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JP-7856667-B2 - Synthesis of TON-framed molecular sieves

JP7856667B2JP 7856667 B2JP7856667 B2JP 7856667B2JP-7856667-B2

Inventors

  • シュミット、ジョエル エドワード
  • オジョ、アデオラ フローレンス

Assignees

  • シェブロン ユー．エス．エー． インコーポレイテッド

Dates

Publication Date
20260511
Application Date
20220128
Priority Date
20210211

Claims (10)

  1. A method for synthesizing TON-framed molecular sieves, (1) Below: (a) A supply source comprising silicon and aluminum, wherein the supply source comprising silicon and aluminum is alumina-coated silica; (b) A structural modifier (Q) containing a 1,3,4-trimethylimidazolium cation; (c) Sources of hydroxide ions; (d) water; and (e) seed crystal, which forms a reaction mixture containing a seed crystal comprising a TON-framed molecular sieve. (2) A method for synthesizing a TON-skeleton molecular sieve, comprising maintaining the reaction mixture under crystallization conditions including a temperature of 125°C to 200°C and a time of 1 to 10 days in order to form crystals of the TON-skeleton molecular sieve, The reaction mixture, in terms of molar ratio, is as follows: A method for synthesizing a TON-framed molecular sieve having the composition described above.
  2. The reaction mixture, in terms of molar ratio, is as follows: The method according to claim 1, having the composition as described above.
  3. The method according to claim 1, wherein the source of hydroxide ions includes an alkali metal hydroxide.
  4. The method according to claim 3 , wherein the alkali metal of the alkali metal hydroxide is lithium, sodium, potassium, or a mixture thereof.
  5. The method according to claim 4 , wherein the molar ratio of alkali metal cation to SiO2 is in the range of 0.1 to 1.0.
  6. The method according to claim 1, wherein the reaction mixture contains 0.01 ppm by weight to 10,000 ppm by weight of seed crystals.
  7. The method according to claim 1, wherein the reaction mixture further comprises another silicon source.
  8. The method according to claim 7 , wherein the other silicon source comprises colloidal silica, precipitated silica, fumed silica, alkali metal silicates, tetraalkyl orthosilicates, or mixtures thereof.
  9. The method according to any one of claims 1 to 8 , wherein the as-synthesized TON-framed molecular sieve is heat-treated to remove some or all of the structural modifier.
  10. The method according to claim 9 , wherein the TON-skeleton type molecular sieve is mixed with a metal hydride component.

Description

This disclosure relates to an improved method for preparing molecular sieves having a TON framework structure, and to the use of such molecular sieves in catalytic conversion processes of hydrocarbon compounds. Molecular sieve materials are classified by the Structural Committee of the International Zeolite Association in accordance with the rules of the IUPAC Committee on Zeolite Nomenclature. According to this classification, structurally established skeletal zeolites and other crystalline microporous materials are assigned a three-letter code and are listed in the "Atlas of Zeolite Framework Types," 6th revised edition, Elsevier (2007). One known molecular sieve with an established structure is a material called TON, which is a molecular sieve possessing a unique one-dimensional 10-membered ring channel system. Examples of TON-frame molecular sieves include ISI-1, KZ-2, NU-10, Theta-1, and ZSM-22. TON-frame materials are of commercial interest due to their catalytic activity in the dewaxing of paraffinic hydrocarbons. According to this disclosure, it has been found that using 1,3,4-trimethylimidazolium cations as a structure-controlling agent and aluminosilicate starting materials allows for the synthesis of TON-type molecular sieves through a simpler process and with a shorter heating period than previously possible. These materials enable the production of TON-type molecular sieves with unique morphological and physicochemical properties. Furthermore, it is possible to produce TON-type molecular sieves with smaller crystal sizes. In the first embodiment, a method for synthesizing a TON-framed molecular sieve is provided, comprising: (1) forming a reaction mixture containing: (a) a silicon-aluminum combined source, which is alumina-coated silica, a FAU-framed aluminosilicate zeolite, or a mixture thereof; (b) a structure-determining agent (Q) containing a 1,3,4-trimethylimidazolium cation; (c) a hydroxide ion source; (d) water; and (e) a seed crystal; and (2) maintaining the reaction mixture under crystallization conditions sufficient to form a molecular sieve crystal. In a second embodiment, a TON-frame molecular sieve containing a 1,3,4-trimethylimidazolium cation in its pores in the as-synthesized form is provided. In a third embodiment, a hydrogen isomerization process for a paraffinic hydrocarbon feedstock is provided, comprising contacting the paraffinic hydrocarbon feedstock with a catalyst containing hydrogen and a TON-framed molecular sieve under hydrogen isomerization conditions, and obtaining a product in which branched hydrocarbons are increased compared to the hydrocarbon feedstock, wherein the catalyst further contains 0.01 to 10% by weight of a precious metal. In connection with the present invention, the following is further disclosed. [1] A method for synthesizing TON-framed molecular sieves, (1) Below: (a) A silicon-aluminum combined source, wherein the silicon-aluminum combined source is alumina-coated silica, FAU-framed aluminosilicate zeolite, or a mixture thereof; (b) A structural modifier (Q) containing a 1,3,4-trimethylimidazolium cation; (c) Sources of hydroxide ions; (d) water; and (e) Seed crystal Forming a reaction mixture containing, (2) The method comprising maintaining the reaction mixture under crystallization conditions sufficient to form crystals of the molecular sieve. [2] The reaction mixture, in terms of molar ratio, is as follows: The method according to [1], having the composition as described above. [3] The reaction mixture, in terms of molar ratio, is as follows: The method according to [1], having the composition as described above. [4] The method according to [1], wherein the FAU skeleton-type aluminosilicate zeolite is zeolite Y. [5] The method according to [1], wherein the source of hydroxide ions comprises an alkali metal hydroxide. [6] The method according to [5], wherein the alkali metal is lithium, sodium, potassium, or a mixture thereof. [7] The method according to [6], wherein the molar ratio of alkali metal cation to SiO2 is in the range of 0.1 to 1.0. [8] The method according to [1], wherein the seed crystal comprises a TON-skeleton type molecular sieve. [9] The method according to [1], wherein the reaction mixture contains 0.01 ppm by weight to 10,000 ppm by weight of seed crystals. [10] The method according to [1], wherein the reaction mixture further comprises another silicon source. [11] The method according to [10], wherein the other silicon source comprises colloidal silica, precipitated silica, fumed silica, alkali metal silicates, tetraalkyl orthosilicates, or mixtures thereof. [12] The method according to [1], wherein the crystallization conditions include a temperature of 125°C to 200°C and a time of 1 to 10 days. [13] A TON-frame molecular sieve containing 1,3,4-trimethylimidazolium cations in its pores in its as-synthesized form. [14] The molecular sieve according to [13], wherein the molar ratio of SiO₂/Al₂O₃ is in the range of 30 to 10