Reaction chromatography vinyl groups

Polyester composition can be determined by hydrolytic depolymerization followed by gas chromatography (28) to analyze for monomers, comonomers, oligomers, and other components including side-reaction products (ie, DEG, vinyl groups, aldehydes), plasticizers, and finishes. Mass spectroscopy and infrared spectroscopy can provide valuable composition information, including end group analysis (47,101,102). X-ray fluorescence is commonly used to determine metals content of polymers, from sources including catalysts, delusterants, or tracer materials added for fiber identification purposes (28,102,103). 

Table 97. Analysis of vinyl groups in polysiloxanes by alkali fusion reaction gas chromatography...

Besides simple alkyl-substituted sulfoxides, (a-chloroalkyl)sulfoxides have been used as reagents for diastereoselective addition reactions. Thus, a synthesis of enantiomerically pure 2-hydroxy carboxylates is based on the addition of (-)-l-[(l-chlorobutyl)sulfinyl]-4-methyl-benzene (10) to aldehydes433. The sulfoxide, optically pure with respect to the sulfoxide chirality but a mixture of diastereomers with respect to the a-sulfinyl carbon, can be readily deprotonated at — 55 °C. Subsequent addition to aldehydes afforded a mixture of the diastereomers 11A and 11B. Although the diastereoselectivity of the addition reaction is very low, the diastereomers are easily separated by flash chromatography. Thermal elimination of the sulfinyl group in refluxing xylene cleanly afforded the vinyl chlorides 12 A/12B in high chemical yield as a mixture of E- and Z-isomers. After ozonolysis in ethanol, followed by reductive workup, enantiomerically pure ethyl a-hydroxycarboxylates were obtained. 

The silyl-carborane hybrid diethynylbenzene-silylene polymer is prepared by a hydrosilylation reaction between diethynylbenzene-silylene polymer with the reactive vinyl side group and the 1,7-bis(dimethylsilyl)carborane group in toluene as solvent.The weight-average molecular weight of the polymer is determined to be 22,400 by using JASCO 802-SC gel permeation chromatography (GPC). The samples cured at 350 and 500° C are molded at 250°C for 6 min and pressed at 1795 kg/cm under vacuum for 30 s. 

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