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Alkaline wet oxidation of lignin was performed to study the effect of Cu-Mn mixed oxide catalysts on the production of vanillin at between 120–180 °C using H2O2 as an oxidizing agent. The mixed oxide catalysts were prepared by a sol-gel method with mixing ratios of Cu to Mn between 0.25 and 0.75 and characterized by XRD, XPS, N2-physisorption, SEM-EDS, and H2-TPR. The XRD and N2-physisorption analyses showed a non-stoichiometric spinel structure (Cu1.5Mn1.5O4) and a relatively high BET surface area of the mixed oxides compared with pure Cu and Mn oxides, respectively. In addition, the Cu-Mn mixed oxide catalysts exhibited better redox properties and a higher catalytic performance for lignin oxidation to vanillin and other aromatic oxygenates. Higher Cu contents in the mixed oxide catalysts promoted the over-oxidation of vanillin producing vanillic acid along with the formation of more surface oxygen species on the catalyst surface. Finally, a possible reaction pathway for the catalytic conversion of lignin to vanillin was proposed.

With concerns over global warming and climate change, many efforts have been devoted to mitigate atmospheric CO

Bio-jet fuel range alkanes were prepared by catalytic deoxygenation reaction of non-edible acid oils with no added hydrogen. A WOx[6]/Pt[1.6]/TiO2 was used for the deoxygenation of stearic acid and Jatropha fatty acid derived from Jatropha oil by hydrolysis. Tungsten addition to the Pt/TiO2 showed remarkably enhanced performance, a degree of deoxygenation of 86%, which is more than two times higher than that of the Pt/TiO2, even though the WOx/TiO2 had almost no activity for deoxygenation reaction. The enhanced Pt-related hydrogen uptake, measured by H2-TPR, and XPS analysis showed the intimate contact of tungsten with Pt nanoparticles supported on TiO2. This tight contact allows for easier C C cleavage over Pt nanoparticles and this is assisted by the strong bonding between tungsten and oxygen in the reactant, resulting in more C17 hydrocarbon production on the WOx/Pt/TiO2.

Endo-1,4-β-xylanase is one of the most important enzymes employed in biorefineries for obtaining fermentable sugars from hemicellulosic components. Herein, we aimed to improve the catalytic performance of Bacillus circulans xylanase (Bcx) using a structure-guided rational design. A systematic analysis of flexible motions revealed that the R49 component of Bcx (i) constrains the global conformational changes essential for substrate binding and (ii) is involved in modulating flexible motion. Site-saturated mutagenesis of the R49 residue led to the engineering of the active mutants with the trade-off between flexibility and rigidity. The most active mutant R49N improved the catalytic performance, including its catalytic efficiency (7.51-fold), conformational stability (0.7 °C improvement), and production of xylose oligomers (2.18-fold higher xylobiose and 1.72-fold higher xylotriose). The results discussed herein can be applied to enhance the catalytic performance of industrially important enzymes by controlling flexibility.

The catalytic deoxygenation reaction of crude Jatropha oil (CJO) was carried out to produce oxy-free hydrocarbons in assistance with hydrogen in-situ produced from formic acid solution (30%) and addition effect of formic acid was discussed on the deoxygenation reaction and product distribution. Mixing of formic acid with reactant yielded higher oil conversion and higher selectivity to normal hydrocarbon (mainly C 15 and C 17 ) than those of the other cases (no mixing or water addition). Total surface area and total pore volume of used catalysts in the batch reactor followed the order Pd/C–formic acid solution > Pd/C–water > Pd/C–no co-reactant under constant conditions. Moreover, significantly higher degree of deoxygenation with a high initial resistance to catalyst deactivation was observed on Pd/C catalyst in the presence of formic acid during the continuous catalytic reaction. This means that addition of formic acid solution as the hydrogen donor is favorable the deoxygenation reaction and the initial deactivation of catalyst. As results of continuous deoxygenation reaction using the mixture of oil and formic acid, normal hydrocarbon in the liquid product was main product, about 97%, and the degree of deoxygenation was about 99.5%.

