Ring-Opening Polymerization of L-lactide Initiated by Samarium(III) Acetate

2019 ◽  
Vol 3 (2) ◽  
pp. 112-119
Author(s):  
Jesús Miguel Contreras Ramírez ◽  
Dimas Medina ◽  
Francisco López-Carrasquero ◽  
Ricardo Rafael Contreras
Keyword(s):  
1H Nmr ◽  
Ring Opening ◽  
Alkali Metals ◽  
Molar Mass ◽  
Ring Opening Polymerization ◽  
Solvent Free ◽  
Size Exclusion ◽  
Polymerization Process ◽  
Molar Ratio ◽  
Aliphatic Polyesters

Background: The synthesis of the aliphatic polyesters obtained by the ring opening polymerization has been achieved using as initiators a large amount of organometallic compounds derivative from: Alkali metals, alkaline earth metals, transition metals and lanthanide metals. Of all these compounds, the lanthanide derivatives have acquired great importance in the synthesis of aliphatic polyesters, since these show a greater catalytic activity and also can provide polymer with characteristics that will be very useful in the design of biomaterials. Objective: It was proposed the synthesis of poly(L-lactida) (PL-LA) through a ring opening polymerization process of L-lactide initiated with samarium(III) acetate (Sm(OAc)3) under solvent-free melt conditions. The influence of different parameters of reaction, such as temperature, time, molar ratio monomer to initiator, on typical variables of polymers, e.g., conversion, dispersity, and molar mass, were analyzed. Methods: All polymerizations were carried out under solvent-free melt conditions in ampoules-like flasks, equipped with a magnetic stirrer. The obtained polyesters were characterized by size exclusion chromatography (SEC) and 1H-NMR. Results: The Sm(OAc)3 induces the polymerization of L-LA at high conversion, and produce polyesters with number-average molecular weights of 1.00 x 103 to 30.00 x 103 Dalton. The 1H-NMR analysis indicates a typical polymerization mechanism of coordination-insertion, with a breakdown of the acyl-oxygen bond of the L-LA. Conclusion: Sm(OAc)3 was an effective initiator for the ring-opening polymerization of L-LA. SEC chromatography showed that, at high temperatures and prolonged reaction times, the molar mass of the polyester decreases, which is associated with the transesterification collateral reactions that occur during the polymerization process.

scholarly journals Synthesis and characterization of poly(1-methyltrimethylene carbonate) (PMTMC) by mean ring-opening polymerization

2020 ◽  
Vol 5 (3) ◽  
pp. 21
Author(s):  
Jesús Miguel Contreras Ramírez ◽  
Meribary Monsalve
Keyword(s):  
Ring Opening ◽  
Molar Mass ◽  
Thermal Polymerization ◽  
Ring Opening Polymerization ◽  
Active Species ◽  
Size Exclusion ◽  
Polymerization Process ◽  
Molar Ratio ◽  
Molecular Characteristics ◽  
Ft Ir

