Methods of preparing an organic sol of particles are provided. Steps include providing a suspension of particles in an aqueous medium; adding a first organic liquid compatible with the aqueous medium to form an admixture; reacting the particles with a first and a second modifying compound; adding a second organic liquid compatible with the liquid portion of the admixture wherein the second organic liquid is different from the first organic liquid; and maintaining the admixture at a temperature and pressure and for a time sufficient to substantially remove the water and the first organic liquid. Also provided are curable film-forming compositions containing sols of particles prepared by the methods of the present invention.