采用二次合成法制备了含氮MCM-41分子筛,系统考察了氨气流速、氮化温度和氮化时间等因素对分子筛氮含量的影响,并通过X射线衍射、N2吸附、透射电镜、X射线光电子能谱和29Si MAS NMR等方法探测了氮化后分子筛的物理化学特性.结果表明,氨...采用二次合成法制备了含氮MCM-41分子筛,系统考察了氨气流速、氮化温度和氮化时间等因素对分子筛氮含量的影响,并通过X射线衍射、N2吸附、透射电镜、X射线光电子能谱和29Si MAS NMR等方法探测了氮化后分子筛的物理化学特性.结果表明,氨气流速和氮化温度是影响分子筛氮含量的主要因素.氨气流速为400ml/min时,950℃下经12h氮化后的MCM-41分子筛氮含量(质量分数)可达26·0%,并较好地保持了原有分子筛的骨架结构.由于氮化温度相对较低,对分子筛的结构破坏较小,而氮含量高、氮化后的MCM-41分子筛对Knoevenagal缩合反应具有很高的碱催化活性.展开更多
Grafted fibrous polymer with quaternary amine groups could function as a highly-efficient catalyst for biodiesel fuel (BDF) production. In this study, the optimization of grafted fibrous polymer (catalyst) and transes...Grafted fibrous polymer with quaternary amine groups could function as a highly-efficient catalyst for biodiesel fuel (BDF) production. In this study, the optimization of grafted fibrous polymer (catalyst) and transesterification conditions for the effective BDF production was attempted through a batch-wise transesterification of triglyceride (TG) with ethanol (EtOH) in the presence of a cosolvent. Trimethylamine was the optimal quaternary amine group for the grafted fibrous catalyst. The optimal degree of grafting of the grafted fibrous catalyst was greater than 170%. The optimal transesterification conditions were as follows: The optimal molar quantity of quaternary amine groups, transesterification temperature, molar ratio of TG and EtOH, and primary alkyl alcohol were 0.8 mmol, 80°C, 1:200, and 1-pentanol, respectively. The grafted fibrous catalyst could be applied to BDF production using natural oils. Furthermore, the grafted fibrous catalyst could be used repeatedly after regeneration involving three sequential processes, i.e., organic acid, alkali, and alcohol treatments, without any significant loss of catalytic activity.展开更多
文摘采用二次合成法制备了含氮MCM-41分子筛,系统考察了氨气流速、氮化温度和氮化时间等因素对分子筛氮含量的影响,并通过X射线衍射、N2吸附、透射电镜、X射线光电子能谱和29Si MAS NMR等方法探测了氮化后分子筛的物理化学特性.结果表明,氨气流速和氮化温度是影响分子筛氮含量的主要因素.氨气流速为400ml/min时,950℃下经12h氮化后的MCM-41分子筛氮含量(质量分数)可达26·0%,并较好地保持了原有分子筛的骨架结构.由于氮化温度相对较低,对分子筛的结构破坏较小,而氮含量高、氮化后的MCM-41分子筛对Knoevenagal缩合反应具有很高的碱催化活性.
文摘Grafted fibrous polymer with quaternary amine groups could function as a highly-efficient catalyst for biodiesel fuel (BDF) production. In this study, the optimization of grafted fibrous polymer (catalyst) and transesterification conditions for the effective BDF production was attempted through a batch-wise transesterification of triglyceride (TG) with ethanol (EtOH) in the presence of a cosolvent. Trimethylamine was the optimal quaternary amine group for the grafted fibrous catalyst. The optimal degree of grafting of the grafted fibrous catalyst was greater than 170%. The optimal transesterification conditions were as follows: The optimal molar quantity of quaternary amine groups, transesterification temperature, molar ratio of TG and EtOH, and primary alkyl alcohol were 0.8 mmol, 80°C, 1:200, and 1-pentanol, respectively. The grafted fibrous catalyst could be applied to BDF production using natural oils. Furthermore, the grafted fibrous catalyst could be used repeatedly after regeneration involving three sequential processes, i.e., organic acid, alkali, and alcohol treatments, without any significant loss of catalytic activity.
