(2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanal → Glucose galactose

An SMB unit (available from Orochem Technologies Inc., Lombard, Ill.) was configured as a combination of 30 columns divided equally into 3 circuits. Each circuit contained 10 columns. The size of each column was 14 inches in diameter×65 inches in length (35.56 cm×165.1 cm) and had an empty volume of 150 liters. Each column was packed with 117 kg of Dowex 99CA/320 resin (Available from the Dow Chemical Company, Midland, Mich.), a strong acid cation calcium exchange resin stationary phase. The 30 columns were mounted on a rotating carousal. A fluid distribution valve was located at the center of the unit. Flow rates were controlled through control panel by adjusting valves and pump rates. Each circuit was divided into 4 different zones in a 2-3-2-2 configuration. (See FIG. 5) At step 1, feed was pumped into column 705 and Raffinate was withdrawn from (faster moving components/salts) column 707. Desorbent was pumped to column 701 and extract (slower moving component/sugars) was withdrawn from column 702. Part of extract is pumped back into the column 703 and part of raffinate is pumped into column 708 and was withdrawn as Raffinate Bleed. Raffinate bleed is pumped back into column 709 to push residual desorbent out and recycle. Column 710 is stationary at any given step in order to avoid back mixing of fluids within intermediate circuits. The desorbent was RO water (reverse osmosis) at low conductivity. A 45/45 wt-% based on sugar ratio of d-glucose to d-galactose syrup at 25-35 Brix obtained from evaporator 603, (See FIG. 4) was pumped into SMB 604 as feed at 0.5 L/min. The desorbent in line 800 (FIG. 5) is RO water (reverse osmosis) at low conductivity pumped at 8.5 L/min. An extract stream in lines 818 and 820 was withdrawn at a rate of 1.5 L/min and a raffinate stream in lines 838 and 840 was withdrawn at a rate of 7.4 L/min. Part of raffinate stream was pumped back into SMB as raffinate bleed in line 840 at 5.5 L/min and residual desorbent was passed to a desorbent tank (Not Shown). The SMB unit was maintained at a temperature of 65° C., and the step time was 780 seconds (13 min). The SMB unit provided an extract stream comprising d-galactose having a purity of about 80 wt-% of sugar, at a recovery about 95 wt-% based on sugar. The raffinate stream is 90-95 wt % of sugar as d-glucose syrup which was sent to evaporator to concentrate to provide a commercial glucose product.