Filtration, problems with crystalline

A problem of stannylene procedures, which has not yet found a uniformly satisfactory solution, is the disposal of the tin by-products, which are insoluble in water. In a few very favorabla cases, treatment with methanol converted them to the crystalline compound Br-BUjSn-O-SnBUj-OH, which could be removed by filtration. In the other cases, silica gel column chromatography is always successful. The highly lipophile, dibutyltin compounds move to the front in nonpolar eluents. However, chromatography is a great inconvenience in large-scale work. 

A similar problem of clarification of cultural liquids also arises in the biotechnological production of nucleosides. In the Tripol e Biochemical Plant in (Ukraine), MN-200 exhibited, on the whole, better performance than commonly used activated carbons [48]. A comparative study of MN-200, Styrosorb IBP, Styrosorb 1 (MCDE, 100%), and granular activated carbon OU-A (Russia) was conducted by filtrating 200 mL cultural liquid of riboxin (inosine) production at 20°C or 250 mL aqueous saturated solution of technical crystalline riboxin at 60°C (to avoid nucleoside crystallization) through a 12 mL sorbent bed at a flow rate of 0.2-0.3mL/min. In both solutions pH was between 3.3 and 3.6. After rinsing the sorbents with water, they were regenerated with 100 mL 2 N NaOH. The results obtained are given in Table 11.3. 

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