Undecylenic Acid Research Articles

Theoretical and Kinetic Analysis of the Esterification of Undecylenic Acid with Glycerol.

The synthesis of undecylenic acid partial esters can be performed at mild temperature with a classical esterification reaction catalyzed by dodecylbenzene sulfonic acid (DBSA). A semi-empirical molecular modeling on the different reaction intermediates indicates that DBSA can strongly decrease their heats of formation through hydrogen bonding. Diester formation seems to be thermodynamically favored with a selectivity for alpha, alpha, or alpha, beta forms that depend on the geometry of the catalyst-intermediate configuration. Triesters are not favored but a high selectivity for monoesters requires a kinetic control. Experimental approach, considering different DBSA concentrations and temperature partially confirms the theoretical predictions but surfactant properties of DBSA and monoesters may induce nonpredicted geometries. Global apparent activation energies are calculated, corresponding to the formation and hydrolysis of mono and diesters. If water trapping allows the decrease of hydrolysis reaction constants, the presence of water and subsequent phase separation may explain differences between theoretical and experimental results and could help increasing monoester selectivity.

Investigation of the structure and mechanisms of thermal motion in nanostructured undecylenic acid

We have compared the structure, phase transitions and the thermal motion mechanisms of the undecylenic acid in bulk and inside a porous matrix using powder X-ray diffraction, calorimetry and IR-spectroscopy methods. The matrix used was a porous silicon with cylindrical pores (D = 20 nm). The interaction between the walls of the porous silicon and the nanocrystals of the undecylenic acid results in a crystalline structure, which is significantly different from the structure of bulk undecylenic acid. A phase transition in the wall-adjacent layer of the undecylenic acid nanocrystals was shown to take place. The solid-state phase transition temperatures, as well as the melting point, were shown to be lower for nanocrystals. Topological soliton motion mechanism was suggested to explain the thermal motion of the undecylenic acid molecules in the rotator phase.

Predictive models for characterizing the atomization process in pyrolysis of methyl ricinoleate

Abstract Pyrolysis of methyl ricinoleate (MR) can produce undecylenic acid methyl ester and heptanal which are important chemicals. Atomization feeding favors the heat exchange in the pyrolysis process and hence increases the product yield. Herein, predictive models to characterize the atomization process were developed. The effect of spray distance on Sauter mean diameter (SMD) of atomized MR droplets was examined, with the optimal spray distance to be 40–50 mm. Temperature mainly affected the physical properties of feedstock, with smaller droplet size obtained at increasing temperature. In addition, pressure had significant influence on SMD and higher pressure resulted in smaller atomized droplets. Then, a model for SMD prediction, combining temperature, pressure, spray distance, and structural parameters of nozzle, was developed through dimensionless analysis. The results showed that SMD was a power function of Reynolds number (Re), Ohnesorge number (Oh), and the ratio of spray distance to diameter of swirl chamber in the nozzle (H/dsc), with the exponents of − 1.6618, − 1.3205 and 0.1038, respectively. The experimental measured SMD was in good agreement with the calculated values, with the error within ± 15%. Moreover, the droplet size distribution was studied by establishing the relationship between the standard deviation of droplet size and SMD. This study could provide reference to the regulation and optimization of the atomization process in MR pyrolysis.

Synthesis and Physicochemical Characterization of Undecylenic Acid Grafted to Hyaluronan for Encapsulation of Antioxidants and Chemical Crosslinking.

