铝交联皂石的合成和表征及催化性能

用XRD、化学分析、IR、MASNMR、TPD等手段表征了合成皂石及其铝交联物的结构。结果表明:皂石的交联密度与四面体层电荷和交联条件(Al/土比)有关。在乙醇氨化反应中,交联皂石显示了较好的催化活性和选择性。皂石的交联密度与液相产物分布的关系表明层柱材料对此反应具有择形催化作用。醇氨化反应可能是在吸附态NH_3和气相醇分子间进行的。     

具有超大通道结构的介孔氧化硅柱层状钛酸的合成和催化应用初探

A mesoporous (d=2.3mm) silica-pillared layered tetratitanate with a super gallery (d₀₀₁=1.84mm)was prepared by first preswelling layered tetratitanate with n-dodecyl amine, then reacting with 20wt% NH₂(CH₂)₃Si(OC₂H₅)₃ aqueous solution, and finally calcinating the resultant solid product in air at 550℃. All the reaction was carried out hydrothermally in an autoclave at 130℃. The obtained material has a relatively high BET surface area of 204m²·g^-1 and a thermal stability beyond 600℃. The catalytic application of the material was also investigated by using the dehydration of isopropanol and the reform of n-hexane as two probing reactions.     

以四甲基铵硅酸盐为柱化剂合成层柱状MCM-36分子筛

以层状MCM-22P为前驱体,四甲基铵硅酸盐为柱化剂,采用动态水热法考察了MCM-36分子筛的合成条件,并通过XRD、N2物理吸附、TEM、27Al-MAS NMR以及NH3-TPD等手段对合成分子筛进行了表征。结果表明,与传统的采用正硅酸乙酯为柱化剂的柱化过程相比,以四甲基铵硅酸盐为柱化剂时,已溶胀的前驱体不经干燥处理即可直接在含水体系进行柱化插层合成得到层间距均一的层柱状MCM-36分子筛,适宜的合成条件为:先在80℃的高pH值(约13.5)环境下对前驱体溶胀24 h,然后在100℃下柱化插层24 h。表征结果表明,MCM-36分子筛具有层内微孔和层间介孔的复合孔道结构以及较大的比表面积(特别是外比表面积);与HMCM-22相比,HMCM-36的表面酸性虽明显降低,但其层间介孔结构的形成使大量B酸中心暴露于大分子易于接近的层间介孔孔壁,可为涉及较大分子的催化反应提供更多可接近的活性位中心。     

介孔铁铝/蒙脱土复合材料：解离柱撑制备、结构及催化羟基化性能

利用极稀悬浮液中蒙脱土的解离作用并结合柱化技术过程，制备了介孔结构的铝铁/蒙脱土复合材料(Fe-Al/mmt)；并采用粉末X射线衍射、氮等温吸脱附、傅立叶红外光谱、紫外可见光漫反射光谱及苯酚催化羟基化反应表征了其结构和性能。结果显示，铁铝聚合前驱液中铁/铝比影响复合材料中蒙脱土的解离程度，且仅当低铁/铝比时(即Fe/(Fe+Al)物质的量的比介于0.05～0.3)，嵌入解离的蒙脱土片层间的混合铁铝物种呈现能耐温350 ℃的热稳定性；氮等温吸脱附分析反映出这种解离的蒙脱土堆积结构呈现介孔特征，孔径分布窄，介于2.0～2.3 nm；红外分析表明材料表面具有L酸和B酸位，并且L酸位量与嵌入解离的蒙脱土结构中的混合铁铝物种相关；由于结构中混合铁铝物种的存在及相应的Si-O → Fe、Al-O → Fe间的电子跃迁，Fe-Al/mmt材料在紫外区呈现宽泛的能量吸收特征。这些结果说明，由于混合铁铝物种嵌入于解离的蒙脱土片层堆积结构中，形成了“卡片屋”式介孔结构。实验条件下，Fe/(Fe+Al)物质的量的比为0.3的Fe-Al/mmt呈现较佳的催化羟基化性能，苯酚转化率为36.7%，二酚产物选择性32.3%；并且初步表明铝掺杂后，通过铁铝比和表面酸性的调整，材料的部分选择氧化性能可以得到改善。     

Cationic versus Anionic Pillared Layered Substrates: Comparison of the Pillaring Reactions and the Resulting Porosities

