Polymer immobilised

Polymer-immobilised catalysts containing gold particles smaller than 10 nm have been prepared by impregnating Merck Ion Exchanger IV with HAuCU, and have been used to synthesise ureas and carbamates by reaction of amines with carbon monoxide and oxygen 16 so for example the oxycarbonylation of aniline proceeded at 448 K and 5 MPa pressure (C0 02 = 2 l) in 1-3 h to give yields of up to 99% of phenylmethyl-carbamate (Scheme 13.3). 

POLYMER IMMOBILISED TEMPO (PIPO) AN EFFICIENT CATALYTIC SYSTEM FOR ENVIRONMENTALLY BENIGN OXIDATION OF ALCOHOLS... 

Here we report the use of a readily prepared polymer immobilised TEMPO as a catalyst for alcohol oxidations.15 It was derived from a commercially available oligomeric, sterically hindered amine, poly[[6-[(l,l,3,3-tetramethylbutyl)amino]-l,3,5-triazine-2,4-diyl] [2,2,6,6-teramethyl-4-piperidinyl)-imino]-1,6-hexane-diyl[(2,2,6,6-tetramethyl-4-piperidinylimino]], better known as Chimassorb 944 (MW 3000 see figure 3 for structure). This compound is used as an antioxidant and a light stabiliser for plastics. It contributes significantly to the long-term heat stability of polyolefins and has broad approval for use in polyolefin food packaging.16... 

Polymer Immobilised TEMPO An Efficient Catalytic System for Oxidation of Alcohols... 

Polymer Immobilised TEMPO (PIPO) An Efficient Catalytic System for Environmentally Benign Oxidation of Alcohols 118... 

The equilibration of one of the Eu complexes having a labile cation with a solution containing a small amount of a different cation, so as to bring about cation exchange, was performed. The methodology involved the use of a filter paper substrate to simulate a polymer immobilised reagent. The first experiments... 

The polymer-immobilised nanogold is also an effective catalyst for carbonylation of amines with CO2 to yield corresponding disubstituted ureas... 

Scheme 2.32 Synthesis of syn -amide alcohol with polymer-immobilised ruthenium catalyst.

Foulds, N. C. Lowe, C. R. Enzyme entrapment in electrically conducting polymers. Immobilisation of glucose oxidase in polypyrrole and its apphcation in amperometric glucose sensors. J. Chem. Soc., Faraday Trans. 1 1986, 4, 1259-1264. 

PomogaUo Anatohi D. Polymer-immobilised clusters of the platinum group metals. Platin. Met. Rev. 38 no. 2 (1994) 60-70. 

In addition, several supported chiral ionic liquids have been investigated for these reactions. Therefore, Wang et al. have developed a new type of polymer-immobilised pyrrolidine-based chiral ionic liquids, which were capable of inducing the Michael addition of ketones to nitrostyrenes in high yields. 

Polyazetidine prepolymer may be cross-linked in aqueous solution by reaction with amine, thiol, hydroxyl, carboxylic add or other polyazetidine groups. Cross-linking occurs upon water removal, heating or by changing to a basic pH. The immobilised cell/polymer composition may be prepared in the form of membranes, fibres, tubes or beads. 

Recommended model particle systems are enzymes immobilised on carriers ([27,44,45,47,49]), oil/water/surfactant or solvent/water/surfactant emulsions ([27, 44, 45] or [71, 72]) and a certain clay/polymer floccular system ([27, 42-52]), which have proved suitable in numerous tests. The enzyme resin described in [27,44,47] (acylase immobilised on an ion-exchanger) is used on an industrial scale for the cleavage of Penicillin G and is therefore also a biological material system. In Table 3 are given some data to model particle systems. 

Since catalysts immobilised on hydrophilic silica gel often give superior performances to their polymer-bound or polymer-incorporated analogues for multiple applications, Heckel and Seebach have immobilised TADDOL derivatives on hydrophobic controlled-pore glass (CPG) silica gel. Indeed, CPG is... 

It has been observed that complete immobilisation of the stabiliser through a graft leads to deactivation. However, proper selection of the ratio of phenolic to graftable groups leads to a polymer-bound product which retains sufficient mobility to provide a high level of antioxidant activity. An n/m ratio of 5-10 provides an optimal balance of graftability and antioxidant activity [144]. 

For trace analysis in fluids, some Raman sensors (try to) make use of the SERS effect to increase their sensitivity. While the basic sensor layout for SERS sensors is similar to non-enhanced Raman sensors, somehow the metal particles have to be added. Other than in the laboratory, where the necessary metal particles can be added as colloidal solution to the sample, for sensor applications the particles must be suitably immobilised. In most cases, this is achieved by depositing the metal particles onto the surfaces of the excitation waveguide or the interface window and covering them with a suitable protection layer. The additional layer is required as otherwise washout effects or chemical reactions between e.g. sulphur-compounds and the particles reduce the enhancement effect. Alternatively, it is also possible to disperse the metal particles in the layer material before coating and apply them in one step with the coating. Suitable protection or matrix materials for SERS substrates could be e.g. sol-gel layers or polymer coatings. In either... 

Positively or negatively charged indicators can be made lipophilic by ionpairing with surfactants. However, they can also be directly immobilised on the polymer by ion-pairing with ionic polymers (polyelectrolytes) (Table 9). Solutions or suspensions of the polymer are then mixed with aqueous or alcoholic solutions of the dye. 

Sensors for acidic (HC1, SO2, CO2, acetic acid) or basic gases (NH3, amines) often make use of pH indicator dyes immobilised in polymers. Lipophilic Bromophenol Blue (see section 4.2) dissolved in silicone is... 

Recently, the immobilisation of indicators in tiny beads rather than in polymer layers has provided nanoparticles which can be inserted into cells and allow the measurement of various analytes (oxygen, sodium, potassium) within a living cell16. 

Construction of the optode for urea biosensor requires immobilisation of protein (and pH indicator) in the host matrix. There are several methods enabling protein entrapment. One can use gels, polymers, saccharose, various meshes and membranes78. 

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