Gas phase glycerol dehydration to acrolein over supported silicotungstic acid catalyst

Due to the various environmental concerns, a steep hike in fossil fuel price and an increasing demand of non-renewable fossil fuels consumption, the bio-basedgas-phase dehydration of glycerol to acrolein has attracted much attention recently.Thus, the gas phase dehydration of glycerol to acrolein over two groups of supported silicotungstic acid on aluminum oxide (Al2O3) nanoparticle and zirconium dioxide catalyst is being investigated in this study. The catalysts were characterized by, Xraydiffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy and energy dispersive X-ray techniques, temperature programmed desorption, thermogravimetric analysis, and elemental analyzer. The characterization results revealed that Al2O3 nano particle loading increased thermal stability, pore diameter, and specific surface area of the synthesized catalysts.Optimization by response surface methodology revealed the highest acrolein selectivity of 88.5% at 97% glycerol conversion was obtained over 30HZ-20Acatalyst with turnover frequency being 136 h-1 in 3 h for glycerol feed concentration of 10.3 wt% and 0.5 g catalyst at 300 ˚C. Coke deposition has no significant effect on the catalyst activity due to the large catalyst pore diameter (> 27 nm). The prepared catalysts were highly active and selective for acrolein production even after 40 h without any needs for gas co-feeding or application of noble metals. In addition, the kinetic study results demonstrated that glycerol dehydration to acrolein followed first-order rate with the activation energy (Ea) of 27.5 kJ/mol and frequency factor(A) of 5.35×105 s-1. Finally, the theoretical and experimental approaches confirmed no internal mass transfer limitation in glycerol dehydration reaction with catalyst pellet sizes of dp= 2-4 and 5-7 μm due to effectiveness factor equal to 1 (η=1).Calculation of the overall effectiveness factor (Ω) also confirmed the absence of external diffusion in presence of catalysts with pellet size of dp< 7 μm

A Review on the Catalytic Acetalization of Bio-renewable Glycerol to Fuel Additives

The last 20 years have seen an unprecedented breakthrough in the biodiesel industry worldwide leads to abundance of glycerol. Therefore, the economic utilization of glycerol to various value-added chemicals is vital for the sustainability of the biodiesel industry. One of the promising processes is acetalization of glycerol to acetals and ketals for applications as fuel additives. These products could be obtained by acid-catalyzed reaction of glycerol with aldehydes and ketones. Application of different supported heterogeneous catalysts such as zeolites, heteropoly acids, metal-based and acid-exchange resins have been evaluated comprehensively in this field. In this review, the glycerol acetalization has been reported, focusing on innovative and potential technologies for sustainable production of solketal. In addition, the impacts of various parameters such as application of different reactants, reaction temperature, water removal, utilization of crude-glycerol on catalytic activity in both batch and continuous processes are discussed. The outcomes of this research will therefore significantly improve the technology required in tomorrow's bio-refineries. This review provides spectacular opportunities for us to use such renewables and will consequently benefit the industry, environment and economy

Single and two-step homogeneous catalyzed transesterification of waste cooking oil: optimization by response surface methodology

Large number of studies related to alkali and acid catalyzed transesterification of waste cooking oil are widely available, but references for optimization and modeling comparison between single and two-step transesterification are scarce. Therefore, response surface methodology (RSM) has been employed to study the relationship between process variables and predict the optimal conditions. Sulfuric acid and sodium hydroxide were utilized in the pretreatment step and alkali catalyzed transesterification reaction, respectively. The highest free fatty acid (FFA) conversion in the two- and single-step reactions was 93.8% and 82.7%, respectively at the optimal reaction conditions being 1.1 wt% catalyst loading, 6.5:1 methanol to oil ratio, 60°C reaction temperature, and 65 min reaction time.RSM could accurately predict the optimal FFA conversion in both two- and single-step processes by only 0.3% and 1.01% error, respectively. In addition, the two-step method produced higher fatty acid methyl ester (FAME) yield (86.7%) and also improved the final product quality compared to single-step method with only 73.7% biodiesel yield

Supported silicotungstic acid on zirconia catalyst for gas phase dehydration of glycerol to acrolein

