3-[(aminoiminomethyl)thio]propanesulphonic acid

Vapour pressure

Administrative data

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

supporting 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:

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
NC(=N)SCCCS(=O)(=O)O

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 result calculated for the organic substance 3-[(aminoiminomethyl)thio]propanesulphonic acid seems reasonable. No exact melting point has been determined experimentally, only a range; the start of melting (245.4 °C) and the experimentally determined boiling point (276.9°C) have been used for vapour pressure calculation. Further, due to the magnitude of the result it is considered as adequate.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to other study

Remarks:

Experimental 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.:

>= 245.4 - <= 249.3 °C

Decomposition:

no

Remarks on result:

other: mean melting range; no information on atm. pressure given

Conclusions:

The study was performed according to OECD TG102 without deviations and therefore reliability of Klimisch 2 has been assigned. The melting range of the test material has been determined to be 245.4 - 249.3 °C (mean value).

Executive summary:

The melting point / melting range of the test substance was determined in a non-GLP test according to OECD 102.

The test material 3-[(aminoiminomethyl)thio]propanesulphonic acid melts between 245.4 - 249.3 °C.

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Remarks:

Experimental boiling point

Reference

Endpoint:

boiling point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-03-13 - 2017-03-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling Point)

Version / remarks:

OECD 103, dated 27. Jul. 1995, “Boiling Point“

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

EU-Method A.2, dated 31. May 2008, “Boiling Temperature“

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Kaiser-Friedrich-Straße 7, 55116 Mainz, Germany

Type of method:

differential scanning calorimetry

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: The test item was stored in a tightly closed vessel at room temperature (15.8 – 22.0 °C) under dry conditions in the dark.

Key result

Boiling pt.:

276.6 °C

Atm. press.:

ca. 1 013.25 mBar

Decomposition:

no

Remarks on result:

other: mean of two experiments

Remarks:

SD ± 0.29°C

Conclusions:

The study was performed according to the OECD TG103 and EU Method A.2 (GLP) without deviations and therefore considered to be of the highest quality (reliability Klimisch 1). Differential scanning calorimetry is a scientifically reasonable method to determine not only the boiling point of a substance but also its melting point or decomposition temperature. There is no reason to believe that the results are not reliable. Two events were detected. As first event the melting point was determined with 257.28 ± 0.28 °C (530.43 ± 0.28 K), the second event is stated as the boiling point with 276.60 ± 0.29 °C (549.75 ± 0.29 K).

Executive summary:

The boiling point was determined via DSC (differential scanning calorimetry) according to OECD 103 resp. EU A.2 under GLP.

The boiling point was determined under these circumstances as the second event with 276.60 ± 0.29 °C (549.75 ± 0.29 K)

These values are the means of two independent determinations.

The first event was indicated as melting point with 257.28 ± 0.28 °C (530.43 ± 0.28 K)

Data source

Reference

Title:

EPI Suite Version 4.10

Year:

2012

Bibliographic source:

MPBPWIN - three separate methods for VP: Antoine method (1990), modified Grain method (1985) and Mackay method (1985)

Materials and methods

Test guideline

Guideline:

other: REACH guidance on QSARs Chapter R.6

Version / remarks:

May 2008

Principles of method if other than guideline:

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

Remarks:

(not applicable)

Type of method:

other: QSAR calculation

Test material

Test material information

Constituent 1

Reference substance name:

3-[(aminoiminomethyl)thio]propanesulphonic acid

EC Number:

244-520-8

EC Name:

3-[(aminoiminomethyl)thio]propanesulphonic acid

Cas Number:

21668-81-5

Molecular formula:

C4H10N2O3S2

IUPAC Name:

3-(carbamimidoylsulfanyl)propane-1-sulfonic acid

Specific details on test material used for the study:

SMILES: NC(=N)SCCCS(=O)(=O)O

Results and discussion

Vapour pressure

Vapour pressure 1

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: Modified Grain Method (MPBPWIN v1.43) - most relevant for solids

Vapour pressure 2

Temp.:

25 °C

Vapour pressure:

0.011 Pa

Remarks on result:

other: Mackay Method (MPBPWIN v1.43)

Vapour pressure 3

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: Antoine Method (MPBPWIN v1.43)

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 result is adequate for the regulatory purpose. The calculation resulted in a value of 0.000324 Pa (Modified Grain Method) at 25 °C.

Executive summary:

The vapour pressure of the substance 3-[(aminoiminomethyl)thio]propanesulphonic acid was determined by the computer program MPBPWIN v1.43 (EPIWIN software) by US-EPA (2012). 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].

A boiling point of 276.6 °C, a melting point of 245.4°C and an ambient temperature of 25 °C is assumed.

The Antoine Method gives a result of 0.000292 Pa, the Mackay Method results in a value of 0.0107 Pa and according to the Modified Grain Method the substance has a vapour pressure of 0.000324 Pa (most relevant for solids).

The estimation error increases as the vapour pressure decreases, especially when the vapour pressure is below 0.000133Pa, but the calculated value can anyway viewed as indicative of a very low vapour pressure, which is sufficient considering the magnitude of the result.