Alkyl Acetates Research Articles

Volumetric and Ultrasonic Studies of Molecular Interactions in n-Alkoxypropanols + Alkyl Acetates Mixtures at Different Temperatures

Densities and ultrasonic velocities have been measured over the whole composition range for the binary liquid mixtures of dipropylene glycol monomethyl ether (mixture of isomers) {CH3(OC3H6)2OH}, dipropylene glycol monopropyl ether (mixture of isomers) {CH3(CH2)2(OC3H6)2OH}, and dipropylene glycol monobutyl ether (mixture of isomers){CH3(CH2)3(OC3H6)2OH} with alkyl acetates using an Anton Paar DSA 5000 density and speed sound analyzer in the temperature interval (288.15 to 308.15) K and atmospheric pressure. From these experimental data, excess molar volume, VmE and deviations in isentropic compressibility, ΔκS, have been calculated. The computed results of these quantities have been correlated using the Redlich–Kister polynomial equation to obtain the binary coefficients and standard deviations.

Influence of the blend composition on the properties and separation performance of novel solvent resistant polyphenylsulfone/polyimide nanofiltration membranes

In this study, the preparation of novel solvent resistant nanofiltration membranes made of polyphenylsulfone (Radel-R® – PPSU) and polyimide (Matrimid®(MI)) in blends with three different compositions of PPSU/MI (75/25, 50/50, 25/75wt%) in NMP was investigated. Scanning electron microscopy (SEM) was used to investigate the morphological characteristics and the structure of asymmetric membranes. The prepared membranes had a typical asymmetric structure with a dense skin layer and a porous substructure. Macro-voids were observed in the membrane substructures for all compositions. The permeation of different organic solvents was measured for all prepared membranes in dead-end filtration cells. The flux of organic solvents through these membranes was found to depend directly on the blend composition. The highest flux for alcohol and alkanes was achieved for a 50/50wt% blend while for acetone and methyl ethyl ketone the highest permeability was measured for a 75/25wt% blend of PPSU/MI. A higher permeability of alkyl acetates was observed for the membrane made of 25/75wt% PPSU/MI. Solvent stability of the membranes has been tested by measuring the methanol permeability and Sudan II rejection before and after solvent treatment. Except for pure PPSU, all membranes were stable in the examined solvents. The results confirm that the membranes prepared from these blends are promising to be used for organic solvent nanofiltration. For better insight into the phase behaviour of the PPSU/MI blend, dense reference membranes were prepared by solution casting and solvent evaporation, followed by pure liquid sorption, differential scanning calorimetry and gas permeation measurements.

ChemInform Abstract: A Facile and Green Protocol for Nucleophilic Substitution Reactions of Sulfonate Esters by Recyclable Ionic Liquids [bmim][X

Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X–) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process ‘greener’.

Synthesis of 2,2,5,5‐Tetrasubstituted 1,4‐Dioxa‐2,5‐disilacyclohexanes via Organotin(IV)‐Catalyzed Transesterification of (Acetoxymethyl)alkoxysilanes

(Acetoxymethyl)silanes 2, 7a-c, and 10a-c with at least one alkoxy group, of the general formula (AcOCH2 )Si(OR)3-n(CH3)n (R: Me, Et, iPr; n=0, 1, 2), were synthesized from the corresponding (chloromethyl)silanes 1, 6a-c, and 9a-c by treatment with potassium acetate under phase-transfer-catalysis conditions. These compounds were found to provide 2,2,5,5-organo-substituted 1,4-dioxa-2,5-disilacyclohexanes 3, 8a-c, and 11a-c if treated with organotin(IV) catalysts such as dioctyltin oxide. The reaction proceeds through transesterification of the acetoxy and alkoxy units followed by ring-closure to form a dimeric six-membered ring. The corresponding alkyl acetates are formed as the reaction by-products. With these mild conditions, the method overcomes the drawbacks of previously reported synthetic routes to furnish 2,2,5,5-tetramethyl-1,4-dioxa-2,5-disilacyclohexane (3) and even allows the synthesis of 1,4-dioxa-2,5-disilacyclohexanes bearing hydrolytically labile alkoxy substituents at the silicon atom in good yields and high purity. These new materials were fully characterized by NMR spectroscopy, elemental analysis, mass spectrometry, and X-ray analysis (trans-8a).

