Effect of ammonium salt on the distribution of titanium species in the synthesis of TS-1 zeolites
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摘要: 以(NH)4SO4作为晶化调节剂,通过调节铵盐添加量,合成出了不同钛物种分布的TS-1-X系列分子筛(X为铵盐与SiO2的物质的量比)。通过ICP-AES、FT-IR、UV-vis、UV-Raman等表征对TS-1-X系列分子筛中钛物种分布进行了系统的研究。以1-己烯环氧化为探针反应,考查了TS-1-X分子筛的催化性能。研究结果表明,适量铵盐不仅有利于钛从液相向固相富集,促进Ti元素进入MFI骨架结构,还有利于抑制晶粒过快生长,得到晶粒粒径小且分布均匀的TS-1分子筛;而过量的(NH)4SO4反而利于锐钛矿TiO2、无定型钛等非骨架钛物种的形成,同时促进晶粒过快生长得到大晶粒TS-1分子筛。最后,当n((NH4)2SO4)/n(SiO2) = 0.2时合成出反应性能最佳的骨架富钛TS-1,其对1-己烯转化率高达42%,同时H2O2的有效利用率为81.8%。此外,通过实验和表征考察了铵盐中各组分对TS-1性质的影响,发现铵盐通过自身的阴离子以及对pH值的改变,对TS-1晶化体系进行调节。Abstract: Titanium silicalite (TS-1) zeolites with different distribution of Ti species were synthesized through altering different amounts of (NH4)2SO4 as crystallization-mediating agent. The distribution of titanium species of TS-1-X samples (X represents the molar ratio of (NH4)2SO4 to SiO2) was systematically investigated via ICP-AES, FT-IR, UV-Vis, UV-Raman and other techniques. The TS-1-X zeolite samples were applied in the epoxidation of 1-hexene reaction. It was found that the appropriate amount of ammonium salt not only facilitated the enrichment of titanium species from liquid phase to solid phase and promoted the incorporation of Ti into the MFI skeleton, but also resulted in the formation of uniformly small TS-1 crystals due to the inhibition of rapid growth of crystals. However, much more amounts of (NH4)2SO4 led to the formation of extra-framework Ti, including anatase TiO2 and amorphous Ti species. Meanwhile it promoted the rapid growth of grain resulting in larger TS-1 crystals. Ti-rich TS-1 sample synthesized with molar ratio of (NH4)2SO4 to SiO2 of 0.2 exhibited higher conversion of 1-hexene (42 %) and effective utilization of H2O2 (81.8 %). In addition, the effect of ammonium salt’s composition on the properties of TS-1 was investigated by experiments and characterizations. It was found that ammonium salt could regulate the process of crystallization through its own anion and changing PH of the synthesis gel.
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Key words:
- α-olefin /
- titanosilicate zeolites /
- 1-hexene /
- epoxidation
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表 1 不同铵盐下TS-1合成体系pH值及钛分布
Table 1 Titanium distribution and pH value in different systems of TS-1
Catalyst pH value Ti/(Si+Ti) /%a in liquid in solid TS-1-0 11.9 6.2 1.6 TS-1-0.05 11.6 5.6 1.7 TS-1-0.1 11.4 5.4 1.8 TS-1-0.15 11.1 5.1 2.0 TS-1-0.2 10.7 4.7 2.3 TS-1-0.25 10.0 1.2 3.9 表 2 不同方法对钛物种的定量
Table 2 Quantitative results of Ti species from different methods
Sample ICP
Si/TiXPS
Si/TiTiframework/
Titotal
(XPS)I960/800 Unit-cell
volume (A3)TS-1-0 61.50 2.38 71.05 1.29 5330.54 TS-1-0.05 57.82 1.93 94.65 1.37 5334.26 TS-1-0.1 54.56 1.99 86.91 1.41 5338.02 TS-1-0.15 49.00 2.09 80.11 2.02 5349.23 TS-1-0.2 42.48 2.53 75.81 2.40 5352.86 TS-1-0.25 24.64 19.13 12.67 1.05 5321.20 表 3 不同TS-分子筛催化剂上1-己烯环氧化反应的评价
Table 3 Catalytic epoxidation of 1-hexene over different TS-1 catalysts
Catalyst 1-hexene conv. x/% Sel. s/% H2O2 conv. x/% H2O2 η/% TON epoxide others TS-1-0 31.1 86.8 13.2 42.8 72.6 235.1 TS-1-0.05 35.6 83.3 16.7 43.3 82.1 248.3 TS-1-0.1 37.9 81.3 18.7 45.9 82.5 255.1 TS-1-0.15 38.5 80.8 19.2 46.3 83.2 243.7 TS-1-0.2 42.8 80.1 19.9 48.8 87.7 231.3 TS-1-0.25 14.4 87.2 12.8 41.9 34.3 42.0 表 4 不同TS-1分子筛催化剂上1-己烯环氧化反应
Table 4 Catalytic epoxidation of 1-hexene over different TS-1 catalysts
Samples pH value Si/Ti I960/800 1-hexene
conv. x/%H2O2 η/% TON TS-1-A 11.14 51.4 1.93 38.5 83.2 243.6 TS-1-B 11.02 56.9 1.76 34.8 81.3 243.2 TS-1-C 10.79 61.9 1.49 32.6 82.5 247.4 表 5 不同TS-分子筛催化剂上1-己烯环氧化反应的评价
Table 5 The catalytic epoxidation of 1-hexene over different TS-1 catalysts
Catalyst Si/Ti 1-hexene
conv. x/%Sel. s /% H2O2
conv. x/%H2O2 η/% TON epoxide others TS-1-0 61.50 31.1 86.8 13.2 42.8 72.6 235.1 TS-1-N 61.31 31.0 86.3 13.7 42.5 72.9 233.0 -
[1] YAN W J, ZHANG G Y, YAN H, LIU Y B, CHEN X B, FENG X, JIN X, YANG C H. Liquid-phase epoxidation of light olefins over w and nb nanocatalysts[J]. ACS Sustainable Chem Eng,2018,6(4):4423−4452. doi: 10.1021/acssuschemeng.7b03101 [2] TARAMASSO M, PEREGO G, NOTARI B. Crystalline, porous material with silicalite structure-prepd. from silica and titanium oxide cpds. and used e. g. for alkylation, cracking etc. of organic cpds: US, 4410501[P]. 1983-10-18. [3] MANTEGAZZA M A, LEOFANTI G, PETRINI G, PADOVAN M, ZECCHINA A, BORDIGA S. Selective oxidation of ammonia to hydroxylamine with hydrogen peroxide on titanium based catalysts[J]. Stud Surf Sci Catal,1994,82:541−550. [4] XU L, PENG H G, ZHANG K, WU H H, CHEN L, LIU Y M, WU P. Core-shell-structured titanosilicate as a robust catalyst for cyclohexanone ammoximation[J]. ACS Catal,2013,3(1):103−110. doi: 10.1021/cs3006007 [5] YANG L B, XIN F, LIN J Z, ZHUANG Z, SUN R. Continuous heterogeneous cyclohexanone ammoximation reaction using a monolithic TS-1/cordierite catalyst[J]. RSC Adv,2014,4(52):27259−27266. doi: 10.1039/C4RA01789G [6] KONG L Y, LI G, WANG X S. Mild oxidation of thiophene over TS-1/H2O2[J]. Catal Today,2004,93−95:341−345. doi: 10.1016/j.cattod.2004.06.016 [7] GAO G H, CHENG S F, AN Y, SI X J, FU X L, LIU Y M, ZHANG H J, WU P, HE M Y. Oxidative desulfurization of aromatic sulfur compounds over titanosilicates[J]. ChemCatChem,2010,2(4):459−466. doi: 10.1002/cctc.200900073 [8] 刘斌, 李钢, 王祥生. TS-1/H2O2催化模拟汽油中噻吩的选择氧化研究[J]. 燃料化学学报,2006,34(5):629−632. doi: 10.3969/j.issn.0253-2409.2006.05.023LIU Bin, LI Gang, WANG Xiang-sheng. Selective oxidation of thiophene from model gasoline over TS-1/H2O2[J]. J Fuel Chem Technol,2006,34(5):629−632. doi: 10.3969/j.issn.0253-2409.2006.05.023 [9] SHEN C, WANG Y J, XU J H, LUO G S. Synthesis of TS-1 on porous glass beads for catalytic oxidative desulfurization[J]. Chem Eng J,2015,259:552−561. doi: 10.1016/j.cej.2014.08.027 [10] MILLINI R, MASSARA E P, PEREGO G, BELLUSS G. Framework composition of titanium silicalite-1[J]. J Catal,1992,137:497−503. doi: 10.1016/0021-9517(92)90176-I [11] NOTARI B. Titanium silicalites[J]. Catal Today,1993,18(2):163−172. doi: 10.1016/0920-5861(93)85029-Y [12] 陈晓晖, 林民, 陈宪, 米镇涛, 许锡恩. TS-1的丙烯环氧化性能研究[J]. 燃料化学学报,2001,21(5):426−429. doi: 10.3969/j.issn.0253-2409.2001.05.010CHEN Xiao-hui, LIN Min, CHEN Xian, MI Zhen-tao, XU Xi-en. Study on the epoxidation of propylene with catalyst TS-1[J]. J Fuel Chem Technol,2001,21(5):426−429. doi: 10.3969/j.issn.0253-2409.2001.05.010 [13] KUWAHARA Y, NISHIZAWA K, NAKAJIMA T, KAMEGAWA T, MORI K, YAMASHITA H. Enhanced catalytic activity on titanosilicate molecular sieves controlled by cation-pi interactions[J]. J Am Chem Soc,2011,133(32):12462−12465. doi: 10.1021/ja205699d [14] CORDEIRO P J, TILLEY T D. Enhancement of the catalytic activity of titanium-based terminal olefin epoxidation catalysts via surface modification with functionalized protic molecules[J]. ACS Catal,2011,1(5):455−467. doi: 10.1021/cs200017s [15] 马书启, 李钢, 王祥生, 金长子, 刘民, 郭新闻. 钛硅分子筛催化1-丁烯环氧化研究[J]. 燃料化学学报,2005,33(4):509−512. doi: 10.3969/j.issn.0253-2409.2005.04.027MA Shu-qi, LI Gang, WANG Xiang-sheng, JIN Chang-zi, LIU Min, GUO Xin-wen. 1-Butylene epoxidation over various titanosilicate molecular sieves[J]. J Fuel Chem Technol,2005,33(4):509−512. doi: 10.3969/j.issn.0253-2409.2005.04.027 [16] LIU Z F, DAVIS R J. Investigation of the structure of microporous Ti-Si mixed oxides by X-ray, UV reflectance, FT-Raman, and FT-IR Spectroscopies[J]. J Phys Chem,1994,98(4):1253−1261. doi: 10.1021/j100055a035 [17] WILDE N, PRECH J, PELZ M, KUBU M, CEJKA J, Glaser R. Accessibility enhancement of TS-1-based catalysts for improving the epoxidation of plant oil-derived substrates[J]. Catal Sci Technol,2016,6(19):7280−7288. doi: 10.1039/C6CY01232A [18] ZUO Y, LIU M, ZHANG T, MENG C G, GUO X W, SONG C S. Enhanced catalytic performance of titanium silicalite-1 in tuning the crystal size in the range 1200−200 nm in a tetrapropylammonium bromide system[J]. ChemCatChem,2015,7(17):2660−2668. doi: 10.1002/cctc.201500440 [19] LIN D, ZHANG Q D, QIN Z X, LI Q, FENG X, SONG Z N, CAI Z P, LIU Y B, CHEN X B, CHEN D, MINTOVA S, YANG C H. Reversing titanium oligomer formation towards high‐efficiency and green synthesis of titanium-containing molecular sieves[J]. Angew Chem Int Ed,2020,59:1−7. doi: 10.1002/anie.201914874 [20] 陈晓晖, 蔡丽蓉, 魏可镁. 表面活性剂Tween对TS-1合成及催化性能影响的研究[J]. 燃料化学学报,2005,33(1):112−116. doi: 10.3969/j.issn.0253-2409.2005.01.022CHEN Xiao-hui, CAI Li-rong, WEI Ke-mei. Effect of tween on synthesis and catalytic performance of TS-1[J]. J Fuel Chem Technol,2005,33(1):112−116. doi: 10.3969/j.issn.0253-2409.2005.01.022 [21] FAN W B, DUAN R G, YOKOI T, WU P, KUBOTA Y, TATSUMI T. Synthesis, crystallization mechanism, and catalytic properties of titanium-rich TS-1 free of extraframework titanium species[J]. J Am Chem Soc,2008,130(31):10150−10164. doi: 10.1021/ja7100399 [22] FAN W B, FAN B B, SHEN X H, LI J F, WU P, KUBOTA Y, TATSUMI T. Effect of ammonium salts on the synthesis and catalytic properties of TS-1[J]. Microporous Mesoporous Mater,2009,122(1/3):301−308. doi: 10.1016/j.micromeso.2009.03.018 [23] SHAKERI M, DEHGHANPOUR S B. Rational synthesis of TS-1 zeolite to direct both particle size and framework Ti in favor of enhanced catalytic performance[J]. Microporous Mesoporous Mater,2020,298:110066. doi: 10.1016/j.micromeso.2020.110066 [24] SHEN X H, WANG J J, LIU M Q, LI M Z, LU J J. Preparation of the hierarchical Ti-Rich TS-1 via TritonX-100-Assisted synthetic strategy for the direct oxidation of benzene[J]. Catal Lett,2019,149(9):2586−2596. doi: 10.1007/s10562-019-02735-5 [25] TREACY M M J. Collection of Simulated Xrd Powder Patterns for Zeolites[M]. 