Chemical modification of Jatropha curcas and Thevetia peruviana oil as starting materials for chemical industry

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1 AMERICAN JOURNAL OF SCIENTIFIC AND INDUSTRIAL RESEARCH 2015,Science Huβ, ISSN: X, doi: /ajsir Chemical modification of Jatropha curcas and Thevetia peruviana oil as starting materials for chemical industry Jabar Jamiu M., Lajide Labunmi, Adetuyi Abayomi O., Owolabi Bodunde J. and Owokotomo Ignatius A. Organic and Polymer Research Laboratory, Chemistry Department, the Federal University of Technology, P.M.B 704 Akure, Ondo State, Nigeria *Correspondence; Phone number: ABSTRACT The impart of time as variable parameter on epoxidation and hydroxylation of Jatropha curcas (JCO) and Thevetia peruviana oil (TPO) by in-situ epoxidation and hydroxylation was investigated. The iodine values of modified JCO/TPO were lower than that of unmodified JCO/TPO due to substitution of carbon to carbon double bonds by oxirane and hydroxyl functional group in epoxidized and hydroxylated oil respectively. These were confirmed by FT-IR spectra of modified JCO and TPO that showed presence of oxirane functional group at 837 and 843 cm -1 and disappearance of carbon to carbon double bonds at 3080 and 3050 cm -1 in epoxidized JCO and TPO oil respectively. Equally, FT-IR spectra of hydroxylated JCO and TPO showed disappearance of oxirane function group and increase in -OH broad peaks at 3459 and 3472 cm -1 indicating conversion of epoxides to polyols. The percentage oxirane, which is a confirmation and measurement of the degree of epoxidation increased with increase in time of epoxidation and decreased with increase in time of hydroxylation reaction, while hydroxyl value increases with increase in time of hydroxylation reaction. Keywords: Epoxidation, FT-IR spectra, Hydroxylation, Iodine value, Oxirane INTRODUCTION Plant and animal oils are natural renewable materials which differ in structure and unsaturation. Vegetable oil is a class of plant oil that is abundant, inexpensive, biodegradable, environmental friendly and offer different degree of unsaturation depending on nature of the plant (Petrovic, 2010). Vegetable oil, such as Jatropha curcas, Thevetia peruviana, jojoba, karanja, soybean, castor, linseed, okra seed oil etc are considered non reactive chemical materials that can be made reactive through chemical modification (Saurabh et al. 2012). J. curcas (JCO) and T. peruviana oil (TPO) are triglycerides, which contain pamitoleic, oleic, linoleic and erucic acid containing one, one, two, three and one double bonds between two carbon atoms respectively as unsaturated fatty acids present in the oils. These C=C bonds are the reactive sites for chemical modification in JCO and TPO. Various chemical modifications with double bonds (reactive sites) of these vegetable oils can be done, the common ones that can make them valuable starting materials in chemical industry are epoxidation and hydroxylation (Goud et al. 2006; Liting et al. 2009). Epoxidation of fatty acids is a reaction of a carbon to carbon double bond with active oxygen to form a three membered oxirane ring or epoxide group. The established methods of epoxidation are epoxidation by Conventional method, epoxidation using acid ion exchange resin (AIER), epoxidation using enzymes, epoxidation using metal catalyst and other Systems (Dinda et al. 2008). Hydroxylation is the conversion of epoxyl group to hydroxyl group through cleavage of oxirane ring in epoxide. The hydroxylation reaction using acid catalyst follows substitution nucleophilic reaction type 1 mechanism and leads into formation of carbocation due to the action of acid on epoxide and finally form polyol by the reaction of the nucleophile on carbocation (Solomon, 1992). The detailed reactions involved in each step are summarized in scheme 1-3 below:

