A Novel Titanosilicate with MWW Structure. I. Hydrothermal Synthesis, Elimination of Extraframework Titanium, and Characterizations

摘要: A novel titanosilicate with MWW topology, Ti-MWW, has been prepared by an acid treatment on a corresponding lamellar precursor which is hydrothermally synthesized the coexistence of boron and titanium using piperidine (PI) or hexamethyleneimine (HM) as structure-directing agent. The can be to have Si/Ti ratio low 10 when Si/B gel maintained at 0.75. Both materials PI HM exhibit crystal form thin platelets, while latter shows larger size. Besides tetrahedral Ti species, always contains octahedral species showing UV−vis band 260 nm, regardless content. Calcination results in partial condensation anatase phase, hardly removed treatment. MWW-type nearly free both boron, however, successively cyclic precursor, tha...