Carbon Chain Length Of Alcohols Research Articles

Thermophysical and transport properties of binary mixtures containing triethylene glycol and alcohols at different temperatures

Densities and viscosities have been measured for the binary mixtures of triethylene glycol with + 2-propanol, 2-butanol and 2-pentanol over the entire range of mole fraction at T = 293.15–323.15 K. From experimental data, the excess molar volume, thermal expansion coefficient, excess thermal expansion coefficient and deviation in viscosity were calculated. The experimental results have been discussed in terms of molecular interactions and formation of molecular complexes between unlike molecules. Influence of temperature and carbon chain length of alcohols on mentioned properties was discussed. Moreover, the friction theory coupled with PC-SAFT equation of state was applied to produce the viscosities of pure data and binary mixtures.

Phase behaviors, fuel properties, and combustion characteristics of alcohol-vegetable oil-diesel microemulsion fuels

ABSTRACTBiofuels are being considered as alternatives to fossil-based fuels due to depletion of petroleum-based reserves and pollutant emission concerns. Vegetable oils and bioalcohols have proven to be viable alternative fuels both with and without engine modification. However, high viscosity and low energy content are long-term operational problems with vegetable oils and bioalcohols, respectively. Therefore, vegetable oil-based microemulsification is being evaluated as a method to reduce the high viscosity of vegetable oils and enhance the miscibility of alcohol and oil phases. Studies have shown that microemulsification with different alcohols lead to varying fuel properties depending on their structure. The overall goal of this study was to formulate microemulsion fuels with single and mixed alcohol systems by determining the effects of water content, alcohol branching structure and carbon chain length on phase behaviors, fuel properties, and emission characteristics. It was found that microemulsion fuels using certain alcohols displayed favorable stability, properties, and emission characteristics. Flames of fuels with linear short-chain-length alcohols had larger near-burner blue regions and lower CO and soot emissions indicating the occurrence of more complete combustion. In addition to alcohol effects, the effect of vegetable oils, surfactants, and additives on emission characteristics were insightful in pursuit of appropriate microemulsion fuels as cleaner burning alternatives to both No.2 diesel and canola biodiesel.

Alcohol-Assisted Water Condensation and Stabilization into Hydrophobic Mesoporosity

In this work, we report the condensation and stabilization of water vapors into water-repellent, methyl-functionalized, mesoporous, silica-based films at room temperature and atmospheric pressure using a soft alcohol-assisted method. The capillary pore fillings due to water adsorption were ensured by a fine control of partial vapor pressures of alcohol and water. A synergic coadsorption of alcohol and water was observed due to a reversible surface energy switching from hydrophobic to hydrophilic induced by the preferential interaction of the alkyl side of the surfactant alcohol molecules with the hydrophobic walls. The influences of the film mesoprosity as well as the type of the alcoholic coadsorbate (methanol, ethanol, and 1-propanol) were investigated, revealing various Kelvin’s law-like adsorption behaviors, depending on the alcohol carbon chain length. Interestingly, the stabilization of condensed domains of quasi-pure water phases was obtained in confined hydrophobic spaces by a presumed selective alcohol desorption. It was demonstrated that a small quantity of remaining Si–OH groups at the pore surface was sufficient to stabilize water nanodomains in hydrophobic pores. These results were based on in situ ellipsometric investigations, that further allowed measuring the wetting angle of water droplets trapped within the porous network, from which we could evaluate the quantity of polar −OH groups remaining in the methyl-functionalized, mesoporous, silica-based films. This first insight in alcohol/water coadsorption may open the door toward new generation of alcohol sensors.