2 SO CH 3 COOH + H 2 O 2 H2 4 CH 3 COOOH + H 2 O Scheme 1: Formation of peroxyacetic acid peroxyacetic acid C H 3 C O O O H + C H O unsaturated oil Scheme 2: In-situ epoxidation of the unsaturated bond in the oil epoxidized oil O C H H + H 2 O O C H 124 H 2 O epoxidized oil carbocation 1,2- diol Scheme 3: Hydroxylation of epoxide The goal of the current study is to quantify the influence of reaction time on the conversion of T. peruviana and J. curcas oil to epoxidized and hydroxylated products for use as precursors in chemical industry. EXPERIMENTAL Materials: T. peruviana and J. curcas seeds were collected from Akure south local government area of Ondo state, Nigeria in March The seed coats were removed from the seeds using a small head hammer. The seeds were then sun dried for 15 days, followed by oven drying at 40 o C to obtain moisture free seeds and ground with an electric blender (century). Vegetable oil was extracted from ground seeds by cold extraction method. After the extraction, oil was separated from the extracting solvent (petroleum ether) by simple distillation on rotary evaporator (Jabar, 2015). Methodology Physicochemical properties of T. peruviana (TPO) and J. curcas oils (JCO): Colour, density, specific gravity, refractive index, acid value, free fatty acid, O H C H O H saponification value and iodine value of the TPO and JCO were determined according to standard methods (Firestone, 1998). Chemical modification of T. peruviana (TPO) and J. curcas oils (JCO): Epoxidation of JCO and TPO was carried out at 50 o C using peroxyacetic acid prepared in situ via reaction between calculated amount of 30 % aqueous hydrogen peroxide as oxygen donor and glacial acetic as oxygen donor (Okieimen et al. 2002), in mole ratio 1:1.8:0.5 oil:h 2 O 2 :CH 3 COOH in presence of conc. H 2 SO 4 (2 % of total mole of H 2 O 2 and CH 3 COOH). In this modification reaction, a known amount of JCO/TPO was placed in a 500 ml round flask containing an adequate amount of glacial acetic and conc. H 2 SO 4. The flask equipped with a 3 neck glass quick fit, reflux condenser, thermometer and mechanical stirrer was allowed to attain reaction temperature while stirring for 30 min in a thermostatic heating mantle and hydrogen peroxide was added gradually for the next 30 min. A medium stirring rate was used to finely disperse the oil in the reaction mixture. The reaction

3 was monitored by withdrawing aliquot of the reaction mixture at 1 h interval (taking time of complete addition of H 2 O 2 as zero hour) into a separating funnel containing warm distilled and wash successively with warm water until it was acid free. The resulting epoxidized JCO/TPO was dried over night using a dried magnesium sulfate and oxirane oxygen content, iodine value, percentage yield and relative iodine conversion were determined using equations below:. (1) Relative conversion to oxirane (RCO) = OO e 100 %. (2) OO t Where: OO e = experimentally obtained oxirane oxygen content in g/100gm oil sample OO t = theoretical maximum oxirane oxygen content in g/100gm oil sample IV o = Initial iodine value of the oil sample IV t = Iodine value of the oil sample at a particular time OO t can be determined from expression from expression in equation (3). OO t = IV o /2A i 100A o (3) (IV o /2A i )A o Where: A i = Atomic weight of iodine = amu A o = Atomic weight of oxygen = 16.0 amu The hydroxylation reaction was equally carried out using mixture of epoxidized JCO/TPO, distilled water and tertiary butanol in mole ratio 1:2:4 of epoxide: water: tert- butanol in presence of conc. H 2 SO 4 as catalyst, the mixture in a round bottom flask equipped with reflux condenser, thermometer and a 2 cm diameter four bladed mechanical stirrer. The hydroxylation reaction was carried out at temperature 80 o C on a heating mantle for 6 h and the reaction was monitored by withdrawing aliquot of the reaction mixture at 1 h interval into a rotary evaporator that distilled off the aqueous phase and tert- butanol from the polyol. At the end of the hydroxylation reaction, the products were characterized using standard methods (Firestone, 1998). The epoxidation and hydroxylation reactions of JCO and TPO were confirmed using FT-IR analysis. RESULTS AND DISCUSSION The physicochemical properties of chemically modified and unmodified JCO and TPO presented in Table 1 are in agreement with those of conventional 125 oil such as soybean, linseed, African oil bean and rubber seed oil used in industrial applications (Awolola et al. 2010). The iodine values of JCO and TPO are higher than those of epoxidized J. curcas (EJCO), epoxidized T. peruviana (ETPO), hydroxylated J. curcas (HJCO) and hydroxylated T. peruviana oil (HTPO) because they contain higher degree of unsaturation that was reduced due to the substitution of carbon to carbon double bonds by oxirane group in EJCO and ETPO and hydroxyl functional groups in HJCO and HTPO (Dinda et al. 2008). The saponification values of HJCO, HTPO, EJCO and ETPO are higher than those of JCO and TPO because of high degree reduction in unsaturation nature of the JCO and TPO oil by hydroxylation and epoxidation process (Okieimen et al. 2005). The effect of the variation in time of epoxidation and hydroxylation reaction on epoxide and polyol of JCO and TPO were examined. The results of epoxidation

