scholarly journals Hydrodeoxygenation of Xylose Isopropylidene Ketal Over Pd/HBEA Catalyst for the Production of Green Fuels

2021 ◽  
Vol 9 ◽  
Author(s):  
Matheus O. Souza ◽  
Sergio C. Pereira ◽  
Lam Y. Lau ◽  
Leandro Soter ◽  
Marcelo M. Pereira
Keyword(s):  
Reaction Time ◽  
Active Sites ◽  
Hydrogen Pressure ◽  
Aldol Condensation ◽  
Batch Reactor ◽  
Initial Period ◽  
Oxygenated Compounds ◽  
Viscous Oil ◽  
Products Analysis ◽  
Green Fuels

1,2:3,5-Di-O-isopropylidene-α-D-xylofuranose (DX) is a major component of a new bio-crude: a viscous oil presenting petroleum-friendly properties produced by the ketalization of sugarcane bagasse. This article studies DX HDO (hydrodeoxygenation) over a Pd/HBEA catalyst in a batch reactor at 250°C. The effects of hydrogen pressure from 10 to 40 bar, catalyst/DX ratio from ½ to 2, and reaction time 0–24 h were investigated. A range of conditions for complete hydrodeoxygenated DX into alkanes with a Pd/HBEA catalyst was found. In these conditions, a low coke yield with water as the principal deoxygenated product was obtained. Further, higher amounts of alkanes containing seven or more carbons (A7+) were favored at 30 bar of hydrogen pressure, Cat/DX ratio = 2, and short reaction time. Products analysis that accompanied the above variations during reaction time led to general insights into reaction pathways. First, in the presence of DX, an effective n-hexane conversion was not observed on experiments of low catalyst/DX ratio (½) or in the initial period of high Cat/DX ratio, suggesting DX is much more successful than n-hexane to compete for active sites. Then, the formation of a pool of oxygenated compounds, such as furans, ketones, and carboxylic acids, along with lighter and heavier alkanes was observed. Hence, the aforementioned oxygenates may undergo reactions, such as aldol condensation with subsequent hydrodeoxygenation reaction, generating heavier alkanes.

scholarly journals Highly Active CuFeAl-containing Catalysts for Selective Hydrogenation of Furfural to Furfuryl Alcohol

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 816 ◽  
Author(s):  
Svetlana A. Selishcheva ◽  
Andrey A. Smirnov ◽  
Alexander V. Fedorov ◽  
Olga A. Bulavchenko ◽  
Andrey A. Saraev ◽  
...  
Keyword(s):  
Furfuryl Alcohol ◽  
Active Sites ◽  
Hydrogen Pressure ◽  
Batch Reactor ◽  
Metallic Copper ◽  
Space Velocity ◽  
Oxide Content ◽  
X Ray Diffraction ◽  
Highly Active ◽  
Xrd Method

CuFe-containing catalysts with different copper oxide content were prepared by fusion of metal salts. The obtained catalyst showed high activity in the hydrogenation of furfural to furfuryl alcohol (FA) in the batch reactor in the presence of isopropanol as a solvent at a temperature of 100 °C and a hydrogen pressure of 6.0 MPa. The yield of FA and furfural conversion are 97% and 98%, respectively. In the solvent-free reaction in the flow-type reactor; the most active catalyst Cu20Fe66Al14 leads to the 96% formation of FA with 100% conversion of furfural at liquid hourly space velocity (LHSV) = 1 h−1; 160 °C and a hydrogen pressure of 5.0 MPa during 30 h. According to the X-ray diffraction (XRD) method, the active component of the spent and fresh Cu20Fe66Al14 catalyst is the same and is represented by metallic copper and Fe3O4-type spinel. Using different methods, the formation of active sites was investigated.

