scholarly journals Nano-ion-exchangers - a new class of reactive materials

2018 ◽  
Vol 18 (6) ◽  
pp. 794-809
Author(s):  
Anatoly M. Dolgonosov ◽  
Ruslan Kh. Khamizov ◽  
Nadezhda K. Kolotilina
Keyword(s):  
Solid Phase ◽  
Ionic Composition ◽  
Photo Luminescence ◽  
Colloidal Systems ◽  
Ion Exchangers ◽  
New Class ◽  
Counter Ions ◽  
Dynamic Experiments ◽  
Back Ground ◽  
Charged Ions

Nano-sized particles of functional polymers i.e. nano-ion-exchangers (NIEX), are unusual objects which simultaneously behave as the hyper-charged ions and the solid ion exchangers. Due to similar charges, they form very stable colloidal systems. This paper is devoted to theoretical and practical study of the proper- ties of nano-exchangers, methods for their preparation, the technique of experiments being practically un- known, and the opportunities for their application. The results of dynamic experiments are given for sorption of nano-exchangers and the ions of back- ground solutions on the beds of macro-particles of usual cationic and anionic resins. It is shown how to ob- tain the NIEX hydrosols with the desired ionic composition, and the concept of the standard state hydrosol is defined. The possibility for solid-phase exchange of counter ions between contacting particles of the same polarity is demonstrated. The possibilities and advantages of using nano-ion-exchangers in chemical analysis are demonstrat- ed by different examples: preparation of separating phases for ion chromatography, application as modifier in capillary electrophoresis and using in photo-luminescence. The prospects of nano-ion-exchangers for drug delivery are also shown.

Glycosyldisulfides: a new class of solution and solid phase glycosyl donors

2001 ◽  
pp. 189-190 ◽  
Author(s):  
Benjamin G. Davis ◽  
Sarah J. Ward ◽  
Phillip M. Rendle
Keyword(s):  
Solid Phase ◽  
New Class ◽  
Glycosyl Donors

scholarly journals Inorganic Nanostructured Anion-Exchange Materials Based on Aluminum Hydroxide

2020 ◽  
Vol 4 (3) ◽  
Keyword(s):  
Anion Exchange ◽  
Aluminum Hydroxide ◽  
Solid Phase ◽  
Structural Motif ◽  
Dynamic Mode ◽  
Isomorphic Substitution ◽  
Ion Exchangers ◽  
Oh Groups ◽  
Wide Range ◽  
Exchange Properties

Inorganic sorbents, in comparison with ordinary organic ion exchangers, have higher selectivity, radiation, thermal, and chemical stability. Inorganic ion exchangers are universal materials exhibiting both cation exchange and anion exchange properties. In this work, using aluminum hydroxide (AHO) as an example, we study the possibility of expanding the range of metal oxyhydrates that can serve as the basis to produce inorganic anion-exchange materials. The properties of aluminum hydroxide largely depend on the method of its production. This phenomenon is associated with a different state of Al3+ ions in aqueous solutions during hydrolysis. Estimation of the size of the primary particles of hydrated alumina gives a value of 19 nm. The most potent effect on the structure and ion-exchange properties of aluminum hydroxide is exerted by the introduction of alloying elements into its composition. Isomorphic substitution of a part of Al(III) ions in the structure of aluminum hydroxide with ions with a higher charge (Ti(IV), Zr(IV), or W(VI)) leads to an increase in the content of exchangeable OH-groups in the resulting material. The synthesized materials are amorphous substances, to study their structure; the method of diffuse X-ray scattering was used. The Gibbsite structural motif is determined, and structural changes occurring under the influence of various factors, and synthesis conditions are analyzed. By optimizing the composition of the material, it is possible to improve its sorption characteristics significantly. AAW-0, AAZ-0, and AAT-0 anion exchangers synthesized based on hydrated aluminum oxide can be used to purify weakly acidic electrolyte solutions from anionic impurities in the dynamic mode of repeated sorptiondesorption cycles. Materials based on mixed hydrated oxides of various elements can also be used as catalyst supports. Their anion exchange properties allow a wide range to vary the number of different anions introduced into the solid phase and, accordingly, to regulate the number and state of active catalytic sites.

