Reviews and Accounts ARKIVOC 2012 (i) 570-609
1. Introduction In the past decade, the chemistry of Amberlyst-15 has experienced a rapid development. This growing interest in Amberlyst-15 is mainly due to its mild and highly selective properties, combined with its environmentally benign character and commercial availability. Amberlyst-15 is now routinely used in organic synthesis as other heterogeneous reusable acid catalysts1a-d for various selective transformations of simple and complex molecules. The purpose of the present review is to summarize the utility of Amberlyst-151e-i with emphasis on recent synthetic applications; literature coverage is through the end of 2011.
2. General Information and Structural Features of Amberlyst-15 Amberlyst-15 is brown-grey solid having the following physical properties2a Ionic form as shipped : hydrogen Concentration of active sites: ≥ 1.7 eq/L; ≥ 4.7 eq/kg
Moisture holding capacity : 52 to 57% (H+ form) Shipping weight : 770 g/L Particle size : 0.600 to 0.850 mm Average pore diameter : 300Å Total pore volume : 0.40 mL/g
Maximum operating temperature: 120 ºC (250 ºF) Figure 1 (left) shows an SEM of Amberlyst-15 resin.2b It is a macro reticular polystyrene based ion exchange resin with strongly acidic sulfonic group (Figure 1, right). Thus, it serves as an excellent source of strong acid. It has been used in various acid catalyzed reactions. It is easy to measure, safe to use, and readily removed at the end of the reaction. An additional advantage is that the catalyst can be regenerated and can be used several times.
(CHCH2)n
Figure 1
SO3H Amberlyst-15
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