New approach on the modification of liquid natural rubber production using microwave technique

High-speed synthesis using microwave technique has attracted considerable intentions among researchers as it provides an efficient time of doing reactions. Modification of liquid natural rubber (LNR) via hydrogenation using of 2,4,6-trimethylbenzenesulfonylhydrazide (MSH) produced hydrogenated liquid natural rubber (HLNR). The results showed that microwave-assisted hydrogenation of LNR was experimentally found to give expected product in a short time (10–20 min). The structure of products was characterized by Fourier-transform infrared (FTIR) and the percentage of hydrogenation was determined from the 1H-NMR spectrum. The highest hydrogenation percentage of HLNR for hydrogenation of LNR by microwave heating were obtained; an LNR hydrogenation percentage of 41.18% at a MSH:LNR weight ratio of 1.5:1, a microwave power of 600 W and a reaction time of 20 min. Diimide molecules have been generated more quickly at microwave frequencies and yield HLNR in a shorter time compared to reflux heating method

Development of bimetallic and trimetallic oxides doped on molybdenum oxide based material on oxidative desulfurization of diesel

Catalytic oxidative desulfurization (Cat-ODS) activities of thiophenic sulfur were compared using alumina supported of mono-, bi- and trimetallic oxide molybdena based catalysts, prepared by incipient wetness impregnation. The aim of this study was to inquire on the possibility of supported trimetallic oxide catalysts for deep Cat-ODS process. The prepared catalysts were characterized by nitrogen adsorption, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy, and tested in the ODS of model thiophene, dibenzothiophene and 4,6-dimethyldibenzothiphene, as well as on commercial and crude diesel. It was found that the addition of dopant and co-dopant toward MoO3/Al2O3 catalysts increased significantly the selectivity of catalytic performance in the order: mono- 90% of sulfur was removed in both commercial and crude diesel under similar reaction conditions. Reproducibility test showed that the catalyst has higher catalytic activity and could be repeatedly used with little change after five cycles

Development of bimetallic and trimetallic oxides doped on molybdenum oxide based material on oxidative desulfurization of diesel

Catalytic oxidative desulfurization (Cat-ODS) activities of thiophenic sulfur were compared using alumina supported of mono-, bi- and trimetallic oxide molybdena based catalysts, prepared by incipient wetness impregnation. The aim of this study was to inquire on the possibility of supported trimetallic oxide catalysts for deep Cat-ODS process. The prepared catalysts were characterized by nitrogen adsorption, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy, and tested in the ODS of model thiophene, dibenzothiophene and 4,6-dimethyldibenzothiphene, as well as on commercial and crude diesel. It was found that the addition of dopant and co-dopant toward MoO3/Al2O3 catalysts increased significantly the selectivity of catalytic performance in the order: mono-90% of sulfur was removed in both commercial and crude diesel under similar reaction conditions. Reproducibility test showed that the catalyst has higher catalytic activity and could be repeatedly used with little change after five cycles

Investigation of active species in methanation reaction over cerium based loading

A series of cerium oxide based catalyst has been studied by various cerium loadings that calcined at 1000oC using wet impregnation method. The potential Ru/Mn/Ce (5:35:60) /Al2O3 catalyst calcined at 1000oC was characterized using XRD, XPS, and BET analyses. As could be observed from the XRD analysis, at Ce ratio of 55% and 65%, both revealed the presence of RuO2 with tetragonal phase and intense, sharper peaks indicating to high crystallinity and in line with lower surface area, 50.95 m2/g in BET analysis. Meanwhile, CeO2 (cubic phase) and MnO2 (tetragonal phase) were also observed for 55%, 60%, and 65%, respectively. However, the presence of Al2O3 with rhombohedral phase at 55% and 65% was revealed as an inhibitor which decreased the CO2 conversion. The presence of active species on Ru/Mn/Ce (5:35:60) /Al2O3 catalyst has been confirmed using XPS analysis with the deconvolation peaks belonged to Ce4+ with the formation of CeO2 compound and Mn4+ for MnO2. The product formed in catalytic methanation was proposed to be H2O and CH3OH from GC and HPLC analysis

Effectiveness of Ru/Mg/Ce supported on alumina catalyst for direct conversion of syngas to methane: Tailoring activity and physicochemical studies

The century of urbanisation and industrialisation had a great impact on the environment due to the rapid growth of the flue gas sectors. Thus, green technology is enforced to convert carbon dioxide (CO2) gas into methane (CH4) gas as an alternative fuel in electricity generation, particularly coal and natural gas sources. Cerium (Ce) was recognised as one of the most basic and unique redox characteristics utilised in the promising methanation reaction among catalysts used. The trimetallic catalyst used in this work was prepared with Ce as the based catalyst and ruthenium/magnesium (Ru/Mg) as the impregnated metal. Response surface methodology projected the CO2 conversion to be less than 0.3% of the experimental value of 78.82% using the indicated parameters of 593 °C calcination temperature and 61 wt.% ratios. Ru/Mg/Ce/Al2O3 catalyst with 60 wt.% of Ce loading calcined at 600 °C produced 58.08% of CH4. The characterisation results revealed that CeO2, Mg(Al2O4), and RuO2 species were the active species for CO2 methanation selectivity, as observed in XRD and XPS analyses. The mesoporous structure and particle agglomeration resulted in a surface area of 147 m2/g

Optimization and physicochemical studies of alumina supported samarium oxide based catalysts using artificial neural network in methanation reaction

