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Thursday, February 2, 2017

TECH SPECIAL ....Catalysts: Challenging new frontiers

Catalysts: Challenging new frontiers

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!

- Ravi Raghavan CHWKLY 24JAN17

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