REPORT DOCUMENTATION PAGE

Transcription

1 REPORT DOCUMETATIO PAGE Form Approved OM o Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington eadquarters Services, Directorate for Information Operations and Reports ( ), 1215 Jefferson Davis ighway, Suite 1204, Arlington, VA Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OM control number. PLEASE DO OT RETUR YOUR FORM TO TE AOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) riefing Charts 4. TITLE AD SUTITLE 5a. COTRACT UMER Green bipropellants: Ionic liquids that are hypergolic with hydrogen peroxide 6. AUTOR(S) S.F. Deplazes; S. Schneider; T.W. awkins; and J.D. Mills 5b. GRAT UMER 5c. PROGRAM ELEMET UMER 5d. PROJECT UMER 5f. WORK UIT UMER PERFORMIG ORGAIZATIO AME(S) AD ADDRESS(ES) 8. PERFORMIG ORGAIZATIO REPORT UMER Air Force Research Laboratory (AFMC) AFRL/RZSP 10 E. Saturn lvd. Edwards AF CA SPOSORIG / MOITORIG AGECY AME(S) AD ADDRESS(ES) 10. SPOSOR/MOITOR S ACROYM(S) Air Force Research Laboratory (AFMC) AFRL/RZS 11. SPOSOR/MOITOR S 5 Pollux Drive UMER(S) Edwards AF CA AFRL-RZ-ED-VG DISTRIUTIO / AVAILAILITY STATEMET Approved for public release; distribution unlimited (PA #12169). 13. SUPPLEMETARY OTES For presentation at the 243 rd American Chemical Society (ACS) ational Meeting, San Diego, CA, March 2012) 14. ASTRACT This presentation covered an overview of AFRL s rocket propulsion laboratory and discussed hydrazine as a state-of-the-art rocket fuel, objectives for ionic liquids as bipropellant fuels, anion control of hypergolic activity, work on shorter ID times with a green(er) mindset, the reliability of ignition delay times, how test procedures affect ignition delay, the green flame, first approaches to green(er) hypergols, requirements for a green(er) oxidizer, what else is out there, and the challenge of borohydride anions in ionic liquids. 15. SUJECT TERMS 16. SECURITY CLASSIFICATIO OF: 17. LIMITATIO OF ASTRACT a. REPORT Unclassified b. ASTRACT Unclassified c. TIS PAGE Unclassified 18. UMER OF PAGES SAR 33 19a. AME OF RESPOSILE PERSO Dr. Tom W. awkins 19b. TELEPOE UMER (include area code) /A Standard Form 298 (Rev. 8-98) Prescribed by ASI Std

2 Green bipropellants: Ionic liquids that are hypergolic with hydrogen peroxide 243rd ACS ational Meeting San Diego California March 25, 2012 S. Deplazes Edwards AF, CA DISTRIUTIO A: Approved for public release, distribution unlimited

3 Where are we located? California, I thought California and California and California. Two-piece swimsuits and liquor and lawyers. 100 miles orth-east of Los Angeles Images: ASA satellite photo of Edwards Air Force ase, taken from This file is in the public domain because it was created by ASA. ASA copyright policy states that ASA material is not protected by copyright unless noted ; The Center for Land Use Interpretation Distribution A: Public Release, Distribution unlimited

4 ydrazine A State of the Art Rocket Fuel ydrazine Monomethylhydrazine ydrazine fuel vapor toxicity can increase testing/operations costs: System andling/fueling by certified crews in high level PPE Monitoring system in field Vapor toxicity can limit transportation options Ionic Liquid fuels can eliminate vapor toxicity and possess acceptable safety properties Distribution A: Public Release, Distribution unlimited

5 Objectives for Ionic Liquids as ipropellant Fuels Image: ASA Ignites on contact (ypergolic) Ignites Fast (<10ms) Ignites Fast & Green(er) Distribution A: Public Release, Distribution unlimited

6 Anion Control of ypergolic Activity a) b) c) d) Oxygenated Fuel-Rich ot ypergolic! ypergolic! O O O Only hypergolic with nitric acid!!! C C

7 Work on shorter ID times with green(er) mindset Ignites hypergolic, <10ms

8 ow reliable are ignition delay times? o two laboratories will report the same ignition delay times (different test-setups result in e.g. different speed and efficiency of mixing) General agreement in ranking propellant combinations Distribution A: Public Release, Distribution unlimited

9 Test procedures affect ignition delay TMAZ DCA * TMAZ CA * Me Me Me 3 Me Me Me 3 O 2 In over a hundred drop tests The ignition delay were reported between 20 and 40 ms based on ~ 100 drop tests Shreeve reports 8 ms for TMAZ CA Reactivity can be dependent on test procedures to the extremes of: o ignition observed with 21 G needle Ignition with 18 G needle *Shreeve, J.M. et. al. Inorg Chem. 2010, 49, 3282 Distribution A: Public Release, Distribution unlimited

10 The GREE Flame Ignition delay [ms] Decomp. onset [ C] Again Only hypergolic * C 5 nd with nitric acid!!! * C * C ** ** ** C C 2 C C C C * Remarkable impact of cation structure on reactivity Environmentally enhanced hypergolic ionic liquids, T. awkins, S. Schneider, L. udgens, M. Rosander Invention Disclosure, Feb 4, 2010; Provisional Patent Application, June 17, Y. Zhang, J. M. Shreeve, Angew. Chem. 2011, 123, ; ** Angew. Chem. Int. Ed. 2011, 50,

11 First approaches to green(er) hypergols Ignites hypergolic, <10ms & green(er)

12 Requirements for a Green(er) Oxidizer Storable! (non cryogenic) igh performing! Desirable Can be served as a refreshing drink Distribution A: Public Release, Distribution unlimited

13 What s Out There? WATER! itric Acid (extremely corrosive) 2 O 4 (less corrosive, high toxicity combined with high vapor pressure) 2 O 2 (less toxic vapor and less corrosive, environmental benign decomposition products) Distribution A: Public Release, Distribution unlimited

14 Anion Control of ypergolic Activity Liquid Oxidizer Commercially available solutions of Li hydrides and Li 4 in ethers are hypergolic with 2 O 2. a) J.J. Rusek, Proceedings of the 2nd International Conference on Green Propellants for Space Propulsion (ESA SP-557), Sardinia, Italy June 2004; b) T.L. Pourpoint, J.J. Rusek, 5th International ydrogen Peroxide Propulsion Conference, Purdue University, West Lafayette, I, September 2002.

