层状(脯氨酸-N-甲基膦酸-磷酸氢)锆的合成及插层性能研究

以高结晶度制备了层状(脯氨酸-N-甲基膦酸-磷酸氢)锆(α-ZPMPP)晶体(层间距为1.52nm),并研究了其常温下对正丁胺的插层性能,用元素分析、IR、XRD和TG-DSC热分析对α-ZPMPP及其插层复合物进行了表征.结果表明,层状α-ZPMPP具有形成超分子主-客体化合物的插层性能,正丁胺客体分子在主体底物中形成单分子层,并插入α-ZPMPP中,使层间距增大0.45nm,插入的正丁胺可在150～250℃被脱除.     

正丁胺对苯膦酸铜的插层反应研究

分别采用溶液搅拌和超声的方法,研究了有机正丁胺分子对苯膦酸铜的插层反应.对插层复合物进行了红外光谱(IR)、X射线粉末衍射(XRD)和热重分析等测试及结构分析.结果表明,有机正丁胺的插入使得苯膦酸铜的层间距增大.     

α-磷酸氢锆-六氢吡啶的超分子插层组装及其对废水中酚的吸收研究

采用直接插入法制备了六氢吡啶(HHP)对α-Zr(HPO4)2·H2O(α-ZrP)的超分子插层复合物α-ZrP-HHP。用元素分析、红外光谱(IR)、X射线粉末衍射(XRD)和TG-DSC热分析等手段表征其结构,结果表明,六氢吡啶的插入使层间距增大了0·59nm,插入的六氢吡啶客体分子在主体底物中形成双分子层。研究了α-ZrP-HHP对含酚类物质(包括苯酚、4-氯苯酚、2,4-二氯苯酚)废水的吸附,结果表明,α-ZrP-HHP对上述三种酚类物质的吸附量呈如下规律:2,4-二氯苯酚>4-氯苯酚>苯酚。     

三聚磷酸二氢铝与有机胺的插层反应特征

采用IR、XRD、SEM、EDS、DT-TG和滴定实验等技术手段研究主体三聚磷酸二氢铝(ATP)与客体甲胺、乙胺、正丙胺和正丁胺等有机胺的插层反应特性。 实验结果表明,ATP与甲胺、乙胺、正丙胺、正丁胺发生了化学反应,有机胺中的N与ATP层间-OH上的H形成配位键。 这些有机胺通过插层反应改变了ATP的酸性、层间距和热分解温度,但没有改变颗粒的层状形貌。 层间距从0.795 nm增大至1.71 nm,层间距d与有机胺的碳原子数Cn呈线性关系：d=0.229Cn+0.811,R2=0.9986。 有机胺分子链越长则越具有剥离倾向。     

偏氯乙烯共聚物/层状双金属氢氧化物纳米复合材料的制备与表征

通过硝酸根插层层状双金属氢氧化物(LDH)与可逆加成-断裂链转移(RAFT)试剂S,S’-对(α,α’-二甲基-α″-乙酸)三硫代碳酸酯(CTA)阴离子的离子交换制备CTA阴离子插层LDH,再通过原位RAFT活性自由基聚合制备偏氯乙烯-丙烯酸甲酯(VDC-MA)共聚物/LDH纳米复合材料.采用傅里叶变换红外光谱、元素分析和X-射线衍射、透射电子显微镜、凝胶渗透色谱仪和热失重仪表征了CTA阴离子插层LDH和纳米复合材料的结构和性能.结果表明,CTA阴离子可以置换硝酸根阴离子插入到LDH层间,LDH层间距由0.89 nm增大到1.50 nm;在原位RAFT聚合过程中,LDH逐渐剥离,LDH以纳米层板形式分散在VDC-MA共聚物基体中;VDC-MA共聚物数均分子量随加入的插层CTA阴离子含量增加而减小,聚合具有活性特征.此外,含量LDH的引入可明显提高VDC-MA共聚物的热稳定性.     

