摘要
H-MOR分子筛是目前已发现的分子筛类催化剂中最具活性和选择性的二甲醚羰基化反应催化剂。在实际工业应用中,H-MOR分子筛往往不可避免地发生脱铝现象,导致分子筛Bronsted酸量降低,从而降低分子筛的二甲醚羰基化反应活性。通过一维和二维固体核磁共振实验研究了高温(700℃)、不同水蒸气处理时间下H-MOR分子筛的物化性质及骨架铝的稳定性。随着水蒸气处理时间的增加,H-MOR分子筛脱铝程度加剧,Bronsted酸量下降。H-MOR存在四配位铝物种Al(Ⅳ)-1、Al(Ⅵ)-2及六配位铝物种Al(Ⅵ)。高温水蒸气处理后,出现新的铝物种Al(Ⅴ)信号。H-MOR在经过水蒸气处理后,骨架四配位铝物种Al(Ⅳ)-1先转变为扭曲四配位铝物种Al(Ⅳ)-2,接着转变为五配位铝物种Al(Ⅴ)和六配位铝物种Al(Ⅵ),进一步转变为铝的氧化物。
H-MOR zeolite is the most active and selective catalyst for the carbonylation of dimethyl ether among the zeolite catalysts that have been found so far.In practical industrial applications,the dealumination of H-MOR zeolites is inevitable in most cases,which results in a decrease in Br nsted acid amount,thus reducing the dimethyl ether activity of zeolites.The physical and chemical properties of H-MOR zeolite and the stability of framework aluminum were investigated by 1D and 2D solid-state nuclear magnetic resonance(NMR)experiments at high temperature(700℃)and different steam treatment time.With the increase of steam treatment time,the dealumination degree of H-MOR zeolite was intensified,and the Br nsted acid amount decreased.There are tetra-coordinated aluminum species Al(Ⅳ)-1 and Al(Ⅵ)-2 and hexa-coordinated aluminum species Al(Ⅵ)in H-MOR.After high temperature steam treatment,new aluminum species Al(Ⅴ)signals appear.After H-MOR is treated with steam,the framework tetra-coordinated aluminum species Al(Ⅳ)-1 is first transformed into twisted tetra-coordinated aluminum species Al(Ⅳ)-2,then into the penta-coordinated aluminum species Al(Ⅴ)and hexa-coordinated aluminum species Al(Ⅵ),and further into oxides of aluminum.
作者
刘冲
徐舒涛
魏迎旭
刘中民
LIU Chong;XU Shutao;WEI Yingxu;LIU Zhongmin(National Engineering Research Center for Low Carbon Catalytic Technology,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2023年第6期1231-1241,共11页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家自然科学基金项目(21972142,22022202,22241801,21991092,21991090,22288101)
大连市杰出青年基金项目(2021RJ01)
中国科学院先导专项(XDA21030200)资助。
关键词
H-MOR
固体核磁共振
水蒸气处理
骨架铝
稳定性
H-MOR
solid-state nuclear magnetic resonance(NMR)
steam treatment
framework aluminum
stability
