the production of thymoquinone from thymol and carvacrol
the production of thymoquinone from thymol and carvacrol
the production of thymoquinone from thymol and carvacrol
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washed with 10 ml cold methanol <strong>and</strong> dried. Finally, <strong>the</strong> lig<strong>and</strong> was recrystallized <strong>from</strong><br />
methanol to give pure product. The melting point <strong>of</strong> lig<strong>and</strong> was found by differential<br />
scanning calorimetric analysis (DSC). DSC analysis was conducted using Shimadzu<br />
DSC50 types <strong>of</strong> instrument. Run was carried out up to 600 o C at 10 ºC/min heating rate<br />
<strong>and</strong> nitrogen flow rate with 3 mg <strong>of</strong> sample.<br />
6.2.1.2. Preparation <strong>of</strong> Metal Exchanged Zeolite Y<br />
NaY-zeolite (5 g) was suspended in 300 ml deionized water containing 0.01 M<br />
<strong>of</strong> metal (Cr(III), Fe(III), Bi(III), Ni(II), Zn(II)) nitrates. The mixture was heated to 60<br />
ºC while stirring for 24 hours. The solid was filtrated, washed with hot distilled water<br />
till <strong>the</strong> filtrate was free <strong>from</strong> any metal ion content <strong>and</strong> <strong>the</strong>n dried for 24 hours at 90 ºC<br />
in air.<br />
6.2.1.3. Preparation <strong>of</strong> Encapsulated Complexes<br />
The encapsulated metal complex was prepared by general flexible lig<strong>and</strong><br />
method. A total <strong>of</strong> 5g metal exchanged Y zeolite <strong>and</strong> 10 g <strong>of</strong> lig<strong>and</strong> were mixed in<br />
round bottom flask. The mixture was heated at 100 ºC overnight (19 hours) in an oil<br />
bath with stirring. The lig<strong>and</strong> was melted at that temperature <strong>and</strong> acted as a solvent as<br />
well as a reactant. The resulting material was taken out <strong>and</strong> soxhlet extracted with<br />
methanol till <strong>the</strong> complex was free <strong>from</strong> unreacted excess lig<strong>and</strong> (at least 62 hours). The<br />
uncomplexed metal ions present in <strong>the</strong> zeolite were removed by exchanging <strong>the</strong>m with<br />
0.01 M aqueous NaCl solution for 5 hours. The resulting solid <strong>the</strong>n was washed with<br />
hot distilled water till no precipitation <strong>of</strong> AgCl on reacting filtrate with AgNO3 was<br />
observed. The colored solid was dried at 90 ºC for 24 hours.<br />
6.2.2. Catalyst Characterization<br />
X-ray diffraction (XRD) patterns <strong>of</strong> <strong>the</strong> samples were recorded on a Philips<br />
X'pert Pro X-ray diffractometer with Cu K radiation. Infrared spectra in <strong>the</strong> region<br />
400-4000 cm -1 were recorded in KBr pellets using a Shimadzu 8101 FT-IR<br />
spectrophotometer. The metal contents in <strong>the</strong> products were determined by an<br />
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