应用化学

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开放骨架磷酸铝合成中碳链长度对乙二胺结构导向效应的影响

常晓文,鲁婷婷,魏颖真,郭明玥,闫文付(),徐如人   

  1. 吉林大学化学学院,无机合成与制备化学国家重点实验室 长春 130012
  • 收稿日期:2018-04-16 出版日期:2018-09-01
  • 通讯作者: 闫文付
  • 基金资助:
    国家自然科学基金(21571075,21320102001,21621001)国家重大研发计划(2016YFB0701100)高等学校学科创新引智计划(B17020)和吉林大学高层次科技创新团队项目资助

Influence of Carbon Chain Length on the Structure-Directing Effect of Ethylenediamine in the Synthesis of Open-Framework Aluminophosphates

CHANG Xiaowen,LU Tingting,WEI Yingzhen,GUO Mingyue,YAN Wenfu(),XU Ruren   

  1. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry,Jilin University,Changchun 130012,China
  • Received:2018-04-16 Published:2018-09-01
  • Contact: YAN Wenfu
  • Supported by:
    Supported by the National Natural Science Foundation of China(No.21571075, No.21320102001, No.21621001), the National Key Research and Development Program of China(No.2016YFB0701100), the 111 Project(No.B17020), Program for JLU Science and Technology Innovative Research Team

摘要:

以乙二胺(EDA)和1,3-丙二胺(1,3-DAP)为结构导向剂,在180 ℃加热摩尔比n(Al2O3):n(P2O5):n(R):n(H2O)=1:1:1:277(R=EDA,1,3-DAP)的混合物,分别得到了高结晶度的三维阴离子开放骨架磷酸铝AlPO4-12和UiO-26。 利用X射线粉末衍射分析、元素分析和液相酸碱度测量等表征手段,研究了两个合成体系的晶化过程以及晶化过程中液相的Al、P浓度和pH值随时间的演化。 用Materials Studio中的“原子体积和表面”模块和Dmol3模块计算了双质子化乙二胺和1,3-丙二胺的体积以及Hirshfeld电荷。 结果表明,双质子化EDA和1,3-DAP中N原子上的Hirshfeld电荷分别为0.073 e和0.064 e,按Hirshfeld电荷计算的电荷密度分别为1.8573和1.3400 e/nm3,按形式电荷计算的电荷密度分别为25.44和20.94 e/nm3,而AlPO4-12和UiO-26的骨架电荷密度分别为-6.1和-4.6 e/nm3。 结果表明,与氨基中N原子相连碳链长度的改变会影响其上的电荷量以及电荷密度,从而改变原有机胺的结构导向效应,导致晶化产物从AlPO4-12变成了具有较小电荷密度的UiO-26。

关键词: 沸石, 磷酸铝, 结构导向效应, 电荷量, 电荷密度

Abstract:

By heating the initial mixture with the molar ratio of n(Al2O3):n(P2O5):n(R):n(H2O)=1:1:1:277(R=ethylenediamine(EDA) or 1,3-propanediamine(1,3-DAP)) at 180 ℃, a highly crystalline three-dimensional anionic open-framework aluminophosphate of AlPO4-12 or UiO-26 was obtained. The crystallization processes of both initial mixtures were investigated by X-ray diffraction analysis(XRD), elemental analysis, and pH measurement. The volume and the Hirshfeld charge on the N atom of the diprotonated EDA and 1,3-DAP were calculated by the “atom volume and surface” module and the Dmol3 module in Materials Studio, respectively. Theoretical calculation shows that the charge on the N atom of diprotonated EDA or 1,3-DAP is 0.073 e and 0.064 e(Hirshfeld), respectively. The corresponding charge density is 1.8573 and 1.3400 e/nm3(Hirshfeld). The corresponding formal charge density is 25.44 and 20.94 e/nm3, respectively. The framework charge density of AlPO4-12 and UiO-26 is -6.1 e/nm3 and -4.6 e/nm3, respectively. These results indicate that the change in the length of carbon-chain connected to the N atom in the amino group can affect the amount of charge and the charge density on it, which accordingly affects its initial structure-directing ability, resulting the crystallization product changed from AlPO4-12 to UiO-26 with a smaller charge density.

Key words: zeolite, aluminophosphate, structure-directing effect, charge, charge density