Development Of Chemical Processes Research Articles

Life Cycle Cost Analysis for Decision Support in Chemical Process Development

AbstractDie Notwendigkeit umweltfreundlicher Prozesse als entscheidendes Merkmal der Wettbewerbsfähigkeit steht zunehmend im Fokus der chemischen Industrie. Grundlage für Entscheidungsprozesse bei der Entwicklung derartiger Prozesse können Ökobilanzanalysen bieten. Neue Technologien werden sich jedoch nur dann etablieren können, wenn sie auch zu kosteneffizienten Produktionsprozessen führen. Lebenszykluskostenanalysen bieten eine geeignete methodische Grundlage, die kostenseitige Bewertung alternativer Optionen der Prozessentwicklung mit ökologischen Entscheidungskriterien zu koppeln, wobei die Ergebnisse beider Methoden in einem Öko‐Portfolio verknüpft werden können. Die Entwicklung sowohl ökologisch als auch ökonomisch effizienter Prozesse kann somit bereits in der frühen Designphase der chemischen Prozessentwicklung gezielt unterstützt und gesteuert werden.

Green Chemistry for Postgraduates

The multidisciplinary nature of Green Chemistry is recognised worldwide as a route to the development of chemical products and processes with lower environmental impact. Green chemistry and sustainability have had a profound effect on the way industry wish to be perceived. To promote uptake of green and sustainable methodologies amongst the chemical and chemical-using industries requires the exemplification of green chemistry in education and training material to influence and inspire the next generation of scientists. Herein, we examine important aspect of successful graduate green chemistry courses and how the skills gained from such studies can open doors to careers in a wide cross section of chemistry related industries.

Computer-aided assessment of occupationally healthier processes during research and development stage

Each year more people die from occupational related diseases than are killed in industrial accidents. Therefore it is critical to start considering health aspect early when developing a new chemical process. In this paper, a computer-aided tool for assessing inherent occupational health is proposed for chemical process research and development stage. The method was developed based on the reaction chemistry data, which is the only data available at this stage. Three types of approaches were formulated to calculate the route index value using additive type, average type and worst case type calculations. The tool can be used to rank the alternative chemical synthesis routes by their health properties as well as characterize the hazard level of single process. Finally the tool was applied to six process routes for methyl methacrylate production for demonstration. The case study revealed hazards of the processes from different perspectives, e.g. the results from the additive-type calculation were mainly affected by the total number of steps in the route, which indicates the impact of process complexity on the level of hazard. The introduction of such tool provides a swift yet reliable means that will encourage health criteria to be considered earlier in process development besides economic, safety and environment.

Nanostructured Catalysts for Organic Transformations

The development of green, sustainable and economical chemical processes is one of the major challenges in chemistry. Besides the traditional need for efficient and selective catalytic reactions that will transform raw materials into valuable chemicals, pharmaceuticals and fuels, green chemistry also strives for waste reduction, atomic efficiency and high rates of catalyst recovery. Nanostructured materials are attractive candidates as heterogeneous catalysts for various organic transformations, especially because they meet the goals of green chemistry. Researchers have made significant advances in the synthesis of well-defined nanostructured materials in recent years. Among these are novel approaches that have permitted the rational design and synthesis of highly active and selective nanostructured catalysts by controlling the structure and composition of the active nanoparticles (NPs) and by manipulating the interaction between the catalytically active NP species and their support. The ease of isolation and separation of the heterogeneous catalysts from the desired organic product and the recovery and reuse of these NPs further enhance their attractiveness as green and sustainable catalysts. This Account reviews recent advances in the use of nanostructured materials for catalytic organic transformations. We present a broad overview of nanostructured catalysts used in different types of organic transformations including chemoselective oxidations and reductions, asymmetric hydrogenations, coupling reactions, C-H activations, oxidative aminations, domino and tandem reactions, and more. We focus on recent research efforts towards the development of the following nanostructured materials: (i) nanostructured catalysts with controlled morphologies, (ii) magnetic nanocomposites, (iii) semiconductor-metal nanocomposites, and (iv) hybrid nanostructured catalysts. Selected examples showcase principles of nanoparticle design such as the enhancement of reactivity, selectivity and/or recyclability of the nanostructured catalysts via control of the structure, composition of the catalytically active NPs, and/or nature of the support. These principles will aid researchers in the rational design and engineering of new types of multifunctional nanocatalysts for the achievement of green and sustainable chemical processes. Although the past decade has brought many advances, there are still challenges in the area of nanocatalysis that need to be addressed. These include loss of catalytic activity during operation due to sintering, leaching of soluble species from the nanocatalysts under harsh reaction conditions, loss of control over well-defined morphologies during the scale-up synthesis of the nanocomposites, and limited examples of enantioselective nanocatalytic systems. The future of nanocatalyst research lies in the judicious design and development of nanocomposite catalysts that are stable and resistant to sintering and leaching, and yet are highly active and enantioselective for the desired catalytic organic transformations, even after multiple runs. The successful generation of such multifunctional nanocatalysts especially in tandem, domino, or cascade reactions would provide a powerful tool for the establishment of green and sustainable technologies.