水溶性阳离子型卟啉对层状磷酸锆插层行为的研究

比较了水溶性卟啉meso-四(4-N-甲基吡啶基)卟啉(TMPyP)对具有不同层间距和结构的层状磷酸锆[α-磷酸锆(α-ZrP)和γ-磷酸锆(γ-ZrP)]的插层行为. 研究发现: 相比α-磷酸锆, γ-磷酸锆虽然具有相对较大的层间距, 但同α-磷酸锆一样, TMPyP不能直接嵌入其中. 为嵌入TMPyP, 用预撑剂正丁胺(BA)处理磷酸锆. TMPyP可以嵌入α-ZrP•BA和α-ZrP•2BA(分别为单层丁胺和双层丁胺嵌入α-磷酸锆而形成的插层化合物), 其中, TMPyP以较短的时间与单层排列的丁胺交换而嵌入磷酸锆; 而卟啉却不能嵌入具有较大层间距的γ-ZrP•2BA(双层丁胺嵌入γ-磷酸锆而形成的一种很稳定的形式), 表明预撑剂在磷酸锆层板间的流动性是影响卟啉嵌入的一个重要因素. 另外, 结合XRD、红外、可见吸收等实验数据和α-磷酸锆层板高电荷密度的特性, 我们可推算出: TMPyP以自由碱的形式呈单层倾斜方式紧密堆积在α-磷酸锆层板间.     

超声化学法制备高岭土/二甲亚砜插层复合物的研究

采用与传统方法不同的超声化学法,用二甲亚砜(DMSO)对高岭土进行插层,大大缩短了处理时间,而且达到了较理想的插层效果。采用X -衍射研究插层间距,发现硅酸盐片层间距从0.714 nm增加至1.123 nm左右,插层率为90.9%,并对不同超声条件对插层率的影响进行了探讨。同时用FT-IR和TG/DTA等方法对插层机理进行了分析和研究。     

磷钨酸插层MgAl水滑石层间距的调变及催化酯化脱酸性能

通过改变离子交换温度和时间合成了具有不同层间距的磷钨酸(H_3PW_(12)O_(40),HPW)插层MgAl水滑石(LDHs),采用XRD、FT-IR、Raman、~(31)P MAS NMR、ICP-AES和Hammett指示剂-正丁胺滴定法等表征其性质,并研究其对模型原油的催化酯化脱酸性能。高的离子交换温度有利于形成较大的层间距(d_(003)约1.46 nm),较长的交换时间有利于形成较小的层间距(d_(003)约1.05 nm)。不同的层间距源自HPW在层间不同的存在形式,P_2W_(18)O_(62)~(6-)以C_2轴倾斜于层板和PW_(11)O_(39)~(7-)以C_2轴垂直于层板的方式排列于层间时,形成d_(003)约1.46 nm的层间距;PW_(12)O_(40)~(3-)与层板发生嫁接,并以C_2轴垂直于层板的方向排列于层间时,形成d_(003)约1.05 nm的层间距。层间P_2W_(18)O_(62)~(6-)和PW_(11)O_(39)~(7-)能产生更高比例的中强酸中心,同时大的层间距有利于反应物扩散进入层间与酸中心接触,能够提高LDHs的催化酯化脱酸性能。     

铵离子插层mos2的制备与表征

以剥层重堆法制备了NH 4/MoS2插层复合物,该复合物可以作为长期储存的单层MoS2,同时也可作为先驱体以便插入其它客体分子制成新的插层复合物.通过XRD、热重分析和元素分析等测试技术对该插层复合物进行了表征.结果表明,MoS2经NH 4插层后,其层间距由0.615nm增加到0.954nm,由元素分析和热重分析得出插层复合物的组成分别为(NH 4)3.1 MoS2 和(NH 4 )2.9 MoS2 . 插层复合物在空气中放置30 d后,其XRD和热重分析的结果表明该插层复合物的储存稳定性良好. 此外,插层复合物的插层程度受氯化铵溶液浓度、反应温度、反应时间等反应条件的影响,质量分数为1.0%的氯化铵溶液, 反应温度30 ℃和反应时间12 h,所得到的NH 4 /MoS2插层复合物层间距最大.     

高岭石-硬脂酸插层复合物的制备及结构模型的提出

以张家口高岭土为原料,通过直接插层与取代相结合的方法制备高岭石-硬脂酸插层复合物。利用X射线粉末衍射、红外光谱、热重及透射电子显微镜对制备产物进行表征。结果表明:硬脂酸插入到高岭石层间,高岭石层间距d001值由0.72 nm增加到4.05~4.37 nm,插层率达到86.9%;反应时间和溶液p H值会对高岭石-硬脂酸插层复合物的层间距及插层率产生影响;甲氧基嫁接在高岭石表面,与硬脂酸分子同时存在于高岭石层间。高岭石经甲醇改性后脱羟基温度明显降低,高岭石羟基活性提高;高岭石-硬脂酸插层复合物的稳定温度在160℃以下。经过硬脂酸插层改性后的高岭石片层,从边缘开始出现卷曲现象,并且部分长条状片层形成类似埃洛石相的纳米卷;对硬脂酸插层高岭石的作用机理进行分析,结合结构计算,提出高岭石-硬脂酸插层复合物的结构模型,该模型可以解释高岭石-硬脂酸插层复合物在不同条件制备产物层间距变化的原因。     

