Oleic Acid Moieties Research Articles

Design of Fluorinated Probes for Versatile Surface Functionalization and 19 F Magnetic Resonance Imaging.

The development of multifunctional nanoplatforms for bioimaging and therapy has attracted extensive attention in recent decades. As an emerging magnetic resonance imaging (MRI) technique, 19 F MRI effectively complements the limit of 1 H MRI owing to trace amount of 19 F atoms existing in the human body, affording high specificity. In this work, a novel molecule (CFO) containing hydrophilic fluorine fragments was synthesized using amino acids as starting materials, which could self-assemble into small nanoprobes via hydrophobic interactions of oleic acid moiety. The as-prepared nanoprobes displayed good relaxation performances thanks to the carboxylate group and sulfoxide group nearby. The nanoprobes successfully demonstrated its capacity for in-vivo 19 F MRI. In addition, CFO could be used as a general fluorine labeling agent for surface functionalization of nanoparticles, which provided a universal method for constructing water-soluble multifunctional nanoplatforms.

Membrane-active diacylglycerol-terminated thermoresponsive polymers: RAFT synthesis and biocompatibility evaluation

Well-defined diacylglycerol end-functionalized poly(N-isopropylacrylamide)s (PNIPAAm) and poly(N-vinylcaprolacam)s (PNVCL) with number-average molar masses (Mn) ranging from 1260 to 19 350 g·mol−1 were synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization from xanthate-functionalized diacylglycerols (DAGs) containing palmitic or oleic acid moieties. The formation of polymeric nanoparticles (PNPs) and their thermoresponsive properties was studied. Phase separation temperature dependence on polymer molar mass and hydrophilic/hydrophobic ratio was investigated in phosphate buffer saline (PBS). Biological tests showed that the particles are non-hemolytic and highly compatible with representatives of immune cells - monocyte/macrophage THP-1 cells. The biocompatibility combined with the potential ability to modulate the cell membrane environment make the proposed polymers a promising foundation for drug carriers.

Cellulose nanocrystals as a tunable nanomaterial for pervaporation membranes with asymmetric transport properties

The cost-effective recovery of alcohols from aqueous fermentation broths is crucial in the production of biofuels. In this context, pervaporation processes using dense membranes have attracted remarkable interest. Cellulose nanocrystals (CNCs) have emerged as a promising renewable component for membrane applications due to their high specific surface area and tunable surface chemistry. We recently reported compositionally graded nanocomposite membranes based on a hydrophobic poly(styrene)-block-poly(butadiene)-block-poly(styrene) (SBS) matrix and CNCs that display directional water transport properties. We here explore the ethanol-recovery pervaporation performance of such graded membranes for a model ethanol-water mixture. We further decorated the CNCs with hydrophobic oleic acid moieties (OLA-CNCs) and studied the impact of this modification on the structure and pervaporation performance of SBS/OLA-CNC nanocomposite membranes. Depending on the exposure side, SBS/CNC membranes exhibit either improved or diminished mass fluxes compared to the reference SBS membranes, but also a consistent reduction of the membrane selectivity towards ethanol. By contrast, the SBS/OLA-CNC membranes display increased ethanol permeability while their separation performance is comparable to the reference SBS membranes. Thus, we show that by tuning the surface chemistry of CNCs, the pervaporation properties and the degree of asymmetry in mass transport can be tailored.

Formation and properties of dark chocolate prepared using fat mixtures of cocoa butter and symmetric/asymmetric stearic-oleic mixed-acid triacylglycerols: Impact of molecular compound crystals

This paper reports an experimental study of the formation and properties of dark chocolate prepared using novel CB alternative fats (CBAs): symmetric (OSatO) and asymmetric (SatSatO) mixed-acid triacylglycerols (TAGs), in which Sat and O represent saturated fatty acids (stearic:S + palmitic:P) and oleic acid moieties, respectively. It was found that the ternary fat mixtures of CB/SatSatO/OSatO with a ratio of CB/(SatSatO + OSatO) of 1:1 formed the most stable β-form of the double chain length (DCL) structure (β-2), which revealed sufficient hardness and sharp melting profiles around body temperature without tempering processes. Fat bloom formation was not observed in dark chocolate with CBAs at ratios of CB/SatSatO/OSatO of 50/20/30–50/0/50 during the one-year storage test at temperatures between 15 °C and 30 °C. Overall, the present study has shown that fat mixtures made of CB/SatSatO/OSatO, which are rich in oleic acid moieties, can be employed as a cocoa butter equivalent (CBE) fat without tempering procedures.

