基于离子液体及固体酸优势的新型异丁烷烷基化催化剂的设计与研究

The project attempts to synthesize a novel catalyst for isobutane-olefins alkylation reaction. The preparation of the catalyst will combine the advantages of ionic liquids and solid acids. The novel catalyst have high activity with little corrosivity, and can be regenerated with many times. The regeneration of ionic liquids in the alkylation process is relatively difficult and the ionic liquid alkylation often leads to equipment corrosion. These problems may be solved by supporting the ionic liquid on the solid acid. Some bottleneck problems of solid acid alkylation, such as the low conversion of butenes, carbon deposition on solid acids, may be reduced by using new ionic liquid/solid acid catalysts. The effects of the catalyst composition on oligomerization and H-transfer reactions can be detected through the deuterium tracer and online analysis. By means of acidity measurement and the structural analysis, the deactivation of the catalysts will be better understood. The efficient regeneration method of novel catalysts can be determined by optimizing the composition of the catalysts and the reaction conditions. According to these studies, the alkylation reaction mechanism of the ionic liquid/solid acid catalysts will be depicted. The project will help to resolve some bottlenecks of the present alkylation processes. Moreover, it may provide some of the basic data and theoretical supports for the commercial application, and then promote the development of the alkylation catalysts.

本项目试图结合离子液体与固体酸各自优势，设计制备温和高效、腐蚀污染小、可循环再生的新型异丁烷烷基化催化剂。通过固体酸负载离子液体等方法，期望解决离子液体烷基化过程中，催化剂再生相对困难、易产生污染腐蚀等问题；同时也希望克服固体酸烷基化中丁烯转化率低、“积碳”较多等制约其应用的关键障碍。通过氘代试剂示踪、在线仪器分析等手段，确定新型催化剂组成对丁烯低聚、氢转移等关键反应的影响；通过酸性度量、连续烷基化、结构分析等方法，综合探讨液固组成、反应条件等对催化剂失活的影响；通过采取催化剂组成改性，优化再生反应条件等措施，最终确定温和高效的再生方法。同时根据以上研究，刻画离子液体/固体酸新型催化剂的烷基化反应历程。本项目的研究工作将有助于解决以往催化剂在进行烷基化反应时所遇到的某些瓶颈问题，为烷基化实践提供一些基础数据和理论支持，以利于异丁烷烷基化催化剂的研究与应用的发展。

本项目首先设计合成了一类新型的离子液体/固体酸异丁烷烷基化催化剂。新型催化剂结合了离子液体（IL）和固体酸（SA）的优点，通过将硫酸/氧化锆（SZ）分散到介孔MCM-41中并固定离子液体在载体上而得到IL/SA催化剂。在间歇和连续搅拌釜式反应器（CSTR）中分别研究了新型IL/SA催化剂的催化性能，5g IL/SA可以连续催化烷基化反应超过240分钟，烷基化产物中三甲基戊烷和辛烷值分别达到83.3 wt%和98.5。第二，通过氘代试剂示踪、量子化学计算、分子动力学模拟等手段，我们确定了离子液体类催化剂对丁烯低聚、氢转移等关键反应的影响；深入探讨了催化组成在烷基化过程中的界面行为。第三，通过实验手段，建立了基于古特曼受体数的Lewis液体酸的酸度测量方法；通过FT-IR以及AIMD模拟方法对IL/SA催化剂酸量进行了定性和定量研究；第四，通过静态混合器，连续反应器确定了离子液体以及IL/SA催化剂的烷基化反应动力学常数，建立了新型烷基化催化剂的反应动力学模型，刻画了新型催化剂的烷基化历程。通过本项目的实施，拓展了烷基化催化剂的合成设计思路，更深入地理解了新型催化剂中的烷基化反应关键因素，为新烷基化技术的研究与应用提供了有益的实践和理论支撑。