Alkyl Acetates Research Articles

Viscosity of Binary Mixtures of Alkyl Acetates with Hexane, Tetrachloromethane, and Trichloromethane

The viscosity η for binary mixtures of methyl acetate (MA), ethyl acetate (EA), n-amyl acetate (nAA), isoamyl acetate (iAA), decyl acetate (DeA), and dodecyl acetate (DoA) with hexane and of MA, EA, nAA, and iAA with tetrachloromethane and trichloromethane has been measured at 303.15 K over the entire range of composition. The viscosity data have been correlated with the equations of Grunberg and Nissan; Hind, McLaughlin, and Ubbelohde; Tamura and Kurata; Katti and Chaudhri; McAllister; Heric and Brewer; and Auslaender. The viscosity deviations Δη and excess Gibbs energy of activation ΔG*E of viscous flow based on Eyring's theory have been calculated. The results have been analyzed in terms of disruption of dipolar association of alkyl acetate and molecular interaction between alkyl acetate and chloromethane.

GC evaluation of flavour compounds sorption from water solutions by corn starch cryotextures obtained by freezing.

Sorption of essential oil aroma components, n-alcohols and linalool by starch corn cryotexture was studied. Results show that terpene hydrocarbons of Rosmarinus officinalis L. essential oil are sorbed quantitatively from 0.05% water solution by cryotexture due to hydrophobic interactions with starch polysaccharides. Aroma compounds with oxygen atoms within the molecule are sorbed two times less. A templating effect with glucose, sucrose, maltose and some essential oil components was observed. Sorption of n-alcohols C4, C6, C8, linalool and their mixture with alkyl acetates in concentration 0.5-15 mmol/l was carried out. Individual octanol is sorbed by cryotexture on 88%, hexanol on 20%, linalool on 25%. Butanol is not sorbed at the chosen concentration. Synergism in sorption of hexanol from mixture with octanol and alkyl acetates was observed, while a suppression effect of octanol sorption was found for the same mixture.

A novel synthesis of heterocyclic compounds containing coumarin moiety of potential antimicrobial activity.

The chemical behaviours of 4-methyl-2-oxo-2H-benzopyran-7-yl oxoacetyl hydrazine (2) towards some different reagents such as anhydride compounds, aromatic aldehydes, carbon disulphide, and nitrous acid yielded the corresponding pathalazine derivatives (3, 4, 5), hydrazone derivative (6), 1,3,4-oxadiazole derivative (7, 8, 9) and acid azide (10) respectively. Treatment of 10 with absolute alcohols, amines and ethyl amino acid ester gave the corresponding carbamate derivative (11), substituted urea derivative (12) and ethyl substituted alkyl acetate (13) respectively. The biological activity of some synthesized compounds was evaluated.

Sorption of alkyl acetates from aqueous solutions by corn starch cryotextures

Capillary gas chromatography was used to study noncovalent sorption ofn-butyl,n-hexyl, andn-octyl acetates from aqueous solutions by corn starch cryotextures. In the concentration range of 0.5–15.0 mmol L−1, about 38%n-butyl acetate, 70%n-hexyl acetate, and 98%n-octyl acetate are extracted from aqueous solutions. The sorption of the alkyl acetates depends on the alkyl chain length, indicating the hydrophobic character of their interaction with the corn starch cryotexture. No competitive sorption between acetates in the mixture was observed. Binding of alkyl acetates occurs during the cryosponge formation, due probably to the templation at the stage of starch sol, fixation in the cryosponge, and sorption on the surface of its walls.

Excess molar volumes of binary mixtures of alkyl acetates with hexane, tetrachloromethane, and trichloromethane

Excess molar volumes V E have been determined from density ρ measurements, using a vibrating-tube digital densimeter DMA 60/602 for binary mixtures of methyl acetate (MA), ethyl acetate (EA), and n-amyl acetate ( n-AA) with n-hexane (C 6H 12), tetrachloromethane (CCl 4), trichloromethane (CHCl 3) and of iso-amyl acetate ( i-AA) with CCl 4, and CHCl 3. The results we refitted to the polynomial relations to obtain the coefficients and the standard deviations. The results have been analyzed in terms of disruption of dipolar association of alkyl acetates and molecular interactions between alkyl acetate and chloromethane.