A simple and efficient method for polymer coating of iron oxide nanoparticles

Iron oxide nanoparticles (IONP) have many possible uses including as MRI contrast agents, for drug delivery and cell labelling, but need to be stabilised and to be rendered biocompatible through appropriate coatings. Many current coatings are suboptimal, so we have investigated methodology to produce thin coatings using biocompatible polymers. We have produced uncoated IONP by a co-precipitation method in a range of sizes and subsequently coated the nanoparticles using poly(glycerol adipate) using the interfacial deposition method. To produce the necessary thin coatings a relatively small addition of polymer (approx. 0.1–0.2 mg polymer per 38 mg IONP) was necessary. A number of different PGA polymer variants with different physicochemical properties were used and the results suggested that the polymer properties also affected the coating process. Optimum coatings only a few nm thick (1–3 nm) were obtained with a linear poly(ethylene glycol)-PGA copolymer modified with 40% pendant oleic acid moieties. The resulting sterically stabilised IONP were stable against aggregation at and above physiological salt concentrations. Preliminary experiments demonstrated that the nanoparticles had relaxivity values comparable to commercially available IONP of a similar size and could be taken up readily by cells. This coating method therefore shows promise for a variety of medical applications.

Processing Induced Degradation Routes of Prochloraz in Rapeseed Oil.

Analyzing the fate of substances in complex matrices, such as processed food, is a major challenge in modern analytical chemistry. However, current regulatory procedures for pesticides only include high temperature hydrolysis of the active substance in water (OECD 507) to simulate food processing. This study shows that heating radiolabeled [imidazolyl-2-14C]prochloraz in virgin rapeseed oil at temperatures up to 240 °C leads to an extensive degradation of the active substance. In total, 11 degradation products were identified. Several of these products were formed by reactions of the active substance with ingredients from the oil. 2-[(1-H-Imidazole-1-carbonyl)(propyl)amino]ethyl oleate (icpame-oleate), a reaction product of an oleic acid moiety and the prochloraz backbone, was identified for the first time. The quantification of prochloraz, icpame-oleate, imidazole, and 2,4,6-trichlorophenol demonstrated the dependency of the degradation process on temperature, heating duration, and type of oil. The obtained results in this study show the enormous impact of high temperature food processing on the fate of pesticides. The necessity to consider matrix related reactions in pesticide regulation is emphasized, and the suitability of the OECD 507 guideline is questioned. Concerning possible toxicological risks of novel degradation products, future studies will have to assess potential hazards or opportunities of food processing, ultimately yielding in safer food.

Green epoxy synthesized from Perilla frutescens: A study on epoxidation and oxirane cleavage kinetics of high-linolenic oil

