Poly supports membrane syntheses

Chapman et al. [131] reported the synthesis of poly(ethylene oxide) (PEO) supported dendritic f-BOC-poly(a, c-L-lysines). These dendritic polymers termed as hydramphiphiles formed foams possessing good temporal stability in aqueous solution. Scrimin et al. [132] synthesized a three-directional polypeptide having uses in membrane permeability modulation. Decapeptide fragments were linked to TREN [tris(2-aminoethyl)amine] core. 

All peptide-catalyzed enone epoxidations described so far were performed using insoluble, statistically polymerized materials (neat or on solid supports). One can, on the other hand, envisage (i) generation of solubilized poly-amino acids by attachment to polyethylene glycols (PEG) and (ii) selective construction of amino acid oligomers by standard peptide synthesis-linked to a solid support, to a soluble PEG, or neat as a well-defined oligopeptide. Both approaches have been used. The former affords synthetically useful and soluble catalysts with the interesting feature that the materials can be kept in membrane reactors for continuously oper-... 

Besides classical resin beads, other polymeric carriers were also used for the synthesis ofpeptide libraries in various formats. Poly aery late-grafted polypropylene pins were used for the synthesis of the first combinatorial chemical library [1,2], This type of support continues to be heavily used in multiple peptide [27] and non-peptide [28] library synthesis. Cellulose paper, originally used by Frank et al. as a solid-phase support for oligodeoxy-ribonucleotide synthesis [29], has also been used as the support for multiple SPOT synthesis of peptide libraries [30,31], Polystyrene-grafted polyethylene film (PS-PE) may also be used in combinatorial peptide library synthesis [32], The specific feature of the membrane type of carrier is its dividability. This feature has been used for the synthesis of libraries with a nonstatistical distribution of library members, where no compound is missing and none is represented more than once [33],... 

Reports are also available on CO2 selective membrane reactors for WGS reaction. Zou et al. [40] first time synthesized polymeric C02-selective membrane by incorporating fixed and mobile carriers in cross-linked poly vinyl alcohol. Micro-porous Teflon was used as support. They used Cu0/Zn0/Al203 catalyst for low temperature WGS reaction. They investigated the effect of water content on the CO2 selectivity and CO2/H2 selectivity. As the water concentration in the sweep gas increased, both CO2 permeability and CO2/H2 selectivity increased significantly. Figure 6.18 shows the influence of temperature on CO2 permeability and CO2/H2 selectivity. Both CO2 permeability and CO2/ H2 selectivity decrease with increasing reactimi temperature. After the catalyst activation, the synthesis gas feed containing 1% CO, 17% CO2, 45% H2 and 37% N2 was pumped into the membrane reactor. They are able to achieve almost 100% CO conversion. They also developed a one-dimensional non-isothermal model to simulate the simultaneous reaction and transport process and verified the model experimentally under an isothermal condition. 

Li et al. (2008a) introduced solvent-resistant multifunctional PV membranes based on segmented polymer networks (SPNs). Hydrophilic (acrylate)-terminated poly(ethylene oxide) was used as a macromolecular cross-linker of different hydro-phobic polyacrylates for the synthesis of amphiphilic SPNs. Multifunctional canposite membranes with thin SPN top layers were prepared by in situ polymerization. The support consisted of hydrolyzed PAN. These membranes were tested for dehydration of EtOH and isopropyl alcohol. The selectivity of the membranes greatly depended on the composition or the ratio of the hydrophilic and hydrophobic phases of the SPN. 

Figure 5.40 Synthesis and self-assembly of poly(2,3-dihydro)q butylene-a/t-butylene di-thioether) poly(DHB-a/t-BDT)s. (I) Synthetic pathway and functionalization. (II) Proposed self-assembly route and cross-section view of the membrane (supported by DPD calculations).

For monolithic disk synthesis, solutions of NBE, DMN-H6, and tris(norborn-5-ene-2-ylmethylenoxy)methylsilane, respectively, in 2-propanol and toluene (25 25 41 9, all wt.%) were subject to ROMP using the first-generation Gmbbs initiator RUCI2 (PCy3)2(CHPh) and triphenylphosphine (PPhs) as modulator. To come up with disks with sufficient mechanical strength, poly (amide) membranes were soaked with the polymerization mixture (Scheme 33). This way, membrane-supported monolithic disks up to 2 mm in thickness were realized. These disks were successfully used for the preconcentration of iodine and selected organic solutes from dilute aqueous samples by SPE. Quantitative measurement of the extracted solutes was achieved by diffuse-reflectance spectroscopy (DRS) directly on the surface of the disk. 

Ben et al. reported a convenient method for the synthesis of polymer-supported and large-scale free-standing MOF membranes [152]. First, a poly(methyl-methacrylate) (PMMA) was spin-coated on a template substrate, which could be any solid surface of metal or plastic. Then the PMMA surface was hydrolyzed by concentrated sulfuric acid and converted into PMAA. After that, the PMMA-PMAA coated substrate was immersed into MOF precursor solution in an autoclave for a suitable reaction time. For the further preparation of a free-standing MOF membrane, the as-synthesized MOF membrane can be separated from the substrate by dissolving the PMMA-PMAA in chloroform. Thus, an intact fi ee-standing MOF membrane with manifold size and shape, and a thickness from hundreds of nanometers to hundreds of micrometer was obtained. Ben et al. claimed that this MOF... 

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