Ring-Opening Polymerization Reactions of ε-Caprolactone and Lactides Initiated by (Benzimidazolylmethyl)amino Magnesium(II) Alkoxides

2018 ◽  
Vol 71 (5) ◽  
pp. 341
Author(s):  
Ekemini D. Akpan ◽  
Bernard Omondi ◽  
Stephen O. Ojwach
Keyword(s):  
Ring Opening ◽  
Steric Effect ◽  
Kinetic Studies ◽  
Ring Opening Polymerization ◽  
Butyl Alcohol ◽  
Catalytic Activities ◽  
First Order ◽  
Molecular Weights ◽  
Tert Butyl Alcohol ◽  
Amine Ligands

Reactions of (benzimidazolylmethyl)amine ligands N-((1H-benzo[s]imidazol-2-yl)methyl)-2,6-dimethylaniline (L1), N-((1H-benzo[d]imidazol-2-yl)methyl)-2,6-diisopropylaniline (L2), and N-((1H-benzo[d]imidazol-2-yl)methyl)-2,4,6-trimethylaniline (L3) with Mg(nBu)2 in the presence of either benzyl alcohol (BnOH) or tert-butyl alcohol (t-BuOH) afforded the respective MgII alkoxides [Mg(L1)(OBn)]2 (1), [(Mg(L2)(OBn)]2 (2), [Mg(L3)(OBn)]2 (3), [Mg(L2)(t-BuO)]2 (4). Complexes 1–4 formed efficient catalysts for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL), d,l-lactide (d,l-LA) and l-lactide (l-LA) at 110°C. The catalytic activities of these complexes in the ROP reactions were influenced by the steric effect of the ligands. Kinetic studies showed pseudo-first-order dependency on monomer. Polycaprolactone and polylactides of moderate weight-average molecular weights of 15285 and 5200 g mol−1 and fairly narrow polydispersity indexes from 1.24 to 1.58 were produced.

Accelerated living cationic ring-opening polymerization of a methyl ester functionalized 2-oxazoline monomer

2015 ◽  
Vol 6 (4) ◽  
pp. 514-518 ◽  
Author(s):  
Petra J. M. Bouten ◽  
Dietmar Hertsen ◽  
Maarten Vergaelen ◽  
Bryn D. Monnery ◽  
Marcel A. Boerman ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Ring Opening ◽  
Kinetic Studies ◽  
Ring Opening Polymerization ◽  
Cationic Ring Opening Polymerization

Kinetic studies on the homo- and copolymerization of 2-methoxycarboxyethyl-2-oxazoline with 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline is discussed.

Anionic Ring-Opening Polymerization Simulations for Hyperbranched Polyglycerols with Defined Molecular Weights

2013 ◽  
Vol 46 (21) ◽  
pp. 8458-8466 ◽  
Author(s):  
Florian Paulus ◽  
Maximilian E. R. Weiss ◽  
Dirk Steinhilber ◽  
Anatoly N. Nikitin ◽  
Christof Schütte ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Molecular Weights ◽  
Anionic Ring

scholarly journals Synthesis and crossover reaction of TEMPO containing block copolymer via ROMP

2010 ◽  
Vol 6 ◽  
Author(s):  
Olubummo Adekunle ◽  
Susanne Tanner ◽  
Wolfgang H Binder
Keyword(s):  
Dicarboxylic Acid ◽  
Ring Opening ◽  
Laser Desorption ◽  
Ring Opening Polymerization ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Block Copolymerization ◽  
Molecular Weights ◽  
Ionization Mass Spectroscopy ◽  
Rate Of Polymerization

We report on the block copolymerization of two structurally different norbornene monomers (±)-endo,exo-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid dimethylester (7), and (±)-endo,exo-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid bis(1-oxyl-2,2,6,6-tetramethyl-piperidin-4-yl) ester (9) using ruthenium based Grubbs’ type initiators [(PCy3)2Cl2Ru(benzylidene)] G1 (PCy3 = tricyclohexylphosphine), [(H2IMes)(PCy3)Cl2Ru(benzylidene)] G2 (H2IMes = 1,3-bis(mesityl)-2-imidazolidinylidene), [(H2IMes)(py)2Cl2Ru(benzylidene)] G3 (py = pyridine or 3-bromopyridine) and Umicore type initiators [(PCy3)2Cl2Ru(3-phenylinden-1-ylidene)] U1 (PCy3 = tricyclohexylphosphine), [(H2IMes)(PCy3)Cl2Ru(3-phenylinden-1-ylidene)] U2 (H2IMes = 1,3-bis(mesityl)-2-imidazolidinylidene), [(H2IMes)(py)Cl2Ru(3-phenylinden-1-ylidene)] U3 (py = pyridine or 3-bromopyridine) via ring opening polymerization (ROMP). The crossover reaction and the polymerization kinetics were investigated using matrix assisted laser desorption ionization mass spectroscopy (MALDI-TOF) and nuclear magnetic resonance (NMR), respectively. MALDI showed that there was a complete crossover reaction after the addition of 25 equivalents of the second monomer. NMR investigation showed that U3 gave a faster rate of polymerization in comparison to U1. The synthesis of block copolymers with molecular weights up to M n = 31 000 g/mol with low polydispersities (M w/M n = 1.2) is reported.

