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Vapour pressure

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Endpoint:
vapour pressure
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Study period:
October 12, 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
The estimation methods here used are the following:
- Moller
- Nannoonal
- Myrdal and Yalkowsky
- EPA MPBPWIN (Antoine, modified Grain, Mackay)

EPA (MPBPWIN) Accuracy
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.

EPA (MPBPWIN) Estimation 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.

Other Evaluation methods
The estimation method reported in Nannoolal et al. (2004) provide the most accurate Tb values. Stein and Brown (1994) provided the second best estimation method for Tb. The prediction of vapour pressures for the 45 multifunctional compounds of Test set 2 showed that the method of Nannoolal et al. (2008) and the method of Moller et al. (2008) were better than the other vapour pressure methods studied when used with the Nannoolal et al. (2004) Tb estimation method.
Guideline:
other: ECHA Chapter R.06 - Guidance on QSARs and grouping of chemicals
Principles of method if other than guideline:
The accurate experimental measurement of low (1–103 Pa) and very low (<1 Pa) vapour pressures is a significant challenge. The use of modern pressure gauges means that it is theoretically possible to use the static method down to very low pressures but adsorption of volatiles (especially water) onto the surface of the apparatus and the presence of impurities in the sample make this method difficult to use in practice at low pressures.

(Q)SAR models were developed to overcome the difficulty of the experimental design.
Type of method:
other: in silico
Temp.:
25 °C
Vapour pressure:
4.5 Pa
Remarks on result:
other: Moller method
Temp.:
25 °C
Vapour pressure:
5.3 Pa
Remarks on result:
other: Nannoonal method
Temp.:
25 °C
Vapour pressure:
0.05 Pa
Remarks on result:
other: Myrdal and Yalkowsky method
Temp.:
25 °C
Vapour pressure:
1.39 Pa
Remarks on result:
other: EPA Modified Grain Method

DDBST SUMMARY

The vapour pressure (p0) of an organic compound is one of the main factors controlling its equilibrium partitioning between the gas and condensed (aerosol) phases.

Here we provide three structure-based estimators for vapour pressure, courtesy of DDBST GmbH: first, that Nannoolal et al. for boiling point coupled with the modified vapour pressure predictor of Moller et al.; second, the methods of Nannoolal et al. for both boiling point and vapour pressure; third, the method of Stein and Brown for boiling point coupled with the vapour pressure equation of Myrdal and Yalkowsky. Boiling points can alternatively be specified by the user.

The results include p0 of the liquid compound at 298.15 K, the enthalpy of vaporisation ΔH0(p0) and the associated heat capacity change ΔCp0(p0).

Results from the three methods are given below:

Moller Method

The normal boiling point predicted by the method of Rarey/Nannoolal is 509.797 K. Using this boiling point in the vapour pressure equation of Moller et al. yields the following results for the pure liquid compound at 298.15 K:

p0 = 4.4888E-05 atm,   ΔH0(p0) = 68.19 kJ mol-1

The value of po at the selected temperature of 298.15 K is 4.4888E-05 atm (4.5 Pa)

 

Nannoolal Method

The normal boiling point predicted by the method of Rarey/Nannoolal is 509.797 K. Using this boiling point in the vapour pressure equation of Nannoolal et al. yields the following results for the pure liquid compound at 298.15 K:

p0 =  5.2495E-05 atm,   ΔH0(p0)  = 65.55 kJ mol-1

The value of p0 at the selected temperature of 298.15 K is 5.2495E-05 atm (5.3 Pa)

 

Myrdal and Yalkowsky Method

The normal boiling point predicted by the method of Stein and Brown (4) is 612.300 K. Using this boiling point in the vapour pressure equation of Myrdal and Yalkowsky (5) yields the following results for the pure liquid compound at 298.15 K:

p0 =  4.4911E-07 atm,    ΔH0(po)  = 81.70 kJ mol-1    ΔCP0(p0)  = -91.05 J (K mol)-1

The value of po at the selected temperature of 298.15 K is 4.4911E-07 atm (0.05 Pa)

 

Notes

The above results were obtained using the Artist software package for thermodynamic property prediction. Artist includes many other methods, and also a UNIFAC calculator for activity coefficients in the liquid phase.

