Fries rearrangement over zeolitic catalysts

Fries rearrangement of phenyl acetate over sulfonic modified mesostructured SBA-15 materials

“…The replacement of these conventional catalysts by heterogeneous reusable acid catalysts is promoting an important effort in heterogeneous catalysis research, mainly in the field of zeolites. Zeolites [4][5][6][7][8][9][10] and other acid heterogeneous catalysts such as the sulfonic resin Nafion [9] have been studied as catalytic systems in the Fries rearrangement of phenyl acetate. Rapid deactivation observed in zeolites, either in gaseous or liquid phase, evidence the need for a greater size pore system.…”

Catalytic Reactions over Halide Cluster Complexes of Group 5–7 Metals

“…Consequently, a high-performance catalyst for the Fries rearrangement is expected to have a stabilizing capacity for the cations. Liquid phase reaction exhibited better selectivity for the Fries rearrangement compared with the gas phase reaction [41], in which no solvation for the cations is present. Oxide catalysts generally have both acidic and basic characters.…”

“…Because the carbonyl oxygen strongly coordinates to the Lewis acid center [39], hydrolysis of the Lewis acid is necessary for the isolation of the products. In order to overcome this disadvantage, solid Brønsted acids such as H-Beta zeolite [40][41][42][43], H-Y zeolite [42,44,45], H-ZSM-5 [40][41][42][44][45][46][47], HF/Al 2 O 3 [44], and Nafion-H [48], a resin containing the -CF 2 CF 2 SO 3 H group, are used as the catalyst. However, the selectivity for o-and p-hydroxyacetophenone is not high, and in almost all cases the main product is the decomposition product, phenol.…”

Fries rearrangement of aryl esters catalysed by heteropoly acid: catalyst regeneration and reuse

“…Present practice requires an overstoichiometric amount of a Lewis acid (e.g., AlCl 3 ) or mineral acid (e.g., H 2 SO 4 or HF) as homogeneous catalyst, which results in substantial amount of waste and strong corrosion [1,2]. To overcome this, considerable effort has been put into developing solid acid catalysts for Fries rearrangement, zeolites being the most studied catalysts [1][2][3][4]. As found recently [5,6],…”

“…It provides an important route for the synthesis of aromatic hydroxyketones that are intermediates in manufacturing fine and speciality chemicals as well as pharmaceuticals [1][2][3][4]. The reaction involves acylium ion intermediates that are generated from the ester by interaction with an acid catalyst.…”