Octadecyl-modified silicas obtained by non-hydrolytic condensation of a C18-hybrid silica sol on a silica surface

Bernardes, Arthur A.; Emanuelli, Cezar A.; Cofferri, Patrícia; Netto, Antonio Marchi; Miranda, Milton Edson; Brambilla, Rodrigo; Santos, João Henrique Zimnoch dos

doi:10.1016/j.jnoncrysol.2017.03.033

Cited by 7 publications

(4 citation statements)

References 26 publications

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“…Also, materials with a higher content of organic groups usually present higher formation of less stressed 6‐fold siloxane rings, thereby allowing a better accommodation of these organic groups 26 . Similar results have already been reported for octadecyl‐modified silicas prepared by a non‐hydrolytic sol–gel approach 27 …”

Section: Resultssupporting

confidence: 76%

“…26 Similar results have already been reported for octadecylmodified silicas prepared by a non-hydrolytic sol-gel approach. 27 The ATR-FTIR results showed that the modification of silica with octadecyltrimethoxysilane, besides influencing the nature of surface species, also affects the structure of the silica network.…”

Section: Characteristics Of the Octadecylmodified Silicasmentioning

confidence: 99%

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Octadecyl‐modified silica supports for metallocene catalyst applied in ethylene polymerization

Bernardes

Zarth

Gossler

et al. 2020

J of Applied Polymer Sci

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Chemical modification of silica-based supports is an alternative route for modulating the active sites of metallocene catalysts, presenting the potential to obtain polyethylenes with improved properties. Therefore, this work investigates the effect of octadecylsilane content in silica support on the behavior of resulting supported metallocene catalysts on ethylene polymerization. For this propose, a series of octadecyl-modified silicas whit different amounts of octadecyl (ODS) groups were synthesized by a modified Stöber sol-gel method and then applied as supports for a metallocene catalyst. The supported metallocene catalysts were evaluated in ethylene polymerization and ethylene/1-hexene copolymerization reactions. Besides, studies of the growth kinetics of polyethylene particles in a gas phase reactor were performed using videomicroscopy. The octadecylsilane content in the supports was in the range of 0.2 to 1.4 mmol g −1. DRIFTS and 13 C CP/MAS NMR results showed a predominance of an all-trans octadecyl chain conformation. SEM images showed spherical particle morphology for silicas having octadecylsilane content up to 0.6 mmol g −1. The supported catalysts presented activity in ethylene polymerization in the range of 1100-1900 kg PE molZr −1 h −1 bar −1. The surface polarity of the catalyst influenced the molar mass of the resulting polyethylene. The increase of the ODS content on the silica surface led to a supported catalyst with slower kinetic behavior in the gas phase, which might be attributed to the diffusive effects of the octadecyl layer on the catalyst surface.

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Section: Resultssupporting

confidence: 76%

Section: Characteristics Of the Octadecylmodified Silicasmentioning

confidence: 99%

Octadecyl‐modified silica supports for metallocene catalyst applied in ethylene polymerization

Bernardes

Zarth

Gossler

et al. 2020

J of Applied Polymer Sci

Self Cite

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show abstract

“…35,36 Silica-based adsorbents are widely used for cleaning aqueous solutions in solid-phase extraction. 37 Silica modified with octadecyl groups improves the material's polarity in the extraction and separation of polar components. 37 There are no reported studies of the use of silica to remove 5-HMF and FF.…”

Section: Introductionmentioning

confidence: 99%

“…37 Silica modified with octadecyl groups improves the material's polarity in the extraction and separation of polar components. 37 There are no reported studies of the use of silica to remove 5-HMF and FF. However, previous studies indicate that silica has promising properties for the removal of compounds similar to 5-HMF and FF, including Brønsted-Lowry acidic analytes and polar compounds.…”

Section: Introductionmentioning

confidence: 99%

Detoxification of furanic aldehydes of the hemicellulosic hydrothermal hydrolysate of brewers’ spent grains by continuous adsorption on a fixed‐bed column

Torres-Mayanga

Castro

Azambuja

et al. 2023

Biofuels Bioprod Bioref

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During the process of subcritical water hydrolysis of lignocellulosic compounds, such as brewers' spent grains, some toxic compounds can be formed due to the breakdown of the cellulose structure. These compounds are known as furanic aldehydes, and they are inhibitors of microorganisms that are used in different processes, such as fermentation and anaerobic digestion, among others. The detoxification and conditioning of these hydrolysates are required before their use in other processes that require low concentrations of toxins. One of the mechanisms that can be used to diminish those compounds is the adsorption process. For this reason, this study evaluated at-line and in-line purification strategies using different adsorbents in fixed-bed columns to remove furanic aldehydes from a model feed simulating hydrolysate from subcritical water hydrolysis. The model feed consisted of simple sugars and furanic aldehydes at appropriate concentrations. The selected adsorbents were silica-C18, hydrocarbons, and activated carbon. The results indicate that, among the adsorbents that were studied, activated carbon was

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Hybrid vinyl silane and P123 template sol−gel derived carbon silica membrane for desalination

Yang

Wang

Motuzas

et al. 2017

J Sol-Gel Sci Technol

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Octadecyl-modified silicas obtained by non-hydrolytic condensation of a C18-hybrid silica sol on a silica surface

Cited by 7 publications

References 26 publications

Octadecyl‐modified silica supports for metallocene catalyst applied in ethylene polymerization

Octadecyl‐modified silica supports for metallocene catalyst applied in ethylene polymerization

Detoxification of furanic aldehydes of the hemicellulosic hydrothermal hydrolysate of brewers’ spent grains by continuous adsorption on a fixed‐bed column

Hybrid vinyl silane and P123 template sol−gel derived carbon silica membrane for desalination

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