£63~S NAVAL SURFACE WEAPONS CENTER SILVER SPRI N P/ODTHE PH4OTOLYSIS OF FLUOROTRINITROMETNANE. gU)JIAN 8O0 bA CICNRA

7ULASSIFI ED NSWC /TR-79999 N

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NSWC TR 79-99

THE PHOTOLYSIS OF FLUOROTRINITROMETHANE

BY DOROTHY A. CICHRA

RESEARCH AND TECHNOLOGY DEPARTMENT

21 JANUARY 1980

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t~SW

~1 . INAVAL SURFACE WEAPONS CENTERDahlgren, Virginia 22448 0 Silver Spring, Maryland 20910

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REPORT DOCUMENT ATION PAGE B!? JRE CCV.PC$-.N~aFCr-"RER -.WMSEQ 2 GC.'1 ACESSICN. NO E0~'-:-A.G%..E

j NSWC/TR 7-99 - '

The Photolysis of Fluorotrinitromethane, Preliminary Report-6 PsEQVW,-AM CRIS R E=Zcl 4-

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A CT SR 7R.4N UMBER'N,

's Dorothy A. lCichra

S. 0SRCORMNG ORGANIZATION NAME AN-, AORSS. 10 AOREAM IEE4 6 OAR1 .M E

Naval Surface Weapons Center6l5N~O iWhite Oak 61O~O 15N;' ;0l

Silver Spring, Maryland 20910 I11 C-'RO..LING OFFICE NAME AND ADDRESS .' N12 REPOPT =-

4 -ICNIT:,RING A.3ENCV NAME &AODRESS'It djflerent from CanfrollI,,j 0211cC, NIi'tI"C.ASS. cif :h-o !.pofll

IUnclassified

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SCHEDULE

6. OISTRI13UTION STATEMENT (of this Report)

Approved for public release; distribution unlimited.

17. OISTRISUTION STATEMENT (of the abstract .. ,ier-d In Block 29, if d~fforent from~ Report)

18. SUPPLEMENTARY NOTES

19. KEY *OROS fContLinue, on reverse side it necessary wmd Identify by block rnumber)

PhotolysisFluorotri ni tromethaneFluo rod in itrome thane

2.0. ASSTAACT 'Contbnee or ,* * side It tIsc@U.Fy and fdofiif by block n~wber)

-the photolysis of fluorotrinitromethane was studied as a possible routeto fluorodinitromethane. The photolysis in hydroxylic solvents givesfluorodinitromethane in yields (non-isolated) rangirg from 25-500% under non-optimized conditions. Fluorodinitromethane apoears not to be formed in thephotolysis in non-hydroxylic solvents.

C0 1 7.473 EOON010 1~ .0 NO63 I OBSOLETE NEASFF5 'I___________________________________

SECURITY CL ASSI FICAT.ON01 OF -41S 04GE Cat ~8. Entered

NSWC TR 79-99

SUMMARY

Fluorodinitromethane is a key intermediate in the synthesis ofseveral energetic plasticizers containing the fluorodinitromethylgroup as energetic moiety. This report describes the basis of a newsynthesis for this compound which has significant advantages overexisting methods. The work was carried out under the NAVSWCIndependant Research Program, Task IR-201.

W. ENIGBy direction

NSWC TR 79-99

CONTENTS

PageI INTRODUCTION................................................ 3

II RESULTS AND DISCUSSION.................................... 3

II EXPERIMENTAL................................................ 5

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NSWC TR 79-99

I. INTRODUCTION

There is little work on the photolysis of fluorotrinitromethanereported in the literature. A flash photolysis study1 indicated thatunder some conditions the photolysis of fluorotrinitromethane jesultsin the formation of fluorodinitromethyl anion. It is reported thaton flash photolysis in absolute methanol an absorbtior with )max ofabout 375 nm appears, quickly reaching a maximum, and then decaying.This absorbtion was attributed to the fluorodinitromethyl anion. Themaximum absorbance observed is reported to correspond to a yield offluorodinitromethyl anion of about 1%. On the addition of sodiummethoxide to the photolyzed solution, an absorbance corresponding toa yield of fluorodinitromethyl anion of 11% was observed.

