Dimethylchlorosilane DMCS

Table 14 summarizes the data obtained in [59,60]. Here the chromatographic characteristics of the supports modified using the liquid phase method, are compared with those of the Chromaton N-AW support modified with dimethylchlorosilane (DMCS) from the gas phase. The degree of surface deactivation was calculated from the peak asjTnmetry factor As measured at 0.1 peak height. The efficiency of the chromatographic column was estimated from the value of the equivalent theoretical plate height (ETPH). The supports were loaded into the columns without the stationary liquid phase. 

The synthesis of the new MSSA is depicted in Scheme 1.2. The first step was the activation of the silica gel surface with HCI, then an excess of dimethylchlorosilane (DMCS) was used to accomplish the silanization process. Conversion of Si-Cl to Si-OH occurred when water was added to the solid product after 10 min of stirring at room temperature. After completion of all reactions, samples were dried in a nitrogen stream at 120°C for 24 h. Finally, the silanol groups were allowed to react with chlorosulfonic acid to yield the desired MSSA, without any side products as HCI gas evolved from the reaction vessel immediately. 

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