Intercalation behavior of amino acids into Zn-Al-layered double hydroxide by calcination-rehydration reaction

The intercalation of amino acids for the Zn-Al-layered double hydroxide (LDH) has been investigated by the calcination-rehydration reaction at 298 K using mainly phenylalanine (Phe) as a guest amino acid. The Zn-Al oxide precursor prepared by the calcination of Zn-Al-carbonated LDH at 773 K for 2 h was used as the host material. The amount of Phe intercalated by the rehydration was remarkably influenced by the initial solution pH and reached ca. 2.7 times for anion exchange capacity (AEC) of the LDH at neutral and weak alkaline solutions, suggesting that Phe was intercalated as amphoteric ion form into the LDH interlayer. As Phe is intercalated for the LDH as monovalent anion in alkaline solution, the amount of Phe intercalated at pH 10.5 corresponded with AEC of the LDH. The solid products were found to have the expanded LDH structure, which confirmed that Phe was intercalated into the LDH interlayer as amphoteric ion or anion form. The basal spacing, d₀₀₃, of the Phe/LDH was 1.58 nm at pH 7.0 and 0.80 nm at pH 10.5; two kinds of expansion suggested for Phe in the interlayer space as vertical (pH 7.0) and horizontal (pH 10.5) orientations. The intercalation behavior of various amino acids for the LDH was also found to be greatly influenced by the feature of the amino acid side-chain, namely, its carbon-chain length, structure and physicochemical property. In particular, α-amino acids possessing a hydrophobic or negative-charged side-chain were preferentially intercalated for the LDH.     

Synthesis and UV absorption properties of 2,3-dihydroxynaphthalene-6-sulfonate anion-intercalated Zn-Al layered double hydroxides

An organic UV absorbent has been intercalated into a layered double hydroxide (LDH) host by ion exchange of a Zn-Al-LDH-nitrate precursor with a solution of 2,3-dihydroxynaphthalene-6-sulfonic acid (DNSA) sodium salt in water. After intercalation of the UV absorbent, the powder X-ray diffraction (XRD) pattern shows that the interlayer distance in the LDHs increases from 0.90 to 1.59 nm. The possible structure is that the interlayer DNSA anions arrange in a monolayer and in a perpendicular orientation toward the hydroxide layers. Infrared spectra and TG-DTA curves reveal the presence of a complex system of supramolecular host-guest interactions between layers. The thermal stability of the intercalated UV absorbent was investigated by TG-DTA and it was found that this material is more stable than the original organic UV absorbent at high temperature, showing that the thermostability is markedly enhanced after intercalation into the LDH host. The UV absorbent-intercalated LDHs exhibit excellent UV photostability in polypropylene composites.     

Intercalation of poly(oxyethylene) alkyl ether into a layered silicate kanemite

Poly(oxyethylene) alkyl ether (CnEOm) is intercalated into the interlayer space of a layered silicate kanemite by using layered hexadecyltrimethylammonium (C16TMA) intercalated kanemite (C16TMA-kanemite) as the intermediate. C16TMA-kanemite was treated with an aqueous solution of C16EO10, and the intercalation of C16EO10 was confirmed by the slight increase in the basal spacing (from 2.92 to 3.34 nm) with the increase in the carbon content, yielding C16EO10-C16TMA-kanemite. The product was dispersed again in a C16EO10 aqueous solution, and then 1.0 M HCl was added to the suspension to remove C16TMA ions completely. The basal spacing was further increased (from 3.34 to 5.52 nm) and the content of nitrogen was virtually zero, indicating further intercalation of C16EO10 molecules and complete elimination of C16TMA ions simultaneously. Though C16EO10 molecules are not directly intercalated into kanemite, the mutual interactions among C16TMA ions, C16EO10 molecules, and the interlayer silicate surfaces effectively induce the intercalation of C16EO10. C16EO10-kanemite shows a reversible adsorption of n-decane and water owing to the hydrophobicity and hydrophilicity of C16EO10, respectively, in the interlayer space. Layered CnEO10-kanemites (n = 12 and 18) were also synthesized in a manner similar to layered C16EO10-kanemite.     

