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A new route to high-purity isobutene
A joint first-place finish
Research can be extremely practical. Experts from four Evonik business and service units pooled
their expertise and within a short time developed a new process for producing high-purity iso -
bu tene on an industrial scale. Their work is an outstanding example of how high-tech simulation
and experimental knowledge, cost- and eco-efficiency, basic research, and practical application
can be ideally combined.
[ text Dr. Thomas Quandt, Dr. Dirk Röttger, Dr. Wilfried Schmidt, Dr. Markus Winterberg, Dr. Horst­Werner Zanthoff ]
Frequently, CHemiCal researCH takes place quite far from
the tough production environment—in laboratories, pilot plants,
and, increasingly, on the computer in online databases and
li braries. Thereby it is generally accepted that converting research
results into practice is a difficult and tedious process that
often fails halfway through.
Experts from four Evonik business and service units have
now again proven that it can also be a different experience. The
team, which comprises a variety of specialists, developed and
tested a new process for producing high­purity isobutene and
implemented it in two commercial­scale plants in Antwerp and
Shanghai in just a few years. The key to their success? Chemists,
process engineers, catalyst developers, plant engineers, and
mark eting experts combined their expertise, with research, development,
design, and product marketing occurring largely at
the same time. By meshing the individual steps tightly—from the
initial idea to the construction of the commercial­scale plants—
they were able to develop an economical and efficient production
process that not only supplies high­purity isobutene, but
also produces less waste and consumes less energy than conventional
processes.
In Marl and Antwerp, the C4 Chemistry Business Line operates
an integrated production network that obtains various chem­
elements34 Issue 1|2011
icals from C4 crack, including methyl tert­butyl ether, or MTBE.
MTBE, which is known to car drivers as an antiknock additive, is
the central component in the new process. Evonik manufac tures
over 500,000 metric tons of the substance each year, mak ing it
one of the company‘s highest­volume products.
The starting material for the C4 network is C4 crack, a hydrocarbon
fraction that occurs as a byproduct of ethylene and propylene.
Typically, it consists of 20 to 28 percent isobutene, 14 to
20 percent 1­butene, and other marketable C4 hydrocarbons,
such as butadiene, 2­butenes, isobutane and n­butane. Because
isobutene and 1­butene display nearly identical physical properties,
they cannot be separated through distillation or extraction.
Instead, chemists rely on a trick: They convert isobutene into an
ether that can be easily separated through distillation, owing to
the significantly higher boiling point of the other hydrocarbons.
If methanol is used in this conversion, MTBE is the resulting
ether. 333
The new process
for producing isobutene
in Antwerp has been
up and running since
October 2010