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Rapid and One‐Step Transformation of LiAlH 4 to Inorganic and Organic Anion Intercalated Li‐Al Layered Double Hydroxides
Author(s) -
Pokhriyal Meenakshi,
Yadav Dileep Kumar,
Pal Sachin,
Uma Sitharaman,
Nagarajan Rajamani
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201900111
Subject(s) - chemistry , sebacic acid , powder diffraction , hydroxide , inorganic chemistry , infrared spectroscopy , monoclinic crystal system , crystallography , crystal structure , polymer chemistry , organic chemistry
Monoclinic [LiAl 2 (OH) 6 ]OH · 2H 2 O was formed by the hydrolysis of LiAlH 4 within few minutes of irradiation with microwaves as confirmed by powder X‐ray diffraction (PXRD), infrared, Raman, 27 Al NMR spectroscopic, and thermal analysis experiments. The flaky morphology of crystallites was evident in microscopy images. The compound is mesoporous with surface area of 50 m 2 /g. When required amounts of corresponding mineral acids were added during the hydrolysis of LiAlH 4 , exchange of the interlayer hydroxide ion with nitrate and chloride ions was successful. This was verified by the hexagonal symmetry observed in the PXRD patterns together with the evidence gathered from infrared, 27 Al NMR spectra, thermal analyses, and the substantial changes in ligand to metal charge‐transfer bands in their UV/Visible spectra. A host of Li‐Al LDH compounds intercalated with aliphatic dicarboxylate (oxalic, malonic, succinic, glutaric, adipic, and sebacic acid) anions were rapidly produced when a mixture of LiAlH 4 and the respective acid was irradiated with microwaves for a few minutes. The basal spacing of the dicarboxylate anion intercalated systems increased linearly with the increase in the number of –CH 2 ‐ groups in them. Microwave assisted reaction of ethylene glycol with [LiAl 2 (OH) 6 ]OH · 2H 2 O resulted in its intercalation.