Development Of Catalytic Processes Research Articles

Hydrodeoxygenation of Oxygen-Containing Aromatic Plastic Wastes into Cycloalkanes and Aromatics.

Chemical recycling and upcycling offer promising approaches for the management of plastic wastes. Hydrodeoxygenation (HDO) is one of the appealing ways for conversion of oxygen-containing plastic wastes, including polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonate (PC), polyphenyl ether (PPO), and polyether ether ketone (PEEK), into cyclic alkanes and aromatics in high yields under mild reaction conditions. The challenge lies in achieving C-O activation while preserving C-C bonds. In this review, we highlight the recent advancements in catalytic strategies and catalysts for the conversion of these oxygen-containing plastic wastes into cycloalkanes and aromatics. The reaction systems, including multi-step routes, direct HDO and transfer HDO methods, are exemplified. The design and performance of HDO catalysts are systematically summarized and compared. We comprehensively discuss the functions of the catalysts' components, reaction pathway and mechanism to gain insights into the HDO process for efficient valorization of oxygen-containing plastic wastes. Finally, we provide perspectives for this field, with specific emphasis on the non-noble metal catalyst design, selectivity control, reaction network and mechanism studies, mixed plastic wastes management and product functionalization. We anticipate that this review will inspire innovations on the catalytic process development and rational catalyst design for the HDO of oxygen-containing aromatic plastics to establish a low-emission circular economy.

Catalytic Synthesis of Carbonyl Compounds Using Acyl Fluorides, Carbamoyl Fluorides, and Fluoroformates: An Overview

AbstractAcyl fluorides, carbamoyl fluorides and fluoroformates have been employed as efficient reagents in a number of organic syntheses. Their application in catalytic transformations, however, began to be explored in the early 2000s. Recently, these reagents have increasingly gained attention owing to their unique reactivity in diverse catalytic systems. This review aims to overview the advancements in the development of catalytic processes, including transition‐metal catalysis, organocatalysis, and cooperative NHC/photoredox catalysis, where these organofluorine compounds are employed as acyl, carbamoyl, and ester group donors.

Development of Catalytic Processes for the Production of Olefins

Development of Catalytic Processes for the Production of Olefins

Lignin-Based Catalysts for C-C Bond-Forming Reactions.

Carbon-carbon (C-C) bond formation is the key reaction in organic synthesis to construct the carbon framework of organic molecules. The continuous shift of science and technology toward eco-friendly and sustainable resources and processes has stimulated the development of catalytic processes for C-C bond formation based on the use of renewable resources. In this context, and among other biopolymer-based materials, lignin has attracted scientific attention in the field of catalysis during the last decade, either through its acid form or as a support for metal ions and metal nanoparticles that drive the catalytic activity. Its heterogeneous nature, as well as its facile preparation and low cost, provide competitive advantages over other homogeneous catalysts. In this review, we have summarized a variety of C-C formation reactions, such as condensations, Michael additions of indoles, and Pd-mediated cross-coupling reactions that were successfully carried out in the presence of lignin-based catalysts. These examples also involve the successful recovery and reuse of the catalyst after the reaction.

Hierarchically organized metal supported carbon catalysts for C-C bond forming reactions

The preparation of heterogeneous catalysts is decisive to the development of catalytic processes that are environmentally acceptable. Therefore, the methodology used in the preparation of such catalysts is a key factor in the development of high catalytic activity and with concern to environmental value. Herein, we report the design of catalysts by dispersing nanoparticles of cobalt oxide (Co3O4) on micrometric supports of zinc oxide (ZnO) and activated carbon (AC) using a fast and green methodology free of waste and solvents and with a low-energy consumption. In particular, the partial reaction that takes place, at room temperature, between both metal oxides and between these oxides and AC, due to proximity and diffusion effects of the corresponding materials, results in the formation of different interfaces (ZnCo, ZnAC, CoAC Co-Co). Specifically, such interfaces are new reactive surfaces that lead to very interesting and innovative properties. Thus, depending on its application, it is possible to control and modify the catalytic properties (activity / conversion / selectivity) of a solid by tuning surface and interface. This fact is proved in the model reaction of Knoevenagel condensation between aldehydes and malonic esters. Therefore, our results prove that controlling the interfaces is a feasible way to achieve in the Knoevenagel condensation, which is a reaction widely used in the formation of C–C bonds for the organic synthesis of important intermediates and final products.

