Aliphatic Monocarboxylic Acids Research Articles

Esters of 1,1,1-trimethylolpropane as a base and component of lubricating oils

Symmetrical, unsymmetrical esters of 1,1,1-trimetilolpropan (TMP) with C6-C8 aliphatic monocarboxylic acids have been synthesized. Their physicochemical, viscosity-temperature, thermal-oxidative (TOS) properties have been studied. It was found that esters have relatively low viscosities at 100 oC (3.55–4.39 mm2/s), high flash points (198–220 oC) and viscosity index (110–121 units), low freezing temperature (minus 50 oC ÷ minus 58 oС) and viscosity at – 40 oС (2800–3310 mm2/s). Also, the esters are distinguished by high thermal and oxidative stability: low volatility – 0.18–0.40 wt %, sediment amount – 0.18–0.32 wt %, viscosity increase at 100 oC – 0.0031–0.0042 %. The dependence between the chemical structure and performance characteristics of the obtained compounds was also studied. It was found that these esters meet requirements for low-viscosity aviation oils and are proposed as the basis and component of new oils.

Сложные эфиры оксипропилированного 2,2,6,6-тетраметилолциклогексанола в качестве основы и компонента высокотемпературных смазочных масел

The esters of oxypropylated 2,2,6,6-tetrametylolcyclohexanol with aliphatic monocarboxylic acids C -C4 8have been synthesized. Their physicochemical, viscosity-temperature, thermal-oxidative and lubricating propertieswere studied. It was determined that they have good operational properties, they meet requirementsfor high-temperature lubricating oils and are recomended as the new base or components to other lubricating oils.

Синтез сложных эфиров оксипропилированного 2,2,5,5-тетраметилолциклопентанола и исследование их в качестве перспективных смазочных материалов

At present, with the development of modern technology, the requirements for lubricating oils, especially their viscosity-temperature, thermo-oxidative and lubricating characteristics, are becoming more stringent. In this aspect, the synthesis and study of esters of oxypropylated 2,2,5,5-tetramethylolcyclopentanol (TMCP) with cyclic fragments, active centers, multipolar ester groups is promising, have a certain scientific and practical significance.The esters were synthesized by the esterification reaction of oxypropylated TMCP with aliphatic monocarboxylic acids C4-C8, and their physicochemical, viscosity-temperature, thermal-oxidative and lubricating properties were studied. After determining the viscosity-temperature properties, it was established that they have a low pour point (minus 38-minus 430C), an average viscosity at 1000C (ν100 = 23.50-40.22 mm2/s), a high viscosity index (133-150 units) and flash point (305-3800C). When determining the thermo-oxidative stability of esters, it was found that they have low acid numbers after oxidation (2.51-3.28 mg KOH/g), corrosion of electrodes AK-4 (0.06-0.16 mg/cm2), ШХ -15 (0.08-0.11 mg/cm2) and the precipitate is insoluble in isooctane is low (0.120-0.248% of the mass), the volatility is 0.30-0.50% of the mass. The lubricating properties of esters were also determined: critical load Рк,Н = 750-900, spot wear diameter Di,mm at Р = 196Н = 0.50-0.65. Oxypropylated esters in comparison with reference esters - TMCP ester with caproic acid and pentaerythritol ester (PET) and mixture of fatty acids (MFA) fr. C5-C6 surpass them in almost all parameters, are higher molecular weight and promising, and this makes it possible to create on their basis high-temperature lubricating oils special purpose, components or additives to other lubricating oils.

Vapor- and aerosol-phase atmospheric organic matter in urban air of the Midwest USA

Vapor- and aerosol-phase atmospheric organic matter were collected in East St. Louis, MO using the high-volume sampling method. Samples were processed by traditional analytical methods and analyzed by multidimensional gas chromatography with time-of-flight mass spectrometric detection. Levels of identified, hydrocarbon-like organic vapor and aerosol species (i.e., HOV and HOA, respectively) were 10–42 ng m−3 and 0.020–3.6 ng m−3, respectively. Concentrations of identified, oxygenated organic vapor and aerosol species (i.e., OOV and OOA, respectively) were 2–66 ng m−3 and 23–310 ng m−3, respectively. The principal feature of the HOV was an unresolved complex mixture that represented 54.5 ± 11.3% of the total HOVs during the field campaign. Levels of n- and branched alkanes, alkyl and cycloalkylbenzenes, polyaromatic hydrocarbons (PAHs), and alkyl-substituted PAHs generally declined from the morning rush hour to the 1000–1400 sampling period, which was similar to the expected trend in reactivity with respect to OH. The OOV included aliphatic mono-carboxylic acids, aliphatic and aromatic alcohols, aldehydes, and ketones, and alicyclic ketones, alcohols, and epoxides (i.e., montoterpenoids). The bulk of the OA species (∼99%) were a complex mixture of OOA, which included multifunctional n-aliphatic, alicyclic, and aromatic hydrocarbons, dicarboxylic and ketocarboxylic aliphatic and dicarboxylic monoaromatic acids, lactones, tetrols, and pentitols. The sampling and analytic techniques provided quantitative molecular information for HOVs in ambient air, which are a missing source of secondary organic aerosol precursors. Molecular characterization and quantitation of HOVs and OOA species will facilitate predictions of SOA formation using molecular-specific models.

