The risk of mixing dilute hydrogen peroxide and acetone solutions

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    The risk of mixing dilutehydrogen pacetone so

    The present study documents the enmixing diluteH2O2 and acetone so hehas been shown to be potentially 2 wexplosive peroxides. Mixing conc idshock and friction sensitive explo diasearch of the chemical literature ppinformation that addressed the p s wacetone solutions. The conclusion ingthan 3%H2O2 and 7% acetone, th nt athe presence of an acid catalyst, hu roTATP is relatively insoluble in wa levH2O2 solutions, thus any acetone catthe aqueous cleaning solution.

    Hydrogen peroxide mixed withorganic solvents is known to form dan-

    it is insoluble in water and is highlysensitive to friction, shock and tem-perature. It is called a primary explo-

    equal parts of acetonewith 10%H2O2.He found that TATP crystals were inso-luble in water, acids and alkalis but

    hly con-7. Theypingthetures ofs. Theby the

    ntainingblastingtion ory. Milasducts of

    2 2 ne with

    Jimmie CChemistRhode IUSA (Tefax: 401e-mail: j

    Joseph BChemistRhode required. One approach is introduc-tion of dilute aqueous hydrogen per-oxide (H2O2). A concern is that in ascrubber used to remove acetone fromprocess air, the combination of H2O2and acetone could form explosive per-oxides. To evaluate this concern, thesereagents were combined in acidic

    andwithout acid. They found that solu-tions of acetone and hydrogen peroxidein the presence of acid would predomi-nately form the trimer TATP. In theabsence of acid, 2,2-dihydroperoxypro-pane was formed and slowly convertedto [dioxybis(1-methylethylidene)]bis-hydroperoxide. Sauer and Edwards4

    Steven A. Wilson is affiliated with theEastman Chemical Company, King-sport, TN 37662, USA.

    James L. Smith is affiliated with theChemistry Department, University ofRhode Island, Kingston, RI 02881,

    1871-5532/$36.00 Division of Chemical Health and Safety of the American Chemical Society 27

    doi:10.101that other peroxide molecules can alsobe formed, including diacetone diper-oxide (DADP). Figure 1 provides themolecular structures and physicalproperties of TATP, DADP and otherperoxide products that are formedaccording to the literature.The potential for forming explosive

    peroxides when mixing dilute solu-tions of H2O2 and acetone has notbeen documented. Industrial scrub-bers are routinely used in chemicalplants. Periodic cleaning to removebio-sludge buildup inside the scrubber

    as acetone. Shanley and Grepreparedareviewarticleontheand chemical properties of higcentratedH2O2 solutions in 194provideda ternarydiagrammapdetonable compositions of mixacetonewaterH2O2 solutionexplosive power was measuredinspection of lead pipes co10 mL mixtures initiated bycaps. There was no identificaisolation of TATP in this studandGolubovic3 studied the prothe reaction of H O and aceto

    . Oxley is affiliated with thery Department, University ofsland, Kingston, RI 02881,l.: 401 874 2103;874 2103;

    rady is affiliated with thery Department, University ofsland, Kingston, RI 02881,gerous peroxides. Hydrogen peroxide sive due to its ease of detonation. Note, readily soluble in organic solvents suchenspan2


    INTRODUCTION6/j.jchas.2011.07.010eroxide anlutionsresults of a literature search and experimlutions. The use of diluteH2O2 to clean chazardous due to the reaction of H2Oentrated H2O2 and acetone with an acsives triacetone triperoxide (TATP) andwas unable to identify any directly a

    otential formation of explosive peroxideof these experiments is that when mix

    e solutions are unlikely to form significandreds of parts per million of organic peter, it is soluble at roughly the 15 ppmperoxides that are formed without acid

    and acetone is an especially hazardouscombination that can form variousexplosive peroxides when mixed athigh concentration while using an acidcatalyst.1,319 The primary explosivetriacetone triperoxide (TATP) is anoteworthy reaction product, becaused

