Effects of acetone on methyl ethyl ketone peroxide runaway reaction

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Available online at www.sciencedirect.comJournal of Hazardous Materials 153 (2008) 10711077Effects of acetone on methylperoxide runaway reaTsin So-Kw, Nat6400niversan, ROber 2er 200AbstractRunaway t issurelease durin try (Dand with ace he kifitting. Through the reproducible tests in each condition, the results show that acetone is not a contaminant, because it could increase the activationenergy (Ea) and onset temperature (To) when combined with MEKPO, which differs from the hazard information of the material safety data sheet(MSDS). 2007 Published by Elsevier B.V.Keywords: R1. IntroduChemictiators andethyl ketont-hexyl hydon [1]. Ining in varibeen incurunstable chorder to aloperating pevolution itemperaturreported bying ignition Corresponfax: +886 5 5E-mail ad0304-3894/$doi:10.1016/junaway reactions; Methyl ethyl ketone peroxide (MEKPO); Differential scanning calorimetry (DSC); Acetone; Kinetic and safety parametersctional industries widely apply organic peroxides as ini-cross-linkers during polymerization, such as methyle peroxide (MEKPO), di-t-butyl peroxide (DTBP),roperoxide, cumene hydroperoxide (CHP), and sopractice, acetone is readily available for clean-ous applications. Historically, many accidents havered by MEKPO in Asia (Table 1); therefore, itsaracteristics need to be understood thoroughly inleviate the degree of hazard in manufacturing androcesses. If a reaction is exothermic and the heatn the system is greater than the heat loss, then thee will increase until all reactants are consumed, asZatka [2]. Kotoyori indicated that incidents involv-or explosion of thermally unstable substances mayding author. Tel.: +886 5 534 2601x4416/4499;31 2069.dress: shucm@yuntech.edu.tw (C.-M. Shu).occur due to failure of temperature control in process ves-sels [3]. In a systematic study, we have attempted to elucidatethe runaway reaction phenomena of MEKPO combined withacetone.In this area of thermal analysis, many related calorimetershave been employed to discover the unstable materials. Yu etal. use C80D to demonstrate the hazardous material of asphalt-salt mixtures (ASM) [4]. Stoessel applies DSC to evaluate thethermal stability of nitro-aromatics, and then obtains the safetyparameter of time to maximum rate (TMR) [5]. Miyake etal. use microcalorimetries for evaluating the thermal hazardof self-reactive substances of CHP in chemical processes [6].The accelerating rate calorimeter (ARC) also has been appliedto calculate the safety parameters reported by Whitmore andWilberforce [7]. By vent sizing package 2 (VSP2), Tseng etal. demonstrate that MEKPO is a sensitive material, especiallywhen mixed with inorganic acids [8] or contaminants [9]. Othermeasurement methods have been used in this area, includingisoconversion methods for estimating the activation energy [10].In this study, we attempted to elucidate the status of a runawayreaction for MEKPO in the presence of acetone. If acetone has see front matter 2007 Published by Elsevier B.V..jhazmat.2007.09.099Yan-Fu Lin a, Jo-MingTsung-Chih Wu c, Chi-Ma Department of Chemistry, National Chung Hsing University, 250 Kub Doctoral Program, Graduate School of Engineering Science and Technology123 University Road, Sec. 3, Douliou, Yunlinc Department of Industrial Safety and Health, Hungkuang UTaichung County 43302, TaiwReceived 20 March 2007; received in revised form 18 SeptemAvailable online 29 Septembreactions by methyl ethyl ketone peroxide (MEKPO) are an importang upset situations. This study employed differential scanning calorimetone 99 mass% on three types of heating rate of 2, 4, and 10 C/min; tethyl ketonectioneng b,hu b,ang Road, Taichung 40227, Taiwan, ROCional Yunlin University of Science and Technology,2, Taiwan, ROCity, 34 Chung-Chie Road, Shalu,C007; accepted 18 September 20077e in Asia, due to its unstable structure and extensive heatSC) to draw the experimental data for MEKPO 31 mass%netic and safety parameters were then evaluated via curve1072 Y.