气相法磷改性对USY沸石酸性及其水热稳定性的调控  

Improvement of the Acidity and Hydrothermal Stability of USY Zeolite by Phosphorus Modification Using Gas-phase Method

作　　者：张强[1,2,3] 赵红娟 李蕊 王久江[3,4] 翟敏慧 马跃 夏添[1,2,3] 曾鹏晖 任申勇[1,2,3] 刘宏海 高雄厚 徐春明[1,2,3] 申宝剑 ZHANG Qiang;ZHAO Hong-juan;LI Rui;WANG Jiu-jiang;ZHAI Min-hui;MA Yue;XIA Tian;ZENG Peng-hui;REN Shen-yong;LIU Hong-hai;GAO Xiong-hou;XU Chun-ming;SHEN Bao-jian(College of Chemical Engineering and Environment,China University of Petroleum,Beijing 102249,China;State Key Laboratory of Heavy Oil Processing,Beijing 102249,China;The Key Laboratory of Catalysis of CNPC,Beijing 102249,China;Lanzhou Petrochemical Research Center,Petrochemical Research Institute,PetroChina Company Limited,Lanzhou 730060,China)

机构地区：[1]中国石油大学(北京)化学工程与环境学院,北京102249 [2]重质油全国重点实验室,北京102249 [3]CNPC催化重点实验室,北京102249 [4]中国石油天然气股份有限公司石油化工研究院兰州化工研究中心,甘肃兰州730060

出　　处：《分子催化（中英文）》2024年第4期317-330,共14页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金创新研究群体项目(22021004);中国石油科研项目(2022ZG16)。

摘　　要：磷(P)改性是提高沸石催化剂稳定性的有效方法之一.我们考察了三氯化磷(PCl_(3))气相法和磷酸氢二铵浸渍法制备得到的不同P改性USY样品.研究发现,2种P改性方法制备的样品中P物种均能够与USY中的Si―OH发生相互作用,同时夺取附近的非骨架Al物种,将表现为L酸的Si―O(EFAl)―Al转变成显示强B酸的Si―OH―Al.非骨架Al的迁移改善了沸石的孔径分布.在600℃水热老化后发现,气相法PCl_(3)改性后样品的桥羟基没有被破坏,其原因是PCl_(3)改性后样品的P物种主要为低聚态P物种,能够更好地与附近的四配位骨架Al发生相互作用,从而保护沸石的桥羟基不被破坏.而浸渍法磷酸氢二铵改性后样品主要生成高聚态P物种,与附近的四配位骨架Al发生相互作用能力弱,保护沸石桥羟基的作用不强.因此,气相法PCl_(3)改性样品在600℃水热老化4 h后的强B酸酸量(41μmol·g^(-1))明显高于浸渍法P改性样品(21μmol·g^(-1)).在800和900℃水热老化4 h后,PCl_(3)改性样品较浸渍法P改性样品和未改性样品展现了更高的结晶保留度,结合正辛烷催化裂化反应数据,表明气相法PCl_(3)改性后的USY样品具有更高的催化活性稳定性和结构稳定性.P modification is an effective method to improve the stability of zeolite catalysts.This article discusses the differences between different P-modified USY zeolites prepared by the PCl_(3) gas-solid reaction method and the conventional(NH4)2HPO4 impregnation method.The study found that the P species of the two P modification methods can interact with the Si―OH in USY,and at the same time capture the nearby non-framework Al species,converting the L acidic(Si―O(EFAl)―Al)into a strong B acid Si―OH―Al.The migration of non-framework Al improves the pore size distribution of zeolite.After hydrothermal aging at 600℃,it was found that the zeolite bridge hydroxyl group of the PCl_(3)-modified sample was not destroyed.The reason is that the P species of the PCl_(3)-modified sample was mainly an oligomeric P species,which can better interact with nearby the four-coordinated framework Al interacts to protect the bridge hydroxyl groups of the zeolite.The sample prepared by the impregnation method mainly generates higher polymer P species,which weakly interacts with the nearby four-coordinated framework Al,resulting in little protection for the bridge hydroxyl groups of the zeolite.Therefore,the amount of strong B acid(41μmol·g^(-1))of the PCl_(3) modified sample by the gas phase method was significantly higher than that of the P-modified sample by the impregnation method(21μmol·g^(-1))after hydrothermal aging at 600℃ for 4 h.After hydrothermal aging at 800 and 900℃ for 4 h,the PCl_(3) modified samples exhibited higher crystallinity retention compared to the impregnation method modified samples and the unmodified samples,combined with the fact that the PCl_(3)-modified sample has the highest n-octane catalytic cracking reaction activity after hydrothermal aging at 600℃ for 4 h,all results show that the USY sample modified by gas phase PCl_(3) has higher catalytic activity stability and structural stability.

关 键 词：USY沸石 气相法磷改性 酸性改善 水热稳定性 

分 类 号：O643.32[理学—物理化学]