Full Paper

Degradation of Triacetone Triperoxide (TATP) Using MechanicallyAlloyed Mg/Pd

Rebecca L. Fidler Albo, Tamra Legron, Michael J. Gittings, Mark R. Elie, Erin Holland Saitta, Michael E. Sigman,Cherie L. Geiger*, Christian Clausen

Department of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816-2366 (USA)

Received: January 20, 2009

DOI: 10.1002/prep.200900011

Abstract

A heterogenous catalytic system consisting of mechanicallyalloyed Mg/Pd particles has been used to degrade the peroxideexplosive, triacetone triperoxide (TATP). The degradation of theTATP with the Mg/Pd particles (half life of 1.2� 101 min) wascompared to the degradation with microscale Mg particles (halflife of 1.7� 103 min) and 10% Pd on activated carbon (half life of8.7� 102 min). Combining the Mg and Pd on carbon (Pd/C)through a mechanical alloying process is shown to producereactive particles that can be used to degrade TATP. The majorproduct of the degradation of TATP with mechanically alloyedMg/Pd particles was acetone. A material balance for carbon wasalso calculated for the degradation reaction with 94� 5%(mean� standard deviation) of the TATP carbons accounted forin the production of acetone.

Keywords: Degradation, Mg/Pd, TATP

1 Introduction

Triacetone triperoxide (TATP) is a cyclic peroxideexplosive that is readily synthesized using hydrogen perox-ide, acetone, and an acid catalyst [1]. TATP has beendetermined to have a high vapor pressure (�7 Pa) [2] and isespecially sensitive to decomposition from heat or friction,making it unsuitable for industrial production. TATP hasbecome more widely used in terrorist acts [3], as well asbeing used by non-industrial production [4] due to theavailability of reagents and its ease of synthesis. TATPcontamination can be found in areas of unregulatedproduction, targets of terrorist attacks, and confiscatedbulk materials, which could pose a threat to both the publicas well as law enforcement personnel.

The instability of TATP makes the clean-up of acontaminated area and confiscated bulk materials a chal-lenging problem resulting in the need for a safe and rapid insitu degradation and clean-up method. There has beenlimited research concerned with the degradation of TATP

which has included thermal decomposition over the temper-ature ranges of 151 – 230 8C [5], refluxing in toluene withSnCl2 [6], and exposing organic peroxides to copper at a lowpH [7]. The major products formed from the degradation ofTATP have included acetone and CO2. Although thesedegradation methods are successful in cleaving TATP toproduce non-explosive products, they do not obviate theneed for an in situ clean-up technique.

Mechanically alloyed Mg/Pd particles have been exploredin this paper as a reductive catalytic system that can degradeTATP to produce non-explosive byproducts. The mechan-ical alloying is a process that uses a mechanical alloyingprocess to combine the reductive properties of zero-valentmagnesium particles with a hydrogenation catalyst, Pd. Mg/Pd has been shown to successfully degrade organic halogens,such as polychlorinated biphenyls and trichloroethylene[8 – 10], thus Mg/Pd appears promising for the degradationof TATP [11, 12].

Combining Mg/Pd particles with technologies such asemulsified zero valent metal (EZVM) could provide apromising in situ method for the treatment TATP contami-nated areas. EZVM consists of metal particles contained inan aqueous inner membrane encased by an outer oilmembrane. The outer oil membrane of the EZVM hasbeen observed to absorb TATP crystals [11], which can thenbe degraded by Mg/Pd particles that are contained withinthe inner aqueous layer. Application of the EZVM tech-nology has been shown to successfully treat trichloroethy-lene contamination [13], thus EZVM technology using Mg/Pd particles presents a promising technique for the treat-ment of both wet and dry TATP contamination.

2 Experimental Section

2.1 Materials

The metals used to produce the mechanically alloyed Mg/Pd particles included: magnesium (2 – 4 mm diameter)* Corresponding author; e-mail: cgeiger@mail.ucf.edu

100 Propellants Explos. Pyrotech. 2010, 35, 100 – 104 � 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

purchased from Hart Metals, Inc. (Tamaqua, PA) and 1%palladium on carbon purchased from Engelhard (Iselin,NJ). Acetone, toluene, methanol (Optima� grade), concen-trated hydrochloric acid, and the 30% hydrogen peroxidesolution were all purchased from Fisher Scientific (Pitts-burgh, PA).

