钛硅分子筛催化剂的研究进展

Research progress of titanium silicalite catalys tZhangxiaoming Zhangzhaorong Soujiquan Lishuben(Lanzhou Institute of Chemical Physics fine petrochemical intermediates National Engineering Research Center, Lanzhou 730000)The role of titanium catalyst in the oxidation reaction of organic compounds is well known [1, 2]. Introduced in the molecular sieve framework due to the molecular sieve having a regular pore structure and large specific surface area characteristics, hetero atom, having an oxidation-reduction ability to preparenovel catalytic oxidation catalyst, has been more interesting subject in 1983 ENI [3] the T ar amasso its collaborators first successful synthesis of the titanium-containing zeolite catalyst of TS-1, a subsequent study found, Tammonia oxidation [7] S-1 with H2O2 aqueous solution as oxidant and the oxidation reaction of a series of organic compounds, such as olefin epoxidation [4], the aromatic hydrocarbon ring hydroxylation [5, 6], ketone, alkane oxidation[8, 9] and the alcohol oxidation [10] and so the process has a unique shape-selective catalytic function as compared with other types of catalytic systems, the system (1) the mild reaction conditions (atmospheric pressure, 0 - 100 ° C); (2) the unique function of the shape-selective catalytic oxidation; (3) environmental friendliness.TS-1 has been very limited because the aperture is only about 0. 55 nm, and its range of applications where the aerodynamic diameter is greater than 0.60 nm substrate molecules can not enter within its pores without reactivity. Orderovercome this limitation, the type of catalyst to get a wider range of applications, the majority of scientists have successfully synthesized T S-2 [11], Ti-Beta [12] and a series of large aperture zeolite catalysts.In recent years, with the development of the petroleum refining and fine petrochemical technology requires the use of some reorganization of the oil to be effective. M41S [13, 14], HMS [15] and MSU [16] series of mesoporous molecular sieves Tiheteroatom derivatives T i-MCM-41 [17], Ti-MCM-48 [18], Ti-HMS [19, 20] and of Ti-the MSU [16] emerged, the latter in the selective oxidation of organic compoundsshowed higher catalytic activity.This paper reviews the recent years, the progress made in terms of microporous and mesoporous titanium silicalite catalyst preparation, characterization, and catalytic reaction.T S-1 is first synthesized, and also so far been studied most, and more thoroughly of a class of titanium silicalite catalyst. T S-1 is a Silicalite-1 isomorphously substituted derivatives thereof, having the MFI structure. TS- work and the results achieved many comments have been reported [10, 21 - 24] here only a brief overview of the TS-1 preparation, characterization, and their corresponding catalytic reaction.The classical method of preparing a zeolite catalyst is a hydrothermal synthesis method in the the earliest patent literature, Tar amasso [3] reported two preparation T S-1 The method of one is tetraethyl orthosilicate (T EOS) and tetraethylammonium n-titanate (TEOT) as silica source and a titanium source, and tetrapropyl ammonium hydroxide (TPA OH) as templating agent;other is a silica sol as a silicon source, and to dissolve in H2O2 the titanate as titanium source TPAOH templating agent in addition to the hydrothermal synthesis method, the TS -1 can also be obtained by the method of secondary synthesis TiCl4 and dealumination of ZSM-5 for vapor phase reaction, to give with hydrothermal synthesis method is similar to the structure [25], but this method is easy to cause anatase. Huanxin et al [26] for the titanium source, TEOS as a silicon source, and succeeded in synthesizing a T S-1 to T iCl3 The same catalytic activity, with the same reported in the literature, and the process can be effectively prevented from generation of anatase In addition, Tuel and T aarit, continuous coverage positive ions with phosphorus [27], 1, 6 - hexamethylene diammonium ion (Di -TPA) [28], tetraethyl ammonium hydroxide (TEAOH) / T PAOH and T EAOH / tetrabutyl ammonium hydroxide (T BA OH) [29] as a template to prepare T S-1 process. described using different Preparation of Template T S-1 is likely the. Preparation of Titanium Silicalite reagent over Na +, K + and other