EPA SUMMARY MPBPWIN v1.43

Experimental Database Structure Match: no data

 

SMILES : CC1=CC2CC1C3C2C(=O)OC3(=O)

CHEM   : 5-METH

MOL FOR: C10 H10 O3

MOL WT : 178.19

---------------------- SUMMARY MPBPWIN v1.43 ----------------------

 

Boiling Point: 264.04 deg C (Adapted Stein and Brown Method)

 

Melting Point:  30.26 deg C (Adapted Joback Method)

Melting Point:  40.51 deg C (Gold and Ogle Method)

Mean Melt Pt:   35.38 deg C (Joback; Gold,Ogle Methods)

 Selected MP:   35.38 deg C (Mean Value)

 

Vapor Pressure Estimations (25 deg C):

 (Using BP: 264.04 deg C (estimated))

 (Using MP: 35.38 deg C (estimated))

 

   VP: 0.0102 mm Hg (Antoine Method)

       : 1.36 Pa (Antoine Method)

   VP: 0.0104 mm Hg (Modified Grain Method)

       : 1.39 Pa (Modified Grain Method)

   VP: 0.01836 mm Hg (Mackay Method)

       : 2.45 Pa (Mackay Method)

 

Selected VP: 0.0104 mm Hg (Modified Grain Method)

           : 1.39 Pa (Modified Grain Method)

      Subcooled liquid VP: 0.0129 mm Hg (25 deg C, Mod-Grain method)

                         : 1.72 Pa (25 deg C, Mod-Grain method)

 

 TYPE 

 NUM

 BOIL DESCRIPTION 

 COEFF  

 VALUE 

 Group

 1 

 -CH3             

  21.98 

  21.98

 Group

 1 

 -CH2- (ring)     

  26.44 

  26.44

 Group

 4 

 >CH- (ring)     

  21.66 

  86.64

 Group

 1 

 =CH- (ring)     

  28.03 

  28.03

 Group

 1 

 =C<  (ring)     

  28.19 

  28.19

 Group

 1 

 -COO- (ring)     

 172.49 

 172.49

  *

 Equation Constant

         

 198.18

RESULT-uncorr

 BOILING POINT in Kelvin 

 561.95

RESULT-corr

 BOILING POINT in Kelvin 

 537.20

 BOILING POINT in deg C      

 264.04

  

 TYPE 

 NUM

 MELT DESCRIPTION 

 COEFF  

 VALUE 

 Group

 1 

 -CH3             

  -5.10 

  -5.10

 Group

 1 

 -CH2- (ring)     

   7.75 

   7.75

 Group

 4 

 >CH- (ring)     

  19.88 

  79.52

 Group

 1 

 =CH- (ring)     

   8.13 

   8.13

 Group

 1 

 =C<  (ring)     

  37.02 

  37.02

 Group

 1 

 -COO- (ring)     

  53.60 

  53.60

  *

 Equation Constant

         

 122.50

  RESULT

 MELTING POINT in Kelvin 

 303.42

 MELTING POINT in deg C      

  30.26

Executive summary:

The majority of reliable vapour pressure estimations of 5-methyl-3a,4,7,7a-tetrahydro-4,7-methano-2-benzofuran-1,3-dione (5-METH), calculated using several methods, lead to results having the same order of magnitude and will be used to obtain a summary value suitable for the assessments of 1,2,3,6-tetrahydromethyl-3,6-methanophthalic anhydride (METH).

Endpoint:
vapour pressure
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Study period:
October 12, 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
The estimation methods here used are the following:
- Moller
- Nannoonal
- Myrdal and Yalkowsky
- EPA MPBPWIN (Antoine, modified Grain, Mackay)

EPA (MPBPWIN) Accuracy
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.

EPA (MPBPWIN) Estimation 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.

