Diethyl ether, vaporization

Consider Tables 22.1 and 22.2. A crystal of sodium chloride, NaCl, is exposed to an air sample that has water vapors, ethanol vapors, and diethyl ether vapors. (Water, ethanol, and diethyl ether are all liquids at room temperature.) Ignoring the possibility of minimum-energy interactions between the three vapors (that is, azeotropes and the like), what would you predict to be the true surface structure of NaCl (Ignore interactions between the NaCl and the vapors.)... 

To a stirred solution of phenylacetylene (44 mg, 0.43 mmol) in methanol was added sodium hydroxide (23 mg, 0.58 mmol). The resultant solution was stirred at room temperature for 30 min. [Pt(trpy)(MeCN)](OTf)2 (300 mg, 0.39 mmol) was added to the reaction mixture, which turned to a deep red solution immediately and was then stirred for 12 h at room temperature. The mixture was filtered, and a saturated solution of ammonium hexafluorophosphate in methanol was added. The product was isolated, washed with methanol, and dried. Subsequent recrystallization by diffusion of diethyl ether vapor into an acetonitrile solution of the product gave [Pt(trpy)C=C-Ph]PF6 as dark purple crystals. Yield 174 mg, 60%. 

Ethers are relatively uncommon atmospheric pollutants, although the flammability hazard of diethyl ether vapor in an enclosed work space is well known. In addition to aliphatic ethers, such as dimethyl ether and diethyl ether, several alkenyl ethers, including vinylethyl ether, are produced by internal combustion engines. Methyltertiarybutyl ether, MTBE, became tiie octane booster of choice to replace tetraethyllead in gasoline. Because of its widespread distribution, MTBE has the potential to be an air pollutant, although its hazard is limited by its low vapor pressure. Largely because of its potential to contaminate water, MTBE was proposed for phaseout by both the state of California and the U.S. Environmental Protection Agency in 1999. Ethers are relatively unreactive and not as water-soluble as the lower alcohols or carboxylic acids. 

Anionic polymerization of vinyl monomers can be effected with a variety of organometaUic compounds alkyllithium compounds are the most useful class (1,33—35). A variety of simple alkyllithium compounds are available commercially. Most simple alkyllithium compounds are soluble in hydrocarbon solvents such as hexane and cyclohexane and they can be prepared by reaction of the corresponding alkyl chlorides with lithium metal. Methyllithium [917-54-4] and phenyllithium [591-51-5] are available in diethyl ether and cyclohexane—ether solutions, respectively, because they are not soluble in hydrocarbon solvents vinyllithium [917-57-7] and allyllithium [3052-45-7] are also insoluble in hydrocarbon solutions and can only be prepared in ether solutions (38,39). Hydrocarbon-soluble alkyllithium initiators are used directiy to initiate polymerization of styrene and diene monomers quantitatively one unique aspect of hthium-based initiators in hydrocarbon solution is that elastomeric polydienes with high 1,4-microstmcture are obtained (1,24,33—37). Certain alkyllithium compounds can be purified by recrystallization (ethyllithium), sublimation (ethyllithium, /-butyUithium [594-19-4] isopropyllithium [2417-93-8] or distillation (j -butyUithium) (40,41). Unfortunately, / -butyUithium is noncrystaUine and too high boiling to be purified by distiUation (38). Since methyllithium and phenyllithium are crystalline soUds which are insoluble in hydrocarbon solution, they can be precipitated into these solutions and then redissolved in appropriate polar solvents (42,43). OrganometaUic compounds of other alkaU metals are insoluble in hydrocarbon solution and possess negligible vapor pressures as expected for salt-like compounds. 

Carbon tetrachloride is toxic by inhalation of its vapor and oral intake of the Hquid. Inhalation of the vapor constitutes the principal ha2ard. Exposure to excessive levels of vapor is characterized by two types of response an anesthetic effect similar to that caused by compounds such as diethyl ether and chloroform and organic injury to the tissues of certain organs, in particular the Hver and kidneys. This type of injury may not become evident until 1—10 days after exposure. The nature of the effect is deterrnined largely by the vapor concentration but the extent or severity of the effect is deterrnined principaHy by the duration of exposure (38). 

