Ru-Zn催化剂在苯选择加氢制环己烯反应中的粒径效应

doi:10.7503/cjcu20150288

摘要/Abstract

摘要：

采用共沉淀法制备了水溶性聚合物修饰的苯选择加氢制环己烯Ru-Zn催化剂, 并用X射线衍射、透射电镜、 X射线能量色散谱、 X射线光电子能谱和氮气物理吸附等对加氢后催化剂进行了表征. 结果表明, 水溶性聚合物的种类和聚乙二醇-20000(PEG-20000)的用量对Ru-Zn催化剂微晶尺寸有显著影响. 在ZnSO₄存在下, 随着Ru-Zn催化剂Ru微晶尺寸增加, 苯转化率降低, 环己烯最高收率则呈火山型变化趋势. 用0.4 g PEG-20000修饰的Ru-Zn催化剂[m(PEG-20000)∶m(Ru)=0.2]Ru的微晶尺寸为4.8 nm, 环己烯最高收率为62.2%. Ru微晶尺寸影响催化剂表面的Zn/Ru原子比, 进而影响Ru-Zn催化剂性能.

关键词: 苯, 选择加氢, 环己烯, 水溶性聚合物, 粒径效应

Abstract:

Ru-Zn catalysts modified by water soluble polymers were prepared by a precipitation method. The catalysts after hydrogenation were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy and N₂physisorption. It was found that the type of water-soluble polymers and the dosage of PEG-20000 imposed a remarkable effect on the particle size of Ru. With the Ru particle size in Ru-Zn catalysts increasing, benzene conversion decreased, and the maximum cyclohexene yield showed a volcanic-type variation tendency. When the Ru particle size of the Ru-Zn catalyst modified by 0.4 g PEG[m(PEG-20000)∶m(Ru)=0.2] was 4.8 nm, a maximum cyclohexene yield of 62.2% was obtained on this catalyst. The Ru particle size could produce an effect on the Zn/Ru atomic ratio on the catalyst surface, which was the primary reason why the Ru particle size could affect the performance of Ru-Zn catalysts.

Key words: Benzene, Selective hydrogenation, Cyclohexene, Water-soluble polymer, Particle size effect

中图分类号:

O643

TrendMD:

孙海杰, 陈凌霞, 黄振旭, 刘寿长, 刘仲毅. Ru-Zn催化剂在苯选择加氢制环己烯反应中的粒径效应. 高等学校化学学报, 2015, 36(10): 1969.

SUN Haijie, CHEN Lingxia, HUANG Zhenxu, LIU Shouchang, LIU Zhongyi. Particle Size Effect of Ru-Zn Catalysts on Selective Hydrogenation of Benzene to Cyclohexene^†. Chem. J. Chinese Universities, 2015, 36(10): 1969.

图/表 10

Fig.1 XRD patterns of Ru-Zn catalysts modified by different water-soluble polymers before(A) and

Fig.2 FTIR spectra of Ru-Zn catalysts modified by different water-soluble polymers after hydrogenation(A) and the mechanism of the water-soluble polymers in preparing Ru-Zn catalysts with different particle sizes(B)a. Blank; b. 0.4 g PVA-1750; c. 0.4 g PEG-20000; d. 0.4 g PEG-10000; e. 0.8 g PEG-20000; f. 1.2 g PEG-20000.

Fig.3 TEM images of the Ru-Zn catalysts modified by different dosages of PEG-20000(A) 1.2 g PEG-20000; (B) 0.4 g PEG-10000; (C) 0.4 g PEG-20000; (D) 0.4 g PVA-1750; (E) blank.

Fig.4 Particle size distribution of the Ru-Zn catalysts modified by different dosages of PEG-20000 (A) 1.2 g PEG-20000; (B) 0.4 g PEG-10000; (C) 0.4 g PEG-20000; (D) 0.4 g PVA-1750; (E) blank.