Other Evaluation methods
The estimation method reported in Nannoolal et al. (2004) provide the most accurate Tb values. Stein and Brown (1994) provided the second best estimation method for Tb. The prediction of vapour pressures for the 45 multifunctional compounds of Test set 2 showed that the method of Nannoolal et al. (2008) and the method of Moller et al. (2008) were better than the other vapour pressure methods studied when used with the Nannoolal et al. (2004) Tb estimation method.
Guideline:
other: ECHA Chapter R.06 - Guidance on QSARs and grouping of chemicals
Principles of method if other than guideline:
The accurate experimental measurement of low (1–103 Pa) and very low (<1 Pa) vapour pressures is a significant challenge. The use of modern pressure gauges means that it is theoretically possible to use the static method down to very low pressures but adsorption of volatiles (especially water) onto the surface of the apparatus and the presence of impurities in the sample make this method difficult to use in practice at low pressures.

(Q)SAR models were developed to overcome the difficulty of the experimental design.
Type of method:
other: in silico
Temp.:
25 °C
Vapour pressure:
6 Pa
Remarks on result:
other: Moller method
Temp.:
25 °C
Vapour pressure:
5.1 Pa
Remarks on result:
other: Nannoonal method
Temp.:
25 °C
Vapour pressure:
0.06 Pa
Remarks on result:
other: Myrdal and Yalkowsky method
Temp.:
25 °C
Vapour pressure:
1.89 Pa
Remarks on result:
other: EPA Modified Grain Method

DDBST SUMMARY

The vapour pressure (p0) of an organic compound is one of the main factors controlling its equilibrium partitioning between the gas and condensed (aerosol) phases.

Here we provide three structure-based estimators for vapour pressure, courtesy of DDBST GmbH: first, that Nannoolal et al. for boiling point coupled with the modified vapour pressure predictor of Moller et al.; second, the methods of Nannoolal et al. for both boiling point and vapour pressure; third, the method of Stein and Brown for boiling point coupled with the vapour pressure equation of Myrdal and Yalkowsky. Boiling points can alternatively be specified by the user.

The results include p0 of the liquid compound at 298.15 K, the enthalpy of vaporisation ΔH0(p0) and the associated heat capacity change ΔCp0(p0).

Results from the three methods are given below:

Moller Method

The normal boiling point predicted by the method of Rarey/Nannoolal is 510.351 K. Using this boiling point in the vapour pressure equation of Moller et al. yields the following results for the pure liquid compound at 298.15 K:

p0 = 5.9462E-05 atm,   ΔH0(p0) = 66.20 kJ mol-1

The value of po at the selected temperature of 298.15 K is 5.9462E-05 atm (6.0 Pa)

 

Nannoolal Method

The normal boiling point predicted by the method of Rarey/Nannoolal is 510.351 K. Using this boiling point in the vapour pressure equation of Nannoolal et al. yields the following results for the pure liquid compound at 298.15 K:

p0 =  5.0254E-05 atm,   ΔH0(p0)  = 65.76 kJ mol-1

The value of p0 at the selected temperature of 298.15 K is 5.0254E-05 atm (5.1 Pa)

 

Myrdal and Yalkowsky Method

The normal boiling point predicted by the method of Stein and Brown (4) is 606.076 K. Using this boiling point in the vapour pressure equation of Myrdal and Yalkowsky (5) yields the following results for the pure liquid compound at 298.15 K:

p0 =  6.2715E-07 atm,    ΔH0(po)  = 80.59 kJ mol-1    ΔCP0(p0)  = -91.05 J (K mol)-1

The value of po at the selected temperature of 298.15 K is 6.2715E-07 atm (0.06 Pa)

 

Notes

The above results were obtained using the Artist software package for thermodynamic property prediction. Artist includes many other methods, and also a UNIFAC calculator for activity coefficients in the liquid phase.

