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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Figure 7.6. DSC analysis result showed good agreement with previously reported<br />
melting point value <strong>of</strong> 52 ºC (Maurya et al. 2002a).<br />
Figure 7.6. DSC analysis <strong>of</strong> H2 (salpn) (L) lig<strong>and</strong><br />
7.1.6.2. Thermal Gravimetric Analyses (TGA)<br />
TGA curves <strong>of</strong> <strong>the</strong> NaY zeolite, Cr exchanged NaY zeolite, Cr (salpn)-NaY<br />
catalysts were shown in Figure 7.7. Total amount <strong>of</strong> water lost below 800 o C in each<br />
sample was represented in Table 7.4.<br />
Table 7.4. Total amount <strong>of</strong> weight loss up to 800 o C for NaY, CrNaY, Cr(salpn)-NaY<br />
Sample % Weight loss up to 800 o C<br />
NaY 23.7<br />
CrNaY 24.1<br />
Cr (Salpn)-NaY 25.5<br />
TGA analysis <strong>of</strong> NaY, Cr exchanged NaY zeolite shows that <strong>the</strong>re was a total<br />
mass decrease <strong>of</strong> 23.7%, 24.1%, which can be attributed to dehydration (Chavan et al.<br />
2000). Cr (salpn)-NaY presented a total mass decrease <strong>of</strong> 25.5%, due to <strong>the</strong> loss <strong>of</strong><br />
water <strong>and</strong> organic material. The water loss values between 23.7% <strong>and</strong> 24.1% for NaY<br />
zeolite <strong>and</strong> CrNaY indicated <strong>the</strong> dependence <strong>of</strong> water content <strong>of</strong> zeolite Y on <strong>the</strong> cation<br />
type. When Cr ion was exchanged with Na ion, <strong>the</strong> water containing <strong>of</strong> zeolite was<br />
changed.<br />
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