Organic Phase Reaction Research Articles

Preparation of double-loaded bitter ginseng derivative B21–DOX liposomes co-modified with SP94 and BR2 ligand and its in vitro anti-hepatocarcinogenic effect

Aim To construct a novel liposomal drug delivery system co-modified with SP94 and BR2 ligands, encapsulating both the bitter ginseng derivative B21 and doxorubicin (DOX), to achieve superior anti-tumour efficacy and reduced toxic side effects. Methods Liposomes were prepared using an organic phase reaction method, with B21 encapsulated in the lipid phase and DOX in the aqueous phase. The liposomes were further modified with SP94 and BR2 peptides. The characterisations, cytotoxicity, and in vitro targeting effects were assessed through various methods including ultraviolet spectrophotometry, high-performance liquid chromatography, nano-size analysis, ultrafiltration centrifugation, dialysis, transmission electron microscopy, flow cytometry, Methylthiazolyldiphenyl-tetrazolium bromide assay, confocal laser scanning microscopy, transwell assay, and tumorsphere assay. Results SP94/BR2-B21/DOX-LP liposomes were spherical with an average diameter of 120.87 ± 1.00 nm, a polydispersity index (PDI) of 0.223 ± 0.006, and a surface charge of −23.1 ± 1.27 mV. The encapsulation efficiencies for B21 and DOX were greater than 85% and 97% (mg/mg), respectively. The results indicated that SP94/BR2-B21/DOX-LP exhibited enhanced targeting and cytotoxicity compared to single-ligand modified and unmodified liposomes, with the combined encapsulation of B21 and DOX showing synergistic anti-hepatocarcinogenic effects. Conclusion SP94/BR2-B21/DOX-LP liposomes represent a promising targeted drug delivery system for hepatocellular carcinoma, offering improved membrane penetration, enhanced therapeutic efficacy, and reduced systemic toxicity.

Leveraging tannic acid-ferric iron (TA/Fe3+) complexation in polyamide selective layer for synthesizing robust thin film composite reverse osmosis (TFC-RO) hollow fiber membranes for saline water treatment

The high efficiency and adaptability of reverse osmosis (RO) are two main reasons this separation technology is accepted worldwide, depending on its various uses, such as water purification, desalination, and concentration. The potential of RO can be enhanced by utilizing the hollow fiber (HF) mode, benefiting from higher packing density, ease of cleaning, and cost competitiveness. However, its suitability for RO applications becomes questionable due to its weaker and fragile mechanical resilience. To solve the abovementioned issue and improve the mechanical strength and burst/crush pressure, we propose optimizing the selective layer of the TFC-RO membrane using tannic acid complexation with FeCl3. The polyethersulfone (PES) support layer was initially fabricated to host the polyamide (PA) layer. Subsequently, the introduction of tannic acid-ferric chloride complexation was implemented as a sandwich layer between the aqueous and organic phase reactions to host a coherent and selective PA layer to further enhance its performance by controlling the kinetics of interfacial polymerization (IP). The surface morphology, physicochemical properties, and underlying reactions were analyzed using scanning electron microscopy (SEM), atomic force microscope (AFM), Fourier infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), and water contact angle measurements. The TFC-RO membrane M_TA0.2/Fe7.5 (7.5 mM FeCl3 & 0.2 wt% tannic acid) showed significant improvement in pure water permeance and salt rejection along with 7.23 MPa of burst pressure and 68.41 % strain, which proves superior elasticity and mechanical robustness because of PA TA/Fe3+ complexes formed during the IP. Moreover, the proposed facile tannic acid modification is effective and scalable. It significantly improves the mechanical efficacy of the HF TFC-RO membrane, solving a great problem for its commercial adaptability for RO applications and paving the way for smoother industrial translation for direct human factor applications.