EPA SUMMARY MPBPWIN v1.43

Experimental Database Structure Match: no data

 

SMILES : CC12CC(C=C1)C3C2C(=O)OC3(=O)

CHEM   : 4-METH

MOL FOR: C10 H10 O3

MOL WT : 178.19

---------------------- SUMMARY MPBPWIN v1.43 ----------------------

 

Boiling Point: 256.55 deg C (Adapted Stein and Brown Method)

 

Melting Point:  41.64 deg C (Adapted Joback Method)

Melting Point:  36.13 deg C (Gold and Ogle Method)

Mean Melt Pt:   38.89 deg C (Joback; Gold,Ogle Methods)

 Selected MP:   38.89 deg C (Mean Value)

 

Vapor Pressure Estimations (25 deg C):

 (Using BP: 256.55 deg C (estimated))

 (Using MP: 38.89 deg C (estimated))

 

   VP: 0.0145 mm Hg (Antoine Method)

       : 1.93 Pa (Antoine Method)

   VP: 0.0142 mm Hg (Modified Grain Method)

       : 1.89 Pa (Modified Grain Method)

   VP: 0.0247 mm Hg (Mackay Method)

       : 3.29 Pa (Mackay Method)

 

Selected VP: 0.0142 mm Hg (Modified Grain Method)

           : 1.89 Pa (Modified Grain Method)

      Subcooled liquid VP: 0.019 mm Hg (25 deg C, Mod-Grain method)

                         : 2.53 Pa (25 deg C, Mod-Grain method)

 

 TYPE 

 NUM

 BOIL DESCRIPTION 

 COEFF  

 VALUE 

 Group

 1 

 -CH3             

  21.98 

  21.98

 Group

 1 

 -CH2- (ring)     

  26.44 

  26.44

 Group

 3 

 >CH- (ring)     

  21.66 

  64.98

 Group

 2 

 =CH- (ring)     

  28.03 

  56.06

 Group

 1 

 >C<  (ring)     

  11.12 

  11.12

 Group

 1 

 -COO- (ring)     

 172.49 

 172.49

  *

 Equation Constant

         

 198.18

RESULT-uncorr

 BOILING POINT in Kelvin 

 551.25

RESULT-corr

 BOILING POINT in Kelvin 

 529.71

 BOILING POINT in deg C      

 256.55

  

 TYPE 

 NUM

 MELT DESCRIPTION 

 COEFF  

 VALUE 

 Group

 1 

 -CH3             

  -5.10 

  -5.10

 Group

 1 

 -CH2- (ring)     

   7.75 

   7.75

 Group

 3 

 >CH- (ring)     

  19.88 

  59.64

 Group

 2 

 =CH- (ring)     

   8.13 

  16.26

 Group

 1 

 >C<  (ring)     

  60.15 

  60.15

 Group

 1 

 -COO- (ring)     

  53.60 

  53.60

  *

 Equation Constant

         

 122.50

  RESULT

 MELTING POINT in Kelvin 

 314.80

 MELTING POINT in deg C      

  41.64

Executive summary:

The majority of reliable vapour pressure estimations of 4-methyl-3a,4,7,7a-tetrahydro-4,7-methano-2-benzofuran-1,3-dione (4-METH), calculated using several methods, lead to results having the same order of magnitude and will be used to obtain a summary value suitable for the assessments of 1,2,3,6-tetrahydromethyl-3,6-methanophthalic anhydride (METH).

Description of key information

Vapour pressure (METH): 5.2 Pa at 25 °C
Vapour pressure (METHAc): 2.4E-5 Pa at 25 °C

Key value for chemical safety assessment

Vapour pressure:
5.2 Pa
at the temperature of:
25 °C

Additional information

The vapour pressure was assessed both on the anhydride and the corresponding acids, applying estimation methods by (Q)SAR techniques to its well defined isomers. Such methods have been used as the expected vapour pressures were at the lower limit of what can be determined experimentally in a reliable way.

For the anhydride form, being the Moller and Nannoolal methods better than the other vapour pressure methods studied when used with the Nannoolal et al. Tb estimation method, it appears reasonable to calculate the mean of them, to obtain a summary value suitable for the assessments:

VPMETH = (4.5 +6.0 +5.3 +5.1) / 4 = 5.2 Pa at 25 deg C

In case of acid forms (two carboxylic groups), the Moller method appears as the most reliable for the assessments.

VPMETHAc= (1.7E-5 + 3.0E-5) / 2 = 2.4E-5 Pa at 25 deg C

Measured vapour pressures of the anhydride, at different temperatures, were extrapolated to estimate the vapour pressure at 25 °C, giving a limit value of < 14 mbar (<1400 Pa).