Clear castable polyurethane elastomer for fabrication of microfluidic devices.

Polydimethylsiloxane (PDMS) has numerous desirable properties for fabricating microfluidic devices, including optical transparency, flexibility, biocompatibility, and fabrication by casting; however, partitioning of small hydrophobic molecules into the bulk of PDMS hinders industrial acceptance of PDMS microfluidic devices for chemical processing and drug development applications. Here we describe an attractive alternative material that is similar to PDMS in terms of optical transparency, flexibility and castability, but that is also resistant to absorption of small hydrophobic molecules.

Expanding GREENSCOPE beyond the gate: a green chemistry and life cycle perspective

Industrial processes, particularly those within the chemical industry, contribute products and services to improve and increase society’s quality of life. However, the transformation of raw materials into their respective final goods involves the consumption of mass and energy and the possible generation of by-products and releases. To address these issues, the new approach for chemical processing is focused on sustainable production: minimize raw material consumption and energy loads, minimize/eliminate releases, and increase the economic feasibility of the process. To evaluate these advances, a sustainability assessment methodology, GREENSCOPE, has been developed into a tool to evaluate and assist in the synthesis and design of chemical processes. New process sustainability indicators have been proposed based on input/output process data, and the base-case ratio approach is implemented to predict process changes from known process performance data and design relationships. In addition, a discussion regarding the implications of using sustainability evaluations beyond the process boundaries, applying the principles of green chemistry in all steps of chemical process development, and a description of their benefits to the life cycle inventory and the subsequent life cycle assessment is included. Finally, a new methodology approach to integrate GREENSCOPE into a life cycle inventory to develop sustainable systems is introduced.

Molecularly Imprinted Ru Complex Catalysts Integrated on Oxide Surfaces

Selective catalysis is critical for the development of green chemical processes, and natural enzymes that possess specialized three-dimensional reaction pockets with catalytically active sites represent the most sophisticated systems for selective catalysis. A reaction space in an enzyme consists of an active metal center, functional groups for molecular recognition (such as amino acids), and a surrounding protein matrix to prepare the reaction pocket. The artificial design of such an integrated catalytic unit in a non-enzymatic system remains challenging. Molecular imprinting of a supported metal complex provides a promising approach for shape-selective catalysis. In this process, an imprinted cavity with a shape matched to a template molecule is created in a polymer matrix with a catalytically active metal site. In this Account, we review our studies on molecularly imprinted metal complex catalysts, focusing on Ru complexes, on oxide surfaces for shape-selective catalysis. Oxide surface-attached transition metal complex catalysts not only improve thermal stability and catalyst dispersion but also provide unique catalytic performance not observed in homogeneous precursors. We designed molecularly imprinted Ru complexes by using surface-attached Ru complexes with template ligands and inorganic/organic surface matrix overlayers to control the chemical environment around the active metal complex catalysts on oxide surfaces. We prepared the designed, molecularly imprinted Ru complexes on SiO(2) surfaces in a step-by-step manner and characterized them with solid-state (SS) NMR, diffuse-reflectance (DR) UV-vis, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller isotherm (BET), X-ray fluorescence (XRF), and Ru K-edge extended X-ray absorption fine structure (EXAFS). The catalytic performances of these Ru complexes suggest that this process of molecular imprinting facilitates the artificial integration of catalytic functions at surfaces. Further advances such as the imprinting of a transition state structure or the addition of multiple binding sites could lead to systems that can achieve 100% selective catalysis.

