共查询到20条相似文献,搜索用时 78 毫秒
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以2-羟基-1,3-丙二胺和2,6-二甲酰基-4-R-苯酚(R=CH3、Cl)通过Pb2+作模板进行缩合反应制备了四亚胺双酚双核Pb(II)配合物,再用硝酸Tb(III)置换Pb(II)离子,合成了单核Tb(III)配合物[Tb(III)(H4L)(NO3)2(H2O)](NO3).2(H2O),最后再弱碱性条件下用三联吡啶置换其中的一个NO3-和一个H2O,得到目标配合物[Tb(H3L)(NO3)(C5H3N(C5H4N)2)](NO3).H2O,获得了单晶结构,并进行了晶体结构分析和系统物理表征。 相似文献
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利用不同比例的高岭土和硅藻土为原料通过原位晶化方法合成出了结晶度较高的NaY分子筛,采用X射线衍射仪、扫描电子显微镜、N2吸附–脱附等测试手段对合成样品进行了表征。着重考察了m(高岭土):m(硅藻土)(质量比,下同)为6:4和2:8两种比例下,晶化合成体系中n(SiO2):n(Al2O3)(摩尔比,下同)、n(Na2O):n(SiO2)和n(H2O):n(Na2O)对原位晶化产物性能的影响。结果表明:在m(高岭土):m(硅藻土)为6:4的合成体系中,随n(SiO2):n(Al2O3)的增大,NaY分子筛的相对结晶度先增大后减小,增大体系的n(Na2O):n(SiO2)和减小n(H2O):n(Na2O)都有利于产品相对结晶度的提高;在m(高岭土):m(硅藻土)为2:8的合成体系中,增大n(SiO2):n(Al2O3),NaY分子筛的相对结晶度先增大后减小,但增大n(Na2O):n(SiO2)和减小n(H2O):n(Na2O),NaY分子筛的相对结晶度减小。 相似文献
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为研究复合物的结合能、二阶稳定化能及氧键中的四种相互作用E(elect)、E(polar)、E(vdw)、(E(orbit),本文运用密度泛函理论B3LYP方法和二阶微优理论MP2方法,选取碱基尿嘧啶(U)与系列小分子形成的氮键二聚物为研究对象为例进行了分析。实验表明,碱基尿嘧啶的一号位点、二号位点、三号位点分别与系列小分了作用彤成的氯键二聚体的结合能(BE)与E(elect)、(E(elect)+E(vdw))、(E(elect)+E(vdw)+E(polar))等的差值与二阶稳定化能(Eij)没有很好的线性关系,但结合能(BE)与二阶稳定化能(Eij)有线性相关。 相似文献
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乙醇胺催化合成乙撑胺的研究 总被引:1,自引:0,他引:1
以乙醇胺(MEA)为原料,ZSM-5分子筛为催化剂,采用缩合工艺合成了乙撑胺。考察了反应温度、n(NH3)∶n(MEA)及空速LHSV(MEA)对乙醇胺的影响。反应所用原料为质量分数50%的乙醇胺溶液。为增加乙二胺(DEA)和哌嗪(PIP)的选择性,适宜的条件为:n(NH3)∶n(MEA)=13,LHSV(MEA)=0.300 h-1,反应温度350℃,选择性S(DEA)=17.78%,S(PIP)=20.46%,S(TE-DA)=21.99%,转化率约为70%。 相似文献
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建立了搅拌棒吸附萃取-热脱附/气相色谱-质谱法分析可可提取物挥发性成分的方法,其中,PDMS型搅拌磁子检出72个化合物,峰面积相对百分比大于1%的化合物有:异戊酸(25.28%)、异戊醛丙二醇缩醛(14.57%)、乙酸苄酯(10.60%)、1,2-丙二醇(9.17%)、苯乙醇(9.00%)、二苯丙酮(5.00%)、苯乙酸苯乙酯(4.50%)、异戊酸异戊酯(3.63%)、2,3,5-三甲基吡嗪(2.34%)、2-甲氧基-3-甲基吡嗪(2.29%)、可可醛(1.53%)、亚油酸乙酯(1.25%)和乙酸(1.10%),EG-Silicone型磁子检出57个化合物,峰面积相对百分比大于1%的化合物有:2,3,5-三甲基吡嗪(63.59%)、乙酸(12.06%)、异戊醛丙二醇缩醛(4.96%)、乙酸苄酯(3.92%)、棕榈酸(1.89%)、愈创木酚(1.41%)、异戊酸(1.08%)、二苯丙酮(1.08%)和甘油(1.01%),并对致香机理进行了探讨。研究结果为可可提取物的开发、调香应用和质量监控提供了依据。 相似文献
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介绍了PVC用水滑石类化合物(LDHs)热稳定剂的制备方法,作用机理以及应用进展,指出了其今后的发展方向。 相似文献
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采用共沉淀法制备纳米Mg-Al-LDHs水滑石,并以纳米Mg-Al水滑石为前体,采用返混沉淀法进行插层组装,合成酒石酸根阴离子柱撑水滑石。采用红外光谱、X射线衍射对样品进行了表征。结果表明,酒石酸根阴离子可以插入纳米Mg-Al水滑石层间,完全取代CO32-,形成具有超分子结构的稳定酸根阴离子柱撑水滑石,其尺寸达到纳米级。 相似文献
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A set of synthesized Mg/Co/Al hydrotalcites was synthesized and characterized by XRD, XPS, BET, SEM, TEM, and FT-IR physical techniques. The partial substitution of Mg2 + by Co2 + in brucite layers has not significantly affected the layered double hydroxide structure, but plays a crucial role in the oxidation of styrene in the presence of air. The prepared Mg/Co/Al hydrotalcite-like compounds express a good activity and stability in the oxidation of styrene in the free-solvent condition. Both styrene conversion and desired product selectivities are strongly dependent on the cobalt substitution content. The intra-hydrotalcite lattice Co2 + ions are active sites for the epoxidation of styrene. 相似文献
