Polyurethane foams (PUFs) are a significant group of polymeric foam materials. Thanks to their ou... more Polyurethane foams (PUFs) are a significant group of polymeric foam materials. Thanks to their outstanding mechanical, chemical, and physical properties, they are implemented successfully in a wide range of applications. Conventionally, PUFs are obtained in polyaddition reactions between polyols, diisoycyanate, and water to get a CO2 foaming agent. The toxicity of isocyanate has attracted considerable attention from both scientists and industry professionals to explore cleaner synthesis routes for polyurethanes excluding the use of isocyanate. The polyaddition of cyclic carbonates (CCs) and polyfunctional amines in the presence of an external blowing agent or by self-blowing appears to be the most promising route to substitute the conventional PUFs process and to produce isocyanate-free polyurethane foams (NIPUFs). Especially for polyhydroxyurethane foams (PHUFs), the use of a blowing agent is essential to regenerate the gas responsible for the creation of the cells that are the bas...
Foam products are one of the largest markets for polyurethane (PU) and are heavily used in many s... more Foam products are one of the largest markets for polyurethane (PU) and are heavily used in many sectors. However, current PU formulations use highly toxic and environmentally unfriendly production processes. Meanwhile, the increasing environmental concerns and regulations are intensifying the research into green and non-toxic products. In this study, we synthesized flexible polyurethane foam (PUF) using different weight percentages (0.025%, 0.05% and 0.1%) of a non-toxic bismuth catalyst. The bismuth-catalyzed foams presented a well evolved cellular structure with an open cell morphology. The properties of the bismuth-catalyzed flexible PUF, such as the mechanical, morphological, kinetic and thermal behaviors, were optimized and compared with a conventional tin-catalyzed PUF. The bismuth-catalyst revealed a higher isocyanate conversion efficiency than the stannous octoate catalyst. When comparing samples with similar densities, the bismuth-catalyzed foams present better mechanical b...
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
2017 International Renewable and Sustainable Energy Conference (IRSEC), 2017
Natural polymers, especially polysaccharides, are explored for application in heterogeneous catal... more Natural polymers, especially polysaccharides, are explored for application in heterogeneous catalysis as immobilization support for metallic or organometallic catalysts. In this work, we designed a green Pd(0) based supported catalyst for Heck C-C coupling reactions. The support was produced from Nanofibrillated Cellulose (NFC) extracted from the rachis of date palm tree. The NFC was prepared by mechanical and chemical pretreatment by mean of TEMPO oxidation of the palm tree cellulose pulp. The Pd(0)-supNFC catalyst was characterized by mean of FTIR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and elementary analysis (EDX), and tested on Heck cross-coupling reaction in comparison with Pd(OAc)2 with the same reaction under homogeneous conditions. Notable properties were found: eco-friendly processing, good reaction yields, very short reaction times, easy separation and reusability with insignificant loss of catalytic activity. More precisely the catalytic tests showed that the Pd(0)-supNFC catalyst has an excellent reactivity with a high reaction yield (90%) with low catalyst loading and short time reaction. In addition, the catalyst retained its activity even after three cycles.
IOP Conference Series: Materials Science and Engineering, 2020
In this study, a cellulose nanomaterial (Cellulose nanofiber, CNF) was employed as solid support ... more In this study, a cellulose nanomaterial (Cellulose nanofiber, CNF) was employed as solid support and stabilizing agent for the highly active cobalt nanoparticles via in situ green and facile synthesis as an environmentally benign supported catalyst. The process of preparation involves the reduction of cobalt precursors on the surface of CNF in ambient conditions with the presence of NaBH4. The structure of the synthesized organic-inorganic hybrid Co/CNF was characterized by field emission scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The hybrid aerogel nanocomposite Co/CNF demonstrated excellent catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in water with NaBH4. Even with a very low amount of catalyst and was found to be good enough to achieve 100% reduction of 4-NP with a higher reaction rate (in 8 min). The heterogeneous nanocomposite catalyst was easily isolated from the reaction mix...
In an attempt to improve anticancer activity, a series of retinoids–chromene hybrids was describe... more In an attempt to improve anticancer activity, a series of retinoids–chromene hybrids was described. The novel heterocyclic chromene–retinoids hybrid including oxygen as a heteroatom in a six‐membered cyclic ring (2H‐chromene or 2H‐1‐benzopyran) was designed and synthesized by introducing different groups such as an aromatic or styrylphenyl ring in 6‐position of 2H‐chromene. These novel compounds were synthesized by using the efficient cascades one‐pot process involving Wittig–Horner–Emmons reaction and Suzuki–Miyaura cross‐coupling pallado‐catalyzed reactions with 60% to 90% overall yields. These new compounds were tested against glioblastoma multiforme brain cancer, medulloblastoma, neuroblastoma cell lines, and breast cancer MCF‐7 cell lines. Two of them exhibited an appreciable anti‐tumor activity in the low micromolar range, which opens new perspectives for therapeutic application on humans.
A three-component, one-pot, stepwise Sonogashira–heterocyclization–Heck-coupling process was dev... more A three-component, one-pot, stepwise Sonogashira–heterocyclization–Heck-coupling process was developed starting from either haloarenecarboxamides, halophenols or haloanilines, terminal alkynes and electron-deficient alkenes. Cyclic imidate-, benzofuran-, or indole-type products are obtained, respectively, in useful yields, being typically better than those obtained with isolation of the intermediate Sonogashira adducts. Very high 6-endo selectivity is maintained with imidate-type coupling products despite the presence of copper salts carried over from the Sonogashira coupling.
