Authors: Torkel E Loman, Yingbo Ma, Vasily Ilin...

We introduce Catalyst.jl, a flexible and feature-filled Julia library for modeling and high-performance simulation of chemical reaction networks (CRNs). Catalyst supports simulating stochastic chemical kinetics (jump process), chemical Langevin equation (stochastic differential equation), and reaction rate equation (ordinary differential equation) representations for CRNs. Through comprehensive benchmarks, we demonstrate that Catalyst simulation runtimes are often one to two orders of magnitude faster than other popular tools. More broadly, Catalyst acts as both a domain-specific language and an intermediate representation for symbolically encoding CRN models as Julia-native objects. This enables a pipeline of symbolically specifying, analyzing, and modifying CRNs; converting Catalyst models to symbolic representations of concrete mathematical models; and generating compiled code for numerical solvers. Leveraging ModelingToolkit.jl and Symbolics.jl, Catalyst models can be analyzed, simplified, and compiled into optimized representations for use in numerical solvers. Finally, we demonstrate Catalyst's broad extensibility and composability by highlighting how it can compose with a variety of Julia libraries, and how existing open-source biological modeling projects have extended its intermediate representation.

Topics: Algorithms; Stochastic Processes; Computer Simulation; Models, Theoretical; Models, Biological

PubMed: 37851697
DOI: 10.1371/journal.pcbi.1011530

Review

Authors: Graham J Hutchings

Catalysis is at the heart of many manufacturing processes and underpins provision of the goods and infrastructure necessary for the effective wellbeing of society; catalysis continues to play a key role in the manufacture of chemical intermediates and final products. There is a continuing need to design new effective catalysts especially with the drive toward using sustainable resources. The identification that gold is an exceptionally effective catalyst has paved the way for a new class of active heterogeneous and homogeneous catalysts for a broad range of reactions. As a heterogeneous catalyst gold is the most active catalyst for the oxidation of carbon monoxide at ambient temperature. It is also the most effective catalyst for the synthesis of vinyl chloride by acetylene hydrochlorination, and a gold catalyst has recently been commercialized in China for this reaction. In this outlook the nature of the active gold species for these two reactions will be explored.

PubMed: 30276242
DOI: 10.1021/acscentsci.8b00306

Review

Authors: Leslie Trigoura, Yalan Xing, Bhanu P S Chauhan...

In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have incorporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane-encapsulated novel metal nanoparticle-based catalysts, silica-copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic framework (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowledge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis.

PubMed: 34207751
DOI: 10.3390/molecules26123525

Review

Authors: Bubun Banerjee

Mother Nature needs to be protected from ever increasing chemical pollutions associated with synthetic organic processes. The fundamental challenge for today's methodologists is to make their protocols more environmentally benign and sustainable by avoiding the extensive use of hazardous reagents and solvents, harsh reaction conditions, and toxic metal catalysts. However, the people of the twenty-first century are well aware about the side effects of those hazardous substances used and generated by the chemical processes. As a result, the last decade has seen a tremendous outburst in modifying chemical processes to make them 'sustainable' for the betterment of our environment. Catalysts play a crucial role in organic synthesis and thus they find huge applications and uses. Scientists' continuously trying to modify the catalysts to reduce their toxicity level, but the most benign way is to design an organic reaction without catalyst(s), if possible. It is worthy to mention that the involvement of ultrasound in organic synthesis is sometimes fulfilling this goal. In many occasions the applications of ultrasound can avoid the use of catalysts in organic reactions. Such beneficial features as a whole have motivated the organic chemists to apply ultrasonic irradiation in more heights and as a results, in recent past, there were immense applications of ultrasound in organic reactions for the synthesis of diverse organic scaffolds under catalyst-free condition. The present review summarizes the latest developments on ultrasound assisted catalyst-free organic synthesis reported so far.

