Mechanistic insights into catalytic isomerization of propylene oxide over TS-1

doi:10.11949/0438-1157.20210519

Abstract

Abstract:

One-step catalytic epoxidation of propylene with H₂ and O₂ to produce propylene oxide (PO) has incomparable advantages over traditional industrial processes for PO production because of economic and environmental considerations. The formation of byproducts from PO isomerization catalyzed by TS-1 was studied considering that the bifunctional Au/TS-1 catalysts have exhibited superior PO performance in this reaction. By combining with the catalytic performance of PO isomerization and FT-IR results over the uncalcined TS-1 (TS-1-B) and Au/TS-1-B catalyst with blocked micropores, the formation pathways and corresponding energy changes of propanal and acetone over Ti-Defect site were explored with theoretical calculations. The results show that the isomerization of PO on TS-1 mainly undergoes two transition states of carbon-oxygen bond cleavage and hydrogen atom rearrangement, and the bidentatepropoxy species intermediate with a five-member ring. Compared to propanal, acetone has a lower selectivity from PO isomerization because of the higher transition state energy barrier of hydrogen atom rearrangement during its formation process. The PO adsorption and isomerization mechanism on TS-1 disclosed here will provide a theoretical basis for the structural modification of the titanium-based propylene epoxidation catalyst to enhance PO desorption, thereby improving PO selectivity.

Key words: propylene oxide isomerization, reaction mechanism, titanium silicate zeolite, theoretical calculation, propylene epoxidation

摘要：

丙烯氢氧环氧化一步法制备环氧丙烷（PO）相比于传统的PO工业生产方法在经济和环保方面具有不可比拟的优势。Au/TS-1双功能催化剂在该反应中展现出较优的PO性能，针对其中TS-1催化PO开环异构生成副产物进行了研究，结合PO在堵孔TS-1分子筛（TS-1-B）和Au/TS-1-B催化剂上的反应性能和红外表征结果，采用理论计算探究了Ti-Defect位点上丙醛和丙酮的生成路径以及涉及的能量变化。结果显示PO在TS-1上的异构化主要经历碳氧键断裂和氢原子转移重排两个过渡态，以及具有五元环结构的双配位丙氧基物种中间体。相比于丙醛，丙酮由于生成过程中氢原子重排的过渡态能垒较高而具有更低的异构化选择性。所揭示的TS-1上PO吸附及异构化反应机制将为钛基丙烯环氧化催化剂的结构改性以增强PO脱附从而提高PO选择性提供理论依据。

关键词: 环氧丙烷异构化, 反应机理, 钛硅分子筛, 理论计算, 丙烯环氧化

CLC Number:

TQ 426.1

Gang WANG,Xuezhi DUAN,Weikang YUAN,Xinggui ZHOU. Mechanistic insights into catalytic isomerization of propylene oxide over TS-1[J]. CIESC Journal, 2021, 72(10): 5150-5158.

王刚,段学志,袁渭康,周兴贵. 钛硅分子筛TS-1催化环氧丙烷异构反应的机理探究[J]. 化工学报, 2021, 72(10): 5150-5158.

Figures/Tables 11

Fig.1 Schematic diagram of propylene epoxidation with H2 and O2 to PO and its isomerization over Au/TS-1 catalyst

Fig.2 The optimized 9T clusters model of TS-1 employed for the calculation

Table 1 Comparison of Ti—O bond lengths between calculated and experimental values

键类型	Ti—O键键长 /nm
键类型	计算值	实验值
Ti—O(1)	0.181
Ti—O(2)	0.176
Ti—O(3)	0.182
Ti—O(4)	0.175
平均值	0.179	0.1793±0.0007^[27]

Fig.3 Structural characterization of synthesized titanosilicate

Table 2 BET surface area and pore parameters of TS-1-B and TS-1-O

样品

处理温度/℃

S_BET/

(m²?g^-1)

V_micro/

(cm³?g^-1)

