CO-laser photoacoustic spectroscopy on dimerization of fatty acid, molecules

R. Kästle; M.W. Sigrist

doi:doi:10.1051/jp4:19947115

Issue		J. Phys. IV France Volume 04, Number C7, Juillet 1994 8th International Topical Meeting on Photoacoustic and Photothermal Phenomena 8 ITMP³ / 8éme conférence internationale de photoacoustique et photothermique


Page(s)		C7-491 - C7-494
DOI		https://doi.org/10.1051/jp4:19947115

8th International Topical Meeting on Photoacoustic and Photothermal Phenomena
8 ITMP³ / 8éme conférence internationale de photoacoustique et photothermique

J. Phys. IV France 04 (1994) C7-491-C7-494
DOI: 10.1051/jp4:19947115

CO-laser photoacoustic spectroscopy on dimerization of fatty acid, molecules

R. Kästle and M.W. Sigrist

ETH Zurich, Institute of Quantum Electronics, 8093 Zurich, Switzerland

Abstract
Absorption spectra of fatty-acid molecules with carbon number below five were recorded as a function of temperature and partial pressure in the 1560-1950 cm^-l wavelength range using photoacoustic spectroscopy with a CO laser as radiation source. A special Helmholtz PA cell providing good temperature uniformity and stability was developed and used to study flowing gaseous mixtures at varying temperatures. Dimerization enthalpies ΔH for acetic (ΔH=60.8 +/- 3.5 kJ/mole), propionic (ΔH=62.4+/-4.0kJ/mole), acrylic (ΔH=61.0+/-3.5kJ/mole) and butyric (ΔH=58.7+/-1.0kJ/mole) acid agree well with values obtained by other methods.