PubMed: 27771266
DOI: 10.1016/j.ultsonch.2016.09.023

Review

Authors: Waheed A Rasaq, Charles Odilichukwu R Okpala, Chinenye Adaobi Igwegbe...

The research impact of catalysts on the hydrothermal carbonization (HTC) process remains an ongoing debate, especially regarding the quest to enhance biomass conversion into fuels and chemicals, which requires diverse catalysts to optimize bio-oil utilization. Comprehensive insights and standardized analytical methodologies are crucial for understanding HTC's potential benefits in terms of biomass conversion stages. This review seeks to understand how catalysts enhance the HTC of biomass for liquid fuel and hydrochar production, drawing from the following key sections: (a) catalyst types applied in HTC processes; (b) biochar functionality as a potential catalyst; (c) catalysts increasing the success of HTC process; and (d) catalyst's effect on the morphological and textural character of hydrochar. The performance of activated carbon would greatly increase via catalyst action, which would progress the degree of carbonization and surface modification, alongside key heteroatoms. As catalytic HTC technology advances, producing carbon materials for thermochemical activities will become more cost-effective, considering the ever-growing demands for high-performance thermochemical technologies.

PubMed: 38893844
DOI: 10.3390/ma17112579

Review

Authors: Iqra R Hamdani, Adeel Ahmad, Haleema M Chulliyil...

The global initiatives on sustainable and green energy resources as well as large methane reserves have encouraged more research to convert methane to hydrogen. Catalytic decomposition of methane (CDM) is one optimistic route to generate clean hydrogen and value-added carbon without the emission of harmful greenhouse gases, typically known as blue hydrogen. This Review begins with an attempt to understand fundamentals of a CDM process in terms of thermodynamics and the prerequisite characteristics of the catalyst materials. In-depth understanding of rate-determining steps of the heterogeneous catalytic reaction taking place over the catalyst surfaces is crucial for the development of novel catalysts and process conditions for a successful CDM process. The design of state-of-the-art catalysts through both computational and experimental optimizations is the need of hour, as it largely governs the economy of the process. Recent mono- and bimetallic supported and unsupported materials used in CDM process have been highlighted and classified based on their performances under specific reaction conditions, with an understanding of their advantages and limitations. Metal oxides and zeolites have shown interesting performance as support materials for Fe- and Ni-based catalysts, especially in the presence of promoters, by developing strong metal-support interactions or by enhancing the carbon diffusion rates. Carbonaceous catalysts exhibit lower conversions without metal active species and largely result in the formation of amorphous carbon. However, the stability of carbon catalysts is better than that of metal oxides at higher temperatures, and the overall performance depends on the operating conditions, catalyst properties, and reactor configurations. Although efforts to summarize the state-of-art have been reported in literature, they lack systematic analysis on the development of stable and commercially appealing CDM technology. In this work, carbon catalysts are seen as promising futuristic pathways for sustained H production and high yields of value-added carbon nanomaterials. The influence of the carbon source, particle size, surface area, and active sites on the activity of carbon materials as catalysts and support templates has been demonstrated. Additionally, the catalyst deactivation process has been discussed, and different regeneration techniques have been evaluated. Recent studies on theoretical models towards better performance have been summarized, and future prospects for novel CDM catalyst development have been recommended.

PubMed: 37599913
DOI: 10.1021/acsomega.3c01936

Authors: Yusuf Osman Donar, Ali Tolga Ünalan, Samed Ergenekon...

In this study, effects of TiO and ZnO nanometal oxides on cellulose pyrolysis have been investigated. Both catalysts have been synthesized via hydrothermal method and characterized by using different techniques. Catalytic and catalyst-free experiments were carried out so as to identify the catalytic abilities of synthesized nanoparticles. Catalyst-free experiments were carried out at 500, 600, and 700 °C in order to determine the optimal condition for pyrolysis and it was found as 700 °C. Optimum catalyst ratio for cellulose pyrolysis was found as 5% (w/w) for both TiO and ZnO catalysts. GC-MS and micro-GC analyses were conducted in order to examine the catalytic properties of synthesized nanoparticles and illuminate the content of pyrolytic oil and gaseous products. Results showed that maximum gas yield was observed at 700 °C in the presence of 5% TiO. Maximum activity for both catalysts was observed at 700 °C and the char yield was significantly decreased in each catalytic experiment at specified temperatures, compared to catalyst-free experiments. Both nanoparticles catalyzed the dehydration and decarbonylation reactions and significantly increased the amount of furan derivatives, especially furanic aldehydes.