Nonthermal Plasma Processing for Controlling Volatile Organic Compounds

Power consumption and byproducts analysis are two key issues that users must address in determining which nonthermal plasma technology is the most appropriate for certain applications. We compared the operating characteristics and power consumption for scaled-up nonthermal plasma devices: pulsed-corona, packed-bed, silent corona, and surface discharge plasma technologies. Advantages and disadvantages of each nonthermal plasma technology are discussed. Understanding of plasma chemistry or byproducts is also essential for the development of nonthermal plasma technologies. Plasma chemical reactions of trichloroethy-lene (TCE) and alkyl acetates were investigated using pulsed-corona and packed-bed reactors. The effects of excited electrons, background gas, moisture, and reactor-dependent phenomena on product distribution and chemical interaction were studied. The initial step of plasma chemical decomposition of TCE can be ascribed to the electron attachment (not to active oxygen species or OH radicals), followed by homolysis and/or heterolysis reactions. Extremely high decomposition of TCE was obtained in nitrogen. Byproduct formation was significantly suppressed under aerated conditions. Alkyl acetate decomposition was affected by reactor type and alkyl chain length

The Reaction of Isatin with Alkoxycarbonylmethylene (Triphenyl)Phosphoranes

Isatin (1) reacted with alkoxycarbonylmethylene(triphenyl)phosphoranes (2) in boiling benzene for about 3 h to give orange yellow crystalline products of alkyl (1,2-dihydro-2-oxo-3H-indol-3-yl)acetates (3). The double bond of compounds 3 was reduced with zinc dust in boiling acetic acid to give 5, which upon methylation with methyl iodide in dry acetone and anhydrous potassium carbonate yielded the corresponding products 6. The structural assignments of the new compounds are based on the spectroscopic results.

Partial Molar Isentropic Compressions of Alkyl Acetates in Water

The ultrasonic speeds in dilute aqueous solutions of eight alkyl acetates (methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl acetates) were measured at (5, 15, 25, 35, and 45) °C by means of a sing-around velocimeter. From these data and density results reported previously, the apparent molar isentropic compressions of the alkyl acetates were evaluated. The results were compared with those for more hydrophilic solutes, alcohols reported earlier, and the effects of chain lengthening and chain branching of the alkyl residues on the compression behavior were discussed.

A novel arylesterase active toward 7-aminocephalosporanic acid from Agrobacterium radiobacter IFO 12607: Purification and characterization

Through the screening of yeasts and bacteria, some strains of Agrobacterium radiobacter have been found to efficiently convert 7-aminocephalosporanic acid (7-ACA) to deacetyl 7-ACA. The enzyme responsible for the conversion was constitutively formed by the bacterium. The 7-ACA deacetylating enzyme was purified from a cell-free extract of A. radiobacter IFO 12607 to homogeneity. The purified enzyme was a tetramer, composed of identical subunits with a molecular mass of 26 kDa, and showed activity toward some derivatives of 7-ACA, aryl acetates, monoacetin and triacetin, but was not active towards alkyl acetates and cephalosporin C. The K m and k cat values of the enzyme for 7-ACA were 8.24 mM and 81 s −1, respectively. Serine inhibitors and sulfhydryl reagents were both found to inhibit the activity. An amino acid sequence, GDSLT, which is the active center motif of an arylesterase, was identified in the amino terminal region. These results indicate that the enzyme belongs to the family of arylesterase (EC 3.1.1.2), and is a new 7-ACA-deacetylating enzyme.

Reduction of alkyl (2-oxocyclohexyl)acetates by baker's yeast.

Baker's yeast reduction of methyl and ethyl (2-oxocyclohexyl) acetates proceeded with enantio- and diastereo-selectivity, affording the corresponding (2S)-trans-alcohols (major), (2S)-cis-alcohols (minor), and the unaltered (1S)-ketones with high optical purity.

Excess Molar Enthalpies and Excess Molar Volumes of Dimethyl Carbonate + Seven Alkyl Acetates at 298.15 K

Excess molar enthalpies and excess molar volumes of dimethyl carbonate + seven alkyl acetates have been determined at 298.15 K and at atmospheric pressure using a flow microcalorimeter and a digital density meter. Values of excess enthalpies and excess volumes increase as the chain length of the acetate molecule is increased. In contrast, the mixtures containing dimethyl carbonate + vinyl acetate show the lowest values. The experimental results have been correlated using the Redlich−Kister equation and have been qualitatively discussed.