Table 1 Particle size, compositions and texture properties of Ru-Zn catalysts modified by different water-soluble polymers after hydrogenation

Modifier	Particle size/nm	Zn/Ru(atomic ratio)		S_BET/(m²·g^-1)	d_pore/nm	V_pore/(cm³·g^-1)
Modifier	Particle size/nm	Bulk^a		S_BET/(m²·g^-1)	d_pore/nm	Surface^b
Blank	5.9	0.31	0.29	65	0.12	7.54
0.4 g PVA-1750	5.6	0.31	0.27	66	0.11	7.69
0.4 g PEG-20000	4.8	0.31	0.25	67	0.12	7.87
0.4 g PEG-10000	4.2	0.30	0.22	68	0.11	7.89
0.8 g PEG-20000	3.7	0.31	0.20	70	0.09	7.99
1.2 g PEG-20000	3.0	0.31	0.17	72	0.10	7.95

Fig.5 XPS spectra of the Ru-Zn catalyst modified by 0.4 g of PEG-20000(A) Ru3p32; (B) Zn2p32; (C) Zn LMM; (D) S2p32.

Fig.6 Performance of Ru-Zn catalysts modified by different water-soluble polymers for selective hydrogenation of benzene to cyclohexenea. Blank; b. 0.4 g PVA-1750; c. 0.4 g PEG-20000; d. 0.4 g PEG-10000; e. 0.8 g PEG-20000; f. 1.2 g PEG-20000.

Fig.7 Correlation of surface molar ratio of Zn/Ru and particle size with the maximum cyclohexene yield

Fig.8 Hückel molecular orbitals of benzene(A), the interaction between the d orbital of Ru and Hückel antibonding orbital(Ψ4 and Ψ5) of benzene(B) and the selective hydrogenation of benzene to cyclohexene over Ru-Zn catalyst surface(C)