Straightforward Enzyme-Catalyzed Asymmetric Synthesis of Caffeic Acid Esters in Enantioenriched Form

Enantiopure caffeic acid esters were successfully synthesized from caffeic acid and corresponding (R,S)-alcohol catalyzed by an immobilized lipase (Novozym 435) from Candida antarctica. Effects of the alcohol carbon chain length and the type of organic solvents were first investigated, and anhydrous isooctane was finally selected as the most suitable reaction medium. The optimal synthesis parameters for caffeic acid ester synthesis were evaluated using response surface methodology. The actual experimental conversions of 33.8 ± 1.8% and an E value of >100 for (R)-1-methylbutyl caffeate, achieved under optimized reaction conditions, indicated a good fit to the predictive model. Kinetic and thermodynamic analyses were conducted to determine the main factors affecting enantiomeric discrimination. Results from the batch reuse stability study show that the immobilized enzyme could be effectively reused. The present study is the first to use lipase as the chiral catalyst to prepare optically pure caffeic acid es...

Cosolvent effect on the aggregation of amphipathic highly branched diblock polyether in aqueous solution

An amphipathic highly branched diblock polyether, PA60-2-40, was synthesized via anion ring-opening polymerization of propylene oxide (PO) and ethylene oxide (EO), using phenol-amine resin (PA) as the initiator. The molecular structure was confirmed by FT-IR and 1H NMR. The surface tension and fluorescence spectroscopy measurements provide information about the effect of cosolvents on the critical micelle concentration (CMC) and the standard Gibbs energy (ΔGomic). The cosolvents have a significant effect on the CMC of PA60-2-40; the CMC first decreases and then increases with increasing content of n-pentanol, but with an increase of ethylene glycol concentration, there is durative decrease of the CMC. The micellization becomes more spontaneous in the presence of cosolvents with more hydroxyl groups, but the CMC does not monotonically increase or decrease with the increasing carbon chain length of aliphatic monohydric alcohols. The values of surface activity parameters (Гmax, Amin and ∆Gomic) calculated all coincide with the results of the experiment. Additionally, TEM and DLS demonstrate that the size of the micelles can be changed by the addition of alcohols, but the aggregation morphology will not change.

Butyric acid esterification kinetics over Amberlyst solid acid catalysts: The effect of alcohol carbon chain length

The liquid phase esterification of butyric acid with a series of linear and branched alcohols is examined. Four strong cation exchange resins, Amberlyst™ 15, Amberlyst™ 36, Amberlyst™ BD 20, and Amberlyst™ 70, were used along with para-toluenesulfonic acid as a homogeneous catalyst. The effect of increasing alcohol carbon chain length and branching on esterification rate at 60°C is presented. For all catalysts, the decrease in turnover frequency (TOF) with increasing carbon chain length of the alcohol is described in terms of steric hindrance, alcohol polarity, and hydroxyl group concentration. The kinetics of butyric acid esterification with 2-ethylhexanol using Amberlyst™ 70 catalyst is described with an activity-based, pseudo-homogeneous kinetic model that includes autocatalysis by butyric acid.

Excess molar volumes of 1,3 propanediol + (C1-C5) alkan-1-ols: Application of cubic EOS

Densities of the binary mixtures consist of methanol, ethanol, 1- propanol, 1-butanol and 1-pentanol with 1,3 Propanediol were measured at temperatures (293.15, 298.15, 303.15 and 313.15) K and atmospheric pressure. Measurements have been made over the full range of compositions and for the pure compounds by using a vibrating tube densimeter. Excess molar volumes have been obtained from these experimental results and were fitted to a Redlich-Kister type expansion. The results were interpreted in terms of molecular interactions and structural factors of the alcohols. It was observed that an increase of the alcohol carbon chain length led to lower interactions on mixing. The Peng-Robinson-Stryjek-Vera (PRSV) equation of state has been used to correlate the binary excess molar volumes.

