CO_(2)氧化1-丁烯脱氢制1,3-丁二烯活性炭负载铁基催化剂的研究

Study on activated carbon supported iron-based catalysts for oxidative dehydrogenation of 1-butene to 1,3-butadiene with CO_(2)

采用CO_(2)为弱氧化剂进行1-丁烯氧化脱氢生产1,3-丁二烯可同时实现1-丁烯的高值转化及CO_(2)的有效利用,目前已经成为一种有潜力的生产工艺。为解决该工艺面临的选择性低的问题,研究了钾促进的活性炭负载铁基催化剂,考察了钾源和钾铁比对催化剂性能的影响。结果表明,以KNO3为钾源制备的钾铁物质的量比为0.5:9的催化剂表现出最佳的1,3-丁二烯选择性,高达69%。通过对不同钾源以及不同钾铁比改性的催化剂进行N2物理吸附/脱附、XRD、CO_(2)-TPD、NH3-TPD、TG等表征分析,发现催化剂表面的弱酸位是吸附和活化1-丁烯的活性中心;弱碱位不仅起到吸附与活化CO_(2)的作用,还对催化剂选择性的提高起到关键作用。钾助剂能提高催化剂的抗烧结能力,改变催化剂表面酸碱位,导致催化剂活性的差异。

Using CO_(2)as a soft oxidant for the oxidative dehydrogenation of 1-butene to produce 1,3-butadiene(BD)can simultaneously realize the high-value conversion of 1-butene and the effective utilization of CO_(2),which has become a potential production process.In order to solve the problem of low selectivity in this process,potassium promoted activated carbon supported iron-based catalyst was studied,and the effects of potassium source and potassium-iron ratio on the performance of the catalyst were investigated.The results showed that the catalyst with a potassium to iron molar ratio of 0.5:9 prepared by using KNO3 as the potassium source had the optimal selectivity to 1,3-butadiene,up to 69%.Through characterization of the catalysts by N2 physical adsorption and desorption,XRD,CO_(2)-TPD,NH_(3)-TPD and TG,it was found that the weak acid sites on the catalyst surface were the active centers for adsorption and activation of 1-butene,and the weak base sites not only played the role of adsorption and activation of CO_(2),but also played a key role in improving the selectivity.Potassium promoter could improve the anti-sintering ability of the catalyst and change the acid-base sites on the surface of the catalyst,resulting in the difference of catalyst activity.