Supramolecular immobilization of lipase inspired by octopus suckers for biodiesel production

It is still a challenge to design a supramolecular interaction system for immobilizing enzymes efficiently and stably. In this work, inspired by octopus suckers, we used cyclodextrin with a similar structure to the octopus sucker cavity as supramolecular interaction functional units of soft tentacles to immobilize lipase through physical adsorption. By modifying the surface of cyclodextrin with polar hydrophilic groups, the difference in hydrophilic and hydrophobic properties and stability within the molecule were effectively improved, thereby enhancing the cavity suction of cyclodextrin. The enzyme load of the soft tentacles reached 10 mg/g, and the lipase was adsorbed firmly under high strength mechanical action (the retention rate is 66.4%, other physical adsorption under the same conditions is 51.6%). The soft tentacle immobilized lipase showed good dispersibility in the organic phase and its water absorption characteristics could provide oil-water interface for lipase in organic phase reaction, promoting the forward transesterification reaction. Compared with free lipase, the soft tentacle immobilized lipase (L-CDST-Ms) showed the improved activity, which could reach 180% of that of free lipase. The L-CDST-Ms was applied to biodiesel production, and the conversion rate could reach 94%. The results showed that the immobilization method opened up a new way for the application of lipase in transesterification.

Fast radiation-induced reactions in organic phase of SANEX system containing CyMe4-BTPhen extracting agent

The mechanism of radiation-induced fast reactions occurring in the early stages in the 1-octanol system containing 2,9-Bis-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo (Herbst et al., 2011; Nash et al., 2015; Bourg et al., 2015)triazin-3-yl)- (Herbst et al., 2011; Panak and Geist, 2013)phenanthroline (CyMe4-BTPhen) extracting agent were studied. This is a simplified model of the r-SANEX organic phase for the selective actinide(III)/lanthanide(III) separation. Effects of various scavengers as well as water content were under consideration. Radiation chemical yield of e−s (G(e−s)) and their molar absorption coefficient (ε(e−s)) in 1-octanol were found to be 130(10) nmol J−1 and 18500(700) M−1 cm−1, respectively. Rate constants of e−s reactions with H+, O2, CyMe4-BTPhen and its protonated form were found to be 1.5(3) × 109, 1.0(1) × 1010, 1.85(9) × 109, 1.9(6) × 109 M−1 s−1, respectively. The C37 value for scavenging of dry electrons (e−dry) by CyMe4-BTPhen was equal to 30.4(8) mM. Rate constants of H• reactions with CyMe4-BTPhen and its protonated form were found to be < 7.2 × 109 and 4.3(9) × 109 M−1 s−1, respectively. A relatively good extraction performance of the system studied under exposition to high radiation doses was explained on the basis of hydroxyloctyl substitution in a phenanthroline aromatic ring.

Molecular-Scale Ligand Effects in Small Gold–Thiolate Nanoclusters

Because of the small size and large surface area of thiolate-protected Au nanoclusters (NCs), the protecting ligands are expected to play a substantial role in modulating the structure and properties, particularly in the solution phase. However, little is known on how thiolate ligands explicitly modulate the structural properties of the NCs at atomic level, eventhough this information is critical for predicting the performance of Au NCs in application settings including as a catalyst interacting with small molecules and as a sensor interacting with biomolecular systems. Here, we report a combined experimental and theoretical study, using synchrotron X-ray spectroscopy and quantum mechanics/molecular mechanics simulations, that investigates how the protecting ligands impact the structure and properties of small Au18(SR)14 NCs. Two representative ligand types, smaller aliphatic cyclohexanethiolate and larger hydrophilic glutathione, are selected, and their structures are followed experimentallyin both solid and solution phases. It was found that cyclohexanethiolate ligands are significantly perturbed by toluene solvent molecules, resulting in structural changes that cause disorder on the surface of Au18(SR)14 NCs. In particular, large surface cavities in the ligand shell are created by interactions between toluene and cyclohexanethiolate. The appearance of these small molecule-accessible sites on the NC surface demonstrates the ability of Au NCs to act as a catalyst for organic phase reactions. In contrast, glutathione ligands encapsulate the Au NC core via intermolecular interactions, minimizing structural changes caused by interactions with water molecules. The much better protection from glutathione ligands imparts a rigidified surface and ligand structure, making the NCs desirable for biomedical applications due to the high stability and also offering a structural-based explanation for the enhanced photoluminescence often reported for glutathione-protected Au NCs.

