Page 189 - CW E-Magazine (21-11-2023)

Special Report

Castor oil-based chemicals & opportunities

for value-addition

n recent times, there has been a Properties HiManSHu SaXEna
notable surge in the use of vegetable Castor oil is a colourless or pale Assistant Manager – Operations
Ioils for producing a diverse range yellow, viscous, and transparent liquid TechSci Research
of eco-friendly chemicals and poly- that remains non-volatile, non-irritating, Email: himanshu.saxena@tech
mers, with the aim of reducing the and non-drying. It possesses specifi c sciresearch.com
environmental footprint when compared physical characteristics, including a TechSciResearch.com
3
to petroleum-based counterparts. density of 0.95–0.974 g/cm ; a freez- for chemical modifi cation and hold
Castor oil, being a renewable resource ing point of -10°C; a saponifi cation promise for its further development and
and a crucial foundational chemical, number of 180 mg potassium hydroxide utilisation.
has attracted growing interest, also as (KOH)/g; an iodine number of 82-90 mg
a raw material for creating bio-based iodine/g; and a hydroxyl number Chemical modifi cations
chemicals and polymers. These chemi- exceeding 155 mg KOH/g. Castor oil has garnered considered
cals derived from castor oil encompass global attention as a raw material for pro-
biodiesel fuels, lubricants, plasticizers, Castor oil has excellent storage ducing renewable alternative to petro-
and polyols, while the castor-oil-based stability and is nearly insoluble in most chemicals, making it a vital means to
polymers consist primarily of poly- petroleum hydrocarbon solvents, with reduce our reliance on oil, maintain
urethanes, polyesters, elastomers, and the exception of ethanol. The primary ecological balance, and promote rapid
cross-linked polymers. component of castor oil is the triglyceride, economic growth. The molecular struc-
which primarily comprises four types ture of castor oil, with its hydroxyl
The castor plant of fatty acids: ricinoleic acid (~66%); group and unsaturated double bonds,
The castor oil plant, scientifi cally oleic acid (~8%); palmitic acid (~8%), and is amenable to various chemical reac-
known as Ricinus communis, belongs linoleic acid (~6%). Moreover, castor oil tions, including hydrolysis, esterifi ca-
to the Euphorbiaceae family and stands out for its high hydroxyl and tion, cracking, epoxidation, amidation,
exhibits robust resistance to both acidic acyl content, compared to other vegetable and dehydration. These reactions can
and alkaline conditions. It demon oils, boasting a substantial total un- be harnessed to modify castor oil and
strates strong adaptability and is saturated fatty acid content, reaching create chemical products that can replace
extensively cultivated in India and as high as 88%. These active func- petrochemicals. Researchers have
China (with China ranking as the world’s tional groups render castor oil suitable focused on these properties to utilise
second-largest producer much behind castor oil as a raw material for producing
India). Castor oil is extracted from this a range of fi ne chemicals and polymer
invasive plant, which contains toxic materials such as heptanal, undecylenic
elements, namely ricin and ricinine, Others, acid, azelaic acid, 2-octanol, oil-based
650
found in its leaves and seeds. As ricin Gujarat, paint, and alkyd resins. Castor oil
is a water-soluble protein, it does not Andhra 2,371 and its processed derivatives fi nd
dissolve in castor oil. The toxicity of Pradesh & extensive applications in various aspects
castor seeds is eliminated when they Telangana, of modern life. Thorough research into
are exposed to temperatures exceed- 1,500 the adaptation and utilisation of castor oil
ing 70°C. People in some rural areas holds immense economic importance.
safely consume castor seeds because Rajasthan,
they fry them at high temperatures before 1,690 Chemicals and polymers derived
consumption. Globally, the annual from castor oil
production of castor oil has reached
500,000-tonnes. This non-edible oil Biodiesel
presents signifi cant economic advan- Fig. 1: State-wise yield of castor seeds in India Biodiesel is created through a
in 2021-22.
tages and has attracted widespread Others include Maharashtra, Karnataka, chemical process known as trans-
research interest. Tamil Nadu and Orissa esterifi cation, which transforms fats

Chemical Weekly November 21, 2023 189

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