    tal work to assess the risks ofmical vessels is common, but itith organic solvents to form

    catalyst is known to form thecetone diperoxide (DADP). Alicable research or technicalhen mixing dilute H2O2 anddilute solutions, such as lessmounts of TATP or DADP. Inxides can be formed. Althoughel and higher for acetone andalyst should remain soluble in

    media and alkaline media, and in thepresence of steel coupons containingwelding materials.Prior to experimental work, a com-

    prehensive literature search was con-ducted. Wolffenstein first reported theformationofTATPin1885whenmixing

    1Elsevier Inc. All rights reserved.

  • [(Figure_1)TD$FIG]

    H O





    hyl. = # 1





    CAS# 2614-7

    3,3,6,6-tetramethyl-1(Diacetone Diperostudied the formation of 2,2-dihydro-peroxypropane at various pH values.The work provided reaction kineticsparameters, but there was no mentionof TATP or DADP. They later studiedthe formation of higher adducts, butonly proposed that TATP is formed bya reaction between acetone and [dioxy-bis(1-methylethylidene)]bis-hydroper-oxide.5 Evans et al.6 described, in aforensic science case study, how easilyTATP is formed by mixing acetone, 6%H2O2 and concentrated sulfuric acid. Areview by Mackenzie7 addressed thehandling and use of H2O2, and stressedsafety precautions necessary at variousstrengths. There was no mention ofTATP, but he did warn against thebuildup of gases, including oxygen, asH2O2 degraded. In addition, therewerewarnings that after the reaction oneshouldbecautiousduringprocess steps,such as distillation, that would concen-trateanyunstableperoxidecompounds.A 1991 review byMackenzie8 provided

    CAS# 1073-91M.P. = 133 - 135

    Vapor Pressure (298 K) =

    Figure 1. Re

    28HO OH +





    ydroperoxidepane) [dioxybis(1-methyletM.P


    ,5-tetroxanee, DADP)safety considerations for processdesigns that use H2O2 and organic che-micals. It highlighted various risks,including the dangers from decomposi-tion of H2O2, as well as a variety ofproduction hazards. U.S. patent5,003,1099 describes a process ofdestroying acetone peroxides formedduring phenol synthesis by heating,decreasing pH, and adding a coppercompound. The work implies that thechemical destruction of acetone perox-ides would require conditions difficultto achieve during industrial processing.In1999,Bellamy10 foundthatonecouldchemicallydestroyTATPby refluxing inethanol containing tin(II) chloride.They also report that TATP is almostas powerful as trinitrotoluene (TNT),but is extremely sensitive to frictionand impact sensitivity tests. TATPis quite soluble in chloroform(42.7 wt%), toluene (28.6 wt%), acet-one (17.2 wt%), and hexane(14.4 wt%). Jiang et al.11 described the

    -2C (17) 17.7 Pa (17)

    3,3,6,6,9,9-hexamethy(Triacetone Tr

    CAS# 1M.P. =

    Vapor Pressure (

    action Products of Hydrogen Peroxide and

    Journal of ChemO OOH




    idene)]bis-hydroperoxide34C (3)471-09-6preparation of tetrameric acetone per-oxide (CAS #74515-93-8). They claimthat SnCl45H2O or SnCl22H2O couldact asacatalyst to forma tetramer.Theirresults indicate that no reaction takesplace when treating acetone with 30%H2O2 and no catalyst, but when0.5 mmol of catalyst was added, a>19% yield of tetrameric acetone per-oxidewasformed. In2002,Oxleyetal.12

    studied thedecompositionof TATPandconcluded that the predominantdecomposition product in the gas phaseismethylacetate. Inacondensed-phase,or within proton-donating solvents,TATP breaks down predominately intoacetone and water. Widmer et al.13

