Stufenweise Synthese ketten‐ und ringförmiger Siloxane — Kristallstrukturen

Graalmann, O.; Klingebiel, Uwe; Clegg, William; Haase, Martin; Sheldrick, George M.

doi:10.1002/cber.19841170916

Cited by 67 publications

(45 citation statements)

References 8 publications

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“…1.508 (6) C(5)-C(7) 1.538 (5) C(5)--C (8) 1.519 (7) O (2) shorter than in other hydrogen-bonded silanols (Clegg, 1983;Graalmann, Klingebiel, Clegg, Haase & Sheldrick, 1983). This can be ascribed to the electronwithdrawing fluoro substituent, which has also been observed to shorten adjacent Si-N bonds in silazanes (Clegg, Sheldrick & Stalke, 1984).…”

Section: Table 2 Bond Lengths (A) and Angles (°)mentioning

confidence: 88%

Structure of the 1:1 adduct of di-tert-butylfluorosilanol and pyridine N-oxide, C8H19FOSi.C5H5NO

Clegg¹,

Sheldrick²,

Klingebiel³

et al. 1984

Acta Crystallogr C

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Section: Table 2 Bond Lengths (A) and Angles (°)mentioning

confidence: 88%

Structure of the 1:1 adduct of di-tert-butylfluorosilanol and pyridine N-oxide, C8H19FOSi.C5H5NO

Clegg¹,

Sheldrick²,

Klingebiel³

et al. 1984

Acta Crystallogr C

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“…[17] As side products, fluoride-containing compounds are formed, which can be potentially used for the regeneration of the depolymerization reagent. [18] We report herein our investigations on the zinc-catalyzed depolymerization of end-of-life polysiloxanes with benzoyl fluoride as the depolymerization reagent.…”

Section: Methodsmentioning

confidence: 99%

Zinc‐Catalyzed Depolymerization of End‐of‐Life Polysiloxanes

Enthaler

2014

Angewandte Chemie

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Polymers occupy an important role in our current society. Besides their great success, an issue is the accumulation of huge amounts of end-of-life polymers. Currently, the waste management is based primarily on landfills, thermal recycling, and downcycling. Notably, only a small portion of end-of-life materials is recycled by depolymerization, which refers to the creation of synthetic precursors that can be polymerized to new polymers to close the cycle. Widely used polymers in modern times are silicones (polysiloxanes), the intrinsic properties of which make their depolymerization demanding; only a few high-temperature or less environmentally friendly processes have been reported. In this regard, we have established an efficient low-temperature protocol for the depolymerization of silicones with benzoyl fluoride in the presence of cheap zinc salts as precatalysts to yield defined products. Notably, the products can be useful synthetic precursors for the preparation of new polymers, so that an overall recycling process is feasible.Polymers occupy an important and omnipresent role in our current society. Owing to the ready large-scale access and the straightforward adjustability of the properties of polymeric materials, countless applications have been developed in the past, and for the future, an increased demand is expected. [1][2][3][4][5] Besides the great success of polymers, one major issue is the accumulation of huge amounts of end-of-life polymeric materials on a multiton scale every year. At present, the waste-management system is based primarily on landfill storage, thermal recycling (thermal decomposition for energy purposes), and downcycling to produce low-quality materials.[6-9] Significantly, only a small portion of the end-of-life materials is recycled by depolymerization methodologies to create monomers or suitable synthetic precursors that can later be polymerized to high-quality materials to close the cycle. In this way, end-of-life polymers can be a potential feedstock for new polymers. As a consequence, the creation of efficient and resourceful recycling technologies is a challenging task for current society.[10] However, different issues hamper the scope of applications, for example, the high energy demand for depolymerization processes and the existence of mixed polymeric materials originating from different monomers. For the development of such recycling systems, the application of catalysis offers a possibility to perform depolymerization processes, especially for highly stable materials, in an efficient and sustainable manner, to reduce energy costs and to create overall economic advantages. [11] Widely used polymeric materials in modern times are silicones (e.g., silicone oil, silicone rubber, silicone grease, silicone resin), which are accessible by the Müller-Rochow synthesis and subsequent hydrolysis.[12] After the silicones have fulfilled their purpose, one major option is their decomposition to produce, for example, silica. However, the synthesis of silicones requires a hig...

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“…0,02 mol (7) (1) M+; 'H-NMR: b = 1,09 CMe3, 0.52 SiMe; 2 9 Si-NMR: (3 = 7,19 SiCMe3,6,13 SiMe. 28,78 CC3,20,91 CC3,19,01,18,60 CC7,16,79 CC2;2 9 Si-NMR: (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)77 SiCMe3,86 SiCHMe2. < 3 = 27,58 NSiCC,,27,36 OSiCC,,20.00 NSiCC3,19,80 OSiCC3,1,56 SiCH3; 2 9 Si-NMR: (3)(4)(5)(6)(7)(8)(9)(10)54 SiN,06 SiOH,97 SiMe.…”

Section: (1) N O (L)mentioning

confidence: 99%

“…Die Verbindungen 9-11 sind gleich dem bekann ten Trisiloxan-l,5-diol 12 [5] sehr gute Startreagen zien zur Darstellung von Achtringen [2].…”

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Von 1,5-funktionellen Trisiloxanen zu (SiO)₄-, [Si(OSiN)₂Si]- und [O(SiOSi)₂N]-Ringen / From 1,5-Functional Trisiloxanes to (SiO)₄-, [Si(OSiN)₂Si]-, and [O(SiOSi)₂N]-Rings

Schmidt‐Bäse

Klingebiel

1989

Zeitschrift Für Naturforschung B

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Stufenweise Synthese ketten‐ und ringförmiger Siloxane — Kristallstrukturen

Cited by 67 publications

References 8 publications

Structure of the 1:1 adduct of di-tert-butylfluorosilanol and pyridine N-oxide, C8H19FOSi.C5H5NO

Structure of the 1:1 adduct of di-tert-butylfluorosilanol and pyridine N-oxide, C8H19FOSi.C5H5NO

Zinc‐Catalyzed Depolymerization of End‐of‐Life Polysiloxanes

Von 1,5-funktionellen Trisiloxanen zu (SiO)₄-, [Si(OSiN)₂Si]- und [O(SiOSi)₂N]-Ringen / From 1,5-Functional Trisiloxanes to (SiO)₄-, [Si(OSiN)₂Si]-, and [O(SiOSi)₂N]-Rings

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Stufenweise Synthese ketten‐ und ringförmiger Siloxane — Kristallstrukturen

Cited by 67 publications

References 8 publications

Structure of the 1:1 adduct of di-tert-butylfluorosilanol and pyridine N-oxide, C8H19FOSi.C5H5NO

Structure of the 1:1 adduct of di-tert-butylfluorosilanol and pyridine N-oxide, C8H19FOSi.C5H5NO

Zinc‐Catalyzed Depolymerization of End‐of‐Life Polysiloxanes

Von 1,5-funktionellen Trisiloxanen zu (SiO)4-, [Si(OSiN)2Si]- und [O(SiOSi)2N]-Ringen / From 1,5-Functional Trisiloxanes to (SiO)4-, [Si(OSiN)2Si]-, and [O(SiOSi)2N]-Rings

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Von 1,5-funktionellen Trisiloxanen zu (SiO)₄-, [Si(OSiN)₂Si]- und [O(SiOSi)₂N]-Ringen / From 1,5-Functional Trisiloxanes to (SiO)₄-, [Si(OSiN)₂Si]-, and [O(SiOSi)₂N]-Rings