MCM-48-like large mesoporous silicas with t

为了：With a view to doing sth. (With a view to avoiding the inhomogeneous dispersion of rare-earth complexes within the silica matrix)with the aim of …(we have also investigated the preparation of cyclam-containing hybrid materials in the presence of a surfactant template with the aim of locating the cyclam moieties inside the framework.)In the goal to …（In the goal to extend the range of properties of these materials)In an effort to …(In an effort to produce new propene polymerisation catalyst systems which yield high molecular mass polypropylene with even greater specific isotacticities we have investigated the catalytic activity of mesoporous silicates with included chiral ansa-metallocenes.)首次：a original route to＋n. (a original route to Eu3+ containing hybrid materials.)相应的：the corresponding materials副产物：byproduct场发射扫描电镜：field-emission scanning electron microscopy平均半径：mean diameter (with 100μm mean diameter)就…而言：with respect to… (The preparation of mesoporous silicas which exhibit good hydrothermal stability (in hot water and under steaming conditions) is one ofthe most important requirements with respect to their use.)除了…之外：in addition to… (another V(V) species in distorted octahedral coordination starts to appear in addition to V10O286- for high vanadium content of V/(V+ Si) ) 48%.)Aside from… (Aside from a thicker pore wall, the framework crosslinkingwas higher than for conventional MCM-41, as indicated by 29Si MASNMR.)除了…：Except for… (Except for a slight decrease in the d spacing, compaction at 185 MPa does not have any significant effect on the XRD pattern of AlMCM4.)except that… (The experimental procedures were exactly as described aboveexcept that during the secondary synthesis the heating at 150 °C was performedfor 96, 140 or 168 h.)save for… (Incorporation of organic functional groups (MPTMS) inside thestructures appeared to have little influence on the structure and morphology ofthe mesostructures, save for slight lattice and pore diameter contractions uponincreasing organosilane group loading.)定向生长：The phased growth产生…：gi ve rise to… (The latter method gives rise to MCM-41 materials of excellent quality, but seems to be less convenient, since the structure directing agentsrequired are not readily available and need to be synthesized.)生物活性分子：bioactive molecules范例：paradigm剧烈地：vigorously代替…：in place of… (by using n-butanol as co-surfactant in place of ethanol)本身的，固有的：intrinsic摩尔比：a liquid/solid ratio of 50; an olefin/TBHP molar ratio of 4好的结果：a positive effect on…有…的结构：with…architecture (Organically-modified mesoporous silica spheres with MCM-41 architecture)with… type of structure (A series of new mesoporous silica materials withMCM-41 type of structure containing a homogeneous layer of organicfunctional groups inside the pores was prepared using a co-condensationmethod under low surfactant concentration condition.)残留的：residual红外：Fourier transform infrared spectroscopy (FTIR),因素：factor数量级的：order-of–magnitude (order-of–magnitude enhancements)与…一致：In accord with…(In accord with the tetrahedral siting of aluminum, the Br¢nsted acidity of these steamstable mesostructures was verified throughcumene cracking experiments.)Consistent with… (Consistent with elemental analysis, an increase in the Alconcentration on the framework walls was observed by XPS analysis.)be identical to… (A 150 °C onset decomposition temperature is consistentlyobserved for externally adsorbed on MCM-41 and is identical to thatobserved for pure 1.)be consistent with… (This is consistent with the incorporation of increasingamounts tetrahedral Al into the framework and is in part due to the longerAl–O bond length compared to the Si–O bond.)be in line with…(This is in line with the notion that the acid-mademesoporous materials are, in general, less stable than those synthesized viathe alkaline route.)50% 的Si被官能化：50% organo-functionalization of the framework silicon sites部分地：in part (We attribute the unique hydrothermal stability of Al-MSU-S at least in part to the retention of a zeolite-like connectivity of AlO4 and SiO4 tetrahedraupon assembling the zeolite seeds into a mesostructure.)在…的支持下：in support of…(in support of the importance of a zeolite-like connectivity)在…的基础上：On the basis of… (On the basis of the relationship between 27Al chemical shift and the mean bond angle in framework aluminosilicates, the meanAl-O-Si angle is substantially smaller (by~8°) in Al-MSU-S than inpreviously reported forms of Al-MCM-41.)比…好：be superior over…(the catalytic activities of the new materials are superior over conventional materials such as Al-MCM-41 and Al-SBA-15.)outperform (In the alkylation and isomerization reactions, the hybrid catalystsignificantly outperformed some of the alternative solid resin catalystscurrently used, e.g., Nafion resin NR 50 and Amberlyst-15.)归因于…：be assigned that…(This phenomenon is also assigned that the preformed L nanoclusters are fixed in the wall of mesoporous aluminosilicates by theassembly of preformed zeolite L precursors with surfactant micelle.)be attributable to…(It is clear that the improved hydrothermal stability ofMSUG, like SBA-15, is attributable in large part to the thicker frameworkwalls (2.5 nm) in comparison to MCM-41, KIT-1, and SBA-3.)be attributed to… (The instability of these structures has been attributed inpart to the thinness and incomplete crosslinking of the pore walls)be due to…(It was concluded that the increased acidity of hydrothermallytreated CAH5 and CAP10 was due to an increase in the Al/Si ratio in theframework.)在…之中：Of the three forms of polypropene, the highly ordered, high molecular mass isotactic form is the most important.研究热点：active area of research (The application of acid zeolites for the production of fine chemicals is currently an active area of research)所有的样品：all of the samples控温装置：temperature controller压力表：pressure gauge更具体的说：More specifically ( The TDS process consists of a direct displacement of quaternary alkylammonium surfactant cation by desired silyl group, whichin fact is the replacement of electrostatic interactions at theorganic-inorganic interface by covalent bonds. More specifically, theinteracting pairs ≡Si-O-∙∙∙S+ (≡Si-O- is a unit of silicate oligomer and S+ isthe surfactant cation) are replaced by covalent bonds ≡Si-O-SiR`2R.)差异：discrepancy (However, a large discrepancy observed for the model with hydrolyzed side groups led us to the conclusion that alkoxy groups did not hydrolyze during the TDS process.)与…相关：correlate with…(The aforementioned changes correlate with the silane’s size.)be associated with…(In the published progress, several reasons areassociated with the enhanced hydrothermal stability of mesoporous silica.)be linked to…(We show that the amount of gold incorporated within thematerials is linked to the amount of mercapto functions and varies from 1.05to 16.1 wt %.)经验方法：empirical fashions. (However, because zeolite nucleation and growth is not well understood at a molecular level, most of the zeolite syntheses haveevolved according to empirical fashions.)倾向…：be inclined toward…(On the other hand, the product after 2 days of aging was inclined toward various distribution of Al in the framework, resulting in highSi/Al ratio.)不是…而是…：be not…but rather be… (Energy minimizations show that Na cations in site I are not at the centers of hexagonal prisms, but rather are in one oftwo symmetric SI sites displaced by about 0.6 Å along the [111]direction.)be not…but …(However, in contrast to zeolitic materials, thetemplates are not single organic molecules but liquidcrystallineself-assembled surfactant molecules. )受制于…：be subjected to…(nomeric bonded phases are subject to serious effects arising primarily from an unsatisfactory hydrolytic stability of the Si-O-Si-Clinkage, particularly under moderately acidic or slightly alkaline elutionconditions, and to a lesser extent from a relatively limited organic coverage.) 原则上：In principle (In principle, this method should provide not only a closer attachment and a denser coverage of organic functionalities but also a morehydrolytically stable bonded phase than that obtained by the correspondingSi-O-Si-C linkage)由…组成：be comprised of… (The purpose of our work is to explore the possibility of synthesizing zeolites that are comprised of intergrowths of cubic andhexagonal stackings of faujasite sheets and vary in the ratio ofcubic/hexagonal content.)突破：breakthrough (A recent breakthrough in improving both the hydrothermal stability and acidity of mesoporous aluminosilicates has been made through the use of nanoclustered zeolite seeds as frameworkprecursors)相当地：comparatively (It was concluded that the enhanced reactivity was a result of a comparatively short pore length and the more facile access of the reagents tothe acidic sites on the framework walls.)不大可能：It is unlikely that… (It is unlikely that the framework wall of MCM-41 can be transformed to a crystalline zeolite phase while still maintaining thehexagonal MCM-41 mesostructure.)如上所述：As stated above (As stated above, this band arises from the five-membered ring of vibrations of pentasil zeolite building subunits.)不同的时间：different periods of time (Structural changes caused by heating in water at 373 K for different periods of time(from 3 hours to 32 days) and bycalcination at 973-1273 K were investigated in order to assess thehydrothermal and thermal stability of FDU-1.)更重要的是…：What is more important is… (What is more important is that within themesoscale pore walls, micropore arrays with more or less periodicityare found (especially in those areas marked with circles or rectangles inFigures 7 and 8).More importantly (More importantly, there are significant structuraldifferences between MCM-41 and HMS silicas.)是合理的：it is logical to do… (Based on these observations it is logical to conclude that the small particles are (nonframework) amorphous silica which is removedduring refluxing (by dissolution), leaving the Al-grafted MCM-41framework (i.e., the large particle aggregates) intact.)最令人感兴趣的是：Of particular interest are (were) …(Of particular interest areAl-containing materials which may be used as solid acid catalysts.) 以…为代价：be at the expense of… (The increase in wall thickness is at the expense of pore diameter which reduces from 31.6 Å for PSMCM to 25.8 Å forAlMCM5.)对…敏感：be sensitive to … (It was also observed that the course of the hydrothermal restructuring was very sensitive to the experimental conditions, such astemperature.)为了比较：For comparison purposes (For comparison purposes we prepared Al-grafted amorphous silica using an ACH solution of Al concentration 0.24 mol/l andalso subjected PSMCM to alumination by 0.24 mol/l solutions of aluminiumchloride or sodium aluminate. )由于：Owing to… (Owing to the weak hydrogen bonding interactions, more than 90% of the neutral template can be recovered by a simple extraction procedure using ethanol as extracting solvent.)注意到…：be aware of… (We are aware of only two reports that provide some insight into the thermal stability of OMSs with cage-like pores at temperatures up to1123 K, and two reports on the hydrothermal stability of these materials,including the aforementioned work on FDU-1.)keep in mind that (However, we must keep in mind that the reaction itselfwill be very efficient if each absorbed photon can lead to the the formation ofa product molecule.)与…成正比：be proportional to… (Based on the pore size distribution shown in Figure 3, the amount of these structural defects formed is proportional to the amountof Al substituted in the sample.)与…成反比：be inversely proportional to… (The quantum yield for an ideal system, Φ, is proportional to the rate of the charge transfer processes and inverselyproportional to the sum of the charge transfer rate and the electron holerecombination rate)在…中占主导：be prevailing in… (Such a structure is prevailing in HCM, as can be found from the TEM images at lower magnification.)在图的右下角：in the bottom right corner of the image对…有害：be detrimental to…(Too high an ssembly temperature, however, is detrimental to mesostructure ormation through S0I0 assembly pathways.)对…有益：be conducive to… (The extremely high specific surface areas are conducive to high catalytic activity.)参看下文：vide infra参看上文：vide supra与…不同：be different from (The formation mechanism, composition, and properties are different from those of MCM-41 materials synthesized under alkalineconditions.)受到关注：be of concern (However, the stability of these materials in aqueous solutions is of concern.)一开始：at [in] the outset (It should be noted at the outset that a clean, uncoated silica surface is perfectly wetting, such that the contact angle of water on a fullyhydroxylated silica surface is zero.)有益于…：be conducive to… (Moreover, the large diameter and wormhole nature of the pore channels in these oxides are conducive to the formation of functionalmaterials in which the reactive species are highly dispersed within theframework and quantitatively accessible for reaction with adsorbatemolecules.)受…启发：be inspired by… (Our procedure was inspired by that described by Prouzet et al. leading to MSU silica by using tergitol as structure-directing agent.)不管…：regardless of whether… (Both titaniasupported catalysts exhibited higher activity for CO oxidation than the silica, supported ones, regardless of whetherthey were pre-treated in H2 or not.)irrespective of… (Platinum-free, white AMM-Ti exhibited only a very weakactivity, irrespective of excitation in the UV or visible spectral region.)这样就…：in such a way as…(However, the ligand-assisted templating technique provided a shielding effect by the inorganic components on the amphiphilehead groups in such a way as to favor selfassembly versus solubilization ofthe templating agents.)在其他条件相同时：Under otherwise the same conditions (Under otherwise the same conditions, a HMS-SO3H prepared via co-condensation gave 52%yield within 10 h, presumably because of its more open structure.) 被…影响，顺序是…：The light-conversion efficiency of the valence isomerization ofquadricyclene to its ring-opened isomer norbornadiene isinfluenced by the identity of the photocatalyst (TiO2, CdS, orZnO) and the solvent (CH2Cl2, CH3CN, or THF) used, with thechemical yield of ring-closed product decreasing in thefollowing order CdS > TiO2>ZnO and CH2Cl2> CH3CN >THF.大多：in most cases (The selective photofluorination of olefins, phosphines, andphosphites on illuminated TiO2in the presence of AgF inacetonitrile produces, in most cases, a single fluorinatedproduct.)服从于…：be amenable to (Toxic phosphorus-containing substrates are amenable tophotocatalyzed decomposition, ultimately to completelymineralized products, over illuminated semiconductorsuspensions.)因为：in the sense that (The excitation of a weak transition will not effectively induce aphotochemical reaction in the sense that few of the deliveredphotons will actually be absorbed.)与…竞争：In competition with…(In competition with charge transfer to adsorbedspecies is electron and hole recombination.)与…对照：in total contrast to… (Complete mineralization has been achieved in the caseof lanthanide oxide doped TiO2 photocatalysts in totalcontrast to the formation of intermediates in case ofnonmodified TiO2.)是…倍：be…times (The equilibrium dark adsorption of salicylic acid and t-cinnamic acidis ca.three times and two times higher, respectively, on thelanthanide oxide modified catalysts as compared to the nonmodifiedTiO2 catalyst.)不是这样：that was not the case (When an electrode coated with 1 was irradiated at different wavelengths in a standard photoelectrochemical cell, a photocurrentwas observed also in the visible region; that was not the case whenunmodified titania was employed.)不足：drawback（A serious drawback in such systems, however, is that the surfactants）研究目的：main objectives失重（热重分析）：weight-loss。

