The polymerizations were conducted in toluene using manganese benziloxime complex and dibutylamine in a continuous flow of oxygen, and the structures, properties of the catalyst, and polymers were studied by nuclear magnetic resonance spectroscopy
(NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and gel ZIETDFMK permeation chromatography (GPC). The catalyst showed high regioselectivity and reasonably good yields to afford the poly(2,5-dimethyl-7,4-phenylene oxide)s with 1,4-C-O linkage structure which possessed melting point higher than the poly(p-phenylene sulfide) or type II liquid crystalline polymer. The regioselectivity was enhanced when employing molecular sieves-supported manganese catalyst system at selleck inhibitor 90 degrees C and the crystallinity of poly(2,5-dimethyl-1,4-phenylene oxide)s was estimated by wide-angle X-ray scattering (WARS) and DSC. The crystallinity was calculated about 23.7% and a heat-reversible melting and crystallization behavior occurred at 327.8 and 306.8 degrees C, respectively. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 1501-1507,2009″
“BACKGROUNDThe
effect of the B cation on the surface properties and catalytic activity in the dry reforming reaction over La0.4M0.6Al0.2Ni0.8O3 (M=noble metal) perovskite-type OSI744 oxides with surface area 3.26-4.14m(2) g(-1) and rhombohedral structure was studied.
RESULTSAmong LaAlxNi1-xO3 series, LaAl0.2Ni0.8O3 had the highest catalytic activity, but suffered a slow deactivation with time-on-stream (TOS). It is observed that all samples presented similar activity at low reaction temperatures (500-600 degrees C), while at higher temperatures (600-850 degrees C) the prepared solid was more active and perovskite phase was transformed into Ni-0 or La2O2CO3. It was found that among the noble metal samples, La0.4Rh0.6Al0.2Ni0.8O3
possessed the highest surface area and surface oxygen concentration and the best low-temperature reducibility. For the Rh catalyst the CH4 and CO2 conversions were 89.1 and 86.2%, which were the most resistant against coke deposition and showed very high stability without decrease in reforming and remained constant during the 3000 min TOS. The following order of activity was observed: La0.4Rh0.6Al0.2Ni0.8O3 > La0.4Ru0.6Al0.2Ni0.8O3 > LaAl0.2Ni0.8O3> La0.4Ir0.6Al0.2Ni0.8O3 La0.4Pt0.6Al0.2Ni0.8O3 > La0.4Pd0.6Al0.2Ni0.8O3.
CONCLUSIONSIt is believed that the high surface area and surface oxygen concentration and good low-temperature reducibility were responsible for the good catalytic performance of the La0.4Rh0.6Al0.2Ni0.8O3 sample.