Ethyl Acetate Molecules Research Articles

Molecular interactions in ethyl acetate-chlorobenzene binary solution: Dielectric, spectroscopic studies and quantum chemical calculations

Dielectric studies using Time Domain Reflectometry method has been carried out on the binary solution of Ethyl acetate (EA) with Chlorobenzene (CBZ) over the entire composition range. Spectroscopic (FTIR and 13C NMR) signatures of neat EA, CBZ and their equimolar binary solution have also been recorded. The results of the spectroscopic studies favour the presence of (CBZ) CH⋯OC (EA), (EA) methylene CH⋯π electrons (CBZ) and (EA) methyl CH⋯Cl (CBZ) contacts which have been validated using quantum chemical calculations. Dimerization of CBZ has been identified. Presence of β-clusters has been identified in all the solutions. Although EA and CBZ molecules have nearly equal molar volumes, CBZ molecules experience larger hindrance for the rotation than EA molecules. Very small excess dielectric constant (εE) values may be correlated with weak heteromolecular forces and/or closed heteromolecular association.

Denaturation of DNA in Ternary Mixed Solution of Water/Hydrophilic/Hydrophobic Organic Solvent

Denaturation was examined for the first time in a ternary mixed solution of water/hydrophilic/ hydrophobic organic solvent using λ-DNA and a plasmid as models. The absorbance of λ-DNA and the plasmid at 260 nm gradually increased for several days up to 1.68 and 1.38 times the initial values, respectively, in a water/acetonitrile/ethyl acetate (15:3:2, volume ratio) mixed solution, whereas there was little change in a water/acetonitrile (15:3, volume ratio) mixed solution. The plasmid treated with the ternary mixed solution was also examined with agarose gel electrophoresis. These experimental data indicated that λ-DNA changed from a double helix structure to a single helix structure and that the plasmid partially transformed to generate a denaturation bubble in the structure. The new idea of using the ternary mixed solution first enabled the interaction of the hydrophobic organic solvent (e.g., ethyl acetate) molecule with the double helical structure of DNA, leading to specific slow-proceeding denaturation.

Adsorption of Ethyl Acetate from Water by Nanoporous Carbon Prepared from Waste Materials

The adsorption of ethyl acetate, a volatile organic compound, on activated carbons, synthesized from various precursors based on by-products and waste materials—polymer, biomass, coal tar pitch—was studied. The activated carbons were prepared by thermochemical treatment of the precursors, carbonization, and subsequent activation with water vapor. Surface and textural properties of obtained carbon adsorbents were characterized by low-temperature N2 adsorption, Boehm’s method, etc. The activated carbons are distinguished by relatively high surface area and developed pore structure. The adsorption investigations were performed with water solutions of ethyl acetate, and the obtained results fit well the Langmuir model, as well as the Freundlich model. All activated carbons demonstrated considerably high adsorption capacity in the range 160–450 mg/g. The obtained data indicate that the adsorption ability of activated carbon toward ethyl acetate depends on the surface area, and it increases with increasing the content of mesopores, where ethyl acetate molecules are preferably adsorbed.

The crystal structure of Z-Gly-Aib-Gly-Aib-OtBu

The synthetic peptide Z-Gly-Aib-Gly-Aib-OtBu was dissolved in methanol and crystallized in a mixture of ethyl acetate and petroleum ether. The crystals belong to the centrosymmetric space group P4/n that is observed less than 0.3% in the Cambridge Structural Database. The first Gly residue assumes a semi-extended conformation (φ ±62°, ψ ∓131°). The right-handed peptide folds in two consecutive β-turns of type II' and type I or an incipient 310 -helix, and the left-handed counterpart folds accordingly in the opposite configuration. In the crystal lattice, one molecule is linked to four neighbors in the ab-plane via hydrogen bonds. These bonds form a continuous network of left- and right-handed molecules. The successive ab-planes stack via apolar contacts in the c-direction. An ethyl acetate molecule is situated on and close to the fourfold axis.