The catalytic conversion of non-edible oil was carried out over a Pd-based zeolite catalyst in a single-step process (SSP) with no added hydrogen to examine the possibility of the direct production of hydrocarbons in the ranges of jet fuel. The conversion of stearic acid, a model fatty acid compound, reached 100% and the proportion of hydrocarbons in the jet-fuel range was 69.3% over a Pd/beta-zeolite catalyst at 270 °C in a SSP. In addition, the obtained jet-fuel was composed of normal, isomer, and aromatic hydrocarbons, all of which were oxygen-free compounds. Through the catalytic conversion of raw materials, waste soy bean oil (SBO) and palm fatty acid distillate (PFAD), a high-quality jet-fuel product was also obtained in a SSP. The degree of oxygen removal was approximately 95% for the conversions of SBO and PFAD.

The present work describes the development of a two-dimensional mathematical model of a pilot-scale fixed-bed reactor for Fe-based Fischer–Tropsch synthesis to evaluate the effect of tube diameter on temperature profile and catalyst performance. The entire chain lengths of the hydrocarbon products were lumped to form several representative components, and the apparent kinetic parameters for the reaction rates were estimated. The effectiveness of the developed model was corroborated by the comparison of temperature profiles, conversion, and selectivities between experimental and simulated results. The increase of tube diameter in the simulation showed that temperature increased in both the radial and the axial directions owing to the low radial heat transfer rate and the low heat transfer area, respectively. Finally, the specified diameter in the present study maintained the temperature below the threshold value and the methane selectivity below 10%.

A series of Pt/Sn/M/γ-Al2O3 catalysts with different third metal (M = Zn, In, Y, Bi, and Ga) were prepared by a sequential impregnation method for use in the direct dehydrogenation of n-butane to n-butene and 1,3-butadiene. In the direct dehydrogenation of n-butane, Pt/Sn/Zn/γ-Al2O3 catalyst showed the best catalytic performance. Catalytic performance decreased in the order of Pt/Sn/Zn/γ-Al2O3 > Pt/Sn/In/γ-Al2O3 > Pt/Sn/γ-Al2O3 > Pt/Sn/Y/γ-Al2O3 > Pt/Sn/Bi/γ-Al2O3 > Pt/Sn/Ga/γ-Al2O3. The catalytic performance increased with increasing metal–support interaction and Pt surface area of the catalyst.

X-Mg3(VO4)2/MgO–ZrO2 catalysts were prepared by a wet impregnation method with a variation of vanadium content (X = 2.8, 4.2, 5.6, 9.0, and 11.2 wt%), and they were applied to the oxidative dehydrogenation of n-butane. Effect of oxygen capacity and acidity of Mg3(VO4)2/MgO–ZrO2 catalysts on the catalytic performance in the oxidative dehydrogenation of n-butane was investigated. Experimental results revealed that oxygen capacity and acidity of catalyst were closely related to the catalytic performance in the oxidative dehydrogenation of n-butane. It was found that the catalytic performance of X-Mg3(VO4)2/MgO–ZrO2 catalysts increased with increasing oxygen capacity and with increasing acidity of the catalyst.

MgO–ZrO 2 supports with different Mg:Zr ratios (16:1, 8:1, 4:1, 2:1, and 1:1) were prepared by a gel-oxalate co-precipitation method, and Mg 3 (VO 4 ) 2 /MgO–ZrO 2 catalysts were then prepared by a wet impregnation method. The prepared catalysts were applied to the oxidative dehydrogenation of n-butane to n-butene and 1,3-butadiene. Experimental results revealed that oxygen capacity and acidity of the catalyst were closely related to the catalytic performance. Among the catalyst tested, Mg 3 (VO 4 ) 2 /MgO–ZrO 2 (4:1) catalyst, which retained the largest oxygen capacity and acidity, exhibited the best catalytic performance in the oxidative dehydrogenation of n-butane.