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利用表面嫁接法将过渡金属元素(Ti、V、Cr、Fe)嫁接到镁铝类水滑石的层板上,运用电感耦合等离子体原子发射光谱、X射线固体粉末衍射和透射电子显微镜等方法对其进行了表征,并以环氧丙烷和甲醇反应为探针反应测试了其碱催化性能。结果表明,嫁接后的镁铝水滑石仍具有良好的层状结构,Ti嫁接的镁铝水滑石比其它过渡金属元素嫁接的镁铝水滑石表现出了更优的催化性能。在适宜条件下,环氧丙烷的转化率为85.3%1,-甲氧基-2-丙醇的选择性可达81.8%。而且,该催化剂的催化性能不受空气中水和二氧化碳的影响,是一种高稳定的固体碱催化剂。 相似文献
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G Stoica I Castelló Serrano A Figuerola I Ugarte R Pacios E Palomares 《Nanoscale》2012,4(17):5409-5419
Quantum dot-hydrotalcite layered nanoplatforms were successfully prepared following a one-pot synthesis. The process is very fast and a priori delamination of hydrotalcite is not a prerequisite for the intercalation of quantum dots. The novel materials were extensively characterized by X-ray diffraction, thermogravimetry, infrared spectroscopy, transmission electron microscopy, true color fluorescence microscopy, photoluminescence, and nitrogen adsorption. The quantum dot-hydrotalcite nanomaterials display extremely high stability in mimicking physiological media such as saline serum (pH 5.5) and PBS (pH 7.2). Yet, quantum dot release from the solid structure is noted. In order to prevent the leaking of quantum dots we have developed a novel strategy which consists of using tailor made double layered hydrotalcites as protecting shells for quantum dots embedded into silica nanospheres without changing either the materials or the optical properties. 相似文献
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Esteban López-Salinas Mayela García-Sánchez Ma. Luisa Ramón-García Isaac Schifter 《Journal of Porous Materials》1996,3(3):169-174
A series of Ga-containing hydrotalcite-like materials (GaHTs), [Mg1-x
Ga
x
(OH)2](CO3)
x/2 ·mH2O wherex = 0.072 0.35 (Mg/Ga = 12.9 1.8), was synthesized by a coprecipitation method. The resulting solids were characterized by means of X-ray diffraction, thermal gravimetric and infrared analyses. All GaHTs showed diffraction patterns typical of Mg-Al hydrotalcites. Small amounts of brucite, Mg(OH)2, were detected only in the GaHT with Mg/Ga = 12.9. Attempts to obtain Ga-richer hydrotalcites, Mg/Ga < 1.8, resulted in solids with an invariably constant Mg/Ga = 1.8 ratio, which appears to be the maximum Ga content limit. Judging from the TGA pattern of a GaHT (Mg/Ga = 7.7), the layered structure is stable up to ca. 573 K, and at 873 K the resulting solid shows a MgO-like diffraction pattern, suggesting that Ga3+ may be replacing some Mg2+ ions in MgO. Once their layered structure collapses (i.e., at 873 K), GaHT can be easily converted back into the original layered material by treating in a carbonate-containing aqueous solution, i.e., they show the memory effect typical of Mg-Al hydrotalcites. 相似文献
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