Claims
- 1. A method for forming a silicoaluminophosphate (SAPO) molecular sieve comprising:
providing a source of a silicon-containing composition; providing a source of an aluminum-containing composition; providing a source of a phosphorous-containing composition; providing a template; forming a reaction mixture sufficient to form a SAPO molecular sieve from said source of a silicon-containing composition, said source of an aluminum-containing composition, said source of a phosphorous-containing composition, and said template, said reaction mixture having a first pH; determining a pH increase in said reaction mixture such that said reaction mixture has a second pH higher than said first pH; and adding, after said determining said pH increase, an acid to said reaction mixture to adjust said second pH to from said first pH plus about one pH unit to said first pH minus about one pH unit.
- 2. The method of claim 1 further including the step of heating said reaction mixture prior to said step of determining said pH increase.
- 3. The method of claim 2 further including the step of forming of said crystals after said step of adding an acid to said reaction mixture.
- 4. The method of claim 1 wherein said acid is added to said reaction mixture at least two times.
- 5. The method of claim 4 wherein said acid is added to said reaction mixture discontinuously.
- 6. The method of claim 4 wherein said acid is added to said reaction mixture continuously.
- 7. The method of claim 1 wherein said template is a dual template.
- 8. The method of claim 6 wherein said dual template comprises tetraethylammonium hydroxide and dipropylamine.
- 9. The method of claim 1 wherein said source of a phosphorous-containing composition and said template are both tetraethylammonium phosphate.
- 10. The method of claim 2 further including the steps of cooling said reaction mixture prior to said adding of said acid to said reaction mixture and heating said reaction mixture after said acid is added to said reaction mixture.
- 11. The method of claim 1 wherein said acid is selected from the group consisting of phosphoric acid, hydrochloric acid, nitric acid, carbonic acid, sulfuric acid, acetic acid and formic acid.
- 12. The method of claim 1 wherein said second pH of said reaction mixture is adjusted to from said first pH plus about 0.5 pH unit to said first pH minus about 0.5 pH unit.
- 13. The method of claim 12 wherein said pH of said reaction mixture is adjusted to a pH from said first pH plus about 0.2 pH unit to said first pH minus about 0.2 pH unit.
- 14. The method of claim 1 wherein said SAPO molecular sieve is SAPO-34.
- 15. The method of claim 3 further including the steps of:
dissolving at least a portion of said crystals of said SAPO molecular sieve in said reaction; adding an acid to said reaction mixture; and re-crystallizing crystals of said SAPO molecular sieve from said reaction mixture.
- 16. The method of claim 15 wherein said re-crystallizing is performed at or above room temperature.
- 17. The method of claim 16 further including the step of heating said reaction mixture to facilitate said re-crystallizing of said SAPO molecular sieve.
- 18. The method of claim 1 wherein said silicoaluminophosphate molecular sieve is selected from the group consisting of SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO40, SAPO41, SAPO42, SAPO44, SAPO47, SAPO-56, and the metal substituted forms thereof.
- 19. The method of claim 18 wherein said silicoaluminophosphate molecular sieve is selected from the group consisting of SAPO-5, SAPO-11, SAPO-20, SAPO-31, SAPO-34, and SAPO42, and the metal substituted forms thereof.
- 20. A method for making a silicoaluminophosphate (SAPO) molecular sieve from a reaction mixture comprising components present in amounts sufficient to form said SAPO, said reaction mixture having a first pH, said method comprising:
adding an acid to said reaction mixture after said reaction mixture undergoes a change in pH from said first pH; and crystallizing said SAPO from said reaction mixture.
- 21. The method of claim 20 further including the step of heating said reaction mixture prior to said adding of said acid.
- 22. The method of claim 20 wherein said adding of said acid provides said reaction mixture with a pH of from said first pH plus about one pH unit to said first pH minus about one pH unit.
