TH52669A - Methods for producing titanium packed zeolite - Google Patents

Abstract

DC60 (18/05/44) This invention relates to a method for the production of titanium-packed zeolites where a gel is synthesized by the incorporation and hydrolysis of hydrolyzable silicon compounds, hydrolyzable titanium compounds, and basic quaternary ammonium compounds in aquasodium in quantities similar to that of the starting compounds, with a molar ratio of Si/Ti greater than or equal to 30 and of N/Si 0.12 to less than 0.20. The synthesized gel is then crystallized at temperatures of 150 °C to 220 °C for a period of less than 3 days, and the titanium-packed zeolites obtained by this method are produced. The molar ratio of Si/Ti is greater than or equal to 30, and that of N/Si is between 0.12 and less than 0.20. A synthetic gel is then crystallized at temperatures of 150°C to 220°C for less than 3 days, resulting in titanium-containing zeolite obtained by this method.

Claims (12)

1. The method for producing titanium-encapsulated zeolites involves forming a synthetic gel by combining and hydrolyzing hydrolyzable silicon compounds, hydrolyzable titanium compounds, and basic quaternary ammonium compounds within aquasodium in quantities such that, compared to the starting compounds, the molar ratio of Si/Ti is greater than or equal to 30, and that of N/Si is 0.12 to less than 0.20. The synthetic gel is then crystallized at temperatures of 150°C to 220°C for a period of less than 3 days. 2. Method according to claim 1, where the molar ratio of N/Si is 0.12 to less than 0.17. 3. One of the preceding claims, where the molar ratio of H2O/Si relative to the starting compounds is 10 to 20. 4. Method according to claim 3, where the molar ratio of H2O/Si is 12 to 17. 5. Any of the preceding claims, where the hydrolyzable silicon compound is tetraalkyl orthosilicate, preferably tetraethyl orthosilicate, and the hydrolyzable titanium compound is tetraalkyl orthothitanate, preferably tetraethyl orthothitanate. 6. The method under claim 5, whereby the hydrolysis of the hydrolyzed titanium and silicon compounds is supported by distillation of the resulting alcohol, and at least a portion of the volume of alcohol removed by distillation may be selectively replaced by the addition of water to the reaction mixture. 7. According to one of the preceding claims, the quaternary ammonium compound is tetraalkylammonium hydroxide, most commonly tetra-n-propylammonium hydroxide. 8. One of the preceding methods, where the pH of the crystallized suspension from the crystallization step is adjusted to a value of 7 to 10, preferably 7 to 8.5. 9. By any method under any prior claim, the titanium-containing zeolyze is separated, dried, and burned to ash. 10. Titanium-containing zeolites obtained by one of the previously claimed methods, with a primary crystal size of 0.2 to 2.0 micrometers. 11. The epioxidation method of olefins by reaction of olefins with aqueous hydrogen peroxide in a miscible solvent with water in the presence of a titanium-encrusted zealite as per claim 10 or obtained by the method of claim 9. 12. The use of titanium-encapsulated zeolites obtained by the method specified in Patent 10 or by the method specified in Patent 9 as a catalyst for the epioxidation of olefins with hydrogen peroxide.