5th ed. Amsterdam: Elsevier Science, 2007, 276. [26] BURKETT S L, DAVIS M E. Mechanism of structure direction in the synthesis of Si-ZSM-5: an investigation by intermolecular 1H-29Si CP MAS NMR[J]. J Phys Chem,1994,98(17):4647−4653. doi: 10.1021/j100068a027 [27] BURKETT S L, DAVIS M E. Mechanisms of structure direction in the synthesis of pure-silica zeolites. 1. synthesis of TPA/Si-ZSM-5[J]. Chem Mater,1995,7(5):920−928. doi: 10.1021/cm00053a017 [28] THANGARAJ A, KUMAR R, MIRAJKAR S P, RATNASAMY P. Catalytic properties of crystalline titanium silicalites i. synthesis and characterization of titanium-rich zeolites with MFI structure[J]. J Catal,1991,130:1−8. doi: 10.1016/0021-9517(91)90086-J [29] LI C, XIONG G, LIU J K, YING P L, XIN Q, FENG Z C. Identifying framework titanium in TS-1 zeolite by UV resonance raman spectroscopy[J]. J Phys Chem B,2001,105(15):2993−2997. doi: 10.1021/jp0042359 [30] SHAKERI M, DEHGHANPOUR S B. Preparation of efficient TS-1 with small particle size and enhanced framework Ti[J]. ChemistrySelect,2019,4(16):4771−4774. doi: 10.1002/slct.201900457 [31] LI C, XIONG G, XIN Q, LIU J K, YING P L, FENG Z C, LI J, YANG W B, WANG Y Z, WANG G R, LIU X Y, LIN M, WANG X Q, MIN E Z. UV resonance raman spectroscopic identification of titanium atoms in the framework of TS-1 zeolite[J]. Angew Chem Int Ed,1999,38(15):2220−2221. doi: 10.1002/(SICI)1521-3773(19990802)38:15<2220::AID-ANIE2220>3.0.CO;2-G [32] ASTORINO E, PERI J B, WILLEY R J, BUSCA G. Spectroscopic characterization of silicalite-1 and titanium silicalite-1[J]. J Catal,1995,157(2):482−500. doi: 10.1006/jcat.1995.1313 [33] SU J, XIONG G, ZHOU J C, LIU W H, ZHOU D H, WANG G R, WANG X S, GUO H C.Amorphous Ti species in titanium silicalite-1: Structural features, chemical properties, and inactivation with sulfosalt[J]. J Catal, 2012, 288: 1−7. [34] LANGERAME F, SALVI A M, SILLETTI M, MORETTI G. XPS characterization of a synthetic Ti-containing MFI zeolite framework: the titanosilicalites, TS-1[J]. Surf Interface Anal,2010,40(3/4):695−699. [35] 夏清华, 王公慰, 应慕良, 曹国英, 郑禄彬. 钛-硅沸石的结构表征及其催化性能[J]. 催化学报,1994,15(2):109−114.XIA Qing-hua, WANG Gong-wei, CAO Guo-ying, ZHENG Lu-bin. Structure characterization and catalytic performance of titanium silicalite zeolites[J]. Chin J Catal,1994,15(2):109−114. [36] XU W J, ZHANG T J, Bai R S, ZHANG P, YU J H. A one-step rapid synthesis of TS-1 zeolites with highly catalytically active mononuclear TiO6 species[J]. J Mater Chem A,2020,8(19):9677−9683. doi: 10.1039/C9TA13851J [37] BAI R S, NAVARRO M T, SONG Y, ZHANG T J, ZOU Y C, FENG Z C, ZHANG P, CORMA A, YU J H. Titanosilicate zeolite precursors for highly efficient oxidation reactions[J]. Chem Sci,2020,11(45):12341−12349. doi: 10.1039/D0SC04603E [38] 高焕新, 卢文奎, 陈庆龄. 钛硅分子筛TS-1催化氯丙烯环氧化反应动力学研究[J]. 催化学报,2002,23(1):3−8. doi: 10.3321/j.issn:0253-9837.2002.01.002GAO Huan-xin, LU Wen-kui, CHEN Qing-ling. Reaction kinetics of epoxidation of allyl chloride with hydrogen peroxide catalyzed by titanium Silicalite-1[J]. Chin J Catal,2002,23(1):3−8. doi: 10.3321/j.issn:0253-9837.2002.01.002