Ammonium 3-nitrobenzoate

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:

According to REACH Annex VII column 2, if the melting point is between 200°C and 300°C, a limit value based on measurement or a recognised calculation method is sufficient. In the most recent melting point determination on the purified / dried substance, the test material started to melt at 202°C, decomposition started at 206°C.

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
N(=O)(=O)c1cc(C(=O)ON(H)(H)(H))ccc1

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 Ammonium-3-nitrobenzoate seems reasonable. No exact melting point has been determined experimentally, only a range; the test material started to melt at 202°C, decomposition started at 206°C. So, the estimated melting and boiling points have been used for vapour pressure calculation. Further, due to the magnitude of the result it is considered as adequate.

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

Specific details on test material used for the study:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: dried in a desiccator over night

Key result

Melting / freezing pt.:

>= 202 °C

Decomposition:

yes

Decomp. temp.:

>= 206 °C

Sublimation:

no

Conclusions:

The melting point was aimed to be determined in a scientifically well-conducted study according to OECD TG 102, the results are hence sufficiently reliable. Melting started at 202°C, decomposition started at 206°C, most probably due to ammonia elimination based on the test item's molecular structure.

Executive summary:

The melting point of the test material ammonium-3-nitrobenzoatewas determined experimentally using the capillary method in a non-GLP test according to OECD guideline 102. The test material started to melt at 202°C, decomposition started at 206°C.

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:

2012

Bibliographic source:

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

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:

The computer program MPBPWIN (v1.43) by US-EPA is used for this estimation. It is based on the Antoine, Modified Grain and Mackay method. The Modified Grain method is preferentially adopted.

GLP compliance:

no

Remarks:

(not applicable)

Type of method:

other: QSAR calculation

Test material

Test material information

Constituent 1

Reference substance name:

Ammonium 3-nitrobenzoate

EC Number:

242-965-2

EC Name:

Ammonium 3-nitrobenzoate

Cas Number:

19328-56-4

Molecular formula:

C7H5NO4.H3N

IUPAC Name:

ammonium 3-nitrobenzoate

Test material form:

not specified

Details on test material:

SMILES : N(=O)(=O)c1cc(C(=O)ON(H)(H)(H))ccc1

Results and discussion

Vapour pressure

Vapour pressure 1

Key result

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

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

Vapour pressure 2

Temp.:

25 °C

Vapour pressure:

0 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.

Executive summary:

The vapour pressure of the substance ammonium-3-nitrobenzoate 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 443.92 °C and an ambient temperature of 25 °C is assumed. The Antoine Method gives a result of 0.000000154 Pa (1.54E-007 Pa), the Mackay Method results in a value of 0.00000491 Pa (4.91E-006 Pa) and according to the Modified Grain Method the substance has a vapour pressure of 0.00000191 Pa (1.91E-006 Pa) .