Ion exchange resin Lewatit

The checkers used analytical grade AG 50W-X8 resin, which is a strongly acidic polystyrene gel type resin, supplied by Bio-Rad Laboratories. The submitters used the large-pore, strongly acidic ion-exchange resin Lewatit SPC 118, supplied by Bayer AG. 

Diethyl L-tartrate was usually purchased from Aldrich Chemical Co., Ltd., the diester was also prepared from L-tartaric acid by the procedure of Kocienski2 (triethyl orthoformate-ethanol-acetyl chloride) or Seebach3 [ethanol-acidic ion-exchange resin (Lewatit 3333)]. 

Labosowa L., Stofkova M., Kracunovska J. The study of possibilities of selective recovery of palladium(n) from chlorides solutions by ion exchange resin Lewatit TP-214. Acta Metallurgica Slovaca 2006 12 235-241. 

Validity heterogeneous catalyst (ion exchange resin Lewatit SBC 118 BG) low temperature (313K< T <353K)... 

We have recently developed a simple and specific method " for determination of thiocyanate, based on our finding that the ion-exchange resin Lewatit MPTO80 has a high affinity for thiocyanate. 

Cation-exchange resins are used as catalysts in the produdion of MTBE (methyl tertiary-butyl ether, 2-methoxy-2-methylpropane) and various other oxygenates and, lately, also in the dimerization of isobutene [30]. Other commercial applications of the cation-exchange resins indude dehydration of alcohols, alkylation of phenols, condensation readions, alkene hydration, purification of phenol, ester hydrolysis and other reactions [31]. The major producers of ion-exchange resins are Sybron Chemicals Incorporated [32] (Lewatit resins), Dow Chemical Company [33] (DOWEX resins), Purolite [28] (Purolite resins), and Rohm and Haas Company [27] (Amberlyst resins). 

Sydron Chemicals Inc., Chemical and Environmental Ion Exchange Products (Lewatit ion exchange resins product data sheet), http //www.ion-exchange.com/ service/ pdf chem. env.pdf, 20 August 2006. 

Lewatit SPS 118 is a strongly acidic ion exchange resin. - Yield over two steps, n. r. = not reported... 

Using a surface-sulfonated ion exchange resin (refs. 11-12), optimum accessibility of the active groups which are almost exclusively located at the inner surface of the microparticles is attained. The measured reaction rate (see Table 1) is about ten times higher than that of the identically cross-linked Lewatit SPC 11B. 

Ion-exchange polymeric resins are the most important types of exchangers currently in use [113-123], The first, totally organic ion-exchange resin was synthesized in 1935 by Adams and Holmer, when they produced a phenol-formaldehyde cation-exchange resin and an amine-formaldehyde anion-exchange resin, both obtained with the help of condensation polymerization reactions [113], In 1944, D Alelio synthesized styrene-based polymeric resins, which could be modified to obtain both cationic- and anionic-exchange resins. The majority of the resins commercially applied currently are of this type, for example, Amberlite IR-20, Lewatit S-100, Permutit Q, Duolite, C-20, Dowex-50, and Nalcite HCR. 

There are various ion-exchange resins [172,173] that can be used to remove ionic nickel and iron from brines. These include Duolite C-467, Lewatit TP-207, Purolite S-930, and Amberlite lRC-718. However, the pH of the brine must be less than about five to ensure that they are in an ionic form as Fe " " or Fe + and At higher pH,... 

Inglezakis et al. (2003) studied the removal of Pb2+ (500 ppm) in a batch system using the chelating resin Lewatit TP-207, under rigorous agitation (650 rpm) and ambient temperature (30 °C). The ion-exchange process is followed by an irreversible reaction in the resin phase, represented by the following scheme ... 

As common examples of monomers used for the production of resins, methacrylate and styrene can be mentioned, where the cross-linkers are ethylene dimethacrylate (EDMA) or divinyl benzene (DVB), respectively [205], The most important resins of this type are the poly(styrene-divinyl benzene) type or Amberlite resins, as well as the Wofatit and Lewatit [192] types. These materials have been widely applied as adsorbents [191,192,207] and as ion exchangers [193,194,208],... 

Styrene-DVB copolymer beads are sulfonated to produce the most widely used strong-acid type cation-exchange resins. To make them, the copolymer precursor beads are dispersed in about 10 times their weight of concentrated sulfuric acid and heated slowly to 150°C. The sulfonic acid group is normally introduced into the para position. Though the reaction is very simple in principle, it involves delicate operations and close control of parameters in order to achieve beads of suitable structure and durability. A fully mono-sulfonated, polystyrene has a theoretical ion content of 5.1 equivalents/kg (dry) but many commercial resins have about 4.4-S.2 eq/kg. Amberlite IR-120, Dowex-50, Nalcite HCR, Permutit Q, Duolite C-20 and C-25, and Lewatit S-100 are resins of this type. 

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