In this work, a new amphiphilic derivative made of 10-undecylenic acid grafted to hyaluronan was prepared by mixed anhydrides. The reaction conditions were optimized, and the effect of the molecular weight (Mw), reaction time, and the molar ratio of reagents was explored. Using this methodology, a degree of substitution up to 50% can be obtained. The viscosity of the conjugate can be controlled by varying the substitution degree. The physicochemical characterization of the modified hyaluronan was performed by infrared spectroscopy, Nuclear Magnetic Resonance, Size-Exclusion Chromatography combined with Multiangle Laser Light Scattering (SEC-MALLS), and rheology. The low proton motility and self-aggregation of the amphiphilic conjugate produced overestimation of the degree of substitution. Thus, a novel method using proton NMR was developed. Encapsulation of model hydrophobic guest molecules, coenzyme Q10, curcumin, and α-tocopherol into the micellar core was also investigated by solvent evaporation. HA-UDA amphiphiles were also shown to self-assemble into spherical nanostructures (about 300 nm) in water as established by dynamic light scattering. Furthermore, HA-UDA was crosslinked via radical polymerization mediated by ammonium persulphate (APS/TEMED). The cross-linking was also tested by photo-polymerization catalyzed by Irgacure 2959. The presence of the hydrophobic moiety decreases the swelling degree of the prepared hydrogels compared to methacrylated-HA. Here, we report a novel hybrid hyaluronan (HA) hydrogel system of physically encapsulated active compounds and chemical crosslinking for potential applications in drug delivery.

Adsorption of water and fatty acids at magnesium hydroxide surface from an MDS perspective

The adsorption characteristics of fatty acids at the magnesium hydroxide (Mg(OH)2) surface are crucial in the wet surface modification process for the preparation of apyrous high-polymer materials and the concentration of brucite by flotation. In this regard, the interfacial water structures at the magnesium hydroxide (001), (101), (102) and (110) surfaces were examined and compared. The adsorption of fatty acids – namely, undecylenic acid (C11H20O2), lauric acid (C12H24O2), oleic acid (C18H34O2) and stearic acid (C18H36O2) – and their hydrophobicity at the magnesium hydroxide (001) surface were investigated by molecular dynamics simulation (MDS). The results indicate that the magnesium hydroxide (101) and (001) surfaces have the greatest and least effect on the interfacial water structure, respectively. The fatty acids overall have similar adsorption affinity at the magnesium hydroxide (001) cleavage surface, while the chemical reaction mainly contributes to the fatty acid adsorption at the magnesium hydroxide (001) surface. The hydrophobicity of the magnesium hydroxide surface increases as a function of the carbon (C) chain length with the adsorption of fatty acids. The presented results improve the fundamental understanding of fatty acid adsorption at the magnesium hydroxide surface, which will help enhance and/or support the robust performance of magnesium hydroxide wet surface modification and brucite flotation.

Hierarchical Nanostructuring of Porous Silicon with Electrochemical and Regenerative Electroless Etching.

Hierarchically nanostructured silicon was produced by regenerative electroless etching (ReEtching) of Si powder made from pulverized anodized porous silicon. This material is characterized by ∼15 nm mesopores, into the walls of which tortuous 2-4 nm pores have been introduced. The walls are sufficiently narrow that they support quantum-confined crystallites that are photoluminescent. With suitable parameters, the ReEtching process also provides control over the emission color of the photoluminescence. Ball milling and hydrosilylation of this powder with undecylenic acid produces nanoparticles with hydrodynamic diameter of ∼220 nm that exhibit robust and bright luminescence that can be excited with either one ultraviolet/visible photon or two near-infrared photons. The long-lived, robust visible photoluminescence of these chemically passivated porous silicon nanoparticles is well-suited for bioimaging and theranostic applications.

Synthesis from Undecylenic Acid of Macroheterocycles with Diacylhydrazine and Ester Fragments

A three-step synthesis of potentially biologically active 30- and 32-membered macroheterocycles with esters and acylhydrazines starting from methyl undecylenate was developed based on [1+1]-condensation of intermediate tetraesters, i.e., bis(10′ -methoxy-10′-oxodecyl)- or bis(11′-methoxy-11′ -oxoundecyl)hexanedioate, with hydrazine hydrate. The structures of the synthesized compounds were confirmed using IR and NMR spectroscopy and mass spectrometry.