The gas phase dehydration of glycerol to acrolein over a series of supported silicotungstic acid (HSiW) on zirconia (10HZ, 20HZ, 30HZ and 40HZ) has been investigated. The catalysts were characterized by temperature programmed desorption, nitrogen adsorption-desorption, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy and energy dispersive X-ray techniques. The large pore diameters (>19 nm) of the prepared catalysts alleviated the coke deposition effect. Also, the specific surface area and acidity of the samples surged from 18 to 22 m2/g and 0.38 to 1.24 mmol/g cat, respectively by varying HSiW loadings from 10 to 40 wt% on zirconia. The highest acrolein yield achieved was 63.75% at 92% glycerol conversion over 30HZ catalyst for 10 wt% glycerol feed concentration and 300 C reaction temperature in 3 h. The combined physico-chemical characteristics of 30HZ made it more superior compared with other samples in the current study

Variation of density and flash point in acid degummed waste cooking oil

Recycling of waste cooking oil represents a source of convenient raw materials for industry. Within the large number of products derived from the treatment of waste cooking oil, eco-friendly lubricants grown in importance during the last years. Recycling process for such application consists usually of acid or basic degumming followed by a filtration step. The effect of the specific type of acid degumming on the density and on the flash point of the recycled oil was evaluated employing full factorial design. Two mathematical equations were derived which allow to estimate respectively the density and the flash point of the recycled oil, depending on the: (a) pH of the washing solution, (b) oil/water ratio, (c) temperature of the system, and (d) the stirring time

Structure-reactivity correlations in Vanadium containing catalysts for the one-pot glycerol oxidehydration to acrylic acid

[EN] The design of suitable catalysts for the one-pot conversion of glycerol into acrylic acid (AA) is a complex matter, as only fine-tuning of the redox and acid properties makes it possible to obtain significant yields of AA. However, fundamental understanding behind the catalytic phenomenon is still unclear. Structure-reactivity correlations are clearly behind these results, and acid sites are involved in the dehydration of glycerol into acrolein with vanadium as the main (or only) redox element. For the first time, we propose an in-depth study to shed light on the molecular-level relations behind the overall catalytic results shown by several types of V-containing catalysts. Different multifunctional catalysts were synthesized, characterized (>X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, temperature-programmed reduction, and temperature-programmed desorption of ammonia), and tested in a flow reactor. Combining the obtained results with those acquired from an in situ FTIR spectroscopy study with acrolein (a reaction intermediate), it was possible to draw conclusions on the role played by the various physicochemical features of the different oxides in terms of the adsorption, surface reactions, and desorption of the reagents and reaction products.The Instituto de Tecnologia Quimica thanks the Spanish Government-MINECO projects (CTQ2015-68951-C3-1-R and SEV-2012-0267). CIRI Energia e Ambiente (University of Bologna) is acknowledged for a Ph.D. grant to A.C. Consorzio INSTM (Firenze) is acknowledged for a Ph.D. grant to C.B.Chieregato, A.; Bandinelli, C.; Concepción Heydorn, P.; Soriano Rodríguez, MD.; Puzzo, F.; Basile, F.; Cavani, F.... (2017). Structure-reactivity correlations in Vanadium containing catalysts for the one-pot glycerol oxidehydration to acrylic acid. ChemSusChem. 10(1):234-244. https://doi.org/10.1002/cssc.201600954S234244101T. Ohara T. Sato N. Shimizu G. Prescher H. 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Efficient Acrylic Acid Production through Bio Lactic Acid Dehydration over NaY Zeolite Modified by Alkali Phosphates. ACS Catalysis, 1(1), 32-41. doi:10.1021/cs100047pChu, H. S., Ahn, J.-H., Yun, J., Choi, I. S., Nam, T.-W., & Cho, K. M. (2015). Direct fermentation route for the production of acrylic acid. Metabolic Engineering, 32, 23-29. doi:10.1016/j.ymben.2015.08.005Sheldon, R. A. (2014). Green and sustainable manufacture of chemicals from biomass: state of the art. Green Chem., 16(3), 950-963. doi:10.1039/c3gc41935eZhou, C. H., Zhao, H., Tong, D. S., Wu, L. M., & Yu, W. H. (2013). Recent Advances in Catalytic Conversion of Glycerol. Catalysis Reviews, 55(4), 369-453. doi:10.1080/01614940.2013.816610Talebian-Kiakalaieh, A., Amin, N. A. S., & Hezaveh, H. (2014). Glycerol for renewable acrolein production by catalytic dehydration. Renewable and Sustainable Energy Reviews, 40, 28-59. doi:10.1016/j.rser.2014.07.168J. L. Dubois Arkema Fr. WO 2007090991 2007J. L. Dubois Arkema Fr. 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Heterogeneous catalysis for sustainable biodiesel production via esterification and transesterification

