similarities of "Reaction mass of Copper,di-µ-iodotris[triphenylphosphine]di- and iodobis(triphenylphosphino)copper" and "Iodo(triphenylphosphino)copper" and the almost identical physical and chemical properties, especially molecular weights, partition coefficients and water solubilites, it can be expected that these substances will show quite similar behaviour with respect to hydrolysis.

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

The purpose of this study was to investigate the extraction behavior of iodo(triphenylphosphino)copper (1:1 Copper Complex) from polyamide 6.6 compounds, and the degradation/hydrolysis of iodo(triphenylphosphino)copper complex in polyamide 6.6 (PA 6.6) compounds in an aqueous environment as an indication of the hydrolytically behavior of iodo(triphenylphosphino)copper. The degradation/hydrolysis products in the extraction media were analyzed by HPLC / AAS.

The study was conducted to determine the possible release of iodo(triphenylphosphino)copper and the release of degradation products into the environment.

Therefore, compounds with 0.3% (w/w) additive BRUGGOLEN® H3336 (containing 25% iodo(triphenylphosphino)copper) were prepared and the polymer granules were stored in demineralized water under different conditions (time and temperature). Afterwards, the extraction solutions were analyzed by means of HPLC and AAS.

GLP compliance:

no

Remarks:

extraction study

Specific details on test material used for the study:

Thermoplastic compounds with 0.3% (w/w) additive BRUGGOLEN® H3336 (containing 25% iodo(triphenylphosphino)copper) were prepared.

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

For AAS, 20 ml of the extraction solution were taken, acidified and analysed, for detailed AAS conditions, see: "Any other information on materials and methods incl. tables".
Additionally, samples from the extraction solution were analysed using HPLC, for detailed HPLC conditions, see: "Any other information on materials and methods incl. tables".

Details on test conditions:

50 g of Polyamide 6.6 (PA 6.6) granules (containing copper complex or not) were stored in 500 ml demineralised water for a defined period of time at a defined temperature.
After the storing period, samples were taken from the extraction solutions and analysed via HPLC and AAS.


Overall, four different experiments were performed:

a) Polyamide 6.6 (PA6.6) compound with copper-triphenylphosphine complex 1:1 (iodo(triphenylphosphino)copper) was stored under reflux (100 °C) for three days (1 l Erlenmeyer flask: 500 ml deionized water + 50 g polyamide compound granules).
b) Polyamide 6.6 (PA6.6) compound without copper-triphenylphosphine complex was stored under reflux (100 °C) for three days (1 l Erlenmeyer flask: 500 ml deionized water + 50 g polyamide compound granules) as a control.
c) Polyamide 6.6 (PA6.6) compound with copper-triphenylphosphine complex 1:1 (iodo(triphenylphosphino)copper) was stored at room temperature (RT; ca. 24°C) for 2 months (1 l Erlenmeyer flask: 500 ml deionized water + 50 g polyamide compound granules). The temperature during storage was recorded using a temperature logger.
d) Polyamide 6.6 (PA6.6) compound with copper-triphenylphosphine complex 1:1 (iodo(triphenylphosphino)copper) was stored at 50°C for 2 months (1 l Erlenmeyer flask: 500 ml deionized water + 50 g polyamide compound granules). The temperature was controlled using a thermo sensor.

Number of replicates:

One for each experiment a) to d).

Negative controls:

yes

Remarks:

Extraction of PA 6.6 compound without copper compound (experiement b))

Preliminary study:

The conducted extraction study was designed to examine the extraction of iodo(triphenylphosphino)copper (CAS 47107-74-4) from Polyamide 6.6 (PA 6.6) compounds under aqueous conditions (Study on hydrolysis/extraction).

Test performance:

Aqueous extracts of polyamide 6.6 compounds, containing iodo(triphenylphosphino)copper as a stabilising agent were examined on the presence of iodo(triphenylphosphino)copper, copper, triphenylphosphine (TPP) and triphenylphosphineoxide (TPPO).

Using HPLC and AAS, it could be shown, that both copper and triphenylphosphine oxide (TPPO) are released, but not iodo(triphenylphosphino)copper itself from polyamide 6.6 compounds containing iodo(triphenylphosphino)copper.

