甲醇气相羰基化Ni-Pd/AC催化剂失活机理的研究

采用连续流动固定床反应装置，Ni Pd/AC为催化剂，在260℃、1.5MPa、CO/CH3OH/CH3I摩尔比为20/19/1、W/F为7.5g·h·mol－1下考察了催化剂的稳定性，并对失活前、后Ni-Pd/AC催化剂进行了比表面积、热解-红外分析（Py FTIR）和XPS表征。结果表明,反应初期反应产物乙酸或乙酸甲酯与催化剂之间强吸附堵塞了催化剂孔道，导致扩散受到限制。随着反应时间的延长，羰基化活性中心Ni不断迁移并富集在催化剂表面上，使Ni晶粒增大，成为积炭的活性中心，积炭堵塞了催化剂孔道，导致催化剂失活。进一步对积炭类型进行研究，发现形成的碳物种主要是类石墨型碳。

Deactivation of activated carbon supported nickel-palladium catalyst for vapor phase carbonylation of methanol

Vapor phase carbonylation of methanol was investigated over Ni-Pd/AC catalyst under the conditions of 260°C, 1.5 MPa, CO/CH₃OH/CH₃I(molar ratio)20/19/1, W/F=7.5 g_cat·h·mol⁻¹. The structure and surface property of the fresh and deactivated Ni-Pd/AC catalysts were characterized by BET specific surface area, Pyrolysis-FTIR (Py-FTIR) and XPS. It was found that the deactivation at the primary step appeared to be consistent with a strong adsorption of reaction products that plugged the catalyst pores and led to a diffusion limitation. With the proceeding of the reaction, the carbonylation active site Ni migrated gradually and enriched on the catalyst surface, resulting in easy carbon deposition, which enhanced the deactivation of the catalyst. Further investigation revealed that the carbon deposited on the catalyst surface has graphite structure or is similar to graphite structure.