V_total/

(cm³?g^-1)

Fig.4 Typical HAADF-STEM image and corresponding particle size distribution of Au/TS-1-B catalyst

Fig. 5 Catalytic performance of PO isomerization and over-oxidation over TS-1-B and Au/TS-1-B

Fig.6 The key structures and bond lengths during PO isomerization to produce propanal over TS-1 (Unit: nm)

Fig.7 Energy profile for PO isomerization to produce propanal over TS-1

Fig.8 The key structures and bond lengths during PO isomerization to produce acetone over TS-1 (Unit: nm)

Fig.9 Energy profile for PO isomerization to produce acetone over TS-1

References 41

1	Nijhuis T A, Makkee M, Moulijn J A, et al. The production of propene oxide: catalytic processes and recent developments[J]. Industrial & Engineering Chemistry Research, 2006, 45(10): 3447-3459.
2	Teržan J, Huš M, Likozar B, et al. Propylene epoxidation using molecular oxygen over copper- and silver-based catalysts: a review[J]. ACS Catalysis, 2020, 10(22): 13415-13436.
3	Hayashi T, Tanaka K, Haruta M. Selective vapor-phase epoxidation of propylene over Au/TiO₂ catalysts in the presence of oxygen and hydrogen[J]. Journal of Catalysis, 1998, 178(2): 566-575.
4	宋钊宁, 冯翔, 刘熠斌, 等. 丙烯直接气相临氢环氧化催化剂结构调控和催化剂构-效关系研究进展[J]. 化学进展, 2016, 28(12): 1762-1773.
	Song Z N, Feng X, Liu Y B, et al. Advances in manipulation of catalyst structure and relationship of Structure-Performance for Direct Propene Epoxidation with H₂ and O₂[J]. Progress in Chemistry, 2016, 28(12): 1762-1773.
5	Sinha A K, Seelan S, Tsubota S, et al. A three-dimensional mesoporous titanosilicate support for gold nanoparticles: vapor-phase epoxidation of propene with high conversion[J]. Angewandte Chemie International Edition, 2004, 43(12): 1546-1548.
6	Chowdhury B, Bravo-Suárez J J, Daté M, et al. Trimethylamine as a gas-phase promoter: highly efficient epoxidation of propylene over supported gold catalysts[J]. Angewandte Chemie International Edition, 2006, 45(3): 412-415.
7	杜威, 张志华, 段学志, 等. 丙烯氢氧环氧化动力学与反应器概念设计研究进展[J]. 化工学报, 2021, 72(1): 116-131.
	Du W, Zhang Z H, Duan X Zet al. A review on kinetics and reactor concept design of propylene epoxidation using H₂ and O₂[J]. 2021, 72(1): 116-131.
8	Zhan G W, Du M M, Sun D H, et al. Vapor-phase propylene epoxidation with H₂/O₂ over bioreduction Au/TS-1 catalysts: synthesis, characterization, and optimization[J]. Industrial & Engineering Chemistry Research, 2011, 50(15): 9019-9026.
9	Lee W S, Cem Akatay M, Stach E A, et al. Reproducible preparation of Au/TS-1 with high reaction rate for gas phase epoxidation of propylene[J]. Journal of Catalysis, 2012, 287: 178-189.
10	Lu J Q, Li N, Pan X R, et al. Direct propylene epoxidation with H₂ and O₂ over In modified Au/TS-1 catalysts[J]. Catalysis Communications, 2012, 28: 179-182.
11	Lee W S, Cem Akatay M, Stach E A, et al. Enhanced reaction rate for gas-phase epoxidation of propylene using H₂ and O₂ by Cs promotion of Au/TS-1[J]. Journal of Catalysis, 2013, 308: 98-113.
12	Lu J Q, Zhang X M, Bravo-Suárez J J, et al. Effect of composition and promoters in Au/TS-1 catalysts for direct propylene epoxidation using H₂ and O₂[J]. Catalysis Today, 2009, 147(3/4): 186-195.
