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American Journal of Oil and Chemical Technologies; ISSN (online): 2326-6589; ISSN (print): 2326-6570 Volume 1, Issue 9, November 2013 Turpentine Oil Hydration using Trichloroacetic Acid as Catalyst N. Wijayati1,2*, H. D. Pranowo3, Jumina3, Triyono3 1. Student of Doctorate Program, Department of Chemistry, Universitas Gadjah Mada, Yogyakarta 2. Department of Chemistry, Semarang State University, Jl. Raya Sekaran Gunungpati Semarang 3. Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Yogyakarta Corresponding Author Email: [email protected] Abstract: Trichloroacetic acid (TCA) was used as catalyst for the hydration of α-pinene from turpentin oil using water as hydroxyl donor. The reaction was performed in batch reactor at 70oC, using aquous aceton as solvent. The TCA catalyst converted α-pinene into hydrocarbons, while the TCA catalyst was active and selective for producing alcohol, α-terpineol with selectivity of 87,56%. Keywords: Turpentine; Hydration; Terpineol; TCA 1. Introduction Turpentine is generally produceed in places having vast tracts of pine. Chemically, turpentine is a mixture of cyclic monoterpene hydrocarbons, C10H16, such as α-pinene, camphene. β-pinene and 3-carene being α-pinene the predominant constituent [1]. The chemical reactivity of turpentine varies with its composition but generally is the characteristic of α-pinene. α-pinene is known to react readily in the presence of acids through reactions involving either expantion to derivatives of bornane or fenchane, or ring opening to derivatives of p-memhane. Upon treatment with aquous mineral acids, complex mixtures are obtained resulting from isomerization and hydration [2-4]. The hydration of terpenes via acid catalysis is an important method for alcohol synthesis, and has several applications in the perfume and pharmaceutical industries. α-Terpineol, 4-terpineol and terpineol hydrate are from commercial viewpoints, the most interesting derivatives of α-pinene. α-Terpineol exhibits antimicrobial activity and is used for wound healing and insect bites [5-8]. 21 American Journal of Oil and Chemical Technologies; ISSN (online): 2326-6589; ISSN (print): 2326-6570 Volume 1, Issue 9, November 2013 Hydration and isomerization of the α-pinene to several alcohol or terpenic hydrocarbons have been studied since the 1940s. Román-Aguirre et al. [9] utilised oxalic and chloroacetic acid for the transformation of α-pinene and obtained conversion of 80% with selectivity of 70% for α-terpineol after 4 h but the dissolved acid had to be separated. Robles et al. [10] used HPW12O40 as catalyst and mixtures of acetic acid and water as solvent for hydrating limonene, b-pinene and a-pinene, obtaining selectivity to terpineol near to 30%, with 90% of a-pinene conversion after 3 h of reaction at 25oC. Pakdel et al. [11] used aqueous solutions of sulfuric acid as catalyst in the presence of acetone to obtain terpineol from crude sulphated pine oil, they reported 67% of selectivity to terpineol although conversion was not reported. The systems before mentioned need the manufacture of catalytic supports; nevertheless, diffusivity is altered in the course of the reaction, or they present environmental problems by the disposition of the used homogenous catalysts.. The objective of this work is to study the role of trichloroacetic catalyst to hydration α-pinene to terpineol using water as the hydroxyl group donor. 2. Experimental Section: 2.1. Materials α-Pinene was obtained from isolation of turpentine oil. The trichloroacetic acid (TCA), aceton and deionized water were e-Merck products. The reagents were not purified before its use. 2.2. Instrumentation Analysis of the reaction products was performed by Gas Chromatography (GC) (Hewlett Pacard 5890 Series II equipped with flame ionization detector/FID). The column used was HP5 (% Phenyl Methyl Siloxane). The temperature of the column was adjusted to be 70oC for 5 min and then increased to 280oC by 10oC/min. The carrier gas used was helium (He) (0,1µL/min flow). The injection and detection temperatures were set to be 280 and 300oC, respectively and the split mode was 1/100. The various components were characterized by FTIR and GC-MS instrument. 2.3. Procedure The catalytic tests were performed in a 100-cm3 three-necked-glass reactor with condenser and thermocouple. The reactor was submerged in thermostatic bath with silicone oil and magnetic stirring. In batch experiment, 3.6 mmol of α-pinene, 18 mmol of water and 10 mL of aceton were first placed. After heating to the desired temperature, 32 mol of the trichloroacetic acid catalyst was added. Aliquots were extracted with a micropipette and immediately analyzed with GC. 3. Result and Discussion: 3.1. Effect of catalyst Acids catalyze the hydration reactions of alkenes in aqueous solution. The acid transfers a proton to double bond of the alkene, forming an intermediary carbocation that reacts with water to form a protonated alcohol. The loss of H+ from the protonated alcohol generates the neutral product and the recovery of the catalyst. In the hydration of terpenes, a variety of products may be obtained 