The synthesis, characterization, and intercalation of n-alkyldiamines H2N(C
H2)(n)NH2 (n = 2, 3, 4, 6, 7, and 8) into layered hydrous tetratitanic acid
H2Ti4O9. nH(2)O are reported. From the elemental analysis, the following f
ormula were proposed for the intercalated compounds: (C2H8N2)(0.3)-H2Ti4O9.
0.40H(2)O, (C3H10N2)(0.6)H2Ti4O9.0.89H(2)O, (C4H12N2)(0.3)H2Ti4O9.0.40H(2)O
, (C6H16N2)(0.6)-H2Ti4O9.0.92H(2)O, (C7H18N2)(0.5)H2Ti4O9.0.50H(2)O and (C8
H20N2)(0.6)H2Ti4O9.0.60H(2)O. X-ray diffraction patterns for these matrices
showed that the 920 pm interlayer space of the original matrix has the d-s
pacing values increased to 1118, 1318, 1549, 1662, 1720, and 1766 pm, respe
ctively, for the C-2-C-8 sequence of intercalated n-alkyldiamine. The infra
red data are in agreement with the protonated nitrogen atoms of the diamine
s located in the cavity space. The hydrous matrix showed two mass loss step
s in the thermogravimetric curve, corresponding to the release of physisorb
ed and lattice water molecules. A third mass loss was observed for the inte
rcalated matrices due to the release of organic moiety. From these values,
the intercalated matrices represented by the number of carbons in the organ
ic chains can be ordered in the following sequence of thermal stability: C-
4 > C-2 > C-3 congruent to C-6 > C-7 congruent to C-8. The lowest amount of
intercalated n-alkyldiamines gave the largest thermal stability of the hyb
rid. (C) 2001 Elsevier Science Ltd. All rights reserved.