Developed countries are increasing their demand for natural gas as it is an industrial requirement for fuel transportation. Most of modern society relies heavily on vehicles. However, the presence of CO2 gas has led to the categorization of sour natural gas which reduces the quality and price of natural gas. Therefore, the catalytic methanation technique was applied to convert carbon dioxide (CO2) to methane (CH4) gas and reduce the emissions of CO2 within the environment. In this study, samarium oxide supported on alumina doped with ruthenium and manganese was synthesized via wet impregnation. X-ray diffraction (XRD) analysis revealed samarium oxide, Sm2O3 and manganese oxide, MnO2 as an active species. The reduction temperature for active species was at a low reaction temperature, 268.2oC with medium basicity site as in Temperature Programme Reduction (TPR) and Temperature Programme Desorption (TPD) analyses. Field Emission Scanning Electron Microscopy (FESEM) analysis showed an agglomeration of particle size. The characterised potential catalyst of Ru/Mn/Sm (5:35:60)/Al2O3 (RMS 5:35:60) calcined at 1,000oC revealed 100% conversion of CO2 with 68.87% CH4 formation at the reaction temperature of 400oC. These results were verified by artificial neural network (ANN) with validation R2 of 0.99 indicating all modelling data are acceptable

Effect of transition metal oxides catalysts on oxidative desulfurization of model diesel

In this paper, model diesel is used to study the performance of oxidative desulfurization (ODS) system compared to hydrodesulfurization (HDS) process. A detailed parametric experimental study was performed to select the best technique for sulfur removal. The effects of solvent, oxidant, bimetallic oxide catalyst, dopant, dopant ratio and calcination temperature were investigated. Dimethylformamide (DMF) and tert-butyl hydroperoxide (TBHP) were found to be the best solvent and oxidizing agent for the removal of sulfur compounds in model diesel. Both solvent and oxidant were then applied to explore the applicability of various catalysts, such as iron, manganese, molybdenum, tin, zinc and cobalt in model diesel. The results showed that the catalytic activity was decreased in the order: Mo > Mn > Sn > Fe ˜ Co > Zn. Further investigation of doped molybdenum revealed that 4.35% WO3/16.52% MoO3/Al2O3 in the ratio of 10:90 with calcination temperature at 500 °C was assigned as the best catalyst in this research. Under mild reaction condition, this catalyst showed high conversion with appreciable stability until 150 hours and can be used as a reusable active catalyst in ODS treatment. Additionally, on the basis results obtained, a mechanistic proposal for this reaction was postulated, as an oxidation mechanism by nucleophilic attack of the sulfur atom on peroxo species of WO3/MoO3/Al2O3

The role of molybdenum oxide based catalysts on oxidative desulfurization of diesel fuel

The industrial technology, hydrodesulfurization (HDS) is incapable to meet ultra-low sulfur standard due to the limited treatment on organosulfur compound in diesel fuel. In this paper, catalytic oxidative desulfurization of thiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene using molybdenum oxide based catalyst was investigated. A detailed parametric experimental study; number of coating, calcination temperature, addition of dopant was performed on sulfur removal. It was shown that 4.35% WO3/16.52% MoO3/γ-Al2O3 , calcined at 500°C was successfully removed 92.5% of thiophene, 100% of DBT and 100% of 4,6-DMDBT in model diesel at short reaction time and lower temperature

Catalytic oxidative desulfurization of diesel oil by Co/Mn/Al2O3 catalysts-tert-butyl hydroperoxide (TBHP) system: preparation, characterization, reaction, and mechanism

The hydrodesulfurization (HDS) technique available is no longer suitable for the purpose of achieving ultra-low sulfur diesel. Therefore, in this study, the catalytic oxidative desulfurization of model diesel was carried out using tert-butyl hydroperoxide along with inexpensive alumina-supported manganese-based oxide catalysts, and later, the oxidized sulfur compounds were extracted by dimethylformamide, a polar solvent. The effect of dopant ratio, calcination temperature, reaction time, and reaction temperature were investigated in detail. The oxidation reactivity of different substrates was in the following order: DBT > Th > 4,6-DMDBT. The best desulfurization efficiency of model diesel, under mild reaction conditions, was 85.3 % thiophene, 85.0 % dibenzothiophene, and 74.5 % 4,6-dimethyldibenzothiophene using the 2.14 %Co/13.17 %Mn/Al2O3 catalyst calcined at 400 °C. Besides, this catalyst retained a high conversion of sulfur after three rounds of reaction cycles and can be used as a reusable active catalyst in ODS treatment. Under the optimal conditions, the S-content in the commercial diesel could be decreased from 415 to less than 10 ppmw. The oxidation mechanism was studied in detail, and TBHP-Co/Mn catalyst was the main active oxidizing species on the oxidation of DBT

Role of Mn/Al2O3 catalyst in deep oxidative desulfurization of diesel

In this work, a series of supported manganese catalyst has been synthesized and utilized in oxidative desulfurization to remove 4,6-dimethyldibenzothiophene (4,6-DMDBT), dibenzothiophene (DBT) and thiophene. The influences of catalyst parameters were investigated including manganese precursors, manganese loading and calcination temperature in details. The synthesized catalyst was characterized by scanning electron microscopy (SEM), N2 adsorption/desorption and X-ray diffraction (XRD) techniques. 90.2% of 4,6-DMDBT, 98.5% of DBT and 95.5% of thiophene conversion were achieved under mild operational conditions using 3Mn(NO3)2/Al2O3 at 500 °C calcination temperature. A slight decrease in desulfurization activity was observed after Mn/Al2O3 catalyst being used in five cycles ODS