Ethers explosive potential

Most ethers are potentially ha2ardous chemicals because, in the presence of atmospheric oxygen, a radical-chain process can occur, resulting in the formation of peroxides that are unstable, explosion-prone compounds (7). The reaction maybe generalized in terms of the following steps involving initiation, propagation, and termination. 

Methyl trifluorovinyl ether, b.p. 10.5- 12.5°C, prepared from tetrafluoroethylene and sodium methoxide [1], has considerable explosive potential. On ignition, it decomposes more violently than acetylene and should be treated with extreme caution [2], Other trifluorovinyl ethers are similarly available from higher alkoxides [1], and although not tested for instability, should be handled carefully. Presence of fluoro-haloalkanes boiling lower than the ether stabilises the latter against spark-initiated decomposition in both fluid phases [3],... 

Diethyl ether—often called ethyl ether or just ether —was used as a general anesthetic as early as 1842. Administered as a vapor, it acts as a depressant on the central nervous system, causing unconsciousness. However, its high flammability and volatility present hazards in the operating room. Ethers such as ethyl vinyl ether, divinyl ether, and methyl propyl ether have also seen use as anesthetics. All the low molecular weight ethers are potentially explosive when mixed with oxygen. 

It is not advisable to store large quantities of picrates for long periods, particularly when they are dry due to their potential EXPLOSIVE nature. The free base should be recovered as soon as possible. The picrate is suspended in an excess of 2N aqueous NaOH and warmed a little. Because of the limited solubility of sodium picrate, excess hot water must be added. Alternatively, because of the greater solubility of lithium picrate, aqueous 10% lithium hydroxide solution can be used. The solution is cooled, the amine is extracted with a suitable solvent such as diethyl ether or toluene, washed with 5N NaOH until the alkaline solution remains colourless, then with water, and the extract is dried with anhydrous sodium carbonate. The solvent is distilled off and the amine is fractionally distilled (under reduced pressure if necessary) or recrystallised. 

The aryldiazosulphide ArN=NSPh (1.3 mmol) in DMSO (50 ml) is stirred under Ar with TBA-CN (1.75 g, 6.5 mmol) in DMSO (50 ml) and the solution is irradiated with tungsten light until the evolution of N2 ceases. Brine (150 ml) is added and the mixture is extracted with EtzO (4 x 50 ml). The ethereal extracts are washed with aqueous NaOH (10%, 50 ml) and brine (50 ml), dried (Na2S04), and evaporated to yield the benzonitrile (30-70%). The diazosulphides are potentially EXPLOSIVE. 

The drying of impure ethers presents a potential explosion hazard. Those unfamiliar with this hazard should consult Inorganic Syntheses, Vol. 12, p. 317, 1970. 

The development of plastics accompanied synthetic fibers. The first synthetic plastic with the trade name Celluloid was made in 1870 from a form of nitrocellulose called pyroxylin, the same substance used to produce the first rayon. Celluloid was developed in part to meet the demand for expensive billiard balls, which at the end of the nineteenth century were produced from ivory obtained from elephant tusks. John Wesley Hyatt (1837-1920) combined pyroxylin with ether and alcohol to produce a hard substance called collodion. Hyatt s collodion, like Bernigaut s original rayon, was unstable and potentially explosive. He solved this problem by adding camphor to the collodion to produce a stable hard plastic he called Celluloid. 

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