2.1.1 Metal Preparation

The optimal ball-milling process used was developed in-house [14]. Mg/Pd was prepared by ball-milling 78 g of Mgand 7 g of the 1% palladium on carbon for 30 min using aSeries 5400 Red Devil Paint Shaker. The metal and catalystloading were as follows: 91.8% Mg, 0.08% Pd, and 8.12% C.

2.1.2 TATP Preparation

Appropriate safety precautions are required in preparingthe TATP in the laboratory. One hundred microliters of bothacetone and 30% hydrogen peroxide were added to amicrocentrifuge tube on ice. Ten microliters of hydrochloricacid was added to the microcentrifuge tube, and the reactionwas allowed to sit on ice for 15 min. The reaction mixturewas then washed with 1 mL of a 1% sodium bicarbonatesolution to remove any residual acid, centrifuged anddecanted. The wash step was repeated until the washreached a neutral pH. The TATP crystals were thentransferred into an appropriate solvent. Literature hasreported that other products of this TATP synthesis hasshown as much as 30% impurity from hydroperoxy-termi-nated oligomeric peroxides [15], thus the TATP concen-tration of the solution was determined through a tolueneextraction and analysis using gas chromatography/massspectrometry (GC/MS) [16].

2.1.3 EZVM Preparation

EZVM was prepared using active metal (Mg/Pd parti-cles), corn oil, surfactant, and water as described in theliterature [13, 17].

2.1.4 Kinetic Studies

0,25 g of Mg, Mg/Pd, and 0.025 g of 10% Pd on C wereused to test the effectiveness of the metal in degradingTATP. TATP in a 4 : 1 water/methanol solution was exposedto the metal for the reaction times studied. To stop thereaction, the TATP was extracted from the aqueous layerand metal particles using toluene. The sample was hand-shaken for 2 min and then centrifuged at 1200 rpm for 4 min.The top layer was removed for analysis. All experimentswere performed in duplicate.

In the EZVM vial studies, 5 g of EZVM was added to10 mL of a water containing TATP. Solid phase micro-

extraction (SPME) was used to analyze the TATP concen-tration within the headspace above the aqueous and EZVMlayer. A 7 mm PDMS fiber was used for headspace samplingwith a sampling time of 1 min and a desorption time of1 min.

2.1.5 Analysis of TATP and Acetone

TATP was analyzed using a Thermo Trace GC equippedwith a DSQ Mass Spectrometer (MS). The GC was outfittedwith a 30 m Rtx-5� column (0.25 mm ID, 0.25 mm df) andhelium was used as the carrier gas at a flow rate of 1.2 mLmin�1. The sample was injected into a 110 8C injector port.The initial GC oven temperature was held at 50 8C for 1 minand then ramped at 10 8C min�1 until reaching a finaltemperature of 140 8C (held for 0.5 min). The transfer linewas held at 150 8C and the source temperature was set at150 8C. The MS was programmed for selective ion monitor-ing (SIM) of m/z 43, 59, and 75. Acetone was analyzed usinga Perkin Elmer Clarius GC with flame ionization detection(FID). The GC/FID was equipped with a Stabilwax�

capillary column (30 m, 0.53 mm ID, 1 mm df) using helium(5.2 mL min�1 flow rate) as the carrier gas. The sample wasintroduced into an injector held at 170 8C with a 2 :1 splitratio. The initial oven temperature was 50 8C (held for1 min), and then ramped at 10 8C/min until reaching a finaltemperature of 150 8C (held for 1 min).

3 Results

3.1 Kinetic Studies

The data obtained from the multiple kinetic experimentsusing the various metal particles tested are found inFigures 1 – 3. The degradation of TATP and the productionof acetone were compared to data obtained from experi-ments that had no metal particles present in which no TATPdegradation or acetone production was observed.

