Indirect hydrolysis of sodium borohydride: Isolation and crystallographic characterization of methanolysis and hydrolysis by-products

• Hydrogen generation was achieved through methanolysis of NaBH4 using rigorously dried methanol.
• The methanolysis by-product was determined, by single-crystal X-ray diffraction analysis, to be [Na2(B(OCH3)4)2(CH3OH)2]4.
• Hydrolysis of the NaBH4 methanolysis by-product releases trapped methanol.
• The hydrolysis by-product was determined by crystallography to be Na2[B4O5(OH)4]·8/3H2O.

The use of sodium borohydride as a means for hydrogen generation has focused on the base-stabilized hydrolysis reaction, while literature for the methanolysis of sodium borohydride remains scarce. Sodium borohydride methanolysis is an alternative for hydrogen production from sodium borohydride and has a number of advantages over hydrolysis reactions in terms of by-product handling. Previous studies have shown that the presence of water in methanol significantly retards the rate of hydrogen evolution from NaBH4. This article reports the production of hydrogen from NaBH4 using rigorously dried methanol. In addition, the solid-state structure of the methanolysis by-product is reported, which lends pertinent information for its hydrolysis for methanol recovery. Also reported is the solid-state structure of the hydrolysis by-product.

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