Despite the growing interest in epoxidized vegetable oils (EVOs) as sustainable alternatives to petroleum-based epoxies, their high epoxy equivalent weight (EEW) (>250 g/eq) hinders use in high-strength applications. This study reports the synthesis of a sustainable EVO that possesses EEW of ∼164 g/eq – comparable to that of diglycidyl ether of bisphenol-A (DGEBA). Non-edible perilla oil, extracted from the non-edible seeds of Perilla frutescens, was used to synthesize sustainable green epoxy via Prilezhaev epoxidation reaction at 40, 50 and 60 °C for 8 h. Perilla oil was chosen due to its higher number of chemically modifiable groups (>90%), i.e. ∼62–65 wt. % linolenic acid (C18:3), ∼13–15 wt. % linoleic acid (C18:2) and ∼12–15 wt. % oleic acid (C18:1) moieties. Rates of epoxidation and side reactions were estimated by experimentally determining iodine, epoxy and α-glycol value of epoxidized perilla oil (EPeO) extracted at regular time intervals during synthesis. Kinetics of post-oxirane cleavage was studied at aforementioned reaction temperatures and times by reacting EPeO with formic acid in weight ratio of 1:3. Reaction kinetics studies for both epoxidation and ring opening reactions (pseudo) showed reaction rate constants in the order of 10−6 L mol−1 s−1 (for both reactions) and activation energies of 20.10 kJ/mol (epoxidation) and 43.11 kJ/mol (ring opening) respectively. Thermodynamic parameters – such as activation enthalpy, activation entropy, and Gibbs’ free energy of activation – were calculated for both epoxidation and oxirane ring cleavage reactions. All the thermodynamic parameters were observed to be lower for epoxidation reaction compared to post-oxirane cleavage reaction. Enthalpy of activation was found to be ∼18 kJ/mol for epoxidation reaction while it was ∼56 kJ/mol for post-oxirane cleavage reaction.

A lipidomic cell-based assay for studying drug-induced phospholipidosis and steatosis.

Phospholipidosis and steatosis are two toxic effects, which course with overaccumulation of different classes of lipids in the liver. MS-based lipidomics has become a powerful tool for the comprehensive determination of lipids. LC-MS lipid profiling of HepG2 cells is proposed as an in vitro assay to study and anticipate phospholipidosis and steatosis. Cells with and without preincubation with a mixture of free fatty acids (FFA; i.e. oleic and palmitic) were exposed to a set of well-known steatogenic and phospholipidogenic compounds. The use of FFA preloading accelerated the accumulation of phospholipids, thus leading to a better discrimination of phospholipidosis, and magnified the lipidomic alterations induced by steatogenic drugs. Phospholipidosis was characterized by increased levels of phosphatidylcholines, phosphatidylethanolamines, phosphatidylserines, and phosphatidylinositols, while steatosis induced alterations in FA oxidation and triacylglyceride (TG) synthesis pathways (with changes in the levels of FFA, acylcarnitines, monoacylglycerides, diacylglycerides, and TG). Interestingly, palmitic and oleic acids incorporation into lipids differed. A characteristic pattern was observed in the fold of change of particular TG species in the case of steatosis (TG(54:3)>TG(52:2)>TG(50:1)>TG(48:0)). Based on the levels of those lipids containing only palmitic and/or oleic acid moieties a partial least squares-discriminant analysis model was built, which showed good discrimination among nontoxic, phospholipidogenic and steatogenic compounds. In conclusion, it has been shown that the use of FFA preincubation together with intracellular LC-MS based lipid profiling could be a useful approach to identify the potential of drug candidates to induce phospholipidosis and/or steatosis.

Phase behavior of binary mixture systems of saturated-unsaturated mixed-acid triacylglycerols: effects of glycerol structures and chain-chain interactions.

We systematically examined the phase behavior of binary mixtures of mixed-acid triacylglycerols (TAGs) containing palmitic and oleic acid moieties 1,3-dioleoyl-2-palmitoyl-glycerol (OPO), 1,2-dipalmitoyl-3-oleoyl-rac-glycerol (PPO), and 1,2-dioleoyl-3-palmitoyl-rac-glycerol (OOP), which are widely present in natural fats and are employed in the food, pharmaceutical, and cosmetic industries. Differential scanning calorimetry and X-ray diffraction methods were applied to observe the mixing behavior of PPO/OPO, OOP/OPO, and PPO/OOP under metastable and stable conditions. The results led to three conclusions: (1) Eutectic behavior was observed in PPO/OPO. (2) Molecular compound (MC) crystals were formed in the mixtures of OOP/OPO and PPO/OOP. (3) However, the MC crystals occurred only under metastable conditions and tended to separate into component TAGs to form eutectic mixture systems after 17 months of incubation. These results were contrary to those of previous studies on 1,3-dipalmitoyl-2-oleoyl glycerol (POP)/OPO and POP/PPO in which the MC crystals were thermodynamically stable. We determined that specific molecular interactions may cause this different phase behavior (stability of POP/OPO and POP/PPO MC crystals and metastability of OOP/OPO and PPO/OOP MC crystals). All results confirm the significant effects of molecular structures of glycerol groups, interactions of fatty acid chains, and polymorphism of the component TAGs on the mixing behavior of mixed-acid TAGs.

