Water Used To Make Complicated Chain Of Chemical Reactions For Plastics And Medicines Much More Environmentally Friendly

Prof. Arkadi Vigalok from the School of Chemistry at Tel Aviv University has discovered a way to use water to make certain steps of a complicated chain of chemical reactions more environmentally-friendly.

Prof. Vigalok’s solution replaces chemical solvents, which can pollute the environment, with water.  Though chemists have long thought it possible, Prof. Vigalok’s approach has only rarely been even attempted.  His discovery was recently reported in the journal Angewandte Chemie, International Edition.

A Natural Solvent

“Ten to twenty chemical reactions may be done to make a single medicine, and in each step organic solvents are used,” Prof. Vigalok says. “If we can cut out their use by applying water instead, this could amount to a substantial advance.”  Prof. Vigalok noted that 100 kilograms (about 220 pounds) of solvents and materials might be used to produce 1 kilogram (about 2 pounds) of medicine.

In his new approach, water is mixed with organic compounds called aldehydes.  Prof. Vigalok discovered that an oxidation reaction needed to convert the materials to a new product, carboxylic acid, can be achieved without the use of solvents.  Moreover, the oxygen for this reaction is consumed directly from air.

Walking on Water

Because aldehydes don’t mix with water, they effectively “float” on the surface, where the reaction takes place.  This method can be applied to a few key stages in the reaction process.  The used water can then be easily recycled.

Prof. Vigalok and his team at Tel Aviv University join a small but growing group of chemists around the world who are making the chemical industry less destructive to the environment.  The field is now known as “Green Chemistry.”

“The plastics industry, the oil refinery business, every drug we take — they’re all parts of the chemical industry, the biggest industry in the world by far.  In making certain steps of the chemical process greener, we may not have an enormous impact on the environment at present, but we certainly challenge chemists to rethink methods used in traditional chemistry,” says Prof. Vigalok.