4 reaction were presented in Table 2, while Table 3 presents results on hydroxylation reaction. The oxirane oxygen content (OO e ) of the epoxidized oil was monitored for period of 6 h at an hour interval. It can be seen that a gradual increase in OO e occur till 5 h of epoxidation before decrease in OO e occur at sixth hour of reaction. This deviation from linearity of the graph of OO e Vs time t (Fig. 1) observed at sixth hour of reaction can be attributed to ring opening reaction that may occur from side reactions in peroxyacetic acid or, and/ epoxide formation. This observation agreed with Goud et al. (2006), in epoxidation of karanja oil by H 2 O 2 and Ikhuoria and Dadson (2007), in epoxidation and hydroxylation of Africa oil bean seed oil. Table 2 equally shows that relative conversion to oxirane (Y) is less than iodine conversion of double bond (X), this observation further support the possibility of oxirane ring opening due to the side reactions at higher time of epoxidation. Decrease in iodine values of JCO and TPO from 1 to 6 h epoxidation reaction confirmed the conversion of C=C double bonds to oxirane ring. The increase in Hv and decrease in OOc from 1 to 6 h hydroxylation reaction of JCO and TPO (Tables 3 and 4) are indications of ring opening reaction of oxirane group from epoxide to 1,2- diol of polyol, that was confirmed by FT-IR analysis. The FT-IR spectra of raw (unmodified), epoxidized and hydroxylated J. curcas and T. peruviana oil are shown in Fig. 2 and 3 respectively. From the spectra it is clear that the peak related to carbon to carbon double bonds from unmodified J. curcas and T. peruviana oil at 3080 cm -1 and 3050 cm -1 respectively disappeared on epoxidation, the epoxy groups were found in epoxidized J. curcas and T. peruviana oil at 837 cm -1 and 843 cm -1 respectively indicating that carbon to carbon double bonds were turn into epoxy groups and a little broad peak appearing at 3459 cm -1 and 3472 cm -1 in EJCO and ETPO respectively is an indication of hydrolytic cleavage of little part of oxirane groups to hydroxyl group. These observations which are confirmation of epoxidation of JCO and TPO agreed with Derawi and Salimon (2010), in Optimization on epoxidation of palm olein by using performic acid and Saurabh et al. (2012), in studies on synthesis of biobased epoxide using cotton seed oil. The disappearance of twin peak at 837 cm -1 and 843 cm -1 and appearance of new broad peak at 3415 cm -1 and 3380 cm -1 in HJCO and TPO oil respectively are confirmations of conversion of reactive oxirane group to hydroxyl group in hydroxylation of EJCO and ETPO, this observation is in agreement with Awolola et al. (2010), in refining, modification and characterisation of tobacco seed (Nicotiana tobacum) oil for its improved potentials for industrial use. All other bands in all the spectra have similar characteristics with predominant bands at 1368, 1375 and 1320 cm -1, 1367, 1373 and 1320 cm - 1 corresponding to C-H bond in unmodified and modified JCO and TPO. The presence of C-H 2 bond appeared at cm -1 in the spectra of unmodified and modified JCO and TPO, while peak at cm -1 confirmed presence of carbonyl group (C=O) in all the spectra. These observations agreed with Adewuyi et al. (2011), in solvent free hydroxylation of the methyl esters of Blighia unijugata seed oil in the presence of cetyltrimethylammonium permanganate. 126

5 Table 1: Physicochemical properties of unmodified and modified J. curcas and T. peruviana oil Properties JCO TPO EJCO ETPO HJCO HTPO Oil yield (%) Colour yellow golden whitish whitish bright bright yellow yellow yellow yellow yellow Specific 0.907± ± ± ± ± ±0.00 gravity Moisture 0.091± ± ± ± ± ±0.00 content (%) ph 5.30± ± ± ± ± ±0.06 Viscosity (mpa. s) Refractive index Acid 12.50± ±0.53 ND ND ND ND value (mg KOH/g) S.V ± ±1.83 ND ND ± ±0.43 (mg KOH/g) I.V ± ± ± ± ± ±0.07 (mg KOH/g) Key: ND = Not determined, JCO = Jatropha curcas oil, TPO = Thevetia peruviana oil, EJCO = Epoxidized Jatropha curcas oil ETPO = Epoxidized Thevetia peruviana oil, HJCO = Hydroxylated Jatropha curcas oil, HTPO = Hydroxylated Thevetia peruviana oil. 127

