Bottle of Isopropyl Ether

A chemist needed isopropyl ether. He found a pint glass bottle. He unsuccessfully tried to open the bottle over a sink. The cap appeared to be stuck tightly, so he grasped the bottle in one hand, pressed it to his stomach and twisted the cap with his other hand. Just as the cap broke loose, the bottle exploded, practically disemboweling the man and tearing off several fingers. The victim remained conscious and, in fact, coherently described how the accident happened. The man was taken to a hospital and died within 2 hr of the accident of massive internal hemorrhage. 

An accident investigation identified the cause of the accident to be the rapid decomposition of peroxides, which formed in the ether while the bottle sat in storage. It is hypothesized that some of the peroxides crystallized in the threads of the cap and exploded when the cap was turned. 

As ethers age, especially isopropyl ether, they form peroxides. The peroxides react further to form additional hazardous by-products, such as triacetone peroxide. These materials are unstable. Light, air, and heat accelerate the formation of peroxides. 

Ethers should be stored in metal containers. Only small quantities should be purchased. Ethers should not be kept over 6 months. Containers should be labeled and dated upon receipt, and opened containers should be discarded after 3 months. All work with ethers should be done behind safety shields. Inhibitors should be used whenever possible. 

The investigation indicated that the vessel contents were held for 11 hr. A steam leak into the jacket brought the temperature to about 150°C. Although previous tests indicated decomposition at 200°C, subsequent tests showed exothermic decomposition above 145°C. 

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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. 

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. 

FIGURE 5.3.2.4 Dangerous peroxide crystals found in bottle of isopropyl ether. Never touch a bottle that has potential peroxide crystals - they are very sensitive and can explode. They should he removed by the bomh squad. (Courtesy of Thomas Gundlach.)... 

Filtered isopropyl alcohol shall be used for rinsing the sample bottle and filter holder instead of petroleum ether specified in Method 2276-65T... 

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. 

The commercial product usually contains appreciable quantities of peroxide this should be removed by treatment with an acidified solution of an iron(n) salt or with a solution of sodium sulphite (see under 15. Diethyl ether). The diisopropyl ether is then dried over anhydrous calcium chloride and distilled, the fraction b.p. 68.5 °C/760 mmHg being collected. Di-isopropyl ether should be stored in brown bottles away from the light. A small amount of hydroquinone (2 x 10 5 m) may be added as a peroxide inhibitor. 

The a-position of an ether is susceptible to attack by free radicals and, in certain circumstances, by halogens. Ethers are slowly oxidized by the oxygen from air to form peroxides- This can be a hazard in stored bottles of ethers, particularly with the higher ethers such as di-isopropyl ether. These peroxides may be destroyed by treatment with iron(IT) sulfate. Chlorine reacts with ethers, particularly in sunlight. These a-halo ethers then decompose to the aldehyde and an alcohol. 

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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