Synthesis sulfonate monomers

Postsulfonation of polymers to form PEMs can lead to undesirable side reactions and may be hard to control on a repeatable basis. Synthesis of sulfonated macromolecules for use in PEMs by the direct reaction of sulfonated comonomers has gained attention as a rigorous method of controlling the chemical structure, acid content, and even molecular weight of these materials. While more challenging synthetically than postsulfonation, the control of the chemical nature of the polymer afforded by direct copolymerization of sulfonated monomers and the repeatability of the reactions allows researchers to gain a more systematic understanding of these materials properties. Sulfonated poly(arylene ether)s, sulfonated poly-(imide)s, and sulfonated poly(styrene) derivatives have been the most prevalent of the directly copolymerized materials. 

This chapter describes the synthesis, kinetics, and solution properties for copolymers ofN-vinylpyrrolidone (NVP) with sulfonate ionic and zwitterionic monomers. Examples of the sulfonate ionic monomers are sodium styrenesulfonate (NaSS) and sodium acrylamido-2-meth-ylpropanesulfonate (NaAMPS) an example of the zwitterionic sulfonate monomer is 2-hydroxyethyt)dimethyl(3-sulfopropyt)-ammonium inner salt, methacrylate (SPE). The NVP-NaAMPS monomer pair was exceptional, showing evidence for donor-acceptor character and an alternating tendency in copolymerization. The NVP copolymers containing simple sulfonate ionic monomers e.g., NaAMPS) showed polyelectrolyte solution properties. On the other hand, the NVP copolymers with zwitterionic sulfonate monomers showed antipoly electrolyte solution behavior. 

Poly(N-vinylpyrrolidone), P(NVP), is a nonionic, water-soluble polymer with high thermal and hydrolytic stability (7-9). Copolymers of N-vinylpyr-rolidone (NVP) with various carboxylate and carboxylate-precursor monomers (e.g., acrylic acid, sodium acrylate, crotonic acid, itaconic acid, and maleic anhydride) are also well-known (10). In addition, the homo- and copolymerization kinetics of these monomers are well-established. On the other hand, reports of copolymerizations of NVP with sulfonate monomers are sparse 11, 12). This chapter describes the synthesis, kinetics, and reactivity ratios for the copolymerization of NVP and some of the newer sulfonate monomers. A comparison of some of the solution properties for such copolymers is also included. 

The direct synthesis from a sulfonated monomer is more advantageous than the post-sulfonation method. In comparison to post-sulfonated material, the concentration as well as the positions of the sulfonate groups in the directly synthesized monomers can be more readily controlled. Further, the direct sulfonation method avoids crosslinking and other side reactions. This may result in a better thermal stability and in better mechanical properties. ... 

Recent efforts in the synthesis of sulfonated aromatic polymers are directed to the polymerization of sulfonated monomers (such as (b), (d), (g), (j), (k), and (1) shown in Scheme 3) [14,15,53,54,96-102] or coupling reactions of sulfonated compoimds with fimctional groups attached to a polymer backbone [ 103,104]. In post-sulfonation, attachment of the sulfonic acid group is restricted to the activated position ortho to the aromatic ether bond, as indicated in Scheme 4a, while in direct polymerization of sulfonated monomers, the sulfonic acid groups are attached to the deactivated site on the ring (Scheme 4b). An enhancement of stabUity toward desulfonation and a modestly higher acidity are expected for the structure shown in Scheme 4b. Recently, polymerization of sulfonated monomers was also used to obtain sulfonated polysulfone (m) via oxidation of a sulfonated polysulfide-polysulfone copolymer [105]. 

A large number of nonfluorinated polymers are now under investigation. Some of these activities have been reviewed in recent publications [165]. Approaches include the sulfonation of commercial polymers and the polymerization of new functionalized polymers. One of the first polymers chosen for sulfonation was polysulfone [166-174]. More recently the synthesis of stable polysulfones from sulfonated monomers has been explored [175]. 

