To obtain an surface-coated inorganic substance which has a sulfonic acid group on its surfaces and excels in surface hydrophilicity and dispersibility in water by coating the surface of an inorganic substance with a specific alkoxysilane compound and hydrolyzing or thermally decomposing the alkoxysilane compound.
A surface-coated inorganic compound having a surface coating whose structure is expressed by formula III (X is H, an alkali metal or ammonium), is obtained by forming, on the surface of an inorganic substance such as silica, Ti dioxide or alumina, a coating of an alkoxysilane compound (e.g. formula II) which is shown by formula I (R1 is a 1-6C alkyl; R2 is a 1-3C alkyl or phenyl; R3 is a 1-8C alkyl; Y is phenylene; (m) is 1-3; (n) is O-2; (m+n)=3; (p) is 2 or 3) and has a sulfonic acid ester group at its terminal, and by decomposing the sulfonic acid ester group in the coating by hydrolysis or thermal decomposition. This surface-coated inorganic substance excels in ability to capture basic compounds and metal ions and useful as a base scavenger, etc.
YAMASHITA YUKIYA
KAWAMURA KYOKO
SAKURAI HIDEAKI
