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Radkevich, V. Z.; Kistanova, I. E.; Солдатов, В. С.; Egiazarov, Yu. G.

doi:10.1023/a:1013776328520

Cited by 5 publications

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“…While the importance of obtaining precise information on the morphology, size, pore volume, and solvent mobility was already stressed before, , other macroscopic physical forms of porous ion-exchange resins may be of great relevance in order to overcome the diffusion limitations found with conventional beads, i.e. fibers − and (open-celled) monoliths. − A number of fibrous materials are available in the form of woven or nonwoven textiles, and some of them could be functionalized into ion-exchange fibers by grafting sulfonic or quaternary ammonium groups. With respect to powder and pellets, fibers have flexible structures and excellent mass transfer characteristics.…”

Section: Discussionmentioning

confidence: 99%

Ion Exchange Resins: Catalyst Recovery and Recycle

2008

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Section: Discussionmentioning

confidence: 99%

Ion Exchange Resins: Catalyst Recovery and Recycle

2008

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“…An excess of 1 N aqueous BaCl 2 was passed though a column packed with a weighed sample of the cation exchanger tested until the pH of both the eluent and eluate became equal [8]. Under these conditions, the initial sulfonic cation exchanger is converted to the Ba 2+ form.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, Structure, and Thermal Stability of a Sulfonic Cation Exchanger Grafted to Carbonized Fiber

et al. 2005

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A new kind of sulfonic cation exchanger based on carbonized fiber modified with poly(styrene3 divinylbenzene) was prepared by radiation grafting. The structural features and thermal stability of the cation exchangers prepared were studied.The reduction of toxicity of the automobile exhaust is a topical environmental problem. The solution of this problem includes the exclusion of tetraethyllead as an antiknock additive to gasoline. With this aim, benzine from catalytic craking and reforming is modified by adding high-octane oxygen-containing compounds: methyl tret-butyl ether (MTBE) and methyl tret-amyl ether (MTAE). In industrial production of these additives, granulated sulfonic cation exchangers Amberlyst 15, Dowex msm 31, KU-23, etc. are used as catalysts [133].It has been reported [4, 5] that FIBAN K-1 gel-like sulfonic cation exchanger based on polypropylene fiber [6] more effectively catalyzes MTBE and MTAE formation than KU-2 0 8 granulated gel-like and Dowex msm 31 macroporous sulfonic cation exchangers.In this context, it was of interest to develop a catalyst for preparing MTBE and MTAE based on carbonized fiber. Owing to several features (high porosity, small thickness, non swelling in polar solvents), carbonized fibers are more favorable for preparing grafted cation exchangers. In addition, these fibers exhibit a high electrical conductivity. Therefore, we can expect that sulfonic cation exchangers grafted to carbonized fiber will exhibit electrical conductivity irrespective of the moisture content. No data have been reported on sulfonic cation exchangers grafted to carbonized fibers. EXPERIMENTALIn our experiments, a nonwoven carbonized fabric Carbopon prepared by carbonization of viscose fiber was used as a fibrous base for a sulfonic cation exchanger.The main characteristics of Carbopon were as follows: fiber diameter 5310 mm, capillary moisture capacity 0.64 ml g !1 , average pore diameter d av 23 A, average surface area determined from low-temperature sorption of nitrogen 780 m 2 g !1 .In preparing sulfonic cation exchanger grafted to Carbopon, the following procedures were used. A weighed sample of air-dried Carbopon (5 g) was placed on the bottom of a 50-ml test tube and kept under vacuum (1 mm Hg) for 2 h at 90oC. Two identical Carbopon samples were used in parallel experiments. The test tubes containing Carbopon were cooled to room temperature, and a mixture of monomeric styrene and divinylbenzene (10 ml) in methanol (25 ml) was added. The styrene to divinylbenzene molar ratios in the reaction mixtures were 98 : 2 and 75 : 25, which corresponded to their relative content in gel-like (sample no. I) and maroporous (sample no. II) cation exchangers, respectively. The test tubes containing Carbopon and monomer mixture were closed, kept for 4h at 20oC and then placed in a channel of a RKhMgamma-20 cobalt (Co 60 ) unit for radiation grafting of styrene and divinylbenzene to Carbopon and their simultaneous copolymerization. In these experiments, the exposure time was 15 h, and the irradiation dose up...

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Organic Synthesis by Catalysis with Ion-Exchange Resins

Gelbard

2005

Ind. Eng. Chem. Res.

180

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This review is intended to give a wide scope on the uses of ion-exchange resins as catalysts or catalyst precursors in organic synthesis, for the preparation of fine or intermediate chemicals. Twelve families of reaction have been covered and presented according to the molecules to be synthesized, regardless of the anionic or cationic nature of the resins; thus, ∼300 references have been selected from January 1980. In acid-catalyzed reactions, the contribution of both Lewis acidity and Bro ¨nsted acidity are mentioned, and, when available, some aspects related to the stability or the recycling of the catalysts are reported. In base-catalyzed reactions, the importance of the thermal stability of anionic resins has been underlined. A table that is included as an appendix provides some data on the resins quoted here.

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Cited by 5 publications

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Ion Exchange Resins: Catalyst Recovery and Recycle

Ion Exchange Resins: Catalyst Recovery and Recycle

Synthesis, Structure, and Thermal Stability of a Sulfonic Cation Exchanger Grafted to Carbonized Fiber

Organic Synthesis by Catalysis with Ion-Exchange Resins

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