GLYCERIN DEHYDRATION CATALYST, AND ACROLEIN PRODUCTION PROCESS, ACRYLIC ACID PRODUCTION PROCESS AND HYDROPHILIC RESIN PRODUCTION PROCESS EACH USING THE CATALYST

摘要

Disclosed is a glycerin dehydration catalyst comprising a boron salt of phosphoric acid or a rare earth metal salt of phosphoric acid, wherein the molar ratio of phosphorus (P) to boron (B) (i.e., P/B) or the molar ratio of phosphorus (P) to the rare earth metal (R) (i.e., P/R) is more than 1.0 and not more than 2.0. The glycerin dehydration catalyst may comprise a boron salt of phosphoric acid and a metal element or a rare earth metal salt of phosphoric acid and a metal element (other than a rare earth metal), wherein the molar ratio of the metal element (M) to the sum total of phosphorus (P) and boron (B) (i.e., M/(P+B)) or the molar ratio of the metal element (M) to the sum total of phosphorus (P) and the rare earth metal (R) (i.e., M/(P+R)) is more than 0.00005 and not more than 0.5.