Ultrasonically Promoted Synthesis of Ethyl 2-(naphthalen-2-yloxy)acetate in Solid-Liquid Heterogeneous Phase Transfer Catalysis Condition

In this paper, the synthesis of ethyl 2-(naphthalen-2-yloxy)acetate from β-naphthol and ethyl 2-bromoacetate under ultrasound and catalyzed by quaternary ammonium salt in solid-liquid heterogeneous condition was described. Trace amount of water play a major role in this solid-liquid reaction. The reaction follows pseudo first order rate law. The apparent rate constant of the organic phase reaction was obtained form the experimental data. The combination of small amount of tetrabutylammonium bromide (TBAB) and ultrasound (kapp = 25.22×10-3 min-1) shows several fold enhanced rate of the reaction than the conventional operation (kapp = 6.42×10-3 min-1 for TBAB only). The rate constant increases (0.05 to 0.3 g) with increase in the concentration of catalyst (from kapp = 10.12×10-3 min-1 to kapp = 34.46×10-3 min-1). The other kinetic effects such as, effect of agitation speed, kind of frequency of ultrasound, kind of various quantity of K2CO3, quantity of water, temperature, different quaternary ammonium salts, solvents and volume of organic solvents on the conversion of ethyl 2-bromoacetate and apparent rate constant were investigated in detail and rational explanations are provided.

Novel kinetics model for third-liquid phase-transfer catalysis system of the “complex” carbanion: Competitive role between catalytic cycles

Kinetic model for Horner–Wadsworth–Emerson (HWE) reaction of the “complex” carbanion in the third-liquid phase-transfer catalysis (TLPTC) system was proposed and the factors that influenced the model parameters were investigated in details. The generation process and the composition of the third phase revealed that there were two catalytic cycles (the third phase reaction and the organic phase reaction) in this TLPTC system. Kinetic model which consisted of ion-exchange reaction rate constant, bond-forming reaction rate constant and the contribution ratio between each two catalytic cycle was deduced. Distribution of the carbanion ion-pair between the third phase and the organic phase caused the competitive relationship between these two catalytic cycles. Third phase was the preferred region for the bond-forming reaction, and which contribution was always 5–6 times higher than that of the organic phase reaction. Reaction rate of each catalytic cycle was also affected by lipophilicity of the anion in this TLPTC system. The steric hindrance, lipophilicity of the catalyst cation and polarity of the third phase were primary factors influencing catalyst activity.

Synthesis of 3,5-dimethyl-1-prop-2-enylpyrazole under solid–liquid phase transfer catalytic conditions assisted by ultrasonic irradiation—A kinetic study

The synthesis of 3,5-dimethyl-1-prop-2-enylpyrazole was successfully carried out by reacting the 3,5-di-methyl pyrazole with 3-bromoprop-1-ene in small amount of KOH and organic solvent solid–liquid phase medium under phase transfer catalysis (PTC) and almost anhydrous conditions assisted by the ultrasonic irradiation in the 5h at 50°C. The main target of this carried work was to provide evidence that the reaction conditions by investigation of the kinetic behaviour, activation energy, reaction mechanism and the related parameters in the solid–liquid PTC reaction besides on to reduce time and temperature of reaction. A rational mechanism for the reaction has been derived base on the experimental result. This kinetic reaction follows pseudo first order rate law. A rate expression had developed to explain the kinetic behaviours from which the apparent rate constant (kapp) of the organic-phase reaction was obtained via investigated data. Kinetics of the reaction, including the effects of agitation speed, quantity of potassium hydroxide, quantity of water, temperature, quantity of tetraoctylammonium bromide (TOAB), volume of cyclohexanone, quarternary ammonium salts and organic solvents on the conversion of RBr and the apparent rate constant (kapp) were investigated in full length. Rational explanations for the resulting phenomena are also provided.

Electrochemical oxygen reduction at soft interfaces catalyzed by the transfer of hydrated lithium cations

The oxygen reduction reaction by decamethylferrocene (DMFc), triggered by hydrophilic metallic cations behaving as Lewis acids towards water molecules in a homogeneous organic phase reaction, was investigated using cyclic voltammetry at the water|1,2-dichloroethane (w|DCE) interface. Simulated CVs, prepared through a facile 1-dimensional geometry in COMSOL Multi-physics software and incorporating interfacial and homogeneous reactions, were compared to experimental ones in order to elucidate the kinetics, thermodynamics, and viability of the proposed mechanism. The predominant O2 reduction reactions were proposed to occur in bulk organic phase, or in the vicinity of the w|DCE interface; six organic phase reactions were put forward. The first step was hydrolysis made possible through polarization of the OH bond of water molecules available in the cations hydration shell. The metal ion behaves as a Lewis acid coordinating to the oxygen and weakening the OH bond, making the proton more acidic, thereby facilitating attack by decamethylferrocene (DMFc) to form DMFc-H+. DMFc-H+ then participates in dioxygen reduction, generating the O2H radical species and DMFc+. Afterwards, the radical oxidizes another equivalent of DMFc to produce O2H−, that can then abstract a proton from the metal ions hydration sphere to generate hydrogen peroxide. The disproportionation of O2H− and the ion-pair formation of Li+ and OH− make up the other two reactions. The CV analysis was based on two curve features; the DMFc+ transfer wave and the positive limit of the polarizable potential window – the edge of scan potential profile – including the metal ion return peak. The goal of this article is to determine the kinetic/thermodynamic aspects of this mechanism from the experimental electrochemical data.