Identification of undecylenic acid as EAG channel inhibitor using surface plasmon resonance-based screen of KCNH channels

BackgroundKCNH family of potassium channels is responsible for diverse physiological functions ranging from the regulation of neuronal excitability and cardiac contraction to the regulation of cancer progression. KCNH channels contain a Per-Arn-Sim (PAS) domain in their N-terminal and cyclic nucleotide-binding homology (CNBH) domain in their C-terminal regions. These intracellular domains shape the function of KCNH channels and are important targets for drug development.MethodsHere we describe a surface plasmon resonance (SPR)-based screening method aimed in identifying small molecule binders of PAS and CNBH domains for three KCNH channel subfamilies: ether-à-go-go (EAG), EAG-related gene (ERG), and EAG-like K+ (ELK). The method involves purification of the PAS and CNBH domains, immobilization of the purified domains on the SPR senor chip and screening small molecules in a chemical library for binding to the immobilized domains using changes in the SPR response as a reporter of the binding. The advantages of this method include low quantity of purified PAS and CNBH domains necessary for the implementation of the screen, direct assessment of the small molecule binding to the PAS and CNBH domains and easiness of assessing KCNH subfamily specificity of the small molecule binders.ResultsUsing the SPR-based method we screened the Spectrum Collection Library of 2560 compounds against the PAS and CNBH domains of the three KCNH channel subfamilies and identified a pool of small molecules that bind to the PAS or CNBH domains. To further evaluate the effectiveness of the screen we tested the functional effect of one of the identified mEAG PAS domain specific small molecule binders on currents recorded from EAG channels. Undecylenic acid inhibited currents recorded from EAG channels in a concentration-dependent manner with IC50 of ~ 1 μM.ConclusionOur results show that the SPR-based method is well suited for identifying small molecule binders of KCNH channels and can facilitate drug discovery for other ion channels as well.

Multifunctional polyurethane coatings derived from phosphated cardanol and undecylenic acid based polyols

Renewable resource based polyol derived from undecylenic acid, a by-product of castor oil, was successfully synthesized by three consecutive reactions: methylation, thiol-ene addition, and amidation. The biobased polyol is a sulfur- and nitrogen-containing polyol. The structure was confirmed by FTIR, NMR, and mass spectroscopic techniques. The undecylenic acid based polyol was used as a polyol along with phosphated cardanol-based polyol in the preparation of polyurethane coatings. The obtained polyurethanes were assessed for their properties by various techniques such as thermogravimetric analysis (TGA), dynamic mechanical and thermal analysis (DMTA), Universal testing machine (UTM) and electrochemical study. Interestingly, the biobased polyol improved mechanical property such as toughness of the material when it was incorporated in different weight percentages to the phosphated cardanol-based polyol. Moreover, the synergistic effect of the phosphorous and biobased polyol with the elements - sulfur and nitrogen, enhanced the anti-corrosion and antimicrobial natures of the polyurethane coating. The corrosion rate was drastically decreased from 3.0 × 10–4 to 1.8 × 10–7 mm per year for the prepared polyurethane coatings.

Both Penicillium expansum and Trichothecim roseum Infections Promote the Ripening of Apples and Release Specific Volatile Compounds.

Blue mold and core rot caused by Penicillium expansum and Trichothecium roseum are major diseases of apple fruit in China; however, their differential aggressiveness in apples and effect on fruit postharvest physiology are unclear. The effects of colonization of apples cv. Red Delicious by both pathogens were compared to physiological parameters of ripening and release of volatile compounds (VOCs). P. expansum colonization showed increased aggressiveness compared to T. roesum colonization of apple fruits. P. expansum enhanced colonization occurred with differential higher ethylene production and respiratory rate evolution, lower membrane integrity and fruit firmness in correspondence with the colonization pattern of inoculated apples. Moreover, P. expansum caused lower contents of total soluble solid and titratable acid, and higher malondialdehyde compared with T. roesum colonization. While both pathogen infections enhanced VOCs release, compared with T. roseum inoculated apples, P. expansum inoculated apple showed a higher total VOCs production including alcohols, aldehydes and esters, being the C6 alcohols, aldehydes and esters amount. PLS-DA analysis indicated that hexanoic acid was the most important factor to distinguish the inoculated fruits from the controls. Interestingly, propyl acetate and hexyl benzoate, and undecylenic acid and hexadecane were only identified in the P. expansum and T. roseum inoculated fruits, respectively. Taken together, our findings indicate that both fungi inoculations promote apple fruit ripening and release specific VOCs; moreover, apple fruits are more susceptible to P. expansum colonization than T. roesum.

