23978-09-8Relevant articles and documents
Cryptand Exchange Kinetics
Cox, B. G.,Garcia-Rosas, J.,Schneider, H.
, p. 2434 - 2437 (1982)
The rate constants for some reactions between a metal cryptate MCry1n+ and a free cryptand Cry2 has been determined.For the case when Mn+ = Tl+, Ca2+, Cry1 = (2,2,2), (2B,2,2) and Cry2 = (2,2,1) in water or water-methanol mixtures, the observed rate constant correspond to that of the dissociation of MCry1n+.However, the exchange reactions Pb(2,1,1)2+ + (2,2,1) and Pb(2,1,1)2+ + (2,2,2) in MeOH present rates that are much larger than the dissociation rate of Pb(2,1,1)2+.A mechanism involving a bimolecular reaction between cryptate and free cryptand is proposed.
Kinetics of Dissociation of Potassium and Thallium Cryptates
Gresser, R.,Boyd, D. W.,Albrecht-Gary, A. M.,Schwing, J. P.
, p. 651 - 653 (1980)
The kinetics of dissociation of thallium cryptates (222Tl)+ and (221Tl)+ was studied in water and in methanol-water (90:10) over the range of temperatures 5-35 deg C.The kinetic behavoirs of (222Tl)+ and (222K)+ in water were compared.For the direct dissociation process the kinetic results have shown a similar behavior of (222K)+ and (222Tl)+ in water.A less solvating medium (methanol-water) than water leads to slower dissociation rates of the thallium cryptates studied.The acid-catalyzed dissociation path differentiates significantly, in terms of rate constants and activation parameters, the behavior of (222K)+ and (222Tl)+ in acidic aqueous medium.
Complex Formation of Alkaline-Earth Cations with Crown Ethers and Cryptands in Methanol Solutions
Buschmann, Hans-Jurgen
, p. 453 - 462 (1986)
The complexation of alkaline-earth cations by different crown ethers, azacrown ethers, and cryptands has been studied in methanol solutions by means of calorimetric and potentiometric titratios.The smallest monocyclic ligands examined form 2:1 complexes (ratio of ligand to cation) with cations which are too large to fit into the ligand cavity.With the smallest cryptand, only Sr2+ and Ba2+ ions are able to form exclusive complexes.In the case of the reaction of cryptand (211) with Ca2+, a separate estimation of stability constants for the formation of exclusive and inclusive complexes was possible for the first time.Higher values for stability constants are found for the reaction of alkaline-earth cations with cryptands compared to the reaction with alkali ions.This increase is only caused by favorable entropic contributions.
Preparation method of amino polyether (2.2.2)
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Paragraph 0026; 0033-0036; 0038; 0039; 0045-0049; 0050; 0056, (2018/11/27)
The invention belongs to the technical field of cryptand preparation, and concretely relates to a preparation method of amino polyether (2.2.2). The preparation method comprises the following steps: taking triglycol and paratoluensulfonyl chloride as raw materials, triethylene glycol di(p-toluenesulfonate) is obtained through a nucleophilic reaction, and then the material is subjected to a reaction with 2,2'-(ethylenedioxy)di(ethylamine), and through complexation and recrystallization, the amino polyether (2.2.2) is obtained; the reaction condition is mild and simple, a synthesis period can reduced to 27 h, the overall yield is no lower than 49%, and the method has the beneficial effects of short reaction period and high yield.
Photocurable resin composition, dry film thereof, pattern forming method, and electrical/electronic part protective film
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, (2012/05/04)
A photocurable composition includes: (A) an epoxy group-containing polymer compound having repeating units represented by the following formula (1), where R1 to R4 are each a hydrocarbon group, m is an integer of 1 to 100, a, b, c and d are each 0 or a positive number, such that 0 (c+d)/(a+b+c+d) ≤ 1.0, and X and Y are each the formula (2) or (3), provided that at least one group of the formula (3) is present, (B) a photoacid generator represented by the formula (8) and (C) a solvent.
POSITIVE RESIST COMPOSITION AND PATTERNING PROCESS
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, (2010/04/23)
A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R1 is H, methyl or trifluoromethyl, X is a single bond or methylene, m is 1 or 2, and the hydroxyl group attaches to a secondary carbon atom. The composition is improved in resolution when processed by lithography.