Ultrasonic Synthesis of Al-SBA-15 Nanoporous Catalyst for t-Butylation of Ethylbenzene

Mesoporous Al-SBA-15 ( Si / Al = 25 ) catalysts were synthesised by the ultrasonic (US) irradiation method at different time durations (1, 3, and 5 h) using the pluronic P123 triblock copolymer as a template. The synthesised catalysts were examined in detail by XRD, ICP-AES, N2 adsorption-desorption, SEM, TEM, FT-IR, and TGA characterization techniques. The characterization results reveal that the catalysts possess a well-ordered hexagonal mesoporous structure. The catalytic activity of synthesised materials was investigated in the tert-butylation of ethylbenzene at different reaction conditions, and their identified products are para-tert-butylethylbenzene (p-tert-BEB) and meta-tert-butylethylbenzene (m-tert-BEB). It was found that high ethylbenzene conversion (69%) is achieved at 200°C with high selectivity towards p-tert-butylethylbenzene (80%). The optimum feed ratio (ethylbenzene: t-butyl alcohol) was 1 : 2, and the feed rate was 2 ml/h for high conversion and product selectivity. All these synthesised Al-SBA-15 (US) catalysts are compared with hydrothermally synthesised Al-SBA-15 (HT) at the same reaction conditions

Acylation of isobutylbenzene with acetic anhydride on AlKIT-6 mesoporous acid catalyst

Aluminium substituted mesoporous KIT-6 materials were directly synthesized by hydrothermal method with different silica to aluminium ratios (Si/Al = 25, 50, 75, 100). These materials were obtained by using Pluronic P123 and n-butanol as a structure-directing agent and co-solvent respectively, under high acidic conditions. The prepared catalysts were characterized by small-angle XRD, ICP-AES, nitrogen sorption analysis, TGA, SEM, TEM, and XPS techniques. The characterization revealed that aluminium is mainly incorporated into the framework of KIT-6. The XRD patterns and TEM images of materials showed a highly ordered cubic Ia3d mesostructure. The incorporation of the aluminium was clearly evident from XPS and ICP-AES techniques. Further, the synthesized Al-KIT-6 catalysts were tested in the acylation of isobutylbenzene (IBB) with acetic anhydride (AA). The results revealed that Al-KIT-6 (25) was a prominent active catalyst due to silica to aluminium ratio than others. The catalytic reaction conditions were tuned to obtain a high selectivity of 4-isobutyl acetophenone (4-IBA) with high conversion of isobutylbenzene. Al-KIT-6 (25) showed a high conversion (72%) of isobutylbenzene and 94% selectivity of 4-isobutyl acetophenone

Food wastes derived adsorbents for carbon dioxide and benzene gas sorption

Food wastes are produced worldwide in large quantities that could have potential to produce higher value products, including industrial adsorbents. The present work attempts valorization of food waste by CO₂ activation and functionalization through nitric acid and melamine treatment. The prepared porous materials were subjected to gas phase adsorption of CO₂ and benzene gases. The resultant highly porous carbon materials with surface area range from 797 to 1025 m²/g were synthesized showing uptake capacities of 4.41, 4.07, 4.18 and 4.36 mmol/g of CO₂ and 345, 305, 242.5 and 380.7 mg/g of C₆H₆ respectively for PyF515, PyF520, PyF715 and PyF720 in the absence of doped carbon matrix. Differential thermogravimetric (DTG) analysis showed the thermostability of the precursors to validate selected initial pyrolysis temperatures (500 and 700°C). C₆H₆ sorption lies mainly in the physisorption region for all adsorbents ensuring re-generation potential. PyF720 and PyF520 recorded the highest isosteric enthalpy of 64.4 kJ/mol and 48.7 kJ/mol respectively, despite the low degree of coverage of the latter. Thus, PyF515 and PyF720 demonstrated the potential for use as sustainable and cost effective adsorbents for benzene gas containment suitable for swing adsorption system.7 page(s

Variation in sooting characteristics and cetane number of diesel with the addition of a monoterpene biofuel, α-pinene

International audienceDiesel fuel combustion generates soot particles, which are harmful for human health and the environment. To reduce soot emission, various solutions are proposed in the literature such as the use of metal-additives in fuels, fuel blending with biofuels, and the use of diesel particulate filters. This study analyses the effect of the addition of a bicyclic monoterpene hydrocarbon biofuel, α-pinene to diesel in different proportions on the fuel cetane number, sooting propensity, and the physicochemical properties of soot nanoparticles. The addition of 10% α-pinene to diesel exhibited a synergistic effect on sooting tendency and reduced the threshold sooting index of diesel by 21%, even though α-pinene is an unsaturated hydrocarbon, and had a minimal impact on cetane number, which reduced from 63.5 for diesel to 61.5 for the blended fuel. The influence of α-pinene addition to diesel on soot nanostructural characteristics and reactivity is determined through different characterization approaches including HRTEM, TGA, XRD, SEM-EDX, and EELS. The results indicate that α-pinene addition to diesel imposes curvatures in soot nanostructure, creates relatively smaller fringes (PAHs) in soot, and reduces soot aromatic content to improve soot oxidation rate

Crude bioglycerol derived sulfur-doped carbon material for electrooxidation of bioglycerol and other alcohols

By 2030, most developing countries aim to produce affordable and clean energy in accordance with UN Sustainable Development Goals. Thus, there has been a surge of interest in biofuels such as biodiesel. However, as the production of biodiesel increases, so does the issue of excess bioglycerol, which is a by-product of the process with no large-scale applications. To address this, the cost-effective utilization of bioglycerol, for example, in direct bioglycerol fuel cells or to synthesize carbon-based materials, is necessary. This study focuses on exploring the potential of used cooking oil to produce crude bioglycerol and further utilizing it as a carbon and energy source. Crude glycerol-based sulfur-doped carbon materials (S-CGBC) with graphene oxide-like appearance were synthesized using an acid dehydration method. The synthesized carbon material was fully characterized and was further analyzed to determine its potential as support materials on nickel foam for glycerol electrooxidation reaction (GEOR) and crude bioglycerol electrooxidation reaction (BGEOR). S-CGBC demonstrated good catalytic activity and stability for both GEOR and BGEOR, with high peak current densities of 262 mA/cm2 and 272 mA/cm2 at 0.6 V vs Ag/AgCl for GEOR and BGEOR, respectively. The HPLC analysis revealed 78.3% glycerol after 15 hours of bulk electrolysis of 1 M glycerol. The results of this study highlight the potential of waste crude bioglycerol as a good source of energy as well as of carbon materials