Time filter

Source Type

Wilmington, MA, United States

Atkinson M.B.J.,University of Massachusetts Boston | Oyola-Reynoso S.,Iowa State University | Luna R.E.,Harvard University | Bwambok D.K.,Warner Babcock Institute for Green Chemistry | Thuo M.M.,Iowa State University
RSC Advances | Year: 2015

Incompatible organic reactions impede efficient green synthesis by making multi-component or cascade reactions a big challenge. This review highlights pot-in-pot reactions (multiple reactions carried out in one pot by separating key reactions with a thin polymeric membrane) as an efficient, green synthetic alternative to conventional synthesis. We discuss the advantages of homogeneous processes to develop new cascade reaction sequences by reviewing the use of polymeric thimbles as selective semi-permeable walls. These thimbles allow small organic molecules to diffuse through while retaining polar reagents, polar solvents, and/or organometallic catalysts. The dynamic and versatile nature of this technique is demonstrated by performing 2- and 3-step cascade reactions in one glass pot. A pot-in-pot reaction approach to synthesis circumvents the need to isolate intermediates, or handling of toxic/unpleasant by-products, therefore enabling synthesis of otherwise challenging molecules, improving the efficiency, or enabling greener approaches to modular synthesis. © The Royal Society of Chemistry 2015.

Pont J.,Warner Babcock Institute for Green Chemistry
Chimica Oggi/Chemistry Today | Year: 2012

In some circles, there is a misguided tendency to believe that the application of Green Chemistry entails some sort of compromise in product performance and/or cost. Green Chemistryï¿12s principle goal is to reduce or eliminate the use and/or generation of hazardous materials or processes; in order to accomplish this goal, new materials and processes must ultimately be successfully deployed in commercial endeavour where, as a rule, performance and cost are paramount. Chemists and engineers are only successful in their design of safer materials and processes when their designs are consistent with market realities.

Cannon A.S.,00 Research Drive | Warner J.C.,Warner Babcock Institute for Green Chemistry | Koraym S.A.,Washington College | Marteel-Parrish A.E.,Washington College
Journal of Chemical Education | Year: 2014

An experiment focusing on the creation of phase diagrams involving nonconvalent derivatives of hydroquinone and bis[N,N-diethyl]terephthalamide (HQ-DETPA) is presented. A phase diagram was assembled by taking samples of different compositions (i.e., 40% hydroquinone and 60% bis[N,N-diethyl]terephthalamide, 70%/30%, etc.) and determining the melting points of each sample. This experiment is suitable for students enrolled in a physical chemistry class or materials science course and was effectively accomplished by three pairs of students. The experiment requires two 3-h lab sessions. Background information, experimental procedure and hazards, and results of the research are detailed. Results indicate that the noncovalent derivatization successfully provides a co-crystal that assembles into a 50:50 molar ratio. The eutectic points are shown to take place at the 25:75 and 75:25 molar ratios, respectively. Because entropy was the driving force behind the assembly of the co-crystals, the presence of a maximum point on the phase diagram, which represents the highest value of enthalpy and lowest point of entropy, was also witnessed and occurred at the 50:50 molar ratio of HQ to DETPA. © 2014 The American Chemical Society and Division of Chemical Education, Inc.

Schug T.T.,Esri | Abagyan R.,University of California at San Diego | Blumberg B.,University of California at Irvine | Collins T.J.,Carnegie Mellon University | And 18 more authors.
Green Chemistry | Year: 2013

A central goal of green chemistry is to avoid hazard in the design of new chemicals. This objective is best achieved when information about a chemical's potential hazardous effects is obtained as early in the design process as feasible. Endocrine disruption is a type of hazard that to date has been inadequately addressed by both industrial and regulatory science. To aid chemists in avoiding this hazard, we propose an endocrine disruption testing protocol for use by chemists in the design of new chemicals. The Tiered Protocol for Endocrine Disruption (TiPED) has been created under the oversight of a scientific advisory committee composed of leading representatives from both green chemistry and the environmental health sciences. TiPED is conceived as a tool for new chemical design, thus it starts with a chemist theoretically at "the drawing board." It consists of five testing tiers ranging from broad in silico evaluation up through specific cell- and whole organism-based assays. To be effective at detecting endocrine disruption, a testing protocol must be able to measure potential hormone-like or hormone-inhibiting effects of chemicals, as well as the many possible interactions and signaling sequellae such chemicals may have with cell-based receptors. Accordingly, we have designed this protocol to broadly interrogate the endocrine system. The proposed protocol will not detect all possible mechanisms of endocrine disruption, because scientific understanding of these phenomena is advancing rapidly. To ensure that the protocol remains current, we have established a plan for incorporating new assays into the protocol as the science advances. In this paper we present the principles that should guide the science of testing new chemicals for endocrine disruption, as well as principles by which to evaluate individual assays for applicability, and laboratories for reliability. In a 'proof-of-principle' test, we ran 6 endocrine disrupting chemicals (EDCs) that act via different endocrinological mechanisms through the protocol using published literature. Each was identified as endocrine active by one or more tiers. We believe that this voluntary testing protocol will be a dynamic tool to facilitate efficient and early identification of potentially problematic chemicals, while ultimately reducing the risks to public health. © 2013 The Royal Society of Chemistry.

Cinar S.,Iowa State University | Schulz M.D.,California Institute of Technology | Oyola-Reynoso S.,Iowa State University | Bwambok D.K.,Warner Babcock Institute for Green Chemistry | And 2 more authors.
Molecules | Year: 2016

Pot-in-pot reactions are designed such that two reaction media (solvents, catalysts and reagents) are isolated from each other by a polymeric membrane similar to matryoshka dolls (Russian nesting dolls). The first reaction is allowed to progress to completion before triggering the second reaction in which all necessary solvents, reactants, or catalysts are placed except for the starting reagent for the target reaction. With the appropriate trigger, in most cases unidirectional flux, the product of the first reaction is introduced to the second medium allowing a second transformation in the same glass reaction pot - albeit separated by a polymeric membrane. The basis of these reaction systems is the controlled selective flux of one reagent over the other components of the first reaction while maintaining steady-state catalyst concentration in the first "pot". The use of ionic liquids as tools to control chemical potential across the polymeric membranes making the first pot is discussed based on standard diffusion models - Fickian and Payne's models. Besides chemical potential, use of ionic liquids as delivery agent for a small amount of a solvent that slightly swells the polymeric membrane, hence increasing flux, is highlighted. This review highlights the critical role ionic liquids play in site-isolation of multiple catalyzed reactions in a standard pot-in-pot reaction. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Discover hidden collaborations