Photoemissive properties and stability of undecylenic acid-modified porous silicon nanoparticles in physiological medium

Porous silicon nanoparticles (PSiNPs) are non-toxic photoluminescence imaging agents whose potential for biophotonic applications has been widely reported in recent years. However, this material suffers from intrinsic limitations, due to its chemical instability and rapid photoluminescence extinction on exposure to the physiological environment. In this letter, a mild functionalization procedure for PSiNP stabilization, based on undecylenic acid conjugation via hydrosilylation, is proven to be effective under simulated biological conditions [phosphate-buffered saline (PBS) 0.1 M, pH = 7.4]. Once stored in isopropanol, bare and hydrosilylated PSiNPs (h·PSiNPs) show similar photoemissive properties: photoluminescence quantum yield (>10%), steady-state spectra, and emission lifetime. Interestingly, the behaviour of these nanoparticles is completely different in the physiological medium: the morphology and the photoluminescence emission of bare PSiNPs completely degrade within 2 h, whereas a full preservation of the same features up to 6 h is demonstrated for h·PSiNPs.

Evaluating the Effects of a Topical Preparation with Dexpanthenol, Silbiol, Undecylenic Acid, and Lidocaine on Palatal Mucosa Wound Healing in a Rat Model

Background:Postoperative complications occur after periodontal plastic surgeries, but an ideal treatment to overcome them has not been found yet.Aims:To evaluate the effects of topically applied Oral-norm gel on the healing of excisional wounds.Study Design:Animal experiment.Methods:Excisional wounds with a diameter of 3 mm were made in the center of the palatal mucosa of 63 Sprague Dawley rats. Seven animals were sacrificed at time 0. The remaining rats were divided into two groups: a test group in which the topical Oral-norm gel was applied three times a day and a control group in which nothing was applied. Seven animals in each group were sacrificed at 3, 7, 14, and 21 days. Mean wound surface area was measured photographically, while wound healing and width were evaluated microscopically.Results:The mean wound surface area decreased significantly after 3 days in both groups (p<0.001). Between days 3 and 7, the mean wound surface area decreased from 6.62 (2.85) to 0.83 (1.62) mm2 in the control group and 5.07 (0.88) to 1.42 (1.67) mm2 in the test group. The wound width decreased significantly on day 7 in both groups (p<0.001), with no further changes by day 14. Both groups had a significant increase in inflammation and vascularization on day 3 (p<0.001), with a reduction thereafter. No significant differences in macroscopic and microscopic measurements were observed between the groups at any time point (p>0.05).Conclusion:The Oral-norm gel has no positive healing effects in the palatal mucosa of rats.

Structure of Mixed Acid/Decyl Monolayers Grafted on Oxide-Free Si(111) Surfaces.

The structure of mixed acid/decyl monolayers (MLs) grafted on oxide-free Si(111) surfaces by photochemical hydrosilylation in a mixture of neat undecylenic acid and 1-decene is studied in detail. After appropriate surface cleaning of the as-grafted surfaces, atomic force microscopy (AFM) (topography and phase imaging) and calibrated FTIR analysis demonstrate that a mixed monolayer is formed, free of residue. When the acid-molecule fraction (ΓSOL) is >0.1, mixed MLs are homogeneous on the scale of observations and they are only slightly enriched in acid chains with respect to the solution. Conversely, when ΓSOL < 0.1, the acid chain fraction within the ML becomes quasi-independent of the solution composition and may become much larger than ΓSOL. In addition, dark domains are observed in AFM phase images. Correlations between the characteristic parameters of νCO IR bands and AFM phase images suggest a strong phase separation of acid and alkyl chains at various length scales. A model involving a structuration of the grafting solution is proposed to explain observations.

Characterization and fatty acid profile analysis of oil extracted from unexploited seed of African star apple (Udara)

This study sought to characterize the phyto-oil extracted from an unexploited seed of African star apple (Udara) using soxhlet extraction method, normal hexane was used as the solvent at 67 °C for 4 h. The percentage oil yield was 23.8%. The extracted oil was liquid at room temperature, pleasant sweet smell with honey-like colour. The oil physicochemical properties such as acid value, peroxide value and saponification value were 17.41 ± 0.43 mg/KOH/g, 57.74 ± 2.77 meq/kg−1 and 236.341 ± 6.80 mg/KOH/g, respectively. Also, free fatty acid of 8.75% and iodine value of 29 ± 0.16 mg/100g were obtained. The identified fatty acids present included n-hexadecanoic acid (7.55%), 13-hexyloxacyctri-dec-10-en-2-one (1.19%), oleic acids (30.21%), octadecanoic acid (5.28%), hexadecanoic acid (2.37%), undecylenic acid (40.33%), 9-octadecanal (7.09%), and 9, 17-octadecadienal (5.98%). The properties of oil extracted revealed that the seed is a good source of oil which could be employed for industrial purposes.

Novel pH-Responsive Smart Fabric: From Switchable Wettability to Controllable On-Demand Oil/Water Separation

Stimulus-responsive materials have great potential in advanced controllable oil/water separation applications. Here, a novel, cost-effective, and green approach is developed to produce a pH-responsive smart fabric with switchable wettability. The approach first involves grafting polydopamine (PDA) and cystamine dihydrochloride (cystamine) on a fabric surface to obtain thiol-functionalized fabric (Fabric-SH). Hydrophobic stearyl methacrylate (SMA) and pH-responsive undecylenic acid are then decorated on the Fabric-SH surface through efficient and green photoinduced thiol–ene click coupling chemistry. The obtained fabric exhibits rapidly switchable wettability between superhydrophobicity and superhydrophilicity depending on the contacting liquid pH value and can be applied in controllable separation of various mixtures of water and oil with high efficiency up to 99%. More importantly, the as-prepared fabric is able to realize the separation of oil/water/oil ternary mixtures and can self-clean and repel oil ...

Synthesis and Characterization of Novel Polyol Esters of Undecylenic Acid As Ecofriendly Lubricants

AbstractThree novel esters of undecylenic acid (UA) were synthesized using the following polyols: linear diglycerol (DG), pentaerythritol monomethylether (PEME), and trimethyloltoluene (TMT). They were characterized through density, viscosity, thermo‐oxidative stability, melting point (m.p.), miscibility with mineral oils, and toxicity to evaluate their potential as ecofriendly lubricants. Trimethylolpropane (TMP) triundecylenate was also synthesized and characterized as a reference ester. Esters’ densities were in the range 0.93–0.97 g cm−3. The PEME ester showed a kinematic viscosity of 25.2 cSt at 40°C, only slightly higher than that of TMP ester (24.7 cSt), both of them near the ISO VG 22 class, while DG and TMT esters were near the ISO VG 32 class, with viscosities of 28.3 and 37.1 cSt, respectively. PEME and TMT esters were similar in thermo‐oxidative stability and more stable than their corresponding oleate esters. The m.p. of TMT ester was remarkedly low (−54°C), showing its potential for very cold temperature applications. TMT ester was found to be nontoxic against Artemia salina (LC50 &gt; 1000 μg mL−1), an initial indication of nontoxicity of UA esters in aquatic media. The synthesized esters showed potential to be applied as ecofriendly lubricants.

Evaluating the Effects of a Topical Preparation Composed of Dexpanthenol, Silbiol, Undecylenic Acid and Lidocaine on Palatal Mucosa Wound Healing in a Rat Model

Evaluating the Effects of a Topical Preparation Composed of Dexpanthenol, Silbiol, Undecylenic Acid and Lidocaine on Palatal Mucosa Wound Healing in a Rat Model

