silica having an enhanced level of dehydration beyond what can be produced by heating alone is produced by a three step process comprising chlorination , dechlorination , and oxidation . the resulting dehydroxylated silica is a novel composition of matter and is useful as a reinforcing agent in rubber or plastics and as a support for a chromatographic column in addition to being suitable for a catalyst support . where the dechlorinating agent is hydrogen , a hydrophobic silica composition containing . tbd . si -- h structures and essentially no -- oh groups is produced which is suitable for use as a reducing agent , a coupling agent as well as a precursor for the oxidized dehydroxylated silica described above .