Transformation products:

yes

No.:

#1

No.:

#2

Details on hydrolysis and appearance of transformation product(s):

Details on experiments

a) Polyamide 6.6 (PA6.6) compound with copper-triphenylphosphine complex 1:1 (iodo(triphenylphosphino)copper) / 100 °C / three days
Observation of:
triphenylphosphine: no
triphenylphosphine oxide: yes
copper: yes
iodo(triphenylphosphino)copper: no


b) Polyamide 6.6 (PA6.6) compound without copper-triphenylphosphine complex / 100 °C / three days.
Observation of:
triphenylphosphine: no
triphenylphosphine oxide: no
copper: no
iodo(triphenylphosphino)copper: no


c) Polyamide 6.6 (PA6.6) compound with copper-triphenylphosphine complex 1:1 (iodo(triphenylphosphino)copper) / RT; ca. 24°C / 2 months
Observation of:
triphenylphosphine: no
triphenylphosphine oxide: yes
copper: yes (weak)
iodo(triphenylphosphino)copper: no


d) Polyamide 6.6 (PA6.6) compound with copper-triphenylphosphine complex 1:1 (iodo(triphenylphosphino)copper) / 50°C / 2 months
Observation of:
triphenylphosphine: no
triphenylphosphine oxide: yes
copper: yes
iodo(triphenylphosphino)copper: no

Remarks on result:

not measured/tested

Remarks:

quantitative determination of degradation was not within the scope of this study

Details on results:

Temperature of the extraction solution seems to have a significant influence of the amount of degradation products that are released. However, the influence of temperature was not examined quantitatively within this study, but only qualitatively.

Validity criteria fulfilled:

not applicable

Conclusions:

From the conducted experiments, it can be concluded, that polyamide 6.6 compounds, containing iodo(triphenylphosphino)copper as a stabilising agent, do release both copper and triphenylphosphine oxide (TPPO), but not iodo(triphenylphosphino)copper itself or triphenylphosphine.

Executive summary:

Release studies of polyamide 6.6 compounds containing iodo(triphenylphosphino)copper under different conditions (temperature and time) were conducted.

Polyamide 6.6. compounds with iodo(triphenylphosphino)copper containing additive (BRUGGOLEN® H3336) have been produced via extrusion on a twin-screw extruder.

The release of iodo(triphenylphosphino)copper from polyamide 6.6 compounds into the environment under aqueous conditions has been simulated.

Therefore, 50g of the polyamide 6.6. compounds in granular form have been stored in 500 ml water. Storage times were three days at 100°C and two months at room temperature and 50°C. The extraction solutions have been analyzed to determine the products available in the extraction solution via AAS and HPLC.

The previously described tests showed that storage of polyamide compounds containing the respective copper-triphenylphosphine complex as a stabilizer in an aqueous surrounding under different conditions (100°C - three days; RT - two months; 50°C - two months) leads to the release of the respective degradation/hydrolysis products triphenylphosphine oxide (TPPO) and copper only. Both the complex itself as well as the triphenylphosphine are not found in the extraction solutions. Consequently, the copper-triphenylphosphine complex hydrolyzes under aqueous conditions, since only its degradation/hydrolysis products TPPO and copper are found.

Description of key information

From the studies on hydrolysis conducted so far, it can be concluded, that "Reaction mass of Copper,di-µ-iodotris[triphenylphosphine]di- and iodobis(triphenylphosphino)copper"

hydrolyses in water:

It was shown that aqueous extraction solutions of articles containing

"Reaction mass of Copper,di-µ-iodotris[triphenylphosphine]di- and iodobis(triphenylphosphino)copper"

contain

both copper and triphenylphosphine oxide (TPPO) but neither

"Reaction mass of Copper,di-µ-iodotris[triphenylphosphine]di- and iodobis(triphenylphosphino)copper"

nor

triphenylphosphine.

However, the conduction of an OECD 111 study was not possible due to methodical limitations:

Low recovery rate of test item in the analytical method applied (concentration and HPLC/UV-Vis), no analytical

method available to quantify the test item beside its proposed degradation products.

The reasons for these difficulties are primarily:

- The low water solubility of the starting substance

"Reaction mass of Copper,di-µ-iodotris[triphenylphosphine]di- and iodobis(triphenylphosphino)copper"

- Similar retention times of the starting substance and TPP

- Similar UV/Vis absorbtion characterisitcs of the starting substance and TPP