22 American Journal of Oil and Chemical Technologies; ISSN (online): 2326-6589; ISSN (print): 2326-6570 Volume 1, Issue 9, November 2013 depending on the catalyst and reaction conditions (Fig 1). To study the effect of acidity strength and organic/inorganic nature of trichloroacetic acid on the pinene hydration, reaction test were made at 70oC with reaction time of 30 min. + H+ Hydration -H+ OH α-pinene Isomerization α-terpineol camphene limonene terpinolene Figure 1. Hydratian reaction α-pinene using trichloroacetic catalyst The hydration of α-pinene with trichloroaceticacid catalyst leads to a complex mixture of monoterpenes (alcohols and hydrocarbons). When the hydration reaction is carried out in the presence of water with acid catalysts, in addition to the products mentioned above, alcohols such as α-terpineol. Alpha-terpineol, an important monoterpenic monocyclic alcohol, is industrially obtained through the hydration of α-pinene with an aqueous mineral acid, giving rise to the cisterpene hydrate, followed by a partial dehydration to α-terpineol [2]. The formation of these compounds supports the above mentioned, and trichloroacetic acid could promote the water/pinene interaction, so protons at organic phase promote mainly pinene rearrangement isomerization like in the isomerization process of pinene to produce camphene. 23 American Journal of Oil and Chemical Technologies; ISSN (online): 2326-6589; ISSN (print): 2326-6570 Volume 1, Issue 9, November 2013 100 90 80 70 C and S (%) Cα-pinene S α-Terpineol 60 50 40 30 20 10 0 30 60 120 240 time, min Figure 2. Conversion (C) and Selectivity (S) over trichloroacetic catalyst vs. Time As shown in Fig. 2 and Table 1, the conversion obtained using trichloroacetic acid as catalyst was 88.20% and the selectivity to terpineol was 87.85%, this result is notable for industrial purposes, other advantages with this catalyst are the absence of chlorinated by-products, and the capability to recover catalyst by simple recrystallization. Trichloroacetic acid is miscible with pinene and also soluble in water, due to these two factors, this catalyst, besides the formation of the proton to form the carbocation, favors the transfer of OH- to organic phase and as a result, hydration yield is the highest of the studied catalysts [9]. 24 American Journal of Oil and Chemical Technologies; ISSN (online): 2326-6589; ISSN (print): 2326-6570 Volume 1, Issue 9, November 2013 Table 1. Turpentine oil hydration using TCA catalyst conversion Selektivity, S (%) time (min) α-pinene (%) camphene limonene terpinolene terpineol others 30 88,21 1,80 6,21 2,87 87,56 1,55 60 89,73 9,14 22,47 9,31 23,10 10,35 120 90,74 9,59 23,95 8,44 22,71 35,31 240 94,53 7,52 25,00 7,80 25,05 34,63 3.2. Effect of temperature Fig 3 shows the effect of temperature on the conversion, plot under otherwise similar conditions. Selectivity of terpineol increases significantly with an increase in temperature. Hydration of α-pinene is an exothermic reaction and the equilibrium shift in the reverse direction with a rise in temperature. 100 Concentration (%) 80 60 α-Pinene α-Terpineol 40 others 20 0 50 60 70 Temperature, oC Figure 3. Efect of temperature for turpentine oil hydratioan using trichloroacetic catalyst 25 American Journal of Oil and Chemical Technologies; ISSN (online): 2326-6589; ISSN (print): 2326-6570 Volume 1, Issue 9, November 2013 4. Conclusion The chloroacetic acid catalyst was active and selective for producing alcohols, with a conversion of 88,21% and showed 87,56% selectivity for α-terpineol at 30 min. The good results were due to its strong acidity during reaction and its easy separation from reaction products. The yield obtained by using this catalyst was interesting for industrial application. 5. Acknowledgements: The authors would like to thank to Directorate General of Higher Education (DIKTI), Department of National Education Republic Indonesia for the Fundamental Research grant. 6. References: [1] Avila, M. C., Nora A. C., Castellon E. R., Lopez A. J., 2010, J.Mol.Catal. A: Chemical, 322,(1-2),:106-112. [2] Vital J., A.M. Ramos, I.F., Silva, H. Valente., J.E., Castanheiro, 2001, Catal. Today, 67, 217-223 [3] Castanheiro J.E., I.M., Foseseca, A.M. Ramos, R. Oliveira, J.Vital, 2005, Catal.Today, 104, 296-304. [4] Mochida T., Ryuichiro O., Naoto H., Yuichi K., Toshio O., 2007, Micropor.Mesopor. Mat., 101: 176-183 [5] Bhatia, S.P., 2008, Food.chem.toxicol., 46 : 5275-5279. [6] Martino L.D., Vinzenco D.F., Carmen F., Enrico M., and Felice S., 2009, Molecules, 14, 2735-2746. [7] Moreira,M.R., Cruz, G.M.P., Lopes, M.S., Albuquerque, A.A.C. dan Cardoso, J.H. L., 2001, J.Med.Biol.Res., 34: 1337-1340 [8] Bagheri S. M, Amirhossein S, Ahmad R. G., Soodabeth S, Maryam M, and Mehrdad I, 2010, Pharm. Biol., 48(3): 242-2463. [9] Roman-Aguirre. M.R., De la Torre-Sáenz, Wilber A.F., A. Robau-Sánchez, A. AguilarElguézabal, 2005, Catal. today, 107-108 :310-314 [10] Robles-Dutenhefner, Patricia A.,, Kelly A., da Silva, M. Rafiq H. S., Ivan V. Kozhevnikov, Elena V. G., 2001, J. Mol. Catal A: Chem, 175, 33-42. [11] Pakdel, H., Sharron, S., and Roy, C., 2001, J. Agric. Food. Chem., 49, 9, 4337–4341. 26