Infrared absorption spectra of seven cyclopentanes and five cyclohexanes

The infra red a bsorp tion spectra of se ve n cyclop entane a nd fi ve cyclohexanes have been meas ured i n t he region from 2 to 15 microns. The s ubstances we re cyclop en tane, m e th y lcyclopen tane, 1, I-dimeth ylcyclopen tane, tmns-l ,2-di methylcyclopen tane, trans-I , 3-dimeth ylcyclopen tane, cis-l ,2-d im eth ylcyclopen tane, a nd cis, tmns, cis-l ,2,4-trimethy lcyclopen ta ne, also cyclohexa ne, meth ylcyclohexane, 1, I-dimeth ylcyclohexa ne, lmns-l ,2dimeth ylcyclohexane, and cis-l,2-dimethylcyclohexane. The wavelengths of all t he obse rv ed absorp ti on bands are g ive n i n a table, and a graph is shown of the per cen tage t ransmission over the wave length reg ion of each s ubstance. The h ydrocarbons were highl y purified in the C hemi t ry Division a nd these spectra will be of value as a check on the puri ty of t hese co mpounds which may be ob ta ined from other sources. Also t he m ore inte nse bands serve as a mea ns of ide nt ifi ca t ion. For each substance t he bands that are best s uited fo r distinguishing it a re noted .