H-FER-Catalyzed Conversion of Methanol to Ethanol and Dimethyl Ether: a First-Principles DFT Study

ABSTRACT Methanol adsorption and dehydration reactions within zeolites represent important steps in the catalytic conversion process to form long-chain hydrocarbons. Herein, first-principles density functional theory (DFT) is employed in the determination of methanol adsorption and conversion in ferrierite (FER), where we predict the fundamental adsorption geometries and energetics of methanol adsorption. The methanol molecule is shown to physisorb at all explored binding sites, stabilized through hydrogen-bonded interactions with the acid site atOmeth-Hframbond distances ranging from 1.33-1.51 A. We demonstrate that the zeolites' adsorption capability is affected by the silicon/aluminium ratio, with stronger adsorptions predicted in the material with silicon to aluminium fractions of 5 than 8. The adsorption strength is also found to vary depending on the tetrahedral binding site, with the T1O2 site yielding the most stable methanol adsorption structure in the Si/Al ratio = 5(Eads = -22.5 kcal mol-1), whereas the T1O1 site yields the most stable adsorption geometry (Eads = -19.2 kcal mol-1) in the Si/Al ratio = 8. Upon translational and rotational motion, methanol is protonated resulting in the breaking of its C-O bond to form a methoxy species bound to the framework oxygen (O-CH3 distance of 1.37 A), whereas the water molecule is stabilized at the acid site through H-bonding (Owat-H = 2.0 A). Further reaction between the methoxy species and a second methanol molecule results in the formation of ethanol and protonated dimethyl ether, with adsorption energies of -42 and -25 kcal mol-1, respectively. The results in this study provide atomistic insight into the effect of acidity of the FER zeolite on the adsorption and conversion of methanol. Keywords: Zeolites, ferrierite, methanol adsorption, acid sites, density functional theory (DFT).

μ2-Methanol-κ2 O:O-bis[(1,10-phenanthroline-κ2 N,N′)bis(2,3,4,5-tetrafluorobenzoato)-κO;κ2 O,O′-copper(II)]

In the title compound, [Cu2(C7HF4O2)4(C12H8N2)2(CH3OH)], the molecule lies on a twofold rotation axis in space group C2/c. The Cu2+ ion exhibits a distorted octahedral sphere with two N atoms from the phenanthroline ligand, three O atoms from the 2,3,4,5-tetrafluorobenzoate ligands and one O atom from a methanol molecule. The distortion from an octahedral shape is a consequence of the Jahn–Teller effect of CuII and the small bite angle for the bidentate fluorobenzoate ligand [54.50 (11)°]. The methanol molecule bridges two symmetry-related CuII atoms to form the complete molecule. In the bidentate fluorobenzoate ligand, one F atom is disordered over two positions of equal occupancy. In the crystal structure, only weak intermolecular interactions are observed.

Crystal structures of binuclear complexes of gadolinium(III) and dysprosium(III) with oxalate bridges and chelating N,N′-bis(2-oxidobenzyl)-N,N′-bis(pyridin-2-ylmethyl)ethylenediamine (bbpen2−)

The reaction between mononuclear [Ln(bbpen)Cl] [Ln = Gd or Dy; H2bbpen = N,N′-bis(2-hydroxybenzyl)-N,N′-bis(pyridin-2-ylmethyl)ethylenediamine, C28H30N4O2] and potassium oxalate monohydrate in water/methanol produced the solvated centrosymmetric isostructural binuclear (μ-oxalato)bis{[N,N′-bis(2-oxidobenzyl-κO)-N,N′-bis(pyridin-2-ylmethyl-κN)ethylenediamine-κ2 N,N′]dilanthanide(III)}–methanol–water (1/4/4) complexes, [Ln 2(C28H28N4O2)2(C2O4)]·4CH3OH·4H2O, with lanthanide(III) = gadolinium(III) (Ln = Gd) and dysprosium(III) (Ln = Dy), in high yields (ca 70%) directly from the reaction mixtures. In both complexes, the lanthanide ion is eight-coordinate and adopts a distorted square-antiprismatic coordination environment. The triclinic (P\overline{1}) unit cell contains one dimeric unit together with four water and four methanol molecules; in the final structural model, two of each type of solvating molecule refine well. In each lanthanide(III) dimeric molecule, the medium-strength O...H—O hydrogen-bonding pattern involves four oxygen atoms, two of them from the phenolate groups that are `bridged' by one water and one methanol molecule. These interactions seem to contribute to the stabilization of the relatively compact shape of the dimer. Electron densities associated with an additional water and methanol molecule were removed with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. These two new compounds are of interest with respect to magnetic properties.

NEW MX2 AND M’Cl3 (M = Cu, Zn; M’= Y, Dy, Pr; X = Cl, Br) MALEATO COMPLEXES AND TETRAPHENYLANTIMONY FORMIATE ADDUCT: SYNTHESIS AND INFRARED STUDY

<p>Eleven complexes and adduct have been synthesized and studied by infrared. The suggested structures are discrete with tetrahedral, trigonal bipyramidal, square planar or octahedral environments around Zn, Ni, Hg and Cu centres – the coordination number is eight in the yttrium compound and ten in the dysprosium one-. The maleate anion behaves as a bidentate, a monochelating, a bichelating or a tetradentate ligand while the formiate anion behaves as a monodentate ligand. For compounds containing a protonated amine or a methanol molecule, when hydrogen bonds are considered a supramolecular architecture may be obtained.</p>

