This paper presents a novel computer-aided molecular/mixture design (CAMD) methodology for the design of optimal solvents and solvent mixtures. The molecular/mixture design problem is formulated as a mixed integer nonlinear programming (MINLP) model in which a performance objective is to be optimized subject to structural, property, and process constraints. The general molecular/mixture design problem is divided into two parts. For optimal single-compound design, the first part is solved. For mixture design, the single-compound design is first carried out to identify candidates and then the second part is solved to determine the optimal mixture. The decomposition of the CAMD MINLP model into relatively easy to solve subproblems is essentially a partitioning of the constraints from the original set. This approach is illustrated through two case studies. The first case study involves the design of an optimal extractant for the separation of acetic acid from water by liquid-liquid extraction. The results suggest that the new extractant would be able to perform better than the extractant being widely used for this separation. The second case study is an industrial problem involving the optimal formulation for a pharmaceutical compound. The designed formulation is able to improve the water solubility of the compound by more many fold.

ABSTRACT. Ecosystem regime shifts, which are long-term system reorganizations, have profound implications for sustainability. There is a great need for indicators of regime shifts, particularly methods that are applicable to data from real systems. We have developed a form of Fisher information that measures dynamic order in complex systems. Here we propose the use of Fisher information as a means of: (1) detecting dynamic regime shifts in ecosystems, and (2) assessing the quality of the shift in terms of intensity and pervasiveness. Intensity is reflected by the degree of change in dynamic order, as determined by Fisher information, and pervasiveness is a reflection of how many observable variables are affected by the change. We present a new robust methodology to calculate Fisher information from time series field data. We demonstrate the use of Fisher information to detect regime shifts on a model for a shallow lake. Next, we use Fisher information to analyze marine ecosystem response to physical changes using real time-series data of a coastal marine ecosystem, the North Pacific Ocean.

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in Wiley Online Library (wileyonlinelibrary.com) Ionic liquids (IL), with their negligible vapor pressure, have the potential to replace volatile organic solvents in several processes. They also exhibit other unique characteristics, such as high thermal stability, wide liquid range, and wide electrochemical window, which make them attractive for many important applications. In addition, millions of ILs can be formed through different combination of cations, anions, and other functional groups. Till now, majority of work on IL selection, for a given application, is guided by trial and error experimentation. In this article, we present a computer-aided IL design framework, based on semiempirical structure-property models and optimization methods, which can consider several IL candidates and design optimal structures for a given application. This powerful methodology has great potential to act as a knowledge-based framework to aid synthetic chemists and engineers develop new ILs.

Recently, several energetic ionic salts and liquids have been proposed as novel high-energy materials, propellants, and explosives. The life cycle environmental impacts of these new energetic salts have not been previously studied. Environmental impacts arise both from release of these energetic materials themselves as well as from their synthesis. In this work, for the first time, we report the results of cradle-to-gate life cycle environmental impacts of production of energetic ionic salt 1,2,3-triazolium nitrate and compare it with traditional energetic material 2,4,6-trinitrotoluene (TNT). The results indicate that the production processes of ionic salt have a significantly higher environmental footprint than conventional energetic materials. The above result was consistent across all nine impact categories analyzed and can be directly attributed to energy intensive steps needed to prepare the ionic salt and its precursors. The findings suggest that ionic energetic materials have higher environmental impact than TNT from a life cycle perspective.