化工学报 ›› 2019, Vol. 70 ›› Issue (12): 4625-4634.DOI: 10.11949/0438-1157.20190395

• 催化、动力学与反应器 • 上一篇    下一篇

Ce在负载Pd催化苯酚氧化羰基化合成碳酸二苯酯反应中的作用

王志苗1,2(),张洪起1,周立超1,李芳1,2,薛伟1,2(),王延吉1,2()   

  1. 1. 河北工业大学化工学院,河北省绿色化工与高效节能重点实验室,天津 300130
    2. 天津市本质安全化工技术重点实验室,天津 300130
  • 收稿日期:2019-04-16 修回日期:2019-08-23 出版日期:2019-12-05 发布日期:2019-12-05
  • 通讯作者: 薛伟,王延吉
  • 作者简介:王志苗(1985—),女,硕士,实验师,wangzhimiao@hebut.edu.cn
  • 基金资助:
    国家自然科学基金项目(21776057);天津市自然科学基金项目(17JCYBJC20100);河北省留学人员科技活动择优资助项目(CL201605)

Role of Ce in supported Pd catalyst for oxidative carbonylation of phenol to diphenyl carbonate

Zhimiao WANG1,2(),Hongqi ZHANG1,Lichao ZHOU1,Fang LI1,2,Wei XUE1,2(),Yanji WANG1,2()   

  1. 1. Hebei Provincial Key Laboratory of Green Chemical Technology and High Efficient Energy Saving, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China
    2. Tianjin Key Laboratory of Chemical Process Safety, Tianjin 300130, China
  • Received:2019-04-16 Revised:2019-08-23 Online:2019-12-05 Published:2019-12-05
  • Contact: Wei XUE,Yanji WANG

摘要:

采用微乳液法制备了Ce为助剂的Pd-Ce-O/SiO2催化剂,用于苯酚氧化羰基化合成碳酸二苯酯(DPC)反应。活性评价结果显示,催化剂性能随着Ce用量的增加而提高,当Ce/Pd摩尔比为10/1时,苯酚转化率为64.4%,碳酸二苯酯选择性为83.4%。利用XRD表征发现,部分Ce4+进入到PdO晶格中,使得失活Pd原子中的电子更容易向Ce转移,从而易于再生,表现出更好的催化性能。根据上述结果,设计制备了Pd-O/CeO2催化剂用于本反应,苯酚转化率和碳酸二苯酯选择性分别仅为24.0%和23.3%。表征发现,在Pd-Ce-O/SiO2催化剂表面,Pd物种主要是PdO,而Pd-O/CeO2表面的Pd物种则以PdO2为主。由于苯酚氧化羰基化反应的活性中心为Pd(Ⅱ),所以Pd-O/CeO2催化性能较差。并且,由于Pd与CeO2之间存在强相互作用,催化剂表面Pd含量较低,这也是Pd-O/CeO2催化活性较差的原因之一。

关键词: 碳酸二苯酯, 氧化羰基化, 多相反应, 催化剂, 载体, 二氧化铈

Abstract:

A Pd-Ce-O/SiO2 catalyst with Ce as auxiliary was prepared by microemulsion method for oxidative carbonylation of phenol to synthesize diphenyl carbonate (DPC). The activity evaluation results showed that the catalyst performance increased with the increase of the amount of Ce. When the Ce/Pd molar ratio was 10/1, the phenol conversion rate was 64.4%, and the diphenyl carbonate selectivity was 83.4%. The XRD results showed that part of Ce4+ entered into PdO crystal lattice, therefore the electrons of deactivated Pd could easily be transferred to Ce. So the Pd-Ce-O/SiO2 catalyst could be easily regenerated and showed better performance. According to the above mentioned results, Pd-O/CeO2 was designed and prepared for oxidative carbonylation of phenol. However, unlike Pd-Ce-O/SiO2, Pd-O/CeO2 showed poor catalytic performance. The phenol conversion and DPC selectivity was only 24.0% and 23.3% respectively. The characterization results showed that PdO was the main species of Pd on the surface of Pd-Ce-O/SiO2, but there was more PdO2 on Pd-O/CeO2. Because Pd(Ⅱ) is the active site for oxidative carbonyation, Pd-O/CeO2 exhibited inferior activity to Pd-Ce-O/SiO2. In addition, in Pd-O/CeO2 catalyst, the surface Pd content was lower than that of other catalyst because of the strong interaction between Pd species and CeO2. That s one of the reasons for the poor activity of Pd-O/CeO2.

Key words: diphenyl carbonate, oxidative carbonlyation, heterogeneous reaction, catalyst, support, ceria

中图分类号: