沸石骨架脱羟与脱铝数量之间关系的NMR研究

本文讨论了用小板例角脉冲技术测试具有半整数自旋四极核＾２７Ａｌ和ＮＭＲ谱。通过ＮａＣｌ反交换测量不同温度焙烧的ＨＺＳＭ－５，ＨＭ，ＨＦＵ－９和Ｈ－镁碱沸石Ｂ酸位的变化以及用ＥＰＲ测试Ｌ酸位变化，发现在５００～７００℃温域四种沸石各自有一个脱羟的空变温区。用小板倒角脉冲＾２７ＡｌＮＭＲ技术观察到这些样品仅有少量非骨架铝，从而确定了四种分子筛脱羟与脱铝是不同步的。

NMR INVESTIGATION OF RELATION BETWEEN THE AMOUNT OF DEHYDROXYLATION AND DEALUMINATION ON THE FRAMEWORK OF FOUR SPECIES ZEOLITES

mall flip angle pulse NOR technique of nuclei with half integerspin in powdered sample was discussed.A series of HZSM-5,HM,HFu-9 and H--Ferrierite samples was calcinated at different temperatures.The change of the amount of B acid sites of zeolites was determined by inverse exchange with NaCI solution and i-acid sites weremeasured by EPR spectroscopy after adsorption of benzene vapor.Itwas found that during the calcination the B acid sites were transformedinto the l-acid sites and there was a sudden change. Zeolite sampleswhich had been calcined at different teml>eratures were then impregnated with a solution of 38% vol. acetylacetone in ethanol and observed insmall flip angle pulse 27Al MAS NMR. only a few nonframework aluminum were existed in those calcined samples according'to the 27AlNMR observation to provide that the dehydroxyl process and the formation of L acids for HZSM-5,Ha,HFu-9,H-Ferrierite would not accompany simultaneously with the dealumination process.