13	Feng X, Duan X Z, Qian G, et al. Au nanoparticles deposited on the external surfaces of TS-1: enhanced stability and activity for direct propylene epoxidation with H₂ and O₂[J]. Applied Catalysis B: Environmental, 2014, 150/151: 396-401.
14	Feng X, Duan X Z, Yang J, et al. Au/uncalcined TS-1 catalysts for direct propene epoxidation with H₂ and O₂: effects of Si/Ti molar ratio and Au loading[J]. Chemical Engineering Journal, 2015, 278: 234-239.
15	Wang G, Cao Y Q, Zhang Z H, et al. Surface engineering and kinetics behaviors of Au/uncalcined TS-1 catalysts for propylene epoxidation with H₂ and O₂[J]. Industrial & Engineering Chemistry Research, 2019, 58:17300-17307.
16	Lee W S, Cem Akatay M, Stach E A, et al. Gas-phase epoxidation of propylene in the presence of H₂ and O₂ over small gold ensembles in uncalcined TS-1[J]. Journal of Catalysis, 2014, 313: 104-112.
17	Stangland E E, Stavens K B, Andres R P, et al. Characterization of gold-titania catalysts via oxidation of propylene to propylene oxide[J]. Journal of Catalysis, 2000, 191(2): 332-347.
18	Sinha A K, Seelan S, Akita T, et al. Vapor phase propylene epoxidation over Au/Ti-MCM-41 catalysts prepared by different Ti incorporation modes[J]. Applied Catalysis A: General, 2003, 240(1/2): 243-252.
19	Mul G, Zwijnenburg A, van der Linden B, et al. Stability and selectivity of Au/TiO₂ and Au/TiO₂/SiO₂ catalysts in propene epoxidation: an in situ FT-IR study[J]. Journal of Catalysis, 2001, 201(1): 128-137.
20	Namuangruk S, Khongpracha P, Pantu P, et al. Structures and reaction mechanisms of propene oxide isomerization on H-ZSM-5: an ONIOM study[J]. The Journal of Physical Chemistry B, 2006, 110(51): 25950-25957.
21	Wells D H, Delgass W N, Thomson K T. Evidence of defect-promoted reactivity for epoxidation of propylene in titanosilicate (TS-1) catalysts: a DFT study[J]. Journal of the American Chemical Society, 2004, 126(9): 2956-2962.
22	Li M Z, Yan X Y, Zhu M Y, et al. Insight into the stereoselectivity of TS-1 in epoxidation of cis/trans-2-hexene: a computational study[J]. Catalysis Science & Technology, 2018, 8(19): 4975-4984.
23	Wells D H, Joshi A M, Delgass W N, et al. A quantum chemical study of comparison of various propylene epoxidation mechanisms using H₂O₂ and TS-1 catalyst[J]. The Journal of Physical Chemistry. B, 2006, 110(30): 14627-14639.
24	Grimme S, Ehrlich S, Goerigk L. Effect of the damping function in dispersion corrected density functional theory[J]. Journal of Computational Chemistry, 2011, 32(7): 1456-1465.
25	Li M Z, Wang Y C, Wu Y, et al. Structure and catalytic activity of a newly proposed titanium species in a Ti-YNU-1 zeolite: a density functional theory study[J]. Catalysis Science & Technology, 2017, 7(18): 4105-4114.
26	Panyaburapa W, Nanok T, Limtrakul J. Epoxidation reaction of unsaturated hydrocarbons with H₂O₂ over defect TS-1 investigated by ONIOM method: formation of active sites and reaction mechanisms[J]. The Journal of Physical Chemistry C, 2007, 111(8): 3433-3441.
