Gas-chromatographic determination of the product distribution in the synthesis of sodium borohydride.

A gas-chromatographic method has been developed for determination of the sodium borohydride and methanol content of alkaline aqueous solutions of NaBH(4). From the ratio between NaBH(4) and CH(3)OH the product distribution in NaBH(4) synthesis from NaH and B(OCH(3))(3) in mineral oil can be calculated and the amount of the by-product NaBH(OCH(3))(3) formed can be estimated. A separation and extraction procedure for the mineral oil dispersion must precede the gas-chromatographic analysis. Sodium borohydride is determined by measurement of the 2-propanol formed after treatment of the solution with acetone, whereas methanol can be determined directly by gas chromatography, with 1-propanol as internal standard. The analysis of the synthesis products is thus the separation and detection of simple alcohols.