the production of thymoquinone from thymol and carvacrol

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conversion (wt.%) 45 40 35 30 25 20 15 10 5 0 0 100 200 300 400 500 time (min.) thymol oxidation carvacrol oxidation Figure 7.15. The percentage of thymol and carvacrol conversion (reaction conditions: thymol or carvacrol/H2O2 molar ratio=1, 0.2 g Cr (salpn)-NaY catalyst, 60ºC) 7.5. Oxidation of Thyme Essential Oil There were several reports in the literature about the chemical composition of essential oil. The summary of these studies were also given in Chapter 5. Most reports indicated that thymol or carvacrol were the major component in the essential oil (Dorman et al. 1995). In this study, essential oil which was purchased from Arifo ulları Company was analyzed in HPLC. Essentail oil contains many monoterpenes. However, in HPLC analyses only carvacrol and thymoquinone were observed and no other components were identified such as thymol, p-cymene, α -terpinene for three different wavelengths (254 nm, 280 nm, 295 nm). In the literature for oxidation reactions, large differences have been observed between GC and HPLC analysis results. Using GC for the analysis of reaction mixtures in the presence of residual H2O2, products were oxidized by H2O2 at elevated temperature in the GC system (Ma et al. 2002). Hence, lately HPLC was preferred technique for the oxidation reactions. As shown in Figure 7.16 carvacrol was the major component and it was converted to BQ, THQ, TQ (with 33.6% yield), unknown products with 70% conversion 65
at 60 o C. Essentail oil contained thymoquinone. After the oxidation reaction thymoquinone amount was increased. Figure 7.16. HPLC chromatograms of thyme essential oil before and after oxidation reaction (reaction conditions: 0.2 g Cr (salpn)-NaY catalyst, 60 ºC) 66
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THE PRODUCTION OF THYMOQUINONE FROM
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ACKNOWLEDGEMENTS I would like to ac
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ÖZET Bu tezde, genel esnek ligand
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5.4. Catalytic Monoterpene Oxidatio
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LIST OF FIGURES Figure Page Figure
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LIST OF TABLES Table Page Table 2.1
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of thymoquinone are limited only to
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advantages compared to homogeneous
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NH4 +2 generates the acid sides. Ca
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homogeneous internal structures whi
Page 21 and 22:
CHAPTER 3 TRANSITION METALS AND COO
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not determined by orbital energy al
Page 25 and 26: 3.3.1. Oxidation State The transiti
Page 27 and 28: it surrounds the metal, forms very
Page 29 and 30: metal complexes catalyze the reacti
Page 31 and 32: Figure 4.1. Flexible ligand method:
Page 33 and 34: included in the synthesis mixture.
Page 35 and 36: CHAPTER 5 OXIDATION OF MONOTERPENES
Page 37 and 38: In the GC-MS analysis of the oil of
Page 39 and 40: There are few studies on monoterpen
Page 41 and 42: Homolytic Pathways: Heterolytic Pat
Page 43 and 44: 6.1. Materials CHAPTER 6 EXPERIMENT
Page 45 and 46: inductively coupled plasma spectrom
Page 47 and 48: These tests were performed in detai
Page 49 and 50: Table 7.1. Metal content of encapsu
Page 51 and 52: 7.1.3. X-ray Diffraction (XRD) Anal
Page 53 and 54: Figure 7.2 (cont.) 42
Page 55 and 56: ands observed in the region 1200-16
Page 57 and 58: Figure 7.5. IR spectra ligand (H2 s
Page 59 and 60: Figure 7.6. DSC analysis result sho
Page 61 and 62: 7.2. Catalytic Activities 7.2.1. De
Page 63 and 64: eaction products, among which TQ wa
Page 65 and 66: carvacrol conversion (%) 16 14 12 1
Page 67 and 68: e 11.6% with a small amount of THQ.
Page 69 and 70: during the oxidation process and th
Page 71 and 72: leaching of Cr (salpn) complexes fr
Page 73 and 74: 7.3.2. Effect of Temperature Four d
Page 75: 7.4. Oxidation of Thymol Carvacrol
Page 79 and 80: REFERENCES Anthony, F., 1999. Advan
Page 81 and 82: Martin, R.R.L., Neves, G. 2001. “
Page 83 and 84: APPENDIX A DETERMINATION OF HYDROGE
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