27	Lamberti C, Bordiga S, Arduino D, et al. Evidence of the presence of two different framework Ti(Ⅳ) species in Ti-Silicalite-1 in vacuo conditions: an EXAFS and a photoluminescence study[J]. The Journal of Physical Chemistry B, 1998, 102(33): 6382-6390.
28	Deng X J, Wang Y N, Shen L, et al. Low-cost synthesis of titanium silicalite-1 (TS-1) with highly catalytic oxidation performance through a controlled hydrolysis process[J]. Industrial & Engineering Chemistry Research, 2013, 52(3): 1190-1196.
29	Zuo Y, Wang X S, Guo X W. Synthesis of titanium silicalite-1 with small crystal size by using mother liquor of titanium silicalite-1 as seeds (Ⅱ): Influence of synthesis conditions on properties of titanium silicalite-1[J]. Microporous and Mesoporous Materials, 2012, 162: 105-114.
30	Elango M, Maciel G S, Palazzetti F, et al. Quantum chemistry of C₃H₆O molecules: structure and stability, isomerization pathways, and chirality changing mechanisms[J]. The Journal of Physical Chemistry. A, 2010, 114(36): 9864-9874.
31	Zwijnenburg A, Makkee M, Moulijn J A. Increasing the low propene epoxidation product yield of gold/titania-based catalysts[J]. Applied Catalysis A: General, 2004, 270(1/2): 49-56.
32	Panayotov D, McEntee M, Burrows S, et al. Infrared studies of propene and propene oxide adsorption on nanoparticulate Au/TiO₂[J]. Surface Science, 2016, 652: 172-182.
33	Harris J W, Arvay J, Mitchell G, et al. Propylene oxide inhibits propylene epoxidation over Au/TS-1[J]. Journal of Catalysis, 2018, 365: 105-114.
34	Imanaka T, Okamoto Y, Teranishi S. The isomerization of propylene oxide on zeolite catalysts[J]. Bulletin of the Chemical Society of Japan, 1972, 45(11): 3251-3254.
35	Nijhuis T A, Visser T, Weckhuysen B M. Mechanistic study into the direct epoxidation of propene over gold/titania catalysts[J]. The Journal of Physical Chemistry B, 2005, 109(41): 19309-19319.
36	Nijhuis T A, Visser T, Weckhuysen B M. The role of gold in gold-titania epoxidation catalysts[J]. Angewandte Chemie International Edition, 2005, 44(7): 1115-1118.
37	Ruiz A, van der Linden B, Makkee M, et al. Acrylate and propoxy-groups: contributors to deactivation of Au/TiO₂ in the epoxidation of propene[J]. Journal of Catalysis, 2009, 266(2): 286-290.
38	Yao S N, Xu L H, Wang J, et al. Activity and stability of titanosilicate supported Au catalyst for propylene epoxidation with H₂ and O₂[J]. Molecular Catalysis, 2018, 448: 144-152.
39	Chowdhury B, Bando K K, Bravo-Suárez J J, et al. Activity of silylated titanosilicate supported gold nanoparticles towards direct propylene epoxidation reaction in the presence of trimethylamine[J]. Journal of Molecular Catalysis A: Chemical, 2012, 359: 21-27.
40	Kanungo S, Keshri K S, van Hoof A J F, et al. Silylation enhances the performance of Au/Ti-SiO₂ catalysts in direct epoxidation of propene using H₂ and O₂[J]. Journal of Catalysis, 2016, 344: 434-444.
41	Kanungo S, Keshri K S, Hensen E J M, et al. Direct epoxidation of propene on silylated Au-Ti catalysts: a study on silylation procedures and the effect on propane formation[J]. Catalysis Science & Technology, 2018, 8(12): 3052-3059.

