Kink Block Structures in Clay Organic Complexes

G. Lagaly*, St. Fitz and Armin Weiss
Institut für Anorganische Chemie der Universität Kiel
Institut für Anorganische Chemie der Universität München, GFR
*Correspondence and requests for reprints to G. Lagaly.

Abstract: Complexes of n-tetradecylammonium-beidellite with n-alkanols (n-C14H29NH3+)0,44(n-CxH2x + 1OH) 1,56{Mg0,28Al1,81(OH)2Si3,56Al0,44O10}0,44− (x = 8‒22) have been prepared and characterized by their basal spacings and by measurements of the specific heat cp.

The compounds undergo a series of reversible phase transitions β1 ⇌ ... ⇌ βi ⇌ ... ⇌ βω ⇌ χ1 ⇌ ... ⇌ χj with rising temperature. The maximum number ω of β-phases depends upon the chain lengths and increases from 1 with decanol to 6 with docosanol. Due to the evaporation of alkanol the number of χ-phases is not yet established in all details.

The β-transitions correspond to conformational changes of the alkyl chains via rotational isomerisation, especially kink formation. The β-phases become unstable if the kink concentration exceeds 0,14 kinks/-CH2-. The β/χ-transition is probably caused by a rearrangement into special gauche-block structures.

Clays and Clay Minerals; March 1975 v. 23; no. 1; p. 45-54; DOI: 10.1346/CCMN.1975.0230107
© 1975, The Clay Minerals Society
Clay Minerals Society (www.clays.org)