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.

Ring-opening copolymerization of epoxide and dianhydride in the presence of manganese(III) asymmetrical bis-Schiff base catalysts

2014 ◽  
Vol 92 (11) ◽  
pp. 1098-1105 ◽  
Author(s):  
Deng-Feng Liu ◽  
Lu-Qun Zhu ◽  
Jing Wu ◽  
Li-Ying Wu ◽  
Xing-Qiang Lü
Keyword(s):  
Schiff Base ◽  
Ring Opening ◽  
Monomer Conversion ◽  
Structure Design ◽  
Steric Effects ◽  
Chain Growth ◽  
Electronic Effects ◽  
Reaction Conditions ◽  
Base Catalysts ◽  
Electronic And Steric Effects

Based on a series of asymmetrical bis-Schiff base H2Ln (n = 1–4) ligands with different electronic and steric effects, a series of [Mn(Ln)Cl] complexes 1–4 are obtained and shown to be effective catalysts in ring-opening copolymerization of epoxides and dianhydrides. Through the structure design, the input of electron-withdrawing bromine substituent para to the phenoxide group of the complexes is considerately beneficial to the improved activities. Moreover, steric and electronic effects of the suitable MeO substituent at the ortho orientation on the phenoxide group may both play a role in the formation of alternating ring-opening copolymers under the identical reaction conditions. In three cocatalysts tested, n-Bu4NBr is positive to monomer conversion and chain growth of polymer.

Ring-opening copolymerization of CHO (cyclohexene oxide) and MA (maleic anhydride) catalyzed by the Co(III)–Salalen complex

2014 ◽  
Vol 48 ◽  
pp. 69-72 ◽  
Author(s):  
Xingmei Zhang ◽  
Yaoju Liu ◽  
Yan Chen ◽  
Zhao Zhang ◽  
Daidi Fan ◽  
...  
Keyword(s):  
Maleic Anhydride ◽  
Ring Opening ◽  
Cyclohexene Oxide

Ring-opening polymerization of ethylene carbonate using ionic liquids as catalysts

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiancheng Zhou ◽  
Ling Cheng ◽  
Dongfang Wu
Keyword(s):  
Ionic Liquids ◽  
Ring Opening ◽  
Ethylene Carbonate ◽  
Molar Fraction ◽  
Reaction System ◽  
Monomer Conversion ◽  
Catalytic Performance ◽  
Ring Opening Polymerization ◽  
Polymerization Catalysts ◽  
Chain Cleavage

AbstractThe ring-opening polymerization of ethylene carbonate was examined using ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and 1-butyl-3-methylimidazolium chlorozincate ([bmim]Cl-(ZnCl2)x), as polymerization catalysts. It was shown that the polymerization was accompanied with decarboxylation and chain cleavage reaction. As the reaction time increased, the monomer conversion increased and the content of ethylene carbonate units in the resultant polymer decreased, while the polymer molecular weight increased at first, reached a maximum and then decreased. It was also found that not only the polymerizing activity of the [bmim]Cl-(ZnCl2)x but also its performance for suppressing the decarboxylation and chain cleavage increased with the molar fraction of ZnCl2. It was deduced that the catalytic performance of ionic liquids mainly depended on their inorganic anions and that the larger the amount of these anions in the reaction system, the better the catalytic performance. The polymerizing activity of ionic liquids was much higher than conventional catalysts often used for the polymerization of ethylene carbonate.

scholarly journals MIL-101(Cr) for CO2 Conversion into Cyclic Carbonates, Under Solvent and Co-Catalyst Free Mild Reaction Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 453
Author(s):  
Emmanuelia Akimana ◽  
Jichao Wang ◽  
Natalya V. Likhanova ◽  
Somboon Chaemchuen ◽  
Francis Verpoort
Keyword(s):  
Ring Opening ◽  
High Surface ◽  
High Surface Area ◽  
Strong Acid ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Cyclic Carbonates ◽  
Reaction Conditions ◽  
Co Catalyst ◽  
Strong Acid Sites

Mild reaction conditions (nearly room temperature and atmospheric CO2 pressure) for the cycloaddition of CO2 with epoxides to produce cyclic carbonates were investigated applying MIL-101(Cr) as a catalyst. The MIL-101 catalyst contains strong acid sites, which promote the ring-opening of the epoxide substrate. Moreover, the high surface area, enabling the adsorption of more CO2 (substrate), combined with a large pore size of the catalyst is essential for the catalytic performance. Additionally, epoxide substrates bearing electron-withdrawing substituents or having a low boiling point demonstrated an excellent conversion towards the cyclic carbonates. MIL-101(Cr) for the cycloaddition of carbon dioxide with epoxides is demonstrated to be a robust and stable catalyst able to be re-used at least five times without loss in activity.

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.

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 Efficient Production of Poly(Cyclohexene Carbonate) via ROCOP of Cyclohexene Oxide and CO2 Mediated by NNO-Scorpionate Zinc Complexes

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2148
Author(s):  
Sonia Sobrino ◽  
Marta Navarro ◽  
Juan Fernández-Baeza ◽  
Luis F. Sánchez-Barba ◽  
Agustín Lara-Sánchez ◽  
...  
Keyword(s):  
Ring Opening ◽  
Zinc Complexes ◽  
Efficient Production ◽  
Cyclohexene Oxide ◽  
X Ray Diffraction ◽  
Co Catalyst ◽  
X Ray ◽  
Mild Conditions ◽  
High Yields ◽  
Very High

New mono- and dinuclear chiral alkoxide/thioalkoxide NNO-scorpinate zinc complexes were easily synthesized in very high yields, and characterized by spectroscopic methods. X-ray diffraction analysis unambiguously confirmed the different nuclearity of the new complexes as well as the variety of coordination modes of the scorpionate ligands. Scorpionate zinc complexes 2, 4 and 6 were assessed as catalysts for polycarbonate production from epoxide and carbon dioxide with no need for a co-catalyst or activator under mild conditions. Interestingly, at 70 °C, 10 bar of CO2 pressure and 1 mol % of loading, the dinuclear thioaryloxide [Zn(bpzaepe)2{Zn(SAr)2}] (4) behaves as an efficient and selective one-component initiator for the synthesis of poly(cyclohexene carbonate) via ring-opening copolymerization of cyclohexene oxide (CHO) and CO2, affording polycarbonate materials with narrow dispersity values.

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