Evaluation ethylene glycol production

An early source of glycols was from hydrogenation of sugars obtained from formaldehyde condensation (18,19). Selectivities to ethylene glycol were low with a number of other glycols and polyols produced. Biomass continues to be evaluated as a feedstock for glycol production (20). 

Laws have been enacted in many states in an attempt to prevent the sale and distribution of deleterious antifreeze products, such as salt solutions or petroleum coolants. Even ethylene glycol engine coolants must be evaluated by testing and comparison of test results with specifications for engine coolant concentrate, such as ASTM D 3306. These tests ensure desired levels of antifreeze coolant concentrate and inhibitor are available to adequately protect cooling systems against freezing, boilover and corrosion (Fig. 2). 

The Sharpless asymmetric dehydroxylation of resin-bound olefins was monitored using 3H, 13C and HMQC HRMAS NMR.63 The authors found 13C HRMAS NMR to be particularly suited to evaluating the progress of this reaction and permitted the enantiomeric excesses of the products to be determined before they were cleaved from the support. Most importantly, they were able to evaluate the types of substrates amenable to this reaction on solid supports, showing the ability of HRMAS NMR to contribute to synthetic questions. Transformation of the unnatural amino acid Lys(NH2) on a poly (ethylene glycol)-dimethylacrylamide (PEGA) resin to 6-hydroxynorleucine was confirmed by application of TOCSY HRMAS experiments.64... 

A further inference from the identical intramolecular isotope effects (kH/k2H = 10 1) observed with (S,S)- and (/ , /f)-[ 1,2-2 H 2 jethylene glycols (17 and 18) is that dioldehydratase does not exhibit stereospedficity for the enantiotopic methylene hydrogen atoms of the substrate. A similar conclusion could also be drawn from the product analysis of the reactions with (S)- and (/ )-[l-2H,]ethylene glycols, albeit the evaluation of the results was much more complicated [22],... 

In its discussion of human health effects, HC used data obtained in animal studies and uncertainty factors to calculate a tolerable dose over a lifetime of exposure. Short-term exposure was evaluated separately. As stated in its report, HC concluded that long-term or chronic exposure to ethylene glycol is not likely to present a human health problem, but that short-term (acute) exposures to indoor air concentrations from certain consumer products may exceed a tolerable concentration using necessary conservative assumptions. The language that HC used to explain its findings and conclusions are as follows ... 

Multifunctional Materials. Multifunctional property improvement by binding of specific polymers to fibers and fibrous products has been extensively investigated and reviewed (81). With poly(ethylene glycol) as the bound polymer, functional and aesthetic property improvements include thermal comfort, liquid absorbency/repellancy, increased wear life, soil release, resistance to static charge, antimicrobial activity, and resiliency. Numerous applications such as sportswear/ski wear, protective clothing for health care workers, durable and nondurable hygienic items, work uniforms, and space suits are being commercialized and evaluated. 

In the last forty years, the conjugation of methoxy-poly(ethylene glycol) (mPEG) has evolved to become a well-estabhshed technology for the improvement of the physicochemical and therapeutic properties of biopharmaceutical peptides and proteins (PEGylation). In fact, eleven PEGylated products are available nowadays in the marketplace, while several others are under clinical evaluation. 

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