Open AccessONE-POT-TWO-STEP SYNTHESIS OF BIOLUBRICANT BASE STOCK FROM RUBBER SEED OIL
Author(s) -
G.O . Madojemu,
E.A. Elimian,
M.C. Ejimadu,
C.O. Okieimen,
F. E. Okieimen
Publication year - 2020
Publication title -
bulletin of the chemical society of nigeria
Language(s) - English
Resource type - Journals
ISSN - 0795-2066
DOI - 10.46602/jcsn.v45i5.533
Subject(s) - epoxide , natural rubber , hydrogen peroxide , hydroxylation , lubricant , acid value , base oil , chemistry , fourier transform infrared spectroscopy , acetic acid , response surface methodology , vegetable oil , organic chemistry , central composite design , yield (engineering) , nuclear chemistry , materials science , chemical engineering , chromatography , catalysis , composite material , scanning electron microscope , biochemistry , engineering , enzyme
Biolubricant base stock was synthesized in this work from rubber seed oil in a one-pot-two-step process of epoxidation and hydroxylation. Rubber seed oil was extracted using a Soxhlet apparatus. The in situ epoxidation of the rubber seed oil with peracid (hydrogen peroxide and acetic acid) was analysed and optimized considering three process variables with their range of values given as temperature of 35-50 , time of 60-180 mins and mole ratio of hydrogen peroxide to acetic acid of 1:0.25-1:1 by applying the central composite design of response surface methodology. The ring opening reaction (hydroxylation) of the epoxide to polyhydroxylated oil (lubricant basestock) with ethanol was carried out using the optimum conditions obtained from the epoxidation process. The rubber seed oil, epoxide and lubricant basestock were characterized in terms of physico-chemical properties using standard methods and in terms of functional groups using Fourier Transform Infrared (FTIR) spectroscopy. Maximum epoxide content of 4.85% and maximum conversion of 71% of rubber seed oil to epoxide was achieved at a temperature of 50 , reaction time of 180 mins and 1: 0.39 mol/mol of hydrogen peroxide to acetic acid. The predicted values of the epoxidation process reasonably agreed with the experimental ones and model R-squared value of about 95% showed that response surface method can reasonably predict the epoxidation process using a quadratic polynomial model. There was 75% conversion of the epoxide to polyhydroxylated oil (biolubricant basestock), which represents a very high yield. The formation of epoxides and polyhydroxylated oil lead to modification (improvement) in the properties of rubber seed oil as confirmed by the physico-chemical properties and FTIR spectra analysis of the oil, epoxide and lubricant basestock. The study showed that chemical derivatives of rubber seed oils are an attractive, renewable, and ecofriendly alternative to mineral oils for lubricant formulations.