Ethylene Conversion to Higher Hydrocarbon over Copper Loaded BZSM-5 in the Presence of Oxygen

The successful production of higher hydrocarbons from methane depends on the stability or the oxidation rate of the intermediate products. The performances of the BZSM-5 and the modified BZSM-5 catalysts were tested for ethylene conversion into higher hydrocarbons. The catalytic experiments were carried out in a fixed-bed micro reactor at atmospheric pressure. The catalysts were characterized using XRD, NH3-TPD, and IR for their structure and acidity. The result suggests that BZSM-5 is a weak acid. The introduction of copper into BZSM-5 improved the acidity of BZSM-5. The conversion of ethylene toward higher hydrocarbons is dependent on the acidity of the catalyst. Only weaker acid site is required to convert ethylene to higher hydrocarbons. The loading of Cu on BZSM-5 improved the selectivity for higher hydrocarbons especially at low percentage. The reactivity of ethylene is dependent on the amount of acidity as well as the presence of metal on the catalyst surface. Cul%BZSM-5 is capable of converting ethylene to higher hydrocarbons. The balances between the metal and acid sites influence the performance of ethylene conversion and higher hydrocarbon selectivity. Higher loading of Cu leads to the formation of COx.

蒸气相合成BZSM-5沸石用于间二甲苯异构化反应

首次利用蒸气相法合成的BZSM-5沸石作为异构化催化剂,测定了BZSM-5沸石对间二甲苯异构化的活性和选择性。当B_2O_3/Al_2O_3(摩尔比)为1.8时异构化活性(50.97%)和选择性(20.86%)均达到较佳值。用IR、NH_(?)-TPD表征了BZSM-5沸石的酸强度及酸分布,同时与异构化活性和选择性进行了关联。实验结果表明,在合成中加入适量的硼有利于提高异构化活性和选择性。

异丁醛异构为甲乙酮的研究(I)

合成了不同硼含量的无铝分子筛BZSM-5,XRD及IR结果均表明,硼原于进入了分子筛骨架,由异丁醛异构化制甲乙酮的反应结果表明,BZSM-5具有较高的反应活性和甲乙酮选择性,较小的硼含量有利于保持适当的转化率和较高的选择性,BZSM-5对该反应的良好选择性,与其表面仅有弱酸中心而无强酸中心的这种酸性性质密切相关.

异丁醛异构为甲乙酮的研究(Ⅲ)

首次考察了在SAPO-5、SAPO-11、SAPO-34等磷酸硅铝分子筛及经磷改性的BZSM-5分子筛上异丁醛异构化的性能。在SAPO-11上,目的产物甲乙酮的选择性,与在BZSM-5上相近,可大于70％;BZSM-5经磷改性,异丁醛转化率无明显改变,而甲乙酮的选择性有较大提高,收率可达70％,SAPO-5及SAPO-34由于其孔道大小与反应物及目的产物分子大小不匹配,异丁醛转化率和甲乙酮选择性均甚低。

异丁醛异构为甲乙酮的研究(Ⅱ)

考察了在BZSM-5上引入数种离子后异丁醛反应活性及甲乙酮选择性的变化.Mg^(2+)、Cu^(2+)的引入,不同程度地降低了异丁醛的反应活性,提高了甲乙酮的选择性;而Ca^(2+)、La^(3-)的引入,则使反应活性升高,甲乙酮选择性降低.Sn^(2+)的引入对反应影响不明显.进一步用水蒸汽处理金属离子改性BZSM-5,其异丁醛反应性能也发生程度不等的变化.在多种催化剂上,甲乙酮的收率接近或超过65%.