scholarly journals Simultaneous Adsorption and Reduction of Cr(VI) to Cr(III) in Aqueous Solution Using Nitrogen-Rich Aminal Linked Porous Organic Polymers

2021 ◽  
Vol 13 (2) ◽  
pp. 923
Author(s):  
Muhammad A. Sabri ◽  
Ziad Sara ◽  
Mohammad H. Al-Sayah ◽  
Taleb H. Ibrahim ◽  
Mustafa I. Khamis ◽  
...  
Keyword(s):  
Active Sites ◽  
Condensation Reaction ◽  
Significant Loss ◽  
Single Step ◽  
High Porosity ◽  
Organic Polymers ◽  
Porous Organic Polymers ◽  
One Pot ◽  
Surface Areas ◽  
Redox Active

Two novel nitrogen-rich aminal linked porous organic polymers, NRAPOP-O and NRAPOP-S, have been prepared using a single step-one pot Schiff-base condensation reaction of 9,10-bis-(4,6-diamino-S-triazin-2-yl)benzene and 2-furaldehyde or 2-thiophenecarboxaldehyde, respectively. The two polymers show excellent thermal and physiochemical stabilities and possess high porosity with Brunauer–Emmett–Teller (BET) surface areas of 692 and 803 m2 g−1 for NRAPOP-O and NRAPOP-S, respectively. Because of such porosity, attractive chemical and physical properties, and the availability of redox-active sites and physical environment, the NRAPOPs were able to effectively remove Cr(VI) from solution, reduce it to Cr(III), and simultaneously release it into the solution. The efficiency of the adsorption process was assessed under various influencing factors such as pH, contact time, polymer dosage, and initial concentration of Cr(VI). At the optimum conditions, 100% removal of Cr(VI) was achieved, with simultaneous reduction and release of Cr(III) by NRAPOP-O with 80% efficiency. Moreover, the polymers can be easily regenerated by the addition of reducing agents such as hydrazine without significant loss in the detoxication of Cr(VI).

scholarly journals New dicationic DABCO-based ionic liquids: a scalable metal-free one-pot synthesis of bis-2-amino-5-arylidenethiazol-4-ones

2019 ◽  
Vol 6 (7) ◽  
pp. 190997 ◽  
Author(s):  
Wael A. A. Arafa ◽  
Asmaa K. Mourad
Keyword(s):  
Knoevenagel Condensation ◽  
Condensation Reaction ◽  
Significant Loss ◽  
Single Step ◽  
Scale Production ◽  
Reaction Conditions ◽  
One Pot ◽  
Dicationic Ionic Liquid ◽  
Knoevenagel Condensation Reaction ◽  
Green Conditions

Herein, a novel DABCO-based dicationic ionic liquid (bis-DIL) was easily prepared from the sonication of DABCO with 1,3-dichloro-2-propanol and then characterized by several techniques. Thereafter, under the ultimate green conditions, the performance of the bis-DIL was examined for the sono-synthesis of a new library of bis-2-amino-5-arylidenethiazol-4-ones via one-pot pseudo-five-component Knoevenagel condensation reaction of appropriate dialdehydes, rhodanine and amines. This protocol is tolerant towards several mono- and dialdehydes, excellently high yielding and affording access to the desired products in a single step within a short reaction time. Compared with the conventional methodologies, the proposed method displayed several remarkable merits such as milder reaction conditions without any side product, green solvent media, recording well in a variety of green metrics and applicability in gram-scale production. The recyclability of the bis-DIL was also investigated with an average recovered yield of 97% for six sequential cycles without any significant loss of the activity.

