Abstract
Introduction: Aromatic amines: aniline, p-toluidine or their alkyl analogs, are used as accelerators in radical polymerization reactions as well as in unsaturated polyester resin curing, initiated by peroxides. One on important accelerator is dipropoxy-p-toluidine. In the products by means of gas chromatography, detected of four components. This paper is intended to identify the composition of dipropoxy-p-toluidine.
Materials: The authors used a product with a purity of more than 96 %(m/m), and dichloromethane as a solvent.
Instrumentation: For analysis using a Bruker 436-GC gas chromatograph, coupled with a Bruker Scion SQ mass detector, injector, autosampler and two capillary chromatographic columns: wall-coated open tubular column (Bruker BR-5ms, 25 m x 0.25 mm, df = 0.25 µm), and Varian column packed with CP-Cyclodextrin-B-2,3,6-M-19 (25 m x 0.25 mm, df = 0.25 μm).
Results and Discussion: Dipropoxy-p-toluidine, obtained was analyzed using a GC-MS technique with two capillary columns with chiral packing and a standard non-polar phase. After a detailed analysis of mass spectra, it was found that the test product was a mixture of five isomers, including optically active ones.
Conclusions: Five out of the seven possible dipropoxy-p-toluidine isomers were found, including a pair of enantiomers. Three isomers (optically non-active) were assigned an explicit structure. A mechanism for propylene oxide addition to p-toluidine was proposed. Considering the proposed addition mechanism, the use of optically pure isomers of propylene oxide, does not lead to the obtaining of optically active products. The effect is independent of the configuration inversion during the synthesis.
Keywords: Alkoxylation, aromatic amines, di-propoxy-p-toluidine, mechanism of propylene oxide addition to p-toluidine, structure, unsaturated polyester resin curing.
Graphical Abstract
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