the production of thymoquinone from thymol and carvacrol

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7.1.4. FTIR Spectroscopy Analysis IR spectra of NaY zeolite and metal-exchanged zeolites showed strong zeolite lattice bands in the range 450-1200 1/cm as shown in Figure 7.3. The strong and broad band at the region 1000 1/cm could be attributed to the asymmetric stretching vibrations of (Si/Al)O4 units. The broad bands at the region 1650 and 3500 1/cm were due to lattice water molecules and surface hydroxylic groups. No shift of zeolite lattice bands was observed in the spectra of encapsulated complexes given in Figure 7.4, which further implies that the zeolite framework has remained unchanged upon the encapsulation of complexes. Figure 7.3. IR spectra of zeolite NaY, CrNaY, ZnNaY, FeNaY, NiNaY, BiNaY A partial list of the IR spectra results of ligand (Figure 7.5), encapsulated complexes and free complexes (Figure 7.4) were given in Table 7.2. The IR spectra of ligand exhibited a broad band between 2400-2700 1/cm region due to hydrogen bonding between phenolic hydrogen and azomethine nitrogen atoms. The multiple bands around 2900 1/cm in IR spectrum of ligand were due to the presence of -CH2- group. Absence of the band was due to hydrogen bonding and coordination of oxygen to the metal after proton removal. In IR spectra of encapsulated complexes the zeolite bands were dominant. Only weak bands were observed for zeolite-encapsulated complexes due to lower complex concentration. The coordination in the pores could be identified from the 43
ands observed in the region 1200–1600 1/cm where zeolite had no bands. However, the bands due to complexes were weakly intense due to their low concentrations in the lattice as explained by Xavier et al. (2004). Figure 7.4. IR spectra of Cr(salpn)-NaY, Cr (salpn) (a), Bi(salpn)-NaY, Bi(salpn) (b), Fe (salpn)-NaY, Fe(salpn) (c), Ni(salpn)-NaY, Ni(salpn) (d), Zn (salpn)- NaY, Zn (salpn) (f) (cont. on next page) 44
Page 1 and 2:
THE PRODUCTION OF THYMOQUINONE FROM
Page 3 and 4: ACKNOWLEDGEMENTS I would like to ac
Page 5 and 6: ÖZET Bu tezde, genel esnek ligand
Page 7 and 8: 5.4. Catalytic Monoterpene Oxidatio
Page 9 and 10: LIST OF FIGURES Figure Page Figure
Page 11 and 12: LIST OF TABLES Table Page Table 2.1
Page 13 and 14: of thymoquinone are limited only to
Page 15 and 16: advantages compared to homogeneous
Page 17 and 18: NH4 +2 generates the acid sides. Ca
Page 19 and 20: homogeneous internal structures whi
Page 21 and 22: CHAPTER 3 TRANSITION METALS AND COO
Page 23 and 24: 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: Figure 7.2 (cont.) 42
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 and 76: 7.4. Oxidation of Thymol Carvacrol
Page 77 and 78: at 60 o C. Essentail oil contained
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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