Vanadium-magnesium oxide (Mg3(VO4)2) catalysts supported on Al2O3, ZrO2, MgO, and CeO2 were prepared by a wet impregnation method, and they were applied to the oxidative dehydrogenation of n-butane. Effect of oxygen capacity and oxygen mobility of supported Mg3(VO4)2 catalysts on the catalytic performance in the oxidative dehydrogenation of n-butane was investigated. Experimental results revealed that large oxygen capacity of the catalyst was favorable for obtaining high catalytic activity at the initial stage of reaction, while facile oxygen mobility of the catalyst led to stable catalytic activity during the catalytic reaction in the oxidative dehydrogenation of n-butane.

Biodiesel is a renewable fuel which can be produced through an esterification reaction. The cost of feedstock which resulted in that of biodiesel is a large problem to be resolved. Dark oil from industrial process can be a better alternative for biodiesel production because of its low price. In spite of this, the study of biodiesel production using the dark oil has not been reported. This study provides technical information and catalytic properties on this system. Among the several catalysts, WO 3 /ZrO 2 catalyst was the most effective catalyst in the esterification of the dark oil to fatty acid methyl esters (FAMEs). The catalytic reaction parameters were optimized that 20 wt.% WO 3 /ZrO 2 has a high FFA conversion of 96% at 150 °C, 0.4 g/ml (oil), 1:9 (oil to alcohol, molar ratio) and 2 h reaction time. The physical and chemical properties of the catalyst were characterized by XRD, Raman spectrometer, BET and NH 3 -TPD.

To maximize the production of biodiesel from soybean soapstock, the effects of water on the esterification of high-FFA (free fatty acid) oils were investigated. Oleic acid and high acid acid oil (HAAO) were esterified by reaction with methanol in the presence of Amberlyst-15 as a heterogeneous catalyst or sulfuric acid as a homogeneous catalyst. The yield of fatty acid methyl ester (FAME) was studied at oil to methanol molar ratios of 1:3 and 1:6 and reaction temperatures of 60 and 80 °C. The rate of esterification of oleic acid significantly decreased as the initial water content increased to 20% of the oil. The activity of Amberlyst-15 decreased more rapidly than that of sulfuric acid, due to the direct poisoning of acid sites by water. Esterification using sulfuric acid was not affected by water until there was a 5% water addition at a 1:6 molar ratio of oil to methanol. FAME content of HAAO prepared from soapstock rapidly increased for the first 30 min of esterification. Following the 30-min mark, the rate of FAME production decreased significantly due to the accumulation of water. When methanol and Amberlyst-15 were removed from the HAAO after 30 min of esterification and fresh methanol and a catalyst were added, the time required to reach 85% FAME content was reduced from 6 h to 1.8 h.

To produce biodiesel from high free fatty acid (FFA) oils, the esterification characteristics of two kinds of heterogeneous acid catalysts, Amberlyst 15 and Amberlyst BD20, were compared. When the FFA contents of oils were 50.0 and 99.8 wt%, the activity of Amberlyst 15 gradually decreased with recycling, whereas the activity of Amberlyst BD20 was maintained during recycling. The activity of Amberlyst 15 was inhibited by the water produced during the esterification process, but the activity of Amberlyst BD20 was not similarly affected by water. In images obtained with a scanning electron microscope (SEM), many pores were seen within the Amberlyst 15 catalyst, whereas Amberlyst BD20 showed few pores. Despite the fact that the pores of the catalyst play a role in increasing the number of active sites, Amberlyst BD20, which had fewer pores, was deemed to have more desirable performance in reducing the inhibition by water of the esterification of high FFA oils.

Biodiesel produced by the transesterification of vegetable oils (VOs) is a promising alternative fuel to diesel regarding the limited resources of fossil fuel and the environmental concerns. In this work, an environmentally benign process for the production of biodiesel from VOs using heterogeneous catalyst was developed. Na/NaOH/γ-Al2O3 heterogeneous base catalyst was firstly adopted for the production of biodiesel. A study for optimizing the reaction conditions such as the reaction time, the stirring speed, the use of co-solvent, the oil to methanol ratio, and the amount of catalyst, was performed. The Na/NaOH/γ-Al2O3 heterogeneous base catalyst showed almost the same activity under the optimized reaction conditions compared to conventional homogeneous NaOH catalyst. The basic strength of Na/NaOH/γ-Al2O3 catalyst was estimated and the correlation with the activity towards transesterification was proposed.