Экстракционно-хроматографическое определение местных анестетиков в водных средах

The extraction novocaine, lidocaine anestezina are studied from aqueous media by individual organic solvents (aliphatic alcohols, normal and isomeric structure of C 3 – C 9 alkylacetates C 2 – C 5 ) and their mixtures using of different salting-out agents (chlorides, sulfates, sodium and ammonium). The coefficients of the distribution and the degree of extraction of anesthetics are calculated. It is shown that with increasing number of carbon atoms in the molecules of alcohols and esters their extractant possibility is decreased and alcohols isomers are less effective than normal ones. For the most complete extraction of the anesthetics the mixtures of alcohols with isomeric structure and alkyl acetates are used. Two and ternary-component mobile phase at chromatography in thin layer are studied for separation of local anesthetics in the concentrates, the mobility coefficients of substances are calculated. Quantitative evaluation are carried out by application of specialized software. The separation coefficients of anesthetics are calculated. The technique of determination of analytes in aqueous media is developed. The results of the extraction- chromatographic determination of novocaine, lidocaine and anaesthesin in aqueous media are proved by method «introduced – found». The range of detectable concentrations is 0.1 – 1 mkg/sm 3 , detection limit is 0.02 mkg/sm 3 . The relative error of determination is less than 10 %. Keywords : local anesthetics, extraction, chromatography in a thin layer (Russian) DOI: http://dx.doi.org/10.15826/analitika.2013.17.4.013 Ia . I . Korenman , T . V . Chibisova , P . T . Sukhanov , M.V. Zybenko Federal State Budget Educational Institution of Higher Professional Education «Voronezh State University of Engineering Technologies» (FSBEI HPE «VSUET») , Voronezh, Russian Federation

Liquid–Liquid Test Reactions to Characterize Two-Phase Mixing in Microchannels

Multiphase flow is often found in chemical engineering, food processing, or analytical devices. First contacting and droplet generation as well as coalescence and redispersion are important for the flow characteristics. In all processes, the channel geometry, fluid properties, and flow velocity determine the flow regime, droplet size, and interfacial area. The hydrolysis of alkyl acetates in organic phase with sodium hydroxide NaOH in the aqueous phase is investigated as flexible test reaction for mass transfer and interfacial area determination. The alkyl group is chosen from ethyl, isopropyl, or n-butyl, which differ in water solubility, diffusivity, and rate constant, for adequate design of the characteristic time for mass transfer. The consumption of NaOH is used for calculation of specific area and related mass transfer coefficient. Different channel geometries are characterized and design considerations are derived.

Volumetric and Viscosity Properties for the Binary Mixtures of 1-Octyl-3-methylimidazolium Tetrafluoroborate with Butanone or Alkyl Acetates

In this work, densities and viscosities for the binary mixtures of 1-octyl-3-methylimidazolium tetrafluoroborate, [C8mim][BF4], with butanone, methyl acetate, ethyl acetate, propyl acetate and butyl acetate have been determined at 298.15 K. These data were used to calculate the excess molar volumes \( V_{m}^{\text{E}} \) and the viscosity deviations (lnη)E for the mixtures. It is shown that values of \( V_{m}^{\text{E}} \) are negative, while those of (lnη)E are positive in the whole concentration range. The \( V_{m}^{\text{E}} \) values show their minimum at the composition of xIL ≈ 0.3, and the (lnη)E values exhibit a maximum at the same mole fraction. For the binary systems, the absolute values of \( V_{m}^{\text{E}} \) decrease in the order: butanone > methyl acetate > ethyl acetate > propyl acetate > butyl acetate, whereas those of (lnη)E decrease in the order: methyl acetate > ethyl acetate > propyl acetate > butyl acetate > butanone. The results are discussed in terms of the ion–dipole interactions between cations of the ionic liquid and the organic molecules and hydrogen bonding interactions between anions of the ionic liquid and the organic compounds.

