INDUSTRIAL AND ENGINEERING CHEMISTRY
March 1947
pressures. A longer time is usually required than with chlorinated methylbenzenes, as fluorination catalysts, such as antimony pentachloride, seem to have no efEect on flnorination rate. T h e chlorinated methylpyridines are apparently not fluorinated with antimony trifluoride a t ntniospheric pressure.
391
with 9 5 5 ethyl alcohol. Table I gives the chemical analysis and properties of the compounds. ACKNOW LEDGhlENT
Acknowledgment is made of the finnncial assistant of the U. S. S a v n l Research Laboratories which made this work possible.
PROPERTIES O F COMPOUNDS LITERATURE CITED
hlthough these componnds are derivatives of pyridine, they have no basic properties. S o hydrochloride precipitates when hydrogen chloride is bubbled through a benzene solution of t h e chlorinated or fluorinated niethylpyridine. These compounds are not hydrochlorides or hydrofluorides, as shon-n by their insoluhilitr in Xvnter acid solubility in organic liouids such as ether, benzene, 2nd petroleum ether. 2,(j_Bis(trifl,1oron1ethyl)pyridine properties, ii a solid fluoro Tvithinteresting being solnble in alcohols na well as ethers and hydrocarbons. C~iloro-2,6-bi~~(trifluoromethyi)pyridine is completely miscible
(1) Ost, H., J . p r a k t . C'hem., 121 27, 257-94 (1883). (2) Purvis, J. E.. and Foster, IT, H., Proc. Comb. Phil. Soc., 14,381-4 (1907). (3) Sell, W.J., J . Chem. Soc., 1905, 799-804; 1908, 1993-6. (4) Sell, IT, J., and Dootson, F. TT., I b i d . , 1897,1068. (5) Seyffertli, J . p r a k t . Chem., [ 2 ] 34,241-63 (1586).
Y
PRESESTED before the Ry~rlposiunlo n Fluorine Clreiiri~tryas parr. of paper i 8 , Division of Industrial and Engirleeriirg Chenlistry, 110th 1Ieeting of .L\IERIC.AS C H E \ I I C .SOCIETY, ~L Chicago, Ill. Based o n a thesis presented t o the f a c u l t y of Purdue t-niversity by E,A I , H o d n e t t i n partial fulfillm e n t of requirenrents for the degree of doctor of philosophy.
(FLUORINATED HETEROCYCLIC COMPOUNDS)
(PerhaLoaLkyl)triazines E. T. JIcBee, 0. R . Pierce, and R . 0. Bolt' P U R D U E U 4 I V E R S I T 1 . i \ D P U R D U E R E S E i R C H FOL\DATIOV, L I F i E ETTE, IYD.
2,1,6-TRIS( tricliloronieth~I)-1,3,~-triazi1ie +I as prepared h? pol? nierizinp trichloroacetonitrile M ith anh?drous h>drogeii chloride at a pressure of 800 pounds per square inch. Trichloroacetoiiitrile $+a5produced frcni trichloroacetamide niade by animonol?sis of eth,l tricliloroacetate. 2, L.,6-Tris(tric.hloro1iietli~1)-1,3,.i-triaziiie w as fluorinated with h>dropeii fluoride and antimoil? pentachloride both at atmospheric and superatniospheric pre-awe. Eight new 2,1,6- t ris(chlorofluorometh>1)-1,3.5- triasiiie- +I ere obtained. Ph?sical constarits arid experimental data are reported.
RI.AZISES have been reported t o exhibit exceptional staT b ility . to heat and hydro1 ( Z ) , and it was believed that introduction of fluorine should increase stability and result in nonflaniniable compounds n-ith a wide liquid range Tvhicli might be suitable as heat transfer agents. T h e allylic nature of the chlorine atoms t o be substituted made the knon-n 2,4,6-tris(trichloroinethyl)-l,3,5-triazine relatively easy to fluorinate. The series of reactions used in the preparation of this intermediate follow: HC1
+ E t O H -+CClsCOzEt + HpO ether CClaC02Et + S H , -+CClJCOSH, + EtOH CC1,COSHZ + P,Oj +CC1,CS CC1,CO:H
3CC1,CS
HC1
ClsC-C'
,s\, C-CClS
(1)
(2) (3) (41
CCl, The 2,4,6-tris~trichloromethy1)-1,3,5-triazinewas fluorinated with anhydrous hydrogen fluoride and antimony pentachloride 1 Present address, California Research Corporation Standard Oil of California), Richmond, Calif.