6 Table 2: Properties of epoxidized J. curcas and T. peruviana oil Epoxidized J. curcas oil Epoxidized T. peruviana oil Time OOe Y X EF OOe Y X EF (h) (%) (%) (%) (%) (%) (%) (%) (%) ± ± ± ± ± ± ± ± ± ± ± ± Key: t = Time of epoxidation reaction OOe = Oxirane oxygen content Y = Relative conversion to oxirane X = Iodine conversion EF = Epoxy functionality Table 3: Properties of hydroxylated J. curcas oil t(h) SV 1 (mg KOH/g) SV 2 (mg KOH/g) HV (mg KOH/g) OO c (%) HF ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Key: HV= Hydroxyl value of the oil SV1 = Saponification value of the oil before acetylation SV2 = Saponification value of the oil after acetylation OOc = Oxirane oxygen content of the hydroxylated oil and; HF = Hydroxyl functionality Table 4: Properties of hydroxylated T. peruviana oil t(h) SV 1 (mg KOH/g) SV 2 (mg KOH/g) HV (mg KOH/g) OO c (%) HF ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

7 Fig. 1: Change in % oxirane with reaction time Fig. 2: FT-IR spectra of TPO, ETPO and HTPO 129

8 Fig. 3: FT-IR spectra of JCO, EJCO and HJCO Conclusion: The study shows the possibility of obtaining industrial precursors from ornamental garden plants; J. curcas and T. peruviana oil. These renewable materials can serve as alternative to the use of petroleum resource in chemical and allied industries. REFERENCES Adewuyi, A., Oderinde, R.A., Rao, B.V.S.K., Prasad, R.B.N., Nalla, M. (2011). Solvent free hydroxylation of the methyl esters of Blighia unijugata seed oil in the presence of cetyltrimethylammonium permanganate. Chem. Central J. 5: Awolola, V.G., Ogunniyi, D.S., Oluwaniyi, O.O. (2010). Refining, modification and characterization of tobacco seed (Nicotiana tobacum) oil for its improved potentials for industrial use. Nig. J. Pure and Appl. Sci. 23: Derawi, D., Salimon,J. (2010). Optimization on epoxidation of palm olein by using performic acid. E-Journal of Chem. 7(4): Dinda S., Patwardhan A.V., Goud V.V., Pradhan, N.C. (2008). Epoxidation of cottonseed oil by aqueous hydrogen peroxide catalysed by liquid inorganic acids. Bioresource Technol. 99 (9): Firestone, D. (1998). Official methods and recommended practices of the American oil Chemist Society, 5 th Edn., AOCS, Champaign, 11 (USA) Goud, V.V., Patwardhan, A.V., Pradhan, N.C. (2006). Studies on the epoxidation of mahua oil (Madhumica indica) by hydrogen peroxide. Bioresource Technol. 97: Ikhuoria, E.U., Dadson, G.E. (2007). Epoxidation and hydroxylation of African bean (Pentaclethra macrophylla) seed oil J. Chem. Soc. Nig. 32 (2): Jabar, J.M. (2015). Synthesis and characterization of natural fibre reinforced bio-base polyurethane foam. Ph.D Thesis, FUTA Liting, H.Y., Bo, L., Chengsuang, W., Guang, S. (2009). Synthesis and characterization of the different soybased polyols by ring opening of epoxidized soybean oil with methanol, 1,2 ethanadiol and 1,2 propanediol. J. Am. Oil Chem. Soc. 86: Okieimen, F.E., Bakare, I.O., Okieimen, C.O. (2002). Studies in the epoxidation of rubber seed oil. Ind. Crops Prod. 15: Okieimen, F.E., Pavithran, C., Bakare, I.O. (2005). Epoxidation and hydroxylation of rubber seed oil: One pot multi-step reactions. European J. Lipid Sci. and Technol. 107: Petrovic, Z.S. (2010). Polymers from biological oils. Contemporary Materials 1: Saurabh,T., Patnaik M., Bhagat S.L., Renge V.C. (2012). Studies on synthesis of biobased epoxide using cotton seed oil. IJAERS 1 (2): Solomons, T.W.G. (1992). Organic Chemistry, 5 th edn, John Wiley and Sons, Inc, New York 130