Hydrophilic Support Research Articles

Synthesis and characterization of supported polysugar-stabilized palladium nanoparticle catalysts for enhanced hydrodechlorination of trichloroethylene

Palladium (Pd) nanoparticle catalysts were successfully synthesized within an aqueous phase using sodium carboxymethyl cellulose (CMC) as a capping ligand which offers a green alternative to conventional nanoparticle synthesis techniques. The CMC-stabilized Pd nanoparticles were subsequently dispersed within support materials using the incipient wetness impregnation technique for utilization in heterogeneous catalyst systems. The unsupported and supported (both calcined and uncalcined) Pd nanoparticle catalysts were characterized using transmission electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction, and Brunauer–Emmett–Teller surface area measurement and their catalytic activity toward the hydrodechlorination of trichloroethylene (TCE) in aqueous media was examined using homogeneous and heterogeneous catalyst systems, respectively. The unsupported Pd nanoparticles showed considerable activity toward the degradation of TCE, as demonstrated by the reaction kinetics. Although the supported Pd nanoparticle catalysts had a lower catalytic activity than the unsupported particles that were homogeneously dispersed in the aqueous solutions, the supported catalysts retained sufficient activity toward the degradation of TCE. In addition, the use of the hydrophilic Al2O3 support material induced a mass transfer resistance to TCE that affected the initial hydrodechlorination rate. This paper demonstrates that supported Pd catalysts can be applied to the heterogeneous catalytic hydrodechlorination of TCE.

Separation performance of CO2 through Supported Magnetic Ionic Liquid Membranes (SMILMs)

Ionic liquids (ILs) have reached an enormous interest as CO2 solvents due to their unique properties such as negligible vapour pressure and selectivity, making them very attractive in order to obtain stable supported liquid membranes. ILs containing magnetic metals in their anion are known as Magnetic Ionic Liquids (MILs) and they may show different behaviour in the presence of an external magnetic field.This work evaluates the preparation and use of a new class of supported liquid membranes based on Magnetic Ionic Liquids: Supported Magnetic Ionic Liquid Membranes (SMILMs) for CO2 separation/concentration. Four paramagnetic ionic liquids have been studied: [P6,6,6,14]2+[CoCl4]2−, [P6,6,6,14]+[FeCl4]−, [P6,6,6,14]2+[MnCl4]2− and [P6,6,6,14]3+[GdCl6]3; in combination with a hydrophobic or a hydrophilic PVDF porous support. An evaluation of the membrane stability was carried out and CO2, N2 and air permeabilites for stable SMILMs were experimentally determined. CO2/N2 and CO2/air selectivities were estimated and introduced in the Robeson diagram for a comparison with previous reported materials. Pure gas permeation results demonstrate that these SMILMs show much higher CO2 permeabilities when comparing with N2 and air. This selectivity may indicate a potential application of using SMILMs for the selective removal/recovery of CO2 from a gas stream and further work will perform the evaluation of an external magnetic field in the separation behaviour.

Glucosylated steroid-porphyrins as new tools for nanotechnology applications

Two glucosylated steroid-modified porphyrins, differing in the number and type of ring substitutions, were taken into consideration as versatile chiral elements with possible applications in different environments. Three distinctive features of the title compounds were investigated by optical spectroscopy methods: (i) the formation of chiral mesoscopic structures in solution; (ii) the formation of Langmuir–Blodgett films on hydrophilic substrates; (iii) the inclusion and localization in a liposome formulation. Specifically, the aggregation propensity of mono- and disubstituted porphyrin scaffolds was studied in DMSO–H2O (40/60, v/v), where J-type aggregates were detected by the broadening and bathochromic shift of the Soret absorption band. Circular Dichroism (CD) experiments highlighted the occurrence of specific stereochemical interactions during the formation of such structures. The aggregation properties of the investigated compounds were further exploited in the formation of porphyrin multilayers through Langmuir–Blodgett deposition on hydrophilic quartz supports. The properties of the porphyrin films were characterized by pressure–area compression isotherms and optical (UV-Vis, CD, fluorescence) spectroscopy. Moreover, the interaction between the synthesized porphyrins and a membrane model represented by unilamellar 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposomes was investigated. In particular, the partition between the aqueous and lipid phases, and the location of the porphyrin derivatives in the lipid bilayer were studied by fluorescence methods. The reported results demonstrate the multitask versatility of the synthesized glucosylated steroid-porphyrins, exemplified by the formation of ordered structures in very different environments: chiral mesoscopic structures in solution, densely-packed films on inorganic supports, stable inclusion complexes in liposome formulations.