Revisiting Glycerol Esterification with Acetic Acid over Amberlyst-35 via Statistically Designed Experiments: Overcoming Transport Limitations

2019 ◽  
Author(s):  
Víctor Gabriel Baldovino Medrano ◽  
Karen V. Caballero ◽  
Hernando Guerrero-Amaya
Keyword(s):  
Acetic Acid ◽  
Active Sites ◽  
Batch Reactor ◽  
Catalyst Particle ◽  
Experimental Designs ◽  
Particle Sizes ◽  
Turnover Rates ◽  
Designed Experiments ◽  
Different Temperatures ◽  
Glycerol Esterification

Turnover rates for glycerol esterification with acetic acid over Amberlyst-35 were measured under different temperatures, reactants and active sites concentrations, and catalyst particle sizes. Data were collected in a batch reactor. Experiments were done following a sequence of factorial experimental designs.

Optimization and statistical analysis of sono-Fenton treated wastewater of food industry using reactor by response surface method

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vijay A. Juwar ◽  
Ajit P. Rathod
Keyword(s):  
Reaction Time ◽  
Response Surface ◽  
Food Industry ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Experimental Result ◽  
Molar Ratio

Abstract The present study deals with the treatment of complex waste (WW) treated for removal of chemical oxygen demand (COD) of the food industry by a sono-Fenton process using a batch reactor. The response surface methodology (RSM) was employed to investigate the five independent variables, such as reaction time, the molar ratio of H2O2/Fe2+, volume ratio of H2O2/WW, pH of waste, and ultrasonic density on COD removal. The experimental data was optimized. The optimization yields the conditions: Reaction time of 24 min, HP:Fe molar ratio of 2.8, HP:WW volume ratio of 1.9 ml/L, pH of 3.6 and an ultrasonic density of 1.8 W/L. The predicted value of COD was 91% and the experimental result was 90%. The composite desirability value (D) of the predicted percent of COD removal at the optimized level of variables was close to one (D = 0.991).

scholarly journals NiMo-sulfide supported on activated carbon to produce renewable diesel

2017 ◽  
Vol 22 (1) ◽  
pp. 71 ◽  
Author(s):  
Juan Tapia ◽  
Nancy Y Acelas ◽  
Diana López ◽  
Andrés Moreno
Keyword(s):  
Activated Carbon ◽  
Batch Reactor ◽  
Liquid Hydrocarbon ◽  
Product Distribution ◽  
Impregnation Method ◽  
Carbon Supports ◽  
Gaseous Products ◽  
Oxygenated Compounds ◽  
Metal Support Interaction ◽  
Metal Support

Due to their weak polarity and large surface area, activated carbon supports have the potential to enhance the dispersion of metal-sulfides. It is expected that the absence of a strong metal-support interaction can result in the formation of a very active and stable Ni-Mo-S phase. In this study, catalysts with different amounts of nickel and molybdenum supported on a commercial activated carbon were prepared by a co-impregnation method and characterized by BET, XRF, and SEM techniques. The catalytic activity for hydroprocessing of Jatropha oil was evaluated in a batch reactor, and the composition of the liquid and gaseous products were determined. Results showed that gaseous products are mainly composed of high amounts of propane and small amounts of other light hydrocarbons (C1 to C5). Liquid hydrocarbon products consisted of a mixture containing mainly n-paraffins of C15-C18 and some oxygenated compounds. The catalysts with a mass fraction<br />of 3 % Ni, 15 % Mo (Ni3Mo15/AC) presented the highest selectivity toward C17-C18 hydrocarbons, with a product distribution similar to a commercial<br />alumina-supported Ni-Mo-S catalyst.

scholarly journals Influence of Bio-Oil Phospholipid on the Hydrodeoxygenation Activity of NiMoS/Al2O3 Catalyst

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 418 ◽  
Author(s):  
Muhammad Abdus Salam ◽  
Derek Creaser ◽  
Prakhar Arora ◽  
Stefanie Tamm ◽  
Eva Lind Grennfelt ◽  
...  
Keyword(s):  
Active Sites ◽  
Batch Reactor ◽  
Active Phase ◽  
Aluminum Phosphate ◽  
Spent Catalyst ◽  
Bio Oil ◽  
Pore Blockage ◽  
Sulfided Catalyst ◽  
High Degree