Grafted chromium13-membered dioxo-macrocyclic complex intoaminopropyl-based nanoporous SBA-15Aliakbar Tarlani a,n,Monika Joharian a,Khashayar Narimani a,Jacques Muzart b,Mahtab Fallah aa Inorganic Nanostructures and Catalysts Research Laboratory,Chemistry&Chemical Engineering Research Center of Iran,Pajoohesh Boulevard,km17,KarajHighway,Tehran14968-13151,Iranb Institut de Chimie Moléculaire de Reims,CNRS-Universitéde Reims Champagne-Ardenne,BP1039,51687Reims Cedex2,Francea r t i c l e i n f oArticle history:Received30January2013Received in revised form10April2013Accepted14April2013Available online2May2013Keywords:Mesoporous silicaHybride SBA-15NanoporeMacrocycleAlcoholysisEpoxidea b s t r a c tIn a new approach,chromium(III)tetraaza dioxo ligand was grafted onto functionalized SBA-15afterfour step reactions by using coordinating ability of anchored amino functionalized SBA-15.After thetermination of each step,the obtained product was characterized by FT-IR,low-angle X-ray diffraction(LA-XRD),N2adsorption–desorption isotherms(Brunauer–Emmett–Teller(BET)–Barret–Joyner–Halenda(BJH))and thermogravimetric analysis(TGA),and used as catalyst for the efficient and regioselectivealcoholysis of styrene oxide to2-alkoxy-1-phenylethanol product at ambient temperature.&2013Elsevier Inc.All rights reserved.1.IntroductionDiscovery of mesoporous silica with the high surface area,ordered channels and pore size distribution between2and50nm[1,2]attracted attention for heterogeneous catalysis[3],adsorbents[4]and medicine[5].MCM-41and SBA-15are the most well knownmolecular sieves with high similarity in structure and surface areaexcept the larger pores of the latter.However,the bare mesoporoussilicas suffer from their silanol group which limits their applicabilityin host–guest systems[6].To solve this problem,the functionaliza-tion of the mesoporous silica via a so called post-synthesis methodwith the variety of propyltrialkoxysilane derivatives((RO)3Si(CH2)3X,X¼Cl,NH2,SH or vinyl)or other functions is the mostcommonly used procedure[7–11].In addition to changing thehydrophobicity of the surface,let us immobilize a wide range ofthe catalysts to make a heterogeneous species.Among the men-tioned functions,amino functionalized hybride mesopore is con-sidered also as an adsorbent[12]and a catalyst[7,13,14].Macrocyclic ligand with organic framework contains heteroa-toms which can trap metallic ions[15].Nitrogen heteroatoms areimportant because they can lead to stable complexes via chelation.Among the aza macrocycles,the species with4nitrogen donors(N4)are the most interesting[16].Grafting such a ligand ispossible via the functionalisation of an NH unit with chloropro-pylsilane.In our previous work,heteropolyacids were immobilizedon amino functionalized MCM-41,silica-gel and fumed silica.Among silica materials,MCM-41showed the largest amine tosilica ratio which is attributed to its large surface area,but itshowed the least tendency for anchoring with heteropoly acids;this is attributed to the smaller pore size of MCM-41.Conse-quently,SBA-15with larger pore size than MCM-41was selectedas the support[17].In this report,dioxo13-membered N4macrocyclic ligand wasgrafted after modification of the surface by aminopropyl silane forthe only possible condensation between amino group and C¼Ogroup of the ligand.Chromium salts because of their wide applica-tions as homogeneous and heterogeneous catalysts[18,19]andtheir low costs were selected as species to incorporate into theligand.The prepared heterogeneous nanocatalyst has been appliedin the ring opening of styrene oxide by alcohols under ambienttemperature.2.Experimental2.1.Materials and measurementsPluronic P123with composition EO20PO70EO20and averagemolecular weight of5800was purchased from Aldrich.Tetraethylorthosilicate(TEOS),3-aminopropyltrimethoxysilane(APTMS),Contents lists available at SciVerse ScienceDirectjournal homepage:/locate/jsscJournal of Solid State Chemistry0022-4596/$-see front matter&2013Elsevier Inc.All rights reserved./10.1016/j.jssc.2013.04.027n Corresponding author.Fax:+982144580762.E-mail addresses:Tarlani@ccerci.ac.ir,aliakbartarlani@(A.Tarlani).Journal of Solid State Chemistry203(2013)255–259triethylene tetraamine,diethyl malonate,styrene oxide,methanol and ethanol were pro analysis grade and used without further puri fication.The physico-chemical characteristics were followed by Low-Angle XRD (Philips X 'Pert MPD),N 2adsorption –desorption isotherm and BJH pore size distribution plot (BELSORP-MINI)and TGA (Netzsch TG 209F1,from 20to 9001C with the heating rate of 51/min under air).2.2.Synthesis of aminopropyl functionalization of mesoporous silica (SBA-15-NH 2)Firstly SBA-15was prepared according to the procedure reported earlier [20].In a typical synthesis,4g of pluronic P123as template dissolved in 30g of deionized water and 120g of 2M HCl solution was added and stirred at 351C at 1400rpm.Then 8.5g of tetraethyl orthosilicate (TEOS)was added slowly.The obtained gel was continuously stirred for 20h at 351C.Then it aged in a stainless steel PTFE-lined autoclave at 901C for 24h.The solid product was filtered,washed with deionized water and dried at room temperature.Finally the white powder was calcined at 5001C for 6h with a heating rate of 11C/min to remove the surfactant.The aminopropyl functionalization of SBA-15has beencarried out according to the previous method [17]by adding 1.5g of 3-aminopropyltrimethoxysilane (APTMS)to 1.0g of SBA-15suspended in 50ml of toluene and re fluxing over-night.Then the solid was filtered and soxheleted with chloroform.2.3.Synthesis of 1,4,7,10-tetraazacyclotridecane-11,13-dione (TACTO2)Dioxomacrocyclic ligand was prepared by a slight modi fication of the reported method [21].Diethyl malonate (16.32g,0.1mol)and triethylene tetraamine (15.36g,0.1mol)dissolved in dry ethanol (900mL)was re fluxed for 5–6days.Then the volume was reduced to 200mL by rotary evaporation.The white crystals were formed in 2–3days and they were recrystallized 2times from 200mL absolute ethanol.The white crystals filtered and washed with cold ethanol and diethyl ether to obtain the pure ligand (mp 200–2051C).The structure of the ligand was con firmed by IR,1H NMR and 13C NMR.1,4,7,10-Tetraazacyclotridecane-11,13-dione,1H NMR (300MHz,DMSO-d6):1.76(m,2H,NH amine ),2.53(m,8H,CH 2NH amine CH 2),3.00(s,2H,NHCOCH 2),3.15(m,4H,NH amine CH 2CH 2NH amide ),8.03(t,2H,NH amide );13C NMR (300MHz,DMSO-d6):38.7,43.3,48.1,48.4,167.1;IR:3277,2846,1649,1581,1463,1429,;MS,m/z ¼215(M +1),214[M].2.4.Grafting of the ligand (SBA-15-NH 2-TACTO2)The synthetic route of SBA-NH 2-ligand is depicted in Scheme 1.In a typical synthesis,a mixture of ligand (0.5g),SBA-15-NH 2(1g)in toluene (50mL)was re fluxed overnight.The white solid was recovered by filtration and washed with toluene and dichlor-oethane.The excess ligand was removed by soxhelet extraction over chloroform for 8h and finally dried in oven.2.5.Chelating of chromium (III)(SBA-15-NH 2-TACTO2-Cr)Ligand-functional SBA-15(1g),CrCl 3∙6H 2O (0.5g)in ethanol (65mL)was re fluxed at 801C under stirring for 24h.The resulting solid was recovered by filtration and washed with ethanol.Then soxhelet extraction carried out over chloroform for 8h and finally dried in oven.Scheme 1.Preparation of the catalyst.A.Tarlani et al./Journal of Solid State Chemistry 203(2013)255–2592562.6.Styrene oxide ring openingIn a typical reaction,SBA-15-NH 2-TACTO2-Cr (0.005g)was added to the solution of styrene oxide (0.124g,1mmol)in methanol (5mL).The mixture was stirred till full conversion.After filtration through a short pad of alumina and evaporation,chro-matography on silica eluted with petroleum ether/ethyl acetate (85:15)of the residue led to the product which was identi fied from comparison of 1HNMR data with those of literature [22,23].3.Results and discussion 3.1.Catalyst characterizationPreparation of the catalyst is depicted in Scheme 1.TheFT-IR spectra of the samples in the range of 500–4000cm −1are depicted in Fig.1.The main features of the SBA-15spectra include a large broad band between 3200and3600cm −1which is attributed to O –H stretching νs,(OH)of the surface silanol group and the remaining physically adsorbed water molecules.The strong bands at about 1090and 806cm −1correspond to the νas,(Si –O –Si)and νs,(Si –O)respectively.Silanol groups of SBA-15give the char-acteristic band at 960cm −1.This peak declines by the reaction of silanol group with the ethoxy group of APTMS [24].In the FT-IR spectra of SBA-15-NH 2,the bands at 3298and 2939cm −1are related to NH and CH stretchings respectively [25].FT-IR spectra of the immobilized ligand on the surface obtained after soxhelating for 8h.The only way of the grafting is the condensation between amino group of SBA-15-NH 2and the C ¼O group of the ligand.Two ν(C ¼O)groups of the pure ligand appear at 1649cm −1.By anchor-ing the ligand,this bond shifts a little to lower frequency.It could be concluded that one of the C ¼O groups is replaced by the new bond.In the last step,Cr (III)inserts into the N4cycle because the new band of Cr –N emerges at 424cm −1.Besides,the bending band of NH is shifted from 1581to 1548cm −1which is in accordance with the literature [26].Such an effect should be observed for the stretching of 3277cm −1,which is not clear because of the presence of the wide band of the adsorbed water in that region.These lowest weight loss for bare SBA-15with the approximate amount of 5%which is mainly attributed to the loss of adsorbed water (Fig.2.).The TGA spectrum of functionalized SBA-15and grafted ligand showed 10%and 30%weight loss above 3501C that is attributed mainly to the decomposition of organic groups and emphasizes the successful accomplishment of the process and high loading of the ligand (about 37%)[27].According to TG Fig.3represents low angle XRD patterns of SBA-15and its modi fied samples.SBA-15shows intense diffraction peak of (100)at 2θ¼0.991and two secondary patterns corresponding to (110)and (200)re flections about 2θ¼21which are indicative of the hexagonal symmetry and textural uniformity of the mesopore.The low-angle XRD patterns of SBA-15-NH 2,SBA-15-NH 2-TACTO2and SBA-15-NH 2-TACTO2-Cr are similar to that of the parent SBA-15with a reduction in the intensity indicating modi fications inside the mesopore (Scheme 1).By modi fication of the pores,intensity of the peaks decreases and the sharp peak is shifted to higher angles which indicates the decrease of the surface area [17].Therefore,SBA-15structure remained intact under the conditions used for grafting.The porosity of samples (BJH and BET)was measured by N 2adsorption –desorption (Figs.4and 5).These isotherms are type IVwith characteristic behavior of the mesoporous materials as de fined by IUPAC [28].The sharp increase in the adsorption step between relative pressures (P/P 0)of 0.4–1indicated that the textural properties of SBA-15is kept over grafting by macrocyclic ligand with no signi ficant change in N 2sorption isotherm [20].The relative pressure (P /P 0)of the modi fied samples is shifted to a lower value in comparison to the parent materials,indicating decrease in speci fic surface area.BJH method showed narrow pore diameter distributions which is in agreement with good quality of SBA-15[29].Table 1provides characteristic parameters S BET and pore diameter of the species.The SBA-15has the maximum surfaceFig.1.FT-IR spectra of the parent SBA-15,grafted amine into the pores(SBA-15-NH 2),pure macrocyclic ligand before grafting (TACTO 2),grafted ligand on the surface (SBA-15-NH 2-TACTO 2)and chromium ion coordinated into the ligand (SBA-15-NH 2-TACTO 2-Cr).A.Tarlani et al./Journal of Solid State Chemistry 203(2013)255–259257area (878m 2g −1)which is reduced due to the functionalization of amine [17]and further the introduction of the ligand to 213and 147m 2g −1respectively.Decrease in the surface area can be attributed to the modi fication of the walls with organic moieties.The changes in the pore sizes occurred after modi fication of the parent SBA-15,but with a little irregularity which is also observed in other reports and is complex to elucidate [30–32].3.2.Catalyst activityIn the presence of the catalyst,the addition of methanol or ethanol to styrene oxide affords the corresponding 2-alkoxy-1-phenylethanol in high yield (Table 2;runs 1,2and 6)[22].Interestingly,no decrease of the ef ficiency was observed with the use of a recycled catalyst (Table 2;runs 3and 4)[33].Alcohols such as 1-propanol,2-propanol and allyl alcohol were assayedinFig.2.TGA curves of SBA-15,SBA-15-NH 2,SBA-15-NH 2-TACTO2and SBA-15-NH 2-TACTO2-Cr.Fig.3.Low-angle XRD patterns of SBA-15,SBA-15-NH 2,SBA-15-NH 2-TACTO2and SBA-15-NH 2-TACTO2-Cr.Fig. 4.N 2isotherms of SBA-15,SBA-15-NH 2,SBA-15-NH 2-TACTO2and SBA-15-NH 2-TACTO2-Cr.Table 1Surface properties of SBA-15,SBA-15-NH 2,SBA-15-NH 2-TACTO2and SBA-15-NH 2-TACTO2-Cr.SampleS BET (m 2g −1)Pore diameter a (nm)SBA-15787 3.12SBA-15-NH 2213 2.74SBA-15-NH 2-TACTO2147 2.74SBA-15-NH 2-TACTO2-Cr1452.41aPore diameters were calculated by the BJH method.Table 2Alcoholysis of styrene oxide a .RunCatalyst (mg)Time (h)SolventConversion (%)Yield (%)β-alkoxy alcohol 1024MeOH 0025(fresh) 2.5MeOH 100993(used)3MeOH 100994(re-used)3MeOH 100995018EtOH 006540EtOH 100100aConditions:Styrene oxide (1mmol),alcohol (5mL),roomtemperature.Fig.5.Pore size distribution (BJH)of SBA-15,SBA-15-NH 2,SBA-15-NH 2-TACTO2and SBA-15-NH 2-TACTO2-Cr.A.Tarlani et al./Journal of Solid State Chemistry 203(2013)255–259258this reaction but with no good response even at higher tempera-tures.Maybe the substrate has the favored site for the nucleophilic attack of methanol compared to the heavier alcohols.So methanol requires lower time for the reaction[34].Leaching test was carried out for the chromium ion.Atomic absorption spectroscopy showed no chromium leached from the support.FT-IR spectra of the reused catalyst were almost similar to those of the parent catalyst. These analyses prove the stability of the catalyst during the reaction[35].Scheme2represents the possible mechanism for this reaction. Nucleophilic attack of the alcohol in the presence of the active site of the catalyst leads to an intermediate whichfinally converts to regioselective2-alkoxy product[36].4.ConclusionThe grafting of dioxo tetraazamacrocyclic ligand onto the inner walls of amino functionalized SBA-15,made the strong host for Cr (III).The FT-IR spectroscopy indicated spectral features of modified samples.TGA analysis showed large quantity content of the ligand. 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MCM—48介孔分子筛的研究进展作者：周雅菲潘健民陈鹏来源：《中国科技纵横》2014年第04期【摘要】综述了MCM-48介孔分子筛的研究进展。

