Betaines, coco alkyldimethyl(3-sulfopropyl)

Vapour pressure

Administrative data

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

Vapour pressure

Melting point is between 200 and 300 °C, hence a limit value based on a recognised calculation method is sufficient according to REACH Annex VII, column 2.

1. SOFTWARE
EPIWIN software by US-EPA

2. MODEL (incl. version number)
MPBPVPWIN v1.43

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
The substance is a organic UVCB, the CAS number 68201-55-8 (EC 269-225-1) is associated with the inventory name Betaines, coco alkyldimethyl(3-sulfopropyl), CAS name Sulfobetaines, coco alkyldimethyl(3-sulfopropyl) and IUPAC name 3-[C8-18 (linear, even-numbered)-alkyl(dimethyl)ammonio]propane-1-sulfonate, and has the molecular formula C7H17NO3S·[CH2]8-16. As indicated by the name, there are several aliphatic moieties with varying chain lengths attached to the nitrogen of the inner salt, resulting in a variable composition. Below there are the possible individual components ordered by the carbon number of the side chain with approximate contents listed:

C8: 0-12%, [O-]S(=O)(=O)CCC[N+](C)(C)CCCCCCCC
C10: 0-10%, [O-]S(=O)(=O)CCC[N+](C)(C)CCCCCCCCCC
C12: 45-57%, CCCCCCCCCCCC[N+](C)(C)CCCS(=O)(=O)[O-]
C14: 14-28%, CCCCCCCCCCCCCC[N+](C)(C)CCCS(=O)(=O)[O-]
C16: 5-13%, CCCCCCCCCCCCCCCC[N+](C)(C)CCCS(=O)(=O)[O-]
C18: 4-12%, [O-]S(=O)(=O)CCC[N+](C)(C)CCCCCCCCCCCCCCCCCC

QSAR estimations are performed for all contained structure, but as the C12 variation is with approx. 50% the main constituent, special emphasis will be laid on the value derived for this structure, and the values for the C8 and C18 constituents will be regarded especially, too, as the cover both possible extremes and give hence and indication of the range of the estimated values.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- The complete test sets of experimental data for (melting point, boiling point and) vapour pressure can be downloaded via the Internet at: http://esc.syrres.com/interkow/EpiSuiteData.htm

5. APPLICABILITY DOMAIN
Estimation accuracy: The accuracy of MPBPWIN's "suggested" VP estimate was tested on a dataset of 3037 compounds with known, experimental VP values between 15 and 30 deg C (the vast majority at 25 or 20 deg C). The experimental values were taken from the PHYSPROP Database that is part of the EPI Suite. For this test, the CAS numbers were run through MPBPWIN as a standard batch-mode run (using the default VP estimation temperature of 25 deg C) and the batch estimates were compared to PHYSPROP's experimental VP. The plot clearly indicates that the estimation error increases as the vapour pressure (both experimental and estimated) decreases, especially when the vapour pressure decreases below 1x10-6 mm Hg (0.0001333 Pa).
The estimation methodology uses the normal boil point to estimate the liquid-phase vapour pressure. For solids, the melting point is required to convert the liquid-phase vapour pressure to the solid-phase vapour pressure. VP estimation error can be introduced by:
(1) poor Boiling Point estimates or values
(2) poor Melting Point estimates or values (for solids)

The 3037 compound test set contains 1642 compounds with available experimental Boiling points and Melting points. For this subset of compounds, the estimation accuracy statistics are (based on log VP):

number = 1642
r2 = 0.949
std deviation = 0.59
avg deviation = 0.32

These statistics clearly indicate that VP estimates are more accurate with experimental BP and MP data.

Estimation domain: The intended application domain is organic chemicals. Inorganic and organometallic chemicals generally are outside the domain.
Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that property estimates are less accurate for compounds outside the Molecular Weight range of the training set compounds, and/or that have more instances of a given fragment than the maximum for all training set compounds. It is also possible that a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed. These points should be taken into consideration when interpreting model results.
The complete training sets for MPBPWIN's estimation methodology are not available. Therefore, describing a precise estimation domain for this methodology is not possible. The current applicability of the MPBPWIN methodology is best described by its accuracy in predicting vapour pressure as described above in the accuracy section.

6. ADEQUACY OF THE RESULT
The results calculated for the single constituents of the organic substance Betaines, coco alkyldimethyl(3-sulfopropyl) seem reasonable. The test material melted between 250.5 and 254.5 °C under degradation. The vapour pressures were calculated using both the experimental and estimated melting points.
The estimated melting points range from 235.08°C (C8) to 289.28°C (C18), the melting point of the main component, i.e. the C12-derivative, matches with 256.76°C pretty good the experimentally determined melting point, i.e. between 250.5 and 254.5 °C while degradation occurs. So in general the model is considered suitable for the melting point estimation, and it can be reasonably concluded that it is suitable for vapour pressure estimation, too. The estimated vapour pressure values, derived from both estimated and determined melting points, range from 4.46E-12 Pa resp. 2.74E-12 Pa (C8) to 2.08E-16 Pa resp. 5.95E-16 Pa (C18), the vapour pressure of the C12 constituent lies with 8.59E-14 Pa resp. 9.69E-14 Pa in between.
Taking into account the magnitude of the vapour pressure result it is considered that the result clearly indicates that Betaines, coco alkyldimethyl(3-sulfopropyl) is not volatile.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Remarks:

Melting point

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

27th July 1995

Deviations:

no

GLP compliance:

no

Type of method:

capillary method

Key result

Melting / freezing pt.:

>= 250.5 - <= 254.5 °C

Decomposition:

yes

Decomp. temp.:

>= 250.5 - <= 254.5 °C

Remarks on result:

other: mean value of 2 measurements

Conclusions:

The study was performed according to OECD TG102 without deviations and therefore reliability of Klimisch 2 has been assigned. The test material melted between 250.5 and 254.5 °C under degradation.