Comparison of catalytic performance of supported ruthenium and rhodium for hydrogenation of 9-ethylcarbazole for hydrogen storage applications

The stepwise hydrogenation of 9-ethylcarbazole to 9-ethyl-perhydrocarbazole (Pl 12[H]) via partially hydrogenated intermediate(s) was studied over a number of supported ruthenium and rhodium catalysts. The reaction pathways were modelled and the rate constants for individual hydrogenation steps were compared. It was found that the selectivities to the reaction intermediates and products were highly dependent on the electronic structure of the particular metal and the nature of the support used. Ruthenium was found to be the most active metal for this reaction but it suffered from a poor selectivity to the desired product due to the formation of a kinetically stable intermediate, 9-ethyl-octahydrocarbazole (Pl 8[H]) in short reaction time. On the other hand, rhodium catalysts with moderate activity gave a higher selectivity to the fully hydrogenated product under comparable conditions. It was also found that the presence of a hydrophilic support such as alumina or rutile can give kinetically favoured cis-isomers of the 9-ethyl-perhydrocarbazole. Regarding application of the reversible hydrogen storage concept, the storage material should be able to switch between fully hydrogen loaded and unloaded forms during hydrogenation (material regeneration) and dehydrogenation (delivery of hydrogen gas) in short times. Formation of any stable intermediates and stereo-non-favoured isomers with a particular type of catalyst can result in significant implications to the overall storage capacity as well as operation times for hydrogen gas delivery and regeneration. Thus, this study yields valuable information on the suitability of various metal catalysts for use in hydrogen storage systems based on the liquid organic hydride (LOH) concept.

Production of n-butanol from biodiesel derived crude glycerol using Clostridium pasteurianum immobilized on Amberlite

This paper presents accounts of research on conversion of biodiesel derived crude glycerol to n-butanol via anaerobic fermentation pathway, using immobilized Clostridium pasteurianum cells. Experiments were done to optimize the growth conditions and growth medium, viz. Reinforced Clostridial Media (RCM) and Cooked Meat Media (CMM). Out of these two media, growth was found to be faster in RCM, which was used for experiments. The cells were immobilized on a hydrophilic support Amberlite, an ion exchange resin. Varying concentration of crude glycerol as a substrate was found to have significant effect on product profile with 25gL−1 glycerol giving maximum yield of n-butanol after 120h. High concentration of 150gL−1 glycerol exerted an inhibitory effect on n-butanol production with decreased 1,3-propanediol production, and absolutely no formation of ethanol. Maximum yield of ethanol and 1,3-propanediol was obtained with 5gL−1 and 10gL−1 crude glycerol respectively. To the best of our knowledge, this is the first report of use of the immobilized cells (immobilization of C. pasteurianum cells on Amberlite) for bioconversion of glycerol to butanol.

Functionalized Lipid Nanoparticles–Cellophane Hybrid Films for Molecular Delivery: Preparation, Physicochemical Characterization, and Stability

Lipid nanoparticles functionalized with the sunscreen 2,4‐dihydroxybenzophenone (FLNPs) have been prepared by the ultrasound method and embedded in highly hydrophilic cellophane supports (regenerated cellulose, RC), creating biocompatible hybrid films (RC‐FLNPs samples). The morphology of the FLNPs was studied with transmission microscopy, whereas the surface and interior chemical composition was analyzed by micro‐Raman spectroscopy. RC‐FLNPs hybrid films were prepared from the immersion of two cellophane supports with different thicknesses and water uptake properties (RC‐3 and RC‐6) in an aqueous dispersion of FLNPs. The structure of this hybrid material was visualized with bright‐field microscopy, which clearly showed the inclusion of the FLNPs in the cellophane matrix. The stability of the RC‐FLNPs films with respect to both aqueous environments and time was demonstrated by NaCl diffusion measurements. The reduction in the diffusion coefficient through the nanoparticle‐modified films compared with the original supports confirms the presence of nanoparticles for concentration gradients of up to 0.4M (osmotic pressure around 10 bar), indicating the stability of the hybrid hydrophilic material, even in aqueous environments and under matter flow conditions for a period of 21 days. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:4815–4822, 2011

