Chemical Industry and Engineering Progress ›› 2023, Vol. 42 ›› Issue (7): 3561-3571.DOI: 10.16085/j.issn.1000-6613.2022-1629

• Industrial catalysis • Previous Articles     Next Articles

Solvent-free rapid synthesis of ZSM-12 zeolite

WANG Shuaiqi1,2(), WANG Congxin1, WANG Xuelin1,2, TIAN Zhijian1()   

  1. 1.Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-09-05 Revised:2022-10-24 Online:2023-08-14 Published:2023-07-15
  • Contact: TIAN Zhijian

无溶剂快速合成ZSM-12分子筛

王帅旗1,2(), 王从新1, 王学林1,2, 田志坚1()   

  1. 1.中国科学院大连化学物理研究所,辽宁 大连 116023
    2.中国科学院大学,北京 100049
  • 通讯作者: 田志坚
  • 作者简介:王帅旗(1993—),男,博士研究生,研究方向为分子筛合成。E-mail:wangshuaiqi@dicp.ac.cn
  • 基金资助:
    国家重点研发计划(2020YFB0606405)

Abstract:

A solvent-free rapid synthesis method of ZSM-12 zeolite was developed. The method consists of two steps. The first step was to prepare Si-Al precursor. Tetraethylorthosilicate, sodium aluminate, sodium fluoride, methanol and water were mixed and reacted for 3h under agitation at room temperature. After reaction, the liquid phase was evaporated, resulting in the Si-Al precursor. The second step involves the crystallization of Si-Al precursor. The Si-Al precursor was mixed with seeds and tetraethylammonium hydroxide, and subsequently transferred to autoclave for crystallization for 24h at 160℃ to obtain the ZSM-12 zeolite. The crystallization of ZSM-12 zeolite was faster in solvent-free synthesis system than in hydrothermal synthesis system. By using XRD, SEM, solid-state NMR, TG, and FTIR characterizations, the physicochemical properties of Si-Al precursor were analyzed, and the crystallization process of ZSM-12 zeolite was investigated. The results showed that the rapid crystallization was attributed to the addition of seeds and the formation of Si—O—Al in advance in Si-Al precursor. The seeds provided surface for the crystallization of ZSM-12 zeolite, thereby shortening the induction period. The formation of Si—O—Al bonds in the Si-Al precursor promoted structural rearrangement, and shortened the growth period.

Key words: solvent-free method, rapid synthesis, ZSM-12 zeolite, seeds, Si-Al precursor

摘要:

开发出一种无溶剂快速合成ZSM-12分子筛的方法。该方法分为两步。第一步是硅铝前体的制备:将正硅酸乙酯、铝酸钠、氟化钠、甲醇、水混合,在室温搅拌条件下反应3h后蒸干液体,得到硅铝前体。第二步是硅铝前体的晶化:将硅铝前体与晶种、四乙基氢氧化铵模板剂混合均匀后,移入反应釜中,在160℃条件下晶化24h得到ZSM-12分子筛产品。相比于已有的ZSM-12分子筛水热过程,无溶剂合成过程的晶化时间大大缩短。采用XRD、SEM、solid-state NMR、TG、FTIR等手段分析了硅铝前体的物化性质,跟踪了ZSM-12分子筛的晶化过程。结果表明,晶种的加入和硅铝前体中Si—O—Al键的提前构筑是ZSM-12分子筛快速晶化的原因。晶种为ZSM-12分子筛的生长提供表面,缩短诱导期;硅铝前体中Si—O—Al键的提前构筑促进结构重排,从而缩短生长期。

关键词: 无溶剂法, 快速合成, ZSM-12分子筛, 晶种, 硅铝前体

CLC Number: 

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