Vapor phase batch hydrolysis of NaBH4 at elevated temperature and pressure

✍ Scribed by Hong Liu; Christopher M. Boyd; Amy M. Beaird; Michael A. Matthews

• Book ID: 103833149
• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 617 KB
• Volume: 36
• Category: Article
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2011.02.104

✦ Synopsis

Complex chemical hydrides are a means to store hydrogen in the solid state near ambient temperatures and pressures. Hydrolysis of hydrides has the potential to provide high gravimetric and volumetric energy densities if water consumption can be minimized. At low temperatures (110w140 C), the product of NaBH 4 hydrolysis is NaBO 2 $2H 2 O (dihydrate), consuming 2 mol of unutilized water. The objective of this work was to conduct water vapor hydrolysis of NaBH 4 at elevated pressure and temperature above 150 C. It was hypothesized that this would yield a solid borate with decreased water bound in the crystal structure. A series of batch reactions were conducted to verify the hypothesis. Experimental characterization of the sodium metaborate byproducts indicated that the primary product of water vapor hydrolysis was NaBO 2 $1/3H 2 O (hemihydrate) under a variety of reaction conditions. For the most cases, the conversion of NaBH 4 approached 100%.