Molecular sieve SSZ-121 with high acidity, its synthesis and use
View Patent ↗A novel synthetic crystalline aluminogermanosilicate molecular sieve material, designated SSZ-121 is provided which exhibits increased acidity. The SSZ-121 can be synthesized using 1,3-bis(1-adamantyl)imidazolium cations as a structure directing agent. The synthesis employs a boron pathway to achieve increased acid sites. The SSZ-121 of increased acidity may be used in organic compound conversion reactions and/or sorptive processes.
1 . A method of synthesizing a SSZ-121 molecular sieve having increased acid sites, the method comprising:
(1) preparing a reaction mixture comprising:
(a) a FAU framework type zeolite having a SiO 2 /Al 2 O 3 mol ratio of at least 300;
(b) a source of germanium;
(c) a source of boron;
(d) a structure directing agent comprising 1,3-bis(1-adamantyl)imidazolium cations (Q);
(e) a source of fluoride ions; and
(f) water;
(2) subjecting the reaction mixture to crystallization conditions sufficient to form crystals of a molecular sieve containing boron;
(3) removing structure directing agent (Q); and
(4) replacing some of the boron in the crystals of the molecular sieve with aluminum.
2 . The method of claim 1 , wherein the reaction mixture has a composition, in terms of molar ratios, as follows:
(SiO 2 + GeO 2 )/B 2 O 3
≥10
Q/(SiO 2 + GeO 2 )
0.10 to 1.00
F/(SiO 2 + GeO 2 )
0.10 to 1.00
H 2 O/(SiO 2 + GeO 2 )
2 to 10.
3 . The method of claim 1 , wherein the reaction mixture has a composition, in terms of molar ratios, as follows:
(SiO 2 + GeO 2 )/B 2 O 3
15 to 20
Q/(SiO 2 + GeO 2 )
0.20 to 0.70
F/(SiO 2 + GeO 2 )
0.20 to 0.70
H 2 O/(SiO 2 + GeO 2 )
4 to 8.
4 . The method of claim 1 , wherein the FAU framework type zeolite is zeolite Y.
5 . The method of claim 1 , wherein the crystallization conditions include a temperature of from 100° C. to 200° C.
6 . The method of claim 1 , wherein the reaction mixture has a molar ratio of Q/F in a range of from 0.8 to 1.2.
7 . The process of claim 1 , wherein the Q is removed by calcination.
8 . The process of claim 1 , wherein the Q is removed by treatment with ozone.
9 . The process of claim 1 , wherein the replacing of boron with aluminum comprises refluxing the molecular sieve crystals with a solution of aluminum nitrate.