Hydrogenation of Some Vegetable Oils by Scrap Automobile Catalyst

Some vegetable oils were hydrogenated with scrap automobile catalyst (SAC) as a catalyst. e optimum reaction conditions (solvent, reaction time, and catalyst amount) were determined. Our results showed that the linoleic acid was reduced to elaidic acid in the sun�ower oil. is procedure not only gives high yields but also allows recycling of automobile wastes as a catalyst in organic reactions and is representative of green chemistry.


Introduction
Hydrogenation of fats and oils is a very important operation in the industrial process of producing vegetable tallow, vegetable fats, margarines, and starting components for the cosmetic and chemical industry such as emulsi�ers, soaps, creams, pastes, and similar substances [1].ere are two main reasons why hydrogenation is important to the industry.e �rst is increasing the stability of the oil.Highly unsaturated oil is susceptible to autoxidation, thermal decomposition, and other reactions that a�ect the �avor.Conse�uently, it is desired to partially hydrogenate the oil to improve shelf life.e second reason to partially hydrogenate vegetable oil is to improve its utility.For most products, such as shortenings, margarines, or confectionery fats, the desired soening and melting characteristics correspond to oils that are partially hydrogenated.e choice of catalyst to use for hydrogenation greatly a�ects the properties of the �nal product [2].
In continuation of our studies on the development of novel heterogeneous synthetic methodologies [11][12][13][14], we have achieved a novel procedure for the hydrogenation of sun�ower oils catalyzed by scrap automobile catalyst (SAC) which was used for the hydrogenation of carbon-carbon double bonds in our previous study [15].e lifetime of catalytic converters is limited and thus their recycling is crucial.Catalytic converters consist of a ceramic substrate coated with aluminum oxide (Al 2 O 3 ) and other rare earth oxides, such as CeO 2 , ZrO 2 , Pt, Pd, and Rh which are responsible for the catalytic function [16].A used automobile catalytic converter was taken from a Fiat Siena aer running for 140,000 km.Aer puri�cation of the SAC, it was activated in an oven maintained at 120 ∘ C for 12 h and found to contain 0.465% Pd and 0.040% Rh by XRF analysis.

Experimental Procedures
2.1.General. 1 H and 13 C NMR spectra were measured on spectrometer at VARIAN In�nity Plus 300 and at �5 Hz, respectively. 1H and 13 C chemical shis are referenced to the internal deuterated solvent.Solvents were dried following standard methods.All chemicals were purchased from Merck, Alfa Easer, Sigma-Aldrich, and Fluka and the oils were purchased from local supermarket.

�uri�cation of the Catalyst.
A piece of scrap catalyst (50 g) cut by hacksaw was taken from the automobile catalytic converter and washed with chromic acid and distilled water to remove dust and carbonaceous particles.e scrap catalyst was dried in an oven maintained at 120 ∘ C for 12 h, crushed in agate mortar and sieved (<100 m in diameter), and analyzed by XRF.

Optimization of Reaction Conditions.
To optimize the hydrogenation reaction, we examined the reaction conditions in different solvents, such as THF, diethyl ether, hexane, isopropanol, and acetone, for the different reaction times (6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, 48 h, and 72 h) and different amount of catalyst (1 g, 2 g, 3 g, and 4 g).We determined optimization by low iodine value.us, the best results were obtained in THF for 48 h with 4 g catalyst (Table 1).

Hydrogenation Procedures.
A solution of the sun�ower oil (4.0 g) in anhydrous THF (25 mL) was transferred into a two-neck round bottom �ask containing the puri�ed catalyst (4 g).Reactions were carried out by stirring under atmospheric pressure of H 2 at room temperature for 48 h.e reaction mixture was �ltered and the �ltrate was evaporated under vacuum.

Iodine Value.
Iodine values of the partially hydrogenated oils were determined by the known procedures [17].

Results and Discussion
To optimize study of this hydrogenation reaction, the solvent effect of these liquid phase hydrogenation reactions depended on the solubility and chemisorption of H 2 and on the catalyst suspended in the solvent.e solubility and chemisorption of H 2 in a nonpolar solvent are greater than in polar solvents [18].Also, rising reaction times and amount of catalyst increased the amount of hydrogenated oils.Aer 48 hours, rising the hydrogenation was quite sluggish (Table 1).So, the optimum reaction time was considered 48 hours.e 1 H and 13 C NMR spectra of oils have been reported in the literature [19][20][21].e 1 H NMR spectra of sun-�ower oil, which contains linoleic acid (58%), oleic acid (31%), stearic acid, and palmitic acid (11%), show signals between 5.30 and 5.40 ppm relating to ole�nic protons of all acyl chains, at 2.75 ppm for bisallylic protons and at 2.04 ppm for allylic protons of linoleyl chains (Figure 1(a)).On the other hand, the signals of bisallylic protons and allylic protons of linoleyl chains cannot be seen at the 1 H NMR spectra of hydrogenated sun�ower oil (Figure 1(b)) and it shows that the intensity of signals of the ole�nic protons decreased.Although the signals of C9-10 and C12-13 carbons of linoleic acid can be seen between 128.1 and 130.3 ppm at the 13 C NMR spectra of sun�ower oil (Figure 2(a)), they cannot be seen at 13 C NMR spectra of hydrogenated sun�ower oil (Figure 2(b)).Additionally, the 13 C NMR spectra of hydrogenated sun�ower oil showed a chemical shi for the trans-allylic carbons at 32.8 ppm but no chemical shi at 27.3 ppm [22], con�rming that no cisisomers were present in this product.Based on these results, the linoleic acid was hydrogenated to elaidic acid in the sun�ower oil.ese results are consistent with declining iodine value and con�rm the hydrogenation of sun�ower oil.A�er the sun�ower oil was hydrogenated with SAC successfully, the hazelnut oil and tea seed oil were hydrogenated with the same procedures and similar results were observed.e iodine values were given in Table 1.

Conclusions
In conclusion, we have developed a process-friendly, efficient, cheap, and green procedure for the hydrogenation of sun-�ower oil catalyzed by scrap automobile catalyst (SAC) and this hydrogenation procedure was performed on the hazelnut oil and tea seed oil successfully.is method can be used in the fats, oils, and chemical industry.

F 1 :
Comparison of the 300 MHz 1 H-NMR spectra of sun�ower oil (a) and hydrogenated sun�ower oil (b) in CDCl 3 solutions.

F 2 :
Comparison of the 75 MHz 13 C-NMR spectra of sun�ower oil (a) and hydrogenated sun�ower oil (b) in CDCl 3 solutions.
T 1: Catalytic hydrogenation of some vegetable oils using SAC.