- Email: [email protected]
2013 Danckwerts special issue on molecular modelling in chemical engineering
Chemical Engineering Science 121 (2015) 1–2
Contents lists available at ScienceDirect
Chemical Engineering Science journal homepage: www.elsevier.com/locate/ces
Editorial
2013 Danckwerts special issue on molecular modelling in chemical engineering
The 2013 Nobel Prize in Chemistry highlighted the importance of molecular modelling in improving our understanding of the natural world over the past 50 years. As methods and commodity computer power have grown over the past two decades or so, molecular modelling has become mainstream in chemical engineering, where it is increasingly being viewed as an essential element of the engineer's tool box, both in academe and in industry. Molecular modelling stand-alone has long had a place in knowledge discovery in the field, but its greatest value in research comes through its combination with experiment. In the enterprise context, molecular modelling is now used to initially screen potential drug candidates, materials, complex fluids and other systems, as well as provide data that may be impossible to obtain otherwise in our modern, cost-constrained world. This special issue, which was commissioned in the wake of Prof. Sharon Glotzer's 2013 Danckwerts Lecture in which molecular modelling featured, is intended to demonstrate some of its potential in the field. The special issue is composed of 30 papers from across the world that may be broken up into eight sets. The first of these sets, which is composed of five reports, is concerned with self-assembly, a hugely important area for the future of the discipline. This field gains particularly from the capacity of molecular modelling to elucidate the relationship between molecular and nanoscale building blocks on the one hand and the structures that are created through their self-assembly on the other (Singh and coworkers, India; Mavrantzas and co-workers, Greece), as well as the driving forces for this self-assembly (Yu and co-workers, Australia; Glotzer, USA; Fichthorn, USA). The next set of three papers is focused on crystallisation, a problem of importance across areas as diverse as pharmaceuticals and explosives. In the first of these, Salvalaglio and co-workers (Switzerland) use an advanced molecular dynamics technique to elucidate the initial stages of crystallisation, a process that is very difficult to probe experimentally. The contribution of Adjiman and co-workers (UK), the second in this set, highlights the potential of molecular modelling to identify drug molecule polymorphs, which is critical for the pharmaceutical industry as it seeks to provide a safe, reliable supply of advanced drugs profitably. The final report in this set, from the group of Vlugt (The Netherlands), is focused on the crystallisation of hydrated nickel and magnesium sulphates, which represent another significant industrially important problem. The third set of papers in this Special Issue is primarily concerned with the prediction of fluid properties and phase equilibria. The first three contributions in this set, from the groups http://dx.doi.org/10.1016/j.ces.2014.10.033 0009-2509/& 2014 Published by Elsevier Ltd.
of Vrabec (Germany), Rey (Canada) and Haase (Germany), are excellent examples of how molecular simulation can yield data useful in design that would otherwise remain unavailable due to, for example, the extreme conditions (e.g. very high pressures), vast array of possibilities, and cost. The penultimate paper in this set, that of Laso and co-workers (Spain), shows how advanced Monte Carlo techniques can be used to probe the conformation, bulk and interfacial structure, and entanglements of dense systems of chains composed of tangent hard spheres, which serve as models for a variety of soft materials. The set is completed by the review of English and MacElroy (Ireland), which demonstrates how molecular modelling has helped elucidate the fundamental and applied aspects of clathrate hydrates over the past 30 years, and what needs to be done to continue this contribution moving forward. The fourth set of contributions are all focused on ionic liquids, which are of growing importance as ‘green’ solvents and reaction media. The main theme of the first two contributions of this set (Lee and Lin, Taiwan; Suojiang Zhang and co-workers, China) is the use of molecular modelling to screen many potential ionic liquids for specific applications, a task that would be very difficult to achieve in the laboratory alone, if at all. The final contribution in this set (Gupta and Jiang, Singapore) reviews past molecular modelling of the use of ionic liquids in dissolution of cellulose to show that hydrogen bonding plays a critical role in this process. The fifth set of papers in this Special Issue present the work of three groups that have focused on developing multiscale approaches to modelling systems that involve chemical reactions. The first two contributions (Sutton and Vlachos, USA; group of Wei Ge and Jinghai Li, China) focus on two very different methodological approaches for making the modelling of reactive systems from the atomic to the process scale possible. The third paper in this set (Mushrif and coworkers, Singapore) reviews the application of molecular and multiscale modelling to biomass conversion. The next set of three papers focus on transport phenomena in polymers – the first two (Searles and coworkers, Prakash and coworkers, both of Australia) are concerned with methodological issues around predicting the rheology of polymer liquids, whilst the last of this set (Noorjahan and Choi, Canada) is concerned with predicting the diffusion of penetrant molecules within polymers, which is of wide practical interest; separation membranes, protective films for food, and contact lenses are just three examples. The penultimate set of contributions here are focused on fluids in nanoporous media, an area that has long benefited from molecular modelling as in many cases the practical system sizes – which may be just a nanometre – have long been accessible to the method. However, these six contributions, three from the UK
2
Editorial / Chemical Engineering Science 121 (2015) 1–2
