Synthesis of hydroxylamine sulfate via NO hydrogenation on Pt/graphite catalysts: II. Influence of the reaction conditions and physicochemical state of the catalyst on the product yields

2019 ◽  
Vol 19 (4) ◽  
pp. 275-288
Author(s):  
A. N. Bobrovskaya ◽  
P. A. Simonov ◽  
A. V. Bukhtiyarov ◽  
R. I. Kvon ◽  
A. V. Romanenko
Keyword(s):  
Catalyst Concentration ◽  
Catalytic Properties ◽  
Concentrated Suspensions ◽  
Reaction Conditions ◽  
Specific Behavior ◽  
Transition Range ◽  
Supported Platinum ◽  
Physicochemical State ◽  
Commercial Process ◽  
Hydroxylamine Sulfate

The dependence of the selectivity to products of the commercial process for NO hydrogenation in the H2SO4 solution on process parameters such as the flow rate of the NO + H2 mixture through the reactor, stirring intensity, concentration of the Pt/graphite catalyst in the suspension and temperature was studied. In the process in the mode of external diffusion of the reactant gases, the first or zero order was observed with respect to the catalyst depending on the catalyst concentration in the suspension, the selectivity to the solid products – hydroxylamine sulfates (HAS) and ammonium – being maximal in the transition range. It was shown that the selectivity to HAS increased upon functionalization of the graphite surface with nitrogen-containing groups that led to modifying the adsorbing and catalytic properties of the supported platinum nanoparticles. Specific behavior of platinum catalysts in concentrated suspensions at the limited feeding reactant gases was discussed.

Optimization of biodiesel synthesis under simultaneous ultrasound-microwave irradiation using response surface methodology (RSM)

2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Seyed Mohammad Safieddin Ardebili ◽  
Teymor Tavakoli Hashjin ◽  
Barat Ghobadian ◽  
Gholamhasan Najafi ◽  
Stefano Mantegna ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Microwave Irradiation ◽  
Response Surface ◽  
Palm Oil ◽  
Catalyst Concentration ◽  
Irradiation Time ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Biodiesel Synthesis

AbstractThis work investigates the effect of simultaneous ultrasound-microwave irradiation on palm oil transesterification and uncovers optimal operating conditions. Response surface methodology (RSM) has been used to analyze the influence of reaction conditions, including methanol/palm oil molar ratio, catalyst concentration, reaction temperature and irradiation time on biodiesel yield. RSM analyses indicate 136 s and 129 s as the optimal sonication and microwave irradiation times, respectively. Optimized parameters for full conversion (97.53%) are 1.09% catalyst concentration and a 7:3.1 methanol/oil molar ratio at 58.4°C. Simultaneous ultrasound-microwave irradiation dramatically accelerates the palm oil transesterification reaction. Pure biodiesel was obtained after only 2.2 min while the conventional method requires about 1 h.

Optimization of Esterification Reaction Conditions Through the Analysis of the Main Significant Variables

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Bruna Ricetti Margarida ◽  
Luana I. Flores ◽  
Luiz Fernando De Lima Luz Jr. ◽  
Marcelo Kaminski Lenzi
Keyword(s):  
Catalyst Concentration ◽  
Biodiesel Production ◽  
Major Influence ◽  
Esterification Reaction ◽  
Reaction Conditions ◽  
Reaction Behavior ◽  
Reaction Conversion ◽  
Depth Analysis ◽  
Hydrous Ethanol ◽  
Water Ratio

Biodiesel production from residual sources is gaining considerable attention nowadays. Consequently, many different studies with in-depth analysis concerning the influence of the transesterification reaction conditions are available in the literature. However, further evaluation of the esterification of fatty acids in the biodiesel industry is still needed. In this study, different parameters influencing the esterification reaction behavior using ethanol as the alcohol and lauric acid as the FFA are analyzed through factorial design and ANOVA methodologies to verify which ones are significant in the reaction. In total, four parameters were evaluated: temperature, catalyst concentration, ethanol/FFA ratio, and ethanol/water ratio. The temperature and ethanol/water ratio had a major influence on the reaction, as increasing these parameters greatly improved reaction conversion. It was also verified that using hydrous ethanol in the esterification reaction is possible in some conditions.

Selective aerobic allylic oxidation of α-pinene catalyzed by metalloporphyrins in the absence of solvents and additives

2019 ◽  
Vol 43 (9-10) ◽  
pp. 419-425 ◽  
Author(s):  
Huanhuan Dong ◽  
Shichao Xu ◽  
Jing Wang ◽  
Yuxiang Chen ◽  
Liangwu Bi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Flow Rate ◽  
Catalyst Concentration ◽  
Aerobic Oxidation ◽  
Oxygen Flow Rate ◽  
Oxidation Products ◽  
Allylic Oxidation ◽  
Temperature Reaction ◽  
Reaction Conditions

Selective aerobic oxidation of α-pinene to high-value products is a major challenge in chemistry. Metalloporphyrins are proved to be selective catalysts for aerobic oxidation of simple hydrocarbons. Herein, we extend this method to more complex substrates using metallodeuteroporphyrins as model catalysts. It was found that the oxidation occurs mainly on the C=C and allylic C–H bonds of α-pinene influenced by the reaction temperature, reaction time, catalyst concentration, and oxygen flow rate. Allylic C–H oxidation products are obtained with a maximum selectivity value of 78.4% using the following reaction conditions: 105°C, 7 h, 5 ppm, and 60 mL/min. The influence of the metal nuclei of the metallodeuteroporphyrins on this reaction is also investigated. It was found that metallodeuteroporphyrins with Fe3+ as the metal nucleus exhibit the highest catalytic activity.

