Five kinds of rare earth La-modified X-zeolite catalysts were prepared by liquid-phase ion exchange procedures with different time of ion exchange and calcination. Their catalytic performance were tested in isobutane/butene with a continuously operation fixed bed reactor. The crystallographic structure of catalysts were characterized by XRD, and the acidity were examined by NH3-TPD and infrared spectroscopy for pyridine adsorbed (Py-IR). The results showed that the preparation process had significant effects on the structure and properties of the catalyst. The structure of zeolites did not change fundamentally after the introduction of lanthanum, but their crystallinity decreased significantly. The distribution of acid sites depend strongly on the lanthanum ion exchange procedures, especially the rehydration process of zeolite after the first calcined for ion exchange, which could significantly improve the strong B acid capacity of zeolite. The introduction of La3+ could increase the acidic sites of the zeolite, enhance the strong B acid, and reduce L acid of the catalyst. Among the five catalysts, catalytic performance of 2+3 when its ion exchange twice before calcination and thrice after calcinations occurred and it was calcinated again exhibited best, the initial conversion rate of butene was 89.94% and the yield of C8 products was 66.71%. This is because the enhancement of acidity due to the modification of La facilitate the hydrogen transfer, which is the determine step of alkylation, resulting in inhibiting the side reactions. The reaction temperature and feeding speed have strong effects on alkylation catalyzed over the La-modified X-zeolite. C5?C7 products increased from 9.64% to 36.74% when the reaction temperature was increased from 80℃ to 100℃. When the feed rate of butene was reduced from 0.1 h?1 to 0.05 h?1, the oligomeric generated C9+ products increased from 7.2% to 31%.
[1] Querini C A. Isobutane/butene alkylation: regeneration of solid acid catalysts [J]. Catalysis Today, 2000, 62(2-3): 135-143.
[2] Zhang H H, Liu R X，Zhang R R, Huo F, Yang Z Q, He B, Zhang S J, Wang Y J. Stability, acidity and interaction properties of [Bmim][SbF6] coupled with concentrated sulfuric acid [J]. Science China-Chemistry. 2017, 60(9): 1243-1249.
[3] Zhang H H, Liu R X, Yang Z Q, Huo F, Zhang R R, Li Z H, Zhang S J, Wang Y J. Alkylation of isobutane/butene promoted by fluoride-containing ionic liquids [J]. Fuel, 2018, 211: 233-240.
[4] Stocker M, Mostad H, Rorvik T. Isobutane/2-butene alkylation on faujasite type zeolites (H EMT and H FAU) [J]. Applied Catalysis A:General, 1994, 28(2-4):203-209.
[5] 吴梅，马忠庭，张海兵. 以分子筛催化剂催化的C4烷基化反应研究进展 [J]. 炼油与化工, 2012, 23(1): 1-3.
Wu M, Ma Z T, Zhang H B. Research progress of C4 alkylation reaction catalyzed with molecular sieves [J]. Refining and Chemical Industry, 2012, 23(1): 1-3.
[6] Feller A, Guzman A, Lercher J A, et al. On the mechanism of catalyzed isobutane/butene alkylation by zeolites [J]. Journal of Catalysis, 2004, 224(1): 80-93.
[7] 李健，李永祥. 分子筛在异丁烷/丁烯烷基化中的应用研究进展 [J]. 化工进展, 2013, 32(s1): 122-126.
Li J, Li Y X. Advances in isobutane/butene alkylation used zeolite [J]. Chemical Industry and Engineering Progress, 2013, 32: 122-126.
[8] Corma A, Martinez A, Martinez C, et al. Isobutane/2-butene alkylation on MCM-22 catalyst. Influence of zeolite structure and acidity on activity and selectivity [J]. Catalysis letters, 1994, 28(2-4): 187-201.
[9] Loenders R, Jacobs P A, Martens J A. Alkylation of isobutane with 1-butene on zeolite beta [J]. Journal of Catalysis, 1998, 176(2): 545-551.
[10] Garwood W E. Paraffin-olefin alkylation over a crystalline aluminosilicate [J]. Journal of Catalysis, 1968, 11(2): 175-177.
[11] Kirsch F W, Barmby D S, POTTS J D, et al. GD zeolite and hydrocarbon conversion process with GD zeolite catalyst [P], USP 3624173, 1971.
[12] Klingmann R, Josl R, Weitkamp J, et al. Hydrogenative regeneration of a Pt/La-Y zeolite catalyst deactivated in the isobutane/n-butene alkylation [J]. Applied Catalysis A: General, 2005, 281(1-2): 215-223.
[13] Guzma A, Feller A, Lercher J A, et al. On the formation of the acid sites in lanthanum exchanged X zeolites used for isobutane/cis-2-butene alkylation [J]. Microporous and Mesoporous Materials, 2005, 83(1-3): 309-318.
