This is the first ever use of these salts to convert sugars into a variety of chemical compounds for biofuel production
Scientists from the Singapore Institute of Bioengineering and Nanotechnology have uncovered new properties of imidazolium salts that suggest they could play a vital role in disease prevention and treatment. The article on the redox properties of these salts was published in the scientific journal Journal of the American Chemical Society.
In a separate study published in the journal Angewandte Chemie International Edition, the researchers published the first-ever use of these salts to convert sugars into a variety of chemical compounds for biofuel production.
The researchers successfully used these salts to develop a catalytic system for converting sugars into a substance called 5-hydroxymethylfurfural (HMF), a key compound used in bio-fuel chemistry and the oil industry.
In a study published in the first journal, the researchers describe how they used these salts to successfully synthesize uniform gold nanoparticles in seconds at room temperature. The thinnest nanoparticles (1-2 nanometers) remained stable for up to six months at four degrees Celsius.
Unlike common synthesis methods that use redox processes using boranes or borohydrides, the salts method does not require strong redox agents and at the same time they create gold nanoparticles under gentle conditions and very efficiently. The sensitive synthesis method of the salts can be easily used in industrial applications.
Imidazolium salts are ionic liquids at room temperature, chemically stable and with low vapor pressure, which are used as solvents in various organic reactions. While the physical properties of these salts have been extensively studied, their biochemical properties and medical applications have hardly been mentioned at all in the scientific literature.
The lead researcher, Dr. Yugen Zhang, said, "Our successful use of these salts as restorative agents led us to believe that we could also use these compounds as antioxidants that trap oxygen and thereby reduce the damage to the body that results from reactive oxygen species."
Environmental stressors triggered by an unhealthy lifestyle, such as excessive alcohol consumption, exposure to toxins and drugs, smoking and lack of sleep, can cause the body to produce superoxygen radicals known as reactive oxygen species (ROS) that are capable of causing to cellular damage through oxidation.
Oxidative stress as a result of these conditions is involved in most diseases, including cancer, heart disease, liver disease, degenerative diseases, immune system disorders and aging. Radical-trapping antioxidants help capture free radicals in the body's cellular system, thus reducing the effect of these forms.
Imidazolium salts are precursors to substances called "N-heterocyclic carbenes" (N-Heterocyclic Carbenes, NHC). A natural form of NHC is a B vitamin (or thiamine) that serves an important biological role. Deficiency of this vitamin has been linked to oxidative stress. While natural antioxidants such as epigallocatechin gallate (EGCG), which is an extract of green tea, are known for preventing or slowing down oxidation processes in the body, they have relatively low activity and break down in the body quite quickly.
The lead researcher clarifies: "Our studies with cells showed that these salts have stronger antioxidant properties than EGCG and at the same time have less toxicity. They significantly reduce the levels of harmful compounds in liver cells eleven percent more than EGCG. In addition, the preparation of these salts is simple and cheap. Therefore, they hold great promise as a new type of antioxidants capable of being used in biomedical applications."
In another study by the same team, the researchers successfully used these salts to develop a catalytic system for converting sugars into a substance called 5-hydroxymethylfurfural (HMF), a key compound used in biofuel chemistry and the oil industry.
The depletion of fossil fuel reserves and the effects of global warming have made the search for alternative, renewable and durable energy sources a global and fatal concern. Today, biofuels are the only available durable source of liquid fuel, but a lack of efficient methods for converting sugars into chemical compounds used in biofuel production is hindering the replacement of fuel reserves by biomass (the total amount of living organisms in a given area).
The substance HMF and its derivatives converted in positions 2 and 5 of the furan can replace primary petroleum-based chemical building blocks, and several catalysts are known that are active in the conversion of sugars to obtain this substance.
However, most of them also lead to side reactions that produce unwanted byproducts, turning the HMF into an acid. Therefore, the use of these catalysts was often limited to simple sugar raw materials, such as fructose. They were unable to efficiently convert glucose, a more common and stable source of sugar.
Using the imidazolium salts as a starting point, the researchers developed NHC-based metal conjugates as catalysts for converting sugars into HMF. These offer a high degree of flexibility as the catalytic activity is controlled through specific modification of the properties of the NHC material. The researchers were able to obtain the substance HMF easily as the only product. The new catalytic system achieved the highest reported efficiency of obtaining HMF, to date, for both fructose as the starting material and glucose. The researcher clarifies, "Our survivals in obtaining the substance HMF were ninety-six percent for fructose and eighty-one percent for glucose. Since both the catalyst and the ionic liquid are recyclable, our technology is more environmentally friendly and could potentially lead to cost savings in biofuel production processes."
Adds one of the researchers, "We are excited by the enormous potential inherent in these innovative compounds regarding their impact on the fields of medicine and energy substitutes. Our discovery opens avenues for more effective treatments for various degenerative diseases, as well as for the preparation of biofuels, and thus we help alleviate some of the pressing concerns facing the global community."