In a mixture of methanol and toluene, on the addition of sodiummethoxide to the photolyzed jolution, a yield of 3% of fluorodini-tromethyl anion wal observed . In acetonitrile no fluorodinitromethylanion was observed and no decrease in the amount offluorotrinitromethane was apparent.

Because of the reported I formation of the fluorodinitromethylanion in the flash photolysis, we decided to investigate thephotolysis of fluorotrinitromethane further to determine if it hadany use as an alternate synthetic route to fluorodinitromethane.

II. RESULTS AND DISCUSSION

The flash photolysis of fluorotrinitromethane in hydroxylicsolvents is reported to result in decomposition of the fluorotrini-tromethane (to an extent of 10-20%) to give an intermediate which wasidentified as the fluorodinitromethyl anion (in yields up to 10-15%).The results obtained in the present study are consistent with theearlier observations. When fluorotrinitromethane is irradiatedcontinuously with an unfiltered medium pressure mercury arc lamp in ahydroxylic solvent, it readily decomposes, resulting in the formationof fluorodinitromethane (as identified by gas chromatography andultraviolet spectroscopy).

lBalykin, V. P. and Slovetskii, V.I., "The Photochemistry of AliphaticNitro Compounds 3. Flash Photolysis of FluorotrinitromethaneSolutions" Izv. Akad. Nauk. SSSR, Ser. Khim., No. 9, 1976, p. 1970.

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Photolysis of fluorotrinitromethane in methanol results in theformation of fluorodinitromethane in 20-30% yield. Changing thesolvent to iso-propanol increases the yield while haveing little, ifany, effect on the rate of the photolysis. Photolysis in iso-propanolresults in the formation of fluorodinitromethane in about 50% yeild.

The yield of the fluorodinitromethane in methanol can also beincreased by the addition of acid to the solution to be photolyzed.Thus, photolysis of fluorotrinitromethane in methanol containingsulfuric acid (where the acid concentration is about four times thatof the fluorotrinitromethane) results in the formation of fluorodini-tromethane in about 50% yield.

The photolysis in methanol was also carried out using pyrexfiltered light. While the photolysis is slower in this case, theyield appears to be the same as with the unfiltered light.

The fluorodinitromethane appears to be the major product in theabove photolysis. Although there appear to be other products formed,no attempt was made to analyze the reaction mixture completely.Neither were any attempts made at optimizing the yield of thefluorodinitromethane or of isolating it.

The flash photolysis study1 of fluorotrinitromethane indicatedthat in non-hydroxylic solvents decomposition of the fluorotrinitro-methane did not occur. No decrease in the fluorotrinitromethane wasobserved in acetonitrile, and no intermediates were detected. Thepresent study revealed that, on continuous photolysis in non-hydroxylic solvents, fluorotrinitromethane does decompose; however,the decomposition occurs at a much slower rate than in hydroxylicsolvents. Only trace amounts, if any, of fluorodinitromethane isformed in these photolyses however.

Photolysis of fluorotrinitromethane in methylene chloride withunfiltered light for a time sufficient to completely decompose it ina hydroxylic solvent resulted in only about 20% decomposition of thefluorotrinitromethane. The major new components in the photolysismixture, observed by gas chromatography, were chloroform and a productthat appears to be fluorochlorodinitromethane. (It has the same gaschromatographic retention time as the product obtained by thereaction of fludrodinitromethane with chlorox. The product from thereaction of fluorodinitromethane and chlorox has an infrared spectrumconsistent with that reported 2 for chlorofluorodinitromethane.) Theorigin of the chloroform is unknown; however, photolysis for similartime periods of methylene chloride not containing fluorotrinitro-methane did not lead to formation of chloroform.

2Okhlobystina, L. V., et al. "Fluorination of Salts ofPolynitrohydrocarbons with Perchloryl Fluoride," Izv. Adad. Nauk.SSSR, Ser Khim., No. 7, 1971, p. 1,487.

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NSWC TR 79-99

Photolysis in acetonitrile for similar time periods again resultsin about a 20% decomposition of the fluorotrinitromethane. In thiscase, no new components were detected in the photolysis mixture by gIaschromatography under the conditions used to analyze the otherphotolyses.

Because of the much slower rate of photolysis in these non-hydroxylic solvents and the apparent lack of formation offluorodinitromethane, these photolyses were not investigated further.

