钛硅分子筛催化剂的研究进展

1、Research progress of titanium silicalite catalysZhangxiaoming 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

2、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 i

3、n 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 epoxidat

4、ion 4, the aromatic hydrocarbon ring hydroxylation 5, 6, ketone, alkane oxidation8, 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,

5、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

6、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 developmen

7、t 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

8、 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 als

9、o 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 th

10、e 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

11、 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 hydroth

12、ermal 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 titaniu

13、m 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 pho

14、sphorus 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 S

15、ilicalite 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 anat

16、ase 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 sl

17、ower 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

18、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 infrare

19、d 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 (XA

20、NES) and other technologies exist in the form of tetrahedral coordination T i (IV) providedthe 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 catalyti

21、c 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 reported41 - 46 At the s

22、ame time, 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 importan

23、t significance of theoretical research and industrial application value.The Gont ier and T uel 20 also Press T anev to method prepared T i-HMS, and preparation process of various factors such as the proportion of T iO2 / SiO2, isopropanol, surface active agent chain length, characteristic of the tit

24、anium 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 specif

25、ic 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 o

26、xidation 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 mor

27、e 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 issues

28、and 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.

29、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。TS-1 由于孔径只有0. 55 nm 左右 , 而使其应用范围受到了很大的限制. 凡动力学直径大于0. 60 nm 的底物分子因不能进入其孔道内部而无反应活性. 为了克服这一局限性, 使该类催化剂能得到更为广泛的应用, 广

30、大科研工作者相继成功地合成了T S-2 11 、 Ti-Beta 12 等一系列孔径较大的分子筛催化剂。近年来 , 随着石油炼制及精细石油化工技术的发展, 要求对一些重组分油加以有效利用. M41S 13, 14、 HMS 15 及 MSU 16 等系列中孔分子筛及其Ti 杂原子衍生物T i-MCM-41 17、 Ti-MCM-48 18 、 Ti-HMS 19, 20 和Ti-MSU 16 等应运而生, 后者在有机化合物选择氧化中表现出较高的催化活性。本文综述了近几年在微孔及中孔钛硅分子筛催化剂的制备、表征及催化反应等方面所取得的进展。T S-1 是最早合成的、也是迄今为止人们研究得最多且比

31、较彻底的一类钛硅分子筛催化剂. T S-1 是 Silicalite-1 的同晶取代衍生物, 具有 MFI 的结构 .关于 TS-1 的工作和所取得的成果已经有许多评述见诸报道 10, 21- 24 . 这里仅就TS-1的制备、表征及其相应的催化反应等方面作一简要的概述。制备分子筛催化剂的经典方法是水热合成法. 在最早的专利文献中, Taramasso 等 3 报道了两种制备T S-1 的方法 . 一种是以四乙基正硅酸酯( T EOS)和四乙基正钛酸酯( TEOT ) 为硅源和钛源, 以四丙基氢氧化铵( TPA OH) 为模板剂；另一种是以硅溶胶为硅源,以溶解于H2O2中的钛酸酯为钛源，用TP

32、AOH 做模板剂. 除了水热合成法之外, TS -1 也可以通过二次合成的方法得到. 以TiCl4和脱铝的ZSM-5s行气相反应，得到了与水热合成法类似的结构25. 但这种方法易于导致产生锐钛矿. 高焕新等人 26 以 T iCl3 为钛源 , TEOS 为硅源 , 成功地合成了T S-1, 具有同文献报道同样的催化活性, 并且该过程可以有效地防止锐钛矿的产生. 另外 , Tuel 和 T aarit 连续报道了用磷正离子 27 、 1, 6-己二铵离子( Di-TPA) 28 、四乙基氢氧化铵( TEAOH)/ T PAOH及 T EAOH/ 四丁基氢氧化铵( T BA OH) 29 为模板

33、剂制备T S-1 的过程 . 说明用不同的模板剂制备T S-1 是可能的. 在钛硅分子筛的制备中, 试剂中 Na+ 、K+ 等碱金属离子的浓度应足够低, 因为碱金属离子会阻碍钛原子在分子筛骨架中的嵌入; 另一方面, 要防止制备过程中产生难溶解的锐钛矿. 锐钛矿的形成会导致后续反应中H2O2的分解而降低催化活性.为了防止锐钛矿的产生,制备过 程中应该激烈搅拌, 使钛源在硅源中高度分散. 另外 , Thangaraj 等 7 以水解速度较慢的四丁基正钛酸酯( TBOT ) 替代 TEOT , 用无水异丙醇作为共溶剂,取得了较好的效果。TS-1分子筛催化剂独特的择形催化氧化功能,无疑与骨架中的T i( IV) 有着直接的关系.因此，该