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1.
Theoretical investigation of solvent effects on the selective hydrogenation of furfural over Pt(111)
Jian Wang Cun-Qin Lv Jian-Hong Liu Rong-Rong Ren Gui-Chang Wang 《International Journal of Hydrogen Energy》2021,46(2):1592-1604
It was well known that solvent effect plays a very important role in the catalytic reaction. There are many theoretical studies on the solvent effect in homogeneous catalysis while there are few theoretical studies on the solvent effect in the heterogeneous catalytic reaction and there has been no work to investigate the solvent effect on furfural transformation in heterogeneous catalysis. In the present work, both the density functional calculations and the microkinetic analysis were performed to study the selective hydrogenation of furfural over Pt(111) in the presence of methanol as well as toluene and compared with that in the gas condition. The present results indicated that the methanol can enhance the adsorption strength of furfural and other oxygen-containing reaction species due to its relatively strong polarity properties and this can be a main reason for solvent-induced high activity and selectivity. Another reason is that reaction paths study showed that the presence of methanol solvent makes the dehydrogenation of furfural less thermochemical due to the fact that furfural is more stabilized than that of dehydrogenation species, and methanol also has an inhibition effect on the dehydrogenation of furfural in the kinetic aspect, and further energetic span theory proves highest activity and selectivity for hydrogenation in methanol solvent of vapor, methanol and toluene. Moreover, microkinetic model simulation demonstrated that the activity and selectivity of hydrogenation in methanol is both higher than that in vapor and toluene. The much higher activity in methanol is due to the stabilized adsorbed reactants in the surface, which leads to a higher surface coverage of furfural. It might be proposed based on the present work that a solvent with relatively strong polarity may be favorable for the high selective hydrogenation of furfural. 相似文献
2.
Indium separation using ion exchange resins from acidic polymetallic and very diluted solutions are investigated. Since the selectivity of commercial ion exchange resins have proven to be too low for an effective separation from solutions with high content of other metals, Lewatit® TP 208 was impregnated with common extractants to enhance its properties. By resin impregnation with D2EHPA and Cyanex 272, not only the selective indium recovery was reached but also the resin capacity was increased approx. two times. The best loading and elution performance were shown by Cyanex 272-impregnated Lewatit® TP 208, increasing the indium purity in the eluate from 0.75 % to 85 %. 相似文献
3.
Kwang-Hee Lim 《Korean Journal of Chemical Engineering》2005,22(2):228-233
An experiment for five stages of a biofilter-run was performed to investigate the effect of hydrophilic ethanol and hydrophobic
toluene on the biodegradation of hydrophobic toluene and hydrophilic ethanol, respectively, when waste-air containing toluene
and ethanol was treated by a biofilter. Removal efficiencies of toluene and ethanol began to decrease when inlet load surpassed
90 g/m3/h and 100 g/m3/h consistent with maximum elimination capacities of toluene and ethanol, respectively. At the end of the biofilter-run, removal
efficiencies for toluene and ethanol were decreased and maintained at 65% and 40%, respectively. The concentration of toluene
at 1st sampling port was raised by factor of two in the 3rd stage of the biofilter run when the inlet load of ethanol co-feed
was increased by 1.5 times, while the process conditions of toluene were maintained the same as those of the 2nd stage of
biofilter-run. According to the result of Mohseni and Allen, it may be interpreted that removal efficiency of hydrophobic
toluene was affected by the presence of hydrophilic ethanol when high load of hydrophobic toluene was applied like that of
the 1st sampling port of the biofilter. However it was not the case when a low load of hydrophobic toluene was applied like
those of the 2nd, 3rd and 4th sampling ports since hydrophobicity of toluene is much less that of α-pinene. Thus, it may be
suggested that biodegradation of hydrophobic VOC was interfered by hydrophilic VOC dissolved in the biolayer and the degree
of interference was proportional to the inlet load of hydrophobic VOC as well as that of hydrophilic VOC and was inversely
proportional to the solubility of hydrophobic VOC. However, it was inferred that the existence of hydrophobic toluene from
waste-air can hardly inversely hinder the removal of hydrophilic ethanol in the biofilter when timeevolutions of hydrophilic
ethanol concentrations of this experiment were compared with those of the previous experiment of biofilter to treat waste-air
containing ethanol only. 相似文献
4.
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6.
Daniel WinnMichael F. Doherty 《Chemical engineering science》2002,57(10):1805-1813
A method for predicting the shape of organic crystals grown from polar solvents is presented. The model is an improvement of the recent method developed by Winn and Doherty (A.I.Ch.E. Journal 44 (1998) 2501) for predicting the shape of organic crystals grown from solvents in which the energy of adhesion at the interfaces is dominated by dispersive forces (e.g., non-polar solvents). The principal characteristic of the new method is that it can account for the role of hydrogen donor and hydrogen acceptor atoms in forming strong bonds at the interface. This technique is a first step towards predicting the shapes of organic crystals grown from polar solvents, and has been applied successfully to predict the shape of adipic acid grown from water, and succinic acid grown from water and from propanol. 相似文献
7.
8.
Alumina coatings have been deposited by combustion flame pyrolysis on amorphous silica and stainless steel substrates with the objective to study the effect of solvent composition, Fe3+ addition and determine the thermal fatigue lifetime. The effect of solvent composition on crystallinity, transformation temperature and hardness are studied, three different solvent compositions are chosen for preparing the aluminium nitrate solution. Using 100% water, as-deposited films are amorphous and transform to α-alumina only upon annealing, while this equilibrium phase is directly obtained but with a porous microstructure by using 100% methanol. The hardness of the coatings varies with the flammability of the solvents. The effect of Fe3+ addition on the crystallization of alumina is studied by combustion pyrolysis of aqueous solutions of Al3+ and Fe3+ nitrates. Small amount of ferric nitrate reduced the transformation temperature by 100 °C. Thermal cycling of as-deposited amorphous alumina on stainless steel substrate is carried out at different temperatures to determine the thermal fatigue lifetime. 相似文献
9.
In this study, crisp and fuzzy multiple-goal optimization approaches are respectively introduced to design an optimal biocompatible solvent to a two-stage extractive fermentation with cell recycling for ethanol production. When designing a biocompatible solvent for the extractive fermentation process, many issues, such as extractive efficiency, conversion, amount of solvent utilized and so on, have to be considered. An interactive multiple-goal design procedure is introduced to determine a trade-off result in order to satisfy such contradicted goals. Both approaches could be iterated to solve the interactive multiple-goal design problem in order to yield a trade-off result. However, the crisp optimization design is a tedious task that requires the designer to provide various pairs of the upper bounds for the design problem to obtain the corresponding solution. The fuzzy optimization approach is able to be trade-off several goals simultaneously and to yield the overall satisfactory grade for the product/process design problem. 相似文献
10.
Extraction behavior of N, N'-didecanoylpiperazine (DDPEZ) for U(Ⅵ)in a series of solvents from aqueous nitric acid media was investigated for the first time.The dependence of distribution ratios on the concentration of aqueous nitric acid.extractant and temperature has been discussed. The increasing sequence of extractiveability of DDPEZ is given: chloroform, carbon tetrachloride, dimethylbenzene, toluene,benzene.`` 相似文献