2-methylbutane

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

up to 2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Source is a published handbook, no data on GLP/guideline compliance/method. Acceptable with restriction as handbook is peer reviewed and considered a reliable source

Principles of method if other than guideline:

The use of secondary sources of data is acceptable when they are based on a critical evaluation of peer-reviewed data and a consequent selection of a reliable and representative value for the property under investigation. The introduction to the CRC Handbook of Chemistry and Physics states that data for physical constants have been taken from many sources, including both compilations and the primary literature. Where conflicts were found, the value deemed most reliable was chosen. Therefore, although the method used is not known, the values presented here are acceptable as they are from a reliable secondary source of phys chem. data.

GLP compliance:

not specified

Remarks:

not reported

Type of method:

other: Not reported

Key result

Temp.:

27.5 °C

Vapour pressure:

100 kPa

Conclusions:

The vapour pressure of 2-methylbutane (isopentane) is 100kPa at 27.5 °C. Mackay (2000) reports vapour pressures ranging from 82.7 kPa at approximately 22 °C to 99.5 kPa at 25 °C. However most of these values were estimated using a variety of equations reported in the literature.

Executive summary:

There is no available information on the methods used to determine the value for this endpoint. However, this information is taken from the CRC Handbook which is considered to be a reliable peer reviewed handbook and suitable for use as the key study for this endpoint. There is also corrobarating evidence from other sources which support the selection of this value as the key study. Therefore 2-methylbutane has a vapour pressure of 100kPa at 27.5 °C.

Description of key information

The vapour pressure is between 74 and 79 kPa at 20°C for 2-methylbutane based on calculated values.

Key value for chemical safety assessment

Vapour pressure:

79 kPa

at the temperature of:

20 °C

Additional information

The vapour pressure is between 74 and 79 kPa at 20°C for 2-methylbutane based on calculated values. This range has been agreed by the consortium to represent the substance. This is supported by a value of 100 kPa at 27.5°C from the CRC Handbook (Lide 2008). There is no information available on the methods used to determine the value for this endpoint. However, the CRC Handbook is considered to be a reliable, peer-reviewed handbook and suitable for use as a study for this endpoint.