Polysiloxane. 3. Aminolytische Spaltung von Polysiloxan‐Modellverbindungen

Schimmel, K.-H.

doi:10.1002/actp.1987.010380809

Cited by 27 publications

(14 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many depolymerization reagents have been reported, such as alcohol [1][2][3], hydrogen chloride [4,5], thionyl chloride [6][7][8][9] and amines [10][11][12][13][14][15]. Alcohol is the most common reagent.…”

Section: Introductionmentioning

confidence: 99%

Polysiloxane depolymerization with dimethyl carbonate using alkali metal halide catalysts

Okamoto

Suzuki

2004

Applied Catalysis A: General

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Polysiloxane depolymerization with dimethyl carbonate using alkali metal halide catalysts

Okamoto

Suzuki

2004

Applied Catalysis A: General

View full text Add to dashboard Cite

“…Interestingly, the iron(II,III) oxide was recycled five times showing still activity after run 4 ( Table 1, entry 16). Moreover, the amount of the depolymerization reagent 2 was increased to 3 or 4 equivalents with respect to the polymer subunit revealing an increase of the yield ( Table 1, entries [17][18][19]. Furthermore, a decrease of the reaction temperature to 140°C showed a decrease of the catalyst activity (Table 1, entries 21-23).…”

Section: Resultsmentioning

confidence: 99%

“…In an associated process the chemicals can be polymerized to new high-quality materials. However, so far only a few number of high temperature (>200°C) or less efficient protocols have been reported [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. More recently we described zinc-and iron-catalyzed depolymerizations (<150°C) of poly(dimethylsiloxane)s with acid fluorides as depolymerization reagents producing as low-molecular chemicals difluorodimethylsilane and 1,3-difluoro-1,1,3,3tetramethyldisiloxane, under non-inert and solvent-free conditions, which were easily polymerized to access new polysiloxanes, and overall establish a recycling process ( Fig.…”

mentioning

confidence: 99%

Iron‐catalyzed depolymerizations of silicones with hexanoic anhydride provide a potential recycling method for end‐of‐life polymers

Weidauer¹,

Heyder²,

Woelki³

et al. 2015

Euro J Lipid Sci & Tech

View full text Add to dashboard Cite

One of the great impacts of polymeric materials is the matter of the accumulation of huge amounts of end-oflife polymers. At the present date, waste management is based primarily on landfills, thermal recycling, and down-cycling, while only a small part of the waste is subjected to feedstock recycling. In more detail, polymers are converted to low-molecular weight synthons by depolymerization and a subsequent polymerization process creates new high-quality polymers. Widely-used polymers in modern society are polysiloxanes (silicones) and recycling is still an issue. In this regard, we present herein the depolymerization of polysiloxanes, applying a fatty acid anhydride as the depolymerization reagent. In the presence of catalytic amounts of iron salts, low-molecular weight products with the motif RC(R with water revealed the formation of octamethylcyclotetra-and decamethylcyclopentasiloxanes and the corresponding fatty acid as side product, which can potentially be reconverted to the fatty acid anhydride. Interestingly, a recycling of the polymer and the depolymerization reagent is feasible.Practical applications: Huge amounts of end-of-life polymers are produced by our society and several methodologies for waste treatment have been established so far. One interesting recycling approach can be the conversion of end-of-life polymers, via depolymerization, into useful commodities, which can be applied as feedstock for new materials. Taking these aspects into account we studied the depolymerization of end-of-life polysiloxanes, applying cheap and abundant iron salts as a precatalyst and a fatty acid anhydride as a depolymerization reagent, which can be easily accessed from renewable resources, hence avoiding the use of fossil fuels-based chemicals. As major products RC( --O) (OSiMe 2 ) m OC( --O)R were obtained, these can be utilized as starting material for new polysiloxanes. Moreover, the simple operation of the reaction (e.g., no protection atmosphere, solvent free) makes this recycling method attractive for large scale applications.

show abstract

“…In this regard, low‐temperature depolymerization methodologies can be an option to overcome these limitations, since a smaller amount of energy should be necessary to allow a recycling. Unfortunately, the intrinsic properties of silicones constrain the application of depolymerization processes, hence only a few high temperature (>200°C) or less environmental‐friendly processes have been reported . Recently, we studied the depolymerization of end‐of‐life polysiloxanes to produce suitable chemicals (e.g., Me 2 SiF 2 ) as prospective starting materials for polymerization.…”

Section: Introductionmentioning

confidence: 99%

Iron‐catalyzed depolymerization of polysiloxanes to produce dichlorodimethylsilane, diacetoxydimethylsilane, or dimethoxydimethylsilane

Enthaler

2014

J of Applied Polymer Sci

View full text Add to dashboard Cite

Polymers are one of the important pillars of our current society. Besides the great success a matter is the accumulation of huge amounts of end-of-life polymers. Current waste management bases primarily on landfills, thermal recycling, and down-cycling. Noteworthy, only a small part of the end-of-life materials is recycled by depolymerization, means low-molecular weight synthons are created, which can be polymerized to new polymers to close the cycle. Widely used polymers in modern life times are silicones (polysiloxanes). Based on the intrinsic properties the depolymerization is challenging and only a few high temperature or less environmental-friendly processes have been reported. In this regard, we have set up a capable low-temperature protocol for the depolymerization of silicones with acid chlorides, acetic acid, or methanol in the presence of cheap iron salts as precatalysts to yield dichlorodimethylsilane, diacetoxydimethylsilane, or dimethoxydimethylsilane as well-defined products. Notably, dichlorodimethylsilane, diacetoxydimethylsilane, and dimethoxydimethylsilane can be useful starting materials for synthesizing new polymers; overall a recycling is feasible.

show abstract

Polysiloxane. 3. Aminolytische Spaltung von Polysiloxan‐Modellverbindungen

Cited by 27 publications

References 3 publications

Polysiloxane depolymerization with dimethyl carbonate using alkali metal halide catalysts

Polysiloxane depolymerization with dimethyl carbonate using alkali metal halide catalysts

Iron‐catalyzed depolymerizations of silicones with hexanoic anhydride provide a potential recycling method for end‐of‐life polymers

Iron‐catalyzed depolymerization of polysiloxanes to produce dichlorodimethylsilane, diacetoxydimethylsilane, or dimethoxydimethylsilane

Contact Info

Product

Resources

About