An idealized molecular geometry library for refinement of poorly behaved molecular fragments with constraints

An idealized molecular geometry library with 40 geometries of molecules and ions optimized by density functional theory methods has been created. All geometries are accessible through a web site. The library entries are tailored for constrained (also known as rigid body) refinements of problematic small-molecule structures with theOLEX2andSHELXLsoftware packages. The library application is demonstrated with the refinement of a Pd complex,trans-Pd(dimethyl sulfoxide)(OH2)(trifluoroacetate)2, that co-crystallizes in a 2:1 ratio with a solvent molecule of ethyl acetate disordered over an inversion center. Alternative approaches to constrained refinements are discussed.

Pallidol hexaacetate ethyl acetate monosolvate

The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ▶). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100 Å) is 54.73 (6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70 (5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = −70.24 (14), −114.43 (10) and −72.54 (13)°]. In the crystal, a three-dimensional architecture is sustained by C—H⋯O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside.

Influence of CeO2 morphology on the catalytic oxidation of ethanol in air

Nano-CeO2 catalysts of different shapes were synthesized at different hydrothermal crystallization temperatures from an alkaline aqueous solution. X-ray diffraction (XRD), transmission electron microscope (TEM), and H2 temperature-programmed reduction (H2-TPR) were used to study the synthesized nano-CeO2 catalyst samples. The catalytic properties of the prepared nano-CeO2 catalysts for the catalytic oxidation of ethanol in air were also investigated. TEM analysis showed that CeO2 nanorod and nanocube catalysts have been synthesized at hydrothermal crystallization temperatures of 373K and 453K, respectively. XRD results showed that the synthesized nano-CeO2 catalysts have similar cubic fluorite structures. H2-TPR results indicated that CeO2 nanorod and nanocube catalysts exhibit different reduction behaviors for H2 and that the nanorod catalyst has better low-temperature reduction performance than the nanocube catalyst. Ethanol catalytic oxidation results indicated that oxidation and condensation products (including acetaldehyde, acetic acid, CO2, and ethyl acetate) have been produced from the prepared catalysts. The ethyl acetate and acetic acid can be ignited by ethanol at low temperature on the CeO2(R) catalyst to give low catalytic combustion temperature for ethyl acetate and acetic acid molecules. CeO2 nanorods gave ethanol oxidation conversion rates above 99.2% at 443K and CO2 selectivity exceeding 99.6% at 483K, while CeO2 nanocubes gave ethanol oxidation conversion rates of about 95.1% until 508K and CO2 selectivity of only 93.86% at 543K. CeO2 nanorod is a potential low-cost and effective catalyst for removing trace amounts of ethanol to purify air.

Tetraamido‐oxacalix[4]arene Derivatives: Synthesis, Structures and Supramolecular Assemblies

AbstractTetraamido‐oxacalix[4]arene derivatives have been synthesized via the reactions of tetraamino‐oxacalix[4]arene with excess butyryl chloride, octanoyl chloride, benzoyl chloride and p‐toluenesulfonyl chloride, respectively. 1H NMR results suggest that these oxacalix[4]arene derivatives preferentially adopt the 1,3‐alternate (saddle‐like) conformation in solution, which were also the case in the solid state as demonstrated by single crystal X‐ray analysis. A dimerized slipped capsule could be formed by tetra‐butyramido‐oxacalix[4]arene in the solid state via intermolecular hydrogen bond interactions under the assistance of two encapsulated methanol molecules. On the other hand, a molecular cavity was formed by tetra‐p‐toluenesulfonamido‐oxacalix[4]arene which can encapsulate a solvent molecule of ethyl acetate.