    developedanLC/MSmethodtoreplaceGC/MS methods, stating TATPdegrades GC columns. This paper alsoobserved that TATP has two structuralisomers, both stable at room tempera-ture. Their method was sensitive to10 ng per 100 mL (or 0.1 ppm).Schulte-Ladbeck et al.14 developed a

    l-1,2,4,5,7,8-hexoxonaneiperoxide, TATP)7088-37-894 C (17)298K) = 7.8 Pa (17)


    ical Health & Safety, March/April 2012

  • with an average linear velocity of117 cm/sec. The inlet was held at170 8C in the splitless mode for0.50 minutes at 2.37 psi before theinlet purged at 40.0 mL/minute. Themakeup gas to the mECD was UHPnitrogen run in the constant flowmodeat a rate of 30 mL/minute and thedetector was held at 280 8C. The ovenwas initially held at 40 8C for 2 min-utes, ramped at 20 8C/minute to150 8C and held for 1 minute, followedby a 0.50 minutes post run at 250 8C.The presence and quantity of TATP

    was determined bymatching the reten-

    kamp et al. (Figure 3).

    Solubility of TATP in Acetone andAqueous Acetone Solutions

    The solubilities of TATP and DADP inpure acetone were measured as151 mg/mL (0.191 mg/mg) and43 mg/mL (0.0548 mg/mg) respec-tively. TATP was found to have a solu-bility of 200 mg/mL (0.298 mg/mg) inchloroform. These values were deter-mined by adding solvent drop wise tothe solid peroxide while stirring in around-bottom flask. Qualitative solu-bility tests in aqueous acetone and





    General Experimental Set-Up

    A mix was defined as a combinationof hydrogen peroxide (initially50 wt%) and acetone (initially 100%)added to water to give hydrogen per-oxide concentrations that varied from30 wt% to 12 wt% to 3 wt% and theacetone concentrations of 50 wt% or7 wt%. Catalysts included various con-centrations of sulfuric acid, aqueoussodium hydroxide (50 wt%) or metalcoupons. The ability of the mix toform TATP was judged by gas chroma-tography (GC) analysis equipped witheither a mass selective detector (MSD)or an electron capture detector (ECD).If, after 48 hours, white solid precipi-tate was observed, the solids were col-lected, dried and analyzed by GC/MSto confirm their identity. If, after48 hours, no solid had formed, thesolutions were left for an additional 3to 6 days and extracted with chloro-form or dichloromethane, and theorganic extract was analyzed by gaschromatography.trace analysis method for TATP. Themethod uses liquid chromatography toseparate the analytes followed by post-column UV irradiation and derivativi-zation-based fluorescence detection.Denekamp et al.15 further describedthe two structural isomers of TATPand explained that a high transitionenergy step was the cause of the twoconformations being stable at roomtemperature. In 2004, Oxley et al.16

    developed procedures for training dogsto detect TATP. The work highlightsthat loss of TATP from surfaces is dueto its high rate of sublimation. In 2009,Oxley et al.17 studied the vapor densityof TATP. This work determines vaporpressures of both DADP and TATP(17.7 and 7.8 Pa at 25 8C). Dubnickovaet al.18 studied the decomposition ofTATP and determined that it is not anenthalpy-based explosion, but rather,an entropic burst in which four gasmolecules are created from one TATPmolecule. Eyler19 explored the solventeffects on the thermal decomposition ofTATP (1351708 C) and found that theratewaspositively influencedbysolventpolarity.Journal of Chemical Health & Safety, MarchAn Agilent 6890 gas chromatographcoupled with an Agilent 5973i Massselective detector (GC/MS), and anAgilent 6890 gas chromatographcoupled with a micro-electron capturedetector (GC/mECD), were employedto separate, identify andquantify TATP.The GC/MS was fitted with a 6-meterAgilent DB-5MS capillary columnwitha nominal diameter of 250 mm and filmthickness of 0.25 mm. The carrier gaswas UHP helium at an initial flow rateof 2.5 mL/min and an average linearvelocity 129 cm/sec. The inlet was runwith a 5:1 split at 170 8Cat a pressure of1.09 psi. The oven was held at 50 8C for2 minutes, ramped to 190 8C at 20 8Cper minute and the transfer line to theMSDwas held at 275 8C.To ensure thatall materials had passed through thecolumn, a 1 minute post run at 280 8Cwith a flow rate of 8 mL/minute wasused.The GC/mECD was fitted with a 6-

