Column chromatography eluent concentration gradient

A mixture of 6.3 g Mo(CO)6 (24 mmol) and 120 mL toluene was heated to 50°C for 2 hours to form a saturated solution. After that, a solution of 1.35 g ortho-ester (2.43 mmol) and 2.01 g DMSO (26 mmol) in 20 mL dry toluene was added. The resulting mixture was heated at 53-55°C for 36 h and then was filtered to remove the solids. The precipitate was washed with hexanes (2 x 20 mL). The combined organic layers were concentrated under reduced pressure, and the residue was purified by gradient silica gel column chromatography using hexanes/EtOAc (100 0-95 5) as the eluent, to afford 0.96 g tetraene, in a yield of 66%. This tetraene can be further purified by crystallization from hexanes. 

The first results of optimization in chromatography were published in 1975 Since then a growing number of optimization experiments in HPLC using the Simplex procedure has been reported (table 9). The examples are mainly reversed-phase separations, in which the composition of the ternary or binary mobile phase composition is optimized. The factors optimized are usually a selection from flow rate, column temperature and length, the eluents constitution (e.g. organic modifier content, buffer concentration and pH), the gradient shape. Seven years after the first applications of Simplex optimization had appeared, the first fully automated optimization of HPLC separations was published by Berridge in 1982. This development coincid-... 

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