Terphenyl

Vapour pressure

Administrative data

Endpoint:

vapour pressure

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Study period:

1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepta ble, well-documented report which meets basic scientific principles

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

according to Mackay D., A. Bobra, D.W. Chan and W.Y. Shiu. Vapor pressure Correlations for Low-Volatility Environmental Chemicals. Environ. Sci. Technol., 16, 645 (1982)

GLP compliance:

no

Remarks:

not relevant

Type of method:

other: calculation of vapour pressure

Test material

Test material information

Constituent 1

Reference substance name:

o-terphenyl

EC Number:

201-517-6

EC Name:

o-terphenyl

Cas Number:

84-15-1

Molecular formula:

C18H14

IUPAC Name:

1,1':2',1''-terphenyl

Constituent 2

Reference substance name:

m-terphenyl

EC Number:

202-122-1

EC Name:

m-terphenyl

Cas Number:

92-06-8

Molecular formula:

C18H14

IUPAC Name:

1,1':3',1''-terphenyl

Constituent 3

Reference substance name:

p-terphenyl

EC Number:

202-205-2

EC Name:

p-terphenyl

Cas Number:

92-94-4

Molecular formula:

C18H14

IUPAC Name:

1,1':4',1''-terphenyl

Details on test material:

no test material was used

Results and discussion

Vapour pressure

Vapour pressure 1

Temp.:

ca. 25 °C

Vapour pressure:

ca. 0 atm

Remarks on result:

other: o-terphenyl (calculated value)

Vapour pressure 2

Temp.:

ca. 25 °C

Vapour pressure:

ca. 0 atm

Remarks on result:

other: m-terphenyl (calculated value)

Vapour pressure 3

Temp.:

ca. 25 °C

Vapour pressure:

ca. 0 atm

Remarks on result:

other: p-terphenyl (calculated value)

Transition / decomposition

Transition / decomposition:

no

Any other information on results incl. tables

Vapor pressures calculated according to the method of Mackay* are presented in Table 1. The vapour pressures of terphenyls are between those of biphenyl and quaterphenyl.

The parameters used in the calcuation equation are the boiling point and the melting point.

Table 1: Calculated vapor pressure at 25°C
Compound	Boiling point (°K)	Melting point (°K)	Calculated vapor pressure at 25°C (atm)
Biphenyl	528.9	343	1.6 x 10^-5
o-Terphenyl	605	330	4.3 x 10^-7
m-Terphenyl	638	360	3.7 x 10^-8
p-Terphenyl	656	482.5	8.0 x 10^-10
m,m-Quaterphenyl	744	359	1.0 x 10^-10
p,p-Quaterphenyl	793	591	3.0 x 10^-14

* Mackay D., A. Bobra, D.W. Chan and W.Y. Shiu. Vapor pressure Correlations for Low-Volatility Environmental Chemicals. Environ. Sci. Technol., 16, 645 (1982)

Applicant's summary and conclusion

Conclusions:

Vapor pressures were calculated according to the method of Mackay (1982). The method which is applicable for hydrocarbons that boil above 100°C is considered valid for the terphenyls. It was validated with 72 different compounds with known vapor pressures. The mean error was 1.25.
The estimated vapor pressures of o-, m- and p- terphenyls are in line with the vapor pressure of other polyphenyls. The vapour pressure decreases with each additional ring, leading to a vapour pressure for the terphenyls that is between the vapour pressure of the bi- and quaterphenyls.

Executive summary:

Vapor pressures of some polyphenyls were estimated from known physical properties i.e. melting point and boiling point. Vapor pressure ranged from 1.6x10^-5to 3.0x10^-14atmosphere. The vapor pressure decreased dramatically as the number of rings increased – approximately 2 to 3 orders of magnitude for each additional ring. The estimated vapor pressure of the o-, m- and p-terphenyls ranged from 4.3 x 10^-7to 8.0 x 10^-10atmosphere.