- 23. The method of claim 20 wherein said adding of said acid provides said reaction mixture with a pH of from said first pH plus about 0.5 pH unit to said first pH minus about 0.5 pH unit.
- 24. The method of claim 23 wherein said adding of said acid provides said reaction mixture with a pH of from said first pH plus about 0.2 pH unit to said first pH minus about 0.2 pH unit.
- 25. The method of claim 22 wherein said first pH is from about 5.5 to about 8.5 and said adding of said acid provides said reaction mixture with a pH of from about 5.5 to about 8.5.
- 26. The method of claim 25 wherein said first pH is from about 6 to about 8 and said adding of said acid provides said reaction mixture with a pH of from about 6 to about 8.
- 27. The method of claim 26 wherein said first pH is from about 6 to about 8 and said adding of said acid provides said reaction mixture with a pH of from about 6.2 to about 7.8.
- 28. The method of claim 20 wherein said acid is selected from the group consisting of phosphoric acid, hydrochloric acid, nitric acid, carbonic acid, sulfuric acid, acetic acid and formic acid.
- 29. The method of claim 20 wherein said adding of said acid is performed continuously.
- 30. The method of claim 20 wherein said adding of said acid is performed discontinuously.
- 31. The method of claim 21 further including the steps of cooling said reaction mixture prior to said adding of said acid to said reaction mixture and heating said reaction mixture after said acid is added to said reaction mixture.
- 32. A method for forming a silicoaluminophosphate 34 (SAPO-34) molecular sieve, said method comprising:
providing a source of a silicon-containing composition; providing a source of an aluminum-containing composition; providing a source of a phosphorous-containing composition; providing a template; forming a reaction mixture sufficient to form SAPO-34 from said source of a silicon-containing composition, said source of an aluminum-containing composition, said source of a phosphorous-containing composition, and said template, said reaction mixture having a first pH of from about 5.5 to about 8.5; determining a change in pH of said reaction mixture such that said reaction mixture has a second pH higher than said first pH; and adding, after determining said change in pH, an acid to said reaction mixture to adjust said second pH of said reaction mixture to a pH of from about 5.5 to about 8.5.
- 33. The method of claim 32 further including the step of heating said reaction mixture after forming said reaction mixture.
- 34. The method of claim 32 further including the step of forming crystals of said SAPO-34 after said step of adding said acid to said reaction mixture.
- 35. The method of claim 32 wherein said adding-of said acid to said reaction mixture occurs at least two times.
- 36. The method of claim 35 wherein said adding of said acid to said reaction mixture occurs discontinuously.
- 37. The method of claim 35 wherein said adding of said acid to said reaction mixture occurs continuously.
- 38. The method of claim 34 wherein said template is a dual template.
- 39. The method of claim 38 wherein said dual template comprises tetraethylammonium hydroxide and dipropylamine.
- 40. The method of claim 32 wherein said source of a phosphorous-containing composition and said template are both tetraethylammonium phosphate.
- 41. The method of claim 32 further including the steps of cooling said reaction mixture prior to said adding of said acid to said reaction mixture and heating said reaction mixture after said acid is added to said reaction mixture.
- 42. The method of claim 32 wherein said acid is selected from the group consisting of ortho-phosphoric acid, phosphoric acid, hydrochloric acid, nitric acid, carbonic acid, acetic acid and formic acid.
- 43. The method of claim 32 wherein said first pH of said reaction mixture is from about 6 to about 8 and said second pH of said reaction mixture is adjusted to a pH of from 6 to 8 after said adding said acid to said reaction mixture.
- 44. The method of claim 43 wherein said first pH of said reaction mixture is from about 6 to about 8 and said second pH of said reaction mixture is adjusted to a pH of from 6.2 to 7.8 after said adding said acid to said reaction mixture.
