非缓冲体系中草酸对超稳Y型分子筛的化学改性催化剂的制备与表征

将草酸作为化学改性剂，对超稳Ｙ型分子筛（ＵＳＹ）进行了化学改性。在非缓冲体系中，草酸溶液的加入量、溶剂用量、反应时间及ｐＨ值等条件对ＵＳＹ分子筛脱铝改性后的晶体结构有一定影响。采用ＸＲＤ对改性后的ＵＳＹ分子筛的结构进行了分析，并与反应条件相关联得出了催化剂的最佳制备条件。研究结果表明，改性后的ＵＳＹ分子筛的硅铝比、晶胞常数和结晶硅含量等都有明显的改善，这说明草酸对ＵＳＹ分子筛的脱铝改性是可行的。

/MODIFICATION OF USY ZEOLITE BY USING OXALIC ACID IN UNBUFFERED SYSTEM/

The conditions of USY dealumination with oxalic acid in unbuffered system were tentatively investigated by changing the additional amounts of oxalic acid and HNO 3 solvent, reaction time, pH value of the solution. The structure parameters of the modified samples are characterized by XRD technique. The results of the study show that the optimization of the dealumination of USY with oxalic acid in the moderate unbuffered system may result in an industrial process of the synthesis of FCC catalysts for the production of light olefins. Though the crystallinity of the modified sample was partially collapsed in the course of the treatment, the ratio of Si to Al reached about 10.5 and unit cell size decreased from 2.4528 nm to 2.4460 nm. The pH value and the amount of oxalic acid solution have a great influence on the modification of the USY samples, while the reaction time and the amount of solvent have a little effect on it. This is of benefit to increase the octane number of gasoline and the amount of gasoline.