介绍了MCM-48的制备，表征，性能的研究及应用，最后从提高热稳定性，水热稳定性，催化性能及产率等方面提出了MCM-48的研究趋势。

【关键词】 MCM-48 制备性能综述自从1992年美国Mobil公司首次成功合成M41S系列介孔分子筛以来[1-2]，越来越多的人们对介孔分子筛的制备、表征、应用及其性能的提高进行了研究。

其在催化，吸附，分离和主客体化学等方面具有广泛的应用价值[3-4]。

MCM-48分子筛具有2-3nm的均一孔径和良好的长程有序性，特别是其三维孔道结构具有优良的传输性能，且不易造成吸附分子移动的障碍。

从吸附剂和催化剂角度着眼，MCM-48材料更具有发展潜力，因而备受关注[5]。

Wang[9，10，15]等人通过对其合成方法和结构的研究，对其水热稳定性及耐碱性能等方面进行了研究和改善。

1 MCM-48介孔分子筛的研究进展1.1 MCM-48介孔分子筛的制备MCM-48介孔分子筛的传统合成方法大多采用水热或高压合成，反应时间长，耗能大[1]，因此人们探索多种合成途径以缩短时间和节省能源[7]。

如Zhang[12]等人运用全微波技术合成高性能的MCM-48介孔分子筛。

采用真空浸渍法能较好的将酸性催化剂对甲苯磺酸引入MCM-48孔道内。

表征得所制得的中孔炭具有规整的三维孔道结构。

此外，还发现二次炭化有利于提高中孔炭的热稳定性。

微波合成法使用sH9402型微波炉，在一定的微波反应釜压力下辐射一段时间后，冷却，用去离子水洗涤并在离心机上离心沉降分离至pH1.2 MCM-48介孔分子筛的表征介孔分子筛的表征方法有X射线衍射（XRD）、透射电镜TEM（EDS）、FT—IR、N2吸附等。

