Diethyl ether, decomposition

Path b, a four-center elimination process, reported in the diethyl ether decomposition , is a very dubious reaction, viz. 

Tribromoacetic acid [75-96-7] (Br CCOOH), mol wt 296.74, C2HBr302, mp 135°C bp 245°C (decomposition), is soluble in water, ethyl alcohol, and diethyl ether. This acid is relatively unstable to hydrolytic conditions and can be decomposed to bromoform in boiling water. Tribromoacetic acid can be prepared by the oxidation of bromal [115-17-3] or perbromoethene [79-28-7] with fuming nitric acid and by treating an aqueous solution of malonic acid with bromine. 

Cyclizine Hydrochloride. l-(Diphenylmethyl)-4-methylpipera2ine monohydrochloride [303-25-3] (Mare2ine) (17) is a white crystalline powder, or small colorless crystals, that is odorless or nearly so and has a bitter taste. It melts indistinctly and with decomposition at ca 285°C. One gram of cycli2ine hydrochloride [303-25-3] is soluble in 115 mL water, 115 mL ethanol, and 5 mL chloroform it is insoluble in diethyl ether. It may be made by the synthesis shown in Reference 15. 

Dinitrochlorobenzene. This compound is a yeUow soHd that can exist in three forms, one stable and two labile. The stable a-form crystallizes in yeUow rhombic crystals from diethyl ether mp a is 53.4°C, P 43°C, and y 27°C bp at 101 kPa (= 1 atm) 315°C with slight decomposition ... 

A (4-Hydroxyphenyl)glycine. This derivative (23) forms aggregate spheres or shiny leaflets from water. It turns brown at 200°C, begins to melt at 220°C, and melts completely with decomposition at 245 —247°C. The compound is soluble in alkaU and mineral acid and sparingly soluble in water, glacial acetic acid, ethyl acetate, ethanol, diethyl ether, acetone, chloroform, and benzene. 

Pyrrole is soluble in alcohol, benzene, and diethyl ether, but is only sparingly soluble in water and in aqueous alkaUes. It dissolves with decomposition in dilute acids. Pyrroles with substituents in the -position are usually less soluble in polar solvents than the corresponding a-substituted pyrroles. Pyrroles that have no substituent on nitrogen readily lose a proton to form the resonance-stabilized pyrrolyl anion, and alkaU metals react with it in hquid ammonia to form salts. However, pyrrole pK = ca 17.5) is a weaker acid than methanol (11). The acidity of the pyrrole hydrogen is gready increased by electron-withdrawing groups, eg, the pK of 2,5-dinitropyrrole [32602-96-3] is 3.6 (12,13). 

Ethyl chloride can be dehydrochlorinated to ethylene using alcohoHc potash. Condensation of alcohol with ethyl chloride in this reaction also produces some diethyl ether. Heating to 625°C and subsequent contact with calcium oxide and water at 400—450°C gives ethyl alcohol as the chief product of decomposition. Ethyl chloride yields butane, ethylene, water, and a soHd of unknown composition when heated with metallic magnesium for about six hours in a sealed tube. Ethyl chloride forms regular crystals of a hydrate with water at 0°C (5). Dry ethyl chloride can be used in contact with most common metals in the absence of air up to 200°C. Its oxidation and hydrolysis are slow at ordinary temperatures. Ethyl chloride yields ethyl alcohol, acetaldehyde, and some ethylene in the presence of steam with various catalysts, eg, titanium dioxide and barium chloride. 

S4N2 forms dark red needles (mp 23°C) upon recrystallization from diethyl ether. It sublimes readily at room temperature, but must be stored at -20°C to avoid decomposition. Several routes are available for the preparation of S4N2. The decomposition of Hg(S7N)2 at room temperature gives the best yield, while the reaction of S2CI2 with aqueous ammonia is quick, cheap and provides a purer product. 

Arsine, AsHs, is formed when many As-containing compounds are reduced with nascent hydrogen and its decomposition on a heated glass surface to form a metallic mirror formed the basis of Marsh s test for the element. The low-temperature reduction of AsCls with LiAlH4 in diethyl ether solution gives good yields of the gas as does the dilute acid hydrolysis of many arsenides of electropositive elements (Na, Mg, Zn, etc.). Similar reactions yield stibine, e.g. ... 

The effect of dinitrogen pentoxide in a dichloromethane solution on diethyl ether at a temperature lower than 20°C caused a detonation. It was explained by the decomposition of nitroglycol formed as follows ... 

The stannic chloride complex is decomposed relatively slowly. Addition of 5-10 ml. of diethyl ether facilitates the decomposition. If the decomposition is not completed during the heating period, the wash with water gives a troublesome precipitation of stannic hydroxide. If this occurs the organic phase should either be heated for 30 minutes with, or allowed to stand overnight with, 100 ml. of 6 A hydrochloric acid. 

An example of a catalytic gas-phase reaction is the decomposition of diethyl ether catalyzed by iodine (I,) ... 

Compound 51 was found to be unstable and difficult to purify, as described in the literature [93—95]. Therefore, 51 was not isolated, but was instead converted to the stable pinacol 1-acetamido-l-hexylboronate derivative 52. However, the acylated derivative 52 could not be purified by column chromatography as it was destroyed on silica gel and partially decomposed on alumina. Fortunately, we found that it dissolves in basic aqueous solution (pH > 11) and can then be extracted into diethyl ether when the pH of the aqueous layer is 5—6. Finally, pure 52 was obtained by repeated washing with weak acids and bases. It should be mentioned here that exposure to a strongly acidic solution, which also dissolves compound 51, results in its decomposition. Compared with other routes, the present two-step method involves mild reaction conditions (THF, ambient temperature) and a simple work-up procedure. It should prove very useful in providing an alternative access to a-aminoboronic esters, an important class of inhibitors of serine proteases. 

Thermal decomposition of diethyl ether is postulated by Hinshelwood (Kinetics of Chemical Change, 1941) to proceed by the chain mechanism. 

Many incidents involving explosions have been attributed, not always correctly, to peroxide formation and violent decomposition. Individually indexed incidents are 2-Acetyl-3-methyl-4,5-dihydrothiophen-4-one, 2807 Aluminium dichloride hydride diethyl etherate, Dibenzyl ether, 0061 f 1,3-Butadiene, 1480 f Diallyl ether, 2431 f Diisopropyl ether, 2542... 

The purpose of the wash with diethyl ether and isopropyl alcohol is to remove the remaining acetic acid and any residual hydrogen chloride, which may cause decomposition during the subsequent crystallization. 

In comparison to other vinylic compounds , the vinyl proton in 1-alkenyl carbamates, deprotonation has a very high kinetic acidity . After protection of the 4-hydroxy group in the homoaldol products by silylation, deprotonation (w-BuLi, TMEDA, diethyl ether or THF) of enol carbamate 384 is complete at —78 °C (equation 103), and the resulting vinyUithium 385 can be kept at this temperature without decomposition for several hours. Stannylation , silylation , methoxycarbonylation (with methyl chloroformate) ... 

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