Polyurethane foams (PUFs) are a significant group of polymeric foam materials. Thanks to their ou... more Polyurethane foams (PUFs) are a significant group of polymeric foam materials. Thanks to their outstanding mechanical, chemical, and physical properties, they are implemented successfully in a wide range of applications. Conventionally, PUFs are obtained in polyaddition reactions between polyols, diisoycyanate, and water to get a CO2 foaming agent. The toxicity of isocyanate has attracted considerable attention from both scientists and industry professionals to explore cleaner synthesis routes for polyurethanes excluding the use of isocyanate. The polyaddition of cyclic carbonates (CCs) and polyfunctional amines in the presence of an external blowing agent or by self-blowing appears to be the most promising route to substitute the conventional PUFs process and to produce isocyanate-free polyurethane foams (NIPUFs). Especially for polyhydroxyurethane foams (PHUFs), the use of a blowing agent is essential to regenerate the gas responsible for the creation of the cells that are the bas...
Foam products are one of the largest markets for polyurethane (PU) and are heavily used in many s... more Foam products are one of the largest markets for polyurethane (PU) and are heavily used in many sectors. However, current PU formulations use highly toxic and environmentally unfriendly production processes. Meanwhile, the increasing environmental concerns and regulations are intensifying the research into green and non-toxic products. In this study, we synthesized flexible polyurethane foam (PUF) using different weight percentages (0.025%, 0.05% and 0.1%) of a non-toxic bismuth catalyst. The bismuth-catalyzed foams presented a well evolved cellular structure with an open cell morphology. The properties of the bismuth-catalyzed flexible PUF, such as the mechanical, morphological, kinetic and thermal behaviors, were optimized and compared with a conventional tin-catalyzed PUF. The bismuth-catalyst revealed a higher isocyanate conversion efficiency than the stannous octoate catalyst. When comparing samples with similar densities, the bismuth-catalyzed foams present better mechanical b...
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
2017 International Renewable and Sustainable Energy Conference (IRSEC), 2017
Natural polymers, especially polysaccharides, are explored for application in heterogeneous catal... more Natural polymers, especially polysaccharides, are explored for application in heterogeneous catalysis as immobilization support for metallic or organometallic catalysts. In this work, we designed a green Pd(0) based supported catalyst for Heck C-C coupling reactions. The support was produced from Nanofibrillated Cellulose (NFC) extracted from the rachis of date palm tree. The NFC was prepared by mechanical and chemical pretreatment by mean of TEMPO oxidation of the palm tree cellulose pulp. The Pd(0)-supNFC catalyst was characterized by mean of FTIR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and elementary analysis (EDX), and tested on Heck cross-coupling reaction in comparison with Pd(OAc)2 with the same reaction under homogeneous conditions. Notable properties were found: eco-friendly processing, good reaction yields, very short reaction times, easy separation and reusability with insignificant loss of catalytic activity. More precisely the catalytic tests showed that the Pd(0)-supNFC catalyst has an excellent reactivity with a high reaction yield (90%) with low catalyst loading and short time reaction. In addition, the catalyst retained its activity even after three cycles.
IOP Conference Series: Materials Science and Engineering, 2020
In this study, a cellulose nanomaterial (Cellulose nanofiber, CNF) was employed as solid support ... more In this study, a cellulose nanomaterial (Cellulose nanofiber, CNF) was employed as solid support and stabilizing agent for the highly active cobalt nanoparticles via in situ green and facile synthesis as an environmentally benign supported catalyst. The process of preparation involves the reduction of cobalt precursors on the surface of CNF in ambient conditions with the presence of NaBH4. The structure of the synthesized organic-inorganic hybrid Co/CNF was characterized by field emission scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The hybrid aerogel nanocomposite Co/CNF demonstrated excellent catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in water with NaBH4. Even with a very low amount of catalyst and was found to be good enough to achieve 100% reduction of 4-NP with a higher reaction rate (in 8 min). The heterogeneous nanocomposite catalyst was easily isolated from the reaction mix...
In an attempt to improve anticancer activity, a series of retinoids–chromene hybrids was describe... more In an attempt to improve anticancer activity, a series of retinoids–chromene hybrids was described. The novel heterocyclic chromene–retinoids hybrid including oxygen as a heteroatom in a six‐membered cyclic ring (2H‐chromene or 2H‐1‐benzopyran) was designed and synthesized by introducing different groups such as an aromatic or styrylphenyl ring in 6‐position of 2H‐chromene. These novel compounds were synthesized by using the efficient cascades one‐pot process involving Wittig–Horner–Emmons reaction and Suzuki–Miyaura cross‐coupling pallado‐catalyzed reactions with 60% to 90% overall yields. These new compounds were tested against glioblastoma multiforme brain cancer, medulloblastoma, neuroblastoma cell lines, and breast cancer MCF‐7 cell lines. Two of them exhibited an appreciable anti‐tumor activity in the low micromolar range, which opens new perspectives for therapeutic application on humans.
A three-component, one-pot, stepwise Sonogashira–heterocyclization–Heck-coupling process was dev... more A three-component, one-pot, stepwise Sonogashira–heterocyclization–Heck-coupling process was developed starting from either haloarenecarboxamides, halophenols or haloanilines, terminal alkynes and electron-deficient alkenes. Cyclic imidate-, benzofuran-, or indole-type products are obtained, respectively, in useful yields, being typically better than those obtained with isolation of the intermediate Sonogashira adducts. Very high 6-endo selectivity is maintained with imidate-type coupling products despite the presence of copper salts carried over from the Sonogashira coupling.
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