Combination of Sulfite Anion and Phase Transfer Catalysts for Green Cyclotrimerization of Aryl Isocyanates

Dekamin, Mohammad G.; Mallakpour, Shadpour; Ghassemi, Maryam

doi:10.1081/scc-200048951

Cited by 9 publications

(3 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, isocyanurates have been prepared by cyclotrimerization reaction from isocyanates and these types of heterocyclic and aromatic compounds have been used in a variety of materials. 53,54 Due to their excellent thermal and chemical properties, isocyanurates have been used to improve polymers, such as increasing the electrical properties and thermal stability of copolyimides, 55 syntheses of highly stable plastic 56 and amphiphilic polyethylene glycol gels, 57 and increasing the flame retardancy and thermal stability of epoxy resins 58,59 and polypropylene. 60,61 Isocyanurates are also an important class of compounds for improving coating and other properties of polyurethane.…”

Section: Introductionmentioning

confidence: 99%

The catalytic effects of in situ prepared N-heterocyclic carbenes from benzimidazole salts in Suzuki–Miyaura cross-coupling reaction and uses in catalytic preparation of 1,3,5-triphenyl-1,3,5-triazinane-2,4,6-trione from phenyl isocyanate

Yılmaz¹,

Küçükbay²

2018

Turk J Chem

View full text Add to dashboard Cite

Many benzimidazole salts bearing a 3-phenylpropyl substituent (1a-1h) were synthesized and their structures were identified by 1 H NMR, 13 C NMR, and IR spectroscopic methods and elemental analysis. These N-heterocyclic carbene (NHC) precursors were used as a part of a catalytic system including Pd(OAc) 2 and the base in the Suzuki-Miyaura cross-coupling reaction under microwave irradiation. They were also used as catalysts in the cyclotrimerization of phenyl isocyanate to yield 1,3,5-triphenyl-1,3,5-triazinane-2,4,6-trione. It has been observed that benzimidazole salts made a positive contribution to both catalytic reactions as a NHC precursor.

show abstract

Section: Introductionmentioning

confidence: 99%

The catalytic effects of in situ prepared N-heterocyclic carbenes from benzimidazole salts in Suzuki–Miyaura cross-coupling reaction and uses in catalytic preparation of 1,3,5-triphenyl-1,3,5-triazinane-2,4,6-trione from phenyl isocyanate

Yılmaz¹,

Küçükbay²

2018

Turk J Chem

View full text Add to dashboard Cite

show abstract

“…It was found that potassium sulfite (K 2 SO 3 , 34) shows catalytic activity only in the presence of a PTC, which improves the solubility and nucleophilicity of K 2 SO 3 in the organic phase. [59] With an optimal catalyst loading of 0.33 mol % K 2 SO 3 and 0.33 mol % tetrabutylammonium bromide, the cyclotrimerization of various aryl isocyanates was carried out at 70 °C in bulk and yields of 80-90 % were obtained. Using K 2 SO 3 as a catalyst, the catalytic activity was optimized by selection of ammonium salts of Br À , I À , BF 4 À , or ClO 4 À as PTC.…”

Section: Lewis Basic Catalystsmentioning

confidence: 99%

“…The co‐catalytic effect of PTCs was studied further. It was found that potassium sulfite (K 2 SO 3 , 34 ) shows catalytic activity only in the presence of a PTC, which improves the solubility and nucleophilicity of K 2 SO 3 in the organic phase [59] . With an optimal catalyst loading of 0.33 mol % K 2 SO 3 and 0.33 mol % tetrabutylammonium bromide, the cyclotrimerization of various aryl isocyanates was carried out at 70 °C in bulk and yields of 80–90 % were obtained.…”

Section: Catalysts Operating Via Lewis Basic Cyclotrimerization Mecha...mentioning

confidence: 99%

Catalysts for Isocyanate Cyclotrimerization

et al. 2023

View full text Add to dashboard Cite

The formation of isocyanurate via cyclotrimerization of isocyanates is widely reported to provide a variety of polyurethane materials with improved chemical and physical properties such as weatherability, mechanical properties, thermal stability and flame retardancy. The demand for development of effective and selective catalysts for cyclotrimerization of isocyanates has been increasing. This review comprehensively summarizes catalysts for the cyclotrimerization of isocyanates that have been reported in peer‐reviewed publications and provides a valuable guideline for choosing suitable catalysts to match specific requirements. The catalysts are categorized into two main classes: catalysts operating via a Lewis basic cyclotrimerization mechanism and metal‐containing catalysts. Catalyst structures, reaction conditions, reaction time, catalytic effectivity as well as types of isocyanates whose trimerization is catalyzed are described in detail. In addition, featuring the findings and viewpoints from mechanistic studies, this review aims to stimulate the design and development of new, more efficient catalysts, and to guide further study of the trimerization mechanism with different classes of catalysts.

show abstract