Silicalite-1修饰的HY型分子筛及其对纤维素水解的催化性能

采用silicalite-1对HY型分子筛进行修饰,得到具有核壳结构的复合分子筛HY/silicalite-1。通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、N2的吸附-脱附及吡啶吸附红外(Py-FTIR)等手段对不同晶化时间合成的HY/silicalite-1复合分子筛进行了表征,研究了复合分子筛对纤维素水解的催化性能。结果表明,晶化时间直接影响复合分子筛的晶体生长规律和两组分的相对含量,最佳晶化时间为16-24 h,所得到的复合分子筛外貌呈核壳结构,silicalite-1附晶生长在HY型分子筛的表面;随着晶化时间的延长,复合分子筛的表面由胶浊状变为光滑,最终变为鳞片状;其B酸量先减少后增加,而L酸量则先增加后减少。其中,晶化时间为24 h的HY/silicalite-1复合分子筛B酸量最大,L酸量最小,对纤维素水解反应具有良好的催化性能,葡萄糖收率由HY型分子筛催化获得的28.0%大幅提高至45.8%。     

Synthesis of Colloidal Suspensions of Zeolite ZSM-2

Discrete colloidal particles of zeolite ZSM-2 with crystal sizes less than 100 nm, in the form of aqueous suspensions, have been synthesized in tetramethylammonium (TMA)-aluminosilicate solutions in the presence of either lithium or a combination of lithium and sodium hydroxide. The well-crystallized ZSM-2 has a specific surface area of 781 m²/g after purification and removal of the organic base by calcination. Synthesis times (t) are as short as 3 < t < 12 h and in certain cases, less than 3 h, less than those previously reported in the literature. Prolonged hydrothermal treatment of sols in the presence of sodium cations (>12 h) results in the phase transformation of ZSM-2 to the nitrogeneous edingtonite zeolite (Li,Na)-E. The synthesis of nitrogeneous (Li,Na)-E is also favored by a high TMA content in conjunction with sodium, whereas synthesis of zeolite N-A is favored by a high sodium content. Furthermore, it is shown that colloidal suspensions of TMA sodalite with crystal sizes less than 40 nm are synthesized in the absence of alkali cations.     

Cu-ZSM-5分子筛上[Cu-O-Cu]2+物种的原位红外光谱研究

通过原位监测Ｃｕ－ＺＳＭ－５分子筛的振动动红外光谱随温度及不同处理条件的变化情况,观察到［Ｃｕ－Ｏ－Ｃｕ］＾２＋物种的形成过程,即两个Ｃｕ（ＯＨ）＾＋在脱水过程中经二聚形成［Ｃｕ－Ｏ－Ｃｕ］＾２＋,低交换度样品开始产生［Ｃｕ－Ｏ－Ｃｕ］＾２＋物种所需脱水温度较高,通过观察不同处理条件对［Ｃｕ－Ｏ－Ｃｕ］＾２＋的影响,说明Ｃｕ＾２＋是通过脱出［Ｃｕ－Ｏ－Ｃｕ］＾２＋中的超各氧而被还原为Ｃｕ＾＋,较高     

改性ZSM—5分子筛在甲苯一段硝化中的应用

对ＮａＺＳＭ－５分子筛进行改性，在其表面引入铁，镁离子，用作硝硫混酸对甲苯一段硝化反应的催化剂，明显提高产物中对硝基甲苯的生成比例，研究了影响反应结果的因素。     

含硼MFI型分子筛膜制备与渗透汽化性能研究

采用二次生长法在廉价的多孔莫来石管状支撑体上合成了含硼MFI(B-MFI)分子筛膜。通过XRD、FTIR、ICP-AES、11BMAS NMR和SEM对形成膜和粉末进行表征,并考察了溶胶nB/nSiO2比、料液温度和浓度对分子筛膜渗透汽化性能的影响。表征结果证实BO4存在于MFI晶体骨架中。溶胶nB/nSiO2比对膜层微结构和渗透汽化性能有较大影响。B-MFI型分子筛膜选择性地从水溶液中透过有机物,在60℃、质量分数5%丙酮/水和乙醇/水体系的分离因子分别为260和70,均高于同等条件下制备的silicalite-1分子筛膜。     