PubMed: 37720864
DOI: 10.55730/1300-0527.3522

Review

Authors: Wendy L Williams, Lingyu Zeng, Tobias Gensch...

Organic chemistry is replete with complex relationships: for example, how a reactant's structure relates to the resulting product formed; how reaction conditions relate to yield; how a catalyst's structure relates to enantioselectivity. Questions like these are at the foundation of understanding reactivity and developing novel and improved reactions. An approach to probing these questions that is both longstanding and contemporary is data-driven modeling. Here, we provide a synopsis of the history of data-driven modeling in organic chemistry and the terms used to describe these endeavors. We include a timeline of the steps that led to its current state. The case studies included highlight how, as a community, we have advanced physical organic chemistry tools with the aid of computers and data to augment the intuition of expert chemists and to facilitate the prediction of structure-activity and structure-property relationships.

PubMed: 34729406
DOI: 10.1021/acscentsci.1c00535

Silica supported lanthanum trifluoroacetate and trichloroacetate as an efficient and reusable water compatible Lewis acid catalyst for synthesis of 2,4,5-triarylimidazoles a solvent-free green approach.

Authors: Dnyaneshwar Purushottam Gholap, Ramdas Huse, Sudarshan Dipake...

In the present research article, we have developed solid heterogenous silica supported lanthanum trifluoroacetate and trichloroacetate as green Lewis acid catalysts. These catalysts were synthesized by a novel, simple, cheap, clean, and environment friendly method. The physicochemical properties of the prepared catalysts were well studied and characterized by sophisticated spectroscopic techniques such as FTIR, TGA, XRD, EDX, SEM, TEM and BET analysis. The catalyst was utilized in the synthesis of arylimidazole derivatives green protocols under solvent-free conditions at 70 °C with a higher yield, mild reaction conditions and a short reaction time. The catalyst works superiorly in water as well as in various organic solvents as a reusable and easily recoverable catalyst.

PubMed: 36712612
DOI: 10.1039/d2ra07021a

Review

Authors: Bo Zhang, Joost N H Reek

Supramolecular approaches are increasingly used in the development of homogeneous catalysts and they also provide interesting new tools for the recycling of metal-based catalysts. Various non-covalent interactions have been utilized for the immobilization homogeneous catalysts on soluble and insoluble support. By non-covalent anchoring the supported catalysts obtained can be recovered via (nano-) filtration or such catalytic materials can be used in continuous flow reactors. Specific benefits from the reversibility of catalyst immobilization by non-covalent interactions include the possibility to re-functionalize the support material and the use as "boomerang" type catalyst systems in which the catalyst is captured after a homogeneous reaction. In addition, new reactor design with implemented recycling strategies becomes possible, such as a reverse-flow adsorption reactor (RFA) that combines a homogeneous reactor with selective catalyst adsorption/desorpion. Next to these non-covalent immobilization strategies, supramolecular chemistry can also be used to generate the support, for example by generation of self-assembled gels with catalytic function. Although the stability is a challenging issue, some self-assembled gel materials have been successfully utilized as reusable heterogeneous catalysts. In addition, catalytically active coordination cages, which are frequently used to achieve specific activity or selectivity, can be bound to support by ionic interactions or can be prepared in structured solid materials. These new heterogenized cage materials also have been used successfully as recyclable catalysts.

PubMed: 34606169
DOI: 10.1002/asia.202100968