Suzuki Coupling Reactions in Pure Water Catalyzed by Supported Palladium – Relevance of the Surface Polarity of the Support

AbstractHeterogeneous (supported) palladium catalysts like palladium on carbon and a variety of metal oxides have been shown to be highly active for Suzuki coupling reactions in neat water under mild reaction conditions (T=65 °C). It has been demonstrated for the first time that hydrophobic effects of the catalyst surface play an important role for the catalyst activity in water. Catalysts possessing hydrophobic surfaces (e.g., palladium on carbon) show higher activity for Suzuki coupling reactions in water than their hydrophilic counterparts (palladium on metal oxides). Tuning of the surface polarity of metal oxide supports (by silylation) results in higher activity under these conditions. Stronger alkaline conditions (three‐fold excess of base) compensate the effect of hydrophobic supports and result in high activity of the catalysts also with hydrophilic supports. The addition of tetrabutylammonium bromide to generate, activate and stabilize the catalytic species (dissolved palladium complexes) is necessary for the conversion of more demanding substrates. The reaction is considered to be homogeneous taking place near the catalyst surface inside a droplet or layer of the reactant.

Polymer-Supported Organotin Reagent for Prosthetic Group Labeling of Biological Macromolecules with Radioiodine

In this study, we investigated the use of poly-mer-bound precursor for generating a radiolabeled prosthetic group to be used for conjugate labeling of biological macromolecules. For the approach, a trialkyltin chloride in which the tin was bound to a hydrophilic PEG-based resin support via one of the alkyl groups was synthesized. This resin was then used to prepare a resin-bound trialkyltin benzoic acid, which in some cases was further derivatized on-resin by converting it to a succinimidyl ester. Exposure of the resin-bound compounds to electrophilic radioiodine (¹²⁵I) in either an aqueous or methanol solvent liberated either free radiolabeled [¹²⁵I]iodobenzoic acid or its succinimidyl ester without co-release of the resin-bound precursors. Radiochemical yield was between 35% and 75%, depending on the solvent system and precursor. As example applications for the released compounds, the amine-reactive N-succinimidyl-[¹²⁵I]iodobenzoate prosthetic group was used for conjugate radiolabeling of a peptide, tomato plant systemin, and two proteins, albumin and IgG antibody. These results demonstrate that resin-bound organotin precursors in which the compound to be labeled is tethered to the support via the tin group to be substituted can be used to produce radioiodine-labeled aromatic prosthetic groups in good specific activity without the need for HPLC purification. This solid-phase approach is potentially adaptable to kit-formulation for performing conjugate radiolabeling of biological macromolecules.

Planar Block Copolymer Membranes by Vesicle Spreading

An easy route to planar solid-supported polymer membranes by vesicle spreading is described. Pre-organized poly(butadiene)-block-poly(ethylene oxide)(PB-PEO) assemblies were spread on two different supports, i.e. strongly hydrophilic glass surfaces and ultrasmooth gold substrates. Polymer membranes were produced on a hydrophilic support by spreading hydroxyl-functionalized polymer vesicles, while covalently immobilized polymer membranes were obtained by spreading LA-functionalized polymer vesicles on gold substrates. Covalently bound membranes were further incubated with the peptide polymyxin B. Interactions with the polymer membrane were detected by EIS. These systems are of great interest to fundamental membrane science and have potential in technological applications, such as drug screening and (bio)sensing.

Biomimetic Membranes with Aqueous Nano Chanels but without Proteins: Impedance of Impregnated Cellulose Ester Filters

Earlier we have shown that many important properties of ionic aqueous channels in biological membranes can be imitated using simple biomimetic membranes. These membranes are composed of mixed cellulose ester-based filters, impregnated with isopropyl myristate or other esters of fatty acids, and can be used for high-throughput drug screening. If the membrane separates two aqueous solutions, combination of relatively hydrophilic polymer support with immobilized carboxylic groups results in the formation of thin aqueous layers covering inner surface of the pores, while the pore volume is filled by lipid-like substances. Because of these aqueous layers biomimetic membranes even without proteins have a cation/anion ion selectivity and specific (per unit of thickness) electrical properties, which are similar to typical properties of biological membranes. Here we describe frequency-dependent impedance of the isopropyl myristate-impregnated biomimetic membranes in the 4-electrode arrangement and present the results as Bode and Nyquist diagrams. When the membranes are placed in deionized water, it is possible to observe three different dispersion processes in the frequency range 0.1 Hz to 30 kHz. Only one dispersion is observed in 5 mM KH(2)PO(4) solution. It is suggested that these three dispersion features are determined by (a) conductivity in aqueous structures/channels, formed near the internal walls of the filter pores at high frequencies, (b) dielectric properties of the whole membrane at medium frequencies, determined by polymer support, aqueous layers and impregnating oil, and, finally, (c) by the processes in hydrated liquid crystal structures formed in pores by impregnating oil in contact with water at low frequencies.