Effect of the Polymer Structure Diversity on the Eddies Suppression of Basrah Light Crude Oil Turbulent Flow

Poly(pentaerythritol adipate), poly(pentaerythritol sebacate), and poly(pentaerythritol hexadecandioate) derivatives containing different length alkyl branches were synthesized by two subsequent steps; the reaction of pentaerythritol with (C8-C16) linear aliphatic monocarboxylic acids and then, polymerization of products with (C6-C16) linear aliphatic dicarboxylic acids, using 1% para toluene sulfonic acid as a catalyst. The products were purified and characterized by FTIR, 1H NMR, and 13C NMR spectroscopy. End group analysis was also used as a molecular weight determination technique. The drag-reducing properties of those polymers were investigated in the turbulent flow of Basrah light crude oil using a closed-loop circulation system. Some were found to perform very well DRA and drag reduction efficacy of polymer was further found to be dependent on flowrate, polymer concentration, medium-temperature, and its chemical structure. Also, the effect of the imposed mechanical shear on the polymer stability as a function of time has been investigated using a cylindrical rotator device. It was observed that distance between branch points plays a direct role in contributing to the polymer performance and its mechanical stability.

Effect of leucine on the activation energy of the corrosion process of St3 steel in 0,04% CH3COOH solution – kerosene system

In this investigation we studied the temperature dependence of the protection effect of St3 steel against corrosion in 0,04% CH3COOH solution-kerosene system by gravimetric method of leucine (derivative of aliphatic monoamino monocarboxylic acids – AL-MAMCA: with the general formula CH3-CH(CH3)-CH2-CH(NH2)-COOH). Previously at 20 ºC we investigated this corrosion process in various two-phase acid and neutral electrolyte solutions in hydrocarbon systems and revealed a good protection effect of leucine. On the basis of the obtained data, the activation energy in the corrosion process of St3 steel has been calculated without and in the presence of the leucine in the aggressive system shown by analytical and graphical methods (graph of dependence of lgK on 1/T). It was found that the addition of leucine to the aggressive system in terms of corrosion causes a significant increase in the activation energy of St3 steel in the corrosion process, and thus complicates the process of this undesirable process. It has been shown that in parallel with the increase in the temperature of the aggressive environment in terms of corrosion, the previously physically adsorbed leucine molecules on the surface of St3 steel are gradually replaced by chemically adsorbed ones, thus further strengthening the metal – inhibitor bond.

Conductivity Properties of Selected Aliphatic Monocarboxylic Acid Anions in Water at 298.15 K

Conductivity Properties of Selected Aliphatic Monocarboxylic Acid Anions in Water at 298.15 K

Extraction of Monocarboxylic Acids from Diluted Solutions with Polyethylene Glycol

An aqueous two-phase system based on polyethylene glycol-1500 and sodium sulfate for the extraction of a number of monocarboxylic acids from aqueous solutions has been studied. The influence of the phase contact time, system composition, the molecular weight of the polymer, and temperature on the quantitative characteristics of the interphase distribution of a number of aliphatic monocarboxylic acids has been investigated. Based on the results, it is concluded that these systems are effective for solving problems of the extraction, separation, and purification of carboxylic acids and they are promising as extraction systems for the extraction of metal salts in the presence of carboxylic acids.

