Department of Chemical Engineering, Faculty of Engineering, Ankara University, Ankara, 06100, Türkiye.
Department of Engineering, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom.
Environ Res. 2023 Jan 1;216(Pt 1):114479. doi: 10.1016/j.envres.2022.114479. Epub 2022 Oct 5.
A feasible and cost-effective process for utilization of toluene and heavy reformate is the conversion of its streams by transalkylation reaction into highly valuable xylenes. The process is usually catalysed by zeolites and the challenges to overcome in transalkylation of heavy reformate with toluene over zeolites are their selectivity, activity, long-term stability, and coke formation. Current study aimed to investigate xylenes production by transalkylation reaction on the synthesized metal-doped zeolite catalysts and to characterize prepared catalysts by FTIR, SEM, EDS and BET analysis. Toluene/heavy reformate modelled mixture was utilized as a feed. For the first time Beta and ZSM-5 catalysts with 10% (w/w) cerium and 0.1% (w/w) palladium were synthesized by calcination and wet impregnation method. Catalytic tests were performed by continuous-flow gas/solid catalytic fixed bed reactor at atmospheric pressure, 2 h and 5 h and 250, 300, 350 and 400 °C. Experimental results revealed that the highest heavy reformate conversion (98.94%) and toluene conversion (9.82%) were obtained over H-ZSM-5, at 400 °C and 2 h WHSV. The highest xylene selectivity (11.53) was achieved over H-ZSM-5, and the highest p-xylene percentage (62.40%), using Ce-ZSM-5 catalyst. ZSM-5 catalysts showed more resistance to coke deposition than Beta zeolites. The present study delivers novel approach and catalysts, which have immense potential for developing safer and inexpensive transalkylation process in industry.
利用甲苯和重重整料的可行且具有成本效益的方法是通过烷基转移反应将其转化为高价值的二甲苯。该过程通常由沸石催化，在沸石上用甲苯进行重重整料的烷基转移反应所面临的挑战是其选择性、活性、长期稳定性和积碳形成。本研究旨在研究合成的金属掺杂沸石催化剂上的二甲苯通过烷基转移反应的生产，并通过 FTIR、SEM、EDS 和 BET 分析对制备的催化剂进行表征。甲苯/重重整料模拟混合物用作进料。首次通过煅烧和湿法浸渍法合成了 10%（w/w）铈和 0.1%（w/w）钯的 Beta 和 ZSM-5 催化剂。在大气压、2 h 和 5 h 以及 250、300、350 和 400°C 的条件下，通过连续流动气/固催化固定床反应器进行了催化测试。实验结果表明，在 400°C 和 2 h WHSV 下，H-ZSM-5 上重重整料转化率（98.94%）和甲苯转化率（9.82%）最高。在 H-ZSM-5 上，二甲苯选择性最高（11.53），使用 Ce-ZSM-5 催化剂时，对二甲苯百分比最高（62.40%）。ZSM-5 催化剂比 Beta 沸石具有更强的抗积碳能力。本研究提供了一种新的方法和催化剂，为工业中开发更安全、更经济的烷基转移工艺提供了巨大的潜力。
