Alumina sulfuric acid (ASA), tungstate sulfuric acid (TSA), molybdate sulfuric acid (MSA) and xanthan sulfuric acid (XSA) as solid and heterogeneous catalysts in green organic synthesis: a review

Nanostructured silicate catalysts for environmentally benign Strecker-type reactions:status quoandquo vadis

“…However, pure SiO 2 is not active in the S-3-CR, as indicated by Iwanami et al, 32 while silica sulfuric acid (SSA, SiO 2 -SO 3 H) is very effective, as demonstrated by Chen and Lu. 46 This reusable green and inexpensive heterogeneous acid catalyst has been widely investigated [47][48][49][50][51] since 2001, when Zol-gol described its preparation by using a simple reaction of neat chlorosulfonic acid and silica gel (Fig. 2A).…”

Sulfonated alumina: A suitable catalyst for furfural biomass building-block valorization through multicomponent reactions

“…H. Patel and col./et al reviewed the utilization of several novel heterogeneous catalysts and their use in organic synthesis, for example, alumina sulfuric acid (ASA), tungstate sulfuric acid (TSA), molybdate sulfuric acid (MSA), and xanthan sulfuric acid (XSA) [2]. These materials are economical, efficient, and compatible with the environment.…”

“…These materials are economical, efficient, and compatible with the environment. Particularly, they described the use of alumina sulfuric acid, obtained by the reaction between chlorosulfonic acid and activated neutral alumina in the synthesis of several organic compounds such as benzimidazoles, quinoxalines, nitration of aromatic compounds, synthesis of 2,5-disubstituted 1,3,4oxadiazoles, dithioacetalization, ortho-silylation of alcohols, oximes and phenols, Biginelli-type condensation reaction, and Pechmann condensation [2].…”