Tatp Synthesis Essay

Via C&EN’s letters to the editor this week, some 1970s-era safety letters regarding inadvertent synthesis of triacetone triperoxide (TATP):

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
R&D Director, Fermion Oy, Tapiola, Finland

We are preparing R– and S-pentobarbital which requires the ozonolysis of R– and S-citronellic acids. Wolff-Kishner (Huang-Minion) reduction of the resulting citronellals yielded an unwanted product, melting point 95°, and with single proton peak on the NMR spectrum at 1.48δ. Gerald Lillquist of 3M Co. with the aid of a computer identified its infrared spectrum as that of trimeric acetone peroxide. By a rare coincidence, a few days later C&EN carried a report of a violent explosion in Finland caused by the identical compound (C&EN, Feb. 21, page 5).

In our experiment we ozonized citronellic acid (0.29 mole) dissolved in methylene chloride and immersed in a dry-ice acetone bath. Dimethyl sulfide (50 ml) was added to decompose the presumed ozonide. The mixture was allowed to come to room temperature, and it was then concentrated at reduced pressure. Hydrazine in glycol was added to the residue, followed by potassium hydroxide. The mixture was then heated to 200 °C. The triacetone peroxide distilled in respectable yield through a short, aircooled condenser between 105° and 135 °C. Hydrazine (and water) codistilled with the peroxide which thus remained as a suspension of large crystals. The suspension was disposed of by pouring it carefully into a large volume of cold, acidified aqueous solution of potassium iodide.

It is conceivable that during ozonolysis of any isopropylidene group triacetone peroxide is formed. Presumably it originates from the rearrangement of the (mol)ozonide. Consequently, appropriate care is advised.

Yul Yost
Minneapolis

You may well have heard about an incident at the University of Bristol, where a student inadvertently prepared some triacetone triperoxide (TATP). That’s a substance that I definitely won’t work with, but I haven’t done an entry on it in that category because of its unfortunate significance. No one is going to make a batch of FOOF at home, but TATP is another matter. It can be prepared from (reasonably) common chemicals, and thus is a favorite weapon of terrorist bombers the world over. Its main defect is its extreme sensitivity, which at least at one time earned it the nickname (in Arabic) of “Mother of Satan”. Here’s the Wikipedia page on acetone peroxides (there are several) if you want that on your browser history. Let there be no doubt: synthesizing and handling TATP in any sort of large quantity is an invitation to be killed without warning, and “large” kicks in quite early on the scale. High-energy compounds have no regard for the humans working with them; you’ll get more consideration from a hungry leopard, who at least might regard you as useful for his own ends.

When the Bristol story came out, it was hard to understand how someone wanders into making TATP, but this C&E News story has all the details. It was in the workup of a chlorite oxidation reaction done in acetone, and the original prep suggested adding a small amount of 30% hydrogen peroxide at the end to consume some yellow by-products (such as chlorine dioxide, which you’d rather not have around). The student tried it, and the yellow was still there, so he added some more. And some more, and some more. Without thinking, he got up to about 50 mL of peroxide, and on the workup, he noticed that he had a lot more organic phase material than he should have during the extraction. That, fortunately, was when the mental alarm went off – had he carried on and rota-vapped that stuff down, this story would doubtless have a much different ending. Theoretical yield was about 40g of TATP, which is too much by any reasonable person’s definition.

They called in the bomb squad, who did a controlled demolition, and that sounds like probably the right choice. If the TATP were diluted, it could probably be moved and then decomposed slowly, but the report is that the liquid was already becoming more viscous, so I can understand the caution. I wouldn’t volunteer to add the extra DI water to that sep funnel myself, much less any reducing agent. I’m very glad that no one was injured, and that this has perhaps called some attention (once again) to the fact that acetone and hydrogen peroxide do not live harmoniously.

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