(a subsidiary of
at both atmospheric and superatmo;phwic. preswrw. Tnhle I give. the compounds prepared, their physical pi,opeitieG, :~ndtheir 1i:ilogen analyse;. 2.1,6-TRIS(TRICHLORO\IETHTL)-1,3,5-TRIAZINE
The series of recrctioni outlined previously is descritied, and optimum yields are reported. Tiventy-two hundred fifty grami i13.8 moles) of trichloroacetic acid and 3200 grains (TO moles) of absolute etlinnol \\-ere placed in a 12-liter flask equipped n.ith a reflux conden5er. Ten milliliterR of concentrated hydrochloric acid were added, and the f l a ~ kivas heated for 6 hours a t reflux temperature. The reaction misture was then distilled a t atmospheric p i e s u r e through a short Vigreux column. T h e fraction tioiling a t 162-165' C. (750 mni. mercury) was collected HS ethyl trichloroacetate, boiling a t 164.0 C. Tn-enty-one hundred seventy-five grams (11.4 moles) of the eater were obtained; t h e yield and conver-ion \\-ere837,. Twenty-one hundred seventy-five grams (11.4 moles) of ethyl trichloroacetate n-ere diGsolved in 2 liters of anhydrou. diethyl ether, and the solution was placed in a three-neck 5-liter fiask equipped n-ith a gas inlet tubc. T h e solution was cooled t o ice temperature, and anhydrous ammonia was bubbled slowly into the reaction niisture over a period of 20 hours. Trichloroacetamide separated inimediately from solution. T h e flow of ammonia \\'as then stopped and the reniaining liquid removed by distillation. Sixteen hundred thirty grams (10.4 mole>) of trichloroacetaniide were obtained; the yield and conversion were
917,. S i n e hundred seventy-tn-o grams (6.0 moles) of triehloroacetamide and 284 grams (2.0 moles) of phosphorus pentoxide were intimately mixed, and the mixture was placed in a 3-liter distilling flask. The flask and contents were heated electrically with a Glascol heating mantle placed around the flask. T h e reaction proceeded smoothly, trichloroacetonitrile distilling from t h e reaction mixture as rapidly as formed. Additional amounts of phosphorus pentoxide were introduced during the reaction until a total of 994 grams (7.0 moles) had been added. Seven hundred
INDUSTRIAL A N D ENGINEERING CHEMISTRY
392
TLBLE I. Cotiipiiuiid CsHsFs CePU'sFsCI CsNaPiCl? Ceh-sFsC13 CsSsFsClr CeSaF4Cla CeNsF3Cls Csl\'sFrCl;
S E W C O \ l P O L - X D s D E R I V L D FROM 2 , ~ , 6 - T R I V E T H Y L - 1 , 3 , 3 - T R I I Z I \ E
R.P., c.
(748 ~ I R I . ) F.P., O C . 98.3-96.5 119.0-119.2 145.1-145.3 166.6-166.8 194.2-194.4 217.0-217.2 246 1-248.3 274.5-274.7
-24.8 -51.6 -36 2 -21.1 9.4 -10.2 9.6 14.0 960
71;'
1.3231 1.3540 1 3837 1.4129 1 4420 1.4611 1.4920 1.5009
di6 1.5857 1.6090 1.6234 1.6468 1.6656 1.6860 1.7134 1.7400
~ 3Iol. I V_ r. 'Theoretical Found 285 301.5 318 334.5 351 367.5 364 400.5 433.5
285 300 317 332 348 365 380
~_ r;_CI _ Theoretical Found 0.0 11.8 22.3 31.9 40.5 48.2 55.5 62.0 73.9
0.0 11.7 22.4 31.8 40.5 48.1 55.4 61 9 14.0
_ ;[ F Theorerical Found 60.0 50.6 41.9 34.1 27.1 20.7 14.8 9.5
60.3 50.7 41.7 34.4 27.2 20.6 15 0
Vol. 39, No. 3 mole) of 2,4,6-tris(trichloromethyl)-1,3,5-triazine and 50 grams (0.17 mole) of antimony pentachloride placed in a Of
One
liter capacity. TIVOhundred grams (10.Omoles) of anhydrous hydrogerl fluoride into the reaction vessel from a ,, , 9.8 csssc19 ... ... ... ... . ... small steel container, and the reactor was placed in a mechanical rocker. A reaction temperature of 169' C. ivas mainthirty-four grams (5.1 moles) of trichloroacetonitrile boiling at tained fur 24 hours, the pressure rising t o 2300 pounds per 84 O C. (760 mm.) were obtained. T h e yield and conversion were square inch. T h e autoclave was cooled t o room temperature, 85%. and gases \yere bled off into a n aqueous sodium hydroxide soluTrichloroacetonitrile was polymerized in the presence of anhytion. The reaction product was poured from the autoclave, drous hydrogen chloride following the directions of Dachlauer (I). treated with aqueous sodium hydroxide, and steam-distilled. Eleven hundred grams (7.4 moles) of trichloroacetonitrile were T h e diytillate !vas dried with calcium sulfate and rectified. Five placed in a nickel-lined autoclave of one liter capacity. The refraction.; were obtained and identified as: 2,4,6-(dichloroheptaaction vessel was charged with anhydrous hydrogen chloride t o fluorotrimetliylj - 1,3,5- triazine, 2,4,6 - (trichlorohexafluorotri800 pounds per square inch pressure and rocked a t room temperametliyl)-1,3,~-triazine, 2,4,6-(tetrachloropentafluorotriniethy1)ture for 100 hours before hydrogen chloride vas allowed to e+ 1,3,5- triaziiic, 2,4,6 - (pentachlorotetrafluorotrimethyl) - l j 3 , 5 cape and t,he vessel opened. T h e solid product was then removed triazine, and 