The effects of alkali metal(Na+,K+) on the exchange degree of Hβ zeolite and the catalytic properties of the alkalized zeolites

The effects of alkali metals (Na+,K+) on the exchange degree of Hβ zeolite under different conditions and the conversion of α(or β)-methylnaphthalene over the alkalized zeolites were studied. The results showed that the H+ of Hβ zeolite is totally replaced by the Na+ of NaCl solution, while partially exchanged by the K+ of KC1 solution, there is an exchange equilibrium between the H+ and K+ for Hβ zeolite (Si/Al=17.23) and the value of equilibrium is 88.39. The exchange degree also increases with increasing the Si/Al of the samples. It was suggested that these resluts are attributed to the electrostatic field in the pore of Hβ zeolite and the nature of zeolite and the properties of alkali metal. The isomerization of α(or β)-methylnaphthalene is the main reaction over the samples and it is more favour on the proper acid-base sites of KHβ zeolite.     

甲苯甲醇侧链烷基化反应中沸石催化剂酸碱中心的作用Ⅱ．改性的X型和双组分改性的X／ZSM－5双沸石催化剂

制备了改性的ｘ型和ｘ／ＺＳＭ－５型沸石催化剂，并对其进行了评价和ＴＰＤ、ＥＳＣＡ表征，将实验结果进行了关联。结果表明，采用ＫＯＨ，Ｈ＿３ＢＯ＿３和碱土金属化合物等作为改性剂，可以调变沸石催化剂的酸碱中心，其中碱酸密度比为０．５３９的ＫＸ（Ｂ＿３）·ＫＺＳＭ－５（Ｃａ）催化剂，能显著提高甲苯、甲醇侧链烷基化制取苯乙烯反应的选择性和收率。井根据对实验结果的分析，初步探讨了甲苯、甲醇侧链烷基化反应的机理。     

甲苯甲醇侧链烷基化反应中沸石催化剂酸碱中心的作用Ⅰ．改性的X型、X／ZSM－5型和KX型沸石催化剂

甲苯甲醇侧链烷基化反应中沸石催化剂酸碱中心的作用Ⅰ．改性的Ｘ型、Ｘ／ＺＳＭ－５型和ＫＸ型沸石催化剂李永光，畅晋英，王建平（太原工业大学化工系，太原０３００２４）关链词沸石，侧链烷基化，甲苯，甲醇甲苯甲醇烷基化反应有两种方式：在苯环上烷基化生成二甲苯；...     

甲醇／丙烷在ZSM－5分子筛上偶合转化过程的研究

考察了甲醇／低碳烷烃在ＺＳＭ－５分子筛上偶合转化为芳烃和低碳烯烃的反应过程。对特定的催化体系，存在一最佳原料配比，使反应的热效应近似为零。偶合转化时甲醇完全转化，低碳烷烃的转化率低；不同催化剂上偶合转化产物分布差别极大，与ＨＺＳＭ－５相比，Ｇａ改性后可获得较高的芳烃和低碳烯烃收率。     

超临界反应条件下Y型分子筛催化剂失活的研究

对苯烷基化过程中Ｙ型分子筛催化剂的失活进行了多方面的实验研究。结果表明，超临界条件下该催化剂的活性寿命比液相条件下长达四倍以上，借助色－质谱联用机分析两种操作的反应产物，发现含有多环物质，并且它们的种类和数量随条件而不同。根据热力学原理，建立了多环物在超蚧流体中的溶解模型，并以并四苯，并五苯和并六苯作为焦前物模拟物进行了计算。