可以通过观察XRD图谱中特征峰多少和强弱来判断分子筛结构的有序性、稳定性和结晶度。

美国大学生数学建模竞赛试题1996 American MCM Problems Problem AThe world's oceans contain an ambient noise field. Seismic disturbances, surface shipping, and marine mammals are sources that, in different frequency ranges,contribute to this field. We wish to consider how this ambient noise might be used to detect large moving objects, e.g., submarines located below the ocean surface. Assuming that a submarine makes no intrinsic noise, developa method for detecting the presence of a moving submarine, its size, and its direction of travel, using only information obtained by measuring changes to the ambient noise field. Begin with noise at one fixed frequency and amplitude.Problem BWhen determining the winner of a competition like the Mathematical Contest inModeling, there are generally a large number of papers to judge. Let's saythere are P=100 papers.A group of J judges is collected to accomplish thejudging. Funding for the contest constains both the number of judges that canbe obtained and amount of time that they can judge. For eample if P=100, thenJ=8 is typical.Ideally, each judge would read paper and rank-order them, but there are toomany papers for this. Instead, there will be a number of screening rounds inwhich each judge will read some number of papers and give them scores. Thensome selection scheme is used to reduce the number of papers under consideration: If the papers are rank-ordered, then the bottom 30% that eachjudge rank-orders could be rejected. Alternatively, if the judges do not rank-order, but instead give them numerical score (say, from 1 to 100),then all papers below some cut-off level could be rejected.The new pool of papers is then passed back to the judges, and the process is repeated.A concern is then the total number of papers that judge reads must besubstantially less than P. The process is stopped when there are only W papersleft. There are the winners. Typically for P=100, W=3.Your task is to determine a selection scheme, using a combination of rank-ordering, numerical scoring, and other methods, by which the final Wpapers will include only papers from among the "best" 2W papers. (By "best",we assume that there is an absolute rank-ordering to which all judges wouldagree.) For example, the top three papers. Among all such methods, the one thatrequired each judge to read the least number of papers is desired.Note the possibility of systematic bias in a numerical scoring scheme. For example, for a specific collection of papers, one judge could average 70points, while another could average 80 points. How would you scale your schemeto accommodate for changes in the contest parameters (P, J, and W)?1997 American MCM ProblemsProblem A The Velociraptor ProblemThe velociraptor,Velociraptor mongoliensis, was a predatory dinosaur that lived during the late Cretaceous period, approximately 75 million years ago. Paleontologists think that it was a very tenacious hunter, and may have hunted in pairs or largerpacks .Unfortunately, there is no way to observe its hunting behavior in the wild as can be done with modern mammalian predators. A group of paleontologists has approached your team and asked for help in modeling the hunting behavior of the velociraptor. They hope to compare your results with field data reported by biologists studying the behaviors of lions, tigers, and similar predatory animals.The average adult velociraptor was 3 meters long with a hip height of 0.5 meters and an approximate mass of 45 kg. It is estimated that the animal could run extremely fast at speed of 60 km/hr for about 15 seconds. After the initial burst of speed ,the animal needed to stop and recover from a buildup of lactic acid in its muscles.Suppose that velociraptor preyed on Thescelosaurus neglectus, a herbivorous biped approximately the same size as the Velociraptor. A biomachanical analysis of a fossilized Thescelosaurus indicates that it could run at a speed of about 50 km/hr. for long period of time.Part1Assuming the velociraptor is a solitary hunter, design a mathematical model that describe a hunting strategy for a single velociraptor stalking and chasing a single Thescelosaurus as well as the evasive strategy of the prey. Assume that the Thescelosaurus can always detect the velociraptor when it comes within 15 meters .but may detect the predator at even greater ranges (up to 50 meters depending upon the habitat and weather conditions. Additionally ,due to its physical structure and strength, the velociraptorhas a limited turning radius when running at full speed. This radius is estimated to be three times the animal's hip height. On the other hand, the Thescelosaurus is extremely agile and has a turning radius of 0.5 meters.Part2Assuming more realistically that the velociraptor hunted in pairs, design a new model that describes a hunting strategy for two velociraptor stalking and chasing a single Thescelosaurus as well as the evasive strategy of the prey. Use the other assumptions and limitations given in Part 1.Problem B Mix Well For Fruitful DiscussionsSmall group meeting for the discussions of important issues, particular long-range planning ,are gaining popularity. It is believed that large groups discourage productive discussion and that a dominant personality will usually control and direct the discussion. Thus ,in corporate board meetings the board will meet in small groups to discuss issues before meeting as a whole, these smaller groups still tun the risk of control by a dominant personality. In an attempt to reduce this danger it is common to schedule several sessions with a different mix of people in each group.A meeting of An Tostal Corporation will be attended by 29 Board Members of which nine are in-house members(i.e., corporate employees).The meeting is to be an all-day affair with three sessions scheduled for the morning and four for the afternoon. Each session will take 45 minutes, beginning on the hour from 9:00 A.M. to 4:00 P.M., with lunch scheduled at noon. Each morning session will consist of six discussion groups with each discussion group led by one of the corporation's six senior officers. None of these officers are board members. Thus each senior officers will not be involved in the afternoon sessions and each of these sessions will consist of only four different discussion groups.The president of the corporation wants a list of board-member assignment to discussion groups for each of the seven sessions. The assignments should achieve as much of a mix of the members as much as possible. The ideal assignment would have each board member in a discussion group the same number of times while minimizing common membership of groups for the different sessions.The assignment should also satisfy the following criteria:1.For the morning sessions ,no board member should be in the same senior officer's discussion group twice.2.No discussion group should contain a disproportionate number of in-house members.Give a list of assignments for members 1-9 and 10-29 and officers 1-6.Indicate how well the criteria in the previous paragraphs are met. Since it is possible that some board members will cancel at the last minute or that some not scheduled will show up, an algorithm that the secretary could use to adjust the assignments with an hour's notice would be appreciated. It would be ideal if the algorithm could also be used to make assignments for future meetings involving different levels of participation for each type of attendee.1998 American MCM ProblemsProblem A MRI ScannersIntroductionIndustrial medical diagnostic machines known as Magnetic Resonance Imager (MRI) scan a three-dimensional object such as a brain, and deliver their results in the form of a three-dimensional array of pixel. Each pixel consists of one number indicating a color or a shade of gray that encodes a measure of water concentration in a small region of the scanned object at the location of the pixel .For instance,0 can picture high water concentration in black (ventricles, blood vessels),128 can picture a medium water concentration in gray(brain nuclei and gray matter),and 255 can picture a low water density in white (liquid-rich white matter consisting of myelinated axons).Such MRI scanners also include facilities to picture on a screen any horizontal or vertical slice through the three-dimensional array (slices are parallel to any of the three Cartesian coordinate axes ).Algorithms for picturing slices through oblique planes ,however ,are proprietary .Current algorithms are limited in terms of the angles and parameter options available ;are implemented only on heavily used dedicated workstations ;lack input capabilities for marking points in the picture before slicing; and tend to blur and "feather out" sharp boundaries between the original pixels.A more faithful, flexible algorithm implemented on a personal computer would be useful.(1)for planning minimally invasive treatments,(2)for calibrating the MRI machines,(3)for investigating structures oriented obliquely in space, such as post-mortem tissue sections in a animal research,(4)for enabling cross-sections at any angle through a brain atlas consisting (4)for enabling cross-sections at any angle through a brain atlas consistingof black-and-white line drawingTo design such an algorithm, one can access the value and locations of the pixels, but not the initial data gathered by the scanners.ProblemDesign and test an algorithm that produces sections of three-dimensional arrays by planes in any orientation in space, preserving the original gray-scale value as closely as possible.Data SetsThe typical data set consists of a three-dimensional array A of numbers A(i,j,k) which indicates the density A(i,j,k) of the object at the location (x,y,z)i,j,k. Typically A(i,j,k) can range from 0 to 255.In most applications the data set is quite large.Teams should design data sets to test and demonstrate their algorithms. The data sets should reflect conditions likely Teams should design data sets to test and demonstrate their algorithms. The data sets should reflect conditions likely to be of diagnostic interest. Teams should also characterize data sets the limit the effectiveness of their algorithms.SummaryThe algorithm must produce a picture of the slice of the three-dimensional array by a plane in space. The plane can have any orientation and any location in space.