Figure 1. Degradation of TATP with micrometer-scale magne-sium particles.

Degradation of Triacetone Triperoxide (TATP) Using Mechanically Alloyed Mg/Pd

Propellants Explos. Pyrotech. 2010, 35, 100 – 104 � 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim www.pep.wiley-vch.de 101

Mg and Pd/C particles (Figures 1 and 2, respectively) weretested over a 4.5 h period, and a slight decrease in TATPconcentration was observed in addition to a slight increasein acetone concentration. The amount of Pd/C in the kineticexperiment found in Figure 2 had approximately 10 timesthe amount of Pd found in the mechanically alloyed Mg/Pd.

Initial testing of the Mg/Pd particle system was performedover a 4.5 h period similar to that of the Pd/C and Mgparticle testing, however approximately 90% of the initialTATP concentration was degraded within the first 30 minreaction time. Subsequent kinetic testing was executedwithin the first 30 min to provide additional data of thedegradation of TATP with Mg/Pd particles (Figure 3). Alldegradation data appear to follow a pseudo first-order ratelaw:

d½TATP�dt

¼ �kTATP½TATP� ð1Þ

The data obtained from these kinetic studies agrees withdata obtained from degradation of other analytes withcomparable metals [8 – 10]. The rate constants were ob-tained from fitting the data to the first-order kineticequation:

½TATP�½TATP�0

¼ e�kTATP ð2Þ

The rate constants (kTATP) obtained from the first-orderkinetic fitting are found in Table 1. The rate constants arenormalized to the metal concentration (rm). The half-lifedata for the degradation of TATP with the metal are alsocompared in Table 1.

Acetone was observed as the major product from thedegradation of TATP with the Mg/Pd particles. The molarratio of acetone produced to TATP degraded of the overallreaction was calculated from the kinetic data as 2.76 :1. Amaterial balance of carbon was also completed for thedegradation of the TATP using Mg/Pd (Figure 4). The totalC recovery was calculated as 94� 5% from the TATPdegradation reaction with Mg/Pd.

The suggested reaction pathway for the degradation ofTATP with Mg/Pd particles is shown in Scheme 1. Mg isoxidized in the presence of a protic solvent (water ormethanol) to form molecular hydrogen. Molecular hydro-gen is adsorbed onto the Pd surface. The hydrogen isavailable to react with the TATP molecule to form a

Figure 2. Degradation of TATP with 10% Pd on activatedcarbon.

Figure 3. Degradation of TATP with Mg/Pd particles.

Table 1. Normalized rate constants and half-lives for the degradation of TATP.

Metal Metal Concentration (rm) Normalized Rate Constant Half Life(g L�1) (L g�1 min�1) (min)

Mg 5.0� 101 8.0� 10�6 1.7� 103

Pd/C 5.0� 100 1.6� 10�4 8.7� 102

Mg/Pd 5.5� 101 1.2� 10�3 1.2� 101

Figure 4. Carbon material balance for the degradation of TATPwith Mg/Pd particles.

Full Paper R. L. Fidler Albo, T. Legron, M. J. Gittings, M. R. Elie, E. Holland Saitta, M. E. Sigman, C. L. Geiger, C. Clausen

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hydrated acetone. The loss of water then forms the endingproduct acetone.

3.2 EZVM Studies

Initial studies were performed to test the ability of EZVMto remove TATP from an aqueous solution. The data fromthis study is found in Figure 5. Approximately 90% of theinitial TATP is removed from the aqueous solution after24 h. This initial testing of EZVM for the removal of TATP ispromising for the clean-up of aqueous TATP samples.EZVM was also observed to absorb dry TATP crystals thusEZVM could also be applied to dry crystals.

4 Conclusion

Mechanically alloyed Mg/Pd has been shown to success-fully degrade TATP. The normalized rate constant obtainedfrom the reaction of TATP with Mg/Pd is approximately oneand three orders of magnitude greater than that of Pd/C andMg rates, respectively. The reaction of TATP with Pd/C inthe absence of molecular hydrogen may suggest a differentmechanism than that seen with the mechanically alloyedMg/Pd which must be further investigated.

