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Howe, B. K. (1955) Interaction of 1:3-substituted propanols with inorganic non-metal halides. Doctoral thesis, Northern Polytechnic.
The behaviour of alcohols towards inorganic non-metal halides has been reviewed and the alcohols classified according to their reactivity in such systems.
Several propan-2-ols bearing substituents in the 1:3-positions have been synthesised and the effect of the substituents on the reactivity of the C-O-H group towards inorganic non-metal halides determined.
1:3-Diphenoxypropan-2-ol gave intractable esters but more satisfactory results were obtained with chloro-substituents. 1:3-Dichloropropan-2-ol was almost as reactive as an "ordinary” alcohol, such as n-butanol, but 1:1:3:3- tetrachloropropan-2-ol was considerably less reactive.
1:1:1:3:3:3-Hexachloropropan-2-cl proved to be an excellent example of the extreme case. Thus it did not react with phosphorue trichloride, phosphorus oxychloride, thionyl chloride, silicon tetrachloride or acetyl chloride, but reacted very slowly with phosphorus pentabromide, tribromide or oxybromide. In the presence of pyridine, there was formation of esters at -10 degrees. These results appear to be due to a drastic reduction in nucleophilic power of the hydroxyl-oxygen atom by the inductive offset of the substituent chlorine atoms, together with a reduction in the reactivity of the hydrogen atom by internal hydrogen bonding, both effects being compensated by hydrogen bonding with the base, ROH...NC5H5.
The ultra-violet end infra-red absorption spectra of these alcohols and the corresponding ketones afforded additional confirmation of the marked influence which adjacent chlorine-substituents have on the functional groups, C-O-H and C=0. Thus the C-H, C-OH, C=O stretching frequencies were modified in varying degrees according to the extent of substitution. Infra-red measurements on the chloro-alcohols in carbon tetrachloride solution provided information on the extent of association between the molecules.
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