15 orohydride Anions in Ionic Liquids A Challenge! Report on first borohydride RTIL (imidazolium based.) Tetrahedron Letters 49 (2008) * IL product is highly viscous. When 100% pure it might be solid. Questionable stability. ** R' R' R' R a 4 R C 2 C6 5 I C + R 2 C6 5 C 2 C6 5 * Y. Zhang, J. M. Shreeve, Angew. Chem. 2011, 123, ; Angew. Chem. Int. Ed. 2011, 50, 935. ** E.F. Godefroi, J. Org. Chem. 1968, 33, 860.

16 Anion Control Of Liquid Range Liquid Oxidizer ILs based on A anions DISTRIUTIO A: Approved for public release; Distribution unlimited

17 ( 4 ) PROMOTES LIQUIDUS A viscous oil crystallizing very slowly, from which neither 2, 2 6, nor ( 4 ) 3 could be removed even by pumping at 60 C. Melting point depression of 75 C. m.p C m.p. 50 C

18 Trihexyltetradecylphosphonium tetrakis(tetrahydroborato)aluminate 4 11 MR of R 4 PA P Raman R 4 P 4 R4PA n

19 Drop Test Results with ydrogen Peroxide and other Oxidizer Fuel\Oxidizer 90% 2 O 2 98% 2 O 2 2 O 4 WFA R 4 P ( 4 ) 4 Ignition Ignition Ignition Explosion Ignition Delay < 30ms < 30ms Vapor ignition - Green ipropellants: ydrogen-rich Ionic Liquids that Are ypergolic with ydrogen Peroxide Stefan Schneider, Tom awkins, Yonis Ahmed, Michael Rosander, Leslie udgens, Jeff Mills Angew. Chem. Int. Ed. 2011, 50, DISTRIUTIO A: Approved for public release; distribution unlimited

20 Anion teration C C C and competing over C and wants C by 14kcal/mol

21 Cyanoborohydride coordination 72 C 22kcal/mol 90 C <

22 X-ray crystal structure analyses as tool of characterization Me P C

23 Surprise! An all borohydride anion P C +?

24 A general path to tetrakis(tetrahydroborato)aluminates? C C + + +

25 What happened to ( 4 ) 2 3 C C C C C C + 2 2

26 A reaction pathway based on x-ray structures 3 C - + ( 4 ) ( 4 ) 2 3 C ( 4 ) 3 ( 4 ) - 4 ( 4 ) 2 3 C C - ( 4 ) 2 ( 3 C) C ( 4 ) 3 ( 4 ) ( 4 ) 2 ( 3 C) 2-3

27 [rel] [rel] 11 MR of reaction mixture C C C [ppm ] [ppm ]

28 Spiking reaction mixture with C Reaction Mixture, 11 MR, Proton Decoupled Reaction Mixture, 1 st addition of C Reaction Mixture, 2 nd addition C Reaction Mixture, 3 rd addition C C C C??

29 Single crystal X-ray structure analysis provided the answer A total of four different crystal shapes were identified under a microscope. Super thin plates are not a preferred crystal shape for X-ray analysis. Anion enlarged and rotated

30 [rel] The real picture of the crude reaction mixture [rel] [ppm ] C - 45 [ppm ] C C

31 eat of reaction calculations ( 4 ) [C 3 ] - 2 [( 4 ) 4 ] - + [(C 3 ) 3 ( 4 ) 2 ] 2- + (C 3 )( 4 ) [C 3 ] - + ( 4 ) 3 (C 3 )( 4 ) 2 + [ 4 ] ( 4 ) [C 3 ] - [( 4 ) 4 ] - + [(C 3 ) 2 ( 4 ) 2 ] ( 4 ) 3 + [C 3 ] - [(C 3 ) 2 ( 4 ) 2 ] [(C 3 ) 2 ( 4 ) 2 ] - + [C 3 ] - [ 4 ] - + [(C 3 ) 2 ( 4 ) 2 ] [(C 3 ) 2 ( 4 ) 2 ] - + [C 3 ] - [(C 3 ) 3 ( 4 ) 2 ] 2- * l values are kcal/mol, gas phase

32 The current reaction sequence 2[C 3 ] - + ( 4 ) 3 [( 4 ) 4 ] - + [( 4 ) 2 (C 3 ) 2 ] - exc C 3 - [( 4 ) 4 ] - + [( 4 ) 2 (C 3 ) 2 ] - [( 4 ) 2 (C 3 ) 3 ] 2-2 [C 3 ] - [ 3 C 3 ] -* + [C] - Summary and Conclusion The reactivity of aluminum borohydride is not always predictable Demonstrated dependence on the reaction partner and concentration It is challenging to characterize compound mixtures ew species need to be isolated and incorporated into IL s to evaluate their reactivity and physical properties * Emri, J et. al., Polyhedron, 1994, 13, 2353

33 Acknowledgement Tom awkins Jeff Mills Stefan Schneider Yonis Ahmed Air Force Office of Scientific Research (AFOSR) Michael erman