Method for quickly synthesizing small-crystallite titanium-silicon molecular sieve in cheap system

A titanium-silicon molecular sieve and small-grain technology, applied in the direction of crystalline aluminosilicate zeolite, etc., can solve the problems of severe reaction impact and low selectivity of the main product, simplify the separation process, shorten the synthesis cycle, and accelerate the crystallization rate Effect

Active Publication Date: 2010-12-15
DALIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The grain size obtained by this method is about 3 × 2 μm. Due to the large grain size, for the propylene epoxidatio

Method used

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  • Method for quickly synthesizing small-crystallite titanium-silicon molecular sieve in cheap system
  • Method for quickly synthesizing small-crystallite titanium-silicon molecular sieve in cheap system
  • Method for quickly synthesizing small-crystallite titanium-silicon molecular sieve in cheap system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036]1.4 mL of titanium tetrachloride was dropped into 12 mL of isopropanol, and stirred until the HCl was completely volatilized to obtain a solution of titanium tetrachloride in isopropanol. Add 81mL of deionized water to 100mL of 30wt% silica sol, stir for 10min, then mix with the alcohol solution of titanium tetrachloride, stir for 30min, then add 24g of tetrapropylammonium bromide, 50mL of 65wt% ethylamine aqueous solution, 12mL Nano-scale titanium-silicon molecular sieve mother liquor, and 78mL deionized water, after stirring for 30 minutes, the glue solution was added to a stainless steel crystallization kettle with a polytetrafluoroethylene liner, crystallized at 170°C for 24h, and the crystallized product was washed and dried. Calcined at 540°C for 6h to obtain TS-1, which is numbered as E. Its X-ray diffraction (XRD) spectrum is as figure 1 As shown, its Fourier transform infrared (FT-IR) spectrum is shown as figure 2 The scanning electron microscope (SEM) pictur...

Embodiment 2

[0038] The composition of all raw materials and the batching operation process are the same as in Example 1, except that the obtained titanium silica gel solution is crystallized at 170°C for 60 hours, and then undergoes the same post-treatment process to obtain TS-1, which is numbered as F, XRD spectrum and figure 1 Similar, but with higher relative crystallinity; IR spectrum and figure 2 Similarly, the titanium content of the framework basically did not change; SEM photos and image 3 Similarly, the grain size did not change significantly.

Embodiment 3

[0040] Since the mother liquor of nano-scale titanium-silicon molecular sieve contains excessive template agent TPAOH, which may have a certain impact on the crystallization process, the seed crystal is changed to nano-scale titanium-silicon molecular sieve powder, and then a certain amount is added to the synthesis of small-grain TS-1 TPAOH, to investigate the cause of the smaller grains of the small grain TS-1. Add 81mL deionized water to 100mL 30wt% silica sol, stir for 10min, then mix with 14mL alcohol solution of titanium tetrachloride, stir for 30min, then add 24g tetrapropylammonium bromide, 50mL65wt% ethylamine aqueous solution, 1g Nanoscale titanium-silicon molecular sieve powder, 25mL 0.12mol / L TPAOH, and 55mL deionized water, after stirring for 30 minutes, add the glue solution into a stainless steel crystallization kettle with PTFE lining, crystallize at 170°C for 36h, and crystallize After the product was washed and dried, it was calcined at 540°C for 6 hours to o...

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Abstract

The invention provides a method for preparing a small-crystallite titanium-silicon molecular sieve in a cheap system by changing the adding mode of seed crystals and by a hydrothermal process. The titanium-silicon molecular sieve is prepared by using silicon sol as a silicon source, titanium tetrachloride or tetrabutyl titanate as a titanium source, tetrapropylammonium bromide ( TPABr) as a template agent, organic amine as an alkali source and unseparated nanoscale TS-1 mother liquor as seed crystals directly and by the hydrothermal process. The grain size of the titanium-silicon molecular sieve is less than 1 micrometer, and the titanium-silicon molecular sieve has high activity for selective oxidization reactions using hydrogen peroxide as an oxidant, such as epoxidation of olefins, hydroxylation of phenol, ammoxidation of cyclohexanone and the like. The method simplifies the synthesis process of small crystallite TS-1 in the cheap system and reduces synthesis time and cost.

Description

technical field [0001] The invention relates to a method for synthesizing a titanium-silicon molecular sieve. Background technique [0002] In 1983, U.S. Patent No. 4410501 reported the synthesis of titanium-silicon molecular sieve TS-1 with MFI structure for the first time. It uses orthoethyl silicate (TEOS) or silica sol as silicon source, and tetraethyl titanate (TBOT) as titanium Source, tetrapropylammonium hydroxide (TPAOH) as template, crystallized in hydrothermal system for 6~30 days. [0003] Titanium-silicon molecular sieve TS-1 has excellent catalytic performance in the oxidation system composed of hydrogen peroxide, and shows high activity for olefin epoxidation, aromatic hydrocarbon hydroxylation, cyclohexanone ammoxidation, etc., and the by-product is water , is an environmentally friendly process, so it has attracted widespread attention. [0004] In the synthesis of TS-1, the main reason restricting its industrialization is its high synthesis cost, that is, ...

Claims

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Application Information

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IPC IPC(8): C01B39/08
Inventor 王祥生左轶郭新闻
Owner DALIAN UNIV OF TECH
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