[1]	ZHANG Zhihua, DU Wei, DUAN Xuezhi, ZHOU Xinggui. Au nanoparticles immobilized on surface modified TS-1-B as high-efficiency bifunctional catalyst for propylene epoxidation with H₂and O₂ [J]. CIESC Journal, 2021, 72(7): 3613-3625.
[2]	YE Kai, LIU Xianghua, JIANG Yue, YU Ying, ZHAO Yafei, ZHUANG Ye, ZHENG Jinbao, CHEN Binghui. Combing low-temperature plasma with CeO₂/13X for toluene degradation [J]. CIESC Journal, 2021, 72(7): 3706-3715.
[3]	ZHU Qianqian, JIN Haibo, GUO Xiaoyan, HE Guangxiang, MA Lei, ZHANG Rongyue, GU Qingyang, YANG Suohe. Study on synthesis of ε-caprolactone with MgO catalysis by Baeyer-Villiger green oxidation of cyclohexanone in H₂O₂/acetonitrile system [J]. CIESC Journal, 2021, 72(5): 2638-2646.
[4]	DU Wei, ZHANG Zhihua, DUAN Xuezhi, ZHOU Xinggui. A review on kinetics and reactor concept design of propylene epoxidation using H₂ and O₂ [J]. CIESC Journal, 2021, 72(1): 116-131.
[5]	Dong WANG, Yaru LIU, Zhuo CHEN, Zunli KOU, Yuehong LU. Effects on performance of small water-source heat pump water heater with CO₂ by refrigerant charge and determination of optimal value [J]. CIESC Journal, 2020, 71(S1): 397-403.
[6]	Hong ZHANG, Liu TANG. Study on reaction mechanism of p-type dopant Cp₂Mg in MOCVD gas phase [J]. CIESC Journal, 2020, 71(7): 3000-3008.
[7]	Yan JIN, Qian YANG, Wenbin ZHAO, Baoshan HU. Catalytic reaction system for controllable synthesis of graphene with chemical vapor deposition [J]. CIESC Journal, 2020, 71(6): 2564-2585.
[8]	Yonggang CHENG, Jiao LIU, Zhennan HAN, Lei SHI, Guangwen XU. Transfer dynamics and reaction control mechanism over methanation catalyst particles in transport bed [J]. CIESC Journal, 2019, 70(8): 2876-2887.
[9]	Lufeng WANG, Xin QIAN, Lifang DENG, Haoran YUAN. Recent progress on catalysts about electrochemical synthesis of ammonia from nitrogen [J]. CIESC Journal, 2019, 70(8): 2854-2863.
[10]	Wensheng LIANG, Jiangtao LIU, Yue ZHAO, Wei HUANG, Zhijun ZUO. Theoretical calculation of effect of NiO and Ni catalysts for benzoic acid pyrolysis [J]. CIESC Journal, 2019, 70(4): 1429-1435.
[11]	Tianshui LIANG, Zongying WANG, Kun GAO, Runwan LI, Zheng WANG, Wei ZHONG, Jun ZHAO. Analysis of fire suppression effectiveness of ultra-fine water mist containing iron compounds additives in cup burner [J]. CIESC Journal, 2019, 70(3): 1236-1242.
[12]	ZHANG Yi, LI Jianbo, WANG Quanhai, LU Xiaofeng. Simulation of NO_x formation in novel dual circulating fluidized-bed boiler [J]. CIESC Journal, 2018, 69(4): 1703-1713.
[13]	LI Shuyan, SUN Lina, SHEN Shujun, CHENG Tianxing, CHENG Shuanghua, CHEN Jiuxi. Reaction of diaryl disulfides with nitroarenes [J]. CIESC Journal, 2017, 68(6): 2394-2398.
[14]	ZHANG Hongmei, LIN Feng, REN Mingqi, LI Jinlian, HAO Yulan, WU Hongjun, ZHAO Jingying, ZHAO Liang, HE Yongdian. Free radical models of small molecular alkane pyrolysis [J]. CIESC Journal, 2017, 68(4): 1423-1433.
[15]	YANG Jia, ZHANG Zhihua, FENG Xiang, DUAN Xuezhi, ZHOU Jinghong, ZHOU Xinggui. Effect of Ag addition on performance of Au/TS-1-B catalyst in gas phase propylene epoxidation [J]. CIESC Journal, 2016, 67(9): 3684-3691.