Toluene porogen

A multi-microsensor array of potentiometric MIP chemosensors has been devised for determination of a serotonin neurotransmitter [180]. In the toluene porogenic solvent solution, the MAA functional monomer and the EGDMA cross-linker were polymerized in the presence of the serotonin hydrochloride template (Table 6). Subsequently, the resulting MIPs were immobilized on a plasma polymer layer by swelling and polymerization. Plasma polymerization was performed using styrene or ethylbenzene as the monomer. The chemosensor fabricated that way was appreciably responsive to serotonin while selectivity to serotonin analogues, like acetaminophen... 

Monodispersed poly (methyl methacrylate-ethyleneglycol dimethacrylate) is prepared by a multistep swelling and polymerization method. When a good solvent such as toluene is applied as a porogen, the seed polymer severely affects the pore structure, whereas no effects are observed with poor solvents, such as cyclohexanol, as a porogen, in comparison with the conventional suspension polymerization (68,69). 

Figure 2. Representative optical micrographs of poly-HEMA cross-linked with EDMA. (a) and (b) represent the gel-type polymer produced by suspension co-polymerization in the dry and swollen state, respectively, (c) and (d) represent the macroreticular polymer produced by suspension co-polymerization in the presence of a porogen (toluene), in the dry and swollen (vide infra) state, respeetively [13], (Reprinted from Ref [15], 1996, with permission from Elsevier.)...

Fig. 13 Chromatograms of the online extraction of a human plasma sample spiked with bupivacaine and ropivacaine at 75 pmol 1. 1 and ethycaine at 40 pmol L on the MIP and the reference polymer REF, both prepared using toluene as the porogen [52]...

Horvath s group has recently reported the preparation of porous rigid monolithic capillary columns for CEC by polymerizing mixtures of chloromethylstyrene 21, divinylbenzene 22 and azobisisobutyronitrile in the presence of various porogenic solvents such as methanol, ethanol, propanol, toluene, and formamide [49]. The capillary wall was silanized using a 50% dimethylformamide solution of 3-(trimethoxysilyl)propyl methacrylate 8 at a temperature of 120°C for 6 hours. In order to avoid the spontaneous polymerization of the functional methacrylate, a stable free radical (DPPH) was added to the solution. The SEM micrographs of Fig. 6.16... 

Cross-linked polystyrene porous particles (with 21 mol% DVB) have been prepared by the concentrated emulsion polymerization method, using either toluene or decane as the porogen and an aqueous solution of SDS as the continuous phase. Since toluene is a good solvent for polystyrene while decane is a nonsolvent , the morphologies obtained in the two cases were different. The particles based on toluene (with a volume fraction of dispersed phase of 78%) have very small pores which could not be detected in the SEM pictures. The pore size distribution, which has sizes between 20 and 50 A and was determined with an adsorption analyzer, almost coincides with that in a previous study [49] in which porous polystyrene beads have been prepared by suspension polymerization. In contrast, the porous particles based on decane have pore sizes as large as 0.1-0.3 pm, which could be detected in the SEM pictures [44a], and also larger surface areas (47 m2 g ) than those based on toluene (25 m2 g ). The main difference between the concentrated emulsion polymerization and the suspension polymerization consists of the much smaller volume fraction of continuous phase used in the former procedure. The gel-like emulsion that constitutes the precursor in the former case contains polyhedral cells separated by thin films of continuous phase. The polymerization of the cells does not... 

Template porogen toluene/ benzene ethylbenzene/ toluene... 

Fig. 12.3. Electron micrographs of imprinted beads produced by suspension polymerisation of typical EDMA/MAA imprinting mixtures in a liquid fluorocarbon. The porogenic solvents were (a) toluene, (b) chloroform and (c) acetonitrile.

In a slightly modified approach, the MIPs can be rendered super-porous by the use of 1-25% iso-octane as a porogenic agent [40,41]. The porogen is composed of a mixture of solvents in which the porogenic agent (iso-octane) acts as a bad solvent for the growing polymer chains, while the other solvent (toluene for... 

Low-weight organic molecules, such as volatile organic compounds (VOCs) [25], e.g. hydrocarbons without functionalities or anaesthetics, can be used as print molecules for non-covalent MIPs. If the print molecule is a suitable organic solvent, the print molecule itself is the porogen during the polymerisation process. Enhanced imprinting effects are promoted by n-n interactions between aromatic moieties in monomers and analytes, such as polycyclic aromatic hydrocarbons (PAHs) or aromatic VOCs (xylene or toluene, for example). 

Luis prepared polymeric monoliths 17 containing TADDOL subunits [13] these were synthesized with a thermally induced radical soluhon polymerization of a mixture containing TADDOL monomer, styrene and DVB, using toluene/1-dodecanol as the precipitating porogenic mixture and azoisobutyronitrile (AIBN) as the radical inilialor. The polymer-supported Ti-TADDOLates generated from 17 and Ti(OiPr)4 were then used for the asymmetric alkylation of benzaldehyde to give 1-phenylethanol in 60% yield and 99% ee [13]. 

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