Infrared absorption spectra of seven cyclopentanes and five cyclohexanes

Abstract

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 ,2-dimeth 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 .Of special in te res t are the four dimethylcyclopen ta nes whi ch we re studi ed. The stru ct ural p osit io ns of t he s ubstit u ted meth yl groups differ only sligh tly, bu t the spectral d iffe rence is q ui te mar ke d. The infra red a hso rp tion spectra a re we ll s ui ted to show characteristic differences between isomers.The meas uremen ts were ma de w ith a Perkin -Elmer spectro mete r wi th a Ge ne ral M otor amplifier and Brown recorder. A sli t co ntrol mecha nis m is describe d in d etail. Although t he slit control gear arrangem ent is relatively simpl e, the results obtained wi th i t aloe good, The e nergy outpu t is held nearl y co nstant from 3. 5 to 14.5 m icrons .

Vibrational spectra of tetrafluoroethylene and tetrachloroethylene

“…The general m ethod of m easurement has been describ ed previously [3,4]. To ensure adequate resolution over the range 3 to about 52 J1.…”

“…The first two were used in P erkin-Elmer model 21 and J?aird Associates instruments, r espectively, and the 1 Presen ted before the American Physical Society at its meetin g in Washington, D. C., on M ay 1,1953. , Thi s work has been supported in part by the O"R under contract N Aonr 112-51. 3 D ereafter in this paper tetraflu orethylene, F ,C: CF" will be abbreviated to TF ]" and tetracbloroethylene, C]'C:CC]', will he contracted to TCE.…”

“…3 D espite a considerable body of earlier work, several fundamentals in each molecule have remained in doubt or unobserved . The availabili ty of a cesium iodide prism [1] 4 has made conveni ent the extension of the observable spectral range to about 52 1-', with the result for TFE and TCE that several hitherto unsuspected and otherwise unattainable band s have been r evealed.…”

Flame spectrum of acetylene from 1 to 5 microns

“…The only modification of the spectrometer was the removal of the cover of the source box and rotation of the plane mirror to permit location of the flame source at a convenient point without removing or disturbing the globar source unit. A continuous record of the spectrum was obtained by employing the amplifying and recording equipment described in an earlier publication [3]. An industrial oxyacetylene welding outfit, kindly placed at our disposal by this Bureau's welding shop, was used to provide the flame source.…”

Infrared spectra of bromochloromethane, dibromomethane, tribromochloromethane, and tetrabromomethane

“…In the thallium bromide-iodide region between 24 and 36 f.L it was necessary to use cell thicknesses of 1.5 mm to bring out the weaker absorp tion bands. The method of measurement and the reducing of data have been de crib ed in a previous paper [1 ].I Bromochloromethane, dibromomethane, and tribromo chloromethane were obtained from the Dow Chemical Company and tetrabromomethane from the Eastman Kodak Company.…”