Kinetic study of dichlorocyclopropanation under phase-transfer catalysis and assisted by microwave irradiation

This work studies dichlorocyclopropanation which was performed by reacting olefins with chloroform in an alkaline solution of NaOH/organic solvent two-phase medium using phase-transfer catalysis (PTC) and microwave irradiation. The conventional quaternary ammonium salts were used as phase-transfer catalyst. A new compound 3-(N,N-dimethyloctylammonio)-propansulfonate (S-8) which was synthesized from the reaction of dimethyloctyl-amine and 1,3-propansultone, was also employed as the phase-transfer catalyst. We found that the catalyst (S-8) is more effective than those of the conventional quaternary ammonium salts in dichlorocyclopropanation. The addition was preceded via the production of dichlorocarbene from the reaction of chloroform and NaOH. The advantage of using microwave irradiation is that it increases the reaction rate and the conversion. Based on the experimental data, a rational mechanism of the interfacial reaction is proposed. The reactions follow a pseudo-first-order rate law. A rate expression was developed to describe the kinetic behavior from which the apparent rate constant (kapp) of the organic-phase reaction was obtained. The kinetics of the reaction in studying the effects of reaction conditions on the conversion of reactant and the apparent rate constant (kapp) were investigated in detail. Rational explanations of the resulting phenomena are provided.

Chemical Synthesis of Monodisperse Magnetic Nanoparticles for Sensitive Cancer Detection

This short tutorial review highlights the advance in high temperature solution phase chemical synthesis of monodisperse magnetic nanoparticles (MNPs), especially iron oxide NPs, as contrast enhancement agents for cancer detection by magnetic resonance imaging (MRI). It introduces briefly the unique nanomagnetism of MNPs required for MRI. It then summarizes some typical methods used to prepare monodisperse Fe3O4 and ferrite MFe2O4 MNPs from high temperature organic phase reaction with controlled magnetic properties. It further outlines the chemistry used to make these MNPs biocompatible and target-specific. Finally it presents two examples to demonstrate the MNP control achieved from chemical synthesis for sensitive detection of cancer.

Determination of Kinetics in Biphasic Recognition Chiral Extraction for Separation of Phenylsuccinic Acid Enantiomers

This paper reports on the determination of the intrinsic kinetics in biphasic recognition chiral extraction of phenylsuccinic acid enantiomers (H2A) by L-IBTA and HP-β-CD in a modified Lewis cell. The two-phase homogeneous reaction model was selected, because there is a finite physical solubility of phenylsuccinic acid enantiomers in both the aqueous phase and the organic phase. The regime analysis was split up in three parts: a regime analysis on the aqueous phase reaction in the absence of organic phase reaction, a regime analysis of the organic phase reaction in the absence of the aqueous phase reaction, and a regime analysis of reactions in both phases. The reactions have been found to be first order with respect to H2A and second order with respect to L-IBTA and HP-β-CD. Competitive extraction of H2A enantiomers with HP-β-CD and L-IBTA has great influence on the extraction process. With increase of HP-β-CD concentration, high enantioselectivity was obtained, but the extraction rate decreases.

A KINETIC STUDY OF PHASE TRANSFER CATALYZED BENZYLATION OF 2,4,6-TRIBROMOPHENOL IN LIQUID-LIQUID TWO-PHASE SOLUTION

Phase-transfer catalytic reactions of the derivatives of benzyl halide and 2,4,6-tribromophenol have been successfully carried out in an organic solvent/alkaline solution of KOH two-phase medium. The main purpose of this work is to study the effects of the leaving groups, orientations, and functional groups of the derivatives of benzyl halide on the reaction rate and the product yield. To identify the reaction rate in the organic phase, 2,4,6-tribromophenol is employed as the nucleophilic reagent under phase-transfer catalytic reaction. Reactions of aqueous phase and organic phase can be separately carried out to determine the reaction rate constants. Results obtained from the single organic-phase reaction are compared with those obtained from the two-phase phase transfer catalytic reaction. According to the experimental data, simplified models for representing the single-phase reaction and the two-phase reactions were proposed and derived. The reaction rate constants for the single-phase model (ks) and the two-phase model (kT) were compared to show their consistency. The kinetics of the reactions of the derivatives of benzyl halide and 2,4,6-tribromophenol were also studied. The effects of the leaving group, orientation, and functional group of the organic substrate on the reaction rate constant were also investigated in detail. A satisfactory explanation was arrived at to account for the experimental evidence.

