Reporter 414, 9 February 1998

A UK first for supercritical fluid extraction A breakthrough in supercritical fluid extraction capability has been announced by a ULIS 'spin-off' company.

Express Separations Ltd is the first UK company able to offer the complete range of extraction facilities, from initial laboratory scale trials through to plant scale production. The announcement will affect industries as diverse as pharmaceutical, cosmetics, food processing, food and non-food agriculture, metals processing and textiles. Background

Above their critical temperature, single substances do not condense or evaporate, but exist as fluids. These fluids possess unique properties intermediate in value between those of typical gases and liquids and can be controlled by temperature and pressure to obtain a wide range of extraction, reaction, separation and analytical chemistry applications. The term 'supercritical fluids' was coined to describe these media, and in recent years these have been widely exploited.

Current applications of supercritical fluid technology include

Clean and green Supercritical fluid technology (SFT) allows rapid extraction of targeted chemicals and essences using carbon dioxide and water as solvents. These are cheap, non-toxic, non-hazardous and recyclable and offer clear environmental advantages (carbon dioxide used is obtained as a by-product from fermentation and ammonia synthesis and does not add to the greenhouse effect). In contrast, many commercial extraction processes use organic solvents that not only leave trace contamination, but which are themselves a major environmental hazard. SFT takes less time than traditional extraction methods, leaves no toxic waste and does not affect the extracted or separated compound in any way, thereby giving an uncontaminated product.

As the shift continues away from finite resources, the capability of supercritical fluid technology demonstrates the increasing success of crop sources as raw materials for industrial use. By applying impregnation techniques to naturally occurring polymers, such as elastomers, Express Separations can produce a wide range of polymer replacements and natural fibre polymer mimics. These are cheap to produce, lightweight and durable, and are proving to be of great interest to automotive manufacturers as cost-effective replacements for plastics used in vehicle interiors.

For more information, contact Peter Hammond, Commercial Director,
Express Separations Ltd on +44 (0)113 233 6529, fax +44 (0)113 233
6490 or email


1. Express Separations Ltd grew out of the Supercritical Fluid Research Group in the School of Chemistry (the largest such group in Europe) and is headed by Professors Tony Clifford and Keith Bartle. It was created in 1993 and is managed by technology transfer company University of Leeds Innovations Ltd.

2. University of Leeds Innovations Ltd was created in 1971 to market intellectual property rights, licensing opportunities and commercial potential of innovations generated within University departments. It is one of the oldest and most successful companies of its type in the UK, creating more than twenty spin-off companies and several new business divisions. It is wholly owned by the University, to which it covenants all profits to help fund further research.

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