Looking at the Cost: Using Flow Analysis to Assess and Improve Chemical Production Processes

AbstractIdentifying process alternatives to reduce the cost of product manufacturing is a key objective in process development and optimization. This article starts out by presenting the fundamental principles of flow‐based analysis methods. Material and energy flow analysis, with cost flow added, is then applied to chemical process development. An example shows that the method of charging cost to the flows that exit the production steps influences the recognizability of the cost reduction options. A more thorough analysis and understanding would be beneficial as a basis for identifying best‐practice recommendations. For industrial use, the suitability of existing cost flow analysis tools could be improved by enabling the use of a variety of allocation methods, data exchange with standard tools in process engineering, and improved user interfaces.

BIOCOMPATIBILITY AND MECHANICAL PROPERTIES OF A MWCNTS/CHITOSAN COMPOSITE

Virtual reality in chemical engineering features real-time simulation of complex industrial processes by utilizing multi-scale computation paradigm, and its realization is premised on global hydrodynamic modeling of the processes. Initial energy-minimization multi-scale (EMMS) model, though originally proposed for gas–solid fast fluidization, is extended to bubbling fluidization and in both axial and radial directions, so as to enable unified modeling of the entire gas–solid fluidization regime and theoretical computation of axial and radial heterogeneities in gas–solid flow. By applying the EMMS and its extension models to the segments divided from complex gas–solid reactors, an EMMS-based general method is proposed for global hydrodynamic calculation of the complex systems. Compared with traditional empirical schemes, the EMMS-based method avoids pre-separating the complex systems into various reaction zones until each has a single and simple flow state. And its feasibility is demonstrated by performing full-loop computation of an industrial-scale circulating fluidized bed, but its flexibility to the complexities of industrial processes in configuration and hydrodynamics still needs to be increased further in order to develop a software package for chemical process and virtual reality technology development.

Regioisomerism in the Synthesis of a Chiral Aminotetralin Drug Compound: Unraveling Mechanistic Details and Diastereomer-Specific In-Depth NMR Investigations

During chemical process development of a novel 2-aminotetralin derivative intended for use as an antidepressant, scrutiny of the byproduct present in the drug molecule revealed a set of regioisomers. Detailed studies showed that this impurity issue originated from an early synthetic step in which a brominated tetralone motif was generated in a ring-closing protocol. It was found that this reaction was accompanied by a migration of the aromatic bromo substituent via different bromonium species along two discrete pathways. This example of the halogen dance reaction resulted in the formation of a series of tetralone impurities with a bromine distributed across all available aromatic positions of the tetralin nucleus. Subsequently, when subjected to reductive amination conditions, each of these tetralones gave rise to pairs of aminotetralins in a diastereomeric relationship. NMR investigations revealed that the alicyclic portion of the compounds thus formed displayed very complex signal patterns, which required further in-depth studies using a variety of sophisticated techniques. As a result, a deep insight into the structural features of the current 2-aminotetralin family was obtained, which is emphasized by the definition of a novel "0.2 ppm rule" allowing the absolute configuration at tetralin C-2 to be determined.

Silica in Water: A Potentially Valuable Reaction Medium for the Synthesis of Pyrano[2,3-c]pyrazoles

In the last decade, multicomponent reactions have been much utilized for the synthesis of diverse highly functionalized molecules 1 via the formation of carbon-carbon and carbon-heteroatom bonds in one pot; as an outcome, they have appeared as a significant tool in organic synthesis. 2 These reactions are straightforward one step transformations involving a pair of reactions in which the product of the first is a substrate for the second. This technique becomes even more attractive and efficient if it works under greener reaction conditions. Green chemistry has created its own position in organic chemistry, since it has been demonstrated that how fundamental scientific methodologies can protect human health and the environment in an economically beneficial manner. 3 Therefore, there has been great quest towards the development of greener chemical processes. A part of this quest involves the search of surrogates for the traditionally employed homogenous catalysts. In this regard, many efforts have been made to prepare

ChemInform Abstract: Selective Liquid Phase Oxidation with Supported Metal Nanoparticles.

AbstractReview: 206 refs.