A one year study of functionalised medium-chain carboxylic acids in atmospheric particles at a rural site in Germany revealing seasonal trends and possible sources

This study presents a yearlong data set of 28 medium-chain functionalised carboxylic acids (C5 to C10) in atmospheric aerosol particles (PM10) from a German rural measurement station, which is analysed to obtain seasonal trends and evidences for possible sources of these rarely studied compounds. The analysed carboxylic acids were divided into four main groups: (I) functionalised aliphatic monocarboxylic acids, (II) functionalised aromatic monocarboxylic acids, (III) non-functionalised and functionalised aliphatic dicarboxylic acids, and (IV) aromatic dicarboxylic acids. A concentration maximum in summer was observed for aliphatic carboxylic acids, indicating mainly photochemical formation processes. For example, the highest mean summer concentrations were observed for 4-oxopentanoic acid (4.1 ng m−3) in group I and for adipic acid (10.3 ng m−3) in group III. In contrast, a concentration maximum in winter occurred for aromatic carboxylic acids, hinting at anthropogenic sources like residential heating. The highest mean winter concentrations were observed for 4-hydroxybenzoic acid (2.4 ng m−3) in group II and for phthalic acid (5.8 ng m−3) in group IV. For the annual mean concentrations, highest values were found for adipic acid and 4-oxopimelic acids with 7.8 ng m−3 and 6.1 ng m−3, respectively. The concentrations of oxodicarboxylic acids exceeded those of their corresponding unsubstituted form. Accordingly, straight-chain dicarboxylic acids might act as precursor compounds for their respective oxygenated forms. Similarly, unsubstituted monocarboxylic acids are possible precursors for functionalised aliphatic monocarboxylic acids. The present study contributes to the speciation of organic content on a molecular level of atmospheric particles, as well as giving hints for possible sources for these carboxylic acids.

Molecular Distribution, 13C-Isotope, and Enantiomeric Compositions of Carbonaceous Chondrite Monocarboxylic Acids.

The water-soluble organic compounds in carbonaceous chondrite meteorites constitute a record of the synthetic reactions occurring at the birth of the solar system and those taking place during parent body alteration and may have been important for the later origins and development of life on Earth. In this present work, we have developed a novel methodology for the simultaneous analysis of the molecular distribution, compound-specific δ13C and enantiomeric compositions of aliphatic monocarboxylic acids (MCA) extracted from the hot-water extracts of sixteen carbonaceous chondrites from CM, CR, CO, CV and CK groups. We observed high concentrations of meteoritic MCAs, with total carbon weight percentages which in some cases approached those of carbonates and insoluble organic matter. Moreover, we found that the concentration of MCAs in CR chondrites is higher than in the other meteorite groups, with acetic acid exhibiting the highest concentration in all samples. The abundance of MCAs decreased with increasing molecular weight and with increasing aqueous and/or thermal alteration experienced by the meteorite sample. The δ13C isotopic values of MCAs ranged from -52 to +27‰, and aside from an inverse relationship between δ13C value and carbon straight-chain length for C3-C6 MCAs in Murchison, the 13C-isotopic values did not correlate with the number of carbon atoms per molecule. We also observed racemic compositions of 2-methylbutanoic acid in CM and CR chondrites. We used this novel analytical protocol and collective data to shed new light on the prebiotic origins of chondritic MCAs.

Hydrothermal Decomposition of Amino Acids and Origins of Prebiotic Meteoritic Organic Compounds.

The organic compounds found in carbonaceous chondrite meteorites provide insight into primordial solar system chemistry. Evaluating the formation and decomposition mechanisms of meteoritic amino acids may aid our understanding of the origins of life and homochirality on Earth. The amino acid glycine is widespread in meteorites and other extraterrestrial environments; other amino acids, such as isovaline, are found with enantiomeric excesses in some meteorites. The relationship between meteoritic amino acids and other compounds with similar molecular structures, such as aliphatic monoamines and monocarboxylic acids is unclear; experimental results evaluating the decomposition of amino acids have produced inconclusive results about the preferred pathways, reaction intermediates, and if the conditions applied may be compatible with those occurring inside meteoritic parent bodies. In this work, we performed extensive tandem metadynamics, umbrella sampling, and committor analysis to simulate the neutral mild hydrothermal decomposition mechanisms of glycine and isovaline and put them into context for the origins of meteoritic organic compounds. Our ab initio simulations aimed to determine free energy profiles and decomposition pathways for glycine and isovaline. We found that under our modeled conditions, methylammonium, glycolic acid, and sec-butylamine are the most likely decomposition products. These results suggest that meteoritic aliphatic monocarboxylic acids are not produced from decomposition of meteoritic amino acids. Our results also indicate that the decomposition of L-isovaline prefers an enantioselective pathway resulting in the production of (S)-sec-butylamine.