Synthesis, Characterization and Cytotoxicity Evaluation of an Oleic Acid Derived Novel Bicephalous Dianionic Surfactant

AbstractA novel oleic acid derived bicephalous dianionic surfactant disodium (Z) 3,3′‐(oleoylazanediyl)dipropanoate containing one hydrophobic carbon chain and two hydrophilic head groups was synthesized, characterized and evaluated for cytotoxicity for the purpose of introducing a new biocompatible surfactant. The head group 3,3′‐azanediyldipropanoate was synthesized through Michael addition of methyl acrylate to benzylamine and subsequent reductive debenzylation with Pd/C, H2 and was condensed with an oleic acid moiety via amide bond formation. Ester groups at the periphery were hydrolyzed using acetyl chloride‐water and the diacid formed was neutralized with sodium bicarbonate to obtain the desired surfactant. The CMC was determined by conductometry, log Poctanol/water by ChemSW software and the hydrophilic‐lipophilic balance (HLB) by the Davies method and ChemSW. In vitro cytotoxicity study was performed using sulforhodamine B assay and the in vivo skin irritation study was performed on male New Zealand white rabbits as per OECD guideline 404. The CMC was found to be 1.9 mm/l which was almost half of the CMC of sodium oleate. The Log Poctanol/water value of −3.87 and the HLB values of 35.22 and 34.46 by the Davies method and ChemSW software respectively revealed the hydrophilic nature of the surfactant. The surfactant did not exhibit any cytotoxicity at any of the concentrations tested and was found to be non‐irritating by in vivo skin irritation studies. The findings of the present work suggest that the synthesized novel bicephalous dianionic surfactant is a safe and biocompatible excipient. It has the potential to be an attractive alternative to linear and gemini surfactants for applications in biological studies and pharmaceutical drug delivery systems.

Acyclic triene metathesis (ATMET) miniemulsion polymerization of linseed oil produces polymer nanoparticles with comparable molecular weight to that of bulk reactions

Acyclic triene metathesis (ATMET) polymerizations of linseed oil were performed in bulk and miniemulsion to evaluate the activity of different types of ruthenium‐based catalysts (Grubbs 1st and 2nd generations, Hoveyda–Grubbs 2nd generation and Umicore M2) in both systems. Miniemulsion polymerizations with a nonionic surfactant resulted in polymer nanoparticles with an average size around 200 nm. The number‐average molecular weight (Mn) of the polymers, approximately 6 kDa, obtained by linseed oil metathesis miniemulsion polymerizations was found to be comparable to linseed oil metathesis bulk reactions if Umicore M2 and Hoveyda–Grubbs 2nd generation catalysts and nonionic surfactants were used. The presence of oleic acid moieties and saturated fatty acids in linseed oil limited the molecular weight increase and cross‐linking, since they act as chain‐stoppers. On the other hand, ATMET homopolymerization of glyceryl triundec‐10‐enoate (UDTG) with terminal double bonds led to a massive gel formation due to the three highly reactive terminal double bonds per molecule. Increasing the amount of linseed oil in ATMET copolymerization between linseed oil and UDTG resulted in lower gel content.Practical applications: Naturally occurring renewable plant oils as raw materials, without prior chemical modifications, are a very attractive alternative to fossil reserves. Linseed oil contains about 90% unsaturated fatty acids. This property makes it suitable for ATMET polymerization, including the miniemulsion technique, allowing the synthesis of branched macromolecular nanoparticles. The ratio of linseed oil and glyceryl triundec‐10‐enoate (UDTG) in ATMET copolymerization can tune the gel content, as the presence of oleic acid moieties and saturated fatty acids in linseed oil limits the cross‐linking.Branched macromolecule nanoparticles were obtained by ATMET miniemulsion polymerization of linseed oil.