  In this work, the activity of samarium (III) acetate (Sm(OAc)3) was evaluated as a possible initiator in the ring opening polymerization (ROP) of 1-methyltrimethylene carbonate (MTMC). The effects of temperature (Tr) and monomer-initiator molar ratio (M/I) on the molecular characteristics (conversion, dispersity, and molar mass) of the polymers obtained were analyzed. The reaction temperature was varied between 90 and 160 °C and the molar ratio M/I between 200 and 1000. The molar mass of the products was obtained by size exclusion chromatography (SEC), while its structure was analyzed using FT-IR and 1H-NMR spectroscopy. Thermal polymerization experiments (in the absence of an initiator) were performed in order to evaluate the effectiveness of the initiator. The comparison between the thermal polymerization of MTMC and its polymerization in the presence of Sm(OAc)3, suggests that acetate has very low catalytic activity as the initiator of the ROP of PMTMC. The molar masses of the polymers obtained ranged between 6000 and 10000 Dalton, and the monomer to polymer conversions varied between 9 and 30 %. SEC chromatograms showed monomodal and symmetric curves, suggesting that only one type of active species participates in the polymerization process. Based on the structural analysis, a polymerization mechanism was proposed in which the water possibly acts as the only active species that initiates the reaction.   Palabra clave: Samarium (III) acetate, ring-opening polymerization, 1-methyltrimethylenecarbonate, poly(1-methyltrimethylenecarbonate).   Abstract En este trabajo se evaluó la actividad del acetato de samario (III) (Sm(OAc)3) como posible iniciador en la polimerización de apertura de anillo (PAA) del carbonato de 1-metiltrimetileno (MTMC). Se analizaron los efectos de la temperatura (Tr) y relación molar monómero-iniciador (M/I) sobre las características moleculares (conversión, dispersidad y masa molar) de los polímeros obtenidos. La temperatura de reacción se varió entre 90 y 160 °C y la relación molar M/I entre 200 y 1000. La masa molar de los productos se obtuvo mediante cromatografía de exclusión por tamaño, mientras que su estructura fue analizada mediante espectroscopia FT-IR y 1H-RMN. Además, se realizaron algunos experimentos de polimerización térmica (en ausencia de iniciador) que sirvieron de referencia para evaluar la efectividad del iniciador. La comparación de los resultados obtenidos en la polimerización térmica y en presencia del Sm(OAc)3 indicó que este último presenta muy poca actividad catalítica como iniciador de la PAA de PMTMC. Las masas molares de los polímeros obtenidos oscilaron entre 6000 y 10000 Dalton, mientras que las conversiones de monómero a polímero variaron entre 9 y 30%. Los cromatogramas SEC mostraron curvas mono-modales y simétricas, indicando que en el proceso de polimerización participa un solo tipo de especie activa. En base al análisis estructural, mediante técnicas espectroscópicas, se propuso un mecanismo de reacción para la polimerización en la que el agua posiblemente actúa como la única especie activa iniciadora de la reacción.   Keywords: Acetato de samario (III), polimerización por apertura de anillo, 1-metiltrimetilencarbonato, poli(1-metiltrimetilencarbonato).  

scholarly journals Studying the Ring-Opening Polymerization of 1,5-Dioxepan-2-one with Organocatalysts

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1642
Author(s):  
Jinbao Xu ◽  
Yang Chen ◽  
Wenhao Xiao ◽  
Jie Zhang ◽  
Minglu Bu ◽  
...  
Keyword(s):  
Size Exclusion Chromatography ◽  
1H Nmr ◽  
Ring Opening ◽  
Nmr Spectra ◽  
Kinetic Studies ◽  
Ring Opening Polymerization ◽  
1H Nmr Spectra ◽  
Size Exclusion ◽  
Reaction Conditions ◽  
Exclusion Chromatography

Three different organocatalysts, namely, 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris (dimethylamino) phosphoranylidenamino]-2Λ5,4Λ5-catenadi(phosphazene) (t-BuP4), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), have been used as 1,5-dioxepan-2-one (DXO) ring-opening polymerization (ROP) catalysts at varied reaction conditions. 1H NMR spectra, size exclusion chromatography (SEC) characterizations, and kinetic studies prove that the (co)polymerizations are proceeded in a controlled manner with the three organocatalysts. It is deduced that t-BuP4 and DBU catalysts are in an initiator/chain end activated ROP mechanism and TBD is in a nucleophilic ROP mechanism.

Synthesis of Rare Earth Catalyst LLa[N(TMS)2]•DME(L=3,5-But2-2-HO-C6H2CH-NH-C5H4N) and Catalytic Behavior for Polymerization of Rac-Lactide

2012 ◽  
Vol 184-185 ◽  
pp. 1302-1306
Author(s):  
Xi Zhu ◽  
Yao Rong Wang
Keyword(s):  
Rare Earth ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Molar Ratio ◽  
Elimination Reaction ◽  
Catalytic Behavior ◽  
Rare Earth Catalyst

A dianionic phenoxyamido ligand was the first to be used to stabilize organo-rare-earth mental amido complex. Amine elimination reaction of La[N(SiMe3)2]3(THF)2 with 3,5-But2-2-HO-C6H2CH-NH-C5H4N in a 1 : 1 molar-ratio gave the anionic phenoxyamido neodymium amide LLa[N(TMS)2]•DME (1) in a high isolated yield. Furthemore, the catalytic behavior of complex 1 for the ring-opening polymerization of rac-lactide was explored.