Gas chromatographic-mass spectrometric investigation of n-alkanes and carboxylic acids in bottom sediments of the northern Caspian Sea

Abstract Prior to the start of experimental oil production in the Kashagan field (northern part of the Caspian Sea), n-alkanes and carboxylic acids contained in samples obtained from bottom sediments in the area of artificial island “D” were investigated by gas chromatography–mass spectrometry. Concentrations of 10 n-alkanes (composed of C10-C13, C15-C20) and 11 carboxylic acids (composed of C6-C12, C14-C16) were identified and measured. Concentrations of individual alkanes and carboxylic acids in bottom sediments of the various samples varied between 0.001 ÷ 0.88 μg/g and 0.001 ÷ 1.94 μg/g, respectively. Mass spectra, in particular the M+ molecular ion peak and the most intense peaks of fragment ions, are given. The present study illustrates the stability of molecular ions to electronic ionisation and the main fragment ions to the total ion current and shows that the initial fragmentation of alkanes implies radical cleavage of C2H5 rather than CH3. All aliphatic monocarboxylic acids studied were characterised by McLafferty rearrangement leading to the formation of F4 cation-radical with m/z 60 and F3 cation-radical with m/z 88 in the case of ethylhexanoic acid. The formation of oxonium ions presents another important aspect of acid fragmentation. Using mass numbers of oxonium ions and rearrangement ions allows determination of the substitution character in α- and β- C atoms. The essence of our approach is to estimate the infiltration of hydrocarbon fluids from the enclosing formation into sea water, comprising an analysis of derivatives of organic compounds in bottom sediments. Thus, concentrations of derived organic molecules can serve as a basis for estimates of the depth at which hydrocarbon fluids leak, i.e., to serve as an auxiliary technique in the search for hydrocarbon deposits and to repair well leaks.

Optimization of reactive extraction of C1–C4 aliphatic monocarboxylic acids from aqueous solutions: modeling solvation effect with extended‐LSER, A‐UNIFAC and SPR

AbstractThis paper studies reactive extraction of formic (FA), acetic (AA), propionic (PA) and butyric (BA) acids from aqueous solutions by tri‐n‐butyl amine/diluent, with particular focus on proper optimization and modeling of extraction equilibria. The uptake capacities of amine/diluent and diluent alone approximate the following order: oleyl alcohol > octyl acetate > diisobutyl ketone and BA > PA > AA ≈ FA. An intrinsic optimization structure has been applied to the description of optimum extraction field of relevant systems, based on analyzing the variation profiles of separation ratio R and synergistic enhancement SE factors through the derivative variation method. We present new solvation molecular models extended‐linear solvation energy relation (e‐LSER), SPR1 and SPR2 (solvation probability relation), and an extension to group‐contribution approach A‐UNIFAC (Association‐UNIFAC). A‐UNIFAC predicts phase equilibria using new group interaction parameters regressed from vapor‐liquid equilibrium data. The e‐LSER model involves eight descriptors used for expressing solvent effects. By performing SPR1 and SPR2, we are able to scale up the probability range and activation energy of solvation effect. The strength of acid‐amine association is calculated with chemodel. e‐LSER, A‐UNIFAC, SPR and chemodel simulate accurately the observed performance with average deviations inferior to 4.8%, 24.1%, 0.8% and 16.2%, respectively. © 2017 Curtin University and John Wiley & Sons, Ltd.

Hydrothermal carbon nanosphere-based agglomerated anion exchanger for ion chromatography

This work reports the application of hydrothermal carbon nanospheres (HCNSs) as stationary phases in ion chromatography. HCNSs were facilely quaternized through polycondensation of methylamine and 1,4-butanediol diglycidyl ether. The quaternization was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Owing to the electrostatic interaction, quaternized HCNSs were equably attached onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to construct the anion exchangers. The aggregation was verified by scanning electron microscopy and elemental analysis. Common anions, aliphatic monocarboxylic acids, polarizable anions, and aromatic acids were well separated on the stationary phases with good stability and symmetry. The prepared column was further applied to detect phosphate content in Cola drink samples. The limit of detection (S/N=3) was 0.09mg/L, and the relative standard deviation (n=10) of retention time was 0.31%. The average recovery was 99.58%.