    meter Restek RTX-200 capillary col-umn with a nominal diameter of530 mm and a film thickness of1.50 mm. The carrier gas was UHPhelium at a rate of 15.8 mL/minute

    Calibration Curve for









    Figure 2. Calibration Cu/April 2012tion times and mass spectra of samplesto authentic standard solutions. A cali-bration curve for TATP was developedby dissolving a known amount ofauthentic TATP in dichloromethaneand preparing concentrations thatbracketed the amounts that wereexpected during an analytical run. Atypical set of concentrations for ananalytical run on the GC/MS was100, 200, 300, 400 and 500 mg/L ofTATP. A typical set of concentrationsfor an analytical run on the GC/mECDwas 0.5, 1, 2.5, 5, 10, 25, and 50 mg/L.A linear dependence was determinedby measuring the peak height or inte-grating the area under the character-istic peak for TATP and plotting thearea or height versus concentration(Figure 2).It should be noted that TATP chro-

    matograms exhibit two peaks, one foreach conformational isomer. Underthe GC conditions used in Figure 3,the isomeric peaks eluted 0.9 min-utes apart. When each peak was exam-ined by GC/MS, the mass spectra wereidentical, confirming that the twopeaks are isomers as reported byDene-


    P in Dichloromethane

    R2 = 0.9987


    ation TATP (mg/L)

    for TATP by GC/mECD.29

  • were combined, rinsed twice with10 mL of deionized water, dried overmagnesium sulfate and that solutionwas analyzed by GC/MS (Tables 2and 3).

    Mixing with Welded Steel Coupons

    Three types of steel coupons were eval-uated to determine the catalytic effectsassociated with formation of TATP.The three types were a coupon withouta weld, a coupon with a dirty weld,and a coupon with a clean weld. Asingle coupon of each type was placedin the six acetone/hydrogen peroxidemixtures. The reaction vessels weresealed and left at room temperaturesfor approximately 100 hours. An ali-quot was removed and analyzed byGC/MS as described above. Only the50%/30% and 50%/12% mixtures of


    Figure 3. Chromatograms of Authentic TATP Standard Solutions. From Top toBottom: 50, 25, 10, 5, 2.5, 1 mg/L TATP Standard Solutions.aqueous hydrogen peroxide are sum-marized in Table 1. Solubility wasdetermined by visual inspection.

    Mixing under Acidic Conditions

    Solutions for the acidic media condi-tions were prepared as follows; thewater necessary for dilution wasplaced in an Erlenmeyer flask, andthe flask was immersed in an ice bath.Hydrogen peroxide (0.10 mol) andthen acetone (0.10 mol) were addedto the chilled water in proportionssuch that the final concentration ofthe mixture mimicked the combina-tion of 30%, 12%, or 3% (w/w) hydro-gen peroxide with 50% or 7% (w/w)Table 1. Solubility of TATP in Various Solu

    TATP (mg) H2O Amount (kg) Aceton

    24.7 1.800025.6 1.600024.5 1.0000 1025.3 0.9999 1051 2.0001 1025.4 1.0001 1524.2 1.0000 1525.2 0.2504 7924.8 1.0002 2050.2 0.9999 1375.8 1.9999 1025.6 1.0316 9725 0.473725.2 0.400024.8 0.5000

    30acetone. Each of the six possible com-binations was prepared in triplicateand either 0...


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