Hydrodeoxygenation (HDO) activity of a typical hydrotreating catalyst, sulfided NiMo/γ-Al2O3 for deoxygenation of a fatty acid has been explored in a batch reactor at 54 bar and 320 °C in the presence of contaminants, like phospholipids, which are known to be present in renewable feeds. Oleic acid was used for the investigation. Freshly sulfided catalyst showed a high degree of deoxygenation activity; products were predominantly composed of alkanes (C17 and C18). Experiments with a major phospholipid showed that activity for C17 was greatly reduced while activity to C18 was not altered significantly in the studied conditions. Characterization of the spent catalyst revealed the formation of aluminum phosphate (AlPO4), which affects the active phase dispersion, blocks the active sites, and causes pore blockage. In addition, choline, formed from the decomposition of phospholipid, partially contributes to the observed deactivation. Furthermore, a direct correlation was observed in the accumulation of coke on the catalyst and the amount of phospholipid introduced in the feed. We therefore propose that the reason for the increased deactivation is due to the dual effects of an irreversible change in phase to aluminum phosphate and the formation of choline.

Photocatalytic degradation of azo dye in TiO2 suspended solution

2001 ◽  
Vol 43 (2) ◽  
pp. 313-320 ◽  
Author(s):  
C.-H. Hung ◽  
P.-C. Chiang ◽  
C. Yuan ◽  
C.-Y. Chou
Keyword(s):  
Reaction Time ◽  
Light Intensity ◽  
Photocatalytic Degradation ◽  
Azo Dye ◽  
Batch Reactor ◽  
Reaction Rates ◽  
Pseudo First Order Reaction ◽  
Degradation Rates ◽  
Orange G ◽  
Degradation Of Azo Dye

The photocatalysis of azo dye, Orange G, by P-25 anatase TiO2 was investigated in this research. The experiments were conducted in a batch reactor with TiO2 powder suspension. Four near-UV lamps were used as the light source. The experimental variables included solution pH level, amount of TiO2, illumination light intensity, and reaction time. A pseudo-first order reaction kinetic was proposed to simulate the photocatalytic degradation of Orange G in the batch reactor. More than 80% of 10 mg/L Orange G decomposition in 60-minute reaction time was observed in this study and fast decomposition of Orange G only occurred in the presence of both TiO2 and suitable light energy. Faster degradation of Orange G was achieved under acid conditions. The degradation rates of Orange G at pH = 3.0 were about two times faster than those at pH = 7.0. Faster degradation of azo dye was observed for greater irradiated light intensity and more TiO present during the reaction. The reaction rates were proportional to TiO2concentration and light intensity with the power order of 0.726 and 0.734, respectively.

Catalytic routes to fuels from C1 and oxygenate molecules

2017 ◽  
Vol 197 ◽  
pp. 9-39 ◽  
Author(s):  
Shuai Wang ◽  
Iker Agirrezabal-Telleria ◽  
Aditya Bhan ◽  
Dante Simonetti ◽  
Kazuhiro Takanabe ◽  
...  
Keyword(s):  
Transition State ◽  
Active Sites ◽  
Aldol Condensation ◽  
Bond Formation ◽  
Transition States ◽  
Solid Acids ◽  
State Theory ◽  
Side Reactions ◽  
Oh Radicals ◽  
Acid Base