Cationic clays and Layered Double Hydroxides (LDHs) are both layeredion exchangers, in which a stable (micro)porosity can be induced via apillaring process. For the cationic clays, the [Zr]-pillaring of hectoritecreates a broad micropore distribution with the maximum at 1.42–2.12nm. The [Al]-equivalent exhibits a narrower distribution, with pores between0.71 and 1.06 nm being dominant. In case of the [Zr]-pillared form a surfacearea of 294 m²/g and a micropore volume of 0.118cm³/g have been obtained. The same reaction on the syntheticlaponite clay reveals a much higher surface area (606 m²/g)and porosity (µPV = 0.336 cm³/g). Forlaponite, extra pores are created in the supermicropore-small mesoporeregion due to the preferential edge-to-face and edge-to-edge stacking of itssmaller sized clay layers.For the pillaring of MgAl- and ZnAl-LDHs with polyoxometalates (POMs),using large organic anions for pre-swelling purposes forms the mostpromising method for the creation of stable pores. It avoids the formationof sidephases, and gives rise to medium(-high) µPVs. Charge density onthe layers forms the key factor, lowering it improves the porositycharacteristics significantly. [Fe(CN)₆]-MgAl-LDHs exhibitmore spectacular properties, with surface areas and µPVs exceedingthose of pillared hectorite. A variation in the charge density via theM ^II/M ^III ratio optimizes theporosity properties. A M ^II/M ^IIIratio of 3.33 results in a SA of 499 m²/g and a µPV of0.177 cc/g. For LDHs, both types of pillars create mainly small micropores,with a diameter smaller than 0.71 nm.     

高比表面TiO_2柱层状HLaNb_2O_7的制备和表征

采用分步离子交换法，将含钛多聚阳离子嵌入层状镧铌酸（HLaNb_2O_7）的层 间，通过焙烧，制得了TiO_2柱层状镧铌酸（TiO_2-HLaNb_2O_7）。应用XRD， FTIR，TEM和BET（Brunauer-Emmett-Teller）等技术对该材料进行了表征。结果表 明，TiO_2-HLaNb_2O_7具有较大的层间距（1.61 nm，450 ℃）和较高的比表面积 （S_(BET) = 132 m~2·g~(-1)），而且是一中孔材料，其孔径分布曲线上呈现一 狭窄的孔分布，最可几孔直径为3.3 nm。     

Intercalative reaction of a cobalt(III) cage complex,Co(sep)3+, with magadiite,a layered sodium silicate

The cationic metal cage complex (1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]cicosane)cobalt(III), Co(sep)³⁺ has been investigated as a potential pillaring reagent for Na⁺-magadiite (Na_1.7Si₁₄O_27.9(OH)_1.9 · 7.6 H₂O) a synthetic layered sodium silicate. Reaction of Na⁺-magadiite with aqueous solutions of Co(sep)Cl₃ at 25°C resulted in the binding of Co(sep)³⁺ cations to the external crystalline surface of the layered silicate. In contrast, an intercalated product exhibiting a 17.6 Å basal spacing was generated by reaction at 100°C.²⁹Si MAS NMR and FT-IR spectroscopy indicate that Co(sep)³⁺ intercalated reaction products retain the magadiite layer structure. Moreover, scanning electron micrographs of the reaction products showed retention of the original particle morphology, suggesting a topotactic intercalation. However, during intercalation, some of the Co(sep)³⁺ was found to undergo an unusual demetalation reaction leaving a combination of Co(II) and Co(sep)³⁺ between the layers. Nitrogen surface area analysis showed that only a small amount of microporous surface existed in the Co(sep)³⁺ intercalated derivative, suggesting that most of the interlayer space is stuffed with cobalt species.     

氧化铬柱层状铌酸的合成和表征

本文报道先用正丙胺预支撑层状铌酸,然后同氯化四甲铵水溶液进行离子交换,最后再与醋酸铬(Ⅲ)水溶液反应可得含铬(Ⅲ)聚合离子支撑的层状铌酸。进一步焙烧所得含铬(Ⅲ)聚合离子支撑的层状铌酸可得氧化铬柱层状铌酸。该材料具有较高的热稳定性(>700℃)和BET比表面(66.7 m²/g),是一类中等偏弱的新型多孔固体酸(平均孔径为3.3 nm,总酸量为188.3 μmol/g,且主要为Lewis酸)。     

层状光催化材料H2La2Ti3O10/CdS的制备及其性质研究

通过改善酸交换过程,用分步柱撑法制备了一种新的层柱材料H2La2Ti3O10/CdS.用X射线粉末衍射（XRD）、红外光谱（IR）、比表面（BET）等方法对材料进行了表征;以光催化降解苯胺为探针对材料的活性进行了研究.结果表明： 通过柱撑CdS,H2La2Ti3O10的光催化性能得到明显提高;同时,对试验条件进行了优化,得到了最佳催化反应条件.     

混合金属络合物羟基铬铝交联蒙托土的合成

用取代法和共聚法合成了不向Cr/Al比的混合金属络合物羟基铬铝交联蒙托土,用XRD、DTA考察了其热稳定性,用~(27)Al-NMR、UV、ESR等技术对柱化溶液中铬和铝的状态进行了研究。结果表明,两种方法均合成出结构相近且底面间距d(001)为1.90～2.49nm的羟基铬铝交联蒙托土。发现Cr/Al比对羟基铬铝聚合物的结构、d(001)值、比表面热稳定性均有较大影响;随Cr/Al比的增加,d(001)逐渐增加,热稳定性下降,但在惰性气氛下热稳定性较好(>500℃)。