Retardation of Crystallization of Diacylglycerol Oils Using Polyglycerol Fatty Acid Esters

AbstractLiquid oil containing high concentrations of diacylglycerols (DAG > 80 %, hereafter referred to as DAG‐rich oil) is generally more likely to cause precipitation at chilled temperatures (clouding phenomena) than triacylglycerol‐based oil. The clouding phenomena that occur during long‐term storage of DAG‐rich oil are unwanted in consumer products and therefore, must be prevented. In the present study, we attempted to retard precipitation by adding food emulsifiers, polyglycerol fatty acid esters (PGFE) containing different fatty acid moieties. DSC, polarized optical microscopy, and X‐ray diffraction studies revealed that the addition of 0.2 % PGFE containing palmitic and oleic acid moieties very effectively retarded precipitation in the DAG‐rich oil. To confirm these observations, we prepared a model DAG oil to mimic DAG‐rich oil and examined the retardation behavior of high‐melting DAG fractions using PGFE. The results are discussed in terms of the effects of PGFE additives on the pre‐nucleation processes of high‐melting fractions in DAG‐rich oil.

Effects of Polyglycerine Fatty Acid Esters Having Different Fatty Acid Moieties on Crystallization of Palm Stearin

We studied the effects of adding emulsifiers, specifically polyglycerine fatty acid esters (PGFEs), on the crystallization of palm stearin (PS), using synchrotron radiation X-ray diffraction and DSC methods. Our main aim was to examine the effects of the molecular shapes of PGFEs containing palmitic and oleic acid moieties at different ratios, the concentration of PGFE additives, and the cooling rate on the crystallization kinetics of PS in combined ways. We found that all PGFE additives retarded the crystallization of PS when the concentration of PGFEs was low and the cooling rate was low. However, crystallization was promoted when the concentration of PGFEs containing a high amount of palmitic acid moiety was increased and the cooling rate was increased. It was evident that the additive effects due to the PGFEs became less remarkable with increasing concentrations of oleic acid moiety. By contrast, emulsifiers containing palmitic acid moiety strongly affected the crystallization. We discuss the fact that crystallization was promoted by the template effects of PGFEs but was retarded by the disturbance of nucleation and subsequent crystal growth processes caused by the PGFE molecules.

Structures and Binary Mixing Characteristics of Enantiomers of 1‐Oleoyl‐2,3‐dipalmitoyl‐sn‐glycerol (S‐OPP) and 1,2‐Dipalmitoyl‐3‐oleoyl‐sn‐glycerol (R‐PPO)

AbstractWe performed differential scanning calorimetry (DSC) and synchrotron radiation X‐ray diffraction (SR‐XRD) experiments of polymorphic structures and binary mixing characteristics of the enantiomers of 1‐oleoyl‐2,3‐dipalmitoyl‐sn‐glycerol (S‐OPP) and 1,2‐dipalmitoyl‐3‐oleoyl‐sn‐glycerol (R‐PPO). In the two enantiomers, oleic and palmitic acid moieties are asymmetrically connected at the sn‐1 and sn‐3 positions of the glycerol groups, with palmitic acid moiety at the sn‐2 position. Pure enantiomer samples (>99 %) were synthesized and employed throughout this study. The following results were obtained. (1) A basic feature of the mixture systems of S‐OPP and R‐PPO is of a eutectic nature due to different polymorphic structures of two enantiomers and the racemic compound of PPO (rac‐PPO). (2) Polymorphic behavior of S‐OPP and R‐PPO was quite similar, both having α‐2 and β′‐3, whereas rac‐PPO contained α rac‐3, β′rac‐2, and β′rac‐3. The DSC measurements showed that the melting points of β′‐3 (S‐OPP = 35.3 °C and R‐PPO = 34.9 °C) were higher than that of β′rac‐3 (31.0 °C). β was not crystallized in the pure enantiomers, and rac‐PPO. (3) αrac‐3 was crystallized at low cooling rates (~2 °C/min), whereas α‐2 of the two enantiomers was crystallized only with very rapid cooling (~10 °C/min). (4) Triple‐chain‐length structures were formed in αrac‐3, β′S‐3 (=β′R‐3), and β′rac‐3; α‐2 with a double‐chain‐length structure was formed in both enantiomers. These results indicate the importance of the relationship between subcell packing and glycerol conformation in the polymorphism and mixing characteristics of asymmetric unsaturated–saturated‐saturated mixed‐acid triacylglycerols.

