The poisoning of noble metal catalysts by phosphorus compounds—I chemical processes, mechanisms and changes in the catalyst
The poisoning of noble metal catalysts by phosphorus compounds—I chemical processes, mechanisms and changes in the catalyst
复制标题
DOI：
10.1016/0009-2509(80)85031-7
复制
发表时间：
1980
影响因子：
4.7
通讯作者：
B. Angele;K. Kirchner
中科院分区：
文献类型：
--
作者：
B. Angele;K. Kirchner
贵金属载体催化剂在氧化条件下被磷的中毒由两部分组成：“可逆”部分，其是由于金属和载体的表面被五氧化二磷玻璃或缩合的高级磷酸物理覆盖，以及另一不可逆部分，其是由于载体物质（Al 2O3、SiO2）与磷酸盐的毒物的化学反应。来自该过程可逆部分的沉积物可以通过用水洗涤或在无毒气流中加热和升华来去除。1. (1)用P4O10或多聚磷酸涂层覆盖贵金属和载体的表面。由于这些涂层可以通过简单的方法去除，这被描述为磷中毒过程的“可逆”部分。(2)在这里考虑的系统中普遍存在的高温下，磷可以与常规载体材料发生不可逆反应，形成磷酸盐和混合氧化物。以这种方式，大量的磷可以沉积在催化剂中，这导致孔的堵塞和贵金属微晶的夹杂。磷的这方面行为是典型的非选择性催化剂毒物，包括Si、As、Pb、Zn和其它重金属。催化剂中毒过程、中毒动力学和磷在整个催化剂中的分布在下面的文献[4]中描述。
The poisoning of noble metal carrier catalysts by phosphorus under oxidizing conditions consists of two parts: a “reversible” part which is due to physical coverage of the surface of the metal and the carrier by phosphorus pentoxide glasses or condensed higher phosphoric acids and another, irreversible part which is due to chemical reaction of the carrier substance (Al2O3, SiO2) with the poison to phosphates. The deposits from the reversible part of the process can be removed by washing with water or heating and sublimation in a poison-free gas stream.1.(1) Covering of the surfaces of the noble metal and carriers by P4O10or polyphosphoric acid coatings. As these coatings can be removed by simple means, this is described as the “reversible” part of the phosphoric poisoning process.2.(2) At the high temperatures prevailing in the systems considered here, phosphorus can undergo an irreversible reaction with the conventional carrier materials forming phosphates and mixed oxides. Considerable quantities of phosphorus can be deposited in the catalyst in this way, this leading to clogging of the pores and inclusion of noble metal crystallites. This aspect of the behaviour of phosphorus is typical of non-selective catalyst poisons, which include such substances as Si, As, Pb, Zn and other heavy metals.The course of catalyst poisoning, the kinetics of poisoning and the distribution of the phosphorus throughout the catalyst are described in a following paper[4].