Chain-growth cationic polymerization of 2-halogenated thiophenes promoted by Brønsted acids

2014 ◽  
Vol 5 (20) ◽  
pp. 5928-5941 ◽  
Author(s):  
Arumugam Balasubramanian ◽  
Ting-Chia Ku ◽  
Hong-Pin Shih ◽  
Alishetty Suman ◽  
Huang-Jyun Lin ◽  
...  
Keyword(s):  
Cationic Polymerization ◽  
Chain Growth ◽  
Bronsted Acids

Brønsted acids are found to be effective and generally applicable catalysts for inducing the cationic chain-growth polymerization of a wide variety of 2-halogenated-3-substituted-thiophenes.

CATIONIC POLYMERIZATION OF ETHYLENE OXIDE: IV. THE PROPAGATION REACTIONS

1960 ◽  
Vol 38 (10) ◽  
pp. 1967-1975 ◽  
Author(s):  
G. T. Merrall ◽  
G. A. Latrémouille ◽  
A. M. Eastham
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Cationic Polymerization ◽  
Chain Growth ◽  
Low Molecular Weight ◽  
Boron Fluoride

Studies of the boron-fluoride-catalyzed reaction of ethylene oxide with simple alcohols and low molecular weight polyglycols indicate three ways in which chain growth could occur, but only one of these is considered to be important after the initial stages of polymerization. The rate of disappearance of monomer reaches a maximum at a molecular weight of about 400. A mechanism is proposed to account for both polymerization and depolymerization and it is shown how equilibrium between these two reactions could result.

Simultaneous step-growth and chain-growth cationic polymerization of styrenic monomers bearing carbazolyl groups

Polymer ◽  
2017 ◽  
Vol 129 ◽  
pp. 83-91 ◽  
Author(s):  
Irina V. Vasilenko ◽  
Aliaksei A. Vaitusionak ◽  
Jurgita Sutaite ◽  
Ausra Tomkeviciene ◽  
Jolita Ostrauskaite ◽  
...  
Keyword(s):  
Cationic Polymerization ◽  
Chain Growth ◽  
Step Growth

Activated monomer mechanism in the cationic polymerization of L,L-lactide

2012 ◽  
Vol 84 (10) ◽  
pp. 2081-2088 ◽  
Author(s):  
Malgorzata Basko
Keyword(s):  
Cationic Polymerization ◽  
Ring Opening ◽  
Active Species ◽  
Degree Of Polymerization ◽  
Ion Trapping ◽  
Chain Growth ◽  
Hydroxyl Groups ◽  
Oxonium Ions ◽  
Trapping Method ◽  
Cationic Ring Opening Polymerization

Cationic polymerization of L,L-lactide (LA) in the presence of trifluoromethanesulfonic acid (TfA) has been studied. It was found that propagation proceeds mainly according to the activated monomer (AM) mechanism. Hydroxyl groups required for this type of propagation are formed as a result of the ring opening of protonated lactide. Thus, part of the acid (acting as an initiator) is consumed for the generation of hydroxyl groups, and part (acting as a catalyst) is involved in the protonation of monomer molecules forming secondary oxonium ions which are then able to react with the hydroxyl groups. A dual role of the protic acid is reflected in the kinetic results and in the dependence of experimental degree of polymerization on theoretical values. The structure of active species responsible for polymer chain growth was determined by phosphorus ion-trapping method. The evidence that in the cationic ring-opening polymerization (ROP) of LA initiated by protic acids, both hydroxyl groups and secondary oxonium ions are present throughout the polymerization (as required for polymerization proceeding by the AM mechanism) was found on the basis of changes of the averaged proton chemical shift in 1H NMR spectra of LA polymerizing mixture.