Permeation of single gases through TEG liquid membranes modified by Na-Y nano-zeolite particles

In this research, a triethylene glycol (TEG)/nano-zeolite Na-Y liquid membrane was developed in order to investigate the effect of zeolite nanoparticles on separation performance of a liquid membrane. To do this, a high yield nano-zeolite Na-Y was synthesized using mid-synthesis addition method. The synthesized samples were characterized by XRD, FT-IR, and SEM (EDX) instrumental techniques. A supported liquid membrane was prepared by impregnating a porous hydrophilic PVDF support with TEG and nano-zeolite Na-Y. The permeation tests of single gas components of O 2, N 2 and CO 2 were carried out at pressure differences of 0.8 and 1.8 bar. The permeances of the single gases were found to be: CO 2 > N 2 > O 2. Our results showed that higher loading of nano-zeolite Na-Y in TEG and higher pressure differences enhanced the permeation of CO 2 in comparison with N 2 and O 2. Also, these two factors improved the selectivity of CO 2/O 2 and CO 2/N 2 separation, but did not change N 2/O 2 separation.

Using silk woven fabric as support for lipase immobilization: The effect of surface hydrophilicity/hydrophobicity on enzymatic activity and stability

Silk fibers in the form of woven fabric were used as a novel and inexpensive carrier for the immobilization of lipase from Candida sp.99–125. In this study, the activity and stability of lipases adsorbed on two silk fabrics with different hydrophilic/hydrophobic properties were compared. Hydrophobic silk fibers functionalized with methyl groups were prepared by treatment with amino-functional polydimethylsiloxane (PDMS). The lipase immobilized on PDMS-treated fiber exhibited an over 2-fold increase in both hydrolysis and esterification activity due to the interfacial activation as compared to its immobilization on a hydrophilic support (native fiber). To characterize the properties of different immobilized derivatives, the effects of pH and temperature were investigated in the hydrolysis of olive oil. The esterification behavior in organic media with variable water contents and operational stability of immobilized derivatives were also compared. The lipase immobilized on the hydrophobic fibers could maintain a constantly high activity at a water content range from 1 to 10% (v/v), while the activity of lipase immobilized on native fibers showed a clear dependence on water content in organic media and decreased rapidly at high water content (> 2%). Furthermore, lipase immobilization on the hydrophobic support exhibited a significantly improved operational stability in esterification reaction system. After 27 batches were recycled, a high esterification yield (97%) was maintained. The results in this work indicate that a hydrophobic surface of fabric fiber promotes the interfacial activation of lipase and that woven silk could be a potential material as an immobilization matrix for industrial process.

Gas permeation studies in supported ionic liquid membranes

Room Temperature Ionic Liquids (RTILs) based on the 1- n-alkyl-3-methylimidazolium cation were immobilised in polymeric membranes, in order to study the potential of using supported ionic liquid membranes (SILMs) for CO 2/N 2 and CO 2/CH 4 gas separations. Different aspects were investigated, namely: the evaluation of the SILMs stability using two membrane supports which differ in terms of their hydrophobicity; and the effect of using RTILs with cations of different alkyl chains and also with different anions, on the permeability and selectivity of pure and humidified pure gases as well as gas mixtures. H 2, O 2, N 2, CH 4 and CO 2 gas permeabilities were determined and CO 2/N 2 and CO 2/CH 4 ideal selectivities were calculated and compared with data available in the literature described by the Robeson upper bound correlation. The effect of the presence of water vapour in different gas streams of N 2, CH 4 and CO 2 was also studied. Finally, CO 2/N 2 and CO 2/CH 4 binary mixtures (50%, v/v) were prepared and the selectivity obtained was compared with the ideal selectivity. The results show that the SILMs prepared with the most hydrophobic support are more stable than those based on the hydrophilic support, and have a high affinity for CO 2 when compared with other gases. This behaviour was observed both for pure and gas mixtures, at low pressures. The high selectivity values obtained for CO 2 indicate that these SILMs may be considered for CO 2 separation processes.