Supportless PdFe nanorods as highly active electrocatalyst for proton exchange membrane fuel cell

The PdFe nanorods (PdFe-NRs) with tunable length were synthesized by an organic phase reaction of [Pd(acac) 2] and thermal decomposition of [Fe(CO) 5] in a mixture of oleyamine and octadecene at 160 °C. They show a better proton exchange membrane fuel cell (PEMFC) performance than commercial Pt/C in working voltage region of 0.80–0.65 V, due to their high intrinsic activity to oxygen reduction reaction (ORR), reduced cell inner resistance, and improved mass transport.

Kinetics of Epoxidation of Hydroxyl-Terminated Polybutadiene with Hydrogen Peroxide under Phase Transfer Catalysis

The epoxidation of hydroxyl-terminated polybutadiene (HTPB) via phase transfer catalysis (PTC) using H2O2 as the oxidant and ammonium tungstate hydrate and phosphoric acid as the cocatalysts was successfully carried out in an acidic solution/organic solvent two-phase medium. The microstructures of original and epoxidized HTPB products were confirmed by 1H NMR and 13C NMR. The influence of some process variables such as stirring speed, ammonium tungstate hydrate amount, Aliquat 336 amount, phosphoric acid amount, hydrogen peroxide amount, and reaction temperature on the epoxidation of HTPB were studied in detail. The reactions in organic phase were the rate-controlling steps. Based on the experimental results, a rational PTC mechanism was proposed and a pseudo-steady-state kinetic model was applied to describe the epoxidation of HTPB. The apparent kinetic constants for the three configurations in HTPB under the temperatures of 20−60 °C were determined (kapp,c = (2.7−6.43) × 10−2 min−1, kapp,t = (0.95−4.49)...

Kinetic Study of Synthesizing Dimethoxydiphenylmethane under Phase-Transfer Catalysis and Ultrasonic Irradiation

The synthesis of dimethoxydiphenylmethane (DMODPM) from the reaction of methanol and dichlorodiphenylmethane (DCDPM) was successfully carried out in a liquid−liquid phase-transfer catalytic (LLPTC) reaction assisted by ultrasonic irradiation. Little of the desired product DMODPM was obtained from the reaction in the presence of only potassium hydroxide and quaternary ammonium salts. The production of the DMODPM product was greatly enhanced when the reaction system was irradiated by ultrasonic waves. Two sequential reactions in the organic-phase solution proceed to produce the desired product. However, the second rate of the organic-phase reaction was faster than the first. Therefore, the first intermediate product, chloromethoxydiphenylmethane (CMODPM), was not detected during or after the reaction. A kinetic model was developed based on the experimental data. A pseudo-steady-state hypothesis (PSSH) was employed to describe the characteristic behaviors of the kinetic data. The results were finally described by a pseudo-first-order rate law, from which the apparent rate constant (kapp,1) of the first organic-phase reaction was obtained. The effects of the reaction conditions on the conversion of DCDPM and the reaction rate were investigated in detail, including the agitation speed; the amounts of methanol, DCDPM, water, chlorobenzene, potassium hydroxide, and tetrabutylammonium bromide (TBAB); the ultrasonic power and frequency; the organic solvents; the quaternary ammonium salts; and the temperature. Rational explanations are provided for the experimental results.

