NH_(4)^(+)-TPA^(+)-SiO_(2)-Al_(2)O_(3)-H_(2)O体系中ZSM-5沸石分子筛合成的研究

ASTUDY ON THE SYNTHESIS OF ZEOLITE ZSM-5 IN THE SYSTEM OF NH_(4)^(+)-TPA^(+)-SiO_(2)-Al_(2)O_(3)-H_(2)O

七十年代初期美国Mobil公司首先研究成功的ZSM-5沸石分子筛,由于它具有独特的孔道结构,对烷基化,异构化,选择裂化和甲醇合成汽油等反应具有独特的催化性能,目前已成为被普遍重视的新型催化剂材料。通常合成HZSM-5沸石分子筛,都是在TAA-Na_(2)O-SiO_(2)-Al_(2)O_(3)-H_(2)O体系中进行的,首先制得NaZSM-5沸石分.

Zeolite HZSM-5 has been found to possess excellent quality as a catalyst.It can usually be prepared by exchange reaction between HC1 or NH_(4) Cl and NaZSM-5.The product Thus obtained is HZSM-5 or NH_(4)ZSM-5 respectively;the latter is capable of being transformed into HZSM-5 by heating.We report here a new procedure for synthesis of Zeolite HZSM-5.The NH_(4) ZSM-5 is prepared in the systems of NH_(4)^(+)-tetrapropylamonium bromide without the presence of NaOH and reaction of ion exchange.The reaction temperature from 1.00℃to 160℃is good enough for the synthesis of NH_(4) ZSM-5;the range of SiO_(2) /Al_(2)O_(3) ratio of the product is from 52to 180.The lower mole limit of TPABr used is 0.02 mole.The thermal stability of the product is good.It is shown by curves of TGA and DTA that there is no phase transform peak in the range of temperature up to 1200℃.Its scanning electron micrographs,X-ray diffraction patterrn and the results of adsorption measurement are given.