This account illustrates concepts in chemical kinetics underpinned by the formalism of transition state theory using catalytic processes that enable the synthesis of molecules suitable as fuels from C1 and oxygenate reactants. Such feedstocks provide an essential bridge towards a carbon-free energy future, but their volatility and low energy density require the formation of new C–C bonds and the removal of oxygen. These transformations are described here through recent advances in our understanding of the mechanisms and site requirements in catalysis by surfaces, with emphasis on enabling concepts that tackle ubiquitous reactivity and selectivity challenges. The hurdles in forming the first C–C bond from C1 molecules are illustrated by the oxidative coupling of methane, in which surface O-atoms form OH radicals from O2 and H2O molecules. These gaseous OH species act as strong H-abstractors and activate C–H bonds with earlier transition states than oxide surfaces, thus rendering activation rates less sensitive to the weaker C–H bonds in larger alkane products than in CH4 reactants. Anhydrous carbonylation of dimethyl ether forms a single C–C bond on protons residing within inorganic voids that preferentially stabilize the kinetically-relevant transition state through van der Waals interactions that compensate for the weak CO nucleophile. Similar solvation effects, but by intrapore liquids instead of inorganic hosts, also become evident as alkenes condense within MCM-41 channels containing isolated Ni2+ active sites during dimerization reactions. Intrapore liquids preferentially stabilize transition states for C–C bond formation and product desorption, leading to unprecedented reactivity and site stability at sub-ambient temperatures and to 1-alkene dimer selectivities previously achieved only on organometallic systems with co-catalysts or activators. C1 homologation selectively forms C4 and C7 chains with a specific backbone (isobutane, triptane) on solid acids, because of methylative growth and hydride transfer rates that reflect the stability of their carbenium ion transition states and are unperturbed by side reactions at low temperatures. Aldol condensation of carbonyl compounds and ketonization of carboxylic acids form new C–C bonds concurrently with O-removal. These reactions involve analogous elementary steps and occur on acid–base site pairs on TiO2 and ZrO2 catalysts. Condensations are limited by α-H abstraction to form enolates via concerted interactions with predominantly unoccupied acid–base pairs. Ketonization is mediated instead by C–C bond formation between hydroxy-enolates and monodentate carboxylates on site pairs nearly saturated by carboxylates. Both reactions are rendered practical through bifunctional strategies, in which H2 and a Cu catalyst function scavenge unreactive intermediates, prevent sequential reactions and concomitant deactivation, and remove thermodynamic bottlenecks. Alkanal–alkene Prins condensations on solid acids occur concurrently with alkene dimerization and form molecules with new C–C bonds as skeletal isomers unattainable by other routes. Their respective transition states are of similar size, leading to selectivities that cannot sense the presence of a confining host. Prins condensation reactions benefit from weaker acid sites because their transition states are less charged than those for oligomerization and consequently less sensitive to conjugate anions that become less stable as acids weaken.

Denitrification with corncob as carbon source and biofilm carriers

2012 ◽  
Vol 65 (7) ◽  
pp. 1238-1243 ◽  
Author(s):  
Guochao Li ◽  
Jie Chen ◽  
Tao Yang ◽  
Jianqi Sun ◽  
Shenglu Yu
Keyword(s):  
Reaction Time ◽  
Carbon Source ◽  
Nitrate Nitrogen ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Limiting Factor ◽  
Nitrate N ◽  
Biofilm Carrier ◽  
Laboratory Reactor ◽  
Control Batch

In this research the agricultural by-product corncob was investigated as a carbon source as well as a biofilm carrier to remove organic matter, expressed as chemical oxygen demand (COD) and nitrate nitrogen (nitrate-N), from wastewater in a batch laboratory reactor. The performance of a reactor with corncob as the carbon source and the biofilm carrier was compared with a control batch reactor with suspended plastic carriers and glucose as the sole carbon source. With 60 vol% of corncob carriers inside the reactor, a soluble COD/N ratio of 4.2 g COD g N−1 was enough for total denitrification, nearly half of the control reactor (9.5 g COD g N−1), at 23 h reaction time. The specific denitrification rate decreased with increasing soluble COD consumption for both reactors. Nitrate and COD removal efficiencies decreased with shorter retention times, with accentuated effects in the reactor. This study suggested corncob as a feasible carbon source and that reaction time was a limiting factor with corncob used as the carbon source for denitrification.

