scholarly journals Copolymerization of Phthalic Anhydride with Epoxides Catalyzed by Amine-bis(phenolate) Chromium(III) Complexes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1785
Author(s):  
Wiktor Bukowski ◽  
Agnieszka Bukowska ◽  
Aleksandra Sobota ◽  
Maciej Pytel ◽  
Karol Bester
Keyword(s):  
Phthalic Anhydride ◽  
Styrene Oxide ◽  
Glycidyl Ether ◽  
Molar Ratio ◽  
Phenyl Glycidyl Ether ◽  
Cyclohexene Oxide ◽  
Catalytic Systems ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Organic Bases

The effect of ligand structure on the catalytic activity of amine-bis(phenolate) chromium(III) complexes in the ring-opening copolymerization of phthalic anhydride and a series epoxides was studied. Eight complexes differing in the donor-pendant group (R1) and substituents (R2) in phenolate units were examined as catalysts of the model reaction between phthalic anhydride and cyclohexane oxide in toluene. They were used individually or as a part of the binary catalytic systems with nucleophilic co-catalysts. The co-catalyst was selected from the following organic bases: PPh3, DMAP, 1-butylimidazole, or DBU. The binary catalytic systems turned out to be more active than the complexes used individually, and DMAP proved to be the best choice as a co-catalyst. When the molar ratio of [PA]:[epoxide]:[Cr]:[DMAP] = 250:250:1:1 was applied, the most active complex (R1-X = CH2NMe2, R2 = F) allowed to copolymerize phthalic anhydride with differently substituted epoxides (cyclohexene oxide, 4-vinylcyclohexene oxide, styrene oxide, phenyl glycidyl ether, propylene oxide, butylene oxide, and epichlorohydrin) within 240 min at 110 °C. The resulting polyesters were characterized by Mn up to 20.6 kg mol−1 and narrow dispersity, and they did not contain polyether units.

scholarly journals Chromium-Salophen as a Soluble or Silica-Supported Co-Catalyst for the Fixation of CO2 Onto Styrene Oxide at Low Temperatures

2021 ◽  
Vol 9 ◽  
Author(s):  
Matthieu Balas ◽  
Ludivine K/Bidi ◽  
Franck Launay ◽  
Richard Villanneau
Keyword(s):  
Styrene Oxide ◽  
Initial Pressure ◽  
Amide Bond ◽  
Molar Ratio ◽  
Silica Support ◽  
Co Catalyst ◽  
Calculated Binding Energy ◽  
Co Catalysts ◽  
Styrene Epoxide ◽  
Styrene Carbonate

Addition of a soluble or a supported CrIII-salophen complex as a co-catalyst greatly enhances the catalytic activity of Bu4NBr for the formation of styrene carbonate from styrene epoxide and CO2. Their combination with a very low co-catalyst:Bu4NBr:styrene oxide molar ratio = 1:2:112 (corresponding to 0.9 mol% of CrIII co-catalyst) led to an almost complete conversion of styrene oxide after 7 h at 80°C under an initial pressure of CO2 of 11 bar and to a selectivity in styrene carbonate of 100%. The covalent heterogenization of the complex was achieved through the formation of an amide bond with a functionalized {NH2}-SBA-15 silica support. In both conditions, the use of these CrIII catalysts allowed excellent conversion of styrene already at 50°C (69 and 47% after 24 h, respectively, in homogeneous and heterogeneous conditions). Comparison with our previous work using other metal cations from the transition metals particularly highlights the preponderant effect of the nature of the metal cation as a co-catalyst in this reaction, that may be linked to its calculated binding energy to the epoxides. Both co-catalysts were successfully reused four times without any appreciable loss of performance.

Positive effects of a halloysite-supported Cu/Co catalyst fabricated by a urea-driven deposition precipitation method on the CO-SCR reaction and SO2 poisoning

2021 ◽  
Author(s):  
Wei-Jing Li ◽  
Shu Tsai ◽  
Ming-Yen Wey
Keyword(s):  
Co Oxidation ◽  
Catalytic Reduction ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Halloysite Nanotube ◽  
Co Catalyst ◽  
Reduction Of No ◽  
Co Catalysts ◽  
Positive Effects ◽  
So2 Poisoning

Cu/Co catalysts were prepared on halloysite nanotube supports by a urea-driven deposition-precipitation method for CO oxidation and the selective catalytic reduction of NO (CO-SCR). First, the Cu/NH3 molar ratio was...