[14] Ward J W. Hydroxyl groups on hydrogen Y zeolite [J]. The Journal of Physical Chemistry, 1969, 73(6): 2086-2088.
[15] Sievers C, Olindo R, Lercher J A, et al. Comparison of zeolites LaX and LaY as catalysts for isobutane/2-butene alkylation [J]. Applied Catalysis A: General, 2008, 336(1-2): 89-100.
[16] Jin D F, Zhu B, Hou Z Y, et al. Dimethyl ether synthesis via methanol and syngas over rare earth metals modified zeolite Y and dual Cu–Mn–Zn catalysts [J]. Fuel, 2007, 86(17-18): 2707-2713.
[17] Du X H, Gao X H, Zhang H T, et al. Effect of cation location on the hydrothermal stability of rare earth-exchanged Y zeolites [J]. Catalysis Communications, 2013, 35(35): 17-22.
[18] Schumler F, Shi H, Lercher J A, et al. Enhancement of Dehydrogenation and Hydride Transfer by La3+ Cations in Zeolites during Acid Catalyzed Alkane Reactions [J]. ACS Catalysis, 2014, 4(6): 1743-1752.
[19] 于善青，龙军，等. 稀土离子调变Y型分子筛结构稳定性和酸性的机制 [J]. 物理化学学报, 2011, 27(11): 2528-2534.
Yu S Q, Long J, et al. Mechanism of Rare Earth Cations on the Stability and Acidity of Y Zeolites [J]. Acta Phys.-Chim Sin., 2011, 27(11): 2528-2534.
[20] 张探，周灵萍，田辉平. 稀土交换量对Y型分子筛结晶度测定值的影响 [J]. 石油炼制与化工, 2011, 42(4): 40-44.
Zhang T, Zhou L P, Tian H P. Effect of Rare Earth Content on the Crystallinity of Zeolite by XRD Analysis [J]. Petroleum Processing and Petrochemicals, 2011, 42(4): 40-44.
[21] 孙敏，贺振富. 稀土改性Y型分子筛的酸性研究 [J]. 石油炼制与化工, 2011, 42(5): 36-39.
Sun M, He Z F. Research on the Acidic Properties of Rare Earth Modified Zeolite Y [J]. Petroleum Processing and Petrochemicals, 2011, 42(5): 36-39.
[22] Costa B D, Querini C A. Isobutane alkylation with solid catalysts based on beta zeolite [J]. Applied Catalysis A: General, 2010, 385(1-2): 144-152.
[23] Koklin A E, Chan V M K, Bogdan V I. Conversion of isobutane-butenes mixtures on H-USY and SO4 2? /ZrO2 catalysts under supercritical conditions: Isobutane alkylation and butenes oligomerization [J]. Russian Journal of Physical Chemistry B, 2015, 8(8): 991-998.
[24] 王留阳，赵国英，任保增，等.酸性催化剂的酸性表征研究进展 [J]. 过程工程学报, 2017, 17(6): 1119-1126.
Wang L Y, Zhao G Y, Ren B Z, et al. Research Advances in Acidity Characterization of Acid Catalysts (in Chinese) [J]. Chin. J. Process Eng., 2017, 17(6): 1119-1126.
[25] Emeis C A. Determination of Integrated Molar Extinction Coefficients for Infrared Absorption Bands of Pyridine Adsorbed on Solid Acid Catalysts [J]. Journal of Catalysis, 1993, 141(2): 347-354.
[26] 彭凯，张成喜，李永祥. 异丁烷_丁烯烷基化固体酸催化剂的再生方法研究进展 [J]. 化工进展, 2015, 34(9): 3296-3302.
Peng K, Zhang C X, Li Y X. Advances in regeneration methods of solid acid catalyst for isobutane/butene alkylation [J]. Chemical Industry and Engineering Progress , 2015, 34(9): 3296-3302．
[27] Patrylak K I, Patrylak L K, Pertko O P, et al. Coke Alternate Movement in Faujasite Based Catalysts Deactivated from Butene Alkylation [J]. Current Catalysis, 2016, 5(2): 108-115.
[28] Hamzehlouyan T, Kazemeini M, Khorasheh F. Modeling of catalyst deactivation in zeolite-catalyzed alkylation of isobutane with 2-butene [J]. Chemical Engineering Science, 2010, 65(2): 645-650.
[29] Sievers C, Zuazo I, Guzman A, et al. Stages of aging and deactivation of zeolite LaX in isobutane/2-butene alkylation [J]. Journal of Catalysis, 2007, 246(2): 315-324.
[30] Guzman A, Zuazo I, Lercher J A, et al. Influence of the activation temperature on the physicochemical properties and catalytic activity of La-X zeolites for isobutane/cis-2-butene alkylation [J]. Microporous and Mesoporous Materials, 2006, 97(1-3): 49-57.
[31] Martinez A. Alkylation-Heterogeneous [J]. Encyclopedia of Catalysis, 2002, 1-63.
