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US-12623909-B2 - Molecular sieve SSZ-121 with high acidity, its synthesis and use

US12623909B2US 12623909 B2US12623909 B2US 12623909B2US-12623909-B2

Abstract

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.

Inventors

  • Stacey I. Zones

Assignees

  • CHEVRON U.S.A. INC.

Dates

Publication Date
20260512
Application Date
20230530

Claims (9)

  1. 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. 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. 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. 4 . The method of claim 1 , wherein the FAU framework type zeolite is zeolite Y.
  5. 5 . The method of claim 1 , wherein the crystallization conditions include a temperature of from 100° C. to 200° C.
  6. 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. 7 . The process of claim 1 , wherein the Q is removed by calcination.
  8. 8 . The process of claim 1 , wherein the Q is removed by treatment with ozone.
  9. 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.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application claims priority to U.S. Provisional Application No. 63/365,527, filed May 31, 2022, the complete disclosure of which is incorporated herein by reference in its entirety. FIELD This disclosure relates to a novel synthetic crystalline aluminogermanosilicate molecular sieve designated SSZ-121 having increased acidity, and its synthesis. Zeolitic materials are known to have utility as sorbents and to have catalytic properties for various types of organic compound conversion reactions. Certain zeolitic materials are ordered, porous crystalline materials having a definite crystalline structure as determined by X-ray diffraction, within which there are a large number of smaller cavities which may be interconnected by a number of still smaller channels or pores. These cavities and pores are uniform in size within a specific zeolitic material. Since the dimensions of these pores are such as to accept for sorption molecules of certain dimensions while rejecting those of larger dimensions, these materials have come to be known as “molecular sieves” and are utilized in a variety of ways to take advantage of these properties. There are currently over 250 known zeolitic framework structures recognized by the International Zeolite Association. There exists a need for new structures, having different properties than those of known materials, for improving the performance of many organic compound conversion and sorption processes. Each structure has unique pore, channel and cage dimensions, which gives its particular properties as described above. Each framework structure also has a particular composition. Improvements in preparing more pure, single phase materials are always important. Providing molecular sieves with increased acid sites can be valuable with regard to the catalysis in organic compound conversion reactions. SUMMARY According to the present disclosure, a new crystalline aluminogermanosilicate molecular sieve, designated SSZ-121, with increased acid sites, and having a unique composition, has been synthesized using 1,3-bis(1-adamantyl)imidazolium cations as a structure directing agent. The synthesis is conducted through a boron pathway. The present SSZ-121 molecular sieve contains some boron in its framework. In one embodiment, the amount of boron can range from 50-250 ppm. The present aluminogermanosilicate SSZ-121 molecular sieve having increased acid sites and hence enhanced acidity, can have a chemical composition comprising the following molar relationship: TABLE 1BroadestSecondary(SiO2 + GeO2)/Al2O3≥30≥50 The SSZ-121 zeolite prepared also has increased acid sites and some boron in the framework. In one embodiment, there is provided a method of synthesizing the present SSZ-121 aluminogermanosilicate molecular sieve, the method comprising (1) providing a reaction mixture comprising: (a) a FAU framework type zeolite; (b) a source of germanium; (c) a source of boron; (d) a structure directing agent (Q) comprising 1,3-bis(1-adamantyl) imidazolium cations; (e) a source of fluoride ions; and (f) water; (2) subjecting the reaction mixture to crystallization conditions sufficient to form crystals of a boron germanosilicate molecular sieve; (3) removing structure directing agent (Q); and (4) treating the remaining crystals to replace boron in the framework with aluminum. Thus, the boron pathway involves preparing a germanosilicate molecular sieve comprising boron in the framework. The boron molecular sieve has in its as-synthesized form, a powder X-ray diffraction pattern including at least the following 2-theta scattering angles: 6.3±0.2; 7.0±0.2; 9.5±0.2; 13.0±0.2; 16.0±0.2; 18.5±0.2; 19.8±0.2; 21.2±0.2; 24.0±0.2; 25.0±0.2; 26.5±0.2; 28.5±0.2; and 30.0±0.2 degrees 2-theta. It is this boron germanosilicate molecular sieve that is then treated to replace the boron in the framework with aluminum, hence resulting in increased acid sites. In another embodiment, there is provided a process of converting a feedstock comprising an organic compound to a conversion product which comprises contacting the feedstock at organic compound conversion conditions with a catalyst comprising an active form of the aluminogermanosilicate molecular sieve, described herein. Among other factors, the present process allows one to obtain a SSZ-121 molecular sieve with increased acid sites, i.e., the SSZ-121 is acid rich or of enhanced acidity. By increased acid sites is meant that by using the present process with its boron pathway, a SSZ-121 molecular sieve can be obtained with more acid sites than would be possible by preparing the molecular sieve conventionally in a straight forward method with aluminum sites and no boron. When the conventional route is employed, it has been found that some amorphous phase occurs so a loss of Al acid sites is experienced. It has been found, quite surprisingly, that by first inserting boron in the framework, and then replacing the boron wit