Crystal structure of (methanol-κO)[5,10,15,20-tetrakis(2-aminophenyl)porphyrinato-κ4 N]zinc(II)–chloroform–methanol (1/1/1)

In the crystal structure of the title compound, [Zn(C44H32N8)(CH3OH)]·CHCl3·CH3OH, the ZnII cation is coordinated by four porphyrin N and one methanol O atom within a slightly distorted square-pyramidal environment and is shifted out of the porphyrin plane towards the direction of the methanol molecule. The methyl group of the coordinating methanol molecule is disordered over two sets of sites. The porphyrin backbone is nearly planar and the phenyl rings are almost perpendicular to the porphyrin plane. As is typical for picket-fence porphyrins, all four ortho substituents of the meso-phenyl groups (here the amino groups) are facing to the same side of the porphyrin molecule. In the crystal structure, two neighbouring porphyrin complexes form centrosymmetric dimers that are connected via O—H...N hydrogen bonding. With the aid of additional N—H...N and C—H...N hydrogen bonding, these dimers are stacked into columns parallel to [010] that are finally arranged into layers parallel to (001). Between these layers channels are formed where chloroform solvent molecules are located that are connected to the porphyrin complexes by weak C—H...Cl hydrogen bonding. There are additional cavities in the structure where some small residual electron density is found, indicating the presence of disordered methanol molecules, but a reasonable model could not be refined. Therefore the contribution of the electron density associated with the methanol solvent molecule was removed with the SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9–18] in PLATON. Nevertheless, the given chemical formula and other crystal data take into account the methanol solvent molecule.

Crystal structure of a supramolecular lithium complex of p-tert-butylcalix[4]arene

Crystals of a supramolecular lithium complex with a calix[4]arene derivative, namely tetramethanollithium 5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxy-28-oxidocalix[4]arene methanol monosolvate, [Li(CH3OH)4](C44H55O4)·CH3OH or [Li(CH3OH)4]+·(calix[4]arene−)]·CH3OH (where calix[4]arene− represents a mono-anion species because of deprotonation of one H atom of the calixarene hydroxy groups), were obtained from p-tert-butylcalix[4]arene reacted with LiH in tetrahydrofuran, followed by recrystallization from methanol. The asymmetric unit comprises one mono-anionic calixarene molecule, one Li+ cation coordinated to four methanol molecules, and one methanol molecule included in the calixarene cavity. The calixarene molecule maintains a cone conformation by intramolecular hydrogen bonding between one phenoxide (–O−) and three pendent calixarene hydroxy groups (–OH). The coordinated methanol molecules around the metal cation play a significant role in forming the supramolecular assembly. The crystal structure of this assembly is stabilized by three sets of intermolecular interactions: (i) hydrogen bonds involving the –OH and –O− moieties of the calixarene molecules, the –OH groups of the coordinated methanol molecules, and the –OH group of the methanol molecule included in the calixarene cavity; (ii) C—H...π interactions between the calixarene molecules and/or the coordinated methanol molecules; (iii) O—H...π interactions between the calixarene molecule and the included methanol molecule.

Adsorption of methanol molecule on graphene: Experimental results and first-principles calculations

Adsorption properties of methanol molecule on graphene surface are studied both theoretically and experimentally. The adsorption geometrical structures, adsorption energies, band structures, density of states and the effective masses are obtained by means of first-principles calculations. It is found that the electronic characteristics and conductivity of graphene are sensitive to the methanol molecule adsorption. After adsorption of methanol molecule, bandgap appears. With the increasing of the adsorption distance, the bandgap, adsorption energy and effective mass of the adsorption system decreased, hence the resistivity of the system decreases gradually, these results are consistent with the experimental results. All these calculations and experiments indicate that the graphene-based sensors have a wide range of applications in detecting particular molecules.

NEW MX2 AND M’Cl3 (M = Cu, Zn; M’= Y, Dy, Pr; X = Cl, Br) MALEATO COMPLEXES AND TETRAPHENYLANTIMONY FORMIATE ADDUCT: SYNTHESIS AND INFRARED STUDY

Eleven complexes and adduct have been synthesized and studied by infrared. The suggested structures are discrete with tetrahedral, trigonal bipyramidal, square planar or octahedral environments around Zn, Ni, Hg and Cu centres – the coordination number is eight in the yttrium compound and ten in the dysprosium one-. The maleate anion behaves as a bidentate, a monochelating, a bichelating or a tetradentate ligand while the formiate anion behaves as a monodentate ligand. For compounds containing a protonated amine or a methanol molecule, when hydrogen bonds are considered a supramolecular architecture may be obtained.

Crystal structure of bis(pyridine-4-carbothioamide-κN1)bis(thiocyanato-κN)cobalt(II) methanol monosolvate

The asymmetric unit of the title compound, [Co(NCS)2(C6H6NS)4]·CH3OH, consists of one cobalt(II) cation, two thiocyanate anions, four pyridine-4-carbothioamide ligands and one methanol molecule that are located in general positions. The CoIIcations are coordinated by two terminal N-bonding thiocyanate anions and four N-bonding pyridine-4-carbothioamide ligands, resulting in discrete and slightly distorted octahedral complexes. These complexes are linked into a three-dimensional networkviaintermolecular N—H...S hydrogen bonding between the amino H atoms and the thiocyanate and pyridine-4-carbothioamide S atoms. From this arrangement, channels are formed in which the methanol solvate molecules are embedded and linked to the host structure by intermolecular O—H...S and N—H...O hydrogen bonding.