CAJ | 학술논문

采用同晶置换方法制备了系列氟硅酸铵改性的HZSM-12分子筛.对改性前后的分子筛进行了XRD、NH_3-TPD、Py-IR、N_2物理吸附等表征,并在固定床微型反应实验装置上考察了它们对萘与甲醇烷基化反应合成2,6-二甲基萘的催化性能.结果表明,氟硅酸铵改性提高了HZSM-12分子筛的结晶度,在分子筛晶格中产生了二次介孔,增大了分子筛的介孔孔容和总孔容,有效地改变了分子筛的酸量及酸强度分布.经适宜浓度的氟硅酸铵水溶液改性后,HZSM-12分子筛对萘与甲醇烷基化反应的催化性能得到明显改善,在保持良好催化活性的基础上有效地提高了2,6-DMN的选择性及2,6-DMN/2,7-DMN摩尔比,反应6 h后2,6-DMN的选择性和2,6-DMN/2,7-DMN摩尔比分别为26%和1.93.
채용동정치환방법제비료계렬불규산안개성적HZSM-12분자사.대개성전후적분자사진행료XRD、NH_3-TPD、Py-IR、N_2물리흡부등표정,병재고정상미형반응실험장치상고찰료타문대내여갑순완기화반응합성2,6-이갑기내적최화성능.결과표명,불규산안개성제고료HZSM-12분자사적결정도,재분자사정격중산생료이차개공,증대료분자사적개공공용화총공용,유효지개변료분자사적산량급산강도분포.경괄의농도적불규산안수용액개성후,HZSM-12분자사대내여갑순완기화반응적최화성능득도명현개선,재보지량호최화활성적기출상유효지제고료2,6-DMN적선택성급2,6-DMN/2,7-DMN마이비,반응6 h후2,6-DMN적선택성화2,6-DMN/2,7-DMN마이비분별위26%화1.93.
A series of (NH_4)_2SiF_6-modified HZSM-12 catalysts were prepared by isomorphous substitution, and characterized by X-ray diffraction, temperature-programmed desorption of ammonia, FT-IR spectroscopy of adsorbed pyridine, N_2-adsorption. Their catalytic performance for synthesis of 2,6-dimethylnaphthalene in a fixed-bed reactor by methylation of naphthalene with methanol was also investigated. The results showed that through (NH_4)_2SiF_6-modification the crystallinity of HZSM-12 zeolite was increased, mesopore volume and total pore volume were enlarged due to the presence of secondary mesoporous, total acidity and distribution of acid strength were effectively altered. The catalytic performance of HZSM-12 for the methylation of naphthalene with methanol was improved by modification of (NH_4)_2SiF_6 with optimum concentration. An obvious increase of selectivity to 2, 6-DMN and 2,6-DMN/2,7-DMN molar ratio were observed on the premise that catalytic activity of (NH_4)_2 SiF_6-modified HZSM-12 was similar to that of HZSM-12. After 6 h methylation of naphthalene with methanol, 2,6-DMN selectivity of 26 % and 2,6-DMN/2,7-DMN molar ratio of 1.93 were obtained.