Microwave Assisted Solvent Extraction of Poly Vinyl Chloride for Analysis of Plasticizers by Gas Chromatography (GC/FID)

Analysis of plasticizers in poly vinyl chloride (PVC) is critical to ensuring that finished products have the specified performance characteristics. The analytical process requires solvent extraction of the sample followed by gravimetric and/or GC/FID analysis. The traditional Soxhlet apparatus used for sample preparation is time consuming, uses large volumes of solvent, and is costly. Microwave Assisted Solvent Extraction (MASE) utilizes small solvent volumes and control of extraction solvent temperatures above normal atmospheric boiling points, dramatically shortening the time and cost required to extract plasticizers from PVC.     

Chromatographic resolution of the enantiomers of a pharmaceutical intermediate from the milligram to the kilogram scale.

The preparative chromatographic resolution of racemic mixtures is rapidly becoming a standard approach for the generation of enantiomers in pharmaceutical R&D. This paper will discuss the optical resolution of a pharmaceutical intermediate as the separation is scaled up from the milligram to the kilogram scale. Difficulties encountered and their solutions at each scale will be discussed. In addition, the exploration of Simulated Moving Bed (SMB) for the separation will also be discussed. Finally, a comparison of the productivities and solvent consumption for each method and scale will be presented.     

Biotechnology and polymer chemistry: a growing relationship

DuPont is using biotechnology to make chemical compounds and materials, especially polymers and polymer intermediates ‐ demonstrating that biotechnology can lead to more effective and productive manufacturing processes for traditional chemical businesses as well as pharmaceuticals, agricultural products, and new products for improved nutrition and health.     

Polymers from aryl cyclic sulfonium zwitterions—photosensitive materials cast from and developed in water

Upon photolysis or heating, aryl cyclic sulfonium (ACS) zwitterions polymerize by ring‐opening and loss of charge to yield nonionic polymers. These water‐soluble monomers potentially are useful for photolithography because they can be cast from and developed in water. The ACS zwitterion from bisphenol A, 1,1′‐[isopropylidenebis(6‐hydroxy‐3,1‐phenylene)] bis (tetrahydrothiophenium hydroxide) bis(inner salt) (1) is a negative‐tone, photosensitive material that after photolysis yields a crosslinked film. Unexposed regions are removed by water. The cured film has a low dielectric constant, high volume resistivity, a high degree of planarization, low residual stress, thermogravimetric stability, acceptable fracture toughness, and high hardness. These are desirable properties for a dielectric material used in microelectronic applications. However, a shortcoming of the material is its low T_g, at about 140 °C. A second ACS zwitterion, 1,1′‐[fluorenylidenebis(6‐hydroxy‐3,1‐phenylene)] bis(tetrahydrothiophenium hydroxide) bis(inner salt) (2) was prepared that yields a crosslinked polymer with a higher T_g of about 190 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1283–1290, 2000