(The plane can miss some or all data points.)The result of the algorithm should be a model of the density of the scanned object over the selected plane.Problem B Grade InflationBackgroundSome college administrators are concerned about the grading at A Better Class(ABC) college. On average, the faculty at ABC have been giving out high grades(the average grade now given out is an A-),and it is impossible to distinguish between the good and mediocre students .The terms of a very generous scholarship only allow the top 10% of the students to be funded, so a class ranking is required.The dean had the thought of comparing each student to the other students in each class ,and using this information to build up a ranking. For example, if a student obtains an A in a class in which all students obtain an A, then this student is only "average" in this class. On the other hand, if a student obtain the only A in a class, then that student is clearly "above average". Combining information from several classes might allow students to be placed in deciles (top 10%,next 10%,ect.)across the college.ProblemAssuming that the grades given out are(A+,A-,B+,B-,...)can the dean's idea be made to work?Assuming that the grades given out are only (A,B,C,...)can the dean's idea be made to work?Can any other schemes produce a desired ranking?A concern is that the grade in a single class could change many student's deciles. Is this possible?Data SetsTeams should design data sets to test and demonstrate their algorithms. Teams should characterize data sets that limit the effectiveness of their algorithms.Mathematical Contest in Modeling 1999 ProblemsProblem A - Deep ImpactFor some time, the National Aeronautics and Space Administration (NASA) has been considering the consequences of a large asteroid impact on the earth.As part of this effort, your team has been asked to consider the effects of such an impact were the asteroid to land in Antarctica. There are concerns that an impact there could have considerably different consequences than one striking elsewhere on the planet.You are to assume that an asteroid is on the order of 1000 m in diameter, and that it strikes the Antarctic continent directly at the South Pole.Your team has been asked to provide an assessment of the impact of such an asteroid. In particular, NASA would like an estimate of the amount and location of likely human casualties from this impact, an estimate of the damage done to the food production regions in the oceans of the southern hemisphere, and an estimate of possible coastal flooding caused by large-scale melting of the Antarctic polar ice sheet.Problem B - Unlawful AssemblyMany public facilities have signs in rooms used for public gatherings which state that it is "unlawful" for the rooms to be occupied by more than a specified number of people. Presumably, this number is based on the speed with which people in the room could be evacuated from the room's exits in case of an emergency. Similarly, elevators and other facilities often have "maximum capacities" posted.Develop a mathematical model for deciding what number to post on such a sign as being the "lawful capacity". As part of your solution discuss criteria, other than public safety in the case of a fire or other emergency, that might govern the number of people considered "unlawful" to occupy the room (or space). Also, for the model that you construct, consider the differences between a room with movable furniture such as a cafeteria (with tables and chairs), a gymnasium, a public swimming pool, and a lecture hall with a pattern of rows and aisles. You may wish to compare and contrast what might be done for a variety of different environments: elevator, lecture hall, swimming pool, cafeteria, or gymnasium. Gatherings such as rock concerts and soccer tournaments may present special conditions.Apply your model to one or more public facilities at your institution (or neighboring town). Compare your results with the stated capacity, if one is posted. If used, your model is likely to be challenged by parties with interests in increasing the capacity. Write an article for the local newspaper defending your analysis.2000 Mathematical Contest in ModelingProblem A Air traffic ControlDedicated to the memory of Dr. Robert Machol, former chief scientist of the Federal Aviation Agency To improve safety and reduce air traffic controller workload, the Federal Aviation Agency (FAA) is considering adding software to the air traffic control system that would automatically detect potential aircraft flight path conflicts and alert the controller. To that end, an analyst at the FAA has posed the following problems.Requirement A: Given two airplanes flying in space, when should the air traffic controller consider the objects to be too close and to require intervention?Requirement B: An airspace sector is the section of three-dimensional airspace that one air traffic controller controls. Given any airspace sector, how do we measure how complex it is from an air traffic workload perspective? To what extent is complexity determined by the number of aircraft simultaneously passing through that sector (1) at any one instant?(2) during any given interval of time?(3) during a particular time of day? How does the number of potential conflicts arising during those periods affect complexity?Does the presence of additional software tools to automatically predict conflicts and alert the controller reduce or add to this complexity?In addition to the guidelines for your report, write a summary (no more than two pages) that the FAA analyst can present to Jane Garvey, the FAA Administrator, to defend your conclusions.Problem B Radio Channel AssignmentsWe seek to model the assignment of radio channels to a symmetric network of transmitter locations over a large planar area, so as to avoid interference. One basic approach is to partition the region into regular hexagons in a grid (honeycomb-style), as shown in Figure 1, where a transmitter is located at the center of each hexagon.Figure 1An interval of the frequency spectrum is to be allotted for transmitter frequencies. The interval will be divided into regularly spaced channels, which we represent by integers 1, 2, 3, ... . Each transmitter will be assigned one positive integer channel. The same channel can be used at many locations, provided that interference from nearby transmitters is avoided. Our goal is to minimize the width of the interval in the frequency spectrum that is needed to assign channels subject to some constraints. This is achieved with the concept of a span. The span is the minimum, over all assignments satisfying the constraints, of the largest channel used at any location. It is not required that every channel smallerthan the span be used in an assignment that attains the span.Let s be the length of a side of one of the hexagons. We concentrate on the case that there are two levels of interference.Requirement A: There are several constraints on frequency assignments. First, no two transmitters within distance of each other can be given the same channel. Second, due to spectral spreading, transmitters within distance 2s of each other must not be given the same or adjacent channels: Their channels must differ by at least 2. Under these constraints, what can we say about the span in,Requirement B: Repeat Requirement A, assuming the grid in the example spreads arbitrarily far in all directions.Requirement C: Repeat Requirements A and B, except assume now more generally that channels for transmitters within distance differ by at least some given integer k, while those at distance at most must still differ by at least one. What can we say about the span and about efficient strategies for designing assignments, as a function of k?Requirement D: Consider generalizations of the problem, such as several levels of interference or irregular transmitter placements. What other factors may be important to consider?Requirement E: Write an article (no more than 2 pages) for the local newspaper explaining your findings.2001 Mathematical Contest in Modeling (MCM)Problem A: Choosing a Bicycle WheelCyclists have different types of wheels they can use on their bicycles. The two basic typesof wheels are those constructed using wire spokes and those constructed of a solid disk (see Figure 1) The spoked wheels are lighter, but the solid wheels are more aerodynamic.A solid wheel is never used on the front for a road race but can be used on the rear of the bike.Professional cyclists look at a racecourse and make an educated guess as to what kind of wheels should be used. The decision is based on the number and steepness of the hills, the weather, wind speed, the competition,and other considerations. The director sportif of your favorite team would like to have a better system in place and has asked your team for information to help determine what kind of wheel should be used fora given course.Figure 1: A solid wheel is shown on the left and a spoked wheel is shown on the right. The director sportif needs specific information to help make a decision and has asked your team to accomplish the tasks listed below. For each of the tasks assume that the same spoked wheel will always be used on the front butthere is a choice of wheels for the rear.Task 1. Provide a table iving the wind peed at which the power required for a solid rear wheel is less than for a spoked rear wheel. The table should include the wind speeds for different road grades starting from zero percent to ten percent in one percent increments. (Road grade is defined to be the ratio of the total rise of a hill divided by the length of the road. If the hill is viewed as a triangle, the grade is the sine of the angle at the bottom of the hill.) A rider starts at the bottom of the hill at a speed of 45 kph, and the deceleration of the rider is proportional to the road grade.A rider will lose about 8 kph for a five percent grade over 100 meters.Task 2. Provide an example of how the table could be used for a specific time trial courseTask 3. Determine if the table is an adequate means for deciding on the wheel configuration and offer other suggestions as to how to make this decision.Problem B: Escaping a Hurricane's Wrath (An Ill Wind...)Evacuating the coast of South Carolina ahead of the predicted landfallof Hurricane Floydin 1999 led to a monumental traffic jam. Traffic slowed to a standstill on Interstate I-26, which is the principal route going inland from Charleston to the relatively safe haven of Columbia in the center of the state. What is normally an easy two-hour drive took up to 18 hours to complete. Many cars simply ran out of gas along the way.Fortunately, Floyd turned north and spared the state this time, but the public outcry is forcing state officials to find ways to avoid a repeat of this traffic nightmare.The principal proposal put forth to deal with this problem is the reversalof traffic onI-26, so that both sides, including the coastal-bound lanes,have traffic headed inland from Charleston to Columbia. Plans to carry this out have been prepared (and posted on the Web)by the South Carolina Emergency Preparedness Division. Traffic reversal on principal roads leading inland from Myrtle Beach and Hilton Head is also planned.A simplified map of South Carolina is shown. Charleston has approximately 500,000 people, Myrtle Beach has about 200,000 people, and another 250,000 people are spread out along the rest of the coastal strip. (More accurate data,if sought, are widely available.)The interstates have two lanes of traffic in each direction except in the metropolitan areas where they have three. Columbia, another metro area of around 500,000 people, does not have sufficient hotel space to accommodate the evacuees (including some coming from farther northby other routes), so some traffic continues outbound on I-26 towards Spartanburg; on I-77 north to Charlotte; and on I-20 east to Atlanta. In 1999, traffic leaving Columbia going northwest was moving only very slowly. Construct a model for the problem to investigate what strategies may reduce the congestion observed in 1999. Here are the questions that need to be addressed:1.Under what conditions does the plan for turning the two coastal-bound lanes of I-26 into two lanes of Columbia-bound traffic, essentially turning the entire I-26 into one-way traffic, significantly improve evacuation traffic flow?2.In 1999, the simultaneous evacuation of the state's entire coastal region was ordered. Would the evacuation traffic flow improve under an alternative strategy that staggers the evacuation, perhaps county-by-county over some time period consistent with the pattern of how hurricanes affect the coast?3.Several smaller highways besides I-26 extend inland from the coast. Under what conditions would it improve evacuation flow to turn around traffic on these?4.What effect would it have on evacuation flow to establish more temporary shelters in Columbia, to reduce the traffic leaving Columbia?5.In 1999, many families leaving the coast brought along their boats, campers, and motor homes. Many drove all of their cars. Under what conditions should there be restrictionson vehicle types or numbers of vehicles brought in order to guarantee timely evacuation? 6.It has been suggested that in 1999 some of the coastal residents of Georgia and Florida, who were fleeing the earlier predicted landfalls of Hurricane Floyd to the south, came upI-95 and compounded the traffic problems. How big an impact can they have on the evacuation traffic flow? Clearly identify what measures of performance are used to compare strategies. Required: Prepare a short newspaper article, not to exceed two pages,explaining the results and conclusions of your study to the public.问题 A: 选择自行车车轮骑自行车的人有几种不同类型的车轮可以用在他们的自行车上。

