Investigation of LiAlH 4-THF Formation by Direct Hydrogenation of Catalyzed Al and LiH

DSpace/Manakin Repository

Investigation of LiAlH 4-THF Formation by Direct Hydrogenation of Catalyzed Al and LiH

Show full item record

Title: Investigation of LiAlH 4-THF Formation by Direct Hydrogenation of Catalyzed Al and LiH
Author(s):
Lacina, D.;
Yang, L.;
Chopra, Irinder;
Muckerman, J.;
Chabal, Yves J.;
Graetz, J.
Format: text
Item Type: article
Keywords: Lithium
Hydrogenation
Abstract: The formation of LiAlH 4-THF by direct hydrogenation of Al and LiH in tetrahydrofuran (THF) was investigated using spectroscopic and computational methods. The molecular structures and free energies of the various possible adducts (THF-AlH 3, THF-LiH and THF-LiAlH 4) present in a LiAlH 4/THF solution were calculated and the dominant species were determined to be contact ion pairs where three THF molecules coordinate the lithium. Raman and X-ray absorption spectroscopy were used to investigate the effect of different Ti precursors on the formation of Al-H species and LiAlH 4-THF and determine the optimal reaction conditions. A unique sample stage was developed from a microfluidic cell to evaluate the catalysts in situ. The effectiveness of two types of catalysts, titanium chloride (TiCl 3) and titanium butoxide (Ti(C 4H 9O) 4), and the catalyst concentration were evaluated under similar reaction conditions. Both catalysts were effective at facilitating hydrogenation, although TiCl 3 was more effective over the first few cycles with the greatest kinetic enhancement achieved with a low concentration of around 0.15 mol%. These results were qualitatively supported by infrared spectroscopy, which indicated that although a small amount of Ti is necessary for disassociating H 2, excess surface Ti (>0.1 ML) hinders the formation of Al-H species. © the Owner Societies 2012.
ISSN: 1463-9076
Persistent Link: http://dx.doi.org/10.1039/c2cp40493a
http://hdl.handle.net/10735.1/2893
Terms of Use: © 2012 the Owner Societies

Files in this item

Files Size Format View
NSM-FR-Chabal-310536.03.pdf 1.789Mb PDF View/Open

This item appears in the following Collection(s)


Show full item record