Organotin-bridged ionic liquid as a solvent-free, leaching-resistive catalyst for ring opening polymerization of ε-caprolactone

2019 ◽  
Vol 43 (15) ◽  
pp. 5872-5878 ◽  
Author(s):  
Asmaa Bouyahya ◽  
Sébastien Balieu ◽  
Redouane Beniazza ◽  
Mustapha Raihane ◽  
Abdelkrim El Kadib ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Solvent Free ◽  
Biologically Relevant ◽  
The Way

An easy synthesis provides a monoalkyltin trichloride grafted onto an ionic liquid. The catalyst paves the way to nontoxic biologically relevant materials.

scholarly journals Ring-opening polymerization of monosubstituted oxiranes in the presence of potassium hydride: determination of initiation course and structure of macromolecules by MALDI-TOF mass spectrometry

2019 ◽  
Vol 26 (12) ◽  
Author(s):  
Zbigniew Grobelny ◽  
Justyna Jurek-Suliga ◽  
Sylwia Golba
Keyword(s):  
Mass Spectrometry ◽  
Ring Opening ◽  
Glycidyl Ether ◽  
Ring Opening Polymerization ◽  
Size Exclusion ◽  
Oxirane Ring ◽  
Maldi Tof ◽  
Glycidyl Ethers ◽  
Initiation Step ◽  
Potassium Hydride

AbstractSeveral monosubstituted oxiranes were polymerized with suspension of potassium hydride (KH) in tetrahydrofuran (THF) at room temperature. This heterogeneous process resulted in polyethers with various starting groups depending on the kind of monomer. The macromolecules formed in ring-opening polymerization of monosubstituted oxiranes were analyzed by Matrix Assisted Laser Desorption/Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS). It was stated, that initiation of propylene oxide (PO) polymerization with KH proceeded via three ways, i.e. cleavage of oxirane ring in the β-position, monomer deprotonation and deoxygenation. Potassium isopropoxide, potassium allyloxide and potassium hydroxide were the real initiators. The main reactions, which occur in the initiation step, depend on the type of monomer used. In the case of allyl glycidyl ether (AGE) and phenyl glycidyl ether (PGE) deprotonation of the monomer did not occur. During initiation of glycidyl ethers oxirane ring was opened and also linear ether bond between glycidyl group and oxygen atom was cleaved under influence of KH. Interestingly, formation of new kinds of macromolecules was observed in the systems containing glycidyl ethers, which do not possess mers of the monomers used. Mechanisms of the studied processes were presented and discussed. Carbon-13 Nuclear Magnetic Resonance (13C NMR) was used as supporting technique for analysis of the obtained polymers. Number average molar masses of the polymers (Mn) determined by Size Exclusion Chromatography (SEC) were about two times higher than calculated ones. It indicated that half of used KH did not take part in the initiation step.

scholarly journals Synthesis of Biodegradable Polymers: A Review on the Use of Schiff-Base Metal Complexes as Catalysts for the Ring Opening Polymerization (ROP) of Cyclic Esters

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 800 ◽  
Author(s):  
Orlando Santoro ◽  
Xin Zhang ◽  
Carl Redshaw
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Base Metal ◽  
Biodegradable Polymers ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Polymerization Process ◽  
Cyclic Esters ◽  
Recent Advances ◽  
Schiff Base Metal Complexes

This review describes the recent advances (from 2008 onwards) in the use of Schiff-base metal complexes as catalysts for the ring opening polymerization (ROP) of cyclic esters. The synthesis and structure of the metal complexes, as well as all aspects concerning the polymerization process and the characteristics of the polymers formed, will be discussed.

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