-F. Lin et al. / Journal of Hazardous Materials 153 (2008) 10711077NomenclatureA frequency factor (M1n/s)CpEaHkmniQRTTCLTMRT0TadzGreek leiTable 1Selected seve[11]Year Loc1979 Tai1996 Tai1964 Jap1978 Jap2000 Kor2001 Chi2003 Chibeen mixedcompared w2. Experim2.1. Stand31mass%MEKPOwhich had99 mass%,at 4 C. Afdata wereAfterwardsand safetyarranged an2.2. Differential scanning calorimetry (DSC)Temperonat c100re wrisonrmalmin,fromion.ultsof tined inby tspecific heat capacity (J/g K)apparent activation energy (kJ/mol)heat of reaction (J/g)rate constant (M1n/s)mass of reactant (mg)reaction order (unitless)caloric capacity of measuring cell from exother-mic substances (J/g)gas constant (8.314 J/mol K)temperature (C)time to conversion limit (day)time to maximum rate (h)exothermic onset temperature (C)adiabatic temperature rise (C)autocatalytic constant (unitless)formedcell thmatelysoftwacompater the10 C/chosencondit3. ResAllplayednot usraisedttersdegree of conversion (unitless)scanning rate (C/min)degree of conversion for second and third stages(unitless)re thermal explosion accidents caused by MEKPO in East Asiaation Injuries Fatalities Hazardwan (Taipei) 49 33 Explosion (storage)wan (Taoyuan) 47 10 Explosion (tank)an (Tokyo) 114 19 Explosionan (Kanagawa) 0 0 Explosionea (Yosu) 11 3 Explosionna (Jiangsu) 2 4 Explosionna (Zhejiang) 3 5 Explosionwith MEKPO, the degree of hazard can be decreasedith pure MEKPO.ental setupard procedure for preparation of MEKPOand acetone 99mass%31 mass% was purchased directly from Fluka Co.,been stored in a refrigerator at 4 C. Acetoneused as a diluent, was also stored in a refrigeratorter mixing of these two materials, the experimentaldetermined by DSC three times in each condition., curve fitting was employed to model the kineticparameters. Mass ratio of MEKPO/acetone has beend listed in Table 2.inhibitionreactions.4. Discuss4.1. CurveAccordiMEKPO isOO bondpositions. Tby autocataof the methA complexthird stages1st stage:ddt= A12nd stageddt= A23rd stage:ddt= A3When M99 mass%all reactionture (T0) in55.6 to 61.3also had bepeak; theseature-programmed screening experiments were per-a DSC (Mettler TA8000 system), and a measuringan withstand relatively high pressure to approxi-bar (DSC 821e) was used for the experiment. STAReas used to obtain thermal curves [12]. For preciseof the results of curve fitting and achieving bet-equilibrium, the scanning rate was set at 2, 4, andrespectively [13]. The range of temperature rise was30 to 300 C during the excursion of the test in eachhe experimental and curve fitting results are dis-Tables 2, 3 and 4 (these mixture conditions wereour previous studies). Aside from the informationhe literature and MSDS, our results indicated thephenomenon of acetone on the MEKPO runawayiontting analysisng to the experimental and curve fitting results,a thermally unstable material because of the weak. There were three exothermic peaks during decom-he first peak belongs to an n-order reaction, followedlytic reactions for the second and third. Advantagesod are demonstrated by Kossoy and Koludarova [14].model of consecutive reactions where the second andwere autocatalytic can be expressed by Eqs. (1)(3):eEa1/RT (1 )n1 n-order reaction (1):eEa2/RT ( )n2 (z + n3 )autocatalytic reaction(2)eEa3/RT ( )n4 (z + n5 )autocatalytic reaction(3)EKPO 31 mass% was combined with acetoneat three different heating rates (2, 4, and 10 C/min),s indicated that the first exothermic onset tempera-creased from 35.4 to 38.1 C, 43.6 to 79.2 C, andC, respectively. The apparent activation energy (Ea)en reduced during the mixture conditions for the firstphenomena can be readily seen in Figs. 1 and 2.Y.