ChemInform Abstract: Triflimide‐Catalyzed Allyl—Allyl Cross‐Coupling: A Metal‐Free Allylic Alkylation.

AbstractA new simple and mild protocol for excellent regioselective direct catalytic allylic alkylation of acetates is presented by using a simple, cheap, and easily accessible catalyst.

Gas-phase S-alkylation of benzenethiol with aliphatic alcohols, ethers, esters, alkyl halides and olefins over halide cluster catalysts of Groups 5 and 6 transition metals

Benzenethiol was reacted with methanol under a hydrogen stream over [(Nb6Cl12)Cl2(H2O)4]·6H2O supported on silica gel. Catalytic activity of the cluster commenced above 250°C, yielding methyl phenyl sulfide. The selectivity was 98% at 400°C. Molybdenum, tantalum and tungsten halide clusters with the same octahedral metal framework also catalyzed the reaction. Primary alcohols with shorter alkyl chains were effective reagents for the S-alkylation. Aliphatic ethers, dialkyl carbonates, orthoesters and alkyl halides were effective reagents for the S-alkylation. When 1-hexene was applied to the reaction, spontaneous and catalytic S-alkylation proceeded simultaneously above 200°C, yielding n-hexyl phenyl sulfide. When alkyl acetates were subjected to this reaction, the niobium cluster afforded S-phenyl thioacetate, and the other clusters afforded alkyl phenyl sulfides selectively. A Brønsted acid site attributable to a hydroxo ligand, which is formed on the cluster complex by thermal activation, is proposed as the active site of the catalysts.

Distribution coefficients of purine alkaloids in water-ammonium sulfate-alkyl acetate-dialkyl phthalate systems

The distribution of purine alkaloids (caffeine, theobromine, theophylline) was studied in the systems: alkyl acetates-dialkyl phtalate-salting-out agent (ammonium sulfate). The quantitative characteristics of the extraction-distribution coefficients (D) and the degree of extraction (R, %) are calculated. The relationships between the distribution coefficients of alkaloids and the length of the hydrocarbon radical in the molecule of alkyl acetate (dialkyl phtalate) are determined. The possibility of predicting the distribution coefficients is demonstrated.

A Facile and Green Protocol for Nucleophilic Substitution Reactions of Sulfonate Esters by Recyclable Ionic Liquids [bmim][X

Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X–) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process ‘greener’.

Interval Sorption of Alkyl Acetates and Benzenes in Poly(methyl acrylate)

We describe a simple, low-cost, gas flow vapor sorption/desorption apparatus that enables “interval” or “differential” experiments on supported polymer films, with control of small step changes in diffusant weight fraction, ω1, to intervals as small as 0.1%. The apparatus permits accurate determination of the binary mutual diffusion coefficient D12(ω1) for ω1 up to at least 3% for “condensable” organic species that typically exhibit very sharp increases in D12 with the diffusant’s weight fraction. We report results for two homologous series of diffusants, n-alkyl acetates and alkyl benzenes, in monodisperse poly(methyl acrylate) (PMA). The Vrentas–Duda free volume theory adequately accounts for the strong concentration dependence of D12 seen in all cases. Nearly constant values of the jump-unit size ratio, ξ, for the homologous set of n-alkyl acetates in the range ξ = 0.61–0.67 closely match those reported previously. For the alkyl benzenes, ξ for benzene (ξ = 0.78 ± 0.04) was higher than those for the larger homologues toluene, ethylbenzene, and cumene (ξ = 0.58–0.60). The ξ values for both homologous series are well-predicted by a free volume based estimate for eccentric diffusants, which jump as a single unit in a mixture whose components contribute different amounts of free volume per jump unit, according to their geometries.

