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61.
Pyrolysis of tetrabromobisphenol-A containing paper laminated printed circuit boards 总被引:2,自引:0,他引:2
Tetrabromobisphenol-A (TBBA) is the most common brominated fire retardant. In this study, a TBBA containing paper laminated printed circuit board (PCB) prepared from novolac was pyrolysed by both TGA and in a quartz glass reactor between 40 and 1,000 degrees C. The products were online detected by MS. It was found that the PCB degraded in three steps. Step one (<270 degrees C) consisted of the evolution of water and CO(2) from the paper laminate. In the second step, between 270 and 370 degrees C, the fire retardant decomposed, releasing HBr and brominated aromatics. In the third step, at temperatures above 370 degrees C, the phenol resin decomposed and char was formed. Compared to pure TBBA, which mainly produces brominated phenols, the brominated products enclosed in the char released HBr during the last degradation step as well as during the second step. Most of the bromine left the resin in the form of HBr, with about 14% of the bromine being fixed in brominated aromatics and less than 2% remaining in the residue. 相似文献
62.
Due to the slow rate of incorporation of inert-metal ions into free-base porphyrins compared to other transition metals, several
methods have been proposed to accelerate the rate of metalation. However, these methods have disadvantages such as low yields,
difficulties of purification of final products, and environmental effects. To avoid those disadvantages, we reacted Pt(II)
and Pd(II) salts with H2(TPP), H2(TMPyP)4+, and their β-pyrrole derivatives, H2(Br8TPP) and H2(Br8TMPyP)4+, in 1-butyl-3-methylimidazolium bromide ([bmim]+Br−) under microwave irradiation. The combination of microwave heating and ionic liquids provides efficient thermal energy transfer
among the porphyrins and metal salts. In addition, ionic liquids stabilize charged species as well as their intermediates,
due to their high dipole moment and high boiling point. This not only shortens the reaction time but also gives high yields
of products at relatively low temperatures, of about 100°C compared to conventional synthesis methods: 150°C for DMF, 190°C
for DMSO. Here, we demonstrate that Pt(II)/Pt(II) metalloporphyrins are synthesized at high rates, e.g. 6–30 min for 100%
metalation, with high yields of 79–93% in [bmim]+Br− by microwave activation. 相似文献