Nonionic resins

More recent approaches have used resin extractions, initially the nonionic resin XAD2 and XAD7. These resins are effective where the pH was kept at 10 while mixing the plasma and resin. The supernatant is discarded and the bile... 

The results of model compound recovery experiments, in part, support these selection criteria. For example, the anionic resin (MP-1) yielded the best recoveries of the anionic organics (little or no adsorption was observed on subsequent resins) glycine was equally distributed (but poorly recovered) on MP-1 and MP-50 (no adsorption was observed on the nonionic resins). Although some selective adsorption occurred on the lower surface area ionic resins, the nonpolar macro-porous XAD-2 showed its retentive power for low-polarity compounds as none were seen to break through to the more polar methacrylate polymer, XAD-7. XAD-7 was included in the system for use with reclaimed and surface waters (21) because literature reports indicated that the methacrylate XAD resins had significantly better retention of humics, fulvics, and smaller phenolics (9, 29, 30). However, in the... 

A wide variety of solvents have been utilized for the extractions. Other procedures have been used, particularly with urine in drug screening programs. Included are drug adsorption on cation-exchange resin paper, XAD-2 nonionic resin, and charcoal. 

Other potential DOP isolation methods are based on sorption using anion-exchange resins or nonionic resins. Extensive research in concentrating humic material has employed these methods (55). For isolation and concentration of DOP, these techniques have several disadvantages, such as possible irreversible sorption onto the resins and the concentration of all anionic species present in the sample. Another major drawback is the need to use a strong base to remove the sorbed material from the resin. For sorption to occur with nonionic resins requires the protonation of all weak acids, thus exposing the sample to low pH. 

Two major strategies can be used for the recovery and purification of CPC. One strategy involves the use of activated carbon or the use of a nonionic resin. Because of the high selectivity of the resin, CPC is preferentially adsorbed over penicillin N or the contaminating biosynthetic precursor molecules. Most of the penicillin N is removed in the pH 2.0 acidification step. An additional anion- and cation-exchange step usually results in high-quality CPC. A large fraction of the CPC is converted to 7-ACA and derivatized to semisynthetic cephalosporins. 

A critical review is presented of the methods commonly used to isolate and concentrate aquatic humic substances, important steps in any extraction scheme are filtration, concentration, isolation, and preservation. Various filtration options are outlined and compared filtration is important for obtaining low-ash humic substances. Advantages and disadvantages of commonly used concentration and isolation techniques are discussed, and sorption on the synthetic macroporous resins XAD-8, a nonionic resin, and Duolite A-7, a weak anion-exchange resin, are recommended as the most efficient methods. Two established extraction schemes utilizing these resins are discussed. 

A fluorimetric FIA system based on the fluorescence enhanced effect of cyanide on the copper- bis[N,N-bis-(carboxymethyl)aminomethyl]fluorescein (calcein) complex has been used for cyanide determination [34]. Also, a flow-through sensing approach was developed based on the immobilization of the calcein on a nonionic resin. Both systems are based on the interaction between the nonfluorescent copper-calcein complex and cyanide. Interaction of cyanide with the Cu(II) ions boimd to calcein resulted in the restoration of the calcein fluorescence. Linear dynamic range from the quantification limit is up to 0.4 mM CN , detection limit 4 x 10 mM CN, relative standard deviation 1.2%, and sampling frequency is 30 Hz h in the FIA system. For the flow-through approach, the linear dynamic range from the quantification limit was up to 0.2 mM CN, the detection limit 5 X 10 mM CN, the relative standard deviation 3.7%, and the sampling frequency is 10 Hz hr ... 

Wyatt W.A., Poirier G.E., Bright F.V. and Hieftje G.M. (1987) Fluorescence spectra and lifetimes of several fluorophores immobilized on nonionic resins for use in fiberoptic sensors. Anal. Chem., 59, 572-576. 

The production of alkylphenols exceeds 450,000 t/yr on a worldwide basis. Alkylphenols of greatest commercial importance have alkyl groups ranging in size from one to twelve carbons. The direct use of alkylphenols is limited to a few minor appUcations such as epoxy-curing catalysts and biocides. The vast majority of alkylphenols are used to synthesize derivatives which have appUcations ranging from surfactants to pharmaceuticals. The four principal markets are nonionic surfactants, phenoUc resins, polymer additives, and agrochemicals. 

