Styrene supports

Kinetic studies of the addition of hydrogen chloride to styrene support the conclusion that an ion-pair mechanism operates because aromatic conjugation is involved. The reaction is first-order in hydrogen chloride, indicating that only one molecule of hydrogen chloride participates in the rate-determining step. ... 

Zheng, X. Jones, C. W. Week, M. (2006) Poly(styrene)-supported Co-salen eomplexes as effieient recyclable catalysts for the hydrolytic kinetic resolution of epiehlorohydrin, Chem. Eur. J., 12 576 - 583. 

Monomers Initiator Porogens Styrene Supports Application References... 

Figure 4 Kinetic plot of the ffKR of rac-epichlorohydrin using the homogeneous and poly(styrene) supported Co(III) salen catalysts.

Poly (norbornene)-supported Co(III)-Salen complexes (44) and poly (styrene)-supported Co(III)-Salen complexes (45,46) were synthesized via newly developed procedures. In particular, a new, high-yielding, one-pot synthesis of non-symmetrical salens was developed (46). Hydrolytic kinetic resolutions were carried out at room temperature and the products were characterized by chiral GC. 

In another approach, reactive monodisperse porous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads have been employed for the preparation of chiral HPLC packings. Thus, reactive chloromethyl groups were derivatized to yield amino functionalized beads onto which both rt-basic and rt-acidic type chiral. selectors, (/ )- -(l-naphthyl)ethylamine and (/ )-A -(3.5-dinitrobenzoyl)phenylglycine, respectively, were attached. The resulting chiral particles were chromatographically tested for the enantioseparation of model SAs. Despite the presence of strongly competitive it-TT-binding sites of the styrenic support these chirally modified beads afforded baseline separations for 2,2,2-trifluoro-l-(9-anthryl) ethanol and Af-(3.5-dinitro-benzoyl) leucine enantiomers, respectively [369. ... 

Heck reactions were similarly evaluated towards the same parameters dependence. As such, a library of supported stilbenes has been prepared using a styrene supported on a trimethylammonium tetrafluoroborate in association with a mixture of seven... 

Table 3.7 Preparation of substituted aza-heterocycles catalysed by poly-styrene-supported-TBD (l,5,7-triazabicyclo[4.4.0]dec-5-ene).

A Ajayaghosh, VNR Filial. Solid-phase synthesis and C-terminal amidation of peptides using a photolabile o-nitrobenzhydrylaminopoly styrene support. Tetrahedron Lett 36 777-780, 1995. 

The Kubota MBR uses a flat-sheet manbrane made of polyolefin with a nonwoven cloth base. Each m brane cartridge consists of solid acrylonitrile butadiene styrene support plate with a spacer layer between it and a flat-sheet membrane on both sides. Permeate is drawn through the membrane from the bulk fluid by a partial vacuum applied within the membrane plate matrix while retaining the solids... 

With triethylbenzylammonium bromide (TEBA) as the catalyst on a macro-porous styrene support cross-linked with 12% of divinylbenzene, the following kinetic rate constants k have been obtained (Table 6). It is noteworthy to observe that the apparatus FB-UM gives a rate constant very close to that of the SR-UM with the advantage of avoiding pulverization of the catalyst. Therefore, the FB-UM apparatus can be proposed for any reaction using a solid catalyst and an ultrasonic source to increase the reactivity with respect to silent conditions. ... 

Preparation. The PS-TsA (eq 1) is prepared in one step from poly styrene-supported benzenesulfonyl chloride (100-200 mesh, 1.5-2.0 mmol/g). Typically, 1.5 mmol of resin is swollen in DMF and then treated with 3.0 mmol of NaNs dissolved in H2O (1.0 mL) and diluted with DMF (7 mL). After 16 h the resin is washed with H2O (5x5 mL), DMF (5x5 mL), and finally with CH2CI2 (3x5 mL) and dried under vacuum at 40 °C. The loading of PS-TsA was determined to be 1.0-1.5 mmol/g by combustion analysis of two different batches. The resin is stored at rt and appears to be stable over an indefinite period of time. FTIR of the resin shows a strong band for the azide functionality at 2130 cm-. ... 

In addition to their direct use, chloromethyl groups are readily modified into other functional groups. The more important functional groups that have been introduced via chloromethyl groups are shown in Table 2-2. Modification reactions may also be phase-transfer catalyzed (Frechet et al., 1979). Other functional groups may be directly introduced into the styrene support polymer by well-known reaction sequences (Table 2-3) (Patterson, 1971 Frechet and Farrall, 1977). 

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