Sugar-anionic clay composite materials: intercalation of pentoses in layered double hydroxide

The intercalation of non-ionized guest pentoses (ribose and 2-deoxyribose) into the Mg-Al and Zn-Al layered double hydroxides (LDHs) was carried out at 298 K by the calcination-rehydration reaction using the Mg-Al and Zn-Al oxide precursors calcined at 773 K. The resulting solid products reconstructed the LDH structure with incorporating pentoses, and the maximum amount of ribose intercalated by the Mg-Al oxide precursor was approximately 20 times that by the Zn-Al oxide precursor. The ribose/Mg-Al LDH was observed to have the expanded LDH structure with a broad (003) spacing of 0.85 nm. As the thickness of the LDH hydroxide basal layer is 0.48 nm, the interlayer distance of the ribose/Mg-Al LDH is 0.37 nm. This value corresponds to molecular size of ribose in thickness (0.36 nm), supporting that ribose is horizontally oriented in the interlayer space of LDH. The maximum amount of ribose intercalated by the Mg-Al oxide precursor was approximately 5 times that of 2-deoxyribose. Ribose is substituted only by the hydroxyl group at C-2 position for 2-deoxyribose. Therefore, the number of hydroxyl group of sugar is essentially important for the intercalation of sugar molecule into the LDH, suggesting that the intercalation behavior of sugar for the LDH was greatly influenced by hydrogen bond between hydroxyl group of the intercalated pentose and the LDH hydroxide basal layers.     

Evaluation of hexaniobate nanoscrolls as support for immobilization of a copper complex catalyst

In this work, we report the intercalation properties of the hexaniobate nanoscrolls toward insertion of 2-[2-(2-pyridyl)ethylimino-1-ethyl]pyridine-imidazole copper(II), [Cu(apip)imH]2+, a cationic complex able to promote the catalytic oxidation of organic substrates. Hexaniobate was first transformed into its acidic phase, H2K2Nb6O17, and then exfoliated with n-butylamine in water. The copper complex was immobilized into the nanoscrolls obtained by the acidification of delaminated particle dispersion at pH 3. TEM micrographs of particles after immobilization of the cationic complex show scrolls with external diameters of ca. 25-30 nm and wall thicknesses of about 4.5-7.0 nm. The basal spacing (d(040)) of the copper complex intercalated in hexaniobate is about 11.6 A. The estimated composition, [Cu(apip)imH](0.5)HK2Nb6O17.6H2O, indicates that 50% of the negative charge of interlayer I was neutralized by the copper complex. EPR and IR spectra showed that the ligands and the distorted tetragonal structure of the complex were maintained after immobilization into niobate. The reactivity of this new material toward catechol oxidation using hydrogen peroxide as the oxidizing agent was investigated and compared to the activity of the same complex in solution. The heterogeneous catalyst is initially less effective toward the catechol oxidation but with time, the reaction shows a higher catechol conversion (ca. 82%) than the same copper complex in homogeneous media (ca. 75%). A better reactivity of the heterogeneous catalyst may be related to the stabilization of the immobilized catalyst, preventing its degradation during the reaction course. EPR results show that the kinetics of formation of the DMPO/*OH adduct in homogeneous and heterogeneous conditions corresponds to that observed in the catechol oxidation, suggesting that hydroxyl radicals are involved in the reaction mechanism.     

Intercalation of non-aromatic heterocyclic amines into layered zirconium glycine-<Emphasis Type="Italic">N,N</Emphasis>-dimethylphosphonate

New materials were prepared by intercalation reactions between layered zirconium glycine-N,N-dimethylphosphonate (ZGDMP) and non-aromatic heterocyclic amines: piperazine, piperidine, and morpholine. X-ray powder diffraction patterns showed that the entrance of piperazine, piperidine, and morpholine caused an interlayer expansion of 0.40 nm, 0.66 nm, and 0.67 nm, respectively. The infrared spectra were in agreement with an acid-base reaction, involving layered acid host COOH of ZGDMP and basic center atoms of guest molecules. Thermogravimetric curves revealed thermal stability of the intercalation compounds and content of the inserted amine molecules. These results indicate that non-aromatic heterocyclic amines were intercalated into the galleries of host ZGDMP.     

Stable UV absorption material synthesized by intercalation of squaric acid anion into layered double hydroxides

A novel UV absorption material of squaric acid (SA) anion (O₄O₄^2?) intercalated layered double hydroxides (LDHs) was successfully synthesized by the co-precipitation method. After intercalation, the interlayer distance of MgAl-SA-LDHs increased to 1.04 nm compared to those of MgAl-CO₃-LDHs and SA anions present in form of a monolayer in the interlayer of LDHs. Thermal stability of SA clearly enhanced by the intercalation and the suppression of the deintercalation ability of MgAl-SA-LDHs was superior to that of 4-hydroxy-3-methoxybenzoic acid intercalated LDHs. The results of UV-DRS indicate the potential application of MgAl-SA-LDHs as UV absorbers.