III. EXPERIMENTAL

General. The photolyses were carried out using a medium pressuremercury arc lamp placed in a quartz cooling well. The solutions to bephotolyzed were placed in quartz tubes which were then positionedaround the outside of the cooling well at distances of about 3 to 4inches from the cooling well.

The photolyzed mixtures were analyzed for products on both a 5ft. 1/4 inch 10% fluorosilicone coluf1in and a 6 ft. 1/8 inch 10% UCCK982 column. Products were identified by comparison to authenticmaterial. However to minimize interference from the solvent, quanti-tative results were obtained for the photolyses in the hydroxylicsolvents on only the fluorosilicone column at 800C while those forthe photolyses in non-hydroxylic solvents were obtained on the UCCW982 column at ambient temperature.

The photolyses in hydroxylic solvents were also analyzed byultraviolet spectroscopy. (The method used was similar to thatfor analysis of fluorodinitromethanol 3). The photolyzedmixture was diluted with water (50 vL photolysis mixture to 10 mLwater). The resulting aqueous solution was then added to 0.01Msodium hydroxide (30 uL aqueous solution to 10 mL sodium hydroxide).The resulting solution was then analyzed immediately at 382 nm. Theconcentration (moles/liter) was calculated as the observed absorbance/19,400 for a 1 cm cell.

The photolyses were generally followed by gas chromatography, andwere stopped when most of the fluorotrinitromethane had decomposedto prevent further photolysis of any initially formed products.

Glover, D. J., Personal Communication.

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PHOTOLYSIS OF FLUOROTRINITROMETHANE IN METHANOL. Fluorotri-nitromethane (350 '4l) was dissolved in methanol (5 ml), then 3 ml ofthe solution was placed in a quartz tube and photolyzed for 8.5 hrs.Gas chromatography on the final solution revealed the presence offluorodinitromethane and two other small peaks of retention timesimilar to that of fluorotrinitromethane. All the fluorotrinitro-methane had decomposed. Analysis by uv spectroscopy indicated thatthe yield of fluorodinitromethane was 28%.

A photolysis of a similar solution in a pyrex tube for 7.5 hrs.resulted in about 80% reaction of the fluorotrinitromethane andformation of fluorodinitromethane in 22% yield (a 26% conversion).The same two other peaks present in the photolysis in quartz werepresent also.

PHOTOLYSIS IN METHANOL WITH SULFURIC ACID. Methanol was addedto 350 Ll of sulfuric acid to make 5 ml. To this was added 350 vil offluorotrinitromethan. then 3 ml of this solution was photolyzed ina quartz tube for 7.5 hrs. Gas chromatographic analysis indicatedthat about 96% of the fluorotrinitromethane had decomposed. The mix-ture crntained fluorodinitromethane and the same two other productsas in the photolysis in plain methanol. The yield of fluorodinitro-methane was 51% by uv spectroscopy.

PHOTOLYSIS OF FLUOROTRINITROMETHANE IN ISOPROPANOL.Fluorotrinitromethane (350 '4l) was dissolved in 5 ml of isopropanol,then 3 ml of the resulting solution was photolyzed in a quartz tubefor 5.75 hrs. No fluorotrinitromethane remained, and analysis by gaschromatography revealed the presence of fluorodinitromethane and oneother peak of retention time slightly shorter than fluorotrinitro-methane. Analysis of the mixture by uv spectroscopy indicated thatthe yield of fluorodinitromethane was 53%.

PHOTOLYSIS OF FLUOROTRINITROMETHANE IN METHYLENE CHLORIDE.Fluorotrinitromethane (100 'l) was dissolved in methylene chloride(5 ml), then 3 ml of the solution was photolyzed in a quartz tube for5.5 hrs. Gas chromatography indicated that 80% of thefluorotrinitromethane remained. Two other peaks were present, one waschloroform, the other appeared to be fluorochlorotrinitromethane.

PHOTOLYSIS OF FLUOROTRINITROMETHANE IN ACETONITRILE.Fluorotrinitromethane (100 ul) was dissolved in 5 ml ofacetronitrile, then 3 ml of the solution was photolyzed for 5.5 hrs.Gas chromatography indicated that 80% of the fluorotrinitromethaneremained. No other peaks were apparent.

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NSWC TR 79-99

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