Scavenging agent

The so-called antiplasticizers are used in PET bottle manufacturing to enhance the gas barrier. The proposed additives comprise aromatic hydroxy and carboxylic group containing benzene and naphthalene compounds, for example, methyl-4-hydroxybenzoate or 

Acid scavengers or antacids are often used in base stabilization packages of polyoleflns to neutralize acidic 

The main application fields of aldehyde scavengers are PET (more specifically wafer bottles made from PET), and polyacetals such as POM or polymers synthesized from formaldehyde such as urea-formaldehyde resins. 

Fluoropolymers (e.g., copolymers of vinylidene fluoride and hexafluoropropylene) and silicone-based (e.g., poly-dimethylsiloxanes) additives are often referred to as processing aids, preventing melt-fracture, for example, the so-called sharkskin. Fluoropolymers are applied in concentrations between 0.01% and 0.1%. 

Thermal degradation of polyoxymethylene and polyacetals results in the formation of formaldehyde, which is furthermore catalyzed by oxidation of formaldehyde to formic acid. In addition to antioxidants and acid scavengers, formaldehyde scavengers are used in polyacetal formulations. Formaldehyde scavengers of choice are nitrogen compounds, for example, melamine derivatives such as benzoguanamine, urea derivatives such as allantoin, hydrazides, imides, and polyamide. 

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Pd(Ph3P)4, LiBH4, THF, 88% yield. NaBH4 can also be used as an allyl scavenging agent. ... 

Brezonik PL, J Fulkerson-Brekken (1998) Nitrate-induced photoysis in natural waters controls on concentrations of hydroxyl radical photo-intermediates by natural scavenging agents. Environ Sci Technol 32 3004-3010. 

Nirankari, V.S., Varma, S.D., Lakhanpal, V. and Richards, R.D. (1981). Superoxide radical scavenging agents in the treatment of alkali burns an experimental study. Arch. Ophthalmol. 99, 886-893. 

Klein, S.M., Cohen, G., Lieber, C.S. and Cederbaum, A.l. (1983). Increased microsomal oxidation of hydroxyl scavenging agents and ethanol after chronic consumption of ethanol. Arch. Biochem. Biophys. 223, 425-432. 

A comprehensive list of the most common appHcations of supported scavenger agents can be found in several reviews [49]. 

Finally, highly reactive salts such as triphenylmethyl hexachloroantimonate provide very convenient scavenging agents for the removal of the last traces of nucleophilic impurities in polymerisation solvents. Penczek (35) has taken this further in developing a spectroscopic technique for the determination of trace quantities of residual water by reaction of the latter with known concentrations of triphenylmethyl salts, according to the following equilibria ... 

Blasi et al. (2008) developed an experimental method for removing carbonyl compounds from wine. It used selective liquid-solid extraction, with phenylsulfonylhydrazine as a scavenging agent, bonded to a porous polymer support. The method was efficient for reducing the SO2 binding power of botrytized wines, without impairing their sensory qualities. 

Use of a readily separable, polymer-supported reagent to facilitate a chemical transformation is not always a panacea. Yields should preferably be high, and the recovery and purification of the desired product from the reaction mixture should be practical. Polymer-supported scavenging agents to scavenge byproducts have been employed, as also have polymer-supported reagents that capture the desired product from a reaction mixture.64... 

Many free-radical scavengers (including dithiols and dithiocarbamates) have potential therapeutic usefulness as radioprotective agents. Copper complexes are known to be scavenging agents for the superoxide radical, which is believed to play a role in the induction of radiation damage. The toxic effects of superoxide are believed to lie in its ability to reduce metal ions, for example Cu(II) to Cu(I),... 

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