| 摘要 |
<p>The present invention relates to a process for the preparation of zeolites having B-CHA framework structure and a composition comprising the molar ratio (n SiO 2 ) : B 2 O 3 , wherein n is at least 10, the process comprising
(i) preparation of an aqueous solution containing at least one source for B 2 O 3 , at least one source for SiO 2 , at least one source of seeding crystals of chabazite structure, at least one organic structure directing agent (SDA) other than Tetramethylammonium hydroxide (TMAOH), acting as a template for the B-CHA structure, and Tetramethylammonium hydroxide (TMAOH), wherein the SDA or mixtures thereof are employed in such amounts that the aqueous solution in (i) exhibits a molar ratio of SDA : TMAOH of 0.01 to 5;
(ii) hydrothermal crystallization of the aqueous solution according to (i);
wherein the ratio of the [molar ratio (SiO 2 : B 2 O 3 )] of the gel composition : [molar ratio (SiO 2 : B 2 O 3 )] of the crystalline product having the chabazite structure is greater than 0.5. The present invention also relates to the zeolitic materials obtainable and/or obtained by this process as well as to a zeolitic material as such, having framework structure B-CHA, having a composition comprising the molar ratio (n SiO 2 ) : B 2 O 3 , wherein n is at least 10, and wherein the ratio of the [molar ratio (SiO 2 : B 2 O 3 )] of the gel composition: [molar ratio (SiO 2 : B 2 O 3 )] of the crystalline product having the chabazite structure is greater than 0.5.</p> |
