Solid base reagents

Unloaded silica does not recover HPA from aqueous solution. The surface of silica gel modified with quarternary ammonium salts (QAS) gets anion-exchange properties. The aim of the work is the elaboration of solid-phase reagents on the base of ion associate of HPA with QAS immobilized onto silica surface for the determination of phosphoms and organic reductants. Heterocyclic (safranine and lucigenine) and aliphatic (trinonyloctadecyl ammonium iodide and tetradecyl ammonium nitrate) compounds have been examined as QAS. 

Brombenztiazo (BBT) is known to be one of the best reagents for extraction-photometric determination of cadmium(II). The reagent also fonus complexes with Co(II), Cu(II), Fe(II), Ni(II), Zn(II). The aim of this work was to develop a solid-phase reagent on the base of BBT immobilized on silica gel for sorption-spectroscopic and visual test determination of Cadmium, and also for soi ption-atomic-adsoi ption determination of total heavy metals contents in natural waters. 

In the present work, the technique of XO and MTB immobilization onto silica gel in the form of its complexes with Fe(III) and Bi(III) respectively were found. The acid - base and chemical-analytical characteristics of solid-phase reagents were examined. The optimal conditions of quantitative recovery of Pb(II) and Zn(II) from diluted solutions, such as acidity of aqueous phase, the mass of the sorbents, the volume of solutions and the time of equilibrium reaching, were found. The methods of and F" detenuination were based on a competitive reactions of Zr(IV) with immobilized MTB and or F". Optimal conditions of 0,0 and F" determination in solution using SG, modified ion associates QAS-MTB (pH = 1,5, = 5-10 mol/1). 

MODELING OF ELECTROCHEMICAL PROCESSES IN THE ELECTRODES BASED ON SOLID ACTIVE REAGENTS AND CONDUCTIVE CARBON ADDITIVES... 

The solid bases CaO and hydroxyapatite catalyze the hydrosilylation of benz-aldehyde by triethoxysilane at 90° in yields of 59% and 72% within one and two hours, respectively.323,324 These reductions also very likely involve activation by valence expansion of the silicon hydride reagent. 

Base is to be avoided in this reaction as it facilitates breakdown of the intermediate to form the chloroalkane rather than having it remain as the ester. Alternatively, the solid phosphorus reagent PC15 may be used, but two equivalents of alcohol are required the first is converted to chloroalkane with concomitant formation of P(0)C13, with which the second equivalent of alcohol can react to generate the desired product, the alkyl phosphorodichloridite.3... 

The mild conditions employed for the activation of sulfoxides, and the high reactivity of the glycosyl donor, suggested that the method might translate well to the solid phase. Moreover, the nonpolar nature of the sulfoxide, triflic anhydride, and DTBMP (solution-based reagents) should enable them to partition effectively into a non-polar, polystyrene-based resin. 

Oleschuk, R. D., L. L. Shultz-Lockyear, Y. Ning, and D. J. Harrison. Trapping of bead-based reagents within microfluidic systems On-chip solid-phase extraction and electrochromatography. Anal. Chem. 72, 585-590 (2000). 

The incorporation of Fmoc-Phe[CF2PO(OEt)2]-OH in Fmoc-based solid-phase synthesis is readily performed using DIC/HOBt, PyBOP, and other uronium-based reagents (HBTU, HATU). The deprotection of the peptide-resin is effected by the one-step treatment of the... 

Ando T, Inorganic solid supported reagents as acids and bases, Stud. Surf. Sci. Catal., 90 9-20, 1994. 

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