-F. Lin et al. / Journal of Hazardous Materials 153 (2008) 10711077 1073Table 2Thermokinetic parameters derived from the DSC data on MEKPO 31 mass% and mixed with acetone 99 mass% for the first peak of the reactionSample (C/min) T0 (C) Ea (kJ/mol) n1 n2 A (s1) z H (J/g)MEKPO 31 mass% (2.5 mg) 10 55.6 136.5 1.1 * 43.2 * 68.7MEKPO 31 mass% (3.2 mg) 4 43.6 119.3 0.9 * 36.5 * 65.6MEKPO 31 mass% (3.1 mg) 2 35.4 117.8 0.8 * 36.9 * 65.5MEKPO 31 mass% (2.2 mg) + acetone 99 mass% (1.0 mg) 10 61.3 138.0 1.0 * 42.9 * 76.2MEKPO 31 mass% (2.9 mg) + acetone 99 mass% (1.2 mg) 4 79.2 184.1 0.8 * 55.9 * 57.4MEKPO 31 mass% (2.5 mg) + acetone 99 mass% (1.0 mg) 2 38.1 120.2 0.7 * 37.8 * 66.3The first peak of the reaction. Calculated values based on experimental data from DSC tests. Estimated values are shown in bold. (*) Not applicable.Table 3Calculated thermokinetic parameters derived from the DSC data on MEKPO 31 mass% and mixed with acetone 99 mass% for the second peak of the reactionSample ol)MEKPO 31 mMEKPO 31 mMEKPO 31 mMEKPO 31 mMEKPO 31 mMEKPO 31 mThe second p sts. EsOne imporhazardousacetone 99combiningcompared wof 4 C/minpeak. Afterwere classireactions. Tto 202.7 J/g4, and 10 Ccondition,bined withdemonstratconditions.were the fir4.2. SafetyPracticaemployed trials that itemperaturon. Are tetersimuay reendexprAQCTable 4Calculated theSampleMEKPO 31 mMEKPO 31 mMEKPO 31 mMEKPO 31 mMEKPO 31 mMEKPO 31 mThe third pea (C/min) Ea (kJ/mass% (2.5 mg) 10 78.4ass% (3.2 mg) 4 59.4ass% (3.1 mg) 2 51.8ass% (2.2 mg) + acetone 99 mass% (1.0 mg) 10 78.2ass% (2.9 mg) + acetone 99 mass% (1.2 mg) 4 114.3ass% (2.5 mg) + acetone 99 mass% (1.0 mg) 2 56.2eak of the reaction. Calculated values based on experimental data from DSC tetant parameter that was employed to understand thecharacteristics is the heat of reaction (H). Whenmass% (about 1 mg) was doped into the test cell forwith the MEKPO 31 mass%, the H was reducedith the pure solution. Especially under a heating rate, the H decreased from 65.6 to 57.4 J/g in the firstthe first peak was induced, the second and third peaksfied as autocatalytic reactions, treated as unexpectedhe H also decreased from 320.9 to 284.7 J/g, 312.6, and 198.7 to 129.4 J/g under the heating rates of 2,/min, respectively. In terms of the third peak of eachthe H also was reduced while MEKPO was com-acetone, as indicated in Table 4. All of the resultse that an inhibitive reaction can be formed in mixingand sohas moparamto maxrunawTownslyticalTMR =Tad =As far as T0, H, and Ea are concerned, these resultsst to be reported on these issues.parameters analysislly speaking, many safety parameters could beo classify the degree of hazard for hazardous mate-s adopted, such as self-accelerating decompositione (SADT) [1518], temperature of no return (TNR),Howeven-order reaing autocaonly by apbeen used iFrom Fiwithin the twas decreathan the mirmokinetic parameters derived from the DSC data on MEKPO 31 mass% and mixed (C/min) Ea (kJ/mol)ass% (2.5 mg) 10 123.6ass% (3.2 mg) 4 130.8ass% (3.1 mg) 2 144.9ass% (2.2 mg) + acetone 99 mass% (1.0 mg) 10 103.7ass% (2.9 mg) + acetone 99 mass% (1.2 mg) 4 136.7ass% (2.5 mg) + acetone 99 mass% (1.0 mg) 2 122.1k of the reaction. Calculated values based on experimental data from DSC tests. Estimn1 n2 A (s1) z H (J/g)1.1 0.2 18.5 0.0186 198.70.9 0.5 12.5 3 103 312.60.9 0.7 10.1 0.0373 320.90.9 0.3 18.4 6.8 103 129.41.3 0.3 28.9 1.5 103 202.70.9 0.3 11.1 0.0142 284.7timated values are shown in bold. z: Autocatalytic