A process can prepare an isocyanurate compound by hydrosilylation. The compound is a tris[3-(trialkoxysilyl)propyl] isocyanurate, a tris[3-(alkyldialkoxysilyl)propyl] isocyanurate, and/or a tris[3-(dialkylalkoxysilyl)propyl] isocyanurate, The process includes (A) preparing a mixture of at least one carboxylic acid, a platinum catalyst, and 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione; (B) heating the mixture to a temperature in the range of 40 to 140° C.; (C) adding at least one H-silane among a hydrotrialkoxysilane, a hydroalkyldialkoxysilane, and a hydrodialkylalkoxysilane to the mixture; (D) adding at least one alcohol to the mixture prepared in step (C); and (E) isolating the isocyanurate compound.