共价有机框架(COFs)材料最新应用研究进展王帅【摘要】共价有机框架材料是一类由共价键构筑,具有周期性结构和结晶性的有机多孔聚合物.由于共价有机框架材料由轻质子元素链接,密度比较小,热稳定性比较高,而且因为其多孔性,在气体吸附、能量存储、非均相催化等领域得到了广泛应用.本文综述了近年来COFs材料在环境污染物治理领域的最新研究进展.【期刊名称】《江西化工》【年(卷),期】2018(000)002【总页数】3页(P1-3)【关键词】共价有机框架;共价键;多孔材料;环境修复【作者】王帅【作者单位】东华理工大学核科学与技术工程学院,江西南昌330013【正文语种】中文1 前言2005年，Yaghi等[1]首次制备了共价有机框架材料(COF-1和COF-5)，它是一类新型的二维片层材料，通过硼酯的共价键构筑。

由于该材料有轻元素(H、C、N、O、B等)通过共价键构筑，具有很多独特的性质，如较低的密度，高的热稳定性，较大的比表面积等，这使得该材料在气体吸附[2]、催化[3]、能量存储及光电转化[4]等领域得到广泛应用。

由于COFs材料结构和功能的可调控性，其在环境中污染物的治理方面展现出巨大的潜力。

本文将综述近期COFs材料在环境污染物治理方面的最新进展。

图1 COF-1和COF-5的合成及其结构示意图2 COFs在环境污染物治理方面的应用2.1 汞离子吸附汞污染造成的环境污染和引起的公众健康威胁，是人类面临的重大挑战。

发展有效的分离方法势在必行[5]。

2016年，Ding等[6]设计合成了报道了基于腙的共价有机框架COF-LZU8的合成，硫醚均匀分布于孔道中。

该材料可以有效的去除重金属离子汞，而且吸附汞后发生了明显的荧光淬灭，因此该材料也为汞离子的检测提供有效的方法。

固体核磁和X射线光电子能谱测试分析得知硫醚在汞的去除中起到了至关重要的作用。

该工作是COFs材料在重金属离子去除方面的首次应用，为其在环境领域的应用提供了基础。

2004年9月第5期浙　江　教　育　学　院　学　报JOURNA L OF ZHE J I ANG E DUC ATI ON I NSTIT UTE September 2004N o 15 收稿日期:2004-07-08 作者简介:张一平(1972-),女,浙江余杭人,浙江教育学院理工学院副教授,理学博士.均相催化剂的固载化研究张一平(浙江教育学院理工学院,浙江杭州310012) 摘　要:　介绍了均相催化剂的固载化研究进展.可以通过离子交换、密封和接枝等方法将均相催化剂固载于载体之上,而载体和接枝过渡物质的接枝长度也会影响固载化催化剂的活性.关键词:固载;均相催化剂;多相催化剂;载体中图分类号:O631　文献标识码:A 文章编号:1671-6574(2004)05-0013-061　前　言多相催化与均相催化是催化领域里的两大类型.多相催化剂的优点是催化剂的活性组分可以广泛变化;使用的温度范围十分广;容易从产品中分离出催化剂,因而容易实现工业化.但是也有其缺点,主要是对表面活性中心的认识不够完整,因而催化剂的设计或改进比较困难;由于表面的不均一性,表面活性组分的利用率十分低;反应的方向不容易控制,活性与选择性均不太高等.与之相对应,由于均相催化剂中的配位基可以适当选择,使金属原子周围有特定的电子与空间性质,这样使它仅能促进某一反应而具有高度的选择性.而且在均相催化剂中所有的金属原子都能发挥催化活性.而在多相催化剂中大多数金属原子是在体相,在表面也仅有部分金属原子发挥催化活性,这样就决定了均相催化剂具有比多相催化剂高得多的金属原子利用率.同时,由于均相催化剂比多相催化剂在更为温和的条件下(低温低压)进行反应,因而降低了能量损耗.均相催化剂尽管有这些优点,但要广泛使用时也有不少问题,除了一般碰到的腐蚀性问题之外,主要是均相催化剂难以从液相反应产物中分离出来.特别在以贵金属的络合物作催化剂时,更要注意分离问题,否则既不经济又要污染产品,影响下一步反应.为了使均相催化剂能更广泛地使用,许多学者进行了大量的研究,普遍采用均相催化剂的固载化方法来解决这个问题.2　均相催化剂固载化的概念所谓均相催化剂的固载化,就是把均相催化剂以物理或化学方法使之与固体载体相结合,而形成一种特殊的催化剂.在这种固载催化剂中的活性组分往往与均相催化剂具有同样的性质和结构,因而保存了均相催化剂的优点,例如高活性和高选择性等.同时又因结合在固体上,具有了多相催化剂的优点,例如容易从产品中分离与回收催化剂等.而且,对这类催化剂进行研究,有可能在分子水平上研制出反应性能优异的催化剂,并对其催化作用机理有进一步的认识.由于均相催化剂被固定在固体上,其浓度不受溶解度限制,可以提高催化剂的浓度,就能使用较小的反应容器,这样可以进一步降低生产费用.因而研究均相催化剂的固载,在理论上和实践上均具有重大意义.固载化催化剂所采用的载体一般为有机高分子化合物和无机氧化物.无机氧化物,如SiO 2、Al 2O 3、MC M -41、MC M -48等,在机械强度、热和化学稳定性及来源上均明显优于高分子载体.因而在无机载体上固载化,是一个很有实用意义的重要方向.3　均相催化剂的固载化方法311　离子交换金属离子可以通过离子交换(I on exchange )固载于分子筛和酸性粘土上,如图1所示.例如钼和钨可交换到类水滑石阴离子粘土上[1,2].但主要的缺点是金属配合物容易流失到溶液中.312　密封将金属配合物密封于固体基质中(Encapsulation ),这也是均相催化剂固载化的方法之一.例如,瓶中造船方法(Ship-in-a-bottle )(从较小部分原位组装金属配合物),配合物形成后被截留在分子筛笼中,如图2所示.常用于固载酞菁、联吡啶和Schiff 碱类配体[3～5].但未配合的金属、不含金属的配合物和目标配合物的碎片可能阻塞反应物和Π或产物的扩散通道.图1　均相催化剂固载化方法一:离子交换 图2　均相催化剂固载化方法二:密封313　接枝还可以接枝配合物到固体表面,通过形成共价键实现金属配合物在固体表面的引入,如图3所示.接枝的方法可以是直接引入金属配合物(G rafted ),例如浸渍[6],或溶胶-凝胶法.也可以是通过接枝过渡物质(S pacer ligand )使载体表面功能化后引入金属配合物(T ethered )[7～9].图3　均相催化剂固载化方法三:接枝无机载体表面的活性基团一般为羟基,常采用含有三甲氧基或三乙氧基等活性基团的有机硅化合物作为接枝过渡物质,利用烷氧基与羟基易发生缩合反应而放出醇的性质,实现配合物的引入(见图4).这种载体表面功能化后接枝金属配合物得到的催化剂具有结构性能稳定的优点,可用于催化Diels-Alder 双烯合成、羰基化、Friedel-Crafts 反应、Heck 反应、酯化、烯丙基41浙江教育学院学报 2004年胺化、加氢、氧化和各种缩合反应.图4　利用有机硅化合物进行的接枝过程还有报道以杂多酸例如磷钨酸(PT A )作为接枝过渡物质,将Rh 均相配合物连接在Al 2O 3载体上[10].4　影响固载催化剂活性的几个因素一般来说,固载化后的催化剂常与相应的均相催化剂具有相近的活性,相同的反应机理.但也有活性变高和变低的情况.影响固载催化剂活性的因素主要有:411　载体的影响均相催化剂固载化后,增加了一个载体因素,当然要考虑载体对催化剂活性的影响.固载化催化剂的载体既要有一定的表面积,对孔径分布也有一定要求.C orma 等人[11,12]将图5所示的天然脯氨酸衍生的含氮配体固载于硅胶(孔径63-200μm )和修饰的USY 分子筛(Ultrastable Y zeolite ,孔径12-30!)上,然后再作为Rh 催化剂的载体,用于乙酰氨基肉桂酸乙酯(a )或苯甲酰氨基肉桂酸乙酯(b )的不对称加氢,反应结果见表1.图5　固载化的脯氨酸衍生的含氮配体催化剂表1　乙(或苯甲)酰氨基肉桂酸乙酯的不对称加氢底物对映体选择性(%ee 3)均相硅胶USY 分子筛a841188109719b 901393159618 3:对映体过量值51第5期　张一平:均相催化剂的固载化研究 从表1可以看出,USY 分子筛固载的配合物上的对映体选择性要高于硅胶固载或均相催化剂,而且分子筛固载的催化剂多次重复使用后无活性降低或Rh 组分的流失.这是由于载体孔径的几何约束而导致配合物构象柔韧性受限制,从而防止配合物聚集,对催化剂的性能产生正影响.在以孔径较小的USY 分子筛为载体时,以体积小的a 为底物时所获得的对映体选择性要高于b 为底物时.这是因为载体孔径小时,分子比较大的底物不易进入固体催化剂的孔内,不能接触固定在孔内的催化剂活性组分,所以活性降低.Thomas 等人[13,14]发现载体也影响产物的构型.他们以中孔分子筛MC M -41(孔径25-100!)为载体,将二茂铁基双膦配体1与氨丙基硅烷2作用后,再与PdCl 2反应,制得硅烷化的Pd 配合物4,固载于MC M -41上,将此固载催化剂5用于生成哌啶甲酸乙酯7的反应(见图6),可以得到对映体选择性17%ee ,转化数291的反应结果,并且没有催化剂活性组分的流失.而用均相催化剂4反应时,产物为外消旋体,转化数98.尽管固载催化剂得到的对映体选择性还不是很理想,但这为避免外消旋产物的拆分带来了希望.图6　载体对产物构型的影响412　接枝过渡物质接枝长度的影响在一篇较早的文献中(1985年),K inting 等人[15]报道了SiO 2上固载手性Rh 催化剂中Si 与P 之间接枝长度的影响(见图7).