Silica-supported hexaalkylguanidinium (SIGCl), tetraalkylammonium (SiNCl) and tetraalkylphosphonium (SiPCl) chlorides were tested and compared for the obtention of chloroalkanes from chloroformates through a S(N)2 pathway. The superiority of SiGCl appears clearly from the collected data. Conversion times are largely dependent upon the morphology of the silica, but conditions quite close to those obtained with the hexabutylguanidinium chloride could be obtained; the decomposition of the 2-chlorooctyl chloroformate with SiGCl is apart, since there is a competition between the thermal S(N)i and the catalytic S(N)2 routes which could not be totally avoided.