Facile synthesis of porous organic polymers bifunctionalized with azo and porphyrin groups

RSC Advances ◽  
2015 ◽  
Vol 5 (119) ◽  
pp. 98508-98513 ◽  
Author(s):  
Xiaowei Jiang ◽  
Yunfei Liu ◽  
Jun Liu ◽  
Yali Luo ◽  
Yinong Lyu
Keyword(s):  
Polymer Networks ◽  
Direct Coupling ◽  
Porous Polymer ◽  
Organic Polymers ◽  
Facile Synthesis ◽  
Porous Organic Polymers ◽  
Aryl Amine ◽  
Catalyst Free ◽  
Surface Areas

Azo and porphyrin bifunctionalized porous polymer networks (azo-PPors) with BET surface areas up to 750 m2 g−1 were synthesized via a catalyst-free direct coupling of tetra(4-nitrophenyl)porphyrin and aryl amine monomers.

scholarly journals Combustion-Synthesized Porous CuO-CeO2-SiO2 Composites as Solid Catalysts for the Alkenylation of C(sp3)-H Bonds Adjacent to a Heteroatom via Cross-Dehydrogenative Coupling

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1252
Author(s):  
Ha V. Le ◽  
Vy B. Nguyen ◽  
Hai H. Pham ◽  
Khoa D. Nguyen ◽  
Phuoc H. Ho ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Coupling Reaction ◽  
Catalytic Performance ◽  
Composite Catalyst ◽  
High Porosity ◽  
One Pot ◽  
General Validity ◽  
Solid Catalysts ◽  
Surface Areas ◽  
Dehydrogenative Coupling

A series of mixed oxides of CuO, CeO2, and SiO2 were prepared by gel combustion and employed for the first time as efficient solid catalysts in a solvent-less liquid-phase cross-dehydrogenative coupling. The facile one-pot catalyst synthesis resulted in highly porous materials presenting large specific surface areas and strong metal–support interactions. The interaction with highly dispersed CeO2 enhanced the redox properties of the CuO species. The CuO-CeO2-SiO2 composites exhibited excellent catalytic performance for the selective coupling between 1,1-diphenylethylene and tetrahydrofuran with a yield up to 85% of 2-(2,2-diphenylvinyl)-tetrahydrofuran in the presence of di-tert-butyl peroxide (DTPB) and KI. Albeit both CuO and CeO2 species are proved to be responsible for the catalytic conversion, a great synergistic improvement in the catalytic activity was obtained by extended contact between the oxide phases by high porosity in comparison with the reactions using individual Cu or Ce catalysts. The activity of the composite catalyst was shown to be highly stable after five successive reaction cycles. Furthermore, the study scope was extended to the synthesis of different derivatives via composite-catalyzed coupling of C(sp2)-H with C(sp3-H) adjacent to a heteroatom. The good yields recorded proved the general validity of this composite for the cross-dehydrogenative coupling reaction rarely performed on solid catalysts.

Truxene-based porous polymers: from synthesis to catalytic activity

2018 ◽  
Vol 9 (36) ◽  
pp. 4585-4595 ◽  
Author(s):  
Jordy Guadalupe ◽  
Ana M. Ray ◽  
Eva M. Maya ◽  
Berta Gómez-Lor ◽  
Marta Iglesias
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Porous Polymers ◽  
Organic Polymers ◽  
Porous Organic Polymers ◽  
Surface Areas ◽  
Specific Surface Areas

New, robust, insoluble porous organic polymers based on the semiconducting platform of hexamethyltruxene with high Brunauer–Emmett–Teller specific surface areas and interesting catalytic activity are presented.

scholarly journals Amine-linked Covalent Organic Frameworks as a Powerful Platform for Post-Synthetic Modification: Structure Interconversion and Combined Linkage- and Pore-Wall-Modification

2020 ◽  
Author(s):  
Lars Grunenberg ◽  
Gökcen Savasci ◽  
Maxwell Terban ◽  
Viola Duppel ◽  
Igor Moudrakovski ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Hydrolytic Stability ◽  
Pore Wall ◽  
Single Step ◽  
Synthetic Methods ◽  
Secondary Amines ◽  
Covalent Organic Frameworks ◽  
One Pot ◽  
Surface Areas ◽  
Novel Strategy

