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211.
Egbert Müller Judith Vajda Djuro Josic Tim Schröder Romain Dabre Tim Frey 《Journal of separation science》2013,36(8):1327-1334
An essential part of the modulation of protein‐binding capacity in hydrophobic interaction chromatography is the buffer‐salt system. Besides using “single” electrolytes, multicomponent electrolyte mixtures may be used as an additional tool. Both the protein solubility and the binding capacity depend on the position of a salt in the so‐called Hofmeister series. Specific interactions are observed for an individual protein‐salt combination. For salt mixtures, selectivity, recovery, and binding capacity do not behave like for the single salts that are positioned in between the two mixed components in the Hofmeister series, as the continuous correlation would suggest. Thus, finding strategies for mixed salts could potentially lead to improved capacities in hydrophobic interaction chromatography. Mixtures of ammonium sulfate, sodium citrate, sodium sulfate, sodium chloride, sodium acetate, and glycine were used to investigate the binding capacities for lysozyme and a monoclonal antibody on various hydrophobic resins. Resin capacity for two investigated proteins increases when mixtures consisting of a chaotropic and a kosmotropic salt are applied. It seems to be related to the rather basic isoelectric points of the proteins. 相似文献
212.
《高分子科学杂志,C辑:聚合物评论》2013,53(4):389-410
Abstract Polyhedral oligomeric silsesquioxane (POSS), a hybrid nanostructured macromer has been used in the last decade for preparation of polymeric nanocomposites. Its versatile chemistry, which lends it for almost infinite chemical modification, sets it apart from other nanostructured fillers like nanoclays, carbon nanotubes, and carbon nanofibers. Depending on its functionality, 3‐D network, bead or pendant type‐POSS based polymeric nanocomposites can be synthesized. These have the potential to be designed for products with specific nanostructures for specific end‐use applications. This article discusses the trends in current research involving use of POSS macromers for modification of mainly thermal and viscoelastic properties of various polymers. 相似文献
213.
Matthew Polson Mark M. Turnbull Jan L. Wikaira 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(10):1152-1156
The hydrobromide and hydrochloride salts of 2‐amino‐5‐iodopyridine were prepared from aqueous solutions. The hydrobromide salt, C5H6IN2+·Br−·0.5H2O, crystallizes as a hemihydrate, and exhibits hydrogen bonding and π‐stacking which stabilize the crystal structure. The hydrochloride salt, C5H6IN2+·Cl−·H2O·0.375HCl, crystallized as the hydrate and exhibits similar hydrogen bonding and π‐stacking in the lattice. The most interesting feature of the hydrochloride salt is the presence of an additional fractional HCl molecule which introduces disorder in the location of the water molecule. The additional proton from the fractional HCl molecule is accounted for by the presence of a partial hydronium ion on one of the water sites. 相似文献
214.
In the last few years, polymer bioconjugates have been shown to be useful in many emerging areas of materials science. Consequently, the synthesis of polymer bioconjugates has suddenly become a central topic in polymer chemistry. The versatility and robust nature of modern synthetic methods such as controlled radical polymerisation (CLRP),1 ring-opening polymerisation (ROP), and ‘click’ chemistry make them excellent tools for the preparation of tailor-made polymer bioconjugates. CLRP in combination with other techniques has been shown to be a mature technology for building tailor-made block copolymers and protein–polymer conjugates with a wide range of applications, especially in biomedical domains. This review describes the recent advances and progress in the rapidly expanding field of bioconjugation, outlining the work performed up to 2012. 相似文献
215.
The synthesis of nine new carbohydrate-based quaternary ammonium salts and two new triazolium salts starting from d-glucose has been accomplished. Our synthesis utilized the regio- and stereoselective ring opening reaction of 2,3-anhydro sugars by nucleophilic reagents to afford the key intermediates. In these new types of phase transfer catalysts, the ammonium and triazolium functions are directly attached to the carbohydrate scaffold in different positions (2-, 3-, 6-positions of the sugar). The efficiency of the altrose- and glucose-based quaternary salts were tested in the alkylation of N-(diphenyl) methylene glycine tert-butyl ester with benzyl bromide. To our knowledge this is the first example when sugar-based quaternary ammonium or triazolium salts were used successfully as phase transfer catalysts. The enantiomeric recognition ability of the synthesized salts towards racemic Mosher’s acid silver salt was also investigated by 19F NMR spectroscopy. 相似文献
216.