PSS51 - ANALYSIS OF TOPICAL PREPARATIONS FOR TREATMENT OF ONYCHOMYCOSIS IN UKRAINE

Therapeutic options for onychomycosis include oral and topical antifungals. Since topical medicines are used both in monotherapy, and in combination therapy, the aim of this work was to conduct comparative analysis of topical preparations for treatment of onychomycosis included into clinical protocol and State Formulary of Ukraine. comparative analysis of topical medicines included into clinical protocol and State Formulary of Ukraine, 10th edition. Clinical protocol for treatment of onychomycosis (CP) was approved by Ministry of Health of Ukraine in 2012. It recommends three onycholytic preparations with urea to remove infected nail plate, and than to treat a nail bed with either antifungal lacquer or topical preparation with ketoconazole, terbinafine, oxiconazole, miconazole, chlornitrophenol, undecylenic acid, combination preparation with ketoconazole and salicylic acid. The last preparations are listed without indication of a preferred dosage form. State Formulary of Ukraine, 10th (SFU) was approved by Ministry of Health of Ukraine in 2018. SFU also recommends applying antifungals onto nail bed after nail plate removal, but it does not recommend any onycholytic preparations. Furthermore, among 42 topical antifungal preparations included into SFU, only four antifungals are recommended for onychomycosis treatment. These are bifonazole cream, econazole cream, gel and cream with miconazole. Neither ketoconazole nor other topical antifungal preparation listed in CP, except of miconazole, are specified by SFU to be effective for onychomycosis. Antifungal lacquers are not included into SFU at all. There are gaps between CP and SFU. CP should be reviewed in accordance to data of evidence-based medicine. Despite the fact that a new edition of SFU was recently published, it does not include antifungal lacquers, which are broadly used and recommended, for example, by British National Formulary. Thus, it is also necessary to analyze antifungal nail lacquers for making decision about including them into SFU.

Pyrolysis of methyl ricinoleate by microwave-assisted heating coupled with atomization feeding

A stable high-temperature reaction site and the uniformity and speed of heating the feedstocks play a key role in pyrolysis processes. In this study, microwave-assisted heating coupled with atomization feeding was used to pyrolyze methyl ricinoleate (MR) for the efficient, continuous production of undecylenic acid methyl ester (UAME) and heptanal (HEP). The effects of feed mode, reaction temperature and preheating temperature on microwave-assisted pyrolysis (MAP) were examined. The maximum selectivities of HEP and UAME could reach 91.4 wt.% and 76.6 wt.%, respectively, at the reaction and preheating temperatures of 500 °C and 150 °C, respectively, using atomization feeding. The gas, liquid and solid products were determined by gas chromatography (GC), GC-mass spectrometry (MS) and Fourier transform infrared (FT-IR), and the gas, liquid and solid yield reached 7.0 wt.%, 89.0 wt.% and 0.1% wt.%, respectively, with an error of 3.9 wt.% at 500 °C. The pyrolysis of MR via microwave-assisted heating coupled with atomization feeding was found to be more efficient than the conventional pyrolysis process. In addition, the theoretical and actual heat for MAP of MR was 1461 kJ/kg and 2629 kJ/kg at 500 °C, respectively. The material balance and heat analysis results can be used to guide the design of an amplifying device.

Unprecedented alkylation of carboxylic acids by boron trifluoride etherate

The alkylation of carboxylic acids by an ethyl moiety of boron trifluoride etherate in the absence of ethyl alcohol from the reaction system is unexpected and novel. Both aromatic and aliphatic carboxylic acids were clearly alkylated affording good yields in short reaction times with the exception of nicotinic acid that necessitated an overnight reaction. It was noted that while ortho -substituted hydroxyl groups of carboxylic acids investigated were not affected by alkylation, those of meta - and para -substituted carboxylic acids were partially etherified. Furthermore, the alkylation reaction was found to be compatible with a range of functional groups such as halogens, amino and nitro groups except for the alkene function of undecylenic acid that underwent polymerisation with concomitant alkylation of its carboxylic acid function. KEY WORDS : Carboxylic acids, Alkylation, Etherification, Functional groups, Boron trifluoride etherate Bull. Chem. Soc. Ethiop. 2018 , 32(2), 387-392. DOI: https://dx.doi.org/10.4314/bcse.v32i2.16