Isolation of caffeine from aqueous media with solvents of homologous structure and its determination by spectrophotometry

The extraction of caffeine by hydrophilic and hydrophobic aliphatic alcohols of linear and branched structure is studied, also by water-soluble alkyl acetates. A correlation between the distribution ratios of caffeine (logD) and the molecular weight of alcohol (logM) is found. The concentration of caffeine in the aqueous phase is determined by UV spectrophotometry. The distribution ratios and recovery of caffeine are calculated.

Final Report of the Cosmetic Ingredient Review Expert Panel on the Safety Assessment of Methyl Acetate

Alkyl acetates, as well as acetic acid and acetate salts, are widely used cosmetic ingredients, with a wide range of functions as fragrances, solvents, or skin-conditioning agents, depending on the specific ingredient. Available data on alkyl acetates, and acetic acid and the alcohol to which they could be metabolized, were considered adequate to support the safety of the entire group in the present practices of use and concentration in cosmetics.

ChemInform Abstract: Synthesis of a Wide Range of Thioesters by Indium Triiodide Catalyzed Direct Coupling Between Alkyl Acetates and Thiosilanes.

AbstractThe method is highly selective for the acetate moiety as is shown by formation of main product (XVII).

Experimental and predicted solubilities of 3,4-dichlorobenzoic acid in select organic solvents and in binary aqueous–ethanol mixtures

Experimental solubilities are reported for 3,4-dichlorobenzoic acid dissolved in methyl butyrate, and in 16 alcohol, 5 alkyl acetate, 5 alkoxyalcohol and 6 ether solvents. Solubilities were also measured in nine binary aqueous–ethanol solvent mixtures at 298.15 K. The measured solubility data were correlated with the Abraham solvation parameter model. Mathematical expressions based on the Abraham model predicted the observed molar solubilities to within 0.12 log units.

Synthesis of a Wide Range of Thioethers by Indium Triiodide Catalyzed Direct Coupling between Alkyl Acetates and Thiosilanes

An indium triiodide-catalyzed substitution of the acetoxy group in alkyl acetates with thiosilanes provides access to a variety of thioethers. The method is efficient for a wide scope of acetates such as primary alkyl, secondary alkyl, tertiary alkyl, allylic, benzylic, and propargylic acetates.

Determination of Abraham model solute descriptors for benzoin based on measured solubility ratios

Experimental solubilities are reported for benzoin dissolved in 1 chloroalkane, 15 alcohols, 5 aromatic hydrocarbons, 5 alkyl acetates, 5 alkoxyalcohols and 3 ethers at 298.15 K. The measured solubility data were mathematically correlated with the Abraham solvation parameter model. The solute descriptors that were calculated for benzoin describe the experimental molar solubility data to within an overall average standard deviation of 0.097 log units.

ChemInform Abstract: Synthesis of Unsymmetrical Alkyl Acetals via Addition of Primary Alcohols to Allyl Ethers Mediated by Ruthenium Complexes.

AbstractThe synthesis of unsymmetrical alkyl acetals via addition of primary alcohols to allyl ethers mediated by various ruthenium complexes is described.

ChemInform Abstract: Thermal Stability and Acidic Strength of Preyssler‐Type Phosphotungstic Acid, H14[P5W30O110Na] and Its Catalytic Activity for Hydrolysis of Alkyl Acetates.

AbstractH14 [P5W30O110Na]·44H2O is obtained from an aqueous solution of K12.5Na1.5 [P5W30O110Na] by cation exchange (Dowex‐50 proton exchange resin), followed by evaporation of the obtained eluent in vacuo at 318 K.