Enzymatic lipophilisation of phenolic acids through esterification with fatty alcohols in organic solvents

We investigated and optimised the synthesis of lipophilized esters between selected phenolic acids and fatty alcohols in a binary solvent system, composed of hexane and butanone. The effect of proportions of hexane and butanone was first studied by varying the volume ratio of hexane/butanone from 85:15 to 45:55. It was found that the conversion of phenolic acids strongly depended on the proportions of hexane and butanone. To examine the effect of carbon chain length of fatty alcohols on the reaction rate, the esterifications of C4–C18 straight-chain fatty alcohol with dihydrocaffeic acid (DHCA), as a model phenolic acid, were systematically evaluated. The results indicated that the conversion of DHCA was significantly affected by the number of carbon chain of fatty alcohols. Roughly 95% conversion was achieved within 3days when hexanol was used as an acyl acceptor; while only 56% and 44% conversions were achieved when 1-butanol and octadecanol were employed, respectively. However, the conversions of ferulic and caffeic acids under the same conditions were much lower than was that of DHCA. The optimal mixture ratio of hexane to butanone was found to be 65:35. Using the reaction of octanol and DHCA as a model, the reaction parameters, such as temperature, enzyme load, reaction time and substrate molar ratio, were optimised with response surface methodology (RSM). A second polynomial model was generated and optimised reaction conditions were obtained as: temperature 60°C, reaction time 3.9days, enzyme load 238mg, and substrate molar ratio 3.6 (octanol/DHCA). A validation reaction, based on the optimal conditions, was conducted, to yield 94.5% conversion of DHCA, indicating the suitability of the RSM model.

Mineral Oil and Aliphatic Alcohols: Toxicity and Analysis of Synergistic Effects on German Cockroaches (Dictyoptera: Blattellidae)

Two mineral oils and 12 linear primary alcohols were studied, alone and in combination, to determine their contact toxicity to adult German cockroaches, Blattella germanica (L.) (Dictyoptera: Blattellidae). The more toxic oil, PD23 (LD50 = 1.45 mg per cockroach) was used for combination studies. Alcohols with carbon chain lengths of C3 and C8 through C12 were the most toxic, with LD50 values ranging from 0.3 to 0.6 mg. C1 (methanol) and C14 (1-tetradecanol) were least toxic, with LD50 values of 2.35 and 1.75 mg, respectively. Eight of the 12 combinations of a nonlethal dose of PD23 oil with an LD10 dose of alcohol produced significantly greater mortality than predicted under the assumption of additive effects. A sample of five synergistic oil + alcohol combinations, covering most of the alcohol carbon chain length range over which synergy occurred, was further studied by calculating LD50 values for three fixed mixture ratios (80:20, 50:50, and 20:80) of each combination. Results were analyzed using both graphical techniques (isobole analysis) and by nonlinear regression. At least one, but not necessarily all, of the three fixed ratio combinations of each oil + alcohol pairing indicated synergy. The conclusions drawn from the isobole and regression analyses were consistent.

Synthesis of short chain alkyl esters using cutinase from Burkholderia cepacia NRRL B2320

Short chain alkyl esters are well appreciated for fruity flavors they provide. These are mainly applied to the fruit-flavored products like jam, jelly, beverages, wine and dairy. Cutinase from Burkholderia cepacia NRRL B 2320 was found to be active in catalyzing the synthesis of alkyl esters in organic solvent. The optimal temperature range for the enzyme catalyzed synthesis was found to be from 35 °C to 40 °C. The maximum conversion (%) during synthesis of ester was obtained for butyric acid (C4) and valeric acid (C5) with butanol reflecting the specificity of the enzyme for short-chain length fatty acids. In case of alcohol specificity, butanol was found to be most preferred substrate by the enzyme and conversion (%) decreased with increasing carbon chain length of alcohol used in the esterification reaction. The kinetic analysis for the synthesis of butyl butyrate by varying concentration of one substrate at a time (butanol or butyric acid), showed that Ping–Pong Bi Bi model with acid inhibition and influence of initial water is most suitable model for the prediction of the reaction kinetics.

