Green Chemistry Awards
2005 Crystal Faraday Green Chemical
Technology Awards
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The Crystal Faraday Awards celebrate outstanding achievement in the
commercialisation of Green and Sustainable Chemical Technology.
The award winner was announced at the IChemE Awards Dinner on 29
September 2005 at the Royal Courts of Justice, by Boris Johnson MP.
Davy Process Technology Limited received the award for their green
process for ethyl acetate production. This is a commercially successful
process: only 5 years after work began, Sasol has a commercial 50,000m
tpa plant in operation and a Chinese plant with double the capacity under
construction. Davy Process Technology Ltd is a UK company that provides
licences to operate advanced process technologies related to the
manufacture of oil and gas, petrochemicals, commodity chemicals, fine
chemicals and pharmaceuticals. Other short listed entrants included Cardiff
University in collaboration with Johnson Matthey Catalysts and Pfizer Global
R&D;
Davy Process Technology for Ethyl Acetate
production
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Ethyl Acetate
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Davy Process Technology has developed a process that enables ethyl acetate and a valuable
hydrogen by-product stream to be produced directly from ethanol. The process takes advantage
of the current industrial focus on renewable resources and the expansion in fermentation ethanol
production and breaks the feedstock link to volatile oil prices.
Dry ethanol is dehydrogenated to produce a crude ethyl acetate stream. This is selectively hydrogenated to
remove certain by-products that cannot be separated by distillation. The innovative refining section then
splits the azeotrope to produce a high purity ethyl acetate product. Unreacted ethanol is recycled to a
dehydration unit where it is combined with fresh ethanol and dried.
This process, which has been recognised by a number of awards including a Kirkpatrick Honour
Award, produces a high purity product. By-product hydrogen can provide producers with a key feedstock for
further downstream processes, the purity and pressure being adjusted to meet downstream requirements.
A 50,000 TPA plant is in operation in South Africa and a further plant using fermentation ethanol feedstock
is in the design phase.
UK AWARDS FOR GREEN CHEMICAL TECHNOLOGY
EDDS a Readily Biodegradable Chelant that can directly replace
EDTA and phosphonates
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EDDS A Biodegradable Alternative
EDDS (EthyleneDiamineDiSuccinate) (Figure 1) is a naturally occurring
chelant2 and is a structural isomer of EDTA that possesses two chiral centres
that are the key to its’ biodegradability. EDDS consists of two aspartic acid
units linked by an ethylene bridge and can exist as four stereoisomers. The
only stereoisomer that is readily biodegradable3 is the S,S form that is based
on the naturally occurring amino acid L-aspartic acid (Figure 2).
UK AWARDS FOR GREEN CHEMICAL TECHNOLOGY
EDDS a Readily Biodegradable Chelant that can directly
replace EDTA and phosphonates
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Chelating performance
EDTA and phosphonates are very effective chelants that form stable
complexes with a range of transition metals. EDDS and other biodegradable
chelants have to match this performance in the end application and the
particular combination of metals.
As illustrated (Figure 3), EDDS is more effective at chelating transition
metals like iron, copper and zinc than with alkali metals like calcium and
magnesium.
This means that EDDS is preferred where selective chelation of transition
metals is required in the presence of alkali metals. As metals are present in
varying amounts in different applications it means that research is required
on each system to find the optimum conditions.
UK AWARDS FOR GREEN CHEMICAL TECHNOLOGY
EDDS a Readily Biodegradable Chelant that can directly
replace EDTA and phosphonates
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Domestic Applications
In domestic applications, all the chelants are disposed via the drains to the
sewage system and then into watercourses. As EDTA is not biodegraded in
municipal waste plants, it all ends up in the water system. For this reason
there are concerns about the domestic use of EDTA. EDDS in contrast is
completely biodegraded/mineralised to carbon dioxide, water and nitrates in
the waste plant.
UK AWARDS FOR GREEN CHEMICAL TECHNOLOGY
Octel Performance Chemicals Page 6 of 10 UK GCT Awards Ver 1
Laundry Detergents
A solution of the tri-sodium salt of EDDS under the name Octaquest® E30
was initially developed for the laundry detergent market. This has been used
to replace phosphonates in this market. It has successfully been used since
launch in 1996 and in 2002, the plant passed the cumulative total of 10,000
tonnes produced - a significant milestone for any chemicals’ production.
EDTA is no longer used for domestic laundry detergents in Western Europe,
though it is present in other household detergents and 2,619 tonnes1 were
used in 1999.
Hard Surface Cleaners
EDTA is widely used in household, institutional and industrial cleaners 10,685
tonnes1 of EDTA were used in this market in 1999. Octaquest® E30 was
commercialised into this market during 2002 with product launches in the
Nordic area.
UK AWARDS FOR GREEN CHEMICAL TECHNOLOGY
EDDS a Readily Biodegradable Chelant that can directly
replace EDTA and phosphonates
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Personal Care
EDTA is extensively used in the personal care industry and can be found on
the ingredient list on many personal care product bottles. 756 tonnes1 of
EDTA were used in 1999. All the ingredients from these products ultimately
end up in the environment through the drain and sewage system.
EDDS ability to chelate with transition metal ions means that it is particularly
suitable for stabilising peroxide solutions for hair products. Transition metals
can also catalyse the oxidation of olefins leading to rancid smells and
discoloration that can be prevented by the use of chelates. Octaquest® E30
was commercialised with shampoo formulators in Europe during 2000 and
new customers are coming on stream.
EDDS acts as a potentiator for many common biocides used in personal care.
EDDS significantly enhances the effectiveness of biocides and can lead to
reductions in MIC (Minimum Inhibitory Concentration) of over 90%. This has
the potential to significantly reduce the levels of biocides used in personal
care products and the amounts of biocide released into the environment