The major product of the reaction of TATP with themechanically alloyed Mg/Pd was determined to be acetone.A material balance for carbon was completed accounted for94 � 5% of the carbons in TATP being degraded to formacetone.

Initial testing was completed to determine if Mg/Pd usedin combination with remediation technologies such asEZVM would be effective in removing TATP from aqueousmedia. EZVM removed 90% of the TATP concentrationwithin 24 h thus combining Mg/Pd with EZVM appearspromising for the in situ treatment of TATP.

5 References

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[6] J. A. Bellamy, Triacetone Triperoxide: Its Chemical Destruc-tion, J. Forensic Sci. 1999, 44, 603.

[7] M. Costantini, Destruction of Acetone Peroxides. U.S. Patent5003109, 1989, Rhone-Poulene Chimie, France.

[8] E. Hadnagy, L. M. Rauch, K. H. Gardner, Dechlorination ofPolychlorinated Biphenyls, Naphthalenes and Dibenzo-p-dioxins by Magnesium/Palladium Bimetallic Particles, J.Environ. Sci. Health, Part A: Toxic/Hazard. Subst. 2007, 42,685.

[9] R. DeVor, K. Carvalho-Knighton, B. Aitken, P. Maloney, E.Holland, L. Talalaj, R. Fidler, S. Elsheimer, C. A. Clausen,C. L. Geiger, Dechlorination Comparison of Mono-substitut-ed PCBs With Mg/Pd in Different Solvent Systems, Chemo-sphere 2008, 73, 896.

[10] U. D. Patel, S. Suresh, Dechlorination of ChlorophenolsUsing Magnesium-Palladium Bimetallic System, J. Hazard.Mater. 2007, 147, 431.

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[12] R. Fidler, C. L. Geiger, C. A. Clausen, M. E. Sigman,Degradation of TATP, TNT, and RDX, Proceedings of the10th Annual Consoil Conference, Milan, Italy, 3 – 6 June, 2008.

[13] J. Quinn, C. Geiger, C. Clausen, K. Brooks, C. Coon, S.O�Hara, T. Krug, D. Major, W.-S. Yoon, A. Gavaskar, T.Holdsworth, Field Demonstration of DNAPL Dehalogena-tion Using Emulsified Zero-Valent Iron, Environ. Sci.Technol. 2005, 39, 1309.

[14] B. Aitken, C. Geiger, C. Clausen, J. Quinn, VariablesAssociated With Mechanical Alloying of Bimetals for PCBRemediation, Proceedings of the 5th Annual InternationalConference on Remediation of Chlorinated and RecalcitrantCompounds, Monterey, CA, 22 – 25 May, 2006.

[15] M. E. Sigman, C. D. Clark, T. Caiano, R. Mullen, Analysis ofTriacetone Triperoxide (TATP) and TATP Synthetic Inter-

Scheme 1. Reaction pathway for the degradation of TATP withMg/Pd particles.

Figure 5. Removal of TATP from an aqueous solution usingEZVM.

Degradation of Triacetone Triperoxide (TATP) Using Mechanically Alloyed Mg/Pd

Propellants Explos. Pyrotech. 2010, 35, 100 – 104 � 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim www.pep.wiley-vch.de 103

mediates by Electrospray Ionization Mass Spectrometry,Rapid Commun. Mass Spectrom. 2008, 22, 84.

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Symbols and Abbreviations

TATP Triacetone triperoxideMg/Pd Ball-milled magnesium and palladiumPa Pascal8C Degree Celsius

SnCl2 Tin chlorideCO2 Carbon dioxidePd PalladiumEZVM Emulsified zero valent metalMg MagnesiumC CarbonGC Gas chromatographyMS Mass spectrometryFID Flame ionization detectorm Metermm MillimeterID Internal diametermm Micrometerdf Diameter of film thicknessmL Millilitersmin MinuteSIM Selective ion monitoring

Full Paper R. L. Fidler Albo, T. Legron, M. J. Gittings, M. R. Elie, E. Holland Saitta, M. E. Sigman, C. L. Geiger, C. Clausen

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