I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
March 1947
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iCKNOWLEDGME3T
TABLE VI. COXPARISOX OF PROCESSES INVESTIGATED I Kone
Process No. Catalyst used Optimum pressure, lb./sq. in. Optimum temp., C . Optimum mole ratio, HF:CCln Optimum space velocity per hr. Analysis of product, So CCl*F? CCLF CC1; Yield of C C h F i CC12F2from CClr, % Utilization of H F per pass, 70 Production of CClzF2, Ib./cu. f t . reactor/hr.
1000
I1
Activated C
460 2 600
1000 425 2 800
30 60
50
10 85 50
15
I11
+
FeCh activated C 100 300 1, 8. 5000
50 0 95
TO
75 20 5 95 90
44
440
tion, the rate of production over a longer period would be soniewhat l o m r , depending upon the fraction of the total time spent in regeneration. The recycling of triclilorofluorornethane has been shon-n to be feaqible in process 111. This variation of the process requires essentially no change in conditions, causes no appreciable change in yield or utilizotion of hydrogen fluoride, and causes a slight increase in the rate of production of dichlorodifluoromethane.
The authors wish to express ,their appreciation t o the Virginia Smelting Company, whose financial assist,ance made this research possible. LITERATURE CITED
(1) Daudt, 13. I\-.,and Youkeu, M.A., Brit. Patent 128,445 (;\lay 7, 1935); U.9. Patent 2,005,706 (June 18, 1935). (2) Daudt, H. IT., and Youker, 31. A,, U. 8. Patents 2,005,706 and 2,005,709 (June 18, 1936). (3) I b i d . , 2,005,707 (June 18, 1935). (1)I b i d . , 2,006,710 (June 18, 1935). ( 5 ) Daudt, H. IT,, Youker, h1.A,. and Reynolds, H. H., I b i d . , 2,024,095 (Dee. 10, 1935). (G) Goodhue, L. D., IND. ENG.CHEM.,34, 1456-9 (1942); Sullivan, IT. S . .Goodhue. L. D.. and Fales, J. H., J . Econ. Entond., 35, 48 (19i2). (7) Kinetic Chemicals Corp., French Patent 43,972 (addition to 720,171) (Sept. 26, 1934); Leicester, F. D., Brit. Patent 408,447 (Jan. 4, 1936); U. S. Patent 2,110,369 (March 8, 1938). (8) Ryan, H. W.B., Chern. -\'em, 143,331-3 (1931): Thompson, It. J . , ISD.E S G . CHBJI., 24, 620-3 (1932). P R E Y E X T Ebefore D the bIeeting-in-Miniature a t Purdue University, Kov. 17. 1945. This paper contains material abstracted from the doctoral theses of L. IT-. Frost and Z. D. Welch, submitted t o the faculty of Purdue University.
FLUORINATED DERIVATIVES OF ETHANE E. T. McBee. H. B. Hass, W. A. Bittenbender', W. E. Weesner*, T. G. Toland, Jr.$, W. R . Hausch4. and L. W. FrostS PURDUE U S I V E R S I T Y AVD PURDUE RESEARCH FOUNDATION, LAFAYETTE, IND.
TIUCHLOKOETHTLENE has been coiiterted to 2chloro-l,l,l-trifluoroetharie and 1,2-dichloro-l,l-difluoroethane with hqdrogen fluoride. These compounds haie also been produced bj a new thermal chlorination procedure from CFJCH2 and CCIF,CH,, respectitelj. The latter method jielded a new compound, CFaCHC12. Two improted processes for preparing CF3CHs with hj drogen fluoride have been de\ised (a)from CCI,CHa, and ( b ) from CCl,=CHz; yields of oier 9870 hare been obtained. Seieral other efficient processes for the preparation of fluorinecontaining ethanes are given.