Surface Chemistry of CdTe Quantum Dots Synthesized in Mixtures of Phosphonic Acids and Amines: Formation of a Mixed Ligand Shell

Solution nuclear magnetic resonance (NMR) spectroscopy is used to analyze the surface chemistry of CdTe quantum dots (QDs) synthesized in the presence of tetradecylphosphonic acid and oleylamine. The resulting CdTe QDs have a mixed capping, composed of tightly bound phosphonate anhydride and amine ligands. The overall ligand density is relatively low, which concurs with a low Cd excess in the QDs. We find that upon addition of oleic acid, neither amine or phosphonate anhydride ligands are released from the QDs. On the other hand, the addition of phosphonic acids to CdTe QDs partially capped by oleic acid moieties through a high temperature ligand exchange process leads to the ready, one-to-one release of oleic acid. A full thermodynamic analysis of the phosphonate/carboxylate exchange is however not possible since the exchange appears to be modified by the forced ligand exchange used to replace phosphonate by carboxylate ligands.

Crystallization Behavior of Diacylglycerol‐Rich Oils Produced from Rapeseed Oil

AbstractWe examined the crystallization behavior of high‐melting fractions in liquid oil containing high concentrations of diacylglycerols (DAG >80%) (hereafter referred to as DAG‐rich oil). By differential scanning calorimetry and optical microscopy at moderate cooling rates, crystallization in the DAG‐rich oil was detected at around 6 °C. It was found that the crystallization extent increased with decreasing temperatures of crystallization below 0 °C. A gas chromatographic analysis was performed on the crystallized fractions, which were separated by filtration at different periods of isothermal crystallization at 3 °C. The results indicated that at earlier crystallization periods, the concentrations of 1,3‐disaturated DAG such as palmitic and stearic acid moieties (15 min) and 1,3‐saturated–unsaturated mixed‐acid DAG including oleic acid, palmitic, and stearic acid moieties (15 min–3 h) were predominant. However, the concentrations of 1,3‐diunsaturated DAG including oleic acid moiety increased after a crystallization period of 6 h. To clarify the sequential crystallization process of DAG, we examined the binary mixing behavior of principal DAG components occurring in the rapeseed‐based DAG‐rich oil. It was evident that 1,3‐disaturated DAG, 1,3‐saturated–unsaturated mixed‐acid DAG, and 1,3‐diunsaturated DAG exhibited immiscible behavior. From these data, basic information on the precipitation processes in DAG‐rich oils at chilled temperatures was obtained.

Novel paper sizing agents based on renewables. Part 5: characterization of maleated oleates by ozonolysis

Abstract Maleated high oleic sunflower oil (maleated SOHO, MSOHO) is a promising substitute for alkenyl succinic anhydrides (ASA) that are widely used as sizing agents for paper. The part of the MSOHO molecule that is believed to be responsible for adhesion of the molecule onto cellulose, i.e., the maleated oleic acid moiety, was separately prepared and analytically characterized. Structural analysis was completed by studies of the molecular fragments obtained upon ozonolysis. The interesting question of whether there was a preferential reactivity during the ene-reaction of maleic anhydride with oleates was answered in a way that the newly formed double bond was placed to either side with no apparent selectivity.