Nonionic surfactants and phenoUc resins based on alkylphenols are mature markets and only moderate growth in these derivatives is expected. Concerns over the biodegradabiUty and toxicity of these alkylphenol derivatives to aquatic species may limit their use in the future. The use of alkylphenols in the production of both polymer additives and monomers for engineering plastics is expected to show above average growth as plastics continue to replace traditional building materials. 

Latex Compounding. Latex compounding must take into account the stability of the latex both before and after compounding. Where consideration of soHds concentration permits, the additives are best predispersed in a compatible aqueous surfactant before addition to the latex. The volume of additives, especially if clay fillers are involved, may easily be enough to starve the system for soaps and flocculate the compound. On the other hand, dry powders or molten resins may often be added directly to the nonionic latex. 

For some nonionic, nonpolar polymers, such as polyethylene glycols, normal chromatograms can be obtained by using distilled water. Some more polar nonionic polymers exhibit abnormal peak shapes or minor peaks near the void volume when eluted with distilled water due to ionic interactions between the sample and the charged groups on the resin surface. To eliminate ionic interactions, a neutral salt, such as sodium nitrate or sodium sulfate, is added to the aqueous eluent. Generally, a salt concentration of 0.1-0.5 M is sufficient to overcome undesired ionic interactions. 

The GBR resin works well for nonionic and certain ionic polymers such as various native and derivatized starches, including sodium carboxymethylcel-lulose, methylcellulose, dextrans, carrageenans, hydroxypropyl methylcellu-lose, cellulose sulfate, and pullulans. GBR columns can be used in virtually any solvent or mixture of solvents from hexane to 1 M NaOH as long as they are miscible. Using sulfonated PDVB gels, mixtures of methanol and 0.1 M Na acetate will run many polar ionic-type polymers such as poly-2-acrylamido-2-methyl-l-propanesulfonic acid, polystyrene sulfonic acids, and poly aniline/ polystyrene sulfonic acid. Sulfonated columns can also be used with water glacial acetic acid mixtures, typically 90/10 (v/v). Polyacrylic acids run well on sulfonated gels in 0.2 M NaAc, pH 7.75. 

Phenol can be alkylated to alkylphenols. These compounds are widely used as nonionic surfactants, antioxidants, and monomers in resin polymer applications ... 

Surfactants used as lubricants are added to polymer resins to improve the flow characteristics of the plastic during processing they also stabilise the cells of polyurethane foams during the foaming process. Surfactants are either nonionic (e.g. fatty amides and alcohols), cationic, anionic (dominating class e.g. alkylbenzene sulfonates), zwitterionic, hetero-element or polymeric (e.g. EO-PO block copolymers). Fluorinated anionic surfactants or super surfactants enable a variety of surfaces normally regarded as difficult to wet. These include PE and PP any product required to wet the surface of these polymers will benefit from inclusion of fluorosurfactants. Surfactants are frequently multicomponent formulations, based on petro- or oleochemicals. 

Assuming that the hydrophobic and nonionic nature of the polystyrene matrix prevented infiltration by solvent, an alternative synthesis was devised starting with macroporous 3% cross-linked polystyrene. This resin was first washed (28 ) with ... 

We have developed and tested a metabolism system and regimen which allows collection of data comparable to those from terrestrial animals. The key to our experiments is a metabolism chamber, described previously Cl3, 14) CFig. 1), which can be operated in either the static or flow-through mode. Briefly, individuals or groups of animals are held at constant temperature in the jacketed glass chamber (A), on a stainless steel screen (B), while pure water or test solution is passed over them (or held under static conditions). Solid wastes are separated in a jacketed container (C) held near 0°C to minimize microbial action, and the effluent containing dissolved metabolites is passed onto a column of nonionic macroreticular adsoprtion resin where organic solutes are adsorbed from solution (D). 

Uses. Polyester resins use up about 60% of the propylene glycol (and most of the dipropylene glycol) manufactured. The remainder is used as a tobacco and cosmetic humectant. (a chemical that keeps moisture around), automotive antifreeze and brake fluid ingredients, food additive, and plasticizers for various resins, and making nonionic detergents and coatings. Propylene glycol is an excellent solvent. 

Only 10% of the dissolved organic carbon in seawater has been characterized on a molecular level. About 5 to 23% of this DOC can be isolated from seawater by adsorption onto a nonionic macroporous resin fiallowed by elution with an alkaline solution. 

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