Manufacture. Much of the diethyl ether manufactured is obtained as a by-product when ethanol (qv) is produced by the vapor-phase hydration of ethylene (qv) over a supported phosphoric acid catalyst. Such a process has the flexibiHty to adjust to some extent the relative amounts of ethanol and diethyl ether produced in order to meet existing market demands. Diethyl ether can be prepared directly to greater than 95% yield by the vapor-phase dehydration of ethanol in a fixed-bed reactor using an alumina catalyst (21). 

Since a vapor pressure of 200 niin Hg is eoiisiderable, the chance of as little as 7.3% of the diethyl ether evaporating to reach the LFL is quite liigh. Those periods of time, such as weekends, when the refrigerator might not be opened, would result in situations of greatest risk. 

Methylfuran, irradiated in the presence of mercury vapor, gave carbon monoxide and a fraction containing 1,3-butadiene and 3-methylcyclopropene (45 55) (67JA1758). Subsequently, it was found that in both sensitized and direct photolysis of 2-methylfuran a more complex mixture of products was obtained, where 3-methylfuran was present (Scheme 5) (68JA2720 70JPC574). 3-Methylfuran was the only product when 2-methylfuran was irradiated in diethyl ether (68JA2720). 

Consider the following data for the vapor pressure of diethyl ether, a widely used anesthetic in the early days of surgery. 

Follow the instructions in Question 13 to estimate the heat of vaporization of diethyl ether. 

The only ether that you are likely to encounter in the laboratory is diethyl ether, often referred to simply as ether. It was first used as an anesthetic in the 1840s. Today we use other compounds for that purpose, for at least a couple of reasons. For one thing ether vapor is... 

Self-Tfst 7.7B Use Trouton s rule to estimate the standard enthalpy of vaporization of diethyl ether, C4H1()0, which boils at 34.5°C. 

Consider an apparatus in which A and B are two 1.00-L flasks joined by a stopcock C. The volume of the stopcock is negligible. Initially, A and B are evacuated, the stopcock C is closed, and 1.50 g of diethyl ether, C2HsOC2H5, is introduced into flask A. The vapor pressure of diethyl ether is 57 Torr at —45°C, 185 Torr at 0.°C, 534 Torr at 25°C, and negligible below — 86°C. (a) If the stopcock is left closed and the flask is brought to equilibrium at —45°C, what will be the pressure of diethyl ether in flask A (b) If the temperature is raised to 25°C, what will be the pressure of diethyl ether in the flask (c) If the temperature of the assembly is returned... 

Site-selection spectroscopy Maximum selectivity in frozen solutions or vapor-deposited matrices is achieved by using exciting light whose bandwidth (0.01-0.1 cm-1) is less than that of the inhomogeneously broadened absorption band. Lasers are optimal in this respect. The spectral bandwidths can then be minimized by selective excitation only of those fluorophores that are located in very similar matrix sites. The temperature should be very low (5 K or less). The techniques based on this principle are called in the literature site-selection spectroscopy, fluorescence line narrowing or energy-selection spectroscopy. The solvent (3-methylpentane, ethanol-methanol mixtures, EPA (mixture of ethanol, isopentane and diethyl ether)) should form a clear glass in order to avoid distortion of the spectrum by scatter from cracks. 

Fuangfoo, S., Kersting, M., and Viswanath, D.S. Isothermal vapor-liquid equilibria for methyl-2,2-dimethylethyl ether + 2-methylpropan-2-ol, diethyl ether -t ethyl-2,2-dimethylethyl ether. 2-methyl-2-buteue+ (2-methylbutan-2-ol), and diisopropyl ether -t octane, J. Chem. Eng. Data, 44(3) 405-410, 1999. 

The state of aggregation of RLi in various solvents has been investigated by a variety of methods. In 1967, West and Waack used a differential vapor pressure technique to study solution colligative properties of RLi . Deviations from ideality indicated that in THF at 25 °C, MeLi and BuLi are tetrameric, PhLi dimeric and benzyllithium monomeric. MeLi was also suggested to be tetrameric in diethyl ether. 

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