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Technological Breakthrough in the Fight to Cut Greenhouse Gases
14 May, 2008 09:13 am
Two of the major problems facing scientists at the start of the 21st century are undoubtedly: combating climate change and breaking the reliance of the chemicals industry on starting materials derived from crude oil.
One factor that will help in reducing carbon dioxide emissions is the limited supply of crude oil – world wide production is expected to peak before 2020. Unfortunately, this raises another problem as about 10 per cent of crude oil is used not by the energy industry, but by the chemicals industry in the preparation of everything from plastic bags to pharmaceuticals. This represents an impending crisis for the chemicals industry as supplies of its raw material start to dry up and their cost escalates.
A recent breakthrough from a team of scientists at Newcastle University, in the UK, will help with both of these problems. The group, led by Professor of Organic Chemistry, Michael North, have found a way of converting waste carbon dioxide into a class of chemicals called ‘cyclic carbonates’. These cyclic carbonates are already commercially important chemicals used as solvents, monomers for polymer synthesis, intermediates for the synthesis of other chemicals and as the electrolyte in rechargeable batteries. They also have other potential applications including use as an anti-knocking agent in petrol if the cost of their manufacture can be reduced.
Cyclic carbonates are prepared by the reaction between an epoxide and carbon dioxide. However, current commercial processes require the use of reaction temperatures above 100 oC and / or high reaction pressures. Considerably more carbon dioxide is produced generating the energy to purify, heat and compress the carbon dioxide than is consumed by the reaction, so the commercial production of these chemicals is a net generator of carbon dioxide.
At Newcastle University, however, the team of scientists has successfully produced a catalyst which is capable of carrying out this reaction at atmospheric pressure and room temperature, and using a waste carbon dioxide stream at a concentration found in the outlet of a typical fossil fuel power station. The net result is to transform an important chemical reaction from one which produces carbon dioxide to one which reduces the carbon dioxide emissions of major fixed site carbon dioxide producers, helping to reduce greenhouse gas emissions. The catalyst (effectively a molecular machine which can repeat a chemical reaction many times without being destroyed itself) and the process have been patented by Newcastle University, and work is now underway to take the technology from the research laboratory to industrial utilization.
If fully implemented to satisfy the projected world-wide demand for cyclic carbonates, this technology would require 48 million tonnes of waste carbon dioxide each year, equating to 4 per cent of the UK’s current emissions (United Nations figures for 2004). Clearly by itself this will not solve the problem of global warming, but it is a part of the solution and should point scientists in the direction of other commercially important chemicals that can be prepared from waste carbon dioxide, thus solving two major challenges at once.