Molybdenum, Vanadium, and Tungsten-Based Catalysts for Sustainable (ep)Oxidation.

This article gives an overview of the research activity of the LAC2 team at LCC developed at Castres in the field of sustainable chemistry with an emphasis on the collaboration with a research team from the University of Zagreb, Faculty of Science, Croatia. The work is situated within the context of sustainable chemistry for the development of catalytic processes. Those processes imply molecular complexes containing oxido-molybdenum, -vanadium, -tungsten or simple polyoxometalates (POMs) as catalysts for organic solvent-free epoxidation. The studies considered first the influence of the nature of complexes (and related ligands) on the reactivity (assessing mechanisms through DFT calculations) with model substrates. From those model processes, the work has been enlarged to the valorization of biomass resources. A part concerns the activity on vanadium chemistry and the final part concerns the use of POMs as catalysts, from molecular to grafted catalysts, (ep)oxidizing substrates from fossil and biomass resources.

The CREC Fluidized Riser Simulator a Unique Tool for Catalytic Process Development

The CREC Riser Simulator is a mini-fluidized bench scale unit invented and implemented in 1992, at the CREC (Chemical Reactor Engineering Centre), University of Western Ontario The CREC Riser Simulator can be operated at short reaction times, in the 3 s to 20 s range. The present review describes and evaluates the original basic concept of the 1992-CREC Riser Simulator Unit, and the improved design of the 2019-CREC Riser Simulator. Both the initial and the enhanced units are specially engineered to allow the rigorous assessment of both catalyst performance and catalytic reaction kinetics. Kinetic parameters of relatively simple and accurate mathematical models can be calculated using experimental data from the CREC Riser Simulator. Since its inception in 1992, the CREC Riser Simulator has been licensed to and manufactured for a significant number of universities and companies around the world. Several examples of scenarios where the CREC Riser Simulator can be employed to develop fluidized bed catalytic and heterogeneous reactor simulations are reported in this review. Among others, they include (a) hydrocarbon catalytic cracking, (b) the catalytic conversion of tar derived biomass chemical species, (c) steam and dry catalytic methane reforming, (d) the catalytic oxydehydrogenation of light paraffins, (e) the catalytic desulfurization of gasoline, and (f) biomass derived syngas combustion via chemical looping. In this review, special emphasis is given to the application of the CREC Riser Simulator to TIPB (tri-iso-propyl-benzene) catalytic cracking and the light paraffins catalytic oxydehydrogenation (PODH).

Chiral Amines via Enantioselective π-Allyliridium-C,O-Benzoate-Catalyzed Allylic Alkylation: Student Training via Industrial-Academic Collaboration.