Epoxy-titania composites of cationic polymerization: synthesis conditions and properties

2015 ◽  
Vol 37 (4) ◽  
pp. 402-407
Author(s):  
S.V. Zhil’tsova ◽  
◽  
V.M. Mikhal’chuk ◽  
N.G. Leonova ◽  
R.I. Lyga ◽  
...  
Keyword(s):  
Cationic Polymerization ◽  
Synthesis Conditions

One-Pot Synthesis and Conformational Analysis of 6-Membered Cyclic Iodonium Salts

2020 ◽  
Author(s):  
Lucien Caspers ◽  
Julian Spils ◽  
Mattis Damrath ◽  
Enno Lork ◽  
Boris Nachtsheim
Keyword(s):  
Conformational Analysis ◽  
Bronsted Acids ◽  
One Pot ◽  
Benzyl Alcohols ◽  
Iodonium Salts ◽  
Efficient Approach ◽  
One Pot Synthesis ◽  
Diaryliodonium Salts

In this article we describe an efficient approach for the synthesis of cyclic diaryliodonium salts. The method is based on benzyl alcohols as starting materials and consists of an Friedel-Crafts-arylation/oxidation sequence. Besides a deep optimization, particluar focusing on the choice and ratios of the utilized Bronsted-acids and oxidants, we explore the substrate scope of this transformation. We also discuss an interesting isomerism of cyclic iodonium salts substituted with aliphatic substituents at the bridge head carbon. <br>

Carbon Chain Growth by Sequential Reactions of CO and CO2 with a Transition Metal Carbonyl Complex

2018 ◽  
Author(s):  
Richard Kong ◽  
Mark Crimmin
Keyword(s):  
Transition Metal ◽  
Metal Carbonyl ◽  
Carbon Chain ◽  
Chain Growth ◽  
Carbonyl Complex ◽  
Fischer Tropsch ◽  
Carbon Chains ◽  
Sequential Coupling ◽  
Energy Economy ◽  
Sequential Reactions

<i>The formation of carbon chains by the coupling of COx (X = 1 or 2) units on transition metals is a fundamental step relevant to Fischer-Tropsch catalysis. Fischer-Tropsch catalysis produces energy dense liquid hydrocarbons from synthesis gas (CO and H2) and has been a mainstay of the energy economy since its discovery nearly a century ago. Despite detailed studies aimed at elucidating the steps of catalysis, experimental evidence for chain growth (Cn to Cn+1 ; n > 2) from the reaction of CO with metal complexes is unprecedented. In this paper, we show that carbon chains can be grown from sequential reactions of CO or CO2 with a transition metal carbonyl complex. By exploiting the cooperative effect of transition and main group metals, we document the first example of chain propagation from sequential coupling of CO units (C1 to C3 to C4), along with the first example of incorporation of CO2 into the growing carbon chain.</i><br>

Polymer Chemistry

2004 ◽  
Keyword(s):  
Conducting Polymers ◽  
Liquid Crystalline ◽  
Polymer Chemistry ◽  
Chain Growth ◽  
Crystalline Polymers ◽  
Wide Range ◽  
Cyclic Oligomers ◽  
Step Growth

Polymer Chemistry: A Practical Approach in Chemistry has been designed for both chemists working in and new to the area of polymer synthesis. It contains detailed instructions for preparation of a wide-range of polymers by a wide variety of different techniques, and describes how this synthetic methodology can be applied to the development of new materials. It includes details of well-established techniques, e.g. chain-growth or step-growth processes together with more up-to-date examples using methods such as atom-transfer radical polymerization. Less well-known procedures are also included, e.g. electrochemical synthesis of conducting polymers and the preparation of liquid crystalline elastomers with highly ordered structures. Other topics covered include general polymerization methodology, controlled/"living" polymerization methods, the formation of cyclic oligomers during step-growth polymerization, the synthesis of conducting polymers based on heterocyclic compounds, dendrimers, the preparation of imprinted polymers and liquid crystalline polymers. The main bulk of the text is preceded by an introductory chapter detailing some of the techniques available to the scientist for the characterization of polymers, both in terms of their chemical composition and in terms of their properties as materials. The book is intended not only for the specialist in polymer chemistry, but also for the organic chemist with little experience who requires a practical introduction to the field.

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