constant [26].ccording to the experimental results, since MEKPOhan two exothermic peaks, both of these two safetyare not suitable for use in this study. In essence, timem rate (TMR) is used for determining the degree ofactions if an accident occurs. TMR was proposed byand Tou [19] in 1980, who derived convenient ana-essions (Eqs. (4) and (5)) for calculation purposes:RT 2EaTadeEa/RT (4)p(5)r, the formulas are valid only for simple single stagections. In the case of more complex reactions, includ-talytic reactions, TMR can be properly determinedplying kinetics-base curve fitting. This method hasn the present study.gs. 35, when MEKPO was combined with acetoneemperature range of 20100 C, the degree of hazardsed. Accordingly, pure MEKPO was more dangerousxed ones.with acetone 99 mass% for the third peak of the reactionn1 n2 A (s1) z H [J/g]0.8 0.5 25.6 0.0124 483.31.1 1.7 29.2 0.0945 359.10.4 0.4 31.9 0.0711 373.31.1 1.1 21.4 0.0385 436.10.5 0.4 29.6 0.0162 234.80.4 0.6 26.1 0.0125 330.4ated values are shown in bold. z: Autocatalytic constant [26].1074 Y.-F. Lin et al. / Journal of Hazardous Materials 153 (2008) 10711077Fig. 1. Comparison of experimental data on heat production for MEKPO 31 mass% and mixed with acetone 99 mass% with kinetics-based curve fitting results((1) MEKPO + acetone with scanning rate of 10 C/min for experimental data and curve fitting; (2) MEKPO with scanning rate of 10 C/min for experimental dataand curve fitting; (3) MEKPO + acetone with scanning rate of 4 C/min for experimental data and curve fitting; (4) MEKPO with scanning rate of 4 C/min forexperimental data and curve fitting; (5) MEKPO + acetone with scanning rate of 2 C/min for experimental data and curve fitting; (6) MEKPO with scanning rate of2 C/min for experimental data and curve fitting).For determining thermal stability, which is characterized bythe time necessary to reach a certain level of conversion at certainconstant temperature of time to conversion limit (TCL) [20],it was necessary to determine the stability of materials understorage or transportation conditions. From Figs. 68, within thetemperature range of 20100 C, the results revealed that pureMEKPO was more unstable than in mixed conditions. This wascontrary to the normal perception that acetone may exacerbatethe severity of hazards incurred by MEKPO in terms of runawayreactions.Fig. 2. Comp((1) MEKPOand curve fittexperimental2 C/min for earison of experimental data on heat production rate for MEKPO 31 mass% and mixewith scanning rate of 10 C/min for experimental data and curve fitting; (2) MEKPOing; (3) MEKPO + acetone with scanning rate of 4 C/min for experimental data andata and curve fitting; (5) MEKPO with scanning rate of 2 C/min for experimental dxperimental data and curve fitting).d with acetone 99 mass% with kinetics-based curve fitting results+ acetone with scanning rate of 10 C/min for experimental datad curve fitting; (4) MEKPO with scanning rate of 4 C/min forata and curve fitting; (6) MEKPO + acetone with scanning rate ofY.-F. Lin et al. / Journal of Hazardous Materials 153 (2008) 10711077 1075Fig. 3. TMR vs. temperature (kinetics-based curve fitting) for MEKPO31 mass% and mixed with acetone 99 mass% with heating rate of 2 C/min.Fig. 4. TMR31 mass% and.4.3. ReactMEKPObis-hydropinto severathe data ofenol radicaFig. 5. TMR31 mass% andFig. 6. Time to conversion limit (TCL) vs. temperature (kinetics-based curvefitting) for MEKPO 31 mass% and mixed with acetone 99 mass% with heatingrate of 2 C/min.vs. temperature (kinetics-based curve fitting) for MEKPOmixed with acetone 99 mass% with heating rate of 4 C/min.ion mechanism analysishas seven types of structures [21]. When MEKPO,eroxide, was heated gradually, it would decomposel free radicals, as shown in Fig. 9 [22,23]. Based onbond dissociation energy (BDE) listed in Table 5,ls appear to be more stable ones [24,25]. When thevs. temperature (kinetics-based curve fitting) for MEKPOmixed with acetone 99 mass% with heating rate of 10 C/min.Fig. 7. Timefitting) for MErate of 4 C/mdecomposiin Fig. 10, tmore stableintermediaThus, the raFig. 