摘要
采用红外光谱、程序升温脱附、原子吸收光谱、等离子光谱、Hammett指示剂非水滴定和催化活性测试等方法研究了经不同浓度的KOH溶液交换得到的(K,Na)ZSM-5的酸碱性质。结果表明,(K,Na)ZSM-5具有中等强度的L酸位(K^+,Na^+)及弱碱位(AlO_4^-或骨架O^(2-))和强碱位(OH^-).KOH浓度增大.酸性减弱,碱性增强.所得(K,Na)ZSM-5具有较高的异丙醇脱氢、脱水活性.催化性能与酸碱性密切相关.
The acid-base properties of a series of (K,Na)ZSM-5 zeolites with various contents K were investigated by IR,TPD,Hammett-Indicator non-aqueous titration and measurement of catalytic properties.The KOH exchanged ZSM-5 zeolites have moderate Lewis acid sites(cation,Na+,K+) and two different kinds of base sites,the weak ones (AlO4-or framework oxygen ions) and the strong ones(OH-).The acidity decreases while the basicity increases with increasing the concentrations of exchanging KOH solutions.The samples exhibit higher catalytic activities for the dehydrogenation and dehydration of isopropanol.The catalytic properties correlate well with the acid-base properties.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1992年第10期1274-1278,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
国家教育委员会博士点基金
关键词
分子筛
酸碱性质
催化性能
ZSM-5
(K,Na)ZSM-5 zeolite,Acid-base properties,Catalytic activities
