摘要
用MS GC对Pd Sn催化剂再生洗涤液进行了分析 ,用XPS和等离子光谱对催化剂活性组分Pd含量进行了检测 ,以了解催化剂在使用过程中表面的积碳、表面活性元素价态的变化及活性组分流失的情况 .结果表明 ,原料苯酚过多的吸附及Sn在催化剂表面上的富集而引起活性组分Pd浓度的相对下降 ,是造成催化剂失活的主要原因 .再生实验结果表明 ,用浓度为2 3%的丙酮洗涤液在 6 0℃下进行洗涤 ,在 30 0℃进行干燥 ,所得再生催化剂的活性较高 .此外 。
In order to investigate the deactivation of Pd-Sn catalyst for direct synthesis of diphenyl carbonate via heterogeneous catalysis, the components in the wa shing solution of the regeneration catalyst was measured by GC-MS, and there a ppeared only two peaks representing phenol and solvent respectively. The Pd cont ents in the fre sh and the used catalysts were analyzed by ICP, and the loss of active component Pd of the used catalyst was less than 10%. The deactivated and the fresh cataly st samples were characterized by XPS, revealing that the Sn element migrated to the catalyst surface after reaction, but the content of carbon on the catalyst surface did not increase, the valences of active component Pd and co-active co mponent Sn remained unchanged and exhibited as +2 and +4 respectively. Based on the above results, the main deactivation reason of the catalyst should be the se rious adsorption of phenol on the catalyst and the migration of Sn element to th e catalyst surface during the reaction. When acetone used as regeneration solven t (23 1%), solution temperature set to 60 ℃ and drying temperature set to 300 ℃, the activity of regenerated catalyst was higher. In addition, the addition o f promoter Ce could be helpful to the improvement of the catalyst life.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2003年第11期835-838,共4页
基金
国家自然科学基金资助项目 ( 2 0 0 760 3 6)
武汉市科委攻关项目(2 0 0 2 )