Hydrodynamic viability of chemical looping processes by means of cold flow model investigation

SINTEF Energy Research and the Norwegian University of Science and Technology – NTNU have proposed a 150kWth reactor system design aiming at further development of chemical looping processes. It consists of a double loop circulating fluidized bed, meant to be used as a platform to study atmospheric chemical looping combustion configurations, as well as other possible chemical looping processes e.g. gas turbine combustion and reforming. The hydrodynamic viability of the design needs to be tested by means of a cold flow model, operated without chemical reactions. An evaluation of the state of the art within cold flow model testing was done. It led to the choice of building a full scale (i.e. 1:1) cold model of the 150kWth hot rig design, in order to reduce wall-effects which have considerably larger influence at smaller reactor diameters than on larger ones.The cold flow model was extensively tested and experimental results are presented. The aimed design condition, mirroring a chemical looping combustion process adapted to steam generation, was achieved successfully and in a stable way. The performance of the reactor system was further tested in off-design conditions to define operational guidelines for the hot operation. In addition, attempts were done to resemble other chemical looping processes, getting some understanding of how the reactor system may perform and consequently providing solid hydrodynamic bases to improve the design for those applications. In all cases, stable operational sets were found in order to satisfy the cold flow model hydrodynamic requirements consistently with the actual high temperature processes.

Sustainability Indicators for Chemical Processes: II. Data Needs

To begin repair of the environmental quality of the planet, there is a need to embrace sustainable development at many levels of the chemical industry and society. One such manner in which the chemical industry is responding to this need is through sustainability evaluations, retrofits, and new process designs. For improving the sustainability of chemical processes, the first contribution of this set of articles presented a taxonomic classification, definition, and scale for measuring sustainability indicators according to the GREENSCOPE (Gauging Reaction Effectiveness for the ENvironmental Sustainability of Chemistries with a multi-Objective Process Evaluator) methodology. To generate a sustainability assessment and yield a more sustainable process in the end, a model must have available data; that is, data are not the final goal but are mandatory to arrive there. This second contribution extends this methodology by identifying data requirements when calculating the indicators. Each indicator is mathematically defined, emphasizing realistic usage, and connecting the mathematical formulas for the indicators with their data requirements. In addition, data-source alternatives to fulfill the input requirements and potential data gaps for the calculation of the sustainability indicators for a new process technology or an existing manufacturing plant are proposed and discussed. This work further provides the practical connection between theoretical definitions of sustainability, data needs, and mathematical definitions of indicators for process sustainability assessment. With the accomplishment of this second contribution, sustainability assessment can be achieved and proposed as a reliable and robust tool for the development and optimization of chemical processes.

Determination of catalytic reaction mechanisms by isotopic frequency response

Efficient catalysts are of extraordinary importance for the development of efficient chemical processes as well as applications such as energy storage. Rational development of catalysts requires a mechanistic understanding of the catalytic reaction. Since steady-state investigations are insufficient to gain mechanistic understanding, transient methods such as SSITKA and frequency response have been developed. In this paper we provide a theoretical basis for a frequency response method based on variations in the isotopic composition of the reactant. This approach is particularly useful, since it permits transient investigations under quasi-steady state conditions and because the response is linear.

Sustainability assessment of novel chemical processes at early stage: application to biobased processes

Chemical conversions have been a cornerstone of industrial revolution and societal progress. Continuing this progress in a resource constrained world poses a critical challenge which demands the development of innovative chemical processes to meet our energy and material needs in a sustainable way. This challenge forms the basis for this article. We report a method for quick preliminary assessment of chemical processes at the laboratory stage. The proposed method enables a review of chemical processes within a broader sustainability context. It is inspired by green chemistry principles, techno-economic analysis and some elements of environmental life-cycle assessment (LCA). This method evaluates a proposed chemical process against comparable existing processes using a multi-criteria approach that integrates various economic and environmental indicators. An effort has been made to incorporate quantitative and qualitative information about the processes while making the method transparent and easy to implement based on information available at an early stage in process development. The idea is to provide a data-based assessment tool for chemists and engineers to develop sustainable chemistry. This paper describes the method in detail and examines plausibility of the results. A biobased process for the production of but-1,3-diene has been analyzed using this method. This biobased process is compared with a conventional process for the production of but-1,3-diene from petroleum sources. The effects of uncertainty in the underlying model parameters and assumptions are also analyzed, along with the effect of system boundary selection on the assessment outcome. Analysis and testing of the method shows that it can be used as a valuable tool for sustainable process development.

