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Catalysts: Challenging new frontiers
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Catalysis
is at the core of chemical transformations, and the impact catalysts make go
far beyond the chemical industry. From cleaning up emissions of noxious gases
from internal combustion engines to enabling stereospecific chemical
transformations that enable just one desired configuration of optically
active molecules to be made, catalysts have a major role to play.
Indeed,
catalysts are understated achievers – the size of the global catalyst
business is hardly representative of the wide impact these functional
chemicals have. According to some estimates, as much as 90% of all chemical
manufacturing processes use some catalyst or the other. One will be hard
pressed to offhand recollect chemical processes in which no catalysts are
used!
Petroleum industry & catalysts: the quest for cleaner fuels
Process
catalysts that serve the petroleum industry account for a significant chunk
of the global catalyst market, but growth is now mainly in the developing
economies, including India. In these economies, energy demands are still
growing and investments in new refining capacity are needed to keep pace with
needs. The new refineries being built often have complex configurations, with
several secondary and tertiary processing steps – all of which need some
catalyst or the other.
The
largest refinery catalyst segments in terms of value are hydrotreating and
catalytic cracking, while the largest-volume products are alkylation
catalysts. Upgradation of fuel standards is an important driver. As India
upgrades its fuel quality from Euro IV to Euro VI –
leapfrogging an intermediate generation – refiners will need to make
significant investments in desulphurisation technologies, for example, to
bring down the level of sulphur in fuels. This will provide a large business
opportunity for catalyst companies.
Catalysts for polymerisation: enabling functionality and improving
sustainability
In
the petrochemical industries, the biggest catalyst market is for
polymerisation, and a variety of systems are deployed to obtain the right
configuration of polymers with desired functional performance. Today’s
catalysts allow production of resins that have a far lower material
footprint, without complicating processability in existing infrastructure or
performance in the intended application. Bottles and films made from advanced
resins are not just lighter and thinner, but come with additional benefits
such as easier recyclability and better performance.
Enabling a ‘greener’ chemical industry
In
the broader chemical industry, the needs to improve process efficiencies
& selectivities and to reduce the environmental footprint continue to
drive catalyst innovation and demand. Fine chemicals and pharmaceuticals
production, in particular, suffer from a heavy environmental footprint and
‘green chemistry and engineering’ principles have great relevance. Current
manufacturing methods more often than not involve multi-step synthesis, in
batch mode, with complex work-up at each stage. There are several efforts to
make these processes environmentally more benign by telescoping steps, making
them continuous and even scaling down (to micro-reactor scale) to make them
safer. All of these will require significant inputs from catalysis.
Defunctionalising biomass
The
utilisation of biomass for making fuels, chemicals and materials is another
hot area of research with several efforts ongoing. Defunctionalising the
constituents of biomass to simpler chemicals while technically challenging,
is an opportunity to lay the platform for a chemical industry based on
renewable carbon, rather than depleting petroleum. The utilisation of carbon
dioxide as a resource for fuels and chemicals is energetically and
thermodynamically challenging and can only be sustainably achieved with
catalysts and deployment of carbon-free energy.
Catalysts and the environment
The
environmental benefits of catalysts are nowhere as apparent than in the
three-way end-of-pipe exhaust gas treatment systems fitted on almost all
modern two-, three- and four-wheelers. These systems clean up emissions of
unburned hydrocarbons and oxides of carbon & nitrogen, besides trapping
particulate matter widely known to cause harm especially to the respiratory
system. Legislation drives the pace at which these markets grow, and this is
another significant growth opportunity in India. Companies such as BASF,
Johnson Matthey and Mitsui are ramping up capabilities to serve the demand
likely to emerge as India tightens emission norms.
Better understanding of the underlying science
For
long the development of catalysts was largely by trial and error. But with
better understanding of the underlying science, the availability of
instrumentation to characterise materials, and better computational
capabilities, a more systematic effort at developing novel catalysts is now
possible. Capabilities now exist to ‘see’ at the nano- and molecular levels,
and to visualise catalysts in action in real time (rather than just in
models). All this is permitting precise tailoring of catalytic properties, as
well as providing an unprecedented ability to predict catalyst performance
during use.
At
the same time, combinatorial chemistry and high-throughput screening using
miniaturized reactor systems are making it possible to evaluate thousands of
options and iterate to the most desired at time-scales unthinkable a decade
ago. The flip side, however, is that these approaches need expensive
equipment that are beyond the affordability of but a few.
Catalyst
development programmes are typically interdisciplinary, orchestrating teams
of chemists, physicists and increasingly biologists. They have also become
more collaborative – involving industry, academia and research laboratories
with complementary skills. There is now wide recognition that much can be
learnt from natural systems – that carry out complex transformations using
biocatalysts (enzymes) at ambient conditions of temperature and pressure.
Mimicking processes in nature – for example, photosynthesis – is amongst the
hottest areas of research today, and breakthroughs here could have
significant impact not just on foods, but also energy and chemicals. The
domain of organo-catalysis – deploying small, cheap and readily available
molecules – instead of bio-molecules such as enzymes, is another fast-growing
frontier of catalytic science.
India’s catalyst community
India
has a vibrant catalyst community centred in about a dozen academic
institutions; a handful of industrial research laboratories that are part of
the CSIR system; leading petroleum refining and petrochemical companies; and
the world’s leading catalyst companies. Refining companies such as Reliance
Industries Ltd., Indian Oil Corporation and Hindustan Petroleum Corporation
Ltd. have ramped up their own internal capabilities in catalyst research, and
also partnering with research laboratories. There is growing recognition that
catalyst expertise is key to enhancing ones competitive position in a
challenging market environment – a welcome deviation from earlier beliefs
that technologies can be brought for the asking and deployed.
Industrial
research laboratories that have active programmes in catalysis include the
Indian Institute of Petroleum (IIP), National Chemical Laboratory (NCL), and
the Indian Institute of Chemical Technology (IICT). Their focus is somewhat
different, though there are commonalities. IIP, as the name suggests, has an
emphasis on petroleum and has some notable achievements in developing
catalysts and processes for conversion of heavy petroleum fractions to the much-needed
LPG, gasoline and middle distillates. NCL, again as would be expected, has a
broader spectrum of interests – spanning refining, petrochemicals, commodity,
fine & speciality chemicals. A handful of academic institutes, including
Mumbai’s Institute of Chemical Technology, have also made some notable
contributions to understanding the fundamental science of some processes, and
nurtured their deployment in industry.
Miles to go!
There
are many conquests yet to made as far as chemical transformations go and
catalysis will be key to make them happen. Some of the grand challenges
include: the fixation of nitrogen (through something other than the
energy-intensive Haber-Bosch process); the selective activation of the inert
C-H bond (without over-oxidising the rest of the organic molecule); the
photo-catalytic splitting of water (using renewable energy); and finding
replacements for expensive inert metals that are omnipresent in today’s
catalytic system. Success in one or more of these will have wide ramifications
for society.
The
central role of catalysis in chemical transformations is here to stay even as
it challenges new frontiers!
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- Ravi
Raghavan CHWKLY 24JAN17
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