Inadvertent synthesis of triacetone triperoxide (TATP)
May03

Inadvertent synthesis of triacetone triperoxide (TATP)

Via C&EN’s letters to the editor this week, some 1970s-era safety letters regarding inadvertent synthesis of triacetone triperoxide (TATP): Violent explosion (Feb. 21, 1977, page 5): While making 6-amino-penicillanic acid S-oxide, there was an explosion in our laboratory, at which time one man was injured. The cause of the accident has been found to be trimeric acetone peroxide. For the experiment in question we used 1 mole of 6-APA. It was oxidized according to the instructions published in “Synthesis” 1976, page 264, and precipitated as p-toluene sulfonate in the presence of acetone. 130 grams (0.32 mole) of the product was treated with triethylamine in isopropanol according to the instructions. The precipitate was filtered with suction on a glass sinter, washed with acetone, and air was allowed to flow through the filter cake. When the technician who was performing the experiment took the sinter in his hand and touched the precipitate with a steel spatula, it exploded violently. The technician received severe burns and splinter wounds in his eyes, hands, and body. Two windows were broken and there were holes in the glass of a fume cupboard at 3 m distance. The surface of the work table was spoiled. The explosive substance was found to be trimeric acetone peroxide. It was isolated from the mother liquor, from which it crystallized as large crystals. The melting point of the substance was 97° C. In literature [“Encyclopedia of Explosives and Related Items,” Vol. 1, Basil T. Fedoroff, Picatinny Arsenal, Dover, N.J. (1960)] the melting range is given at 94 to 98.5° C. The infrared spectrum was identified with the aid of a computer, and it was identical with the spectrum in the Sadtler catalog. On the basis of the NMR spectrum it was established to contain only one type of protons, τ = 8.5. The explosion of trimeric acetone peroxide was probably caused by the combined effect of static energy and friction. The static energy accumulated in man can be 30 mJ. We performed different sensitivity tests with the isolated substance. It exploded moist with an 11.5-mJ electric spark. In impact sensitivity tests, it ignited repeatedly with a weight of 2 kg from 10 cm’s height. In friction sensitivity tests, the sample ignited with a weight of 0.5 kg. The ignition sensitivity increased when the substance was dried. Trimeric acetone peroxide was the only explosive compound that we were able to isolate from the mother liquor that was spared. Thus we have every reason to believe that just this substance caused the accident. According to literature, acetone peroxide is easily produced from acetone and hydrogen peroxide catalyzed by an acid. A. Noponen...

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OPRD’s safety notables from the literature
Feb24

OPRD’s safety notables from the literature

Organic Process Research & Development has just released its 13th annual compilation of safety issues from scientific literature. It covers: Accidents Fire and Explosion Disasters in Aftermath of Great East Japan Earthquake Lab Explosion during Distillation of Propargyl Thiocyanate Lessons Learned from Process Safety Incidents Zinc Plant Explosion Methyl Mercaptan Accident Tianjin Blast Thermal Hazard Evaluations Decoupling Heat Absorption and Generation from Azobis(isobutyronitrile) Decomposition Ammonium Nitrate Thermal Decomposition with Additives Thermal Hazard Assessment for Synthesis of 3-Methylpyridine-N-oxide Analysis of Safety and Kinetic Parameters for Organic Peroxide Decomposition Prediction of Self-Accelerating Decomposition Temperature for Organic Peroxides Math Methods for Application of Experimental Adiabatic Data Vent Sizing of Cumene Hydroperoxide System under Fire Scenario Differential Scanning Calorimetry Analysis of Liquid Sodium-Silica Reaction Beyond the Phi Factor Thermal Stability of Propylene Oxide Hazard Assessment Methodology Systems Theoretic Accident Modeling and Processes (STAMP)—Holistic System Safety Approach or Another Risk Model? Decisions and Decision Support for Major Accident Prevention in Industry Process Safety Management for Managing Contractors in Process Plant Laboratory Safety Culture What Does “Safe” Look and Feel Like? Methods for Identifying Errors in Chemical Process Development and Design Methods and Models in Process Safety and Risk Management: Past, Present and Future Chemical Reactivity in PHA Scale-up and Scalable Reaction Conditions Application of Safety by Design Scale-up of Epoxide Ring-Opening Scale-up of Alkoxyamines Scale-up of Processes using DMSO Alternative Reagents Trifluoromethylation with Sodium Trifluoromethanesulfinate Iodonium Ylides as Safe Carbene Precursors Improved Method for Generation of Ohira–Bestmann Reagent Nonafluorobutanesulfonyl Azide as a Shelf Stable Oxidant Additional Trifluoromethylation with Sodium Trifluoromethanesulfinate Deoxyfluorination of Phenols with PhenoFluorMix New Reagent for Synthesis of CF3-Substituted Arenes and Heteroarenes A New Deoxyfluorination Reagent Dust Hazards Influence of Inert Materials on Flammable Dust Self-Ignition Hazard Evaluation Method for Dust Collector Explosions Dust Explosions in Process...