alkali metal ions of the concentration should be sufficiently low, because the alkali metal ions will hinder the titanium atom in the molecular sieve framework embedded; another the one hand, to prevent the preparation process difficult to dissolve the anatase anatase formation will lead to subsequent reaction of H2O2 decomposition and reduce the catalytic activity in order to prevent the generation of anatase, the preparation process should be vigorously stirred, so that titanium source in the silicon source is highly fragmented., Thangaraj, [7] the slower rate of hydrolysis the of tetrabutylammonium positive titanate (TBOT) Alternate TEOT, with anhydrous isopropyl alcohol as a co-solvent, and achieved good effect.TS-1 zeolite catalyst unique shape-selective catalytic oxidation function, undoubtedly has a direct relationship with the skeleton of T i (Ⅳ) Therefore, the focus of such zeolite characterization is to determine the existence of T i (Ⅳ) in the molecular sieveits ligand environment. characterization of TS-1, except for routine characterization of X-ray diffraction (XRD), N2 adsorption / desorption method, Fourier transform infrared spectroscopy (FT-IR) 29Si magic anglespinning nuclear magnetic resonance spectroscopy(29Si-MAS-NMR), diffuse reflectance UV - visible spectrum (DR UVVis), X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure analysis (XANES) and other technologies exist in the form of tetrahedral coordination T i (Ⅳ) provided the basis forAccording to the naming of IUPAC [40], the aperture between 2 - 50 nm molecular sieves for mesoporous molecular sieves. 1990s, class zeolite inorganic materials separation, ion exchange and catalytic disciplines one of the hot to longchain surfactants as templating agent, have been successfully synthesized M41S [13, 14], HMS [15] and MSU [16] and a series of mesoporous molecular sieves. formation mechanism of the pore structure of mesoporous molecular sieve research has been reported[41 - 46] At the sametime, Ti [17 - 20], V [47], Zr [48], Mn [49] and Cr [50] with the redox ability of transition metal atoms into mesoporous molecular sieveskeleton structure, get a lot of new catalysts for the preparation of fine chemicals which T i atom isomorphous substitution in the hole titanium silicalite has important significance of theoretical research and industrial application value.The Gont ier and T uel [20] also Press T anev to method prepared Ti-HMS, and preparation process of various factors such as the proportion of T iO2 / SiO2, isopropanol, surface active agent chain length, characteristic of the titanium source and of Surf / SiO2 system. found that in the preparation process, when the two reagents is mixed for 15 min, the resulting product had with Hex ago nal various characteristics of most of Surf / SiO2 the best ratio of 0.3 increase this proportion of the aperture increases, but the specific surface area and adsorption capacity is greatly reduced.Reviewed above on the synthesis, characterization and catalytic oxidation properties of titanium silicalite and mesoporous molecular sieves prepared its heteroatom derivatives can be seen, the titanium silicalite as a new type of selective oxidation catalyst demandis very important to the increasing volume of the preparation of fine chemicals. especially in recent years, the success of a series of mesoporous molecular sieves synthesis and application, making the range of applications greatly broaden the field has attracted more and more attention of researchersbut we should also see that there are still many problems in the field, such as the titanium silicalite catalytic reaction mechanism, the formation mechanism of mesoporous molecular sieves and skeleton in the presence of T i (Ⅳ) way for further exploration of these issuesand research will become a research focus in the coming period.钛硅分子筛催化剂的研究进展张小明张兆荣索继栓李树本( 中国科学院兰州化学物理研究所精细石油化工中间体国家工程研究中心兰州730000) 含钛催化剂在有机化合物氧化反应中的作用是众所周知的[ 1, 2] . 由于分子筛具有规整的孔道结构和较大的比表面积等特点, 在分子筛骨架中引入具有氧化还原能力的杂原子, 以制备新型的催化氧化催化剂, 一直是人们比较感兴趣的课题. 1983 年ENI[ 3] 的T ar amasso 及其合作者首次成功地合成了含钛的分子筛催化剂TS-1. 随后的研究发现, T S-1 在以H2O2 水溶液为氧化剂的一系列有机化合物的氧化反应, 如烯烃的环氧化[ 4]、芳烃环的羟基化[ 5, 6] 、酮的氨氧化[ 7] 、烷烃的氧化[ 8, 9] 及醇的氧化[ 10] 等过程中有独特的择形催化功能. 同其他类型的催化体系相比较,该体系有( 1)反应条件温和( 常压, 0- 100℃);( 2) 独特的择形催化氧化功能;( 3)环境友好等优点。