Improved enzymatic activity of Thermomyces lanuginosus lipase immobilized in a hydrophobic particulate mesoporous carrier

Lipase from Thermomyces lanuginosus has been immobilized within particulate mesoporous silica carriers, with either hydrophilic or hydrophobic supporting surfaces, produced by the newly developed emulsion and solvent evaporation (ESE) method. The Michaelis–Menten model was used to calculate the parameters related to the enzymatic activity of lipase i.e. the turnover number, k cat , and the specific activity. The specific activity was improved by immobilization of lipase onto the hydrophobic support, compared to lipase immobilized onto the hydrophilic support and lipase free in solution. The enhanced enzymatic activity of lipase onto a hydrophobic support was attributed to interfacial activation of the Thermomyces lanuginosus lipase when it is attached to a hydrophobic surface and a reduced denaturation. Confocal scanning laser microscopy (CLSM) studies, of fluorescently tagged lipase, showed that leakage of the lipase from the mesoporous particles was limited to an initial period of only a few hours. Both the rate and the amount of lipase leached were reduced when the lipase was immobilized onto the hydrophobic support.

Counter diffusion self assembly synthesis of ordered mesoporous silica membranes in straight pore supports

Ordered mesoporous silica membranes in macroporous supports were synthesized by a novel acid catalyzed counter diffusion self assembly method. Mesoporous silica was grown in the pores of the support using tetrabutylorthosilicate and cetyltrimethylammonium bromide as the silica source and surfactant, respectively. The supports used were straight pore, track-etch polycarbonate membranes. Hydrophobic supports with a pore diameter of 5 μm and hydrophilic supports with a pore diameter of 8 μm were used. The grown silica plugs had a highly ordered structure as seen by XRD and TEM studies, with a high surface area of around 990 m 2/g and a pore diameter of 2.7 nm. SEM studies and oxygen permeation experiments at constant transmembrane pressure were conducted to assess membrane quality. There was a two order magnitude decrease in the permeance after counter diffusion self assembly growth, showing that good quality membranes were synthesized. The use of hydrophobic supports, support placement and evaporation controlled self assembly are the key factors for the successful formation of these membranes by the CDSA approach.

The Preparation and Enzyme Immobilization of Hydrophobic Polysiloxane Supports

Enzymes are versatile biocatalysts and find increasing applications in many areas. The major advantages of using enzymes in biocatalytic transformations are their chemo-, regio-, and stereospecificity, as well as the mild reaction conditions that can be used. However, even when an enzyme is identified as being useful for a given reaction, its application is often hampered by its lack of long-term stability under process conditions, and also by difficulties in recovery and recycling. For ease of application and stabilization purposes, enzymes are often immobilized on solid supports. Among support matrices, hydrophobic biomaterials have been extensively used as supports for enzyme immobilization because the hydrophobic interactions not only can effectively increase the amount of enzyme immobilization, but also exhibit higher activity and retention of activity compared with hydrophilic supports. On the other hand, polysiloxane can evidently increase the amount of enzyme immobilization because of its hydrophobicity and strong affinity with enzyme. Therefore, this research details the first preparation and use of a hydrophobic polysiloxane support for enzyme immobilization in which the structural and functional characteristics of new supports have been investigated by using glucose oxidase (GOD) and a simple Fenton's assay method, and extremely interesting features were revealed. The results showed that the amount of GOD immobilization and the stability of GOD loaded, which are fundamental properties for enzyme separation and purification, can be significantly improved by adsorption. Moreover, the results indicated that hydrophobic polysiloxane supports can effectively increase the enzymatic affinity and durability of GOD, and decrease the rate of GOD desorbed.