Fig.9 Reusability of the Ru-Zn catalyst modified by 0.4 g of PEG-20000

参考文献 26

[1]	Wang Z. B., Zhang Q., Lu X. F., Chen S. J., Liu C. J., Chin. J. Catal., 2015, 36(3), 400—407
	(王正宝, 张琪, 路晓飞, 陈双佳, 刘春杰. 催化学报,2015, 36(3), 400—407)
[2]	Sun H. J., Li Y. Y., Li S. H., Zhang Y. X., Liu S. C., Liu Z. Y., Ren B. Z., Acta Phys. Chim. Sin., 2014, 30(7), 1332—1340
	(孙海杰, 李永宇, 李帅辉, 张元馨, 刘寿长, 刘仲毅, 任保增. 物理化学学报,2014, 30(7), 1332—1340)
[3]	Zhang Y., Fu H. Y., Li R. X., Chen H., Li X. J., Chin. J. Inorg. Chem., 2013, 29(3), 577—582
	(张晔, 付海燕, 李瑞祥, 陈华, 李贤均. 无机化学学报,2013, 29(3), 577—582)
[4]	Sun H. J., Jiang H. B., Li S. H., Wang H. X., Pan Y. J., Dong Y. Y., Liu S. C., Liu Z. Y., Chin. J. Catal., 2013, 34(4), 684—694
	(孙海杰, 江厚兵, 李帅辉, 王红霞, 潘雅洁, 董莹莹, 刘寿长, 刘仲毅. 催化学报,2013, 34(4), 684—694)
[5]	Bu J., Liu J. L., Chen X. Y., Zhuang J. H., Yan S. R., Qiao M. H., He H. Y., Fan K. N., Catal. Commun., 2008, 9, 2612—2615
[6]	Zhou G. B., Tan X. H., Dou R. M., Pei Y., Fan K. N., Qiao M. H., Sun B., Zong B. N., Sci. Sin. Chim., 2014, 44(1), 121—130
	(周功兵, 谭晓荷, 窦镕飞, 裴燕, 范康年, 乔明华, 孙斌, 宗保守. 中国科学: 化学,2014, 44(1), 121—130)
[7]	Milone C., Neri G., Donato A., Musolino M. G., Mercadante L., J. Catal., 1996, 159, 253—258
[8]	Singh U. K., Vannice M. A., Appl. Catal. A, 2001, 213, 1—24
[9]	Sun H. J., Jiang H. B., Li S. H., Dong Y. Y., Wang H. X., Pan Y. J., Liu S. C., Tang M. S., Liu Z. Y., Chem. Eng. J., 2013, 218, 415—424
[10]	Wu J. M., Yang Y. F., Chen J. L., Chem. Ind. Eng. Prog., 2003, 22(3), 295—297
	(吴济民, 杨炎锋, 陈聚良. 化工进展,2003, 22(3), 295—297)
[11]	Hu S. C., Chen Y. W., Ind. Eng. Chem. Res., 2001, 40(26), 6099—6104
[12]	Wang J. Q., Wang Y. Z., Xie S. H., Qiao M. H., Li H. X., Fan K. N., Appl. Catal. A, 2004, 272, 29—36
[13]	Zhang P., Wu T. B., Jiang T., Wang W. T., Liu H. Z., Fan H. L., Zhang Z. F., Han B. X., Green Chem., 2013, 15, 152—159
[14]	Sun H. J., Wang H. X., Jiang H. B., Li S. H., Liu S. C., Liu Z. Y., Yuan X. M., Yang K. J., Appl. Catal. A, 2013, 450, 160—168
[15]	Huang X., Zhang H., Liang L. Y., Tan B. E., Preg. Chem., 2010, 22(5), 953—961
[16]	Kötz R., Lewerenz H. J., Stucki S., J. Electrochem. Soc., 1983, 130(4), 825—829
[17]	Peplinski B., Unger W. E. S., Grohmann I., Appl. Surf. Sci., 1992, 62(3), 115—129
[18]	Ramos-Fernándze E. V., Ferreira A. E. P., Sepúlveda-Escribano A., Kapteijn F., Rodríguez-Reinoso F., J. Catal., 2008, 258, 52—60
[19]	Nefedov V. I., J. Electron Spectrosc. Relat. Phenom., 1982, 25(1), 29—47
[20]	Sun H. J., Zhang X. D., Chen Z. H., Zhou X. L., Guo W., Liu Z. Y., Liu S. C., Chin. J. Catal., 2011, 32(2), 224—230
	(孙海杰, 张旭东, 陈志浩, 周小莉, 郭伟, 刘仲毅, 刘寿长. 催化学报,2011, 32(2), 224—230)
[21]	Zhao S. L., Chen J. R., Zhou Y. F., Xie Y. M., Li X. J., Chem. J. Chinese Universities, 2004, 25(8), 1552—1554
	(赵松林, 陈俊如, 周娅芬, 谢永美, 李贤均. 高等学校化学学报,2004, 25(8), 1552—1554)
[22]	Fan G. Y., Jiang W. D., Wang J. B., Li R. X., Chen H., Li X. J., Catal. Commun., 2008, 10, 98—102
[23]	Mazzieri V. A., L’Argentière P. C., Ind. Eng. Chem. Res., 2003, 42, 2269—2272
[24]	Struijk J., d’Angremond M., Lucas-De Regt W. J. M., Scholten J. J. F., Appl. Catal. A, 1992, 83, 263—295
[25]	Liu J. L., Zhu Y., Liu J., Pei Y., Li Z. H., Li H., Li H. X., Qiao M. H., Fan K. N., Appl. Catal. A, 2009, 268, 100—105
[26]	Sun H. J., Chen L. X., Li S. H., Jiang H. B., Zhang Y. X., Ren B. Z., Liu Z. Y., Liu S. C., J. Rare Earths, 2013, 31(10), 1023—1028