T""
investigation was initiated for the purpose of making certain fluorine-containing derivatives of ethane available for pharmacological evaluation (9, I O ) . The research vias continued over a lengthy period, and a t least one publication describing the pharmacology of some of these compounds has already appeared ( 1 2 ) . I n preparing the fluorinated ethanes, an important consideration in each case was the availability of an efficient process. Certain known processes were found t o be unsatisfactory and, for some compounds, a neiv approach as necessary. Considerable effort was devoted to origination and development of methods for the production of these compounds, and certain results are noly reported for several of the fluorinated ethanes concerned. Trifluoroethane, observed by Snarts as a by-product of the hydrogenation of trifluoroacetic anhydride (l4),has been obtained by the reaction of CCl,CH, and a 9 to 1 mixture of antinioriy trifluoride and antimony dichlorotrifluoride (6). The 1 2
3 4 6
Pa.
Present Present Present Present Prebent
address, 1\Ierck 8: Company, Rahway, S . J . address, Monsanto Chemical Company, St. Louis, 1\10, address, California Research Corporation, Richmond, CJlif. address, Baker Chemical Company, Phillipsburg, N . J . address, Kesringhouse Electric Corporation, East Pittsburgh,
compound has likewise been prepared by heating CClaCH, and anhydrous hydrogen fluoride in a closed system a t 150" C. ( 8 ) . It has been established that much higher yields of CFJCH3are obtained by reacting CCl,CH, with hydrogen fluoride at about 225' C. under autogenous reaction pressures as high as 5000-6000 pounds per square inch. The superatmospheric pressure reactions were carried out in a manner similar to that described iu another paper ( 1 0 ) . Best results were obtained with about twice the amount of hydrogen fluoride theoretically required for replacement of all chlorine atoms by fluorine atoms. When only the amount of hydrogen fluoride theoretically necessary for conversion to CF3CHPwas used, the product consisted of C C ~ F ~ C H J and CCl,FCH,. The mode of operation involved heating the reaction mixture in an autoclave at about 225' C. for 16-20 hours, alloviin? the autoclave to cool for about 30 minutes, and then discharging the products. Conversions to CFsCHs of the order of SO% were obtained in this manner (Table I). Another commercially applicable method for the preparation of CFsCHa was developed during the present work; CCly-=CH, is treated with hydrogen fluoride under essentially the same optimum conditions as those employed for converting CCllCHs to C F ~ C Hn-itli J hydrogen fluoride; an additional stipulation is that an inhibitor is required to prevent polyiuei.ization of CCl,=CH,. Diphenylamine proved satisfactory in tlii. c:ipacity for the experiments reported in Table 11. \-ield- of fluorinated product attain 90%, and conversions to CFaCH, are as high as 74%. The ratio of CF3CH3t o CClF,CH, in thr pmtiuct increased with an increase in reaction time and ni:L\- also Iw varied by :Lltering tlie ratio of reactants. S o CCl?FCH., ~ : i b isolated from the products n-lien operating n-ithiii the mnge of conditions rclmrted in Table 11. 2-Chloro-l,l,l-trifluoroetliane has been ideiitified os 2 product from the reaction of CHF,CHCl, v i t h antinioii~-trifluoride and antimony dichlorotrifluoride under pressure (5.1 ; CClF2CHzC1 has been prepared from CC1.1C112C1by treatnient lyitli antimony
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 39, No. 3
it, concentration in the reaction zone was therefore small. Otherwise, under thr. Expt Su 38 38 G 49 E 49 I) 49 .J 49 I 49 R 49 N conditions employed, the dehydrochlorinaTemp., C. 100 150 200 200 '10 225 230 230 tion of CClF,CHCI? appears to occur more Pressure, I b . / i q . i l l . 200 1800 5200 5200 3400 5500 5400 5500 Time hours 4 20 5 1 6 . :i 7 8 rapidly than that of CC1F,CH2C1. As itt 10 16.5 C C I ~ ~ moles H~, 1 5 2.5 5 5 5 5 5 the chlorination of CF,CH:spite of reduction in time and mol^ ratio of chlorine t o organic material, trifluoride and antimony pentachloride (3). h t l l ~