Density and Excess Molar Volume of the Protic Ionic Liquid Bis(2-hydroxyethyl)ammonium Acetate with Alcohols

Densities were determined for binary mixtures containing the protic ionic liquid bis(2-hydroxyethyl)ammonium acetate [BHEAA] and an alcohol (methanol, ethanol, and 1-propanol) at four different temperatures (293.15, 303.15, 313.15, and 323.15) K and ambient pressure. Coefficients of thermal expansion and excess molar volumes were calculated from the experimental densities. The excess molar volumes were fitted using the Redlich-Kister polynomial equation. Negative deviations from ideal behavior of the excess molar volume were observed for all systems investigated in this study. The results were interpreted in terms of ion-dipole interactions and structural factors of the ionic liquid and alcohol. It was observed that an increase of the alcohol carbon chain length led to lower interactions on mixing.

ELISA assays and alcohol: increasing carbon chain length can interfere with detection of cytokines

Enzyme-linked immunosorbent assays (ELISAs) are frequently used in studies on cytokine production in response to treatment of cell cultures or laboratory animals. When an ELISA assay is performed on cell culture supernatants, samples often contain the treatment agents. The purpose of the present study was to determine if some of the agents evaluated might inhibit cytokine detection by interfering with the ELISA, leaving the question of whether cytokine production was inhibited unanswered. Mouse and human cytokine ELISA kits from BD Biosciences were used according to the manufacturer’s instructions. Cytokine proteins were subjected to one to five carbon alcohols at 86.8 mM (methanol, ethanol, 1-propanol, 2-propanol, n-butanol, and n-pentanol). After treating cell cultures with alcohols of different carbon chain lengths, we found that some of the alcohols interfered with measurement of some cytokines by ELISA, thus making their effects on cytokine production by cells in culture unclear. Increasing carbon chain length of straight chain alcohols positively correlated with their ability to inhibit detection of tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10), but not with the detection of interleukin 6 (IL-6), interleukin 8, (IL-8), and interleukin 12 (IL-12). To avoid misinterpretation of treatment effects, ELISA assays should be tested with the reference protein and the treatment agent first, before testing biological samples. These results along with other recent results we obtained using circular dichroism indicate that alcohols with two or more carbons can directly alter protein conformation enough to disrupt binding in an ELISA (shown in the present study) or to inhibit ligand-induced conformational changes (results not shown). Such direct effects have not been given enough consideration as a mechanism of ethanol action in the immune system.

Effect of carbon chain length of cosurfactant on the rheological properties of nonionic wormlike micellar solutions formed by a sugar surfactant and monohydroxy alcohols

The effect of carbon chain length of monohydroxy alcohols on the rheological properties of micellar solutions formed in water/sucrose monohexadecanoate (C 16SE)/monohydroxy alcohol systems (C 3–C 9) was studied. By adding alcohols in the aqueous C 16SE solution, the zero-shear viscosity increases, and then decreases after a maximum for all the systems except for the 1-propanol system. The maximum η 0 increases with the chain length of the alcohol. The oscillatory-shear behavior of the viscous samples can be described by the Maxwell model which is typically observed for wormlike micellar solutions. The plateau modulus ( G 0) related to the number of entanglements between wormlike micelles increases monotonously and G 0 is higher for longer-chain alcohol systems except for the nonanol system, indicating more dense network is formed. The relaxation time ( τ R ) related to the micellar length increases and then decreases with weight fraction of alcohol. It indicates a faster stress relaxation model other than Maxwell model at high alcohol content due to the formation of branched micelles. Longer carbon chain length of alcohol gives higher maximum τ R . The weight fraction of alcohol at which the maximum τ R appears almost corresponds to that for η 0.

