Redox Initiated Cationic Polymerization: Reduction of Triarylsulfonium Salts by Silanes

Crivello, James V.

doi:10.1007/s12633-009-9007-1

Cited by 21 publications

(23 citation statements)

References 38 publications

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“…Indeed, it is more difficult to reduce triarylsulfonium salts (E red = −28 kcal/mol) [188] than diaryliodonium salts (E red = −5 kcal/mol) [187]. One was successful using noble metal catalysts and vapor state silane for the polymerization of highly reactive activated epoxides and vinyl ethers [189]. These monomers show a better reactivity compared to classical epoxide ones (see below).…”

Section: Other Catalystsmentioning

confidence: 99%

Redox two-component initiated free radical and cationic polymerizations: Concepts, reactions and applications

Garra

Dietlin

Morlet‐Savary

et al. 2019

Progress in Polymer Science

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Redox polymerizations are of huge importance throughout academic and industrial polymer science. Many authors propose the reaction of reducing (Red) and oxidizing (Ox) agents to accelerate/initiate radical or cationic polymerizations. As a result of activation energies typically below 80 kJ/mol, such reactions can occur under mild conditions, e.g., at room temperature, with reduced energy consumptions and robust in applications, such as the fabrication of composites. However, a clear definition of redox polymerization can only be found in reviews dealing with redox free radical polymerizations (FRP) published twenty years ago (or more). Therefore, a fresh and broader update is provided here for more recent work. The concepts involved when the "Red" and "Ox" agents constituting the redox initiating system are mixed under mild conditions are presented, followed by a discussion of the redox FRP initiating systems in bulk. Initiating systems dealing with the redox cationic polymerization (CP) are reviewed, and parallels between conventional FRP/CP and controlled polymerizations, in which redox systems are used, is provided. Many redox agents are useful in both modes. Finally, dual-cure (redox/photochemical; redox dual FRP/CP) systems is presented and selected applications are reviewed. Altogether, the state of the art for redox two-component polymerizations is provided, along with some perspectives.

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Section: Other Catalystsmentioning

confidence: 99%

Redox two-component initiated free radical and cationic polymerizations: Concepts, reactions and applications

Garra

Dietlin

Morlet‐Savary

et al. 2019

Progress in Polymer Science

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“…In our previous work on redox initiated cationic polymerization, 4,5 we showed that silanes are powerful reducing agents for both diaryliodonium and triarylsulfonium salts whereas 9-borabicyclo[3.3.1]nonane (9-BBN) 7 was more selective, capable of reducing only the more easily reduced diaryliodonium salts. In view of the stability of N-aryl heteroaromatic onium salts, it appeared reasonable to attempt their reduction with the more powerful silane reducing agents.…”

Section: Study Of the Reduction Of N-aryl Heteroaromatic Onium Saltsmentioning

confidence: 99%

“…In a series of recent papers from this laboratory, [4][5][6][7] we have reported the development of a two new types of initiator systems for carrying out cationic polymerization reactions. These initiator systems are based on redox couples in which diaryliodonium and triarylsulfonium salts were used as the oxidants while a dialkylborane or various silanes bearing the SiAH group were used as the reducing agents.…”

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confidence: 99%

Redox initiated cationic polymerization: Silane‐N‐aryl heteroaromatic onium salt redox couples

Crivello

Lee

2010

J. Polym. Sci. A Polym. Chem.

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In this article, a new route for the synthesis of N‐aryl heteroaromatic onium salts by the direct copper catalyzed arylation of pyridine, substituted pyridines, isoquinoline, and acridine with diaryliodonium salts is described. It was demonstrated that these N‐aryl heteroaromatic onium salts undergo facile platinum or rhodium‐catalyzed reduction by silanes bearing SiH groups. The reduction of N‐aryl heteroaromatic onium salts generates Brønsted acids. When this redox reaction was carried out in situ in the presence of an appropriate monomer, cationic polymerization was observed. Using this approach, the cationic polymerizations of epoxides, oxetanes, 1,3,5‐trioxane, styrene, and vinyl ethers were carried out. The use of optical pyrometry to monitor the redox initiated cationic polymerizations of some representative multifunctional monomers is described. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

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“…After an equilibration period of 20 s, a predetermined amount of the silane was added to the pan using a syringe while the monomer-catalyst-onium salt solution was rapidly stirred. All polymerizations were carried out at an initial temperature of [23][24][25] • C. During kinetic runs, the temperature of the sample was monitored at a rate of one measurement per second.…”

Section: Optical Pyrometrymentioning

confidence: 99%

Silane reduction of onium salts

Crivello

2009

Applied Organom Chemis

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Novel redox initiators for cationic polymerizations were developed consisting of an onium salt together with a Si-H functional silane or siloxane. The reduction of the onium salt by the silane is catalyzed by noble metal complexes or certain transition metal compounds and takes place spontaneously at room temperature. The redox reaction of the onium salt with the silane results in the liberation of a strong Brønsted acid that can be subsequently used to initiate cationic polymerizations. Typical onium salts that have been employed in these redox initiator systems are diaryliodonium salts, triarylsulfonium salts and S,S-dialkyl-Sphenacylsulfonium salts. Studies of the effects of variations in the structures of the onium salt, the silane and the type of noble metal catalyst were carried out. In principle, the redox initiator systems are applicable to all types of cationically polymerizable monomers and oligomers, including the ring-opening polymerizations of such heterocyclic monomers as epoxides and oxetanes and, in addition, the polymerization of vinyl monomers such as vinyl ethers, N-vinylcarbazole and styrenic monomers. The use of these novel initiator systems for carrying out commercially attractive crosslinking polymerizations for coatings, composites and encapsulations is discussed.

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Redox Initiated Cationic Polymerization: Reduction of Triarylsulfonium Salts by Silanes

Cited by 21 publications

References 38 publications

Redox two-component initiated free radical and cationic polymerizations: Concepts, reactions and applications

Redox two-component initiated free radical and cationic polymerizations: Concepts, reactions and applications

Redox initiated cationic polymerization: Silane‐N‐aryl heteroaromatic onium salt redox couples

Silane reduction of onium salts

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