Isopropyl ether explosion

The nature of the initiation step, which may occur in a variety of ways, is not known in all cases. Commonly used ethers such as ethyl ether, isopropyl ether, tetrahydrofuran, and i)-dioxane are particulady prone to form explosive peroxides on prolonged storage and exposure to air and light (see Peroxides AND PEROXY COMPOUNDS, ORGANIC), and should contain antioxidants (qv) to prevent their build-up. One of the exceptions to the peroxide forming tendency of ethers is methyl fert-alkyl ethers such as methyl fert-butyl ether [1634-04-4] (MTBE) and fert-amyl methyl ether [994-05-8] (TAME). Both have shown htde tendency if any to form peroxides (2,8). 

Illustrate the layered accident investigation process, using Example 13-1 as a guide, to develop the underlying causes of the duct system explosion described in section 13-1. 13-2. Repeat Problem 13-1 for the bottle of isopropyl ether accident described in section 13-2. 13-3. Repeat Problem 13-1 for the nitrobenzene sulfonic acid decomposition accident described in section 13-2. 

Some chemicals are susceptible to peroxide formation in the presence of air [10, 56]. Table 2.15 shows a list of structures that can form peroxides. The peroxide formation is normally a slow process. However, highly unstable peroxide products can be formed which can cause an explosion. Some of the chemicals whose structures are shown form explosive peroxides even without a significant concentration (e.g., isopropyl ether, divinyl acetylene, vinylidene chloride, potassium metal, sodium amide). Other substances form a hazardous peroxide on concentration, such as diethyl ether, tetrahydrofuran, and vinyl ethers, or on initiation of a polymerization (e.g., methyl acrylate and styrene) [66]. 

Isopropyl ether readily forms explosive peroxides. It should be tested for peroxides, and contact with air should be minimized. 

Peroxides in ether solvents. This is one of the commonest causes of explosions in organic chemistry laboratories. Simple dialkyl ethers such as diethyl ether and di-isopropyl ether, and cyclic ethers such as 1,4-dioxane and tetrahydrofuran, form less volatile peroxides on exposure to air and light. If therefore one of these solvents is purified by distillation, the peroxide content in the residue is progressively increased and eventually a violent explosion may occur. In view of this (i) such solvents should not be stored for long periods or in half empty bottles containers should be of dark glass (ii) before the solvents are distilled a peroxide test should be carried out, and, if positive, the peroxide must be removed (Section 4.1.11, p. 402 and Section 4.1.75, p. 404) and (iii) since purified ethers in contact with air rapidly peroxidise again (10 minutes in the case of tetrahydrofuran) they should be retested for peroxides and purified if necessary immediately before use. 

Compared to other classes of organic compounds, ethers have relatively low toxicities. This characteristic can be attributed to the low reactivity of the C-O-C functional group arising from the high strength of the carbon-oxygen bond. Like diethyl ether, several of the more volatile ethers affect the central nervous system. Hazards other than their toxicities tend to be relatively more important for ethers. These hazards are flammability and formation of explosive peroxides (especially with di-isopropyl ether). 

ISOPROPYL ETHER (108-20-3) C H,40 Forms explosive mixture with air extremely low ignition temperature makes it very dangerous (flash point -18°F/-28°C Fire Rating 3). Exceptionally vulnerable to the formation of unstable peroxides that precipitate as dry crystalline material and... 

ETHYLENE GLYCOL ISOPROPYL ETHER (109-59-1) Forms explosive mixture with air (flash point 92°F/33°C). Violent reaction with strong oxidizers. Incompatible with aliphatic amines, caustics, isocyanates, nitric acid, perchloric acid, sulfuric acid. 

Most ethers, when stored for more than six months, will form explosive ether peroxides in their containers. The primary ethers to be concerned about are ethyl ether, ethyl tertiary butyl ether, ethyl tertiary amyl ether, and isopropyl ether. Isopropyl ether is considered the worst hazard in storage. 

Isopropyl ether forms explosive mixtures with air the LEE and UEL values are 1.4% and 7.9% by volume in air, respectively. It forms unstable peroxides on long standing or in contact with air. These peroxides may explode on mechanical shock or on heating. Peroxides can be destroyed with sodium sulfite or acidified ferrous sulfate solutions. 

Isopropyl ether (diisopropyl ether [CAS 108-20-3]) A skin irritant upon prolonged contact ith liquid. Vapors mildly irritating to the eyes and respiratoiy tract. A CNS depressant. 250 ppm 1400 ppm [LEL] 1 3 1 Coloriess liquid. Oifensive and sharp ether-like odor and Irritation are good warning properties. Vapor pressure is 119 mm Hg at 20°C (68°F). Highly flammable. Contact with air causes fomnadon of explosive peroxides. 

Isopropyl ether seems unusually susceptible to peroxidation and there are reports that a half-filled 500-ml bottle of isopropyl ether peroxidized despite being kept over a wad of iron wool. Although it may be possible to stabilize isopropyl ether in other ways, the absence of a stabilizer may not always be obvious from the appearance of a sample, so that even opening a container of isopropyl of uncertain vintage to test for peroxides can be hazardous. Noller comments that neither hydrogen peroxide, hydroperoxide nor the hydroxy alkyl peroxide are as violently explosive as the peroxidic residues from oxidized ether. ... 

A student working in a laboratory needed a chemical for an experiment. While looking for this chemical he came across a bottle of isopropyl ether. He remembered that isopropyl ether was well known for explosions from peroxide formations. As he looked at it, it appeared to be filled with large crystals and he knew that it should be a liquid, not a solid. He reported this to his professor who came to look at the bottle too. The professor ordered everyone out of the stockroom and called local emergency response officials who sent out the bomb squad. The bomb squad removed the bottle for controlled detonation in an open field. 

A chemist had worked in a laboratory at a company for three years. He had inherited chemicals from a predecessor. He needed some isopropyl ether for an experiment and found a pint bottle on the shelf. He took it to a sink where he tried to open the bottle. The cap was difficult to open so he held it close to his body to get a better grip on the top, and twisted the cap loose. As the cap came loose, the bottle exploded. The chemist suffered devastating wounds to his abdominal area and lost several fingers in the explosion. Although a nearby colleague reached him quickly and got medical care for him, the chemist died at the hospital of internal injuries. 

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