Ethers, aliphatic, tert alcohols

Aliphatic alcohols and benzyl alcohol are oxidized by Ph3Bi(OOtBu)2 to the corresponding carbonyl compounds (Equation (141)).233 It has been suggested that the oxidation occurs via dehydrogenation of alcohols by phenyl or tert-butoxy radical. When treated with diethyl ether, Ph3Bi(OOtBu)2 oxidizes the methyl group to afford ethoxyacetic... 

The classical method for making tert-butyl esters involves mineral acid-catalysed addition of the carboxylic acid to isobutene but it is a rather harsh procedure for use in any but the most insensitive of substrates [Scheme 6.33].80-82 Moreover, the method is hazardous because a sealed apparatus is needed to prevent evaporation of the volatile isobutene. A simpler procedure [Scheme 6.34] involves use of tert-butyl alcohol in the presence of a heterogeneous acid catalyst — concentrated sulfuric acid dispersed on powdered anhydrous magnesium sulfate. 3 No interna] pressure is developed during the reaction and the method is successful for various aromatic, aliphatic, olefinic, heteroaromatic, and protected amino acids. Also primary and secondary alcohols can be converted into the corresponding /erf-butyl ethers using essentially the same procedure (with the exception of alcohols particularly prone to carbonium ion formation (e.g. p-... 

If these parameters are used for the construction of a diagram as shown in Figure 5.1, a solvent selectivity triangle is obtained which clearly shows the differences between the individual solvents with regard to their dipolar (re ), acidic (a) and basic (/3) properties.2 The largest differences in the elution pattern can be expected if solvents are chosen which are as far apart from each other as possible. Because mixtures of two solvents, A and B, are used in most cases, only such solvents can be chosen which are miscible with each other. The usual A solvent in normal-phase separations is hexane, in reversed-phase separations it is water. Therefore the possible B solvents are limited in number. With regard to selectivity, it makes no real sense to try a normal-phase separation with diethyl ether as well as with tert, butyl methyl ether because all aliphatic ethers are located at the same spot in the selectivity triangle. Likewise it is not necessary to try several aliphatic alcohols for reversed-phase separations. 

Classification Tert. aliphatic alcohol Empirical CsHi20 Formula CH3CH2C(CH3)20H Properties Colorless clear volatile liq., char, camphoraceous odor, burning taste sol. in 8 parts water misc. with alcohol, ether, benzene, chloroform, glycerin, oils m.w. 88.15 sp.gr. 0.808 (20/4 C) vapor pressure 10 mm Hg (17.2 C) m.p. -9 C b.p. 100-103 C flash pt. (CC) 19 C ref. index 1.405... 

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