Backbone‐assisted reactions of polymers. V. Kinetics of isomerization of poly(chloromethylthiirane) and poly(3‐chlorothietane) in solution

Abstract

The reversible isomerization of poly(chloromethylthiirane) and poly(3‐chlorothietane) represents a new kind of polymer reaction and a new method of copolymer synthesis. In chloroform, in dichloromethane, or in nitrobenzene the reaction is well described by reversible first‐order kinetics. A rate increase of ca. 40% on changing the solvent from chloroform to nitrobenzene is consistent with an isomerization mechanism that involves a rate‐determining attack of the backbone sulfur atom on the neighboring carbon‐chlorine bond and rapid ring‐opening of the thiiranium ion intermediate by chloride ion.

Synthesis and thermal properties of polythioether‐based liquid‐crystalline polymers containing azobenzene in the side chain

“…Therefore, the processes (steps 3 and 4) were carried out under the protection of nitrogen, and mercaptans were filtered quickly at low temperature (cooled with an ice‐bath and washed using ice‐water). Second, it has been reported that PCMT is rather unstable as regards its isomerization 21, 22. The subsequent reaction to yield copolymers, therefore, must be carried out at an appropriate time after formation of PCMT.…”

“…PCMT has not been used for the preparation of linear copolymers because of its complicated structure resulting from an unusual rearrangement at room temperature. Zussman and Tirrell proposed a likely mechanism for its isomerization, as shown in Scheme 21, 22. It was believed that the existing main form of PCMT were structures (a) and (b) for the fresh polymer and structure (c) appeared after three months.…”

“…The polychloromethylthiirane (PCMT) obtained from the polymerization of chloromethylthiirane at 0 °C using BF 3 ·Et 2 O as initiator is widely used to prepare chelating resins—crosslinked copolymers containing sulfur atoms 15, 16. Owing to the unusual structural rearrangement of PCMT at room temperature,21, 22 few attempts have been made to employ PCMT as the main chain of SLCPs. However, it was observed that PCMT has a relatively stable and clear structure under special conditions,20, 23 which gives the possibility for it to act as a main‐chain backbone of SCLCs.…”

Synthesis and application of modified poly (styrene‐alt‐maleic anhydride) networks as a nano chelating resin for uptake of heavy metal ions

“…Recently, poly (styrene‐alt‐maleic acid) has been synthesized and shown to be coordinated with metals through two carboxylic groups pertaining to two different polymer chains which indicate intermolecular complexation. Moreover, chelating resins with sulfur and nitrogen as donor atoms usually have excellent adsorption properties for mercury and noble metal ions …”

“…Moreover, chelating resins with sulfur and nitrogen as donor atoms usually have excellent adsorption properties for mercury and noble metal ions. [18,19] In this work, a new type of reactive copolymer has been synthesized by the modification of a linear copolymer of Poly (styrene-alt-maleic anhydride) by 3-aminobenzoic acid. The prepared resin has a good potential for crosslinking by 1, 2-diaminoethane and 1, 3-diaminopropane for the preparation of porous resin beads.…”