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941.
SongLI JianXinTANG MeiJuJI PengHOU PengFengXIAO NongYueHE 《中国化学快报》2004,15(7):837-840
A novel substrate for in situ synthesis of oligonucleotide was prepared by hydrolyzing microporous polyamide-6 membranes in a 0.01mol/L NaOH/(H2O-CH3OH) mixture medium. The formation of amines (NH2) on the surface was proved by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The treated membrane was applied for in situ synthesis of oligonucleotide and a single step coupling efficiency determined by ultraviolet (UV) spectra was above 98%. 相似文献
942.
943.
溶剂热合成具有纳米孔结构的γ-Al2O3 总被引:2,自引:0,他引:2
0引言γ-Al2O3又称活性氧化铝,一般具有较高的比表面积,在工业生产中被广泛用作吸附剂和催化剂载体[1],尤其是可作为负载贵金属催化剂的载体[2 ̄4]。纳米级的γ-Al2O3由于颗粒粒径小而在其颗粒表面形成了丰富的失配键和欠氧键,以此制成多孔薄膜作为催化剂及催化剂载体,其性能比目前使用的同类产品性能要优越许多[5]。但纳米级的γ-Al2O3也存在一些缺点,如由于纳米颗粒的表面能较高导致了颗粒的团聚较严重,分散性较差;由于γ-Al2O3活性较高,所以其高温热稳定性不太好,这些缺点极大地限制了γ-Al2O3的应用范围。因此合成具有良好分散性和… 相似文献
944.
QU Rongjun SUN Changmei WANG Chunhua JI Chunnuan WANG Ying CHENG Guoxiang SONG Renfeng 《反应性高分子(英文版)》2003,12(1):78-82
Acetyl crosslinked polystyrene (EPS) and crosslinked bromoacetyl polystyrene (BEPS)beads were synthesized by Fridel-Crafts acetylation of polystyrene (PS) and bromination of EPS respectively. FTIR, XPS, and TG-TDG were employed to characterize their structures. The results revealed there are two types of bromine in the BEPS molecule. One is in the main chain of polystyrene and the other is in the acetyl. The results of TG-DTG showed that the rates of loss weight of PS, EPS, and BEPS were 92.7%, 92.2%, and 81.3% among the 300 ℃~500 ℃; 7.3%, 7.8%, and 18. 7% in 594 ℃, 660 ℃, and 584.8 ℃, respectively. 相似文献
945.
946.
IntroductionTetrathiometallateanions [MS4 ]2 - (M =Mo ,W )andtheirclusterswithvarioustransitionmetalsarewell knownfortheirrichcoordinationchemistry ,1 7andtheirrelationtoindustrialcatalysisprocess ,8biologicalsystems ,9andNLOmaterials .10 12 However,thechemistryoftheorganometallictrisulfidecomplexes [PPh4 ][(η5 C5Me5) MS3](M =Mo ,13W14 )andtheirrelatedmixed metalclus tershavebeenlessinvestigated .15,16 Inordertoextendourknowledgeaboutthechemistryof [PPh4 ][(η5 C5Me5) MS3]andconti… 相似文献
947.
948.
Phosphatdylcholines and their analogs, the functional building block of the membrane, are recently found to mediate multiple physiological processes and exhibit a broad range of desirable pharmacological effects, which involve hydrophobic lipophilic interactions (HLI) between the phospholipid and the cell membrane. The HLI behavior of phosphatJdylcholines (Ln) and their analogues 1, 2-diacyl-sn-glycerol-3-phosphoric acid bromoethyl ester (Pn), have been investigated in MeOH-H20 binary systems of different volume fractions (designated as Φ) of the organic component, by employing α-nephthylethyl lauryl ether (Np-12) as fluorescent probe. A very interesting observation is that the Ln possesses double character, i. e., it behaves both as an aggregator and as a deaggregator. The effects of the structure and the environment on the coaggregation and deaggregtion are also discussed. 相似文献
949.
950.
Recently, methods based exclusively on organic catalysts have become of major significance in synthetic chemistry.Mukaiyama-aldol reaction, as one of the most important and frequently utilized methods for C-C bond formation, is well documented in literatures recently. A variety of reagents, particularly metal-containing Lewis acids or bases, are known to promote the nucleophilic process. However, many of the reported strategies might have the following limitations from environmental viewpoints: (1) the use of metal-containing catalyst. Some of the catalysts are air or moisture sensitive (such as lithium amide), and crucial reaction conditions are needed; Some of the catalysts derived from poisonous metal (for example: SnCl4, SmI2 etc.) may cause harmful influence on humane body and environment; (2) the use of organic solvent (such as DMF, CH2Cl2 etc.) may bring about environmental pollution and solvent waste. 相似文献