Differences in Catalytic Activity of Poly(vinylamine) Introduced on Surface of Mesoporous SBA-15 by Grafting from and Grafting onto Methods in Knoevenagel Condensation

Wach, Anna; Drozdek, Marek; Dudek, Barbara; Biazik, Marta; Łątka, Piotr; Michalík, Marek; Kuśtrowski, Piotr

doi:10.1021/acs.jpcc.5b05868

Cited by 14 publications

(3 citation statements)

References 79 publications

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“…Introduction of basic species to porous supports is a regular method for the preparation of solid bases. Thus far, various materials have been employed as supports for solid bases, and the supports range from inorganic materials (such as alumina, zeolites, and mesoporous silicas) − to organic ones (such as porous organic polymers). − Apparently, supports have a significant effect on the surface properties and the catalytic activity of resultant solid bases.…”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Frameworks for Heterogeneous Basic Catalysis

et al. 2017

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Great attention has been given to metal-organic frameworks (MOFs)-derived solid bases because of their attractive structure and catalytic performance in various organic reactions. The extraordinary skeleton structure of MOFs provides many possibilities for incorporation of diverse basic functionalities, which is unachievable for conventional solid bases. The past decade has witnessed remarkable advances in this vibrant research area; however, MOFs for heterogeneous basic catalysis have never been reviewed until now. Therefore, a review summarizing MOFs-derived base catalysts is highly expected. In this review, we present an overview of the recent progress in MOFs-derived solid bases covering preparation, characterization, and catalytic applications. In the preparation section, the solid bases are divided into two categories, namely, MOFs with intrinsic basicity and MOFs with modified basicity. The basicity can originate from either metal sites or organic ligands. Different approaches used for generation of basic sites are included, and each approach is described with representative examples. The fundamental principles for the design and fabrication of MOFs with basic functionalities are featured. In the characterization section, experimental techniques and theoretical calculations employed for characterization of basic MOFs are summarized. Some representive experimental techniques, such as temperature-programmed desorption of CO (CO-TPD) and infrared (IR) spectra of different probing molecules, are covered. Following preparation and characterization, the catalytic applications of MOFs-derived solid bases are dealt with. These solid bases have potential to catalyze some well-known "base-catalyzed reactions" like Knoevenagel condensation, aldol condensation, and Michael addition. Meanwhile, in contrast to conventional solid bases, MOFs show some different catalytic properties due to their special structural and surface properties. Remarkably, characteristic features of MOFs-derived solid bases are described by comparing with conventional inorganic counterparts, keeping in mind the current opportunities and challenges in this field.

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Section: Introductionmentioning

confidence: 99%

Metal–Organic Frameworks for Heterogeneous Basic Catalysis

et al. 2017

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“…In our previous publication [13], we presented a comparison of the polyvinylamine-silica hybrid materials synthesized by two different techniques, namely "grafting from" and "grafting onto" method. The influence of the modification method on the catalytic activity in the Knoevenagel condensation between benzaldehyde and ethyl cyanoacetate was evidenced.…”

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confidence: 99%

Functionalization of mesoporous SBA-15 silica by grafting of polyvinylamine on epoxy-modified surface

Wach¹,

Natkański²,

Drozdek³

et al. 2017

Polimery

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Mesoporous SBA-15 silica was modified by grafting of 3-glycidoxypropyltrimethoxysilane (GPTMS). An influence of GPTMS/SBA-15 mass ratio used during this pre-functionalization step on the real amount of epoxy-silane grafted on the SBA-15 surface was studied by thermogravimetry and elemental analysis. The pre-functionalized SBA-15 was subsequently used to attach polyvinylamine (PVAm) chains by the opening of oxirane rings and the formation of bonds with NH 2 groups from PVAm. The yield of this process was determined. Furthermore, SEM (scanning electron microscopy), DRIFT (diffuse reflectance infrared Fourier transform spectroscopy) and XPS (X-ray photoelectron spectroscopy) as well as zeta potential measurements were applied to observe the changes in the chemical composition of SBA-15 surface and morphology of the synthesized materials. Various types of organic functionalities present on the modified SBA-15 were identified and analyzed quantitatively.

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“…Next, about 2 mL of PNIPAm-PAAm copolymer solution was added to the suspension in the presence of a trimethylamine catalyst and allowed to react at 40–70 °C for 24 h. During this reaction process, the amine (-NH 2 ) groups of PAAm can interact with the hydrogen groups of the opened epoxy ring via hydrogen bonding interactions between the amine part of the PAAm segment and the GPTMS units that were modified onto the outer surface of the mesoporous silica nanoparticles ( Scheme 1 , Step 2). Generally, this ring opening reaction requires a high temperature and catalytic conditions to perform a complete reaction [ 33 , 34 ]. However, in this work, an appropriate temperature condition was used to achieve a partial reaction to avoid the crowding accumulation of PNIPAm-PAAm copolymer onto the silica surfaces.…”

Section: Methodsmentioning

confidence: 99%

Thermosensitive Polymer-Modified Mesoporous Silica for pH and Temperature-Responsive Drug Delivery

Thirupathi¹,

Moorthy

Radhakrishnan

et al. 2023

Pharmaceutics

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A mesoporous silica-based drug delivery system (MS@PNIPAm-PAAm NPs) was synthesized by conjugating the PNIPAm-PAAm copolymer onto the mesoporous silica (MS) surface as a gatekeeper that responds to temperature and pH changes. The drug delivery studies are carried out in vitro at different pH (7.4, 6.5, and 5.0) and temperatures (such as 25 °C and 42 °C, respectively). The surface conjugated copolymer (PNIPAm-PAAm) acts as a gatekeeper below the lower critical solution temperature (LCST) (<32 °C) and as a collapsed globule structure above LCST (>32 °C), resulting in controlled drug delivery from the MS@PNIPAm-PAAm system. Furthermore, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cellular internalization results support the prepared MS@PNIPAm-PAAm NPs being biocompatible and readily taken up by MDA-MB-231 cells. The prepared MS@PNIPAm-PAAm NPs, with their pH-responsive drug release behavior and good biocompatibility, could be used as a drug delivery vehicle where sustained drug release at higher temperatures is required.

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Differences in Catalytic Activity of Poly(vinylamine) Introduced on Surface of Mesoporous SBA-15 by Grafting from and Grafting onto Methods in Knoevenagel Condensation

Cited by 14 publications

References 79 publications

Metal–Organic Frameworks for Heterogeneous Basic Catalysis

Metal–Organic Frameworks for Heterogeneous Basic Catalysis

Functionalization of mesoporous SBA-15 silica by grafting of polyvinylamine on epoxy-modified surface

Thermosensitive Polymer-Modified Mesoporous Silica for pH and Temperature-Responsive Drug Delivery

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