(Solid + liquid) phase equilibria and solid-solvate formation in tetrahydrofuran + (lithium or sodium) tetrahydridoaluminate

Abstract

The (solid+liquid) phase diagrams have been obtained from d.s.c. curves for x = 0 to 0.38 and for x = 0 to 1 respectively for {(1 − x)c−(CH2)4O + xLiAlH4} and {(1 − xc−(CH2)4O + xNaAlH4}. In the first, four compounds LiAlH4 · n{c−OCH2)4O} have been found: n = 2 decomposing at 255.8 K, a solid solution near n = 3 melting congruently at 304 K, n = 4 melting incongruently at 235.6 K, and n = 6 melting incongruently or decomposing at 236 K. The existence of two compounds NaAlH4 · n{c−(CH2)4} has been established in the second: n = 4 and n = 6 melting incongruently at 232.1 K and 246.2 K respectively. The existence of each compound has been established by means of a Tamman diagram along each invariant line.