589-90-2Relevant academic research and scientific papers
Recovery of Arenes from Polyethylene Terephthalate (PET) over a Co/TiO2 Catalyst
Hongkailers, Surachet,Jing, Yaxuan,Wang, Yanqin,Hinchiranan, Napida,Yan, Ning
, p. 4330 - 4339 (2021/09/03)
Upcycling of spent plastics has become a more emergent topic than ever before due to the rapid generation of plastic waste associated with the change of lifestyles of the human society. Polyethylene terephthalate (PET) is a major aromatic plastic and herein, the conversion of PET back into arenes was demonstrated in a one-pot reaction combining depolymerization and hydrodeoxygenation (HDO) over a Co/TiO2 catalyst. The effectiveness of the Co/TiO2 catalyst in HDO and the underlining reaction pathway were established using the PET monomer terephthalic acid (TPA) as the substrate. Quantitative TPA conversion together with 75.2 mol% xylene and toluene selectivity under 30 bar initial H2 pressure at 340 °C was achieved after 4 h reaction. More encouragingly, the catalyst induced both depolymerization and HDO reaction via C?O bond cleavage when PET was used as a substrate. 78.9 mol% arenes (toluene and xylene) was obtained under optimized conditions.
Towards the Circular Economy: Converting Aromatic Plastic Waste Back to Arenes over a Ru/Nb2O5 Catalyst
Jing, Yaxuan,Wang, Yanqin,Furukawa, Shinya,Xia, Jie,Sun, Chengyang,Hülsey, Max J.,Wang, Haifeng,Guo, Yong,Liu, Xiaohui,Yan, Ning
supporting information, p. 5527 - 5535 (2021/02/05)
The upgrading of plastic waste is one of the grand challenges for the 21st century owing to its disruptive impact on the environment. Here, we show the first example of the upgrading of various aromatic plastic wastes with C?O and/or C?C linkages to arenes (75–85 % yield) via catalytic hydrogenolysis over a Ru/Nb2O5 catalyst. This catalyst not only allows the selective conversion of single-component aromatic plastic, and more importantly, enables the simultaneous conversion of a mixture of aromatic plastic to arenes. The excellent performance is attributed to unique features including: (1) the small sized Ru clusters on Nb2O5, which prevent the adsorption of aromatic ring and its hydrogenation; (2) the strong oxygen affinity of NbOx species for C?O bond activation and Br?nsted acid sites for C?C bond activation. This study offers a catalytic path to integrate aromatic plastic waste back into the supply chain of plastic production under the context of circular economy.
One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
Coeck, Robin,De Vos, Dirk E.
supporting information, p. 5105 - 5114 (2020/08/25)
The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
Catalytic reduction of aromatic ring in aqueous medium
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Page/Page column 10-11; 17, (2020/05/04)
A method of reducing an aromatic ring under relatively mild condition using sub-nano particles of a transition metal supported on super paramagnetic iron oxide nanoparticles (SPIONs). The catalyst is efficient for catalyzing the reduction of both carbocyclic and heterocyclic compound. In compound comprising both carbocyclic and heterocyclic aromatic rings, the catalyst displays high regioselectivity for the heterocyclic ring.
One-pot dual catalysis for the hydrogenation of heteroarenes and arenes
Chatterjee, Basujit,Kalsi, Deepti,Kaithal, Akash,Bordet, Alexis,Leitner, Walter,Gunanathan, Chidambaram
, p. 5163 - 5170 (2020/09/07)
A simple dinuclear monohydrido bridged ruthenium complex [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] acts as an efficient and selective catalyst for the hydrogenation of various heteroarenes and arenes. The nature of the catalytically active species was investigated using a combination of techniques including in situ reaction monitoring, kinetic studies, quantitative poisoning experiments and electron microscopy, evidencing a dual reactivity. The results suggest that the hydrogenation of heteroarenes proceeds via molecular catalysis. In particular, monitoring the reaction progress by NMR spectroscopy indicates that [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] is transformed into monomeric ruthenium intermediates, which upon subsequent activation of dihydrogen and hydride transfer accomplish the hydrogenation of heteroarenes under homogeneous conditions. In contrast, carbocyclic aryl motifs are hydrogenated via a heterogeneous pathway, by in situ generated ruthenium nanoparticles. Remarkably, these hydrogenation reactions can be performed using molecular hydrogen under solvent-free conditions or with 1,4-dioxane, and thus give access to a broad range of saturated heterocycles and carbocycles while generating no waste.
