Alanates

The sodium alanate hydride NaAlH4 is so far the most investigated and promising hydrogen storage material, at least on a short time scale (for reviews see [1-7]). 

According to the literature the thermal decomposition of NaAlH4 occurs in a three-step reaction  

In further developments Sandrock et al. [1, 75] optimized the amount of Ti catalyst needed to effectively increase the rates of absorption/desorption and introduced 

Fichtner et al. [77, 78] added small Ti clusters (Ti13 6THF the synthesis of these clusters is described in [77]) to highly purified NaAlH4 by ball milling for 30 min and observed a substantial improvement of desorption/absorption kinetics for an alanate doped with 2 mol% of Ti clusters. A doped alanate desorbed on 

In summary, one can say that NaAlH4 is one of the most extensively researched hydride. Although the desorption/absorption temperatures and time durations for a 

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Moser J 1976 Periodic orbits near an equilibrium and a theorem by Alan Weinstein Comm. Pure Appl. Math. 29 727... 

Diflfiisive processes nonnally operate in chemical systems so as to disperse concentration gradients. In a paper in 1952, the mathematician Alan Turing produced a remarkable prediction [37] that if selective diffiision were coupled with chemical feedback, the opposite situation may arise, with a spontaneous development of sustained spatial distributions of species concentrations from initially unifonn systems. Turmg s paper was set in the context of the development of fonn (morphogenesis) in embryos, and has been adopted in some studies of animal coat markings. With the subsequent theoretical work at Brussels [1], it became clear that oscillatory chemical systems should provide a fertile ground for the search for experimental examples of these Turing patterns. 

Alan E. Mark, Heiko Schafer, Haiyan Liu, and Wilfred van Gunsteren ... 

Peter Deuflhard Jan Hermans Benedict Leimkuhler Alan E. Mark Sebastian Reich Robert D. Skeel... 

To a solution of 0.24 mol of lithium alanate in 500 ml of diethyl ether was added 0.20 mol of the acetylenic alcohol (note 1) at a rate such that gentle refluxing of the diethyl ether was maintained. After the addition the mixture was warmed under reflux for an additional 1 h. It was then cooled to 0 C and subsequently poured on to 400 g of finely crushed ice. After the remaining ice had melted the layers were separated (note 2). The aqueous layer was extracted several times with diethyl ether. The combined ethereal solutions were dried over magnesium sulfate and subsequently concentrated in a water-pump vacuum. Distillation of the residue through... 

To a solution of 8 g of lithiim alanate in 250 ml of diethyl ether was added in 15 min 24 g (0.3 mol) of 2-penten-4-yn-l-ol (III, Exp. 57). The diethyl ether began to reflux and a rubber-like greyish precipitate was formed. After heating for 1 h under reflux the flask was placed in an ice + ice-water bath and water (150 ml) was added dropwise with vigorous stirring. After this hydrolysis procedure the ethereal solution was decanted and the aqueous jelly layer was extracted ten times with diethyl ether. The ethereal extracts were dried (without washing) over magnesium sulfate and subsequently concentrated in a water-pump vacuum. 

Common reducing agents are hydrogen in the presence of metallic or complex catalysts (e.g. Ni, Pd, Pt, Ru, Rh), hydrides (e.g. alanes, boranes, LIAIH, NaBHJ, reducing metals (e.g. Li, Na, Mg, Ca, Zn), and low-valent compounds of nitrogen (e.g. NjHj, NjHJ, phosphorus (e.g. triethyl phosphite, triphenyiphosphine), and sulfur (e.g. HO-CHj-SOjNa = SFS, sodium dithionite = Na S O. ... 

TABLE 11.25 Tolerances for Analytical Weights By Alan D. Westland with Fred E. Beamish. 

Before beginning an academic career I was, of course, a student. My interest in chemistry and teaching was nurtured by many fine teachers at Westtown Friends School, Knox College, and the University of North Carolina at Chapel ITill their collective influence continues to bear fruit. In particular, I wish to recognize David Macinnes, Alan ITiebert, Robert Kooser, and Richard Linton. 

Come Back to Me, words by Alan Jay Lerner, music by Burton Lane... 

Therm alane Heat- Transfer Fluids. Coastal Chemical Co. manufactures three heat-transfer fluids intended for Hquid-phase systems. 

Therm alane L is a synthetic paraffin intended for low temperature appHcations. Therm alane 600 and Therm alane 800 are synthetic paraffins. 

R. Wang and R. Schoenfeld, eds., Choleystokinin Antagonists, Alan R. Liss, Inc., New York. 

Al—Ti Catalyst for cis-l,4-PoIyisoprene. Of the many catalysts that polymerize isoprene, four have attained commercial importance. One is a coordination catalyst based on an aluminum alkyl and a vanadium salt which produces /n j -l,4-polyisoprene. A second is a lithium alkyl which produces 90% i7j -l,4-polyisoprene. Very high (99%) i7j -l,4-polyisoprene is produced with coordination catalysts consisting of a combination of titanium tetrachloride, TiCl, plus a trialkyl aluminum, R Al, or a combination of TiCl with an alane (aluminum hydride derivative) (86—88). 

Another group of isoprene polymerization catalysts is based on alanes and TiCl. In place of alkyl aluminum, derivatives of AlH (alanes) are used and react with TiCl to produce an active catalyst for the polymerization of isoprene. These systems are unique because no organometaHic compound is involved in producing the active species from TiCl. The substituted alanes are generally complexed with donor molecules of the Lewis base type, and they are Hquids or soHds that are soluble in aromatic solvents. The performance of catalysts prepared from AlHCl20(C2H )2 with TiCl has been reported (101). 

D. Bhattacharyya, R. Adams, and M. Williams, in D. Butterfield, ed.. Biological and Synthetic Membranes, Alan R. Liss, New York, 1989. 

High Peformance Natural Polymers, Leaflet by Asiatic Development Berhad, Wisma Genting, J alan Sultan Ismail, Kuala Lumpui, 1993. 

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