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.

scholarly journals SYNTHESIS AND NMR ANALYSIS OF THE STRUCTURE AND COMPOSITION OF TRIBLOCK POLY(ESTER-SILOXANE-ESTER) COPOLYMER BASED ON L-LACTIDE

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Milica Balaban ◽  
Nataša Sladojević ◽  
Vesna Antić
Keyword(s):  
Nmr Spectroscopy ◽  
Ring Opening ◽  
13C Nmr Spectroscopy ◽  
Ring Opening Polymerization ◽  
Dilute Solution ◽  
Nmr Analysis ◽  
1H And 13C Nmr ◽  
Influence Of Temperature ◽  
Dimethyl Siloxane ◽  
Dilute Solution Viscometry

The synthesis, structure and composition of triblock poly(ester-siloxane-ester) copolymers, PLLA-PDMS-PLLA, based on α,ω–diaminopropyl-poly(dimethyl siloxane) (PDMS) and L-lactide were studied in this work. The samples of the controlled block length were synthesized by ring-opening polymerization of L-lactide in the presence of stannous octoate, Sn(Oct)2, as a catalyst, and aminopropyl-terminated siloxane prepolymer, as a macroinitiator, in a concentrated toluene solution. Influence of temperature and concentration of the catalyst on the structure, composition and size of the copolymers were investigated by 1H and 13C NMR spectroscopy and dilute solution viscometry.

An Unprecedented Cyano-Induced Sodium Nitrite-Catalyzed C(sp3)-H and C(sp2)-H Coupling Reaction

2018 ◽  
Vol 15 (7) ◽  
pp. 989-994 ◽  
Author(s):  
Ling Li ◽  
Bo Su ◽  
Yuxiu Liu ◽  
Qingmin Wang
Keyword(s):  
Sodium Nitrite ◽  
Oxidative Coupling ◽  
High Resolution Mass Spectrometry ◽  
Coupling Reaction ◽  
13C Nmr Spectroscopy ◽  
Coupling Reactions ◽  
Reaction Conditions ◽  
1H And 13C Nmr ◽  
Oxidative Coupling Reaction ◽  
Oxidative Coupling Reactions

Aim and Objective: During the investigation of sodium nitrite-catalyzed oxidative coupling reaction of aryls, an unprecedented C(sp2)-H and C(sp3)-H coupling of substituted 2-aryl acetonitrile was found. Materials and Methods: The structure of the coupled product was confirmed by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry (HRMS), and comparison of its derivatives with known compounds. The effects of methoxy group in the benzene ring on the reaction were evaluated. Results: The optimized reaction conditions are summarized as follows: CF3SO3H/substrate = 1.5 equiv., NaNO2/substrate = 0.3 equiv., CH3CN as solvent. 2-(4-Methoxyphenyl)acetonitrile and 2-(3,4,5- trimethoxyphenyl)acetonitrile could also generate C(sp2)-H and C(sp3)-H coupling. The coupling reaction occurred as a typical radial mechanism. Conclusion: An unprecedented cyano-induced, NaNO2-catalyzed oxidative C(sp3)-H and C(sp2)-H coupling was reported. The reaction proceeded under very mild conditions, using O2 in the air as terminal oxidant. The unique oxidative manner might provide more inspiration for the development of intriguing oxidative coupling reactions.

Ring Opening Polymerization of ε-Caprolactone Catalyzed with Magnesium Lactate

2009 ◽  
Vol 610-613 ◽  
pp. 1208-1210 ◽  
Author(s):  
Lian Liu ◽  
Zhi Yong Wei ◽  
Pei Wang ◽  
Min Qi
Keyword(s):  
Nmr Spectroscopy ◽  
Reaction Temperature ◽  
13C Nmr ◽  
Ring Opening ◽  
Synthesis Method ◽  
13C Nmr Spectroscopy ◽  
Ring Opening Polymerization ◽  
Moderate Activity ◽  
Lactide Copolymers

The aim of this paper is to present a synthesis method of poly(ε-caprolactone) by the ring opening polymerization of ε-caprolactone catalyzed with nontoxic magnesium lactate. The results indicated that Mg(Lac)2 is a catalyst with moderate activity for the polymerization of ε-caprolactone. Effects of the catalyst and reaction temperatures on the microstructure of the ε-caprolactone and L-lactide copolymers were investigated by means of 13C-NMR spectroscopy. An increase in the reaction temperature enhances the role of transesterification and the extent of randomness.

scholarly journals SYNTHESIS, PREPARATIVE SEPARATION OF STRUCTURE ISOMERS AND PROPERTIES OF 2-(2-(DIALKYLAMINO)ETHYLAMINO)ETHANOLS OF ARYLALIPHATIC SERIES

2017 ◽  
Vol 12 (1) ◽  
pp. 57-63
Author(s):  
D. Q. Hoang ◽  
E. Ya. Borisova ◽  
N. Yu. Borisova ◽  
A. V. Krylov ◽  
N. A. Danilkin ◽  
...  
Keyword(s):  
Ring Opening ◽  
Room Temperature ◽  
Mixed Solvent ◽  
Sodium Hydroxide Solution ◽  
Styrene Oxide ◽  
Aqueous Sodium Hydroxide ◽  
Epoxide Ring ◽  
1H And 13C Nmr ◽  
Epoxide Ring Opening ◽  
Ft Ir

A method for the synthesis of 2-(2-(dialkylamino)ethylamino)ethanols based on the epoxide ring opening in styrene oxide by N,N-disubstituted ethylenediamines was developed. It is shown that the opening of the oxirane ring by diamines in 2-propanol at room temperature occurs mainly according to the Krasusky rule at the bond between the oxygen atom and the less substituted carbon atom. A mixture of two products with the predominance of the secondary diamino alcohol up to 82% was obtained. It was found that the separation of the products by distillation or recrystallization does not allow obtaining pure isomers. The mixture of isomers was converted into dihydrochlorides by dry HCl in dioxane and diethyl ether. Pure 2-(2-(dialkylamino)ethylamino)-1-phenylethanols and 2-(2-(dialkylamino)ethylamino)-2-phenylethanols were separated by the first fractional recrystallization of a mixture of diaminoalcohol dihydrochlorides from a mixed solvent followed by alkalization of the products with an aqueous sodium hydroxide solution. The diamino alcohols were characterized by FT-IR, 1H- and 13C-NMR and HRMS-ESI.

Yttrium and aluminium complexes bearing dithiodiolate ligands: synthesis and application in cyclic ester polymerization

2015 ◽  
Vol 44 (41) ◽  
pp. 17990-18000 ◽  
Author(s):  
A. Meduri ◽  
M. Cozzolino ◽  
S. Milione ◽  
K. Press ◽  
E. Sergeeva ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Cyclic Ester ◽  
Catalytic Activities

Yttrium and aluminium complexes of two dithiodiolate ligands that feature different bridges were synthesized and characterized. The catalytic activities of the four complexes in the ring-opening polymerization of ε-caprolactone and rac-lactide have been investigated.

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