Synthesis of Hydroxylamine Sulfate via NO Hydrogenation over Pt/Graphite Catalysts. I: Physicochemical State of Platinum Particles and the Surface of the Support in the Catalysts

2018 ◽  
Vol 10 (4) ◽  
pp. 279-287 ◽  
Author(s):  
A. N. Bobrovskaya ◽  
P. A. Simonov ◽  
A. V. Bukhtiyarov ◽  
R. I. Kvon ◽  
N. A. Rudina ◽  
...  
Keyword(s):  
Platinum Particles ◽  
Physicochemical State ◽  
Hydroxylamine Sulfate

Oligomerization of pent-1-ene over zeolite catalysts

2019 ◽  
Vol 19 (4) ◽  
pp. 307-315
Author(s):  
N. G. Grigoryeva ◽  
D. V. Serebrennikov ◽  
S. V. Bubennov ◽  
B. I. Kutepov
Keyword(s):  
Catalytic Properties ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Main Reaction ◽  
Reaction Products ◽  
High Concentration ◽  
Reaction Conditions ◽  
One Dimensional ◽  
Fuel Components ◽  
Channel Systems

Oligomerization of pent-1-ene is an effective process for synthesis of high-quality environmentally friendly fuel components. Catalytic properties of H-zeolites FAU, OFF, MOR, ВЕА, MTW and MFI were studied for synthesis of pentene oligomers in an autoclave at 110–200 °C. The wide-pore structure of H-Y and H-Beta (18) zeolites and the high concentration of acid sites were established to cause the high oligomerization activity to obtain 97–100 % yields of oligomers. Oligomers obtained over these catalysts comprised, depending on the reaction conditions, 30–73 % dimers, 25–50 % trimers and 2–14 % oligomers with more than three monomer units (n > 3). Fine-pore zeolites (H-ZSM-5) and zeolites with one-dimensional channel systems (H-OFF, H-MOR, H-ZSM-12) were less active to oligomerization of pent-1-ene, decenes being the main reaction products.

Impregnated Molecular Sieves as a Catalyst for the Isopropylation of Naphthalene

2013 ◽  
Vol 329 ◽  
pp. 45-50 ◽  
Author(s):  
Xin Zhang ◽  
Xi Dong Liu
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Molecular Sieves ◽  
Catalytic Properties ◽  
Fixed Bed ◽  
Optimum Conditions ◽  
Reaction Conditions ◽  
Energy Dispersion Spectrometer ◽  
Micro Reactor ◽  
Scanning Electron

At refluence temperature, ferric chloride impregnated molecular sieves were prepared by impregnation of FeCl3 through ion-exchanging methods. The above catalysts were characterized by the means of SEM/EDS (scanning electron microscope/energy dispersion spectrometer) and BET. The catalytic properties on isopropylation of naphthalene and effect of reaction conditions were carried out with fixed-bed flow micro-reactor. We obtained the optimum conditions of this reaction. At this condition, the conversion of naphthalene reaches 44.1%, the yield of 2, 6-DIPN is 41.2% and the selectivity of β,β-DIPN is 85.2%.

Preparation and Catalytic Properties of BaSb2O6 Photocatalyst

2014 ◽  
Vol 809-810 ◽  
pp. 867-871
Author(s):  
Xiu Ping Han ◽  
Bing Hua Yao ◽  
Qin Ku Zhang ◽  
Cai Ling Zhang
Keyword(s):  
Methylene Blue ◽  
Fine Particles ◽  
Catalytic Properties ◽  
Photocatalytic Efficiency ◽  
Reaction Conditions ◽  
Xrd Pattern ◽  
X Ray ◽  
Standard Card ◽  
Temperature Time ◽  
Scanning Electron

The small-stones-like BaSb2O6 had been successfully prepared through two-step reaction by using inexpensive Sb2O3 reactant. The effects of reaction conditions (temperature, time) on photocatalytic efficiency were researched. The photocatalytic activity of BaSb2O6 was evaluated by photodegradation of methylene blue (MB). The results showed that the decolorization rate of methylene blue was over 90% under ultraviolet lamp (500 W) beam for 40min. Its structures and morphologies had been investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM). The results showed that XRD pattern of BaSb2O6 was consistent with standard card and morphology of BaSb2O6 was smooth close-packed state "small stones", fine particles & no agglomeration.

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