{5′-O-[Bis(4-methoxyphenyl)(phenyl)methyl]-2′-deoxy-β-D-threopentofuranosyl}thymine ethyl acetate 0.25-solvate

The title compound, C(31)H(32)N(2)O(7)·0.25C(4)H(8)O(2), is a key intermediate in the synthesis of [(18)F]fluorine-labelled thymidine ((18)F-FLT), which is the most widely used molecular imaging probe for positron emission tomography (PET). The crystallographic asymmetric unit contains two independent thymine molecules plus one partially occupied site for an ethyl acetate molecule. The two independent thymine molecules show similar geometrical features, except that the dimethoxytrityl groups adopt different orientations with respect to the remainder of the molecule. Each thymine base adopts an anti conformation with respect to the attached deoxyribose ring, and the deoxyribose rings show C3-endo puckering. The conformation of the side chain at the C1 position of the deoxyribose ring is gauche+. Intermolecular N-H···O and O-H···O hydrogen bonds link the molecules into one-dimensional chains.

Separation of ethyl acetate (EA)/water by tubular silylated MCM-48 membranes grafted with different alkyl chains

The MCM-48 type materials and membranes had been successfully silylated with different alkyl chains (methyl, propyl and n-octyl). The silylated MCM-48 membranes prepared on supports with pore size of 1 μm had a good effect on separation of the ethyl acetate (EA)/water mixture. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), IR spectroscopy, pervaporation. These results showed that the silylated MCM-48 type materials could adsorb large amount of EA, about 145 mg/g for C 8H 17-MCM-48 at 7 kPa at the room temperature, which was ten times of the Si-MCM-48′. Besides this, the C 8H 17-MCM-48 membranes had EA/H 2O separation factor of 251 at room temperature and 123 at 50 °C with the total flux 4.3 and 6.6 kg/(m 2 h), respectively. The long-chain alkyl groups grafted in the membrane pore could enhance temperature tolerance of the membrane for separating EA/H 2O. Under the same conditions, the CH 3- and C 3H 7-MCM-48 membranes had lower separation factor and larger total flux. The phenomenon in the separation experiments was controlled by the solution-diffusion mechanism. EA molecules were firstly adsorbed in the silylated pores selectively and made up a compact hydrophobic membrane, which could prevent the penetration of the water, resulting in the high EA selectivity.

(2RS,3SR,10SR,11RS)-3,10-Diphenoxy-18,21-dioxa-5,8-diazapentacyclo[20.4.0.02,5.08,11.012,17]hexacosa-1(26),12,14,16,22,24-hexaene-4,9-dione ethyl acetate hemisolvate

In the title compound, C34H30N2O6·0.5C4H8O2, there are two mol­ecules in the asymmetric unit and the structure is stabilized by C—H⋯O inter­actions. The two nonsolvent mol­ecules of the asymmetric unit are linked together by a weak C—H⋯O hydrogen bond. The ethyl acetate mol­ecule is present as a space filler and does not participate in the hydrogen-bonding network.

Adsorption and Diffusion of Ethyl Acetate on the Chromium-Based Metal–Organic Framework MIL-101

The adsorption equilibrium and diffusion of ethyl acetate (EA) on chromium-terphthalate-based crystals (MIL-101) are experimentally studied. The MIL-101 synthesized in this work shows an extra-high surface area of 5014 m2·g–1 (Langmuir). Adsorption isotherms and kinetic curves of EA on the MIL-101 are measured by a gravimetric method. Results show that the isotherms of EA can be fitted favorably by the Langmuir equation. The adsorption capacity of the MIL-101 for EA is up to 10.5 mmol·g–1 at 288 K and 54 mbar. Diffusion coefficients of EA within the MIL-101 are in the range of (1.617 to 2.264)·10–10 cm2·s–1 in (288 to 318) K with a lower activation energy of 8.361 kJ·mol–1. The isosteric heat of EA adsorption on the MIL-101 is within the range of (36.48 to 42.25) kJ·mol–1. The isosteric adsorption heat increased slightly with the amount adsorbed of EA, implying the existence of favorable lateral interactions between EA molecules. Multiple adsorption–desorption cycles are conducted at 298 K to examine the reversibility of EA adsorption on the MIL-101. Adsorptions were performed separately at (2, 3, 5, 7, and 10) mbar, and desorptions are performed at 0.05 mbar. Experimental results show that the EA adsorption on the MIL-101 is highly reversible and the desorption efficiency of EA is up to 98.4 %.

