Page 130 - CW E-Magazine (25-2-2025)

Point of View

The challenge ahead is to scale this up. The present output of such sustainably produced seed accounts for just 5% of total crop and
the plan is to take the share of certified oils to 30% by 2030. This is a tall order, but one that must be addressed given the sustainability
mandates expected in about three years, first in European markets.

Making more use of oil locally
India currently produces much more castor oil than it can consume and needs to ship out most of it. Total availability (production + carryover)
in FY24 was about 860-mt, and as much as 650-kt was exported.

One reason to boost local consumption is that several derivatives serve applications that can be met through alternate chemistries or
products (often of petrochemical origin), and switches can happen. For example, the electrification of mobility through battery electric vehicles
could send prices of lithium-based greases (based on castor oil and lithium metal) to unaffordable levels, making room for alternatives such
as polyurea-based greases (that do not need castor oil).

Primary derivatives currently made in India include hydrogenated castor oil (HCO), dehydrated castor oil (DCO) and DCO fatty acids,
ethoxylated castor oil, Turkey Red Oil (TRO), methyl ricinoleate and 12-HSA. The secondary derivatives include alkyd resins, fatty amides,
undecanoic acid, heptaldehyde, sebacic acid & its esters, 2-octanol, polyols, etc. But the scale of manufacturing of these derivatives is small
and the industry has, at times, found it difficult to match the competitiveness of Chinese producers in global markets.

Speaking at a recent conference organised by the Sustainable Castor Association, Prof. M.M. Sharma, former Director, Institute of
Chemical Technology (ICT), and a renowned chemical engineer, stressed the importance of using the full chemical diversity of the oil
and retaining as many of its carbon atoms as possible in the derivative, rather than cleave to give fragments that have varying demands
that compromise the techno-economics of the process. This approach may even mean revisiting products that served well in the past
but have since been relegated to the background. He cited the case of TRO as a versatile surfactant made by the sulphation of castor
oil using concentrated sulphuric acid.

With the polyurethane (PU) industry – exemplified by the ubiquitous foam mattresses – expected to show strong growth in India and
sustainability pressures also mounting on it, there is a good case for increased use of castor-based polyols in it. Currently, the vast majority
of polyether polyols used come from propylene oxide of petrochemical origin. Castor-based PU find applications in areas such as biomedical
implants, coatings, cast elastomers, thermoplastic elastomers, rigid, semi-rigid & flexible foams, sealants, adhesives, etc.

Other derivatives for which local markets can be expanded include: ricinoleic acid and 12-HSA; ricinoleyl alcohol, which can be converted
to its disulphate and may be able to replace lauryl sulphate in cleaning products; heptaldehyde and its derivatives such as heptanoic acid
and heptyl alcohol; and sebacic acid and its esters (which find use as plasticisers and for polyamides).

One of the highest-value derivatives from castor oil is Nylon 11 – an engineering plastic – produced by cracking castor oil to produce
undecylenic acid, which is subsequently converted to the related amide and finally the polyamide. The value-addition that accrues is very
significant, but the marketing challenges here are formidable.

Although the growing popularity of ‘green’ fuels suggests production of castor-based biodiesel, caution is advised. Castor oil, with its
unique chemistry, is too valuable to be wasted as fuel. Instead, in a world where bio-based products are all the rage, there is much to be
gained by leveraging its chemical potential to the fullest!

Renewed focus of all stakeholders needed
Broadening the product slate and expanding the markets for derivatives will lay a solid foundation for a sustainable chemical industry
based on a renewable raw material that has little competition with food. The time has come for India to evolve a unified strategy to encompass
a ‘Castor Complex’ akin to the Malaysian efforts with palm. While the CSIR-Indian Institute of Chemical Technology at Hyderabad once had
a programme on valorising castor oil, it seems to have faded out and India today has little by way of publicly-funded research in this space.
This must also change!

At the upstream end, plant breeding is today a very sophisticated science, and further gains in castor seed yields can be made through
concerted efforts.
Ravi Raghavan

130 Chemical Weekly February 25, 2025

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