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811.
S.A. Yashnik Z.R. Ismagilov V.V. Kuznetsov V.V. Ushakov V.A. Rogov I.A. Ovsyannikova 《Catalysis Today》2006,117(4):525-535
A synergetic effect in the catalytic activity has been found after palladium introduction in Mn–Al–O systems. The magnitude of the synergetic effect depends on the types of the oxidic manganese species: oxide Mn3O4, spinel (Mn, Mg)[Mn, Al]2O4 or hexaaluminate (Mn, Mg)LaAl11O19. The synergetic effect of Pd and manganese-containing compounds is observed only if palladium is introduced to the low-temperature precursor of the manganese alumina spinel or manganese hexaaluminate. The synergetic effect is not observed when high-temperature samples with formed spinel or hexaaluminate phases are modified with Pd. 相似文献
812.
813.
Polyfunctional monomers (PFMs), namely, trimethylol propane trimethacrylate (TMPTMA), trimethylol propane triacrylate, ethylene glycol dimethacrylate, and diethylene glycol diacrylate were blended with low‐density polyethylene (LDPE) and exposed to different doses of EB irradiation. Fourier transform infrared and ultraviolet and UV–vis spectroscopy of the unirradiated, irradiated, unloaded, and PFMs‐loaded LDPE films were studied under various irradiation doses up to 300 kGy. The degree of crosslinking and oxidative degradation, as measured by the spectroscopic parameters, were dependent on both the irradiation dose and the type of loaded PFMs. For all of the loaded monomers, the extent of crosslinking increased at different rates as a function of irradiation dose. TMPTMA monomer was the most efficient in enhancing the crosslinking of LDPE films compared to the other loaded monomers. However, the unloaded LDPE film showed the least extent of crosslinking. In addition, the EB‐radiation‐induced changes, such as trans‐vinylene formation, a decrease in vinyl and vinylidene unsaturation; and carbonyl double‐bond formation and change in crystallinity were correlated. The importance of these results on the prediction of the role of polyfunctional monomers in the production of crosslinked polymers is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2025–2035, 2003 相似文献
814.
815.
816.
817.
A novel process was developed for the bitumen emulsion upgrading, wherein emulsion breaking and upgrading occurred in the same reactor using H2 generated in situ from the water in the emulsion via the water gas shift reaction (WGSR). In this study, dibenzothiophene (DBT) was chosen as a model compound to investigate the effect of water and in situ H2 on hydrodesulfurization (HDS). All the experiments were performed in a 1-L autoclave reactor at temperatures between 300 and 380 °C using in situ H2 and ex situ H2 (externally supplied H2) over a dispersed Mo catalyst formed from phosphomolybdic acid (PMA). At very low water content, water was found to promote the HDS reaction in the ex situ H2 run probably because it facilitates the formation of more active dispersed MoSx species. At higher water content, however, water inhibits every individual reaction in the reaction network in the HDS of DBT, blocking the hydrogenation pathway more than the hydrogenolysis pathway. The relative reactivity of the in situ and ex situ H2 depends on the water content present in the reaction system. At an optimized mole ratio of H2O:CO (1.35), higher HDS activity was observed in the in situ H2 run compared to ex situ H2 run, and particularly, the hydrogenation pathway was promoted in the in situ H2 run. 相似文献
818.
Several fatty derivatives with bulky moieties were prepared by treatment of epoxidized isopropyl oleate with a number of alcohols
in the presence of sulfuric acid catalyst to provide a series of α-hydroxy ethers in good yield. The materials were analyzed
for cold flow performance through cloud point and pour point determinations. The most promising α-hydroxy ether produced in
this study, with respect to both low temperature behavior and economic criteria, was isopropyl 9(10)-(2-ethylhexoxy) 10(9)-hydroxystearate,
which has a cloud point of −23°C and pour point of −24°C. 相似文献
819.
Dielectric properties of KTaO3 ceramic fabricated by both conventional sintering and sintering followed by isostatic hot pressing (HIP) were measured at T =4.2 to 300 K over a frequency range from 400 Hz to 4 MHz. The weak field response shows a faint peak near 10 K which has a clear relaxation character, as in high-purity single crystals. The general response is well reproduced by the Barrett function, but additional polarizability with relaxation character is also in evidence at higher temperatures. No dielectric hysteresis was observed at high fields for cycling frequencies down to 0.04 Hz anywhere in the temperature range. 相似文献
820.
Efficacy of tertiary butylhydroquinone on the storage and heat stability of liquid canola shortening 总被引:1,自引:0,他引:1
Z. J. Hawrysh P. J. Shand C. Lin B. Tokarska R. T. Hardin 《Journal of the American Oil Chemists' Society》1990,67(9):585-590
The sensory (odor and flavor) and physicochemical characteristics of tertiary butylhydroquinone (TBHQ) treated and butylated
hydroxyanisole/toluene (BHA/BHT) treated liquid canola shortenings, subjected to accelerated storage (Schaal oven test at
65°C) and deep fat heating (at 185°C), were determined. Data for the Schaal oven test indicate that TBHQ was effective in
retarding oxidative rancidity in liquid canola shortenings. However, addition of the commonly used mixture of BHA/BHT to canola
shortenings resulted in only a slight decrease in oxidation during schaal oven storage. The results obtained from deep fat
heating of canola liquid shortening show that neither TBHQ nor BHA/BHT was effective in enhancing oxidative and thermal stability
of this product. 相似文献