Researchers at the Institute of Bioengineering and Nanotechnology (IBN) have discovered a new chemical process that can convert adipic acid directly from sugar.
Adipic acid is an important chemical used to produce nylon for apparel and other everyday products like carpets, ropes and toothbrush bristles.
Commercially, adipic acid is produced from petroleum-based chemicals through the nitric acid oxidation process, which emits large amounts of nitrous oxides, a major greenhouse gas that causes global warming.
IBN Executive Director Professor Jackie Y Ying said: “In the face of growing environmental concerns over the use of fossil fuels and diminishing natural resources, there is an increasing need for a renewable source for energy and chemicals.
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We are excited that our new protocol can efficiently convert adipic acid from sugar, bringing us one step closer toward industrialisation. To complete this green technology, we are now working on using raw biomass as the feedstock
Dr Yugen Zhang, Institute of Bioengineering and Nanotechnology group leader in green chemistry and energy
“We have designed a sustainable and environmentally friendly solution to convert sugar into adipic acid via our patented catalytic process technology.”
Bio-based adipic acid can be synthesised from mucic acid, which is oxidised from sugar; and the mucic acid can be obtained from fruit peels.
Current processes are either performed using multiple steps with low product efficiency and yield, or under harsh reaction conditions using high-pressure hydrogen gas and strong acids, which are costly and unsafe.
IBN said the new chemical catalytic protocol it has designed is simple, efficient and green.
To convert mucic acid to adipic acid, the target reaction is deoxydehydration - oxygen and water will be removed simultaneously by reduction and dehydration.
The researchers found that by combining deoxydehydration and the transfer hydrogenation reaction - adding an alcohol solvent - in one reactor, they could obtain a high yield of adipic acid at 99 per cent of the starting material.
Existing protocols can only achieve a yield of around 60 per cent.
IBN said this method is ideal for industrial development because the process can be performed in one or two steps, the end product is pure, and the reaction conditions are mild and safe.
Dr Yugen Zhang, IBN group leader in green chemistry and energy, said: “This work shows the tremendous potential of developing bio-based adipic acid.
“We are excited that our new protocol can efficiently convert adipic acid from sugar, bringing us one step closer toward industrialisation. To complete this green technology, we are now working on using raw biomass as the feedstock.”
This finding was published recently in the leading chemistry journal Angewandte Chemie International Editionwork.
