Synthesis and characterization of mesoporous silica SBA-15 functionalized by mono-, di-, and tri-amine and its catalytic behavior towards Michael addition

Aykut

2020

Applied Organom Chemis

The main objective of this study is to develop readily accessible and recyclable solid catalysts for enantioselective reactions. To achieve this, magnetic MCM‐41 and non‐magnetic SBA‐15 mesoporous supports were prepared, then mesoporous silica supported chiral urea‐amine bifunctional catalysts were synthesized by grafting of chiral urea‐amine ligand onto SBA‐15 and magnetic MCM‐41. The magnetic and non‐magnetic supports and so‐prepared solid catalysts were characterized by using different methods such as N2 sorption measurements, Fourier transform infrared spectroscopy (FT‐IR), field emission scanning electron microscope‐energy dispersive X‐ray analysis (FESEM‐EDX), X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). Results showed that (1R, 2R) or (1S, 2S)‐1,2‐diphenylethane‐1,2‐diamine was successively immobilized onto magnetic MCM‐41 and SBA‐15 pores. The heterogeneous chiral solid catalysts and their homogenous counterparts exhibited high activities both enantioselective transfer hydrogenation reaction (up to 99% conversion and 65% ee) and enantioselective Michael reaction (up to 98% conversion and 26% ee). Moreover, the SBA‐15 supported solid catalysts were separated from the reaction mixture by simple filtration, whereas the magnetic MCM‐41 supported solid catalysts were separated by simple magnetic decantation and reused in three consecutive catalytic experiments.

Section: Resultsmentioning

confidence: 94%

Readily accessible mesoporous silica nanoparticles supported chiral urea‐amine bifunctional catalysts for enantioselective reactions

Aykut

2020

Applied Organom Chemis

Journal of Molecular Structure

“…Among the materials suitable for adsorption of CO 2 , there are mesoporous silicas (such as SBA-15, MCM-48 and MCM-41) which have interesting physico-chemical properties [5,11,[22][23][24][25][26][27][28]. They are useful for a large number of applications mainly due to their high surface areas and large pore sizes.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…The mesoporous silica SBA-15 was prepared hydrothermally using TEOS as a silica source, P123 as a structuring agent. The preparation method was well described in our previously published work [5,11,25,27]. The calcined mesoporous silica SBA-15 has been functionalized by different aminosilanes according to the method described in the literature [5,27] According to the literature, the functionalized materials were treated in a 100 mL of solution containing Cu(NO 3 ) 2 (1M) [5].…”

Section: Preparation Of Adsorbentsmentioning

confidence: 99%

Mesoporous silica supported amine and amine-copper complex for CO2 adsorption: Detailed reaction mechanism of hydrophilic character and CO2 retention

Boukoussa

Hakiki

Bouazizi

et al. 2019

Self Cite

The mesoporous silica SBA-15 functionalized with various amines was prepared and then doped with copper (Cu ++). The modified materials were tested for the retention of CO 2 at room temperature using temperature-programmed desorption (CO 2-TPD). Several parameters affecting the CO 2 retention capacity (CRC) were investigated such as effect of the nature of amine groups, repetitive adsorption-desorption cycles and dispersion of copper. CO 2-TPD and H 2 O-TPD were employed in order to correlate the hydrophilic character with the CO 2 retention capacity. The obtained results showed that amines-functionalized mesoporous materials containing their own moisture have good results towards the retention of CO 2. Especially the triamine-functionalized SBA-15 has the greatest CRC value which results in the increase of the number of adsorption sites. The reuse of these solids in three adsorption/desorption cycles showed higher stability with a slight decrease in CRC. The dispersion of copper showed a progressive decrease in the CRC value. The correlation between the Cu% and the CRC shows that the value of the CRC decreases with increasing Cu% due to complexation of the adsorption sites (amines) by acid sites (copper).

“…Though these linkers yield the primary amine FSs, silica can also be functionalized with secondary, and tertiary amines . The organosilanes possessing the multiple amine sites are relatively longer than APTES/APTMS, keeping the catalytic active site quite far from silica surface . Note that the length of organosilanes can tune the catalytic activity of resultant FS supported catalysts to some extent .…”

Section: Conventional Fss: Types and Their Chemical Modificationsmentioning

confidence: 99%

Functionalized Silicas for Metal‐Free and Metal‐Based Catalytic Applications: A Review in Perspective of Green Chemistry

Antony

Marimuthu

Yang

et al. 2019

The Chemical Record

Heterogeneous catalysis plays a key role in promoting green chemistry through many routes. The functionalizable reactive silanols highlight silica as a beguiling support for the preparation of heterogeneous catalysts. Metal active sites anchored on functionalized silica (FS) usually demonstrate the better dispersion and stability due to their firm chemical interaction with FSs. Having certain functional groups in structure, FSs can act as the useful catalysts for few organic reactions even without the need of metal active sites which are termed as the covetous reusable organocatalysts. Magnetic FSs have laid the platform where the effortless recovery of catalysts is realized just using an external magnet, resulting in the simplified reaction procedure. Using FSs of multiple functional groups, we can envisage the shortened reaction pathway and, reduced chemical uses and chemical wastes. Unstable bio‐molecules like enzymes have been stabilized when they get chemically anchored on FSs. The resultant solid bio‐catalysts exhibited very good reusability in many catalytic reactions. Getting provoked from the green chemistry aspects and benefits of FS‐based catalysts, we confer the recent literature and progress focusing on the significance of FSs in heterogeneous catalysis. This review covers the preparative methods, types and catalytic applications of FSs. A special emphasis is given to the metal‐free FS catalysts, multiple FS‐based catalysts and magnetic FSs. Through this review, we presume that the contribution of FSs to green chemistry can be well understood. The future perspective of FSs and the improvements still required for implementing FS‐based catalysts in practical applications have been narrated at the end of this review.