- Ph.D., Washington University
- CHM 302 – Inorganic Chemistry I
- CHM 406 – Physical Chemistry I
- CHM 408 – Physical Chemistry I Laboratory
- CHM 205 – General Chemistry I Laboratory
- CHM 400 – Seminar I
- CHM303 – Analytical Chemistry I
- CHM406 – Physical Chemistry II
- CHM409 – Physical Chemistry II Laboratory
- CHM206 – General Chemistry II Laboratory
- CHM401 – Seminar II
Polyethylene Glycol and Related Surfactants as Green Solvents for Chemical Synthesis
Traditional solvents in chemical synthesis are typically volatile, flammable and oftentimes toxic and harmful to the environment. One of the 12 Principles of Green Chemistry consequently concerns the replacement of traditional solvents with environmentally benign ones. One potential solvent that has been evaluated as “green solvent” is polyethylene glycol (PEG). Much less evaluated as green solvents are PEG related nonionic surfactants as defined in Scheme 1. As solvents, these may dissolve a wide variety of substances because of their amphiphilic structure. Just like PEG, they too are environmentally benign substances because they possess low vapor pressure, are biodegradable and with respect to toxicity, there are no concerns because they are already widely used in industrial and household products. As a proof of concept, we have been able to carry out a particular Diels-Alder reaction in these surfactant media.
SCheme 1 (Image above)
- PEG where, as an example, for PEG 200 the average molecular weight is 200 g·mol-1
- Triton X-100. The subscript m indicates the number of carbon atoms in the alkyl chain (C), while n and q are the repetition units of ethylene oxide (E) and propylene glycol (P), respectively.
The present research focus is placed on characterizing these nonionic surfactants as solvents in comparison to PEG. Very excitingly, since 2015 there is an ongoing research collaboration with the Buntkowsky group at the Technical University in Darmstadt, Germany. Their expertise is in solid-state NMR spectroscopy and thus they study systems that are solid such as catalyst materials, which often very porous materials with large surface areas. Interestingly, PEG is a glass former and thus, when frozen preserves the structure of the liquid state. Moreover, we found out, that although the PEG related surfactants form at least in part crystalline structures, there are surprisingly still molecular motions active in the frozen state. Thus, we are using solid state research to learn more about the liquid structure and dynamics of PEG and related surfactants.
Aside from gaining a better fundamental understanding of PEG and related surfactants as solvents, it is hoped that these research efforts will stimulate synthetic chemists to also consider nonionic surfactants as a vital reaction medium.