8. Timefitting) for MErate of 10 C/to conversion limit (TCL) vs. temperature (kinetics-based curveKPO 31 mass% and mixed with acetone 99 mass% with heatingin.tion of MEKPO is accompanied by acetone, as shownhese free radicals then could either be transformed toenol radicals, or produce less reactive nonperoxidetes (2-hydroperoxy-propan-2-ol or butane-2,2-diol).te of the decomposition of MEKPO is slowed down.to conversion limit (TCL) vs. temperature (kinetics-based curveKPO 31 mass% and mixed with acetone 99 mass% with heatingmin.1076 Y.-F. Lin et al. / Journal of Hazardous Materials 153 (2008) 10711077ms ofTable 5Bond dissociaBondCH3 HCH3CH2 HHO HCH3C(O)CH2X YG=ene5. ConcluA newcombinedand curveH, T0, anble solventMEKPO thous reactioreactive whH. SuchFig. 9. Proposed decomposition mechanistion energies for MEKPO and acetone [25]Dissociation energy (kJ/mol) Bond439 C H420 C C425 C OH 401 O OG=energy required to homolyse bondrgy released in combing radicals greater value means higher energy (more unstable) radicalX Y .Fig. 10. Proposed reaction mechanisms of MEKPO cosionsstudy of runaway reactions on MEKPO 31 mass%with acetone 99 mass% was accomplished by DSC,fittingrunaway reactions were explored. As far asd Ea are concerned, acetone was found to be a sta-, which mitigated the degree of severity in terms ofermal runaway. As such, it did not induce a danger-n by MEKPO. On the other hand, it was not thermallyen mixed and was found to be capable of reducinga modification in combining acetone with MEKPOmay haveardous chaAcknowledWe areSaint PeterAnthony Mneering, Frassistance.pure MEKPO.Average bond dissociation energy (kJ/mol)413348358146mbined with acetone.played an important role in understanding the haz-racteristics of pure MEKPO alone.gmentsindebted to Dr. Arcady A. Kossoy of ChemInformsburg (CISP), Ltd., St. Petersburg, Russia and Mr.. Janeshek of Dow Chemical, Global Process Engi-eeport, Texas, USA, for their considerable technicalY.-F. Lin et al. / Journal of Hazardous Materials 153 (2008) 10711077 1077References[1] A. Miyake, N. Yamada, T. Ogawa, Mixing hazard evaluation of organicperoxides with other chemicals, J. Loss Prev. Process Ind. 18 (2005) 380.[2] A.V. Zatka, Application of thermal analysis in screening for chemicalprocess hazards, Thermochim. Acta 28 (1979) 7.[3] T. Kotoyori, Critical ignition temperatures of chemical substances, J. 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Preparation,separation and identification of peroxides derived from methyl ethyl ketoneand hydrogen peroxide, J. Am. Chem. Soc. 81 (1959) 5824.[23] OSHA, methyl ethyl ketone peroxide organic method # 77, OccupationalSafety.[24] J. Clayden, N. Greeve, S. Warren, P. Wothers, Organic Chemistry, Oxford,UK, 2001, pp. 10201027.[25] D.R. Lide, CRC handbook of chemistry and physics, vol. 9, 86th ed., CRCPress, 2006, pp. 5576.[26] A.A. Kossoy, T. Hofelich, Methodology and software for assessingreactivity ratings of chemical systems, Pro. Saf. Prog. 22 (2003)235.Effects of acetone on methyl ethyl ketone peroxide runaway reactionIntroductionExperimental setupStandard procedure for preparation of MEKPO 31mass% and acetone 99mass%Differential scanning calorimetry (DSC)ResultsDiscussionCurve fitting analysisSafety parameters analysisReaction mechanism analysisConclusionsAcknowledgmentsReferences

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