Precipitation of Nanocrystalline CeO2 Using Triethanolamine

Synthesis of cerium oxide nanocrystallites via precipitation using triethanolamine is reported. The molecular water associated with the cerium nitrate precursor is exploited to generate hydroxyl ions with the help of triethanolamine, facilitating precipitation. The small crystallite diameter (3 nm) in the as prepared powder is believed to result from the limited amount of water present. Solvent type has no effect on the final crystallite size or structure; however, it plays an important role in the dispersion of the nanoparticles with dispersity of the particles increasing with increasing carbon chain length of the solvent alcohol used.

Silica Thin-Layer Chromatographic Studies of Surfactants with Mixed Aqueous-Organic Eluents Containing Thiourea: Simultaneous Separation of Co-existing Cetyltrimethylammonium Bromide, Dodecyltrimethylammonium Bromide, and Polyoxyethylene (20) Sorbitan Monolaurate

Silica thin-layer chromatography of three surfactants using various solvent systems is described. The mutual separation of coexisting cetyltrimethylammonium bromide (CTAB), dodecyltrimethyl-ammonium bromide (DTAB), and polyoxyethylene (20) sorbitan monolaurate (Tween 20) is achieved on silica layer using 5% aqueous thiourea-acetone-methanol (60:20:20,v/v/v) as the mobile phase. The effect of the carbon chain length of alcohols (methanol, ethanol, n-propanol, and n-butanol) on the mobility of these surfactants is examined on silica layers. The comparative study is performed with sulfur- (thiourea) and oxygen- (urea) containing compounds in the eluent on the mobility as well as on the separation of co-existing CTAB, DTAB, and Tween 20. The interference on the resolution of the mixture of CTAB, DTAB, and Tween 20, due to presence of metal cations as impurities, is also examined. The limits of detection of CTAB, DTAB, and Tween 20 are estimated.

Variables Affecting the Induction Period during Acid-Catalyzed Transesterification of Canola Oil to FAME

Experiments were conducted at ambient temperature to study mass transfer limitations, indicated by the presence of a triglyceride (TG) induction period, during the acid-catalyzed transesterification reaction. The effects of the water and free fatty acid (FFA) content, the molar ratio of alcohol to oil, and the alcohol type on the TG induction period were examined. Experimental results showed that the TG induction period (i) decreased with a decrease in the water concentration, (ii) decreased with an increase in the methanol (MeOH)-to-oil molar ratio for a dispersed nonpolar−TG phase and continuous polar−MeOH phase, (iii) decreased with an increase in the alcohol carbon chain length, and (iv) increased with an increase in the FFA concentration. The addition of fatty acid methyl esters (FAMEs) to the reaction mixture was proposed as a strategy to decrease the TG induction period.

Effects of Alcohols and Counterions on the Phase Behavior of 1-Octyl-3-methylimidazolium Chloride Aqueous Solution

Phase behavior of ternary systems involving 1-octyl-3-methylimidazolium chloride ([C8mim]Cl), water, and different alcohols (1-hexanol, 1-octanol, 1-decanol, and 1-dodecanol) is investigated at 25 degrees C. With the use of polarized optical microscopy and small-angle X-ray scattering techniques, lyotropic lamellar phases (Lalpha) are identified in all systems, the formation of which is considered as a synergetic result of the hydrophobic force and the hydrogen-bonded network comprising an imidazolium ring, Cl-, water, and alcohols. In these Lalpha phases, alcohol molecules play important roles not only because they could partly penetrate into the palisade layer with their hydroxyl groups extruded to form the network at the aggregate interface, but also because they could partly locate themselves in the interior of the hydrophobic bilayers to twist with the alkyl chains of [C8mim]Cl. Influencing factors such as the carbon chain length and content of different alcohols on these Lalpha phases are discussed. With comparison to analogous ternary systems of [C8mim]BF4 and [C8mim]PF6, it is found that the strong interaction between counterions and alcohols favors the appearance of ordered assemblies.