Structural features of two polymorphs of ammonium uranyl crotonate

X-ray crystallography, FTIR spectroscopy and thermal analysis were conducted for crystals of two polymorphs of NH4UO2(C3H5COO)3, which are the first examples of uranyl tricarboxylate complexes with ions of unsaturated aliphatic monocarboxylic acid. The main structural units of both polymorphs are anionic complexes [UO2(C3H5COO)3]−. Uranium atoms adopt hexagonal bipyramidal coordination polyhedron, and crotonate ions realize bidentate cyclic type of coordination. Due to different packing of ammonium ions and [UO2(C3H5COO)3]− complexes triclinic crystals of α-polymorph have layer structure and cubic crystals of β-polymorph have three dimensional structure. Features of three dimensional packing of R+ ions and [UO2L3]− complexes in structures of 25 known R[UO2L3] compounds are discussed.

Synthesis and Study of Diesters of 1,2-Dimethyl Cyclohex-4-ene as Lubricating Oils

Several diesters of 1,2-dimethyl cyclohex-4-ene with C4–C9 aliphatic monocarboxylic acids and with C5–C9 synthetic fatty acids are synthesized. The physicochemical and performance properties of these compounds are studied and some of them are proposed as the parent for getting low-viscosity lubricating oils.

A Method for Esterification Reaction Rate Prediction of Aliphatic Monocarboxylic Acids with Primary Alcohols in 1,4‐Dioxane Based on Two Parametrical Taft Equation

ABSTRACTEsterification reaction rates of aliphatic monocarboxylic acids with primary alcohols in 1,4‐dioxane as inert solvent were investigated. Acids were esterified with 1‐propanol and alcohols with acetic acid as model reactants at a constant temperature of 60°C, at a fixed ionic strength and pH in a batch reactor with a constant volume. For evaluation of reaction rates, an exact kinetic equation for the equilibrium reaction was applied. Under these conditions and for low reactants, concentrations reaction rate depends only on the structure of reactants and, therefore, can be predicted by a correlation equation with two Taft coefficients (inductive and steric effects). From these equations, it is possible to estimate the esterification reaction rate constant for other acid‐alcohol pairs. This methodology may also be suitable for other kinetic systems measured under comparable experimental conditions.

Amphiphilic conjugates of β-cyclodextrin with acetylsalicylic and 2-(4-isobutylphenyl)propionic acids

New amphiphilic β-cyclodextrin derivatives containing pharmacologically important aromatic and aliphatic monocarboxylic acid fragments at both primary and secondary hydroxy groups were synthesized with the use of palmitic, acetylsalicylic, and 2-(4-isobutylphenyl)propionic acid chlorides. The position of the acyl groups in the carbohydrate fragments of β-cyclodextrin was determined by 13C NMR spectroscopy.

Theoretical Model for the Carboxylic Group Acidity Constant Based on Connectivity Index 3χv

Abstract We developed a regression model for prediction of COOH acidity constant on 19 amino and 16 aliphatic monocarboxylic acids. As variables we employed two subsummations of 3χv index terms, 3χv(chain) and 3χv(side). The calculation of 3χv(chain) includes only atoms constituting the main chain in a molecule, whereas the calculation of 3χv(side) includes atoms from the side chains. The model yielded r = 0.998, S.E. = 0.053 and r = 0.974, S.E. = 0.017, for amino and aliphatic monocarboxylic acids, respectively. As a test set we used three amino acids, valine, leucine, and isoleucine, predicting their pKa values with root-mean-square error, rms = 0.07 (I = 0) and 0.10 (I = 0.1 mol kg−1).

Antitumor Activity of Magnetite Nanoparticles: Influence of Hydrocarbonated Chain of Saturated Aliphatic Monocarboxylic Acids

Nanomaterial drug delivery systems are promising vehicles to improve chemotherapy and decrease side effects. In the last years, there have been more reports published in prestigious journals addressing the successful application of magnetite nanoparticles in tumors treatment. The antitumor effect of magnetic fluids was studied intensely by applying an external magnetic field to retain the nanoparticles in the tumor tissue, and also to help regulating the release of loaded drugs. These features make them more competitive as a drug carrier than other nanomaterials. In addition, the MRI (magnetic resonance imaging) property of magnetic nanomaterials can enhance the monitoring of drug carriers locations. In all cases, the tumor significantly regressed in size and the microscopic exam revealed that the tumor cells massively endocytosed magnetic nanoparticles and entered in lysis process. Although the functionalization of nanoparticles generally refers to the addition of a polar shell to increase their solubility on the human body liquids, we have demonstrated that nanomaterials based magnetite functionalized with different types of fatty acids could exhibit antitumor properties without applying any external alternating magnetic field, when tested in vitro, on HEp–2 cells. Keywords: Fatty acids, anti–tumor, cancer therapy, core@shell, nanofluids.