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Piranha solution explosions
Jan16

Piranha solution explosions

From the C&EN archives, but I believe still relevant today: April 23, 1990, page 2 SIR: We wish to report two violent explosions experienced with a sample of “piranha solution” used routinely in many laboratories to clean badly soiled glass frits and other surfaces. At Berkeley an explosion occurred in a bottle of this mixture that had been stored for several days. In this case, the solution was prepared by carefully mixing approximately 150 mL concentrated sulfuric acid with 150 mL 30% hydrogen peroxide with cooling over 30 minutes. No difficulty was experienced during the preparation, and no incidents were encountered after the preparation while the solution was allowed to stand (we believe only loosely capped) in a fume hood. However, one week after the solution was prepared it detonated spontaneously in the hood, destroying the glass container in which it was stored, as well as other bottles of chemicals stored in the hood. The other incident occurred several years ago at Cornell University. A graduate student was cleaning glass frits by a standard procedure of drawing small portions (about 20 mL) of a freshly prepared mixture of concentrated H2SO4 and 30% H2O2 through the frits by applying vacuum suction. This operation was eventually followed by washing with deionized water and finally acetone (keeping the different liquids separate). On this particular occasion, a violent explosion occurred, which shattered the heavy walled filter flask and caused multiple cuts in the face, chest, and forearms of the student. A partially lowered hood sash and appropriate clothing (safety glasses, lab coat, and heavy rubber gloves) provided some protection, but could not prevent the infliction of serious injuries. Subsequent questioning of the student led us to believe that inadvertent mixing of the highly oxidizing H2SO4/H2O2 mixture with an acetone residue (amounts unknown) was the cause of this accident. At Berkeley, it is possible that an oxidizable organic material was somehow added to the bottle in which the solution was stored, or that the top of the container was inadvertently tightened. However, to the best of our knowledge neither of these things occurred. Furthermore, the force of the detonation makes it seem likely to us that it was due to a chemical reaction rather than simply to the buildup of pressure in the container. In any case, we feel that the most prudent interpretation of these events is that sulfuric acid/hydrogen peroxide mixtures are susceptible to spontaneous and unpredictable chemical detonation. Warnings in the literature that these solutions be handled carefully should therefore be taken especially seriously. We recommend that this mixture not be stored for any length of time, and if possible not...

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Preparing piranha
Oct02

Preparing piranha

Piranha solutions are used to remove organic residues from substrates. Typically a 3:1 mixture of concentrated sulfuric acid to 30% hydrogen peroxide, it is highly corrosive and a powerful oxidizer. Simply mixing the solution is dangerous. And mixing piranha begs the question raises the question: Add the acid to the peroxide, or the other way around? Everyone hopefully learned in chemistry labs to “never cover an acid”–that is, when diluting, always add acid to water, not the other way around. For piranha, however, best practice is to add the peroxide to the acid. Robin Izzo, director of environmental health and safety at Princeton University, said this in an email to the ACS Division of Chemical Health & Safety e-mail list earlier this month: Around 20 years ago, I worked with two chemistry professors to develop best practices for handling piranha solutions. We tested different methods and found that (1) more often the mixture bubbled vigorously and created heat when adding the acid to the peroxide and (2) peroxide concentrations greater than 60% usually reacted violently, under 30% did not react violently and between 30 and 55% sometimes reacted violently. That was the reasoning behind keeping concentrations under 30% and not to exceed 50%. For reference, here is Princeton’s current guidance for making piranha. The University of Cambridge’s directions include a story of what can happen if you’re not careful when using piranha solutions. And the University of California, San Diego’s “A Day in the Lab” has a brief scene about making and using piranha solutions, starting at...

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Chemical safety tidbits and papers, from OPRD
Apr09

Chemical safety tidbits and papers, from OPRD

A tweet from Chemjobber that Organic Process Research & Development editor Trevor Laird is retiring at the end of the year made me realize that I forgot to highlight OPRD’s annual “Safety of Chemical Processes” section at the end of last year. Making up for the omission: Laird’s editorial: “There is a long way to go to educate and train to a high standard all chemists working in laboratories and chemical plants and to minimize the number of these incidents, which lead to damage to buildings and loss of profits, as well as loss of life. Companies always measure the cost of doing something (e.g., training) but never measure the cost of not doing something; there is a cost of not training staff, however, just as there is a cost associated with not complying with regulations (e.g., FDA regulations).” Safety Notables: Information from the Literature, including notes about Togni’s reagent, dimethylsulfoxide, hydroxylamine, peroxides, dimethyldioxirane, nitro-explosives, and safer reagents for a number of reactions Hydrazine and Aqueous Hydrazine Solutions: Evaluating Safety in Chemical Processes, from Lilly Research Laboratories Safer Preparation of m-CPBA/DMF Solution in Pilot Plant, from Suzhou Novartis Pharma Technology Process Safety Evaluation To Identify the Inherent Hazards of a Highly Exothermic Ritter Reaction Using Adiabatic and Isothermal Calorimeters, from Mylan Laboratories Safe Scale-Up of a Hydrazine Condensation by the Addition of a Base, from AbbVie Merck’s Reaction Review Policy: An Exercise in Process Safety, from...

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