- 45. The method of claim 32 wherein said source of a silicon-containing composition is a silica sol, pyrogenic silica or a silicium alkoxide; said source of an aluminum-containing composition is pseudo-boehmite or aluminum alkoxide; said source of a phosphorous-containing composition is phosphoric acid; and said template is selected from the group consisting of TEAOH and a mixture of TEAOH and DPA.
- 46. A silicoaluminophosphate molecular sieve made by the process of claim 1.
- 47. A silicoaluminophosphate molecular sieve made by the process of claim 20.
- 48. A SAPO-34 molecular sieve made by the process of claim 32.
- 49. A method for converting an oxygenate to an olefin, said method comprising contacting an oxygenate with a silicoaluminophosphate (SAPO) molecular sieve catalyst under conditions effective to convert said oxygenate to an olefin, wherein said SAPO molecular sieve is made by the process comprising the following steps:
providing a source of a silicon-containing composition; providing a source of an aluminum-containing composition; providing a source of a phosphorous-containing composition; providing a template; forming a reaction mixture sufficient to form a SAPO molecular sieve from said source of a silicon-containing composition, said source of an aluminum-containing composition, said source of a phosphorous-containing composition, and said template, said reaction mixture having a first pH; determining a pH increase in said reaction mixture such that said reaction mixture has a second pH higher than said first pH; and adding, after said determining said pH increase, an acid to said reaction mixture to adjust said second pH to from said first pH plus about one pH unit to said first pH minus about one pH unit.
- 50. The method of claim 49 further including the step of heating said reaction mixture prior to said step of determining said pH increase.
- 51. The method of claim 50 further including the step of forming of said crystals after said step of adding an acid to said reaction mixture.
- 52. The method of claim 51 wherein said acid is added to said reaction mixture at least two times.
- 53. The method of claim 52 wherein said acid is added to said reaction mixture discontinuously.
- 54. The method of claim 52 wherein said acid is added to said reaction mixture continuously.
- 55. The method of claim 49 wherein said template is a dual template.
- 56. The method of claim 55 wherein said dual template comprises tetraethylammonium hydroxide and dipropylamine.
- 57. The method of claim 49 wherein said source of a phosphorous-containing composition and said template are both tetraethylammonium phosphate.
- 58. The method of claim 49 further including the steps of cooling said reaction mixture prior to said adding of said acid to said reaction mixture and heating said reaction mixture after said acid is added to said reaction mixture.
- 59. The method of claim 51 wherein said acid is selected from the group consisting of phosphoric acid, hydrochloric acid, nitric acid, carbonic acid, sulfuric acid, acetic acid and formic acid.
- 60. The method of claim 49 wherein said second pH of said reaction mixture is adjusted to from said first pH plus about 0.5 pH unit to said first pH minus about 0.5 pH unit.
- 61. The method of claim 60 wherein said pH of said reaction mixture is adjusted to a pH from said first pH plus about 0.2 pH unit to said first pH minus about 0.2 pH unit.
- 62. The method of claim 49 wherein said silicoaluminophosphate molecular sieve is selected from the group consisting of SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO40, SAPO41, SAPO42, SAPO44, SAPO47, SAPO-56, and the metal substituted forms thereof.
- 63. The method of claim 62 wherein said silicoaluminophosphate molecular sieve is selected from the group consisting of SAPO-5, SAPO-11, SAPO-20, SAPO-31, SAP0-34, and SAPO-42, and the metal substituted forms thereof.
- 64. The method of claim 49 wherein said SAPO molecular sieve is SAPO-34.
Priority Claims (1)
Number |
Date |
Country |
Kind |
PCT/RO99/00015 |
Oct 1999 |
WO |
|
PRIORITY CLAIM
[0001] This Application claims priority to PCT Application No. PCT/RO99/00015, filed Oct. 1, 1999 and entitled “Process for the Synthesis of Silicoaluminophosphate Molecular Sieves.”
Divisions (1)
|
Number |
Date |
Country |
Parent |
09677492 |
Oct 2000 |
US |
Child |
10335613 |
Dec 2002 |
US |