Selective Hydrogenation of p-Chloronitrobenzene Catalyzed by FexOY@C Supported Pt-Catalyst

2014 ◽  
Vol 960-961 ◽  
pp. 221-224
Author(s):  
Jie Wu ◽  
Guang Yin Fan ◽  
Wen Jun Huang
Keyword(s):  
Reaction Time ◽  
Selective Hydrogenation ◽  
Hydrogen Pressure ◽  
Room Temperature ◽  
Catalytic Properties ◽  
Pt Nanoparticles ◽  
Pt Catalyst ◽  
Water Mixture ◽  
Supported Pt Catalyst

FexOy@C nanocomposites were synthesized and used as carriers for depositing Pt nanoparticles. Catalytic properties of the nanocomposites were investigated for the hydrogenation of p-chloronitrobenzene at room temperature and balloon hydrogen pressure. The catalyst Pt/FexOy@C was extremely active for the hydrogenation of p-chloronitrobenzene. Completely conversion of p-chloronitrobenzene was achieved with a selectivity of 99.7 % in ethanol-water mixture in a reaction time of 40 min. Moreover, it can be reused four times without loss of any activity.

scholarly journals Synthesis of silver nanoparticles using supercritical water

2018 ◽  
pp. 22-25
Author(s):  
Buyankhishig B ◽  
Narandalai B ◽  
Enkhtuul S
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Electron Microscope ◽  
Reaction Time ◽  
Supercritical Water ◽  
Silver Salt ◽  
Activated Carbons ◽  
Batch Reactor ◽  
Acetate Solution ◽  
Silver Acetate

Supercritical water (SCW) technology is a relatively novel and green method compared with others for the synthesize of metal nanoparticles. It is considered one of the most suitable methods for loading nanoparticles in surface of porous materials due to the water in supercritical conditions has a high diffusivity, well dispersive and it has a same carrier characteristic as like a gas. Silver nanoparticles and silver loaded activated carbons were synthesized using silver acetate solution under supercritical water condition at 4000C and 31.15 MPa in a batch reactor. This study was investigated effect of operational parameters on the particle size of silver nanoparticles in particularly the concen-tration of silver salt solution and the reaction time. The experiments were carried out to test the silver salt concentra-tion at 0.01 M, 0.02 M, 0.05M, and the reaction time of 15 and 30 minutes. When the silver acetate concentration and reaction time increased agglomerations of silver particles were observed on the surface of activated carbons. The structure, morphology and particle size of synthesized products were determined by X-ray diffraction (XRD), Scan-ning electron microscope (SEM) and Transmission electron microscope (TEM). Суперкртитик усан орчинд мөнгөний нанопартиклыг гарган авах Хураангуй: Суперкритик усны арга нь металлын нанопартикл гарган авах бусад аргуудтай харьцуулахад харьцангуй шинэ арга юм. Суперкритик нөхцөл дахь ус нь диффузийн коэффициент өндөртэй, тархалт сайтай, хийтэй адил зөөж тээвэрлэх шинж чанар үзүүлдэг тул сүвэрхэг материал дээр нанопартикл үүсгэхэд тохиромжтой аргуудын нэг гэж үздэг. Мөнгөний нанопартикл болон идэвхжүүлсэн нүүрсэн дээр суулгасан мөнгөний нанопартиклыг суперкритик усны аргаар мөнгөний давсны усан уусмал хэрэглэн гарган авсан. Мөнгөний нанопартиклыг гарган авахад нөлөөлөх гол хүчин зүйлүүдэд хамаарах мөнгөний давсны уусмалын концентрац болон урвал явагдах хугацааны нөлөөг судалсан бөгөөд концентрацыг 0.01 М, 0.02 М ба 0.05 М, харин урвал явагдах хугацааг 15 ба 30 минут гэсэн нөхцөлүүдэд туршилтыг явуулсан. Урвал явагдах хугацаа болон мөнгөний давсны уусмалын концентрац ихсэхэд үүссэн мөнгөний жижиг хэсгүүдийн бөөгнөрөл илүү нэмэгдэж байсан. Гарган авсан материалуудын талст бүтэц, түүний хэмжээ болон морфологийн шинж чанарыг рентген дифрактометр (XRD), сканнинг электрон микроскоп (SEM) болон нэвтрүүлэлтийн электрон микроскоп (TEM) ашиглан тодорхойлсон. Түлхүүр үг: Суперкритик ус, мөнгөний нанопартикл, урвал явагдах хугацаа, уусмалын концентрац.

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