2,~,6-(hexaclilorotri~uorotrimctliyl)-l~3,5-t~i~~zine. from the autoclave with ether solvent. One thousand t,wentyOne hundred seventy-eight grains of crude fluorinated product six grains (7.1 moles) of 2,4,6-tri~(trichloroinetli~-l)-1,3,5-triazine Tvei-e obtained; the yield and conversion xvere 85%. were obtained (melting point 96.0" C.). T h e yield and converAn esperinient similar to t h e preceding \\-as performed at sion were 'J6a/,. S o unreacted nitrile was found. The yield and 240" C.; reaction time was 24 hours, and t h e p r e p u r e reached 3300 conversion t o polymer, based on t h e trichloroacetic acid used, pounds per square inch. Rectification of the reaction product n-ere 60%. Distillation of t h e nitrile prior t o polymerization was yielded four fractionq: 2,4,6-tris(t~rifluorometliyl)-1,3,5-triazine, necessary for obtaining high yields. Experiments conducted 2,4,6-(chloro-octafluorotrirnethyl)-1,3,5-triazine~2,4,6-(dichloroKith crude t,richloroacetonitrilegave little or none of the desired heptafluorotrimethylj-l,3,5-triazine,and 2,4,6-(trichlorohexapolymer. fluorotrimethy1)-1,3,5-triazine.One hundred forty grams of crude fluorinated product Ivere obtained; the yield and conversion F LUORISATION were 757,. T h e 2,4,6-tri~(trichlor0methyl)-1,3~5-triazine used as starting PROPERTIES material in t h e fluorination experiments was the rrude product Fluorination of tri~(trichloroniethy1)triazines i i apparently from t h e polymerization reaction. It I Y ~ Yfound t h a t recrystalaccomplished a< readily as fluorination of tris(trichloromethy1) lization of the product was unnecessary before fluorination. The benzenemospheric and apparent physiological effects. A burning sensation in t h e upper superatmospheric pressures. For the fluorination conducted a t respiratory system was experienced upon inhalation of t h e comstmospheric pressure, 417 grams (0.97 mole) of 2,4,6-tris(trichlopounds, but no further investigation of this phenomenon was rometliyl)-1,3,5-triazine and 75 grams (0.25 mole) of antimony attempted. pentachloride were placed in a vertical vessel constructed of 2All of the compounds were insoluble in acids. This is due t o inch nickel pipe, 21 inches in length. T h e bottom end was t h e substitution of halogen for hydrogen atoms on the carbons closed, and t h e top was fitted with a thermocouple well and wateradjacent t o the nitrogen atoms, n-hich results in a reduction of cooled condenser of 1/2-inch nickel pipe, 13 inches long. An inlet basicity t o the point where t h e heterocyclic compounds, if basic tube was provided so t h a t hydrogen fluoride could be introduced at all, are no longer sufficiently basic to form hydroclilorides. below t h e surface of t h e material t o be fluorinated. T h e exit end T h e compounds give preliminary evidence of utility in the deof t h e condenser was connected b y a ',/*-inch copper tube t o a sired capacity as heat transfer agents. series of cooled nickel traps. T h e reactor vas placed in a n elecIn each case, the sample used for determination of physical tric heater and t h e reaction temperature held between 100" and properties and halogen analyses was purified by rectification in a 125' C. Five hundred grams (25.0 moles) of anhydrous hydrogen Podbielniak Hyper-Ca1 column. T h e boiling range of any >amfluoride were bubbled into t h e mixture over a period of 12 hours. ple was not more than 0.2' C. T h e product was then aerated and poured from t h e reactor. T h e material was treated with aqueous sodium hydroxide t o neutralACKNOWLEDGMENT ize any acids present and steam-distilled. T h e distillate was dried with calcium sulfate and rectified. Five distinct fractions Thanks are gratefully extended to t h e E t h y l Corporation for were obtained and identified as: 2,4,6-(trichlorohexafluorosponsoring t h e fellowship on which this work was accomplished. trimethy1)-1,3,5-triazine, 2,4,6-(tetrach1oropentafluorotrimethyl)1,3,5- triazine, 2,4,6 - (pentachlorotetrafluorotrimethylj - 1,33LITERATURE CITED triazine, 2,4,6-(hexachlorotrifluorotrimethyl)-1,3,5-triazine, and (1) Daclilauer, German Patent 682.391 (September 28, 1939) 2,4,6 - (heptachlorodifluorotrimethyl) - 1,3,5- triazine. One hun( 2 ) Widdige, J . p r a k i . Chem., [ 2 ] 33, 76-90 (1886). dred ninety-six grams of crude fluorinated product v e r e obtained; PRESENTED before t h e Symposium on Fluorine Chemistry aa parr o f yield and conversion n-ere 47%. paper 78, Division of Industrial and Engineering Chemktry, 110th hIeeting Fluorinations conducted at superatmospheric pressure were of A M E R I C I NCHE\rICAL SOCIETP, Chicago, Ill. .4bstracted from the doctoral conducted as follows: Two hundred seventeen grams (0.5 thesis of 0. R. Pierce. ,
