| 摘要 |
PURPOSE:To obtain macropore-containing ZSM-5 zeolite having high air permeability by mixing a synthetic liquid of pentasil type zeolite having an extremely reduced moisture content with diatomaceous earth, increasing the temperature according to program heating, crystallizing the mixture, burning the resultant crystals, exchanging Na ions with NH4 ions, further drying and burning the prepared crystals. CONSTITUTION:A chemical equivalent amount of a tetraalkylammonium bromide and NaAlO2 are successively dissolved in an aqueous solution of sodium hydroxide in an amount corresponding to the composition of the chemical composition 0.30tetraalkylammonium:0.20Na:0.001-0.025Al:7.5H2O to prepare an aqueous mixture solution. Diatomaceous earth is then mixed and kneaded with the resultant solution and temperature thereof is increased from ambient temperature to 120-250 deg.C by program heating to slightly dissolve the surface of the diatomaceous earth. The obtained mixture is used as a silica source to crystallize ZSM-5 zeolite. The formed crystals are then burned at 500-600 deg.C in an air stream and Na ions in the ZSM-5 are subjected to ion exchange with NH4 ions. The resultant crystals are subsequently dried and burned at 500-600 deg.C. |