Cyclometalated π-allyliridium-C,O-benzoate complexes discovered in the Krische laboratory display unique amphiphilic properties, catalyzing both nucleophilic carbonyl allylation and electrophilic allylation of diverse amines as well as nitronates. Given the importance of chiral amines in FDA-approved small-molecule drugs, a collaboration with medicinal chemists at Genentech that included on-site graduate student internships was undertaken to explore and expand the scope of π-allyliridium-C,O-benzoate-catalyzed allylic amination and related processes. As described in this Account, our collective experimental studies have unlocked asymmetric allylic aminations of exceptionally broad utility and scope. Specifically, using racemic branched alkyl-substituted allylic acetate proelectrophiles, primary and secondary aliphatic or aromatic amines, including indoles, engage in highly regio- and enantioselective allylic amination. Additionally, unactivated nitronates were found to be competent nucleophilic partners for regio- and enantioselective allylic alkylation, enabling entry to β-stereogenic α-quaternary primary amines. Notably, these π-allyliridium-C,O-benzoate-catalyzed allylic substitutions, which display complete branched regioselectivity in reactions of alkyl-substituted allyl electrophiles, complement the scope of corresponding iridium phosphoramidite-catalyzed allylic aminations, which require aryl-substituted allyl electrophiles to promote high levels of branched regioselectivity. Computational, kinetic, ESI-CID-MS, and isotopic labeling studies were undertaken to understand the mechanism of these processes, including the origins of regio- and enantioselectivity. Isotopic labeling studies suggest that C-N bond formation occurs through outer-sphere addition to the π-allyl. DFT calculations corroborate C-N bond formation via outer-sphere addition and suggest that early transition states and distinct trans effects of diastereomeric chiral-at-iridium π-allyl complexes render the reaction less sensitive to steric effects, accounting for complete levels of branched regioselectivity in reactions of hindered amine and nitronate nucleophiles. Reaction progress kinetic analysis (RPKA) reveals a zero-order dependence on allyl acetate, a first-order dependence on the catalyst, and a fractional-order dependence on the amine. As corroborated by ESI-CID-MS analysis, the 0.4 kinetic order dependence on the amine may reflect the intervention of cesium-bridged amine dimers, which dissociate to form monomeric cesium amide nucleophiles. Hence, the requirement of cesium carbonate (vs lower alkali metal carbonates) in these processes may reside in cesium's capacity for Lewis acid-enhanced Brønsted acidification of the amine pronucleophile. Beyond the development of catalytic processes for the synthesis of novel chiral amines, the present research was conducted by graduate students who benefited from career development experiences associated with training in both academic and industrial laboratories.

Catalytic process development strategies for conversion of propane to liquid hydrocarbons

The temperature effect on propane dehydroaromatization pathways on the PtZn/SiO2 +ZSM-5 bifunctional catalysts is investigated to develop strategies for propane conversion to valuable liquid hydrocarbons. At high temperature (550 ℃), high dehydrogenation rates and lower monomolecular cracking rates are required to minimize methane formation, leading to primarily propene and BTX (benzene, toluene, and xylenes). By recycling propene in the propane conversion range of 30–45%, > 80% BTX yields is likely achievable at full recycle. At mid temperature (400–450 ℃), the product has high selectivity to gasoline-blending hydrocarbons (butanes, C5+ hydrocarbons, toluene, and xylenes) at 15–25% propane conversions because dehydrogenation rates are moderately high, and oligomerization is more favored than cracking. At low temperature (350 ℃), ~25% propane conversion is achieved and has high selectivity (~60%) to butanes, but the propane conversion rates are likely too low to be practical. While methane formation by monomolecular cracking limits liquid yields at high reaction temperature, hydrogen co-produced at high propane conversions saturates light olefins to make undesired ethane, which becomes major yield loss reaction on the PtZn/SiO2 +ZSM-5 at mid and low temperatures.

Catalytic Process Development of Bio-BTX from Lignocellulose Derived Product: Preliminary Study Using Transition Metal Catalysts

Lately, the increase in biofuel production has simultaneously led to lignocellulose material disposal activities. As a waste produced by the biofuel industry, lignocellulose materials are not utilized fully yet due to their complex polymeric structure. As one compound of lignocellulose, lignin possesses the lowest economic value due to its recalcitrant nature. In this work, guaiacol as one of monomeric substance originated from lignin is used as a representative molecule to be valorized due to the existence of both hydroxyl and methoxy moiety groups in it. One important reaction of lignin monomeric substance (phenolic compounds) valorization is oxygen removal. Aromatic substances such as Benzene and Toluene are produced through oxygen removal from the guaiacol molecule. Hydrodeoxygenation of guaiacol is aimed to remove oxygen atoms from it. Though conventionally hydrogen for the Hydrodeoxygenation process is supplied by external molecular hydrogen, in this work it is supplied from hydrogen atom abstraction of methylcyclohexane. Therefore, in a one-pot catalytic reaction system, methylcyclohexane dehydrogenation is the sole hydrogen provider for subsequent hydrodeoxygenation of guaiacol and this novel concept of a circular hydrogen economy has been proven its feasibility through heterogeneous catalytic reaction schemes conducted in this work. Metal supported on zeolite beta is selected as heterogeneous catalysts to evaluate the feasibility of one-pot hydrodeoxygenation and dehydrogenation reaction. Of every catalytic reaction attempt, multiple products consist of alkylated phenol, phenol itself, and toluene are observed proofing the feasibility of this concept. Possible interaction of catalyst surface acidity and metal contents are also probed through the distribution of byproducts. Overall, sequential dehydrogenation and hydrodeoxygenation have been proven through a catalytic reaction catalyzed by metal-supported zeolite beta catalyst and this work can potentially pave the way for further application.

