Sulfuric Acid → (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanal

To 20 mL of an aqueous feedstock containing 12.6 wt. % L-mannose, 0.07 wt. % L-glucose, and 0.5 wt. % L-arabinose was added sodium molybdate in an amount calculated to afford the desired concentration of Mo. Solutions were adjusted to their desired pH by addition of 10% sulfuric acid and epimerization was followed with time. From the resulting plots of time glucose yield the time for conversion to a 60:40 glucose:mannose mixture (60% yield) was determined. The times as a function of temperature, Mo concentration, and pH are summarized in Table 2.