The ligand coordination approach for improving the stability of low-mercury catalyst in the hydrochlorination of acetylene

doi:10.1016/j.cjche.2016.12.003

Abstract

Abstract: Mercuric chloride supported on activated carbon (HgCl₂/AC) is used as an industrial catalyst for the hydrochlorination of acetylene. Loss of HgCl₂ by sublimating from the surface of activated carbon causes the irreversible deactivation of mercury catalyst and environmental pollution. In this work, a ligand coordination approach based on the Principle of Hard and Soft Acids and Bases (HSAB) was employed to design more stable lowmercury catalyst. The low-mercury catalysts (4% HgCl₂ loading) were prepared by using HgCl₂ and potassium halides (KX, X=Cl, I) as precursors. The HgCl₂-4KI/AC catalyst showed best catalytic stability than HgCl₂/AC and HgCl₂-4KCl/AC in the hydrochloriantion of acetylene. HgCl₂ could form more stable complex with KI, K₂HgI₄ as the main active component of the HgCl₂-4KI/AC catalyst. The characterizations of XRD and EDX analysis illustrated that the active component of HgCl₂-4KI/AC was highly dispersed on the surface of activated carbon. The sublimation rates of HgCl₂ from the catalysts verified that the active component with larger stability constant had better thermal stability. Using Hg(Ⅱ) complexes with high stability constant as the active component may be the research direction of developing highly stable low-mercury catalyst for the hydrochlorination of acetylene.

Key words: Low-mercury catalyst, Sublimation, K₂HgI₄, Ligand coordination, Acetylene hydrochlorination

摘要： Mercuric chloride supported on activated carbon (HgCl₂/AC) is used as an industrial catalyst for the hydrochlorination of acetylene. Loss of HgCl₂ by sublimating from the surface of activated carbon causes the irreversible deactivation of mercury catalyst and environmental pollution. In this work, a ligand coordination approach based on the Principle of Hard and Soft Acids and Bases (HSAB) was employed to design more stable lowmercury catalyst. The low-mercury catalysts (4% HgCl₂ loading) were prepared by using HgCl₂ and potassium halides (KX, X=Cl, I) as precursors. The HgCl₂-4KI/AC catalyst showed best catalytic stability than HgCl₂/AC and HgCl₂-4KCl/AC in the hydrochloriantion of acetylene. HgCl₂ could form more stable complex with KI, K₂HgI₄ as the main active component of the HgCl₂-4KI/AC catalyst. The characterizations of XRD and EDX analysis illustrated that the active component of HgCl₂-4KI/AC was highly dispersed on the surface of activated carbon. The sublimation rates of HgCl₂ from the catalysts verified that the active component with larger stability constant had better thermal stability. Using Hg(Ⅱ) complexes with high stability constant as the active component may be the research direction of developing highly stable low-mercury catalyst for the hydrochlorination of acetylene.

关键词: Low-mercury catalyst, Sublimation, K₂HgI₄, Ligand coordination, Acetylene hydrochlorination

Xiaolong Xu, Haihua He, Jia Zhao, Bailin Wang, Shanchuan Gu, Xiaonian Li. The ligand coordination approach for improving the stability of low-mercury catalyst in the hydrochlorination of acetylene[J]. , 2017, 25(9): 1217-1221.