Rheological and tribological characteristics of the synthesized lubricants derived from vegetable oils

The double bonds in the vegetable oils can be conjungated and Diels-Alder react when they are heated in the existence of the catalyst. The percent of the double bond will decrease and the oxidative stability of the vegetable oils can be ameliorated. Dimmer acid can react with different carbon chain length of alcohols to form dimmer acid esters. A series of dimmer acid esters were synthesized and their rheological characteristics (viscosity, viscosity index, pour point) and tribological characteristics (the coefficient of friction at different load, the characteristic of extreme pressure (PB), the wear scare diameter (D30 min196 N) were evaluated and analyzed. The results showed that the characteristics of Di-iso-octanol dimmer acid ester were the best among the synthesized dimmer esters. It’s a lubricant with good properties (the viscosity is 94.5 mm2/s, the viscosity index is high up to 141 and the pour point is −49t). It is a kind of newly interesting ester type lubricant. Its rheological and tribological characteristics are even better than those of the slap-up synthesized lubricant-pentaerythritol esters (C7–9 acidate). The FT-IR spectrophotometer was used to analyze the structure of the synthetic esters. Their IR spectra are the same as the typical IR spectrum of ester. The test indicated that Di-iso-octanol dimmer acid ester could be used as a kind of base lubricant with excellent quantity.

Homogeneous nucleation rates of higher n-alcohols measured in a laminar flow diffusion chamber.

Nucleation rate isotherms of n-butanol, n-pentanol, n-hexanol, n-heptanol, and n-octanol were measured in a laminar flow diffusion chamber using helium as carrier gas. The measurements were made at 250-310 K, corresponding to reduced temperatures of 0.43-0.50, and at atmospheric pressure. Experimental nucleation rate range was from 10(3) to 10(7) cm(-3) s(-1). The expression and accuracy of thermodynamic parameters, in particular equilibrium vapor pressure, were found to have a significant effect on calculated nucleation rates. The results were compared to the classical nucleation theory (CNT), the self-consistency corrected classical theory (SCC) and the Hale's scaled model of the CNT. The average ratio between the experimental and theoretical nucleation rates for all alcohols used was 1.5x10(3) when the CNT was used, and 0.2x10(-1) when the SCC was used and 0.7x10(-1) when the Hale's scaled theory was used. The average values represent all the alcohols used at the same reduced temperatures. The average ratio was about the same throughout the temperature range, although J(exp)/J(the) calculated with the Hale's scaled theory increased slightly with increasing temperature. The saturation ratio dependency was predicted closest to experiment with the classical nucleation theory. The nucleation rates were compared to those found in the literature. The measurements were in reasonable agreement with each other. The molecular content of critical alcohol clusters was between 35 and 80 molecules. At a fixed reduced temperature, the number of molecules in a critical cluster decreased as a function of alcohol carbon chain length. The number of molecules in critical clusters was compared to those predicted by the Kelvin equation. The theory predicted the critical cluster sizes well.

Ester Synthesis Catalyzed by <I>Mucor miehei</I> Lipase Immobilized on Magnetic Polysiloxane–Polyvinyl Alcohol Particles

Mucor miehei lipase was immobilized on magnetic polysiloxane-polyvinyl alcohol particles by covalent binding with high activity recovered. The performance of the resulting immobilized biocatalyst was evaluated in the synthesis of flavor esters using heptane as solvent. The impact on reaction rate was determined for enzyme concentration, molar ratio of the reactants, carbon chain length of the reactants, and alcohol structure. Ester synthesis was maximized for substrates containing excess acyl donor and lipase loading of 25 mg/mL. The biocatalyst selectivity for the carbon chain length was found to be different concerning the organic acids and alcohols. High reaction rates were achieved for organic acids with 8 or 10 carbons, whereas increasing the alcohol carbon chain length from 4 to 8 carbons gave much lower esterification yields. Optimal reaction rate was determined for the synthesis of butyl caprylate (12 carbons). Esterification performance was also dependent on the alcohol structure, with maximum activity occurring for primary alcohol. Secondary and tertiary alcohols decreased the reaction rates by more than 40%.