Excess molar volumes of binary mixtures containing vinyl acetate + alkyl acetates at 298.15 K. Anomalous behavior of methyl acetate + vinyl acetate mixtures

Excess molar volumes for binary mixtures containing vinyl acetate + methyl acetate, +ethyl acetate, +propyl acetate, +isopropyl acetate, +butyl acetate, +isobutyl acetate, +pentyl acetate, +isopentyl acetate have been determined from density measurements at 298.15 K using an Anton Paar DMA 58 vibrating tube densitometer. A maximum in densities has been observed for the methyl acetate + vinyl acetate system, where samples with different composition showed the same density. Excess molar volumes increase with an increase of the size of the second acetate.

Preparation of ( S)-naproxen by enantioselective hydrolysis of racemic naproxen amide with resting cells of Rhodococcus erythropolis MP50 in organic solvents

Racemic naproxen amide (RS)- 1 was hydrolyzed to enantiomerically pure naproxen (S)- 2 in water-saturated organic solvents with log P values between 2.0 and 0.17 using immobilized resting cells of the bacterial strain Rhodococcus erythropolis MP50. Alkyl acetates are the most suitable solvents concerning solubility of (RS)- 1 and enzyme activity. In butyl acetate with 3 vol% DMSO as cosolvent and an increased water content of the immobilized cells the rate of hydrolysis was an optimum. Under these reaction conditions a preparative scale application gave after 45 h, at a conversion rate of 48%, (S)- 2 with >99% ee and an isolated yield of 84%.

Conductometric Study of Short Chain Alkanones and Alkyl Acetates within Anionic Micelles

The interaction of short chain alkanones and alkyl acetates (alkyl group = methyl to propyl) with the micelles of an anionic surfactant, sodium dodecyl sulfate (SDS), was studied by the conductivity method at 25.0°C. The critical micelle concentration (CMC) of SDS decreases linearly with the increase in the concentration of additives in the low concentration regions. The water-micelle partition coefficient, K x , and the standard free energy change of penetration, ΔG 0 P , of each additive from water to micelle were calculated from the limiting slope (dCMC/dC a ). The free energy change per methylene group, AΔG 0 (CH 2 ), has also been evaluated. The K x values for a given additive increases with the increase in alkyl chain.

Heat Capacities of Some Alkyl Acetates at 295-323 K

Molar heat capacities Cp,m at constant atmospheric pressure have been determined with a typical uncertainty of about 0.3% for eight liquid alkyl acetates H(CH2)nOCOCH3 (n = 6-12, 14), over the temperature range 295-323 K. The Cp,m values were found to be a linear function of temperature. A comparison of experimental data with those predicted by the group additivity method demonstrated a rather limited capability of the additivity scheme to predict correctly the Cp,m values for higher (n > 10) homologues in the series.

Dinuclear iron(III)–metal(II) complexes as structural core models for purple acid phosphatases †

