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1.
运用γ-巯丙基三乙氧基硅烷对硅胶表面硫醇化修饰改性,红外及拉曼光谱分析表明硅胶的表面硫醇化借助硅胶表面羟基与γ-巯丙基二乙氧基硅烷间的化学键联实现。实验条件下改性硅胶对水体罗丹明B的吸附性能明显提升,改性硅胶表面罗丹明B的吸附动力学符合准二级动力学模型,吸附等温线服从Langmuir等温线规律,由等温吸附计算得到的热力学函数变化表明吸附系自发、放热过程。吸附动力学、热力学及光谱表征均表明改性硅胶上罗丹明B的吸附主要为其在改性硅胶表面借助电价和共价键联的化学吸附。  相似文献   

2.
运用γ-巯丙基三乙氧基硅烷对硅胶表面硫醇化修饰改性, 红外及拉曼光谱分析表明硅胶的表面硫醇化借助硅胶表面羟基与γ-巯丙基二乙氧基硅烷间的化学键联实现。实验条件下改性硅胶对水体罗丹明B的吸附性能明显提升, 改性硅胶表面罗丹明B的吸附动力学符合准二级动力学模型, 吸附等温线服从Langmuir等温线规律, 由等温吸附计算得到的热力学函数变化表明吸附系自发、放热过程。吸附动力学、热力学及光谱表征均表明改性硅胶上罗丹明B的吸附主要为其在改性硅胶表面借助电价和共价键联的化学吸附。  相似文献   

3.
采用原子层沉积技术, 在3~5 kPa真空和125~150 ℃ 的反应条件下, 使γ-巯丙基三甲氧基硅烷(MPTMS)、γ-巯丙基三乙氧基硅烷(MPTES)和γ-巯丙基二甲氧基甲基硅烷(MPDMMS)3种巯丙基硅烷试剂气化, 并在三乙胺的催化作用下, 分别将其键合于多孔硅胶表面, 制得贵金属钯(Ⅱ)的高效吸附剂. 分别采用FTIR、13C和29Si固体核磁、元素分析、热重分析和氮气吸附-脱附等技术研究了巯基硅胶的键合模式和功能基团键合量. 用分光光度法研究了在pH=3.0条件下水溶液中Pd(Ⅱ)离子在巯基硅胶上的吸附行为. 结果表明, 在MPTMS, MPTES和MPDMMS所修饰的硅胶中, 硅烷试剂的功能基团均以双齿键合结构为主, 表面键合量分别达到2.76, 2.53和2.70 μmol/m2. 对Pd(Ⅱ)离子的吸附遵从Langmuir等温吸附方程, 饱和吸附量分别达到5.45, 4.21和4.81 μmol/m2, Pd/S的摩尔比分别为1.44, 1.35和1.39. 原子层沉积法制备的巯丙基硅胶基质钯吸附剂的巯基键合密度和对钯(Ⅱ)离子的吸附容量均比传统的有机溶剂介质法高.  相似文献   

4.
本文以硅胶为载体,通过氯丙基三乙氧基硅烷(CPTS)将2-氨基吡啶负载到硅胶表面,得到硅胶负载氨基吡啶(SG-AP)吸附材料,通过红外光谱、元素分析对其结构进行了表征。研究了SG-AP对Ag+的吸附性能,考察了溶液pH值、接触时间、温度及金属离子初始浓度等因素对吸附性能的影响。结果表明,对Ag+的最佳吸附pH值为6。吸附动力学表明,对Ag+的吸附符合准二级动力学模型,为液膜扩散控制过程。等温吸附表明吸附过程可用Langmuir模型描述,为单分子层吸附。SG-AP对Ag+吸附的热力学参数表明,吸附过程是自发、吸热的过程。  相似文献   

5.
γ-巯丙基三乙氧基硅烷与丙烯腈加成,得到γ-(β-氰乙硫基)丙基三乙氧基硅烷,后者依次与气相法二氧化硅、三氯化铑作用,合成了聚γ-(β-氰乙硫基)丙基硅氧烷铑配合物,研究了其催化烯烃与三乙氧基硅烷硅氢加成反应的特性。  相似文献   

6.
本文以柱层层析硅胶为原料,用γ-氨丙基三甲氧基硅烷对其表面进行修饰,制得氨基键合硅胶微粒,进而在碱性条件下与二硫化碳反应,合成二硫代氨基甲酸键合硅胶(DTC-SiO2)。以Cu2+为吸附对象,考察DTC-SiO2对金属离子的吸附性能,探讨了溶液pH值、吸附剂用量、初始Cu2+浓度、吸附时间等影响材料吸附效果的因素,并研究了吸附剂对Cu2+的吸附等温线和动力学吸附特性。结果表明,在温度298K下,DTC-SiO2对Cu2+的吸附符合Langmuir等温式,准二级吸附动力学方程能够很好地描述Cu2+在DTC-SiO2上的吸附动力学行为。  相似文献   

7.
采用γ-氨丙基三乙氧基硅烷对硅胶微球表面进行接枝修饰,然后以甲基丙烯酸为功能单体,二甲基丙烯酸乙二醇酯为交联剂,甲苯为溶剂,3-甲基噻吩为模板分子,在硅胶微球表面聚合,得到3-甲基噻吩的硅胶微球表面分子印迹聚合物,用红外光谱进行结构表征。通过考察模板分子、功能单体、交联剂、溶剂的用量等对吸附容量的影响,得到3-甲基噻吩、甲基丙烯酸、二甲基丙烯酸乙二醇酯、甲苯适宜的摩尔聚合比,以此配比合成了3-甲基噻吩表面印迹聚合物,在模拟汽油中,研究了该聚合物对3-甲基噻吩的吸附动力学、吸附选择性、竞争性及再生性能。结果表明,分子印迹聚合物对3-甲基噻吩具有良好的吸附选择性和再生性能,最大吸附容量可达85mg/g,有望将其用于汽油中噻吩类硫的深度脱除,从而弥补加氢脱硫缺陷。  相似文献   

8.
γ-巯丙基三乙氧基硅烷与丙烯腈加成,得到γ-(β-氰乙硫基)丙基三乙氧基硅烷,后者依次与气相法二氧化硅,三氯化铑作用,合成了聚γ-(β-氰乙硫基)丙基硅氧烷铑配合物,研究了其催化烯烃与三乙氧基硅烷硅氢加成反应的特性。  相似文献   

9.
γ-巯丙基三乙氧基硅烷与丙烯腈反应,得到γ-(β-氰乙硫基)丙基三乙氧基硅烷.后者经气相法二氧化硅固载,再与氯亚铂酸钾反应,合成了聚γ-(β-氰乙硫基)丙基硅氧烷铂配合物.研究了该铂配合物对不饱和烃与三乙氧基硅烷的硅氢加成反应的催化特性.  相似文献   

10.
以γ-巯丙基三乙氧基硅烷与己酰氯为单体,在N2保护与低温下合成偶联剂3-己酰基硫代-1-丙基三乙氧基硅烷(HXT),将HXT与双-(3-乙氧基硅基丙基)二硫化物(TESPD)分别添加于溶液聚合丁苯橡胶(SSBR)/SiO2混炼胶复合体系中.采用流变学方法表征复合体系的动态粘弹行为,发现HXT可改善填料和基体的相互作用,有效阻止SiO2粒子在加工过程中的团聚.与TESPD相比较,含HXT体系具有较高“Payne效应”临界应变值.  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

14.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

15.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

16.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

17.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

18.
19.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

20.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

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