Concern over the economics of accessing fossil fuel reserves, and widespread acceptance of the anthropogenic origin of rising CO2 emissions and associated climate change from combusting such carbon sources, is driving academic and commercial research into new routes to sustainable fuels to meet the demands of a rapidly rising global population. Here we discuss catalytic esterification and transesterification solutions to the clean synthesis of biodiesel, the most readily implemented and low cost, alternative source of transportation fuels to meet future societal demands

Optimization and kinetic model for transesterification of waste cooking oil using tungstophosphoric acid catalyst

Transesterification of waste cooking oil with heterogeneous tungstophosphoric acid (TPA) catalyst and methanol was investigated. Response Surface Methodology (RSM) and Artificial Neural Network (ANN) were employed to study the relationships of process variables on free fatty acid conversion and for predicting the optimal conditions. The highest conversion was 88.6% at optimum reaction conditions of 65 °C reaction temperature, 70:1 molar ratio of methanol to oil, 10 %wt catalyst amount, and 14 h reaction time. The RSM and ANN could accurately predict the experimental results, with R2 = 0.9987 and R2= 0.985, respectively. The TPA catalyst exhibited good potential as a stable and active catalyst over four time’s reusability. The reaction followed first-order kinetics and the calculated activation energy was Ea= 53.99 kJ/mol while the pre-exponential factor was A= 2.9x107 min-1. According to the biodiesel characterization results (ASTM D6751) the product of this study has high potential for using as a substitute for conventional catalyst in biodiesel production

Kinetic modeling, thermodynamic, and mass-transfer studies of gas-phase glycerol dehydration to acrolein over supported silicotungstic acid catalyst

The kinetics of gas-phase glycerol dehydration in a packed-bed reactor over a highly active and stable supported silicotungstic acid catalyst with zirconium oxide and nanosized aluminum oxide (30HZ-20A) was investigated. The kinetic study is based on the optimal reaction conditions determined by response surface methodology. The reaction rate followed first-order kinetics with the activation energy and frequency factor, E = 27.5 kJ/mol and A = 5.35 × 105 s-1, respectively. Based on thermodynamic analysis, the values of ΔH° and ΔS° of the endothermic reaction were 14.70 and 0.09 kJ/(mol K), respectively, and ΔG° =-12.12 kJ/mol. The mass-transfer analysis revealed the pellet sizes of dp < 1 µm proceeded under reaction-limiting conditions. Experimental results confirmed high efficacy of the tested catalyst due to unity effectiveness factor and very low Thiele modulu

Kinetic study on catalytic conversion of glycerol to renewable acrolein

Biodiesel is a suitable alternative to gasoline and diesel since it emits less carbon emission. There has been a surplus of glycerol in the market due to biodiesel production. Glycerol may be a good source of bio-based feed since it is from a renewable source. The kinetic study of gas-phase glycerol dehydration reaction using a supported γ-Al2O3 nanoparticle based solid heteropoly acid catalyst (SiW20-Al/Zr10) has been investigated. A kinetic model was established, based on the reaction mechanism, taking into account two parallel reactions of glycerol degradation into acrolein or acetol. All the reaction rate constants and activation energies were determined at various reaction temperatures (280 - 340 °C). The first-order kinetic model and the experimental data fitted-well. Results revealed that all the rate constants increased with temperature, and the activation energies of glycerol dehydration to acrolein and acetol were 46.0 and 53.3 kJ/mol. The results from this study are useful for simulation and process modelling of a bio-refinery for sustainable production of biobased chemicals