A series of mixed-valent iron and mixed-metal FeIII–MII (M = Zn, Cu, Ni or Co) complexes of the phenolate-hinged dinucleating ligand 2,6-bis{[bis(2-pyridylmethyl)amino]methyl}-4-tert-butylphenolato(1–), bpbp– have been prepared and characterized. Both exogenous bidentate bridging groups and different terminal ligands bound to each different metal ion at the exogenous site were identified. The structure of the mixed-valence complex [(bpbp)Fe2(F)2(H2O)2][BF4]2 confirms that it is a rare example of a dimetallic complex of a single-atom hinged acyclic dinucleating ligand with a ‘non-bridged’ arrangement at the exogenous bridging site. Mössbauer spectroscopy indicates valence trapping in this complex with the parameters, ΔEQ 3.242 mm s–1, δ 1.169 mm s–1 and ΔEQ 0.221 mm s–1, δ 0.460 mm s–1, respectively for the high spin Fe2+ and high spin Fe3+ ions. Crystals of [(bpbp)Fe2(F)2(H2O)2][BF4]2·4H2O are triclinic, space group P (no. 2), with a = 12.695(1), b = 19.197(2), c = 10.202(1) Å, α = 102.95(1), β = 97.61(1), γ = 93.76(1)°, Z = 2. The structure was refined to R = 0.1009 on F using 4338 reflections with I > 2σ(I) (wR2 on all data and F 2 = 0.3522). The FeII and FeIII atoms are bridged asymmetrically by the phenolic oxygen atom of bpbp– with FeII–O 2.175(6) Å and FeIII–O 2.033(6) Å with a FeIII · · · FeII distance of 3.726(2) Å. The two terminal fluoride ions are bound to the FeIII atom and strongly hydrogen bonded to two water molecules bound to the adjacent FeII atom. This complex may model the mode in which fluoride ions bind to the active site of the purple acid phosphatases (PAPs) thereby inhibiting the activity of these enzymes. Tetrahedral oxo anions are known also to inhibit PAPs and to mimic this inhibition a FeIII–ZnII complex incorporating molybdate bridging groups was prepared. Crystals of [(bpbp)FeZn(MoO4)2]·C3H7OH· 2H2O are monoclinic, space group P21/n with a = 11.773(13), b = 21.394(7), c = 17.001(11) Å and β = 90.98(7)°, Z = 4. The structure was refined to R = 0.0434 on F using 3758 reflections with I > 2σ(I) (wR2 on all data and F 2 = 0.1339). The FeIII · · · ZnII distance is 3.819(4) Å. A series of acetate-bridged complexes were prepared by the novel method of diffusing ethyl acetate or isopropyl acetate into mixtures of Hbpbp and iron perchlorate in the presence and absence of a second type of metal ion. The acetate bridging groups are the result of the hydrolysis of the alkyl acetate. These complexes have the general formulation [(bpbp)FeM(CH3CO2)2][ClO4]2. Crystals of [(bpbp)FeCu(CH3CO2)2][ClO4]2·0.5CH3OH are monoclinic, space group P21/n

ChemInform Abstract: Crystal Structure and Stereoselective Solid‐State Photodimerization of 1‐(9‐Anthryl)alkyl Acetates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Crystal and molecular structure of 1,3-(dis/tal) derivatives of p-tert-butyl calix[4]arene. Evidence for conformational control and self-inclusion involving weak C-H … π interactions

Abstract X-Ray crystallographic analyses of four p-tert-butylcalix[4]arenes in which two 1,3-(distal)phenolic groups on the lower rim have been derivatised with cyanomethyl, amino ester and alkyl acetate residues, are reported. Intramolecular hydrogen bonding between the free phenolic groups and their proximal ethereal oxygen atoms is evident in all four compounds. With the exception of the ethyl ester, these calixarenes adopt very distorted cone conformations in the solid state. The ethyl ester adopts a much less distorted cone conformation with the distinguishing feature of self-inclusion of an ethoxy residue of one ester group on the lower rim within the hydrophobic cavity of a neighbouring molecule within the crystal. Factors which control the conformations of these molecules are discussed.

ChemInform Abstract: Unexpected Alkylation Reaction of Amines, Acids and Phenols by Alkyl( triphenylphosphoranylidene)acetates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Crystal Structure and Stereoselective Solid-State Photodimerization of 1-(9-Anthryl)alkyl Acetates

Abstract X-Ray structure analyses of 1-(9-anthryl)alkyl acetates [AnCH(OAc)R; An = 9-anthryl, R = Me (1a), Et (1b), i-Pr (1c), t-Bu (1d), CF3 (1e)] indicated that these molecules adopted similar conformations in which the bond connecting the chiral carbon and the substituent was oriented almost perpendicular to the anthracene plane. In the crystals of 1b—1e two adjacent anthracenes related by an inversion center was stacked with a short interplane distance (3.5—3.6 Å), which was favorable for the formation of the meso head-to-tail dimer. Photolysis of crystals of 1b, 1c, and 1e afforded meso-dimers in almost 100% yield, while 1d was photostable. The quantum yield of dimerization for 1b (0.16) was higher than that in solution. Although the dimerization did not proceed in single crystal-to-single crystal fashion, the observed high selectivity suggested that the reaction took place between the π-stacking pair even when the crystalline lattice of the monomer was destroyed. Irradiation of 1a—1e in benzene solution gave meso- and dl-head-to-tail dimers in a ratio of 1 : 1. The quantum yield of dimerization decreased with increase in the size of the substituent.