Modified ZSM-5 Catalysts for the Synthesis of Five- and Six-Membered Heterocyclic Compounds

Synthesis of N-heterocyclic compounds over zeolite molecular sieve catalysts: an approach towards green chemistry

“…Vapour phase synthesis of N-methyl pyrrolidine and tetrahydrofuran via intermolecular cyclization of diol and alkylamine over modified ZSM-5 catalysts was reported by Subba Rao et al 69 (Scheme 8). The reaction has been studied with 1,4-butanediol and methylamine over different modified ZSM-5 catalysts.…”

Green Organic Synthesis of N-Methylpyrrolidine

“…The less than 50 % yield product of N-methylpyrrolidine is then isolated by extraction with an aliphatic hydrocarbon solvent. Subba Rao et al [3] also reported that the N-methylpyrrolidine could be synthesized via the cyclization reaction of 1,4-butanediol and methylamine as using the modified ZSM-5 catalysts. The results revealed that the yield product of N-methylpyrrolidine was only 10 % when the operating temperature was less than 300 o C. Also, the yield product was impossibly enhanced as increasing the temperature, because the side product of this synthesis process such as aromatics was remarkably facilitated when the temperature was over 300 o C. According to the Hofmann-Löffler-Freytag reaction [4], the N-pyrrolidine derivatives are also synthesized from the N-alkyl-N-chloroamine, where the acid is used as regards the solvent of this synthesis process.…”

Theoretical investigations of 1,4‐butanediol and 2‐butene‐1,4‐diol cyclodehydration using postprocessing visualization of quantum chemical calculation data

“…Several possible reaction mechanisms for cyclodehydration of 1,4‐butanediols were discussed in the literature 4, 9–11. The suggestion was made that tetrahydrofuran is formed by the sequence of adsorption of 1,4‐butanediol onto Brensted acid centers, protonation by one of the hydroxyl groups, removal of a water molecule with the formation of a carbocation, and cyclization.…”