Executive summary:

The melting point of the test substance was determined experimentally using the capillary method in a non-GLP test according to OECD guideline 102. A preliminary test and 2 measurements in the main test have been conducted. The test material melted between 250.5 and 254.5 °C under degradation.

Data source

Reference

Reference Type:

other: software application

Title:

US EPA. [2012]. Estimation Programs Interface Suite™ for Microsoft® Windows, v 4.10 . United States Environmental Protection Agency, Washington, DC, USA ; MPBPWIN™ Version 1.43

Author:

U.S. Environmental Protection Agency 1200 Pennsylvania Ave., N.W. (Mail Code 7406M) Washington, DC 20460

Year:

2018

Bibliographic source:

http://www.epa.gov/oppt/exposure/pubs/episuite.htm

Materials and methods

Test guideline

Guideline:

other:

Version / remarks:

REACH guidance on QSARs Chapter R.6 , May 2008

Principles of method if other than guideline:

The computer program MPBPWIN (v1.43) by US-EPA is used for this estimation. Vapour Pressure is estimated by three methods; all three methods use the boiling point.  The first is the Antoine method (see Chapter 14 of W.J. Lyman's book "Handbook of Chemical Property Estimation Methods", Washington, DC: American Chemical Society, 1990).  The second is the modified Grain method (see page 31 of Neely and Blau's Environmental Exposure from Chemicals, Volume I, CRC Press, 1985).  The third is the Mackay method (see page 31-2 of Neely and Blau's Environmental Exposure from Chemicals, Volume I, CRC Press, 1985).

GLP compliance:

no

Type of method:

other: QSAR estimation

Test material

Test material information

Constituent 1

Reference substance name:

Betaines, coco alkyldimethyl(3-sulfopropyl)

EC Number:

269-225-1

EC Name:

Betaines, coco alkyldimethyl(3-sulfopropyl)

Cas Number:

68201-55-8

Molecular formula:

C7H17NO3S·[CH2]6-16

IUPAC Name:

[3-(dodecyldimethylazaniumyl)propyl]trioxo-λ⁶-sulfanuide

Test material form:

other: not applicable for QSAR estimations

Details on test material:

Below there are the possible individual components ordered by the carbon number of the side chain with approximate contents listed:

C8: 0-12%, [O-]S(=O)(=O)CCC[N+](C)(C)CCCCCCCC
C10: 0-10%, [O-]S(=O)(=O)CCC[N+](C)(C)CCCCCCCCCC
C12: 45-57%, CCCCCCCCCCCC[N+](C)(C)CCCS(=O)(=O)[O-]
C14: 14-28%, CCCCCCCCCCCCCC[N+](C)(C)CCCS(=O)(=O)[O-]
C16: 5-13%, CCCCCCCCCCCCCCCC[N+](C)(C)CCCS(=O)(=O)[O-]
C18: 4-12%, [O-]S(=O)(=O)CCC[N+](C)(C)CCCCCCCCCCCCCCCCCC

Results and discussion

Vapour pressure

Vapour pressure 1

Key result

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: C12 (main) constituent

Remarks:

estimated by Modified Grain Method, using experimentally determined melting point

Vapour pressure 2

Key result

Temp.:

25 °C

Vapour pressure:

>= 0 - <= 0 Pa

Remarks on result:

other: range resulting from estimation for the C18 and C8 constituent

Remarks:

estimated by Modified Grain Method, using experimentally determined melting point

Applicant's summary and conclusion

Conclusions:

The study report describes a scientifically accepted calculation method for the vapour pressure using the US-EPA software MPBPWIN v1.43.No GLP criteria are applicable for the usage of this tool and the QSAR estimation is easily repeatable. The estimated vapour pressure values, derived from both estimated and determined melting points, range from 4.46E-12 Pa resp. 2.74E-12 Pa (C8) to 2.08E-16 Pa resp. 5.95E-16 Pa (C18), the vapour pressure of the C12 constituent lies with 8.59E-14 Pa resp. 9.69E-14 Pa in between. Taking into account the magnitude of the vapour pressure result it is considered that the result clearly indicates that Betaines, coco alkyldimethyl(3-sulfopropyl) is not volatile.

Executive summary:

The vapour pressure of the substance Betaines, coco alkyldimethyl(3-sulfopropyl) was determined by the computer program MPBPWIN v1.43 (EPIWIN software) by US-EPA (2012) by estimating the values for the single constituents. The program calculates the vapour pressure according to three different methods: Antoine, Modified Grain and Mackay. The Modified Grain method is preferentially adopted and therefore the most important one [Lyman, W.J., 1985. In: Environmental Exposure From Chemicals. Volume I., Neely, W.B. and Blau, G.E. (eds), Boca Raton, FL: CRC Press, Inc., Chapter 2]. The estimated vapour pressure values, derived from both estimated and determined melting points, range from 4.46E-12 Pa resp. 2.74E-12 Pa (C8) to 2.08E-16 Pa resp. 5.95E-16 Pa (C18), the vapour pressure of the C12 constituent lies with 8.59E-14 Pa resp. 9.69E-14 Pa in between. It is indicated that Betaines, coco alkyldimethyl(3-sulfopropyl) is not volatile.