Enantiomeric separation of asymmetric triacylglycerol by recycle high-performance liquid chromatography with chiral column

In our previous studies, we employed recycle HPLC for the separation of triacylglycerol (TAG)-positional isomers (PIs). In this study, a recycle HPLC system equipped with a polysaccharide-based chiral column was applied to the enantiomeric separation of some asymmetric TAGs having straight-chain C16–C18 acyl residues. As a result, 1,2-dipalmitoyl-3-oleoyl- rac-glycerol ( rac-PPO), 1,2-dioleoyl-3-palmitoyl- rac-glycerol ( rac-OOP), and 1,2-dipalmitoyl-3-linoleoyl- rac-glycerol ( rac-PPL) were resolved into their respective enantiomers. However, neither 1,2-dioleoyl-3-linoleoyl- rac-glycerol ( rac-OOL), consisting of only unsaturated fatty acids, nor 1,2-dipalmitoyl-3-stearoyl- rac-glycerol ( rac-PPS), consisting of only saturated fatty acids, was resolved. These results suggest that the asymmetric TAGs, used in this study, having both a palmitic acid moiety and an oleic acid (or a linoleic acid) moiety at the sn-1 or sn-3 positions are resolved by the chiral column. This new chiral separation method can be used in combination with atmospheric pressure chemical ionization mass spectrometry to determine the sn-OOP/ sn-POO ratio in palm oil. This method is applicable for the chiral separation of asymmetric TAGs in palm oil.

Phase Behavior of a Binary Mixture of 1,3-Dipalmitoyl-2-oleoyl-sn-glycerol and 1,3-Dioleoyl-2-palmitoyl-sn-glycerol in n-Dodecane Solution

The phase behavior of a binary mixture of triacylglycerol (TAG), POP (1,3-dipalmitoyl-2-oleoyl-sn-glycerol), and OPO (1,3-dioleoyl-2-palmitoyl-sn-glycerol) in an organic solvent, n-dodecane, was examined by DSC and synchrotron radiation X-ray diffraction (SR-XRD). In our previous study on POP-OPO mixtures in neat liquid, the formation of molecular compound (MC) crystals of POP/OPO = 50/50 was observed (Minato et al. J. Am. Oil Chem. Soc. 1997, 74, 1213-1220). The purpose of the present study was to determine whether MC is formed in the POP-OPO mixture system in diluted solution when n-dodecane (C(12)) is added to the mixture as a solvent. Two solution systems having weight concentration ratios of POP and OPO to n-dodecane ((POP+OPO):C(12)) of 50:50 (50% solution) and 20:80 (20% solution) were prepared. We found that MC formed at a ratio of POP/OPO = 50/50 in both 50% solution and 20% solution in the stable and metastable states. Differences between the neat liquid and solution systems appeared in two results. In the first, the melting temperatures of MC crystals were lowered from 32.0 degrees C (neat liquid) to 20.4 degrees C (50% solution) and 18.0 degrees C (20% solution). In the second, the beta polymorph of the MC was always observed in the two solutions under the conditions examined in the present study, whereas alpha and beta polymorphs were observed in the neat liquid. These differences were caused by thermodynamic solvent effects. However, we conclude that aliphatic chain-chain interactions through palmitic and oleic acid moieties forming the MC of POP-OPO having a double chain length structure are not disturbed by solute-solvent interactions.

Bulk Synthesis of Monodisperse Ferrite Nanoparticles at Water−Organic Interfaces under Conventional and Microwave Hydrothermal Treatment and Their Surface Functionalization

Synthesis of monodisperse MFe2O4 (M =, Ni, Co, Mn) and γ-Fe2O3 nanoparticles at a water−toluene interface under conventional as well as microwave hydrothermal conditions using readily available nitrate or chloride salts and oleic acid as the dispersing agent is described. The ensuing particles were monodispersed with a size distribution ranging from 5 to 10 nm. The process is atom-efficient and can be scaled up to a level of several grams without downsizing the size and shape. The modulation of solubility profile of the particles was accomplished via functionalization using organic moieties. X-ray diffraction confirmed the formation of cubic spinel nanostructures. Particle sizes calculated from the Scherrer formula and TEM micrographs were comparable. ICP−AES studies confirmed that the ratios of Fe to Ni, Mn, and Co were approximately equal to 2. FT-IR confirmed the presence of oleic acid moieties on the surface of the synthesized particles. At room temperature, the particles were found to be superparamag...