首先,甲硅烷基化的手性单膦1a-c 被锚定在硅胶(K iesegel 100)上,然后将得到的膦化的载体与[RhCl (C 2H 4)2]2反应,这就是固载催化剂2a-c.而将这些固载的Rh 配合物2a-c 用于α-乙酰氨基肉桂酸(3)不对称加氢生成(R )-乙酰苯丙氨酸(4),所显示的稳定性和产物选择性均优于相应的均相催化剂Rh -1,这可归因于所谓的“活性位分离”(site-is olation ).由于固载化使活性位彼此分开,防止了相互作用而失活[16].61浙江教育学院学报 2004年图7　接枝长度对固载催化剂性能的影响接枝长度影响了催化剂的选择性和催化剂流失.当接枝长度增加时,对映体选择性增加,ee 值(对映体过量值)从2a (n =1)为催化剂时的67%增加到2c (n =5)的87%;而催化剂流失减少,催化剂三次重复使用后,对于2a (n =1),Rh 的流失量为90%,2c (n =5)为催化剂时,这个值仅为38%.这是因为接枝过渡物质较长,则越柔韧,Rh 配合物容易在表面形成二齿配位形式.此外,均相催化剂的固载浓度,金属原子的电子性质,反应介质(或溶剂)等等都对活性产生影响.随着研究工作的深入与发展,相信一定能弄清所有影响固载催化剂活性的因素.参考文献:[1]Vaccari A.Preparation and catalytic properties of cationic and anionic clays [J ].Catal.T oday.,1998,41:53-71.[2]Vaccari A.Clays and catalysis :a promising future [J ].Appl.Clay Sci.,1999,14:161-198[3]Bedioui F.Z eolite-encapsulated and clay -intercalated metal porphyrin ,phthalocyanine and Schiff-base com plexes as m odels for biomimetic oxidation catalysts :an overview [J ].C oord.Chem.Rev.,1995,144:39-68.[4]Balkus Jr KJ.,K hanmamedova A K.,Dix on K M.,Bedioui F.Oxidations catalyzed by zeolite ship-in-a-bottle com 2plexes [J ].Appl.Catal.A.,1996,143:159-173.[5]Parton R F.,Vankelecom I F J.,T as D.,Janssen KB M.,K nops -G errits PP.,Jacobs P A.Membrane occluded cat 2alysts :a higher order mimic with im proved per formance [J ].J.M ol.Catal.A :Chemical.,1996,113:283-292.[6]Brunel D.Functionalized micelle-tem plated silicas (MTS )and their use as catalysts for fine chemicals [J ].M icroporous Mes oporous Mater.,1999,27:329-344.[7]S ong Ch E.,Lee S G.Supported chiral catalysts on inorganic materials [J ].Chem.Rev.,2002,102:3495-3524.[8]David J C -H.H om ogeneous catalysis -new approaches to catalyst separation ,recovery ,and recycling [J ].Science.,2003,299:1702-1706.[9]Balcar H.,Cejka J.,Sv oboda J.[Rh (cod )Cl ]2com plex imm obilized on mes oporous m olecular sieves MC M -41-a new hybrid catalyst for polymerization of phenylacetylene [J ].J.M ol.Catal.A :Chemical.,2003,203:287-298.71第5期　张一平:均相催化剂的固载化研究 81浙江教育学院学报 2004年[10]Augustine R.,T anielyan S.,Anders on S.,Y ang H.A new technique for anchoring hom ogeneous catalysts[J].Chem.C ommun.,1999:1257-1258.[11]C orma A.,Iglesias M.,del Pino C.,Sa′nchez F.J.New rhodium com plexes anchored on m odified USYzeolites.Aremarkable effect of the support on the enantioselectivity of catalytic hydrogenation of prochiral alkenes[J].Chem.S oc.,Chem.C ommun.,1991:1253-1254.[12]C orma A.,Iglesias M.,M ohino F.,Sa′nchez F.Heterogenised catalysts on zeolites.Synthesis of new chiral Rh(I)com plexes with(2S,4R)-trans-4-RC OO-2-(t-butylaminocarbonyl)pyrrolidines and(2S,4S)-cis-4-RC ONH-2-(t-butyl2 aminocarbonyl)pyrrolidines.Heterogenisation on silica and a USY-zeolite and study of the role of support on their cata2 lytic profile in hydrogenation of olefins[J]anomet.Chem.,1997,544:147-156.[13]Raynor S A.,Thomas J M.,Raja R.,Johns on B F G.,Bell R G.,Mantle M D.A one-step,enantioselective re2duction of ethyl nicotinate to ethyl nipecotinate using a constrained,chiral,heterogeneous catalyst[J].Chem.C om2 mun.,2000:1925-1926.[14]Thomas J M.,Maschmeyer T.,Johns on B F G.,Shephard D S.C onstrained chiral catalysts[J].J.M ol.Catal.A:Chemical.,1999,141:139-144.[15]K inting A.,K rause H.,Capka M.S ilica-supported chiral rhodium com plexes for asymmetric hydrogenation[J].J.M ol.Catal.,1985,33(2):215-223.[16]Pugin B.Imm obilized catalysts for enantioselective hydrogenation:The effect of site-is olation[J].J.M ol.Catal.A:Chemical.,1996,107:273-279.The Immobilization of H omogeneous CatalystZHANG Y i-ping(Science School,Zhejiang Education Institute,Hangzhou310012,China) Abstract:The progress on the research of imm obilization of hom ogeneous catalyst is intro2 duced.The approaches of ion exchange,encapsulation and tethered can be used to imm obilize the hom ogeneous catalyst,the carrier and the length of the tether effect on the catalytic activity of imm obilized catalyst.K ey w ords:imm obilization;hom ogeneous catalyst;heterogeneous catalyst;carrier。

