GAS CHROMATOGRAPHIC SEPARATION OF CARBONYL FLUORIDE AND CARBON DIOXIDE by George A. Drennan and Richard A. Matula Fluid Dynamics Laboratory Department of Mechanical Engineering College of Engineering The University of Michigan Ann Arbor, Michigan This research has been sponsored by the Air Force Office of Scientific Research, Office of Aerospace Research, United States Air Force, under Grant AF-AFOSR-1144-66, and administered through the Office of Research Administration, The University of Michigano Reproduction in whole or in part is permitted for any purpose of the United States Government.

GAS CHROMATOGRAPHIC SEPARATION OF CARBONYL FLUORIDE AND CARBON DIOXIDE George A. Drennan Richard A. Matula ABSTRACT An experimental method for the quantitative analysis of both CO2 and CF20 in gas mixtures is described. The analysis is based on thermal conductivity gas chromatography techniques, and it is shown that the detector response is linear over a wide range of CF20 concentrations.

-2 - INTRODUCTION The simultaneous quantitative evaluation of CF2O-CO2 mixtures is important in numerous kinetic studies including the oxidation of C2F4 and the pyrolysis of CF20. The gas chromatographic analysis of CF20 has been reported by Cordes (1) and Banks, Haszeldine and Sutcliffe (2). Unfortunately neither of these columns can separate CF2O-C02 mixtures. Heicklen and co-workers (3-4) have measured CF20 in gas mixtures by quantitatively converting the CF20 to CO2 on silica gel columns and measuring the CO2 effluent. The purpose of this paper is to describe a gas chromatographic technique for the simultaneous quantitative determination of both CF20 and CO2. EXPERIMENTAL Apparatus. An Aerograph model No. 202-B gas chromatograph equipped with a thermal conductivity cell was used for this study. Mixtures were introduced into the gas chromatograph through a gas sampling valve used in conjunction with a 2 ml sample volume. Peak areas were measured with a Disc Integrator (5000 counts/min) which was attached to a Sargent 10 in. recorder.

-3 - Column Materials and Preparation. A 6-foot composite column consisting of 2-feet of 50/80 mesh Porapak (Waters Associate, Inc.) type T followed by 4-feet of 50/80 mesh Porapak type N was used for the analysis. The column was packed in 1/4 inch O.D. Type 316 stainless steel tubing. Before final installation in the chromatograph, the column was heated to 2000 C and purged with helium (60 ml/min) for 2 hours. Prior to each series of runs the column was conditioned by passing three 250 mm of Hg samples of CF20 through it. RESULTS AND DISCUSSION A typical chromatogram indicating the spearation of CF20 and CO2 as obtained with the column described above is given in Figure 1. The operating conditions corresponding to the results given in Figure 1 are; column temperature 230 C; helium flow rate 60 ml/min. A plot of CF20 peak area as a function of CF20 pressure in the 2 ml sample volume is shown in Figure 2. These results indicate that the detector response is linear over an eleven fold increase in CF20 concentration. The curve given in Figure 2 approaches the origin as the sample pressure is decreased. This behavior indicated that CF20 absorption on this column is essentially nonexistent.

ACKNOWLEDGEMENT This research was sponsored by the Air Force Office of Scientific Research, Office of Aerospace Research, United States Air Force, under Grant number AF-AFOSR-1144-66.

-5 - REFERENCES 1. KL. Cordes, "Ozone-initiated Oxidation of Tetrafluoroethylene", Chemistry and Industry, 340, (Feb. 19, 1966). 2. R.E. Banks, R.N. Haszeldine and H. Sutcliffe, "Polyfluoroalky Derivatives of Nitrogen. Part XI. The Photolytic Decomposition of Some Perfluoro-l,2-Oxazetidines," J. Chem. Soc. (Lon.) 4066, (Sept.-Oct. 1964). 3. J. Heicklen, V. Knight and S. Green, "Mercury Photosensitized Oxidation of Tetrafluoroethylene," J. Chem. Phy., 42, No. 1, 221, (1965). 4. Dennis Saunders and Julian Heicklen, "The Reaction of Oxygen Atoms with Tetraflucroethylene, " J. Am. Chem. Soc., 87, No. 10, 2088 (1965).

w U) z 0 aU) w w 0 0 w cr 0 CF20 Co2 I I I I I I I -L I15 a a 3 6 9 12 15 TIME, MIN FIG.I TYPICAL CHROMATOGRAM OF C%- CFO MIXTURE

6 5, U3 0 go rO 0) 0 x D.. 0 0_ 4 3 2 0 I I I I I I 100 200 300 400, mm of Hg 500 600 PCF2O FIG.2 CFO 2 PEAK AREA AS A FUNCTION SAMPLE PRESSURE OF

Unclassified Security Classification DOCUMENT CONTROL DATA- R & D (Security classification of title, body of abstract and indexing nnotation must be entered when the overall report is cl fi~ed) I. ORIGINATING ACTIVITY (Corporate author) 24. REPORT SECURITY CLASSIFICATION Unclassified The University of Michigan "b. CROUP Department of Mechanical Engineering 3. REPORT TITLE GAS CHROMATOGRAPHIC SEPARATION OF CARBONYL FLUORINE AND CARBON DIOXIDE 4. DESCRIPTIVE NOTES (Type of report and inclusive dates) 5. AU THOR(S) (First name, middle initial, last name) George A. Drennan and Richard A. Matula 6. REPORT DATE 7a. TOTAL NO. OF PAGES 7b. NO. OF REFS December, 1967 7 4 Oa. CONTRACT OR GRANT NO. f9a. ORIGINATOR'S REPORT NUMBER(S) AF-AFOSR-1144-66 Fluid Dynamics Laboratory b. PROJECT NO. | Publication No. 67-2 c.~ 61445A014 AK|A9h. OTHER REPORT NO(S) (Any other numbers that may be assigned this report) d. 681308 10. DISTRIBUTION STATEMENT II. SUPPLEMENTARY iNOTES 12. SPONSORING MILITARY ACTIVITY Air Force Office of Scientific Tech, other Research (SREP) 1400 Wilson Boulevard 13. ABSTRACT - An experimental method for the quantitative analysis of both CO2 and CF20 in gas mixtures is described. The analysis is based on thermal conductivity gas chromatography techniques, and it is shown that the detector response is linear over a wide range of CF2O concentrations. I I DD I NO1473 Trnc lascsi f i ed Securitv Classification

Unclassified v d,, s_;,M +c u -j8Zti,ecurtiv A.assiticatiuo 14,LIN K A LINK 8 LINK1 C KEY WORDS - ROLE WT ROLE WT OLE W T _ --- —-...... I Qarbonyl Fluoride Carbon Dioxide Gas Chromatography f.4 I I I -- - - a a - - I - Unclassified Sec u lrlt (' I i'-; i fi ('i t 1,rn