References

[1] T. Yang, Production, application and prospect of PVC resin in China, China Plast. 22(2) (2008) 1-8(in Chinese).
[2] Q.S. Han, F. Sun, Contrast analysis on PVC produced by ethylene method and acetylene method, Polyvinyl Chloride 37(9) (2009) 5-7(in Chinese).
[3] F.Z. Xin, Contrast of vinyl chloride production processes, Yunnan Chem. Technol. 37(1) (2010) 65-67(in Chinese).
[4] X.B. Wei, H.B. Shi, W.Z. Qian, G.H. Luo, Y. Jin, F. Wei, Gas-phase catalytic hydrochlorination of acetylene in a two-stage fluidized-bed reactor, Ind. Eng. Chem. Res. 48(1) (2009) 128-133.
[5] J.L. Bing, C.Z. Li, Review on development of China's PVC industry in the past 10 years and analysis on the trends in the year 2010, Polyvinyl Chloride 39(5) (2001) 1-8(in Chinese).
[6] J.L. Zhang, N. Liu, W. Li, B. Dai, Progress on cleaner production of vinyl chloride monomers over non-mercury catalysts, Front. Chem. Sci. Eng. 5(4) (2011) 514-520.
[7] G.J. Hutchings, D.T. Grady, Effect of drying conditions on carbon supported mercuric chloride catalysts, Appl. Catal. 16(1985) 411-415.
[8] G.J. Hutchings, Vapor phase hydrochlorination of acetylene:Correlation of catalytic activity of supported metal chloride catalysts, J. Catal. 96(1985) 292-295.
[9] K. Zhou, W. Wang, Z. Zhao, G.H. Luo, J.T. Miller, M.S. Wong, F. Wei, Synergistic GoldBismuth catalysis for non-mercury hydrochlorination of acetylene to vinyl chloride monomer, ACS Catal. 4(2014) 3112-3116.
[10] K. Zhou, J.C. Jia, C.H. Li, H. Xu, J. Zhou, G.H. Luo, F. Wei, A low content Au-based catalyst for hydrochlorination of C₂H₂ and its industrial scale-up for future PVC processes, Green Chem. 17(2015) 356-364.
[11] J. Zhao, J.T. Xu, J.H. Xu, J. Ni, T.T. Zhang, X.L. Xu, X.N. Li, Activated-carbon-supported gold-cesium(I) as highly effective catalysts for hydrochlorination of acetylene to vinyl chloride, ChemPlusChem 80(2015) 196-201.
[12] J. Zhao, J.T. Xu, J.H. Xu, T.T. Zhang, X.X. Di, J. Ni, X.N. Li, Enhancement of Au/AC acetylene hydrochlorination catalyst activity and stability via nitrogen-modified activated carbon support, Chem. Eng. J. 262(2015) 1152-1160.
[13] J. Zhao, S.C. Gu, X.L. Xu, T.T. Zhang, Y. Yu, X.X. Di, J. Ni, Z.Y. Pan, X.N. Li, Supported ionic-liquid-phase-stabilized Au(Ⅲ) catalyst for acetylene hydrochlorination, Catal. Sci. Technol. 6(2016) 3263-3270.
[14] S.A. Mitchenko, T.V. Krasnyakova, I.V. Zhikharev, Catalytic hydrochloriantion of acetylene on mechanochemically-activated K₂PdCl₄, Theor. Exp. Chem. 44(5) (2008) 316-319.
[15] L. Wang, F. Wang, J.D. Wang, X.L. Tang, Y.L. Zhao, D. Yang, F.M. Jia, T. Hao, Hydrochlorination of acetylene to vinyl chloride over Pd supported on zeolite Y, React. Kinet. Mech. Catal. 110(2013) 187-194.
[16] L. Wang, F. Wang, J.D. Wang, Non-mercury catalytic acetylene hydrochlorination over a NH₄F-urea-modified Pd/HY catalyst for vinyl chloride monomer production, New J. Chem. 40(2016) 3019-3023.
[17] Y.F. Pu, J.L. Zhang, L. Yu, Y.H. Jin, W. Li, Active ruthenium species in acetylene hydrochlorination, Appl. Catal. A Gen. 488(2014) 28-36.
[18] G.B. Li, W. Li, H.Y. Zhang, Y.F. Pu, M.X. Sun, J.L. Zhang, Non-mercury catalytic acetylene hydrochlorination over Ru catalysts enhanced by carbon nanotubes, RSC Adv. 5(2015) 9002-9008.
[19] S.A. Mitchenko, T.V. Krasnyakova, R.S. Mitchenko, A.N. Korduban, Acetylene catalytic hydrochlorination over powder catalyst prepared by pre-milling of K₂PtCl₄ salt, J. Mol. Catal. A Chem. 275(2007) 101-108.
[20] S.A.Mitchenko,E.V.Khomutov,A.A.Shubin, Y.M. Shul'ga,Catalytichydrochlorination of acetyleneby gaseous HCl on the surfaceof mechanically pre-activated K₂PtCl₆ salt, J. Mol. Catal. A Chem. 212(2004) 345-352.
[21] X. Huang, F. Yu, M.Y. Zhu, F.H. Ouyang, B. Dai, J.M. Dan, Hydrochlorination of acetylene using expanded multilayered vermiculite (EML-VMT)-supported catalysts, Chin. Chem. Lett. 26(2015) 1101-1104.
[22] J. Zhang, T.Y. Liu, R. Chen, X.H. Liu, Vermiculite as a natural silicate crystal for hydrogen generation from photocatalytic splitting of water under visible light, RSC Adv. 4(2014) 406-408.
[23] L.L. Xu, X.G. Wang, H.Y. Zhang, B. Dai, Z.Y. Liu, Q.F. Zhang, Application of a novel carbon carrier in acetylene hydrochlorination, Chem. Ind. Eng. Prog. 30(2011) 536-541(in Chinese).
[24] M.H. Chen, K. Xu, J.X. Liao, X.H. Chen, Effects of Cd cocatalytic mechanism in multielement catalytic system on performance of low-level mercury catalyst, Polyvinyl Chloride 42(5) (2014) 26-29(in Chinese).
[25] X.L. Xu, J. Zhao, C.S. Lu, T.T. Zhang, X.X. Di, S.C. Gu, X.N. Li, Improvement of the stability of Hg/AC catalysts by CsCl for the high-temperature hydrochlorination of acetylene, Chin. Chem. Lett. 27(2016) 822-826.
[26] Y. Zhou, Q. Yang, Q. Luo, W.W. Jiang, Preparation and optimization of a new-type low-mercury catalyst for hydrochlorination of acetylene, Appl. Chem. Ind. 40(12) (2011) 2147-2150(in Chinese).
[27] Z.Q. Chen, X.Y. Ma, Application of environmental low-mercury catalyst, China ChlorAlkali 6(2009) 9-11(in Chinese).
[28] P. Johnston, N. Carthey, G.J. Hutchings, Discovery, development, and commercialization of gold catalysts for acetylene hydrochlorination, J. Am. Chem. Soc. 137(2015) 14548-14557.
[29] X.J. Liu, Y.F. Zhu, F. Gao, Inorganic Element Chemistry, Science Press, Beijing, 2010(in Chinese).
[30] China Chlor-Alkali Industry Association, HG/T 4192-2011, Low-Level Mercury Catalyst for Chloroethylene Synthesis, Chemical Industry Press, Beijing, 2011(in Chinese).
[31] Y.C. Xie, N.F. Yang, Y.J. Liu, Y.Q. Tang, Spontaneous dispersion of some active components onto the surfaces of carriers, Sci. Sinica 26(1983) 337-350.
[32] R.G. Pearson, Hard and soft acids and bases, HSAB, part I fundamental principles, J. Chem. Educ. 45(9) (1965) 581-587.
[33] R.G. Pearson, Hard and soft acids and bases, HSAB, part Ⅱ underlying theories, J. Chem. Educ. 45(10) (1968) 643-648.