Supercritical fluids are a gas that
is compressed and heated so that it shows properties
of a liquid and a gas at the same time. Supercritical
carbon dioxide can be used to dissolve materials
involved in chemical reactions. In this way,
it can replace organic solvents which are much
less environmentally friendly and generate
greater amounts of waste.
Thomas Swan have developed this
technology and built a "world's first"
site that uses supercritical carbon dioxide
to replace less environmentally-friendly organic
solvents in reactions including hydrogenation,
Friedel-Crafts alkylations and etherification.
The plant is the first full-scale facility
using supercritical fluids and can produce
up to 1,000 tonnes of specialist chemicals
Swans general manager, Dai
Hayward, says that the process may make chemical
reactions possible that were previously too
dirty or inneficient. Supercritical fluids
have demonstrated their potential to solve
some of the process problems encountered in
the chemical industry and, in partnership with
Nottingham University, we have transformed
the theory into a practical technology with
Carbon dioxide is the most common gas used as
a supercritical fluid but the use of propane,
propene and butane is also being studied.
A supercritical fluid shows the properties
of both a liquid and a gas.