Molecular association in pairs of long-chain compounds. IV. Influence of cation and the hydroxyl position on the alkyl sulfate, alkyl alcohol association

The interaction of Li⁺, K⁺, NH₄⁺, Mg⁺⁺, Ca⁺⁺, and tetramethyl ammonium (TMA⁺) lauryl sulfates with lauryl alcohol has been examined by differential thermal analysis, infrared, and x-ray methods. Evidence is obtained that the first four of these long-chain salts form intermolecular complexes with lauryl alcohol in which the stoichiometry is 1:1, i.e., one long chain of the sulfate to one of alcohol. The Ca⁺⁺ and TMA⁺ salts do not form such complexes. The formation of a (1:2) complex of sodium lauryl or myristyl sulfate and tetradecanol is inhibited if the hydroxyl group is changed from the 1 to the 2 position. The enthalpies of formation of the complexes are estimated and have the order Na⁺ > Mg⁺⁺ > NH₄⁺ > K⁺ > Li⁺.