scholarly journals Zinc Amido-Oxazolinate Catalyzed Ring Opening Copolymerization and Terpolymerization of Maleic Anhydride and Epoxides

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4044
Author(s):  
Muneer Shaik ◽  
Vamshi K. Chidara ◽  
Srinivas Abbina ◽  
Guodong Du
Keyword(s):  
Maleic Anhydride ◽  
Ring Opening ◽  
Styrene Oxide ◽  
Glycidyl Ether ◽  
Thermal Characterization ◽  
Relative Activity ◽  
Phenyl Glycidyl Ether ◽  
Scanning Calorimetry ◽  
The Difference ◽  
Block Terpolymers

Ring opening copolymerization (ROCOP) of epoxides and cyclic anhydrides has become an attractive approach for the synthesis of biodegradable polyesters with various compositions. Encouraged by the efficiency and versatility of a series of amido-oxazolinate zinc complexes, in this study they were shown to be active catalysts for the synthesis of unsaturated polyesters via ROCOP of maleic anhydride and various epoxides. The relative activity of epoxides in these reactions was observed to be styrene oxide > cyclohexene oxide > phenyl glycidyl ether, which could be correlated with the electronic and steric features of the substrate. To provide more structural possibilities for the polyesters, the difference in epoxide reactivity was exploited in an attempt to prepare block terpolymers from one anhydride and two epoxides. Terpolymerization was carried out in one or two steps in a single pot. The thermal characterization by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques suggested that the resulting materials were mostly random terpolymers.

scholarly journals Selective production of mono-aromatics from lignocellulose over Pd/C catalyst: the influence of acid co-catalysts

2017 ◽  
Vol 202 ◽  
pp. 141-156 ◽  
Author(s):  
Xiaoming Huang ◽  
Xianhong Ouyang ◽  
Bart M. S. Hendriks ◽  
O. M. Morales Gonzalez ◽  
Jiadong Zhu ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Fractionation Process ◽  
Catalytic Systems ◽  
Promising Alternative ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Speed Up ◽  
Metal Triflates ◽  
Pretreatment Technology ◽  
Glyceryl Trioleate

The ‘lignin-first’ approach has recently gained attention as an alternative whole biomass pretreatment technology with improved yield and selectivity of aromatics compared with traditional upgrading processes using technical lignins. Metal triflates are effective co-catalysts that considerably speed up the removal of lignin fragments from the whole biomass. As their cost is too high in a scaled-up process, we explored here the use of HCl, H2SO4, H3PO4 and CH3COOH as alternative acid co-catalysts for the tandem reductive fractionation process. HCl and H2SO4 were found to show superior catalytic performance over H3PO4 and CH3COOH in model compound studies that simulate lignin–carbohydrate linkages (phenyl glycoside, glyceryl trioleate) and lignin intralinkages (guaiacylglycerol-β-guaiacyl ether). HCl is a promising alternative to the metal triflates as a co-catalyst in the reductive fraction of woody biomass. Al(OTf)3 and HCl, respectively, afforded 46 wt% and 44 wt% lignin monomers from oak wood sawdust in tandem catalytic systems with Pd/C at 180 °C in 2 h. The retention of cellulose in the solid residue was similar.

Alternating Ring-Opening Copolymerization of Cyclohexene Oxide and Maleic Anhydride with Diallyl-Modified Manganese(III)–Salen Catalysts

2016 ◽  
Vol 69 (1) ◽  
pp. 47 ◽  
Author(s):  
Dengfeng Liu ◽  
Zhao Zhang ◽  
Xingmei Zhang ◽  
Xingqiang Lü
Keyword(s):  
Maleic Anhydride ◽  
Ring Opening ◽  
Monomer Conversion ◽  
Catalytic Performance ◽  
Chain Growth ◽  
Cyclohexene Oxide ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Polymer Chain Growth ◽  
Catalytic Performances

