Naphthenic acids, zinc salts

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7950 (Vapor Pressure)

Deviations:

no

GLP compliance:

yes

Type of method:

effusion method: isothermal thermogravimetry

Specific details on test material used for the study:

- Batch: A036/99 (Supplier batch number: SCC-1709-0300)
- Expiration date: 31 August 2018
- Storage condition of test material: Room temperature, protected from light

Temp.:

20 °C

Vapour pressure:

1.3 Pa

Remarks on result:

other: Volatile part of test item

Temp.:

25 °C

Vapour pressure:

1.9 Pa

Remarks on result:

other: Volatile part of test item

Temp.:

20 °C

Vapour pressure:

0.026 Pa

Remarks on result:

other: Other (non-volatile) part of the test item

Temp.:

25 °C

Vapour pressure:

0.035 Pa

Remarks on result:

other: Other (non-volatile) part of the test item

The test item is a mixture of components. Weight loss was observed at low temperatures and at high temperatures. Evaporation was observed at low temperatures and at higher temperatures. Vapour pressure was calculated for both ranges.

Low temperatures (range 40°C – 70°C)

The vapour pressure regression curve constructed using the data of Experiment 2 had a coefficient of correlation of < 0.99. The data for this Experiment was not used for the calculation of the vapour pressure in the range 40°C – 70°C. The vapour pressure regression curve of the log P_T of the test item as function of the reciprocal temperatures had an equation curve of:
log P_T= -2473´1/T + 8.56 (r = 0.992, n = 8).

Table 1. Results of the Vapour pressure Isothermal TGA Analysis

Experiment	Temperature [°C]	Weight loss [µg/min]	νT [g/cm^2/h]	logνT	logPT	PT [Pa]
1	40	2.81651	3.36 x 10^-4	-3.47	0.69	4.9
	50	4.04989	4.83 x 10^-4	-3.32	0.89	7.8
	60	6.98752	8.34 x 10^-4	-3.08	1.20	16
	70	9.34732	1.12 x 10^-3	-2.95	1.36	23
2^1	40	1.90283	2.27 x 10^-4	-3.64	0.47	3.0
	50	2.52434	3.01 x 10^-4	-3.52	0.63	4.3
	60	5.30431	6.33 x 10^-4	-3.20	1.04	11
	70	7.49220	8.94 x 10^-4	-3.05	1.23	17
3	40	2.53388	3.02 x 10^-4	-3.52	0.63	4.3
	50	4.08955	4.88 x 10^-4	-3.31	0.90	7.9
	60	6.62851	7.91 x 10^-4	-3.10	1.17	15
	70	8.52272	1.02 x 10^-3	-2.99	1.31	20

¹not used for calculation of the vapour pressure

Table 2. Vapour Pressure for volatile part of the test item

Temperature [°C]	logPT	PT [Pa]	PT [mm Hg]
20	0.13	1.3	1.0 x 10^-2
25	0.27	1.9	1.4 x 10^-2

 

Higher temperatures (range 200°C – 230°C)

The vapour pressure regression curve constructed using the data of Experiment 1 had a coefficient of correlation of < 0.99. The data for this Experiment was not used for the calculation of the vapour pressure in the range 200°C – 230°C. The vapour pressure regression curve of the log P_T of the test item as function of the reciprocal temperatures has equation curve of:
log P_T= -2230´1/T + 6.03 (r = 0.996, n = 8).

Table 3. Results of the Vapour pressure Isothermal TGA Analysis

Experiment	Temperature [°C]	Weight loss [µg/min]	νT [g/cm^2/h]	logνT	logPT	PT [Pa]
1^1	200	9.32893	1.11 x 10^-3	-2.95	1.36	23
	210	10.5845	1.26 x 10^-3	-2.90	1.43	27
	220	13.3540	1.59 x 10^-3	-2.80	1.56	36
	230	14.6929	1.75 x 10^-3	-2.76	1.61	41
2	200	8.77322	1.05 x 10^-3	-2.98	1.32	21
	210	9.96741	1.19 x 10^-3	-2.92	1.39	25
	220	12.0298	1.44 x 10^-3	-2.84	1.50	31
	230	14.1726	1.69 x 10^-3	-2.77	1.59	39
3	200	8.68246	1.04 x 10^-3	-2.98	1.32	21
	210	10.1961	1.22 x 10^-3	-2.91	1.41	25
	220	12.2676	1.46 x 10^-3	-2.83	1.51	32
	230	14.6121	1.74 x 10^-3	-2.76	1.61	40

¹not used for calculation of the vapour pressure

 

Table 4. Vapour Pressure of a major part of the Test Item

Temperature [°C]	logPT	PT [Pa]	PT [mm Hg]
20	-1.58	2.6 x 10^-2	2.0 x 10^-4
25	-1.45	3.5 x 10^-2	2.6 x 10^-4

 

Conclusions:

The vapour pressure of a volatile part of the test item, naphthenic acids, zinc salts was determined at 20°C and 25°C and found to be 1.3 Pa and 1.9 Pa, respectively. Vapour pressure of a non-volatile part of the test item, naphthenic acids, zinc salts, was determined at 20°C and 25°C and found to be 0.026 Pa and 0.035 Pa respectively.

Executive summary:

The vapour pressure of naphthenic acids, zinc salts was determined in a GLP-compliant isothermal TGA effusion method test, following OECD guideline 104 (CRL 2018). The study is considered relevant and reliable for use.

The vapour pressure of a volatile part of the test item, naphthenic acids, zinc salts was determined at 20°C and 25°C and found to be 1.3 Pa and 1.9 Pa, respectively. Vapour pressure of a non-volatile part of the test item, naphthenic acids, zinc salts, was determined at 20°C and 25°C and found to be 0.026 Pa and 0.035 Pa respectively. It was not possible to assign the measured vapour pressure values to individual constituents.

Description of key information

The vapour pressure of a volatile part of the test item, naphthenic acids, zinc salts was determined at 20°C and 25°C and found to be 1.3 Pa and 1.9 Pa, respectively. Vapour pressure of a non-volatile part of the test item, naphthenic acids, zinc salts, was determined at 20°C and 25°C and found to be 0.026 Pa and 0.035 Pa respectively. It was not possible to assign the measured vapour pressure values to individual constituents.

Additional information

The vapour pressure of naphthenic acids, zinc salts was determined in a GLP-compliant isothermal TGA effusion method test, following OECD guideline 104 (CRL 2018). The study is considered relevant and reliable for use. The vapour pressure of a volatile part of the test item, naphthenic acids, zinc salts was determined at 20°C and 25°C and found to be 1.3 Pa and 1.9 Pa, respectively. Vapour pressure of a non-volatile part of the test item, naphthenic acids, zinc salts, was determined at 20°C and 25°C and found to be 0.026 Pa and 0.035 Pa respectively. It was not possible to assign the measured vapour pressure values to individual constituents.

Naphthenic acids, zinc salts is a UVCB consisting of a large number of different constituents. Vapour pressure values have been predicted for representative structures within the UVCB. The vapour pressure QSAR study is assigned a reliability score of 2 (reliable with restrictions) as it is an accepted calculation method. The vapour pressure of the representative structures of zinc naphthenate were estimated with the QSAR model (MPVPBP) using the Modified Grain Method. The QSAR estimated vapour pressures of representative constituents of zinc naphthenate are in the range of 3.41 E-05 to 31.5 Pa.