S-Butanol

Butanol, see sec-Butyl alcohol n-Butanol, see 1-Butanol n-Butan-l-ol, see 1-Butanol s-Butanol, see sec-Butyl alcohol sec-Butanol, see sec-Butyl alcohol f-Butanol, see ferf-Butyl alcohol ferf-Butanol, see ferf-Butyl alcohol Butan-l-ol, see 1-Butanol Butan-2-ol, see sec-Butyl alcohol... 

Starting with the optically active secondary alcohol sec-butanol (or butan-2-ol, but we want to emphasize that it is secondary), the secondary cation can be made by the usual method and has a characteristic 13C NMR shift. Quenching this cation with water regenerates the alcohol but without any optical activity. Water has attacked the two faces of the planar cation with exactly equal probability as we described in Chapter 16. The product is an exactly 50 50 mixture of (S)-butanol and (R)-butanol. It is racemic. 

The resolution of s-butanol is based on the different solubilities of the two diastereo-isomeric salts of the phthalate (10) with brucine. We are currently undertaking 2f-ray studies of these salts to determine the s-butyl environments with the ultimate purpose of designing better resolving agents. 

You saw in Chapter 19 that elimination reactions can be used to make alkenes from alcohols using acid or from alkyl halides using base. The acid-catalysed dehydration of tertiary butanol works well because the double bond has no choice about where to form. But the same reaction on s-butanol is quite unselective—as you would expect, the more substituted alkene is formed (almost solely, as it happens) but even then it s a mixture of geometrical isomers. 

For all compounds except isobutanol (5), the data compilation of Yaws and co-workers (44,45) was selected for enthalpy of formation of ideal gas. For isobutanol, the variation of values with temperature was estimated from the temperature behavior of values for t-butanol and s-butanol. Data for enthalpy of formation of the ideal gas is a series expansion in temperature, Equation (1-11). Results from the correlation are in favorable agreement with data. 

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