A series of diallyl-modified (salen)MnIII complexes have been designed, synthesized, and applied in the cyclohexene oxide and maleic anhydride ring-opening copolymerization. The experimental results show that these complexes are effective in the presence of co-catalyst 4-(dimethylamino)pyridine (DMAP). Of all the five catalysts, the catalyst (salcyen)MnCl (salcyen = 2-((E)-(2-((E)-5-allyl-2-hydroxy-3-methoxybenzylideneamino)cyclohexylimino)methyl)-4-allyl-6-methoxyphenol) exhibited the best catalytic performance under the conditions applied, and the cyclohexane of diimine bridge is conjugated with the two diallyl-salen-type moieties. This conjugation can increase the electron density of the centre MnIII cation so that catalyst (salcyen)MnCl favours the formation of reaction intermediates. Moreover, the anion effect of Cl– is proved to be the best in the catalytic performances. Among the three co-catalysts (DMAP, triphenylphosphine (Ph3P), and tetra-n-butylammonium bromide (n-Bu4NBr)) tested, DMAP is the most efficient towards monomer conversion and polymer chain growth.

scholarly journals One-pot Synthesis of Carbon-doped TiO2 with Bimetallic Ni-Ag co-catalysts in Photodegradation of Methylene Blue under UV and Visible Irradiation

2019 ◽  
Vol 15 (1) ◽  
pp. 35-42
Author(s):  
Kurnia Putri ◽  
Annisa Annisa ◽  
Sadang Husain ◽  
Rodiansono Rodiansono
Keyword(s):  
Photocatalytic Activity ◽  
High Photocatalytic Activity ◽  
Main Phase ◽  
Molar Ratio ◽  
Visible Range ◽  
Hydrothermal Conditions ◽  
One Pot ◽  
Tio2 Sample ◽  
Co Catalyst ◽  
Co Catalysts

Carbon modified-titanium dioxide (@C-TiO2) was prepared by one-pot procedure from TiCl4 and glucose under hydrothermal conditions at 150 ºC for 24 hours. The obtained @C-TiO2 was employed as support for Ni-Ag(3.0)@C-TiO2 nanocomposite (3.0 is the Ni/Ag molar ratio). The synthesized catalysts were characterized by means of XRD and UV-Vis DRS Spectroscopy. The XRD patterns of @TiO2 show the brookite as the main phase, meanwhile the main phase in the @C-TiO2, Ni-Ag(3.0)@TiO2 and Ni-Ag(3.0)@C-TiO2 nanocomposites were anatase. The band gap of the TiO2 sample slightly shifted to the visible range after the addition of C dopant or Ni-Ag(3.0) co-catalyst as indicated by UV-Vis DRS spectra. Ni-Ag(3.0)@C-TiO2 catalyst showed high photocatalytic activity for photodegradation of MB under both UV and visible irradiations at 60 ºC within 2 hours with maximum MB conversion of 67.5% and 54.1%, respectively. The synergistic action of C dopant or Ni-Ag(3.0) co-catalyst is believed to be important in the improvement of photocatalytic activity of @TiO2. Copyright ©2019 BCREC Group. All rights reserved 

scholarly journals Ring-Opening Copolymerization of Cyclohexene Oxide and Cyclic Anhydrides Catalyzed by Bimetallic Scorpionate Zinc Catalysts

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1651
Author(s):  
Felipe de la Cruz-Martínez ◽  
Marc Martínez de Sarasa Buchaca ◽  
Almudena del Campo-Balguerías ◽  
Juan Fernández-Baeza ◽  
Luis F. Sánchez-Barba ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Catalytic System ◽  
Phthalic Anhydride ◽  
Ring Opening ◽  
High Selectivity ◽  
Zinc Complexes ◽  
Cyclohexene Oxide ◽  
Reaction Conditions ◽  
Cyclic Anhydrides

The catalytic activity and high selectivity reported by bimetallic heteroscorpionate acetate zinc complexes in ring-opening copolymerization (ROCOP) reactions involving CO2 as substrate encouraged us to expand their use as catalysts for ROCOP of cyclohexene oxide (CHO) and cyclic anhydrides. Among the catalysts tested for the ROCOP of CHO and phthalic anhydride at different reaction conditions, the most active catalytic system was the combination of complex 3 with bis(triphenylphosphine)iminium as cocatalyst in toluene at 80 °C. Once the optimal catalytic system was determined, the scope in terms of other cyclic anhydrides was broadened. The catalytic system was capable of copolymerizing selectively and efficiently CHO with phthalic, maleic, succinic and naphthalic anhydrides to afford the corresponding polyester materials. The polyesters obtained were characterized by spectroscopic, spectrometric, and calorimetric techniques. Finally, the reaction mechanism of the catalytic system was proposed based on stoichiometric reactions.

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