Firouz Matloubi Moghaddam Zohreh Mirjafary Hamdollah Saeidian Behzad Koushki Foroushani Saghar Nourian 《合成通讯》2013,43(13):1941-1949
The synthesis of bicyclo[3.3.1]nonane systems is reported. The synthesis is based on the tandem 1,3-dinucleophilic addition of 4-hydroxy-2-quinolinone to quinolinium salts. 相似文献
217.
《合成通讯》2013,43(17):3071-3076
Abstract The treatment of 4-(2′-hydroxyaryl)-2-(N,N-dialkylamino)-1,3-dithiolium perchlorates (1a–g) with sodium sulfide nonahydrate in ethanol at room temperature affords the corresponding 1,3-dithiole-2-thiones (2a–g). When these reactions are conducted in boiling ethanol, 2′-hydroxyacetophenones (3a–g) have been obtained in good to excellent yield. A tentative mechanism for the formation of 3a–g shows that this reaction is regioselective, this being established by the presence of hydroxyl group in 2′-position. That has been confirmed in a control experiment, 4-phenyl-2-(piperidin-1-yl)-1,3-dithiolium perchlorate affording a mixture of condensation products of acetophenone and phenylacetaldehyde, under similar reaction conditions. 相似文献
218.
Aryl–heteroaryl and heteroaryl–heteroaryl compounds are obtained through the Suzuki–Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl2(CH3CN)2 as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda–Heck reaction between several monoolefins with aryldiazonium salts. 相似文献
219.
The organic/inorganic hybrid nanomaterials containing silica nanoparticles are synthesized by sol-gel crosslinking process. The tetraethoxysilane (TEOS) and γ-aminopropyltriethoxylsilane as coupling agents are used as a precursor. The 2,4,6-tri [(2-epihydrin-3-bimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-EBAC) as crosslinking agent is used to form covalent bonds among the inorganic nanoparticles. The chemical and morphological structures of the organic/inorganic hybrid are characterized with FTIR spectra, 29Si-NMR, x-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and atomic force microscope (AFM). The results show that the organic/inorganic hybrid forms covalent bond between the inorganic nanoparticle and Tri-EBAC. The network organic/inorganic hybrid can form good film with even nanometer particles. The network organic/inorganic hybrids nanomaterial not only exhibits the thermal properties of inorganic compounds, but also exhibits the thermal properties of organic polymer. 相似文献
220.
Kabir‐ud‐Din Suraiya Khatoon Andleeb Z. Naqvi 《Journal of Dispersion Science and Technology》2013,34(4):485-491
Herein we report the effect of additives (salts and organics) on the cloud point (CP) of nonionic surfactant Triton X‐114 (TX‐114) aqueous solutions. CP showed a concentration dependent variation in the absence of any added compound. Addition of quaternary ammonium (or phosphonium) bromides to 0.8 mM TX‐114 solutions increased the CP. It was found that long chain alcohols and amines decreased the CP of 0.8 mM TX‐114 +80 mM Bu4AmB aqueous system, while it either remained constant or increased in the presence of short chain additives. The effect of first group additives (long chain) can be explained by considering that these additives solubilize in interfacial region and assist in micellar growth. Short chain additives remain in aqueous phase and affect the micelle hydration by affecting the solvent. Pentylamine behaved differently than pentanol: pentylamine increased the CP (like short chain additives) while pentanol decreased the CP. In pentylamine, the hydrophilicity of NH2 group and its dissociation into NH3 + dominates over the hydrophobicity of its alkyl chain. Aliphatic hydrocarbons first decreased and then increased the CP. The overall behavior depended upon the chain length of the hydrocarbon. With decane, the CP decreasing region disappeared completely. 相似文献