Assessment of Catalyst Selectivity in Carbon-Nanotube Silylesterification

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Abstract

The functionalization of carbon nanotubes (CNTs) plays a key role in their solubilization and compatibility for many applications. Among the many possible ways to functionalize CNTs, the creation of an Si–O–C bond is crucial for the formation of silicone composites. Catalyst-mediated silylesterification is useful in creating Si–O–C bonds because it is cost-effective and uses a hydrosilane precursor of lower reactivity than that of chlorosilane. However, it was previously demonstrated that two important silylesterification catalysts (zinc chloride and Karstedt’s catalyst) exhibit different selectivity for oxidized functional groups that are present on the surface of CNTs after oxidative acid treatment. This report details the selective modification of CNTs with various oxygenated functional groups (aromatic and nonaromatic alcohols, carboxylic acids, ethers, and ketones) using diazonium chemistry. Modified CNTs were used to assess the specifity of zinc chloride and Karstedt’s catalyst for oxygenated functional groups during a silylesterification reaction. Karstedt’s catalyst appeared to be widely applicable, allowing for the silylesterification of all of the aforementioned oxygenated functional groups. However, it showed lower efficacy for ethers and ketones. By contrast, zinc chloride was found to be very specific for nonaromatic carboxylic acids. This study also examined the Hansen solubility parameters of modified CNTs.
Original languageEnglish
JournalApplied Sciences
Volume10
DOIs
Publication statusPublished - 2020

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Carbon Nanotubes
Catalyst selectivity
Carbon nanotubes
selectivity
carbon nanotubes
zinc chlorides
Zinc chloride
catalysts
Functional groups
Catalysts
Ethers
Carboxylic Acids
Ketones
Carboxylic acids
carboxylic acids
ketones
ethers
chlorosilanes
silicones
Silicones

Keywords

  • carbon nanotubes; aryl diazonium salts; silylesterification; hydrosilanes; zinc chloride; Karstedt’s catalyst; Hansen solubility parameters.

Cite this

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title = "Assessment of Catalyst Selectivity in Carbon-Nanotube Silylesterification",
abstract = "The functionalization of carbon nanotubes (CNTs) plays a key role in their solubilization and compatibility for many applications. Among the many possible ways to functionalize CNTs, the creation of an Si–O–C bond is crucial for the formation of silicone composites. Catalyst-mediated silylesterification is useful in creating Si–O–C bonds because it is cost-effective and uses a hydrosilane precursor of lower reactivity than that of chlorosilane. However, it was previously demonstrated that two important silylesterification catalysts (zinc chloride and Karstedt’s catalyst) exhibit different selectivity for oxidized functional groups that are present on the surface of CNTs after oxidative acid treatment. This report details the selective modification of CNTs with various oxygenated functional groups (aromatic and nonaromatic alcohols, carboxylic acids, ethers, and ketones) using diazonium chemistry. Modified CNTs were used to assess the specifity of zinc chloride and Karstedt’s catalyst for oxygenated functional groups during a silylesterification reaction. Karstedt’s catalyst appeared to be widely applicable, allowing for the silylesterification of all of the aforementioned oxygenated functional groups. However, it showed lower efficacy for ethers and ketones. By contrast, zinc chloride was found to be very specific for nonaromatic carboxylic acids. This study also examined the Hansen solubility parameters of modified CNTs.",
keywords = "carbon nanotubes; aryl diazonium salts; silylesterification; hydrosilanes; zinc chloride; Karstedt’s catalyst; Hansen solubility parameters.",
author = "Simon Detriche and Bhakta, {Arvind Kumar} and Patrick N’Twali and Joseph Delhalle and Zineb Mekhalif",
year = "2020",
doi = "10.3390/app10010109",
language = "English",
volume = "10",
journal = "Applied Sciences",
issn = "2076-3417",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",

}

TY - JOUR

T1 - Assessment of Catalyst Selectivity in Carbon-Nanotube Silylesterification

AU - Detriche, Simon

AU - Bhakta, Arvind Kumar

AU - N’Twali, Patrick

AU - Delhalle, Joseph

AU - Mekhalif, Zineb

PY - 2020

Y1 - 2020

N2 - The functionalization of carbon nanotubes (CNTs) plays a key role in their solubilization and compatibility for many applications. Among the many possible ways to functionalize CNTs, the creation of an Si–O–C bond is crucial for the formation of silicone composites. Catalyst-mediated silylesterification is useful in creating Si–O–C bonds because it is cost-effective and uses a hydrosilane precursor of lower reactivity than that of chlorosilane. However, it was previously demonstrated that two important silylesterification catalysts (zinc chloride and Karstedt’s catalyst) exhibit different selectivity for oxidized functional groups that are present on the surface of CNTs after oxidative acid treatment. This report details the selective modification of CNTs with various oxygenated functional groups (aromatic and nonaromatic alcohols, carboxylic acids, ethers, and ketones) using diazonium chemistry. Modified CNTs were used to assess the specifity of zinc chloride and Karstedt’s catalyst for oxygenated functional groups during a silylesterification reaction. Karstedt’s catalyst appeared to be widely applicable, allowing for the silylesterification of all of the aforementioned oxygenated functional groups. However, it showed lower efficacy for ethers and ketones. By contrast, zinc chloride was found to be very specific for nonaromatic carboxylic acids. This study also examined the Hansen solubility parameters of modified CNTs.

AB - The functionalization of carbon nanotubes (CNTs) plays a key role in their solubilization and compatibility for many applications. Among the many possible ways to functionalize CNTs, the creation of an Si–O–C bond is crucial for the formation of silicone composites. Catalyst-mediated silylesterification is useful in creating Si–O–C bonds because it is cost-effective and uses a hydrosilane precursor of lower reactivity than that of chlorosilane. However, it was previously demonstrated that two important silylesterification catalysts (zinc chloride and Karstedt’s catalyst) exhibit different selectivity for oxidized functional groups that are present on the surface of CNTs after oxidative acid treatment. This report details the selective modification of CNTs with various oxygenated functional groups (aromatic and nonaromatic alcohols, carboxylic acids, ethers, and ketones) using diazonium chemistry. Modified CNTs were used to assess the specifity of zinc chloride and Karstedt’s catalyst for oxygenated functional groups during a silylesterification reaction. Karstedt’s catalyst appeared to be widely applicable, allowing for the silylesterification of all of the aforementioned oxygenated functional groups. However, it showed lower efficacy for ethers and ketones. By contrast, zinc chloride was found to be very specific for nonaromatic carboxylic acids. This study also examined the Hansen solubility parameters of modified CNTs.

KW - carbon nanotubes; aryl diazonium salts; silylesterification; hydrosilanes; zinc chloride; Karstedt’s catalyst; Hansen solubility parameters.

U2 - 10.3390/app10010109

DO - 10.3390/app10010109

M3 - Article

VL - 10

JO - Applied Sciences

JF - Applied Sciences

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