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本文进一步考察了载Ni丝光沸石的SiO_2/Al_2O_3比对二甲苯转化和产物分布的影响.结果表明,无论是载Ni或不载Ni丝光沸石上,邻二甲苯转化率随SiO_2/Al_2O_3增加而增加,SiO_2/Al_2O_3<20时,转化率明显增加,SiO_2/Al_2O_3>20时,递增缓慢,并趋于稳定.丝光沸石载Ni后,于氮气氛中进行二甲苯转化反应,总转化率降低,异构化产率基本不变,歧化产率略有降低,脱甲基化产率接近于零.表明浸渍Ni~(2+)形态对脱甲基化有抑制作用,Ni不是歧化反应的活性中心.在临氢条件下,Ni~0也没有抑制歧化反应的作用,Ni含量增加,二甲苯异构化产率基本不变.
The effect of SiO 2 / Al 2 O 3 conversion on xylene conversion and product distribution of Ni-loaded mordenite was further studied.The results showed that the conversion of ortho-xylene increased with the increase of SiO 2 / Al 2 O 3 in either Ni-loaded or Ni-free mordenite , The conversion rate increased obviously when SiO 2 / Al 2 O 3 was less than 20, and slowly increased and stabilized when SiO 2 / Al 2 O 3> 20. After the zeolite was loaded with Ni, xylene conversion reaction was carried out in nitrogen atmosphere, the total conversion decreased The yield of the disproportionation decreased slightly and the yield of demethylation was close to zero, indicating that the impregnation of Ni 2+ could inhibit demethylation and that Ni was not the active center of disproportionation reaction In the hydrogen condition, Ni ~ 0 also did not inhibit the disproportionation reaction, Ni content increased, xylene isomerization yield basically unchanged.