EFFECT OF STEREOCHEMISTRY IN ANIONIC POLYMERIZATION MODIFIERS

2017 ◽  
Vol 90 (2) ◽  
pp. 325-336
Author(s):  
Terrence E. Hogan ◽  
Waruna Kiridena ◽  
Laura Kocsis
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
1H Nmr ◽  
Column Chromatography ◽  
Anionic Polymerization ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry

ABSTRACT The influence of stereochemistry of polar modifiers on the microstructure of polybutadiene and poly(styrene-co-butadiene) was evaluated for 2,2′-ditetrahydrofurylpropane (DTHFP). The meso and d,l diastereomers were isolated from commercial 50/50 mixtures through column chromatography and characterized by 1H-NMR and gas chromatography/mass spectrometry. The meso-DTHFP was found to be more active than d,l-DTHFP in incorporation of vinyl during anionic polymerization. To form a polymer with approximately 55% vinyl, twice the amount of d,l-DTHFP was required compared with using pure meso-DTHFP. The mechanism for this effect will be discussed.

scholarly journals Investigation of the bioremediation potential of aerobic zymogenous microorganisms in soil for crude oil biodegradation

2011 ◽  
Vol 76 (3) ◽  
pp. 425-438 ◽  
Author(s):  
Tatjana Solevic ◽  
Milan Novakovic ◽  
Mila Ilic ◽  
Malisa Antic ◽  
Miroslav Vrvic ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Crude Oil ◽  
Laboratory Experiment ◽  
Column Chromatography ◽  
Control Sample ◽  
Gas Chromatography Mass Spectrometry ◽  
Methyl Groups ◽  
Chromatography Mass Spectrometry ◽  
Oil Biodegradation

The bioremediation potential of the aerobic zymogenous microorganisms in soil (Danube alluvium, Pancevo, Serbia) for crude oil biodegradation was investigated. A mixture of paraffinic types of oils was used as the substrate. The laboratory experiment of the simulated oil biodegradation lasted 15, 30, 45, 60 and 75 days. In parallel, an experiment with a control sample was conducted. Extracts were isolated from the samples with chloroform in a separation funnel. From these extracts, the hydrocarbons were isolated by column chromatography and analyzed by gas chromatography-mass spectrometry (GC-MS). n-Alkanes, isoprenoids, phenanthrene and its derivatives with one and two methyl groups were quantitatively analyzed. The ability and efficiency of zymogenous microorganisms in soil for crude oil bioremediation was assessed by comparison between the composition of samples which were exposed to the microorganisms and the control sample. The investigated microorganisms showed the highest bioremediation potential in the biodegradation of n-alkanes and isoprenoids. A considerably high bioremediation potential was confirmed in the biodegradation of phenanthrene and methyl phenanthrenes. Low bioremediation potential of these microorganisms was proven in the case of polycyclic alkanes of the sterane and triterpane types and dimethyl phenanthrenes.

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