Sulphone Modified Polymer

A two-step method for the combinatorial synthesis of amines and amino alcohols using vinylsulfomethylpolystyrene is described. This solid-phase synthetic route requires very few reagents for the permutational synthesis of new heterocyclic amine derivatives. 

A slurry of the Merrifield resin (2.9 mmol) in 20 ml of dry DMF was treated with 2-hydroxy-ethanethiol (15.25 mmol), K2CO3 (14.5 mmol), and pyridine(12.9 mmol), and the suspension was stirred for 4 hours at 95°C. It was then left stirring overnight at 20°C. The resin was filtered and washed extensively with DMF, CH2CI2, water, water/ methanol, 1 1, and methanol. The material was dried under vacuum at 50°C and 3.92 g of product were isolated. 

The Step 1 product (0.7 mmol) in CH2CI2 was treated with 3-chloroperbenzoic acid (5.2 mmol) and the suspension was heated at 35°C for a brief period and then stirred at 20°C for 2 days. After filtration the resin was washed with DMF, CH2CI2, water, water/ methanol, 1 1, and finally methanol. After drying at 50°C under vacuum, 1.51 g of product was isolated. 

The Step 2 product (0.65 mmol) suspended in 25 ml of dry CH2CI2 was treated with PBr3 (2.28 mmol) at ambient temperature for 12 hours and then filtered, washed with 200 ml of CH2CI2, and air dried, and the product was isolated. 

The Step 3 product was mixed with 20 ml of DMF, and tetrahydroquinoline (5.7 mmol) was added. The mixture was stirred at ambient temperature for 24 hours. After filtering, the material was washed with DMF, methanol, CH2CI2, and methanol and then dried. This material (0.5 mmol) was re-suspended in 10 ml of DMF, treated with allyl bromide (150 mm) and stirred 5 days at ambient temperature. It was then filtered and washed with 100 ml apiece of DMF and CH2CI2. It was further treated with di-isopropylethyl amine (1.00 mmol) in 25 ml of CH2CI2 and stirred 2 days at ambient temperature. The solid was isolated by filtration and then washed with CH2CI2 and methanol 59% analytical pure product was isolated. 

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M 14. — D. G. Smith, W. E. Mark, and T. R. E. Kressman Solvent-modified polymer networks. I rt I. The preparation and characterisation of expanded network and macroporons st)onne-divinylbenzene copolymers and their sulphonates. J. Chem. Soc. 1963. 218. 

M 15. — — — — Solvent-modified polymer networks. Part II. Effect of structure on cation-exchange kinetics in sulphonated styrene-divinyibenzene copolymers. J. Chem. Soc.T963, 2779. 

Modification of Polymers. One way to solve the problem of finding good polymers for membranes is to make modifications of the chemical structure of the polymer. Sulphonation for instance of polysulphone (19) is a well known example of how a hydrophobic polymer can be modified to a hydrophilic polymer with charged groups. Other attemps have been made, for instance to modify cellulose acetate by putting charged positive groups in the form of quaternary ammonium into the polymer (20). 

Further studies have also appeared in the mass transfer properties of the modifying layers. The mass transfer behavior of the polymer [Os(bipy)2(PVP)ioCl]Cl in para-toluene sulphonic acid has been studied in de-tail. In this study the effect of the non-rigidity of the layer on the mass transport data is discussed in some detail. A detailed study of the pH dependence of the mass transfer of a glassy carbon electrode modified with the [Ru(bipy)2(PVP)io(H20)] is reported. This study shows that the EQCM can be used very effectively for the study of redox reactions which show complicated (in this case pH dependent) features. (See also Section 8.2). 

The discovery of mediators (small molecules which when oxidised by peroxidases or laccases form highly reactive species), which have the abihty to oxidise high redox potential substrates difficult to be oxidised by the enzyme alone, has further expanded the applications of these enzymes in modifying inert polymers. Examples of widely investigated mediators are 1-hydroxybenzotriazole (HBT), violuric acid (VA), A-hydroxyacetanilide (NHA) and 2,2 -azinobis-(3-ethylbenzothiazoline)-6-sulphonate (ABTS). Alternatively, active research is aimed at developing natural cost-effective lignin-derived mediators [10]. 

The benzene nucleus in polystyrene undergoes normal aromatic reactions and thus the polymer may be, for example, alkylated, halogenated, nitrated and sulphonated. A frequent practical difficulty in carrying out such reactions is one of finding a reaction medium in which the polymer is soluble also, chain scission, cross-linking and discoloration often accompany these reactions. Chemically-modified polystyrenes have found little commercial application but sulphonated styrene-divinylbenzene copolymers (which are cross-linked) find use as cationic exchange resins the nature of such resins is illustrated by the following strueture ... 

The flcune retardcuicy of all epoxy systems was enhcuiced by the incorporcition of POSS nano reinforcements (Table 3.8). This might possibly be due to the formation of oxidatively stable, nonpermeable surface char and a multilayered carbonaceous sflicate structure that acted as an insulator. Besides this, the better exfohation of POSS within the polymer matrices may also have accomited for an enhanced flame retardancy to epoxy resins. The effect of POSS towards flame retardmcy wcis more in the case of phosphorous- and siloxane-modified tetrafunctional epoxy systems them the sulphone and need epoxies, thereby supporting the results obtained from mechanical, thermo-mechanical and thermal studies as discussed earher. 

The results of surface coating 10 different polymers with HE res. ES-HS can be seen in Table 1. GAG type 2 and regioselective modified heparin derivative immobilisation was achieved by amide bond formation between carboxyl groups on the polymer surface and amino groups in the GAG chain or vice versa carboxyl groups were activated by the water soluble carbodiimide N-cyclohexyl-N -(2-morpholinoethyl)carbodiimide-methyl-p-toluene sulphonate (CME-CDl). 

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