THE DECOMPOSITION OF SILYL PEROXIDES

1964 ◽  
Vol 42 (5) ◽  
pp. 985-989 ◽  
Author(s):  
Richard R. Hiatt
Keyword(s):  
Thermal Decomposition ◽  
Rate Constant ◽  
Half Life ◽  
Order Rate Constant ◽  
Butyl Alcohol ◽  
Base Catalysis ◽  
First Order ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Acid And Base

The thermal decomposition of tert-butyl trimethylsilyl peroxide has been investigated and found to be sensitive to acid and base catalysis and to the nature of the solvent. In heptane and iso-octane the first-order rate constant could be expressed as 1.09 × 1015e−41200/RT and in 1-octene as 3.90 × 1015e−41200/RT (sec−1). The half life at 203 °C was about 1 hour. The reaction was faster in aromatic solvents; in chlorobenzene it was complicated by formation of HCl from the solvent.Products of the reaction were acetone, tert-butyl alcohol and hexamethyldisiloxane.

Radicals induced from peroxomonosulfate by nanoscale zero-valent copper in the acidic solution

2016 ◽  
Vol 74 (8) ◽  
pp. 1946-1952 ◽  
Author(s):  
Peng Zhou ◽  
Bei Liu ◽  
Jing Zhang ◽  
Yongli Zhang ◽  
Gucheng Zhang ◽  
...  
Keyword(s):  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Acidic Solution ◽  
Butyl Alcohol ◽  
First Order ◽  
First Order Kinetics ◽  
Tert Butyl Alcohol ◽  
Initial Ph ◽  
Reactive Radicals ◽  
Reactive Oxidant

A highly efficient advanced oxidation process for the degradation of benzoic acid (BA) during activation of peroxomonosulfate (PMS) by nanoscale zero-valent copper (nZVC) in acidic solution is reported. BA degradation was almost completely achieved after 10 min in the nZVC/PMS process at initial pH 3.0. PMS could accelerate the corrosion of nZVC in acidic to release Cu+ which can further activate PMS to produce reactive radicals. Both sulfate radical (SO4−•) and hydroxyl radical (•OH) were considered as the primary reactive oxidant in the nZVC/PMS process with the experiments of methyl (MA) and tert-butyl alcohol quenching. Acidic condition (initial pH ≤ 3.0) facilitated BA degradation and pH is a decisive factor to affect the oxidation capacity in the nZVC/PMS process. Moreover, BA degradation in the nZVC/PMS process followed the pseudo-first-order kinetics, and BA degradation efficiency increased with the increase of the nZVC dosage.

Structural and kinetic studies of the ring-opening polymerization of cyclic esters using N,N′ diarylformamidines Zn(II) complexes

Polyhedron ◽  
2016 ◽  
Vol 110 ◽  
pp. 63-72 ◽  
Author(s):  
Ekemini D. Akpan ◽  
Stephen O. Ojwach ◽  
Bernard Omondi ◽  
Vincent O. Nyamori
Keyword(s):  
Ring Opening ◽  
Kinetic Studies ◽  
Ring Opening Polymerization ◽  
Cyclic Esters

scholarly journals Ring-Opening Polymerization of ε-Caprolactone and Styrene Oxide–CO2 Coupling Reactions Catalyzed by Chelated Dehydroacetic Acid–Imine Aluminum Complexes

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 164
Author(s):  
Ting-Yen Wang ◽  
Yu-Chia Su ◽  
Bao-Tsan Ko ◽  
Yu Hsu ◽  
Yu-Fang Zeng ◽  
...  
Keyword(s):  
Ring Opening ◽  
Styrene Oxide ◽  
13C Nmr Spectroscopy ◽  
Ring Opening Polymerization ◽  
Coupling Reactions ◽  
1H And 13C Nmr ◽  
Excess Carbon ◽  
Catalytic Activities ◽  
Dehydroacetic Acid ◽  
Aluminum Compounds

A series of chelated dehydroacetic acid–imine-based ligands L1H~L4H was synthesized by reacting dehydroacetic acid with 2-t-butylaniline, (S)-1-phenyl-ethylamine, 4-methoxylbenzylamine, and 2-(aminoethyl)pyridine, respectively, in moderate yields. Ligands L1H~L4H reacted with AlMe3 in toluene to afford corresponding compounds AlMe2L1 (1), AlMe2L2 (2), AlMe2L3 (3), and AlMe2L4 (4). All the ligands and aluminum compounds were characterized by IR spectra, 1H and 13C NMR spectroscopy. Additionally, the ligands L1H~L4H and corresponding aluminum derivatives 1, 3, and 4 were characterized by single-crystal X-ray diffractometry. The catalytic activities using these aluminum compounds as catalysts for the ε-caprolactone ring-opening polymerization (ROP) and styrene oxide-CO2 coupling reactions were studied. The results show that increases in the reaction temperature and selective solvent intensify the conversions of ε-caprolactone to polycaprolactone. Regarding the coupling reactions of styrene oxide and CO2, the conversion rate is over 90% for a period of 12 h at 90 °C. This strategy dispenses the origination of cyclic styrene carbonates, which is an appealing concern because of the transformation of CO2 into an inexpensive, renewable and easy excess carbon feedstock.

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