Sulfonated monomers were also used for the synthesis of sulfonated poly-imides [123,124]. hi particular, sodium salt of the sulfonated bis-4-[(3-aminophenoxy)phenyl]phenylphosphine oxide was used for the preparation of sulfonated polyimides [123]. 

Figure 4.13 Synthesis of monomer sulfonated 3,4-ethyledioxythiophene. 1 thio-glycolic acid, 2 diethyl thiodiglycolate, 3 diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate disodium salt, 4 diethyl 3,4-dihydroxythiophene-2-5-dicarboxylate, 5 diethyl 2-(hydroxymethyl)-2,3-dihydrothieno[3,4-b][l,4]dioxin-5,7-dicarboxyl-ate, 6 diethyl 2-(hydroxymethyl)-2,3-dihydrothieno[3,4-b][l,4]dioxin-5,7-dicarbo-xylic acid, 7 2,3-dihydrothieno[3,4-b][l,4]dioxin-2-yl methanol, 8 sulfonated 3,4-ethylenedioxythiophene. (Reprinted from journal of Electroanalytical Chemistry, 443, O. Stephan, P. Schottland, P. Y. Le Gall, C. Chevrot, C. Mariet, M. J. Carrier, 217. Copyright (1998), with permission from Elsevier.)...

Figure 4.16 Synthesis of sulfonated monomer and polymer. Reagents and conditions 1, BuLi, Et20, —73°C, then allyl bromide, 2h, —73 C- ii NaHSOs azoisobutyronitrile in MeOH/HiO, 5 h, 80 C iii, FeCb in H2O, r om temp. IV, NaOH, then ion exchange resin. [Chemical Communications 1990 1694, Y. Ikenoue, Y. Saida, M. Kira, H. Tomozawa, H. Yashima, M. Kobayashi. Reproduced by permission of The Royal Society of Chemistry.)...

Reynolds et al. [54] reported the electrochemical synthesis of self-doped, water-soluble, N-propanesulfonated poly(3,4-propylenedioxypy-rrole). The sulfonated monomer, N-propanesulfonate-substituted 3,4-propylenedioxypyrrole (N-PrS PProDOP) was prepared by treating 3,4-propylenedioxypyrrole with NaH in dry tetrahydrofuran and 1-propanesulfonate as shown in Figure 5.10. The poly(N-PrS PProDOP) films were synthesized in a mixture of propylene carbonate and water (94 6) with supporting electrolyte LiC104 in the potential range —0.4 to... 

These data show that 2-propenamide and sodium 2,2-dimethyl-3-imino-4-oxohex-5-ene-1-sulfonate form a random copolymer which 1. gives a larger hydrodynamic radius in aqueous solution with increasing value of ln[M][l] " /, 2. has a maximum hydrodynamic radius in aqueous solution when the sulfonated monomer is approximately 12 mole percent of the monomer charge for synthesis, and 3. loses 31 percent of number average molecular weight as mole percent sulfonated monomer in the reaction changes from 0 to 100 mole percent. 

The S-PEEK direct synthesis from sulfonated monomer seems to be more advantageous than the post-sulfonation because it avoids the cross-linking formation and other side... 

If the S-PEEK is synthesized via two steps, monomer synthesis and polymer preparation, the DS indicates the ratio between the sulfonate monomer group number and the repeating unit in the PEEK polymer chain and it can overcome 100% [10]. In Figure 5, the formation of S-PEEKs by means of the nucleophilic aromatic substitution reaction is shown. The first step... 

Figure 2.8. The formation of a styrene-acetylene diblock copolymer and random copolymers of acetylene and phenyl vinyl sulfone using the anionic precursor method. The synthesis of the phenyl vinyl sulfoxide and phenyl vinyl sulfone monomers is also shown.

Synthesis and Emulsion Copolymerizations of Styrene Sulfonate Monomers for Cross-Linked Polyampholyte Latexes... 

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