Etude approfondie de la contraction dans les melanges alcools-eau, Partie 3: Nouveaux resultats sur la contraction dans les melanges methanol, 1- et 2-propanol et tert-butanol avec eau; sa determination, representation et signification liee a des associa

摘要

The volume contraction in mixtures of the monohydroxy alcohols, methanol, 1- and 2-propanol and tert-butanol with water were determined applying similar methods of calculation as those used in our previous work on ethanol-water mixtures. Each of the curves obtained for these mixtures, which represent the contraction as a function of %vol, %mas and %mol, are characteristic in form and inten- sity. Proceeding from methanol, to 1- and 2-propanol and to tert-butanol, curves are observed with maximum contractions positioned between 12 to 40%mol, 34 to 55%mas and 42 to 62%vol respectively. The maximum degree of contraction also varies with the type of alcohol and the temperature. Whereas for methanol-water the variation in contraction with temperature is hardly noticeable, this variation is much stronger in the other alcohol-water mixtures. The contraction maximum as a function of %mol also provides strong indications as to the nature of the associations between the alcohol and water molecules. With the help of Jobs method the most probable alcohol-water molecular ratios could be identified: A_2W_3 for methanol, A_1W_5 for 2-propanol, A_1W_6 for 1-propanol and A_1W_7 for tert-butanol. As associations of the "cluster type" are visibly present in these mixtures more complex aggregates of the type (A_iW_j)p are also possible.