介孔二氧化硅微球的制备方欣闪【摘要】以正硅酸乙酯为硅源,氨水为催化剂,通过改变表面活性剂,我们可以在碱性条件下合成不同介孔形貌的二氧化硅微球.这些粒子可以通过透射电子显微镜得到表征.在采用带电荷模板十六烷基三甲基溴化铵的水溶液的条件下将生成具有高度有序介孔通道的不规则球形粒子.在以酒精/水为共溶剂条件下将生成表面更光滑的介孔微球.在均相不带电模板十二烷基胺的条件下可以得到无序介孔通道的球形粒子.【期刊名称】《长春理工大学学报（自然科学版）》【年(卷),期】2010(033)002【总页数】4页(P90-93)【关键词】介孔形貌;二氧化硅微球;正硅酸乙酯【作者】方欣闪【作者单位】暨南大学理工学院材料科学与工程系,广州,510632【正文语种】中文【中图分类】TQ311自从1992年Kresge等在阳离子表面活性剂溶液中进行自组装合成了多孔的二氧化硅材料以来[1，2]，利用有机表面活性剂作为模板制备这种带有可控的孔径三维有序无机材料的工作已经得到了很大程度的发展。

这种材料通常被制成粉末，但近来也有合成带有开放介孔纳米尺度的胶体微粒的工作报道[3-5]。

例如，在管状反应器中通过升高温度，利用气溶胶沉积技术，获得了平均粒径是200nm的带有介孔的微粒。

利用简单的淬火技术，更小尺寸的 MCM-41[1，2]氧化硅类的有序介孔分子筛材料也被合成出来。

在这一过程中，悬浮体系的稀释和pH值的中和对于降低共沉积的速度，最后获得稳定的介孔纳米微粒的悬浮体系起到了重要的作用，并且在540℃热处理二氧化硅的框架结构除去有机模板不会损坏介孔结构的完整。

这种据称按液晶模板(1iquid crystal template，LCT)机理形成的分子筛材料，具有比表面积大、孔道大小均匀、六方有序、孔径在1.5～10 am范围内连续可调以及较好的热稳定性和水热稳定性等特点，在介孔分子筛，催化领域，色层分析，表面磨光，纳米载药和药物缓释等方面都有着广泛的应用[6，7]。