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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
phototransformation in air
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well designed, peer-reviewed study but not conducted by GLP or according to a guideline method.

Data source

Reference
Reference Type:
publication
Title:
Photoisomerization and Photodissociation of Aniline and 4-Methylpyridine
Author:
Tseng, CM, Dyakov YA, Huang CL, Mebel AM, Lin SH, Lee YT and Ni CK.
Year:
2004
Bibliographic source:
J Am Chem Soc. 126, 8760-8768

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
4-Methylpyridine vapour in high pressure helium was photodissociated by a 193 nm laser pulse and then ionized by a VUV laser pulse. A pulsed electric field was used to extract the ions into a mass spectrometer equipped with a two-dimensional detector used to detect the ion positions and intensity distribution.
GLP compliance:
not specified

Test material

Constituent 1
Reference substance name:
4-methylpyridine
EC Number:
203-626-4
EC Name:
4-methylpyridine
Cas Number:
108-89-4
IUPAC Name:
4-methylpyridine
Details on test material:
as provided in earlier publications of the author.

Study design

Light source:
other: VUV LASER
Light spectrum: wavelength in nm:
118.2
Reference substance:
yes
Remarks:
aniline; also toluene

Results and discussion

Quantum yield (for direct photolysis):
1
Results with reference substance:
A dissociation rate of 4.5 x 10^6s-1was obtained for aniline.

Any other information on results incl. tables

A dissociation rate of 1.4 x 106s-1was obtained for 4 -methylpyridine. About 10% of 4 -mehtylpyridine was phototransformed.

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Remarks:
not a guideline study
Conclusions:
Photolysis of 4-methylpyridine (maximum 10%) occurs after absorption of light of 118 nm wavelength (very low ultraviolet), resulting in a loss of the methyl group or loss of a methyl hydrogen.
Three members of the pyridine and methyl pyridine derivatives category are listed in Regulation (EC) No. 1272/2008, Annex VI: Pyridine (Index #613-002-00-7, 2-methylpyridine (Index # 613-036-00-2) and 4-methylpyridine (Index # 613-037-00-8). The classifications are similar within the category, with the methyl derivatives classified as more corrosive than pyridine. The application of a chemical category is adequate for classification and labelling.