Impacts of support membrane structure and chemistry on polyamide–polysulfone interfacial composite membranes

Herein, we discuss the properties of polyamide thin films formed via identical interfacial polymerization conditions over porous polysulfone supports with different physical and chemical properties. Polysulfone supports were formed by nonsolvent induced phase separation (i.e., immersion precipitation) employing several casting solution and precipitation bath chemistries. Hand-cast polysulfone films (and a commercial polysulfone membrane) exhibited a wide range of pure water permeabilities, dextran rejections, water contact angles, and surface roughness statistics. These results, combined with FTIR spectra and SEM images, confirm that each support offered a different skin layer pore morphology and chemistry. Polyamide composite membranes formed thereon displayed widely varying film morphology, separation performance, and interfacial properties. More permeable, hydrophilic supports produced low permeability polyamide–polysulfone interfacial composite membranes, whereas highly porous, relatively hydrophobic supports produced more permeable composite membranes. A conceptual model was proposed to explain the potential impacts of polysulfone support membrane properties during the polyamide interfacial polymerization reaction and the resulting characteristics of polyamide–polysulfone interfacial composite membranes.

Development of an epoxy-based monolith used for the affinity capturing of Eschericha coli bacteria

An epoxy-based monolith has been developed for use as hydrophilic support in bioseparation. This monolith is produced by self-polymerization of polyglycerol-3-glycidyl ether in organic solvents as porogens at room temperature within 1 h. One receives a highly cross-linked structure that provides useful mechanical properties. The porosity and pore diameter can be controlled by varying the composition of the porogen. In this work, an epoxy-based monolith with a high porosity (79%) and large pore size (22 μm) is prepared and used in affinity capturing of bacterial cells. These features allow the passage of bacterial cells through the column. As affinity ligand polymyxin B is used, which allows the binding of gram-negative bacteria. The efficiency of the monolithic affinity column is studied with Escherichia coli spiked in water. Bacterial cells are concentrated on the column at pH 4 and eluted with a recovery of 97 ± 3% in 200 μL by changing the pH value without impairing viability of bacteria. The dynamic capacity for the monolithic column is nearly independent of the flow rate (4 × 10 9 cells/column). Thereby, it is possible to separate and enrich gram-negative bacterial cells, such as E. coli, with high flow rates (10 mL/min) and low back pressure (<1 bar) in a volume as low as 200 μL compatible for real-time polymerase chain reaction, microarray formats, and biosensors.

An Effective Way To Hydrophilize Gigaporous Polystyrene Microspheres as Rapid Chromatographic Separation Media for Proteins

To overcome the disadvantages of protein denaturation and nonspecific adsorption on poly(styrene-divinylbenzene) (PS) medium as a chromatographic support, gigaporous PS microspheres prepared in our previous study were coated with hydrophobically modified agarose (phenoxyl agarose, Agap). Both the modification of agarose and the gigaporous structure of PS microspheres provided an advantage that facilitated the coating of Agap onto PS microspheres. The amount of Agap adsorbed onto the PS surface was examined as a function of the polymer concentration, and various samples of microspheres, differing in surface Agap density, were prepared. The adsorbed layer was then stabilized by chemical cross-linking and its stability was evaluated in the presence of sodium dodecyl sulfate. Results showed that PS microspheres were successfully coated with Agap, while the gigaporous structure could be well maintained. After coating, the nonspecific adsorption of proteins on PS microspheres was greatly reduced. Flow hydrodynamics experiments showed that the Agap-co-PS column had low backpressure, good permeability, and mechanical stability. Such a procedure could provide a hydrophilic low-pressure liquid chromatographic support for different types of chromatography, since the Agap layer may be easily derivatized by classical methods, and because of their good permeability, the coated microspheres have great potential applications in high-speed protein chromatography.

Solid-phase synthesis of asymmetrically substituted "AB3-type" phthalocyanines.

Synthesis of phthalocyanines with asymmetrical substitution on the periphery is often difficult due the problems in purification of the phthalocyanine mixtures obtained. Using a poly(ethylene glycol) (PEG)-based support with a Wang-type linker, we have developed the synthesis of monohydroxylated, oligoethylene glycol substituted phthalocyanines utilizing an amidine-base-promoted phthalonitrile tetramerization reaction. The use of a hydrophilic support allows symmetrical phthalocyanine product formed in solution to be readily and completely removed by washing while leaving the "AB3" product on the support. Acid cleavage with 10% trifluoroacetic acid provides the pure unsymmetrically substituted Pc. This method was applied to several metallo Pcs. Additionally, methods to avoid premature reactions on-resin that give A2B2 products are provided.