Liquid chromatography pouring columns

The products obtained were analyzed for composition using high-performance liquid chromatography (HPLC) (LC -10AT Shimadzu, Kyoto, Japan), which consisted of a column (STR ODS-II, 25 cm in length x 4.6 mm in id Shinwa Chemical, Osaka, Japan) operated at 40°C at a flow rate of 1.0 mL/min with methanol as a carrier solvent. The column was packed with silica particles (5-pm particle diameter and 12-nm pore diameter). The cloud and pour points of the obtained biodiesel were then determined by a mini-cloud/pour point tester (Model MPC-102 Tanaka Scientific, Tokyo, Japan) based on ASTM D2500 for cloud point and ASTM D6749 for pour point (14). 

The crude product is dissolved in diethyl ether / petroleum ether (1 5) (5 mL) and poured onto a column (45-mm diameter) filled with 200 g of silica gel (Merck 230-400 mesh for flash chromatography). Elution (Note 23) under pressure (Note 14) with diethyl ether / petroleum ether (1 5) gives 2-oxo-5-methoxyspiro[5.4]decane as a colorless liquid (4.43 g 75%) (Note 24). 

The step 1 product (21 g) was dissolved in 210 ml of CH2CI2 and then treated with 77% m-chloroperbenzoic acid (41.6 g) at ambient temperature for 6 hours. The mixture was then poured into a solution of sodium hydroxide (40 g) dissolved in 150 ml of water and 200 ml of hexane and then stirred and cooled to 10°C using an ice bath. The organic layer was isolated and washed once with 100 ml of 5% Na2S204 and three times with 100 ml of 10% KC1 solution. The mixture was concentrated and the residue purified using silica gel column chromatography with hexane/ ethyl acetate, 3 1, respectively. An oil, which was obtained, was dissolved in 100 ml of 10% ethyl acetate in hexane and treated with basic aluminum oxide (3 g) to remove color on the product. After filtration 13 g of product were isolated as a liquid. 

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