chapter 2 palladium catalysts in suzuki cross- coupling reaction
chapter 2 palladium catalysts in suzuki cross- coupling reaction
chapter 2 palladium catalysts in suzuki cross- coupling reaction
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
CHAPTER 4<br />
EXPERIMENTAL STUDY<br />
4.1. Palladium-Loaded Zeolite Catalyst Preparation<br />
Pd(NH3)4Cl2 complex was synthesized from PdCl2 (Fluka, 47% purum) and a<br />
commercial ammonia solution (Merck, 25%). NH3 solution was added over PdCl2<br />
complex and some water was added drop wise to this solution while stirr<strong>in</strong>g until the<br />
solution color turned to yellow from tobacco color. This solution was boiled to remove<br />
water and yellow crystals were obta<strong>in</strong>ed. Then this complex was recrystalized with<br />
extra pure ethanol (Riedel, 95%).<br />
Pd(NH3)4 2+ was <strong>in</strong>troduced <strong>in</strong>to the NaY zeolite (Zeolyst International,<br />
CBV100, SiO2/Al2O3 mol ratio: 5.1) by ion exchange with 200 mL 0.1 M NH4OH<br />
solution of Pd(NH3)4Cl2 for two grams of zeolite <strong>in</strong> as-received form, correspond<strong>in</strong>g,<br />
approximately, to 0.8 or 0.2 wt% of Pd on the zeolite. The Pd solution and zeolite<br />
mixture was stirred at room temperature for 2 h, filtered and washed with water until no<br />
chloride ion was detectible with<strong>in</strong> the filtrate. The solid was left under ambient<br />
conditions to elim<strong>in</strong>ate its excess water content. The application of higher temperatures<br />
and high vacuums resulted <strong>in</strong> less active catalyst.<br />
NaY<br />
PdCl 2 + NH 4OH<br />
[Pd(NH 3) 4]Cl 2<br />
-NaCl<br />
[Pd(NH 3) 4] +2 -Y<br />
Figure 4.1. Preparation of [Pd(NH3)4] +2 -Y catalyst from NaY zeolite<br />
43