scholarly journals Peptidines: glycine-amidine-based oligomers for solution- and solid-phase synthesis

2016 ◽  
Vol 7 (5) ◽  
pp. 3317-3324 ◽  
Author(s):  
Julian Vastl ◽  
Rendy Kartika ◽  
Kichul Park ◽  
Art E. Cho ◽  
David A. Spiegel
Keyword(s):  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Phase Synthesis ◽  
New Class ◽  
Synthetic Procedure

We introduce a modular synthetic procedure to produce a new class of synthetic oligomers called peptidines composed of repeating di-substituted glycine-derived amidines.

Polymer-bound mixed carboxylic dithiocarbamic anhydrides. A new class of selective and recyclable solid-phase acylating reagents

1987 ◽  
Vol 52 (13) ◽  
pp. 2662-2665 ◽  
Author(s):  
V. K. Haridasan ◽  
A. Ajayaghosh ◽  
V. N. Rajasekharan Pillai
Keyword(s):  
Solid Phase ◽  
New Class

ChemInform Abstract: Glycosyldisulfides: A New Class of Solution and Solid Phase Glycosyl Donors.

ChemInform ◽  
2001 ◽  
Vol 32 (19) ◽  
pp. no-no
Author(s):  
Benjamin G. Davis ◽  
Sarah J. Ward ◽  
Phillip M. Rendle
Keyword(s):  
Solid Phase ◽  
New Class ◽  
Glycosyl Donors

Possible Roles of Partial Sequences at N- and C-termini of Amelogenin in Protein-Enamel Mineral Interaction

1989 ◽  
Vol 68 (9) ◽  
pp. 1331-1336 ◽  
Author(s):  
T. Aoba ◽  
E.C. Moreno ◽  
M. Kresak ◽  
T. Tanabe
Keyword(s):  
Crystal Growth ◽  
Adsorption Isotherm ◽  
Inhibitory Activity ◽  
Solid Phase ◽  
Ionic Composition ◽  
Significant Inhibition ◽  
Apatite Crystal ◽  
Supersaturated Solution ◽  
Adsorption Sites ◽  
Adsorption Affinity

The purpose of this study was to assess the functional significance of homologous sequences of mammalian amelogenins at their N- and C-termini. A porcine 5-kDa fragment corresponding to the N-terminal 45 residues of amelogenins was purified from the secretory enamel. The decapeptide TDKTKREEVD corresponding to the C-terminal 10 residues of amelogenins was synthesized according to conventional solid-phase procedures. The inhibitory activity of both moieties on apatite crystal growth was determined in a supersaturated solution having an ionic composition similar to that of the fluid phase separated from porcine secretory enamel. The 5-kDa amelogenin fragment was sparingly soluble in neutral solutions and (in condensed forms because of aggregation) showed no significant inhibition of crystal growth, whereas the fragment molecules pre-adsorbed onto the seed crystals yielded modest inhibition of hydroxyapatite precipitation. However, their inhibitory activity was significantly lower than that of parent porcine amelogenin (25-kDa molecular mass). The high solubility of synthesized decapeptide allowed us to determine the adsorption isotherm onto hydroxyapatite at 37°C, at an ionic strength similar to that of the enamel fluid. The obtained adsorption isotherm was described by a Langmuir model; the adsorption affinity and the maximum adsorption sites were 6.2 mL/μmol and 0.53 μmol/m2, respectively. As expected from the low adsorption affinity, the peptide showed a much weaker inhibition of apatite crystal growth than the parent amelogenin. All the foregoing results suggest that the adsorption onto apatite crystals and any inhibition of crystal growth by the amelogenin macromolecules cannot be associated with either partial molecular sequence, but may be determined by the whole molecular structure, including both segments at the N- and C-termini.

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