Synthesis and Solid-State Rotational Dynamics of Molecular Gyroscopes with a Robust and Low Density Structure Built with a Phenylene Rotator and a Tri(meta-terphenyl)methyl Stator

Recent studies suggest that the rotational dynamics in crystals of molecular gyroscopes become more favorable (i.e., faster) when the packing coefficient of the corresponding lattice is decreased by increasing the steric bulk of the stator, as expected for structures with high protuberances or deep cavities. In an effort to explore the effects of increased stator size on the solid-state dynamics of these crystalline models for molecular machines, molecular gyroscope 4 with an “exploded” bis(tri(meta-terphenyl)methyl) stator was synthesized. Single crystal X-ray diffraction analysis revealed a packing structure with two crystallographically distinct gyroscope molecules and four ethyl acetate molecules per unit cell. Although a relatively low packing coefficient of 0.68 was determined for the corresponding packing motif, we noticed that rotators at the two sites have significantly different environments. The solid state rotational dynamics of the two central phenylenes in an ethyl acetate clathrate of 4 were explored by variable-temperature 13C NMR with cross-polarization with magic angle spinning (13C CPMAS NMR) and by quadrupolar echo 2H NMR measurements with isotopically labeled samples. It was found that the increased stator size does indeed allow for more free-volume and faster rotational dynamics as compared to molecular gyroscopes with smaller or more globular stators. However, the two crystallographic sites experience different rotational dynamics, suggesting that the average density available from the packing coefficient is a very crude indicator of solid-state dynamics.

Bis[3α,7α,12α-tris(4-nitrobenzoyloxy)-5β-cholan-24-yl] disulfide–ethyl acetate–n-hexane (4/4/1)

The crystal structure of the title compound, C90H100N6O24S2·C4H8O2·0.25C6H14, solved and refined against synchrotron diffraction data, contains two formula units in the asymmetric unit with the all-trans n-hexane mol­ecule having half-occupancy and one of the ethyl acetate mol­ecules disordered over two positions. The two symmetry-independent disulfide mol­ecules are assembled by approximate face-to-face and face-to-edge inter­actions between their 4-nitro­benzo­yloxy groups into an inter­twined dimer having a double-helix-type structure. The centrally placed disulfide bridges in the two symmetry-independent mol­ecules exhibit different helicity as shown by the C—S—S—C torsion angles of 71.0 (1) and −92.5 (1)°.

Ethyl Acetate Adsorption onto Activated Carbon

The adsorption and desorption of ethyl acetate on a coconut-based activated carbon has been studied using static and flow adsorption methods at different temperatures from 295 K to 325 K. The adsorbed state of ethyl acetate was studied using nitrogen adsorption at 77 K after the pre-adsorption of ethyl acetate. The adsorption isotherms of ethyl acetate were of Type I in the IUPAC classification, suggesting micropore filling by ethyl acetate molecules. The micropore volume of the activated carbon as evaluated from ethyl acetate adsorption using the liquid density of ethyl acetate agreed well with that from nitrogen adsorption. Nitrogen adsorption after pre-adsorption of ethyl acetate indicated considerably packed molecular states of ethyl acetate molecules within the micropores. Thus, ethyl acetate molecules can migrate to the deeper parts of micropores in the case of static adsorption measurements. However, the specific surface area evaluated from ethyl acetate adsorption was nearly 40% smaller than that ...

Polymorphism or pseudopolymorphism of a macrocyclic compound: helical structure, layered structure and pseudorotaxane constructed by weak intermolecular interactions

Molecules of macrocyclic aromatic hydrocarbon 1 assembled to form various three-dimensional (3D) structures via weak intermolecular interactions, including aromatic–aromatic interactions (1a–d). In the crystal obtained from a chloroform and acetonitrile mixture (1a), the molecules arranged in a columnar stack with a progressive helical twist between adjacent molecules due to intermolecular aromatic–aromatic interactions. The chirality of the helices was spontaneously resolved within individual single crystals. In the crystal obtained from a chloroform and nonane mixture (1b), the molecules formed a columnar stack through tilted T-shaped aromatic–aromatic interactions. Furthermore, in the crystal obtained by vapour diffusion of n-hexane or ethyl acetate into a chloroform solution, inclusion compounds (1c and 1d) were formed via van der Waals interactions between the guest molecule and the benzene ring of the biphenyl unit. The n-hexane penetrated 1 to construct [3]pseudorotaxane and an ethyl acetate molecule was trapped by 1.