(Striolo and co-workers, Newsome and Coppens, Sarkisov and Kim), two from Australia (Bhatia and co-workers, and Do and coworkers) and one from India (Ayappa and co-workers), represent the application of molecular modelling to elucidate the effect that realities of nanoporous materials have on their performance, a relatively recent development in molecular modelling of such systems. The final set of two papers are focused on biomolecules (Jian Zhou and co-workers, China; Middelberg and co-workers, Australia). Whilst molecular modelling of nature's biomolecules in their native state has a long history, modelling beyond this scenario as undertaken in the two reports here has been slower – the barriers are, however, starting to be addressed and we should see much more of this in the chemical engineering field moving forward. One of us (DT) had the honour of serving as Guest Editor for a Symposium in Print on Molecular Modelling published by Chemical Engineering Science in 1994 (volume 49, issue 17). It is interesting to contemplate, looking at the papers of the two Special Issues, in what ways the field has changed over the 20 years that have elapsed. Generally, contributions in the 1994 issue were more fundamentally oriented; contributions in the present issue seem more focussed on systems that are of immediate relevance to the chemical processing, materials, and pharmaceutical industries, to clean energy production, health, and the protection of the environment. In 1994 there was considerable emphasis on statistical mechanical theory and equations of state for chain fluids; in 2014 there is less theory and more computer simulations, many of them conducted using software packages, and the arsenal of computational tools has expanded to include electronic structure calculations. Self-organisation of amphiphilic systems, sorption and transport of fluids in microporous media were popular topics both then and now, the 2014 papers giving more consideration to the complexities and imperfections
of real-life structure. While in 1994 simulations often focused on details of specific systems investigated via simulations of either atomistic or coarse-grained models, multiscale modelling involving more than one interconnected levels of representation has become widespread in 2014. This is necessary for addressing long length and time scale phenomena and very much in line with the systems-oriented approach to process and product design typical of chemical engineers. Methodologies for dealing with infrequent event processes, such as nucleation, in a predictive manner have become more prominent. The great increase in accessible computational resources over the last twenty years, Graphics Processing Units being a notable example, has dramatically augmented the scope and impact of molecular simulations in chemical engineering research. Apart from demonstrating that molecular modelling has much to offer chemical engineering, this special issue is also meant to signal to all potential authors that Chemical Engineering Science is open to accepting high quality manuscripts that exploit the approach either alone, as part of a multiscale approach, or in combination with experiment. We look forward to receiving these contributions!
Managing Guest Editor Mark J. Biggs Loughborough University, UK The University of Adelaide, Australia
Guest Editor Doros Theodorou National Technical University of Athens, Greece
Contents lists available at ScienceDirect
Chemical Engineering Science journal homepage: www.elsevier.com/locate/ces
Editorial
2013 Danckwerts special issue on molecular modelling in chemical engineering
The 2013 Nobel Prize in Chemistry highlighted the importance of molecular modelling in improving our understanding of the natural world over the past 50 years. As methods and commodity computer power have grown over the past two decades or so, molecular modelling has become mainstream in chemical engineering, where it is increasingly being viewed as an essential element of the engineer's tool box, both in academe and in industry. Molecular modelling stand-alone has long had a place in knowledge discovery in the field, but its greatest value in research comes through its combination with experiment. In the enterprise context, molecular modelling is now used to initially screen potential drug candidates, materials, complex fluids and other systems, as well as provide data that may be impossible to obtain otherwise in our modern, cost-constrained world. This special issue, which was commissioned in the wake of Prof. Sharon Glotzer's 2013 Danckwerts Lecture in which molecular modelling featured, is intended to demonstrate some of its potential in the field. The special issue is composed of 30 papers from across the world that may be broken up into eight sets. The first of these sets, which is composed of five reports, is concerned with self-assembly, a hugely important area for the future of the discipline. This field gains particularly from the capacity of molecular modelling to elucidate the relationship between molecular and nanoscale building blocks on the one hand and the structures that are created through their self-assembly on the other (Singh and coworkers, India; Mavrantzas and co-workers, Greece), as well as the driving forces for this self-assembly (Yu and co-workers, Australia; Glotzer, USA; Fichthorn, USA). The next set of three papers is focused on crystallisation, a problem of importance across areas as diverse as pharmaceuticals and explosives. In the first of these, Salvalaglio and co-workers (Switzerland) use an advanced molecular dynamics technique to elucidate the initial stages of crystallisation, a process that is very difficult to probe experimentally. The contribution of Adjiman and co-workers (UK), the second in this set, highlights the potential of molecular modelling to identify drug molecule polymorphs, which is critical for the pharmaceutical industry as it seeks to provide a safe, reliable supply of advanced drugs profitably. The final report in this set, from the group of Vlugt (The Netherlands), is focused on the crystallisation of hydrated nickel and magnesium sulphates, which represent another significant industrially important problem. The third set of papers in this Special Issue is primarily concerned with the prediction of fluid properties and phase equilibria. The first three contributions in this set, from the groups http://dx.doi.org/10.1016/j.ces.2014.10.033 0009-2509/& 2014 Published by Elsevier Ltd.