Coupling of Alternating Current to Transition-Metal Catalysis: Examples of Nickel-Catalyzed Cross-Coupling

The coupling of transition-metal to photoredox catalytic cycles through single-electron transfer steps has become a powerful tool in the development of catalytic processes. In this work, we demonstrated that transition-metal catalysis can be coupled to alternating current (AC) through electron transfer steps that occur periodically at the same electrode. AC-assisted Ni-catalyzed amination, etherification, and esterification of aromatic bromides showed higher yields and selectivity compared to that observed in the control experiments with direct current. Our mechanistic studies suggested the importance of both reduction and oxidation processes in the maintenance of the AC-assisted catalytic reactions. As described in presented examples, the AC assistance should be well-suited for catalytic cycles involving reductive elimination or oxidative addition as a limiting step.

Expanding the Color Space in the Two-Color Heterogeneous Photocatalysis of Ullmann C–C Coupling Reactions

The Ullmann reaction can be heterogeneously photocatalyzed by UV excitation of Pd@TiO2. While a similar dose of visible light does not initiate the reaction, combination with UV light enhances activity and selectivity toward cross-combination products. The reaction involves photoresponsive intermediates, likely associated with the catalyst, where Pd nanostructures can absorb visible radiation and TiO2, the UV component. Hence, a single hybrid-photoresponsive material can have different reactivity upon two-wavelength irradiation enabling direct tuning of yields and selectivity. This color-space expansion promises unprecedented uses in organic chemistry, where improvement in catalytic activity and selectivity will impact the development of catalytic processes with long-term multicycle performance.

The Development and Application of an Evolutionary Algorithm for the Determination of Kinetic Parameters in Automotive Aftertreatment Models

Accurate mathematical models are an essential tool in the development of aftertreatment systems, as they can provide detailed information on the impact of design changes while simultaneously reducing development costs and the time between the initiation and completion of a catalytic process development. Identifying the set of kinetic parameters that achieves a perceived acceptable level of accuracy may require significant time and effort. Optimisation techniques can be used to speed up the tuning process; however, these techniques can require a large computation time, and may not produce a satisfactory answer. This invariably leads to questioning regarding the accuracy of such automated approaches. In this paper, the performance of a number of optimisation algorithms including a GA, nPSO and a hybrid algorithm has been explored with respect to their applicability to kinetic parameters optimisation in the context of aftertreatment modelling. The focus is therefore on the assessment of the optimisers’ performance, rather than the characterisation of catalytic reactions. The different algorithms were applied to the optimisation of parameters in a number of mathematical functions and theoretical aftertreatment systems. The optimisation algorithms were tested on theoretical aftertreatment systems since these have known absolute solutions thereby allowing the optimisers’ performance to be assessed in the absence of any other external source of inaccuracy such as model structure and experimental error. The results obtained demonstrate that such optimisation approaches facilitate the determination of kinetic parameters with suitable accuracy. The proposed hybrid optimisation algorithm achieved excellent performance in considerably shorter computation time than the GA or nPSO optimisers.

