Polyethylene glycol applications

Corrective Action Application At a Navy facility in Guam, approximately 25 tons of PCB contaminated soil was treated using the KPEG (potassium polyethylene glycol) process. PCB concentrations were reduced from 3000 ppm to less than 5 ppm. Upon completion of treatment using the KPEG process, the soil was neutralized from a pH of 14 to 7. A full-scale system for this process is currently under development. 

With the discovery of the crowns and related species, it was inevitable that a search would begin for simpler and simpler relatives which might be useful in similar applications. Perhaps these compounds would be easier and more economical to prepare and ultimately, of course, better in one respect or another than the molecules which inspired the research. In particular, the collateral developments of crown ether chemistry and phase transfer catalysis fostered an interest in utilizing the readily available polyethylene glycol mono- or dimethyl ethers as catalysts for such reactions. Although there is considerable literature in this area, much of it relates to the use of simple polyethylene glycols in phase transfer processes. Since our main concern in this monograph is with novel structures, we will discuss these simple examples further only briefly, below. 

It was noted early by Smid and his coworkers that open-chained polyethylene glycol type compounds bind alkali metals much as the crowns do, but with considerably lower binding constants. This suggested that such materials could be substituted for crown ethers in phase transfer catalytic reactions where a larger amount of the more economical material could effect the transformation just as effectively as more expensive cyclic ethers. Knbchel and coworkers demonstrated the application of open-chained crown ether equivalents in 1975 . Recently, a number of applications have been published in which simple polyethylene glycols are substituted for crowns . These include nucleophilic substitution reactions, as well as solubilization of arenediazonium cations . Glymes have also been bound into polymer backbones for use as catalysts " " . 

Many procedures have been suggested to achieve efficient cofactor recycling, including enzymatic and non-enzymatic methods. However, the practical problems associated with the commercial application of coenzyme dependent biocatalysts have not yet been generally solved. Figure A8.18 illustrates the continuous production of L-amino adds in a multi-enzyme-membrane-reactor, where the enzymes together with NAD covalently bound to water soluble polyethylene glycol 20,000 (PEG-20,000-NAD) are retained by means of an ultrafiltration membrane. 

Based on this analysis it is evident that materials which are biaxially oriented will have good puncture resistance. Highly polar polymers would be resistant to puncture failure because of their tendency to increase in strength when stretched. The addition of randomly dispersed fibrous filler will also add resistance to puncture loads. From some examples such as oriented polyethylene glycol terephthalate (Mylar), vulcanized fiber, and oriented nylon, it is evident that these materials meet one or more of the conditions reviewed. Products and plastics that meet with puncture loading conditions in applications can be reinforced against this type of stress by use of a surface layer of plastic with good puncture resistance. Resistance of the surface layer to puncture will protect the product from puncture loads. An example of this type of application is the addition of an oriented PS layer to foam cups to improve their performance. 

The most effective lubricants are the hydrophobic stearates, such as magnesium stearate, calcium stearate, and stearic acid. Magnesium stearate is the most widely used lubricant [117,118]. Lubricants proposed as being less hydrophobic such as hydrogenated vegetable oils, polyethylene glycols, and sodium stearyl fumarate are less effective in this application [118]. 

Kamimura M, Miyamoto D, Saito Y, Soga K, Nagasaki Y (2008) Design of polyethylene glycol)/streptavidin co-immobilized upconversion nanophosphors and their application to fluorescence biolabeling. Langmuir 24 8864-8870... 

Inada, Y., Takahashi, K., Yoshimoto, T., Ajima, A., Matsushima, A., and Saito, Y. (1986) Applications of polyethylene glycol-modified enzymes in biotechnological processes Organic solvent-soluble enzymes. Trends Biotechnol. 4, 190-194. 

Graham, N. B., Polyethylene glycol) Gels and Drug Delivery, in Poly(Ethylene Glycol) Chemistry Biotechnical and Biomedical Applications (J. M. Harris, Ed.), pp. 263-281. Plenum Press, New York (1992). 

Bioerodible polymers offer a unique combination of properties that can be tailored to suit nearly any controlled drug delivery application. By far the most common bioerodible polymers employed for biomedical applications are polyesters and polyethers (e.g., polyethylene glycol), polylactide, polyglycolide and their copolymers). These polymers are biocompatible, have good mechanical properties, and have been used in... 

S Zalpsky, JL Chang, F Albericio, G Barany. Preparation and applications of polyethylene glycol-polystyrene graft resin supports for solid-phase peptide synthesis. Reactive Polymers 22, 243, 1994. 

It was a result of demand from industry in the mid-1960s for an alternative to be found for the expensive traditional synthetic procedures that led to the evolution of phase-transfer catalysis in which hydrophilic anions could be transferred into an organic medium. Several phase-transfer catalysts are available quaternary ammonium, phosphonium and arsonium salts, crown ethers, cryptands and polyethylene glycols. Of these, the quaternary ammonium salts are the most versatile and, compared with the crown ethers, which have many applications, they have the advantage of being relatively cheap, stable and non-toxic [1, 2]. Additionally, comparisons of the efficiencies of the various catalysts have shown that the ammonium salts are superior to the crown ethers and polyethylene glycols and comparable with the cryptands [e.g. 3, 4], which have fewer proven applications and require higher... 

Polyethylene glycols (PEG) have been employed as phase transfer agents (and as solvents) in a number of reactions(11). Application of PEG-400 to the Wacker reaction results in the oxidation of both terminal and internal olefins (e.g., isomeric butenes to butanone) (12). 

The application of thermomorphic solvent systems as a new recycUng concept was investigated in various C - C bond-forming reactions. Therefore methods for a systematic choice of solvent combinations were developed. In addition to common organic solvents more unusual solvents Hke cycHc carbonates, pyrroUdones, polyethylene glycols and lactones were used in the investigations. The phase behaviour of the new solvent systems was determined by cloud titrations. From these experiments information about the temperature dependency and an appropriate composition for the reactions could be obtained. The results were used in the development of an expert system for the solvent selection. 

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