Inclusion compounds based on 16(S)-dihydro- and 15-ene-steviols

XRD is used to study the structures of inclusion compounds of diterpenoid 15-ene-steviol with chloroform and 16-S-dihydrosteviol with chloroform and ethyl acetate. In all three cases, the guest-host ratio is 1:2; by means of a branched system of hydrogen bonds, diterpenoid molecules form a three-dimensional associate with helical voids, in which solvent molecules are located. Crystals of all three complexes are isostructural, the ethyl acetate molecule being localized in the corresponding inclusion compound, while solvent molecules are disordered in complexes with chloroform.

The Study on Pervaporation Behaviors of Dilute Organic Solution Through PDMS/PTFE Composite Membrane

As an energy-efficient alternative to distillation, pervaporation has been widely combined with fermentation to remove organic compounds from their dilute solutions in a fermentation broth. In this work, the organic permselective composite membrane is prepared by coating polydimethylsiloxane (PDMS) cross-linked with n-heptane on the substrate of polytetrafluoroethylene(PTFE) membrane. The separation behavior is studied in different dilute organic solutions, which include acetone dilute solution, butanone dilute solution, cyclohexanone dilute solution, ethanol dilute solution, isopropanol dilute solution, n-butyl alcohol dilute solution, acetic acid dilute solution, and ethyl acetate dilute solution. Most of these solutions are main reaction products or by-products from fermentation process. The effects of solubility of organics in the membrane, molecular weight, and polarity of the organics on the pervaporation performance are investigated. The effects of operating temperature and organic concentration in the feed solutions on the performance of composite membrane are studied as well. The experimental results show that molecular volume has less influence than solubility and molecular polarity for these organic solvent. The selectivity of PDMS membrane to ethyl acetate is relative high due to good solubility and diffusion of ethyl acetate molecules in polymer.

In situ hydrothermally synthesized mesoporous LaCoO3/SBA-15 catalysts: High activity for the complete oxidation of toluene and ethyl acetate

Abstract Mesoporous y LaCoO 3 /SBA-15 ( y = 10–50 wt%) catalysts were prepared and characterized for the combustion of toluene and ethyl acetate (EA). The results show that well-ordered mesoporous LaCoO 3 /SBA-15 catalysts of high surface areas (338–567 m 2 /g) could be fabricated by a facile in situ method of hydrothermal treatment. The particles of perovskite-type LaCoO 3 were highly dispersed on the walls of pore channels. The ordered mesoporous structure and high dispersion of LaCoO 3 are beneficial to the adsorption and activation of toluene and EA molecules. We found that in terms of specific activity, the in situ fabricated 35LaCoO 3 /SBA-15 and 40LaCoO 3 /SBA-15 is, respectively, superior to 35LaCoO 3 /SBA-15_ imp (generated by incipient wetness impregnation method) and bulk LaCoO 3 (prepared by sol–gel method) in catalytic performance. Based on the above results, we conclude that the excellent performance can be attributed to the good dispersion of highly reducible LaCoO 3 species in y LaCoO 3 /SBA-15.

2,2′-Bis(9-hydroxy-9-fluorenyl)biphenyl–ethyl acetate (1/1)

In the title host–guest compound, C38H26O2·C4H8O2, the ethyl acetate mol­ecule (guest), which adopts a fully extended conformation, and the biphenyl derivative (host) are connected via O—H⋯O hydrogen bonds [H⋯O = 1.90 (3) Å] into discrete assemblies. The hydro­carbon skeleton of the host mol­ecule deviates only slightly from C2 symmetry. The OH groups of the host are involved in intra­molecular O—H⋯O hydrogen bonding [H⋯O = 1.83 (3) Å].