Effects of steam on toluene hydrogenation over a Ni catalyst
Atsumi, Ryosuke,Kobayashi, Keisuke,Xieli, Cui,Nanba, Tetsuya,Matsumoto, Hideyuki,Matsuda, Keigo,Tsujimura, Taku
, (2019/12/23)
The catalytic toluene hydrogenation over Ni/SiO2 was carried out using H2 or a H2/H2O mixture. The toluene conversion and MCH selectivity were evaluated under partial steam pressures 0?10 kPa, at H2/t
Mesoporous Silica Doped with Dysprosium and Modified with Nickel: A Highly Efficient and Heterogeneous Catalyst for the Hydrogenation of Benzene, Ethylbenzene and Xylenes
Shafigulin,Filippova,Shmelev,Bulanova
, p. 916 - 928 (2019/02/14)
The catalytic activity of synthesized by the template method mesoporous silica doped with dysprosium and modified with nickel (Dy-Ni/MPS) in the hydrogenation of benzene, ethylbenzene and xylenes has been studied. The catalyst is characterized by various techniques such as TEM, SEM, BET, XRD, ICP, XRF analyses. It is shown that the presence of dysprosium in the MPS structure increases the activity of the catalyst. The catalytic activity of the catalyst (Dy-Ni/MPS) has been explored in hydrogenation reaction of benzene derivatives with excellent conversion (96–100%) at low pressure. Graphical Abstract: [Figure not available: see fulltext.].
Synthesis of gasoline and jet fuel range cycloalkanes and aromatics from poly(ethylene terephthalate) waste
Tang, Hao,Li, Ning,Li, Guangyi,Wang, Aiqin,Cong, Yu,Xu, Guoliang,Wang, Xiaodong,Zhang, Tao
supporting information, p. 2709 - 2719 (2019/06/03)
For the first time, gasoline and jet fuel range C7-C8 cycloalkanes and aromatics were selectively synthesized by the alcoholysis of poly(ethylene terephthalate) (PET) waste, followed by solvent-free hydrogenation and hydrodeoxygenation (HDO). It was found that methanol is highly reactive for the alcoholysis of PET waste. In the absence of any catalyst, a high yield of dimethyl terephthalate (97.3%) was achieved under mild conditions (473 K, 3.5 h). Dimethyl terephthalate exists as a solid and can be automatically separated from methanol with a decrease in temperature. Subsequently, dimethyl terephthalate was liquefied to dimethyl cyclohexane-1,4-dicarboxylate by hydrogenation over noble metal catalysts. Among the investigated catalysts, Pt/C exhibited the highest activity. Finally, the dimethyl cyclohexane-1,4-dicarboxylate as obtained was further hydrodeoxygenated to C7-C8 cycloalkanes and aromatics that can be used as gasoline or additives to improve the densities (or volumetric heat value) and sealabilities of current bio-jet fuels. Bimetallic Ru-Cu/SiO2 was found to be a promising HDO catalyst. According to the characterization results, the excellent HDO performance of Ru-Cu/SiO2 can be explained by the formation of smaller Ru-Cu alloy particles during the catalyst preparation. In real applications, dimethyl cyclohexane-1,4-dicarboxylate can also be simultaneously hydrodeoxygenated with biomass derived oxygenates to produce jet fuel with a suitable content of cycloalkanes and aromatics.
Catalytic hydrogenation products of aromatic and aliphatic dicarboxylic acids
Shinde, Sunil B.,Deshpande, Raj M.
, p. 1137 - 1142 (2019/04/05)
Hydrogenation of aromatic dicarboxylic acids gave 100 % selectivity to respective cyclohexane dicarboxylic acid with 5 % Pd/C catalyst. 5 % Ru/C catalyst was observed to give over hydrogenation products at 493 K and at lower temperature (453 K) the selectivity for cyclohexane dicarboxylic acids was increased. Hydrogenation of phthalic acid with Ru-Sn/Al2O3 catalyst was observed to give phthalide instead of 1,2-benzene dimethanol or 2-hydroxy methyl benzoic acid. Ru-Sn/Al2O3 catalyst selectively hydrogenated the carboxylic group of cyclohexane dicarboxylic acids to give cyclohexane dimethanol. Use of proper catalysts and reaction conditions resulted in desired products.
Titanium(III)-Oxo Clusters in a Metal-Organic Framework Support Single-Site Co(II)-Hydride Catalysts for Arene Hydrogenation
Ji, Pengfei,Song, Yang,Drake, Tasha,Veroneau, Samuel S.,Lin, Zekai,Pan, Xiandao,Lin, Wenbin
, p. 433 - 440 (2018/01/17)
Titania (TiO2) is widely used in the chemical industry as an efficacious catalyst support, benefiting from its unique strong metal-support interaction. Many proposals have been made to rationalize this effect at the macroscopic level, yet the underlying molecular mechanism is not understood due to the presence of multiple catalytic species on the TiO2 surface. This challenge can be addressed with metal-organic frameworks (MOFs) featuring well-defined metal oxo/hydroxo clusters for supporting single-site catalysts. Herein we report that the Ti8(μ2-O)8(μ2-OH)4 node of the Ti-BDC MOF (MIL-125) provides a single-site model of the classical TiO2 support to enable CoII-hydride-catalyzed arene hydrogenation. The catalytic activity of the supported CoII-hydride is strongly dependent on the reduction of the Ti-oxo cluster, definitively proving the pivotal role of TiIII in the performance of the supported catalyst. This work thus provides a molecularly precise model of Ti-oxo clusters for understating the strong metal-support interaction of TiO2-supported heterogeneous catalysts.