of Vrabec (Germany), Rey (Canada) and Haase (Germany), are excellent examples of how molecular simulation can yield data useful in design that would otherwise remain unavailable due to, for example, the extreme conditions (e.g. very high pressures), vast array of possibilities, and cost. The penultimate paper in this set, that of Laso and co-workers (Spain), shows how advanced Monte Carlo techniques can be used to probe the conformation, bulk and interfacial structure, and entanglements of dense systems of chains composed of tangent hard spheres, which serve as models for a variety of soft materials. The set is completed by the review of English and MacElroy (Ireland), which demonstrates how molecular modelling has helped elucidate the fundamental and applied aspects of clathrate hydrates over the past 30 years, and what needs to be done to continue this contribution moving forward. The fourth set of contributions are all focused on ionic liquids, which are of growing importance as ‘green’ solvents and reaction media. The main theme of the first two contributions of this set (Lee and Lin, Taiwan; Suojiang Zhang and co-workers, China) is the use of molecular modelling to screen many potential ionic liquids for specific applications, a task that would be very difficult to achieve in the laboratory alone, if at all. The final contribution in this set (Gupta and Jiang, Singapore) reviews past molecular modelling of the use of ionic liquids in dissolution of cellulose to show that hydrogen bonding plays a critical role in this process. The fifth set of papers in this Special Issue present the work of three groups that have focused on developing multiscale approaches to modelling systems that involve chemical reactions. The first two contributions (Sutton and Vlachos, USA; group of Wei Ge and Jinghai Li, China) focus on two very different methodological approaches for making the modelling of reactive systems from the atomic to the process scale possible. The third paper in this set (Mushrif and coworkers, Singapore) reviews the application of molecular and multiscale modelling to biomass conversion. The next set of three papers focus on transport phenomena in polymers – the first two (Searles and coworkers, Prakash and coworkers, both of Australia) are concerned with methodological issues around predicting the rheology of polymer liquids, whilst the last of this set (Noorjahan and Choi, Canada) is concerned with predicting the diffusion of penetrant molecules within polymers, which is of wide practical interest; separation membranes, protective films for food, and contact lenses are just three examples. The penultimate set of contributions here are focused on fluids in nanoporous media, an area that has long benefited from molecular modelling as in many cases the practical system sizes – which may be just a nanometre – have long been accessible to the method. However, these six contributions, three from the UK
2
Editorial / Chemical Engineering Science 121 (2015) 1–2
(Striolo and co-workers, Newsome and Coppens, Sarkisov and Kim), two from Australia (Bhatia and co-workers, and Do and coworkers) and one from India (Ayappa and co-workers), represent the application of molecular modelling to elucidate the effect that realities of nanoporous materials have on their performance, a relatively recent development in molecular modelling of such systems. The final set of two papers are focused on biomolecules (Jian Zhou and co-workers, China; Middelberg and co-workers, Australia). Whilst molecular modelling of nature's biomolecules in their native state has a long history, modelling beyond this scenario as undertaken in the two reports here has been slower – the barriers are, however, starting to be addressed and we should see much more of this in the chemical engineering field moving forward. One of us (DT) had the honour of serving as Guest Editor for a Symposium in Print on Molecular Modelling published by Chemical Engineering Science in 1994 (volume 49, issue 17). It is interesting to contemplate, looking at the papers of the two Special Issues, in what ways the field has changed over the 20 years that have elapsed. Generally, contributions in the 1994 issue were more fundamentally oriented; contributions in the present issue seem more focussed on systems that are of immediate relevance to the chemical processing, materials, and pharmaceutical industries, to clean energy production, health, and the protection of the environment. In 1994 there was considerable emphasis on statistical mechanical theory and equations of state for chain fluids; in 2014 there is less theory and more computer simulations, many of them conducted using software packages, and the arsenal of computational tools has expanded to include electronic structure calculations. Self-organisation of amphiphilic systems, sorption and transport of fluids in microporous media were popular topics both then and now, the 2014 papers giving more consideration to the complexities and imperfections
of real-life structure. While in 1994 simulations often focused on details of specific systems investigated via simulations of either atomistic or coarse-grained models, multiscale modelling involving more than one interconnected levels of representation has become widespread in 2014. This is necessary for addressing long length and time scale phenomena and very much in line with the systems-oriented approach to process and product design typical of chemical engineers. Methodologies for dealing with infrequent event processes, such as nucleation, in a predictive manner have become more prominent. The great increase in accessible computational resources over the last twenty years, Graphics Processing Units being a notable example, has dramatically augmented the scope and impact of molecular simulations in chemical engineering research. Apart from demonstrating that molecular modelling has much to offer chemical engineering, this special issue is also meant to signal to all potential authors that Chemical Engineering Science is open to accepting high quality manuscripts that exploit the approach either alone, as part of a multiscale approach, or in combination with experiment. We look forward to receiving these contributions!
Managing Guest Editor Mark J. Biggs Loughborough University, UK The University of Adelaide, Australia
Guest Editor Doros Theodorou National Technical University of Athens, Greece