Equilibrium Studies on Enantioselective Liquid−Liquid Amino Acid Extraction Using a Cinchona Alkaloid Extractant

The enantioselective extraction of aqueous 3,5-dinitrobenzoyl-R,S-leucine (AR,S) by a cinchona alkaloid extractant (C) in 1,2-dichloroethane was studied at room temperature (294 K) in a batch system for a range of intake concentrations (10−4−10−3 mol/L) and pH values (3.8−6.6). The experimental data were described by a reactive extraction model with a homogeneous organic phase reaction of AR,S with C. Important parameters of this model were determined experimentally. The acid dissociation constant, Ka, of AR,S was (1.92 ± 0.07) × 10−4 mol/L. The physical distribution coefficient of AR,S between the organic and aqueous phase was 8.04 ± 0.39. The equilibrium constants of the organic phase complexation reaction were (9.31 ± 0.76) × 104 L/mol and (2.71 ± 0.76) × 104 L/mol for the S- and R-enantiomers, respectively. With these parameters an optimum performance factor, PF, of 0.19 was predicted. The PF was independent of the pH provided that pH ≫ pKa. The model was verified experimentally with excellent results (±7.9%).

Kinetic Study of Synthesizing 1-(3-Phenylpropyl)-pyrrolidine-2,5-dione under Solid−Liquid Phase-Transfer Catalysis

The synthesis of 1-(3-phenylpropyl)-pyrrolidine-2,5-dione (SUC-R) was successfully carried out from the reaction of succinimide (SUC-H) with 1-bromo-3-phenylpropane (RBr) in a small amount of KOH and organic solvent solid–liquid phase medium under phase-transfer catalysis (PTC) almost water-free conditions. The main purpose of this work was to determine the reaction conditions by examining the kinetic behavior, reaction mechanism, activation energy, and the related parameters in the solid–liquid PTC reaction. A rational mechanism for the reaction is proposed according to the experimental evidence. The reaction follows a pseudo-first-order rate law. A rate expression was developed to describe the kinetic behaviors from which the apparent rate constant (kapp) of the organic-phase reaction was obtained via experimental data. Kinetics of the reaction, including the effects of agitation speed, amount of water, amount of potassium hydroxide, temperature, amount of tetraoctylammonium bromide (TOAB), volume of cy...

Two-Phase Catalyzed S-Substitution of 2-Mercaptobenzimidazole by Tributylamine in the Presence of Potassium Hydroxide

The catalyzed S-substitution of 2-mercaptobenzimidazole (MBI or RSH) by tributylamine (TBA) was carried out in an alkaline solution of KOH/organic solvent two-phase medium. Tributylamine (TBA) reacts in situ with the organic-phase reactant, α-bromo-m-xylene (R′Br) to produce a quaternary ammonium salt ((C4H9)3R′NBr or QBr) which is used as the phase transfer catalyst. The reaction is greatly enhanced by adding a small amount of TBA in the presence of KOH. By appropriately controlling α-bromo-m-xylene (limited compound) at low KOH concentration, only the hydrogen atom connecting to the sulfur atom of 2-mercaptobenzimidazole was substituted byα-bromo-m-xylene. A kinetic model was developed in conjunction with the mass transfer of the catalyst (QBr) and the active intermediate (RSQ), as well as the reactions in both the aqueous and organic phases. The two-film theory is used to account for the mass transfer of QBr and RSQ between two phases. The experimental data verify that the mass transfer rate of the species between the two phases is larger than the reaction rate in the organic phase. The organic-phase reaction is the rate-controlling step for the whole two-phase reaction. A pseudo-steady-state hypothesis (PSSH) is employed to simplify the kinetic model, from which a pseudo-steady-state rate law is sufficiently used to describe the experimental data. Effects of the reaction conditions on the reaction rate and the conversion were investigated in detail.

Bicontinuous hydrogel–hydrophobic polymer systems through emulsion templated simultaneous polymerizations

Polymerization in the external phase of a high internal phase emulsion (HIPE) yields an emulsion templated, porous polyHIPE. This work describes the synthesis of novel bicontinuous hydrogel–hydrophobic polymer systems through simultaneous polymerization and cross-linking reactions in the HIPE's external organic-phase (styrene or 2-ethylhexyl acrylate with divinylbenzene) and internal aqueous-phase (acrylamide with N,N-methylenebisacrylamide). The ability to reversibly dry and hydrate these materials demonstrates their potential for biomedical and separation applications. The unexpected and significant reduction in the hydrated polyHIPE modulus with increasing acrylamide content in the aqueous-phase indicated that the polymerizations were not mutually exclusive and that the acrylamide affected the molecular structure of the hydrophobic polymer synthesized in the external phase. The locus of initiation (which can be in the aqueous-phase, organic-phase, or both) was also shown to have a profound affect on the molecular structure, porous structure, and properties.