Chemical looping processes for CO2 capture and carbonaceous fuel conversion – prospect and opportunity

Chemical looping processes offer a compelling way for effective and viable carbonaceous fuel conversion into clean energy carriers. The uniqueness of chemical looping processes includes their capability of low cost in situ carbon capture, high efficiency energy conversion scheme, and advanced compatibility with state-of-the-art technologies. Based on the different functions of looping particles, two types of chemical looping technologies and associated processes have been developed. Type I chemical looping systems utilize oxygen carrier particles to perform the reduction–oxidation cycles, while Type II chemical looping systems utilize CO2 carrier particles to conduct carbonation–calcination cycles. The exergy analysis indicates that the chemical looping strategy has the potential to improve fossil fuel conversion schemes. Chemical looping particle performance and looping reactor engineering are the key drivers to the success of chemical looping process development. In this work, the desired particle characterization and recent progress in mechanism studies are generalized, which is followed by a discussion on the looping reactor design. This perspective also illustrates various chemical looping processes for combustion and gasification applications. It shows that both Type I and Type II looping processes have great potentials for flexible and efficient production of electricity, hydrogen and liquid fuels.

Selective liquid phase oxidation with supported metal nanoparticles

Over the past twenty years there has been intense interest in the design and understanding of catalysis by gold. More recently, it has been observed that alloying gold with a second metal greatly enhances the catalytic efficacy. These supported nanoparticles offer great potential as catalysts for the synthesis of fine chemicals and they are now at the stage where they can contribute to the sustainable development of chemical processes, in particular selective oxidation. A number of factors have contributed to this increased interest; namely, environmental issues promoting the need for more atom efficient processes and the new advances in the synthesis of nanoparticles as well as the characterisation methods available for their study. New catalytic materials obtained by careful control of the morphology of the metal nanoparticles and their use under solvent-free conditions all contribute to the latest developments. Most importantly their use can obviate the need to use stoichiometric oxidants. In this perspective we demonstrate the recent advances in these materials for selective oxidation reactions.

Data Driven Modelling and Control of Batch Processes in the Pharmaceutical Industry

Regulatory changes in the pharmaceutical industry have recast the role of chemical engineering in the development of processes for the large-scale manufacture of Active Pharmaceutical Ingredients. Health authorities' expectations have increased regarding proven demonstration of adequate process performance, process robustness, and quality control across development and manufacturing scales. These expectations have substantially increased the demands of experimental data collection, process monitoring, and multivariate process understanding. To address these requirements, innovative implementation of established and emerging automation, modeling, data management, and process monitoring techniques have been increasingly added to the repertoire of process development tools in particular, those carried out in agitated stirred tanks. This article will introduce the application of these techniques across the range of process development (from early to late phase) challenges. In particular, this article describes the implementation of Data Exploration Analysis to results obtained with automated parallel experimentation for batch reaction characterization and automated batch crystallization processes integrated to population balance modeling. Collectively these examples of new strategies for the automation of experimental batch processes, data analysis, and modeling provide an overview of recent trends in pharmaceutical chemical process development.

Monitoring On‐Chip Pictet–Spengler Reactions by Integrated Analytical Separation and Label‐Free Time‐Resolved Fluorescence

High-throughput screening for optimal reaction conditions and the search for efficient catalysts is of eminent importance in the development of chemical processes and for expanding the spectrum of synthetic methodologies in chemistry. In this context we report a novel approach for a microfluidic chemical laboratory integrating organic synthesis, separation and time-resolved fluorescence detection on a single microchip. The feasibility of our integrated laboratory is demonstrated by monitoring the formation of tetrahydroisoquinoline derivatives by Pictet-Spengler condensation. After on-chip reaction the products and residual starting material were separated enantioselectively on the same chip. On-chip deep UV laser-induced fluorescence detection with time-correlated single photon counting was applied for compound assignment. The system was utilized to screen reaction conditions and various substrates for Pictet-Spengler reactions on-chip. Finally, the microlab was successfully applied to investigate enantioselective reactions using BINOL-based phosphoric acids as organocatalysts.