<div>Covalent organic frameworks have emerged as a powerful synthetic platform for installing and interconverting dedicated molecular functions on a crystalline polymeric backbone with atomic precision. Here, we present a novel strategy to directly access amine-linked covalent organic frameworks, which serve as a scaffold enabling pore-wall modification and linkage-interconversion by new synthetic methods based on Leuckart-Wallach reduction with formic acid and ammonium formate. Frameworks connected entirely by secondary amine linkages, mixed amine/imine bonds, and partially formylated amine linkages are obtained in a single step from imine-linked frameworks, or directly from corresponding linkers in a one-pot crystallisation-reduction approach. The new, 2D amine-linked covalent organic frameworks, rPI-3-COF, rTTI-COF, and rPy1P-COF, are obtained with high crystallinity and large surface areas. Secondary amines, installed as reactive-sites on the pore wall, enable further post-synthetic functionalisation to access tailored covalent organic frameworks, with increased hydrolytic stability, as potential heterogeneous catalysts.</div>

scholarly journals Bifunctional Heterometallic Metal-Organic Frameworks for Solvent-Free Heterogeneous Cascade Catalysis

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 309 ◽  
Author(s):  
Mingming Zheng ◽  
Yanxiang Wang ◽  
Pingyun Feng
Keyword(s):  
Lewis Acids ◽  
Active Sites ◽  
Metal Organic Frameworks ◽  
Significant Loss ◽  
Solvent Free ◽  
Knoevenagel Reaction ◽  
One Pot ◽  
Free System ◽  
Metal Organic ◽  
The One

A family of heterometallic metal-organic frameworks (MOFs) (CPM200s) harmoniously coexisting as Lewis acids and base (azo) sites were prepared. Seven CPM200s were employed as multifunctional heterogeneous cascade catalysts for the one-pot deacetalization-Knoevenagel reaction in a solvent-free system. Benefiting from the cooperation between Lewis acids from the open metal sites and base sites from the ligands, the CPM200s showed high activity and selectivity for the tandem reaction. The heterometallic 3D porous framework reported here not only offers a combination of two opposite active sites in the same framework of materials but also increases mass transfer of the substrate, thus maximizing the efficiency and substrate selectivity of the bifunctional catalysts. The CPM200s showed the highest turnover frequency (TOF), outperforming that of the reported MOFs in tandem with the deacetalization-Knoevenagel reaction. A strong correlation between the TOF and charge-to-radius ratio (z/r) of metal ions in the CPM200s was observed for the first time. The bifunctional CPM200s catalysts can be reused five times without significant loss of activity.

scholarly journals Cyclotetrabenzil-Based Porous Organic Polymers with High Carbon Dioxide Affinity

2021 ◽  
Author(s):  
Timur Ashirov ◽  
Maymounah Alrayyani ◽  
Kyung Seob Song ◽  
Ognjen Miljanic ◽  
Ali Coskun
Keyword(s):  
Carbon Dioxide ◽  
Condensation Reaction ◽  
Building Blocks ◽  
Organic Polymer ◽  
Bet Surface Area ◽  
Chloride Salt ◽  
Organic Polymers ◽  
High Carbon ◽  
Porous Organic Polymers ◽  
High Carbon Dioxide

Porous organic polymers (POPs) incorporating macrocyclic units have been investigated in recent years in an effort to transfer macrocycles’ intrinsic host-guest properties onto the porous networks to achieve complex separations. In this regard, highly interesting building blocks are presented by the family of cyclotetrabenzoin macrocycles with rigid, well-defined, electron-deficient cavities. This macrocycle shows high affinity towards linear guest molecules such as carbon dioxide, thus offering an ideal building block for the synthesis of CO2-philic POPs. Herein, we report the synthesis of a porous organic polymer through the condensation reaction between cyclotetrabenzil with 1,2,4,5-tetraaminobenzene under ionothermal conditions using the eutectic zinc chloride/sodium chloride/potassium chloride salt mixture at 250 oC. Notably, following the condensation reaction, the macrocycle favors 3D growth rather than 2D one while retaining the cavity. The resulting polymer, named 3D-mPOP, showed a highly microporous structure with the BET surface area of 1142 m2 g−1 and a high carbon dioxide affinity with a binding enthalpy of 39 kJ mol−1. Moreover, 3D-mPOP showed very high selectivity for carbon dioxide in carbon dioxide/methane and carbon dioxide /nitrogen mixtures.

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