Synthesis and characteristics of silica-supported N-heterocyclic carbene catalyst for ring-opening polymerization of D-lactide to produce polylactide

Kim, Eonah; Jang, Jinhee; Chung, Jin Suk

doi:10.1007/s13233-014-2110-1

Cited by 13 publications

(5 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Average pore diameters range between 40 and 60 Å, and particle sizes of 60–23 mesh were reported. Surface areas of 257–550 m 2 /g were found in some cases. ,, Cai and co-workers observed a decrease in surface area from 546 to 419 m 2 /g upon immobilization of NHC–Cu complex 283 . Chung and co-workers, on the other hand, found a slightly increased surface area (257 m 2 /g compared to 278 m 2 /g) of 285 after immobilization .…”

Section: Synthetic Strategies For the Immobilization Of N-heterocycli...mentioning

confidence: 99%

“…Surface areas of 257–550 m 2 /g were found in some cases. ,, Cai and co-workers observed a decrease in surface area from 546 to 419 m 2 /g upon immobilization of NHC–Cu complex 283 . Chung and co-workers, on the other hand, found a slightly increased surface area (257 m 2 /g compared to 278 m 2 /g) of 285 after immobilization . Additionally, in most cases the silica gel was pretreated by heating under vacuum or calcination at high temperatures under inert atmosphere to remove residual water. ,,,, Özdemir et al described the pretreatment of silica gel with methanesulfonic acid to increase the amount of silanol groups on the surface for the preparation of NHC complex 292 .…”

Section: Synthetic Strategies For the Immobilization Of N-heterocycli...mentioning

confidence: 99%

“…Chung and co-workers, on the other hand, found a slightly increased surface area (257 m 2 /g compared to 278 m 2 /g) of 285 after immobilization . Additionally, in most cases the silica gel was pretreated by heating under vacuum or calcination at high temperatures under inert atmosphere to remove residual water. ,,,, Özdemir et al described the pretreatment of silica gel with methanesulfonic acid to increase the amount of silanol groups on the surface for the preparation of NHC complex 292 . Buchmeiser and co-workers reported the end-capping of the residual silanol groups on the silica surface after immobilization of 120 by (CH 3 ) 3 SiOCH 3 and (CH 3 ) 2 Si(OCH 3 ) 2 .…”

Section: Synthetic Strategies For the Immobilization Of N-heterocycli...mentioning

confidence: 99%

See 2 more Smart Citations

Immobilization of N-Heterocyclic Carbene Compounds: A Synthetic Perspective

et al. 2017

View full text Add to dashboard Cite

Over the course of the past 15 years the success story of N-heterocyclic carbene (NHC) compounds in organic, inorganic, and organometallic chemistry has been extended to another dimension. The immobilization of NHC compounds, undergoing continuous diversification, broadens their range of applications and leads to new solutions for challenges in catalytic and synthetic chemistry. This review intends to present a synthetic toolkit for the immobilization of NHC compounds, giving the reader an overview on synthetic techniques and strategies available in the literature. By individually summarizing and assessing the synthetic steps of the immobilization process, a comprehensive picture of the strategies and methodologies for the immobilization of NHC compounds is presented. Furthermore, the characterization of supported NHC compounds is discussed in detail in order to set up necessary criteria for an in-depth analysis of the immobilized derivatives. Finally, the catalytic applications of immobilized NHC compounds are briefly reviewed to illustrate the practical use of this technique for a broad variety of reaction types.

show abstract

Section: Synthetic Strategies For the Immobilization Of N-heterocycli...mentioning

confidence: 99%

Section: Synthetic Strategies For the Immobilization Of N-heterocycli...mentioning

confidence: 99%

Section: Synthetic Strategies For the Immobilization Of N-heterocycli...mentioning

confidence: 99%

See 1 more Smart Citation

Immobilization of N-Heterocyclic Carbene Compounds: A Synthetic Perspective

et al. 2017

View full text Add to dashboard Cite

show abstract

“…A decade ago, Waymouth and Hedrick demonstrated that the N -heterocyclic carbene 1,3-dimesitylimidazol-2-ylidene (IMes) catalyzes lactide polymerization to produce cyclic PLA (Scheme ). − The IMes-catalyzed production of PLA displays complicated kinetics and yields high molecular weight polymer with a polydispersity index (PDI) of less than 1.4, except at high conversions. At conversions greater than 90%, the PDI increases up to about 1.6.…”

Section: Introductionmentioning

confidence: 99%

Stopped-Flow NMR and Quantitative GPC Reveal Unexpected Complexities for the Mechanism of NHC-Catalyzed Lactide Polymerization

Dunn

Landis

2017

Macromolecules

View full text Add to dashboard Cite

Stopped-flow NMR spectroscopy provides the first direct, in situ observation of lactide epimerization during polymerization with the N-heterocyclic carbene organocatalyst 1,3-dimesitylimidazol-2-ylidene (IMes). Hexad analysis of the polymer microstructure using 13C NMR spectroscopy supports a chain-end-controlled mechanism for stereocontrol of the lactide polymerization. Data for both monomer consumption and molecular weight distribution (MWD) as a function of time have been examined using more than one dozen kinetic models. The most successful models feature reversible, unimolecular termination, first-order propagation in monomer, no backbiting term, and include a first-order catalyst death term. The developed modeling method allows insight into a challenging mechanistic problem by successfully modeling MWD evolution and monomer concentration with time.

show abstract

“…The problem of dissolution and loss of classic ionic liquids, for example, based on imidazolium salts, is solved through the use of perfluorinated substituents or through immobilization of the cationic moiety of the molecule onto the matrix surface [26][27][28][29][30]. The choice of the matrix's nature is often governed by two important factors: the presence of reactive centers on its surface capable of efficiently forming covalent "modifier-surface" bonds and structural morphological features of the surface.…”

Section: Introductionmentioning

confidence: 99%

Imidazolium-Modified Silica Gel for Highly Selective Preconcentration of Ag(I) from the Nitric Acid Medium

2022

View full text Add to dashboard Cite

The ion-exchange behavior of an organomineral material with an imidazolium (1-methyl-3-(prop-2-yn-1-yl)-1H-imidazol-3-ium bromide)-modified silica gel was studied for the extraction of Ag(I) from nitric acid media. The extraction from multicomponent systems containing Fe(III), Co(II), Ni(II), Cu(II), Pb(II), and Mn(II) in 100- and 1000-fold molar excesses with respect to Ag(I) was shown to occur with high selectivity. Based on the data of X-ray diffraction and X-ray fluorescence spectroscopy for samples of modified silica gel, a mixed ion exchange–adsorption mechanism for the extraction of Ag(I) was proposed. The effect of the phase contact time and the concentration of nitric acid on the distribution coefficient of Ag(I) was studied. The selectivity factors of the extraction of Ag(I) from multicomponent systems containing foreign cations in 100- and 1000-fold molar excesses under steady-state and dynamic concentration conditions were calculated.

show abstract

Synthesis and characteristics of silica-supported N-heterocyclic carbene catalyst for ring-opening polymerization of D-lactide to produce polylactide

Cited by 13 publications

References 35 publications

Immobilization of N-Heterocyclic Carbene Compounds: A Synthetic Perspective

Immobilization of N-Heterocyclic Carbene Compounds: A Synthetic Perspective

Stopped-Flow NMR and Quantitative GPC Reveal Unexpected Complexities for the Mechanism of NHC-Catalyzed Lactide Polymerization

Imidazolium-Modified Silica Gel for Highly Selective Preconcentration of Ag(I) from the Nitric Acid Medium

Contact Info

Product

Resources

About