First-Principles Kinetic Study on the Effect of the Zeolite Framework on 1-Butanol Dehydration

Understanding the role of zeolite topology in defining its catalytic performance is of prime importance for the development of catalytic processes. Herein, a first-principles-based microkinetic study of 1-butanol dehydration is used to illustrate the effect of different zeolites (i.e., H-FAU, H-ZSM-5, H-ZSM-22, and H-FER) on the dehydration activity and product selectivity. Under identical reaction conditions, microkinetic simulations show significant variation in dehydration rates and butene/ether selectivity profiles within the different zeolites. H-ZSM-5 has the highest catalytic activity, whereas H-FAU and H-FER exhibit a higher butene selectivity. In the large pore H-FAU, the weaker dispersive stabilization of the dimer makes the butene formation by monomolecular direct dehydration via a concerted anti elimination compete with di-n-butyl ether formation. In H-FER, steric constraints due to partial confinement of the protonated di-n-butyl ether in the 8-MR channel decrease its stability, favoring its ...

Palladium-mediated borylation of pentafluorosulfanyl functionalized compounds: the crucial role of metal fluorido complexes.

Stoichiometric reactions of SF5 functionalized bromo or iodo aromatics at [Pd(PiPr3)2] (1) led to the oxidative addition products 3, 5 and 7. They were converted into their corresponding palladium fluorido complexes, which reacted readily with bis(pinacolato)diboron (B2pin2) to give the borylated SF5 aromatic compounds. Based on these studies a catalytic borylation of SF5 organyls was developed.

ChemInform Abstract: The Yin and Yang in the Development of Catalytic Processes: Catalysis Research and Reaction Engineering

AbstractReview: [interplay of catalyst chemistry and reaction engineering for processes such as the sulfuric acid production, ammonia synthesis, methanol synthesis, fluid catalytic cracking, and direct epoxidation of propylene at BASF; 106 refs.

The yin and yang in the development of catalytic processes: catalysis research and reaction engineering.

For the implementation of commercial catalytic processes, catalyst development and reactor design and engineering need to go hand-in-hand. As both fields are mutually interdependent, a co-evolution of catalysts and chemical reactors has historically been the right path towards successful, large-scale technologies. Over the 150 years of its existence, the contributions of BASF to the development of several commercial catalytic processes constitute perfect illustrations of this necessary and synergetic interplay between catalyst science and reactor engineering.

Catalytic process development for renewable materials

Catalytic process development for renewable materials

Modern Trends in Catalyst and Process Design for Alkyne Hydrogenations

This review provides an overview of the recent achievements in catalytic process development for alkyne hydrogenations. It underlines the necessity of simultaneous optimization over different length scales from molecular/nanoscale of active phase, up-to macro-scale of catalytic reactor design. One case study, the hydrogenation of 2-methyl-3-butyn-2-ol, is analyzed in detail to illustrate the practical application of this approach. Finally, it presents the personal view of the authors concerning the new trends and paths available in the field.

New eco-friendly animal bone meal catalysts for preparation of chalcones and aza-Michael adducts

Two efficient reactions were successfully carried out using Animal Bone Meal (ABM) and potassium fluoride or sodium nitrate doped ABMs as new heterogeneous catalysts under very mild conditions. After preparation and characterization of the catalysts, we first report their use in a simple and convenient synthesis of various chalcones by Claisen–Schmidt condensation and then in an aza-Michael addition involving several synthesized chalcones with aromatic amines. All the reactions were carried out at room temperature in methanol; the chalcone synthesis was also achieved in water environment under microwave irradiation. Doping ABM enhances the rate and yield at each reaction. Catalytic activities are discussed and the ability to re-use the ABM is demonstrated.ResultsFor Claisen–Schmidt the use of ABM alone, yields never exceeded 17%. In each entry, KF/ABM and NaNO3/ABM (79-97%) gave higher yields than using ABM alone under thermic condition. Also the reaction proceeded under microwave irradiation in good yields (72-94% for KF/ABM and 81-97% for NaNO3/ABM) and high purity. For aza-Michael addition the use of ABM doped with KF or NaNO3 increased the catalytic activity remarkably. The very high yields could be noted (84-95% for KF/ABM and 81-94% for NaNO3/ABM).ConclusionThe present method is an efficient and selective procedure for the synthesis of chalcones an aza-Michael adducts. The ABM and doped ABMs are a new, inexpensive and attractive solid supports which can contribute to the development of catalytic processes and reduced environmental problems.