1-(3-cyanophenyl)-3-(2-furoyl)thiourea

The title compound, C13H9N3O2S, was synthesized from furoyl isothiocyanate and 3-aminobenzonitrile in dry acetone. The thiourea group is in the thioamide form. The thiourea fragment makes dihedral angles of 3.91 (16) and 37.83 (12)degrees with the ketofuran group and the benzene ring, respectively. The molecular geometry is stabilized by N-H center dot center dot center dot O hydrogen bonds. In the crystal structure, centrosymmetrically related molecules are linked by two intermolecular N-H center dot center dot center dot S hydrogen bonds to form dimers.

3,3-Bis[(4-chlorophenyl)sulfanyl]-1-methylpiperidin-2-one

The piperidone ring in the title compound, C(18)H(17)Cl(2)NOS(2), has a distorted half-chair conformation. The S-bound benzene rings are approximately perpendicular to and splayed out of the mean plane through the piperidone ring [dihedral angles = 71.86 (13) and 46.94 (11)degrees]. In the crystal, C-H center dot center dot center dot O interactions link the molecules into [010] supramolecular chains with a helical topology. C-H center dot center dot center dot Cl and C-H center dot center dot center dot pi interactions are also present.

4-Methyl-3-(2-phenoxyacetyl)-5-phenyl-1,3,4-oxadiazinan-2-one

The 1,3,4-oxadiazinane ring in the title compound, C(18)H(18)N(2)O(4), is in a twisted boat conformation. The two carbonyl groups are orientated towards the same side of the molecule. The dihedral angle between the planes of the benzene rings is 76.6 (3)degrees. Molecules are sustained in the three-dimensional structure by a combination of C-H center dot center dot center dot O, C-H center dot center dot center dot pi and pi-pi [shortest centroid-centroid distance = 3.672 (6) angstrom] interactions.

1-(4-Bromophenyl)-2-ethylsulfinyl-2-(phenylselanyl)ethanone monohydrate

In the title hydrate, C(16)H(15)BrO(2)SSe center dot H(2)O, the sulfinyl O atom lies on the opposite side of the molecule to the Se and carbonyl O atoms. The benzene rings form a dihedral angle of 51.66 (17)degrees and are splayed with respect to each other. The observed conformation allows the water molecules to bridge sulfinyl O atoms via O-H center dot center dot center dot O hydrogen bonds, generating a linear supramolecular chain along the b axis; the chain is further stabilized by C-H center dot center dot center dot O contacts. The chains are held in place in the crystal structure by C center dot center dot center dot H center dot center dot center dot pi and C-Br center dot center dot center dot pi interactions.

Influence of Poly(Vinyl Alcohol) (PVA) on the Cyclic-Voltammetry Behavior of Single-Crystal Pt Surfaces in Aqueous H(2)SO(4)

In the present work we investigated the electrochemical behavior of PVA on polycrystalline Pt and single-crystal Pt electrodes. PVA hampered the characteristic hydrogen UPD and anion adsorption on all investigated surfaces, with the processes on Pt(110) being the most affected by the PVA presence. Several oxidation waves appeared as the potential was swept in the positive direction and the Pt(111) was found to be the most active for the oxidation processes. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615965] All rights reserved.

Imidazolium 4-aminobenzoate

In the title salt, C(3)H(5)N(2)(+) center dot C(7)H(6)NO(2)(-), the carboxylate group of the 4-aminobenzoate anion forms a dihedral angle of 13.23 (17)degrees with respect to the benzene ring. There are N-H center dot center dot center dot O hydrogen-bonding interactions between the anion and cation, and weak intermolecular C-H center dot center dot center dot O contacts with carboxylate O-atom acceptors of the 4-aminobenzoate anion result in extended three-dimensional R(4)(4)(22) and R(5)(6)(30) edge-fused rings along the [100], [010] and [001] directions.

(4-Hydroxy-2,5-dimethylphenyl)phenylmethanone

The title compound, C(15)H(14)O(2), was obtained by Friedel-Crafts acylation between 2,5-dimethylphenol and benzoyl chloride in the presence of aluminium chloride as a catalyst. The dihedral angle between the benzene rings is 61.95 (4)degrees. In the crystal, O-H center dot center dot center dot O hydrogen bonding and C-H center dot center dot center dot O weak interactions lead to polymeric C(6), C(8) and C(11) chains along the a, b and c-axis directions, respectively.

2-Bromo-2-methyl-N-p-tolylpropanamide

In the title molecule, C(11)H(14)BrNO, there is twist between the mean plane of the amide group and the benzene ring [C(=O)-N-C...;C torsion angle = -31.2 (5)degrees]. In the crystal, intermolecular N-H...O and weak C-H...O hydrogen bonds link molecules into chains along [100]. The methyl group H atoms are disordered over two sets of sites with equal occupancy.

Redetermination of 3-methylbenzoic acid

The asymmetric unit of the title compound, C(8)H(8)O(2), contains two crystallographically independent molecules, which form dimers linked by O center dot center dot center dot H-O hydrogen bonds. The benzene rings in the dimers are inclined at a dihedral angle of 7.30 (8)degrees and both methyl groups display rotational disorder. This redetermination results in a crystal structure with significantly higher precision than the original determination [Ellas & Garcia-Blanco (1963). Acta Cryst. 16, 434], in which the authors reported only the unit-cell parameters and space group, without any detailed information on the atomic arrangement. In the crystal, dimers are connected by weak C-H center dot center dot center dot O interactions, forming R(2)(2)(10) and R(4)(4)(18) rings along [110] and an infinite zigzag chain of dimers along the [001] direction also occurs.

2-Bromo-2-methyl-N-(4-nitrophenyl)propanamide

The title compound, C(10)H(11)BrN(2)O(3), exhibits a small twist between the amide residue and benzene ring [the C-N-C-C torsion angle = 12.7 (4)degrees]. The crystal structure is stabilized by weak N-H center dot center dot center dot O, C-H center dot center dot center dot Br and C-H center dot center dot center dot O interactions. These lead to supramolecular layers in the bc plane.

2-(2-Nitroanilino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carbonitrile

The title compound, C(16)H(15)N(3)O(2)S, was synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carbonitrile and o-fluoronitrobenzene. The thiophene and nitrophenyl rings and amino and carbonitrile groups are coplanar with a maximum deviation of 0.046 (2) angstrom and a dihedral angle of 0.92 (6)degrees between the rings. The cyclohepta ring adopts a chair conformation. Intramolecular N-H center dot center dot center dot O and C-H center dot center dot center dot S interactions occur. In the crystal, the molecules form layers that are linked by pi-pi stacking interactions between the thiophene and benzene rings [centroid-centroid distances = 3.7089 (12) and 3.6170 (12) angstrom].

Analysis of the emissions of volatile organic compounds from the compression ignition engine fueled by diesel-biodiesel blend and diesel oil using gas chromatography

This paper describes the procedures of the analysis Of Pollutant gases, as volatile organic compounds (benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene) emitted by engines, using high-resolution gas chromatography (HRGC). In a broad sense, CI engine burning diesel was compared with B10 and a drastic reduction was observed in the emissions of the aromatic compounds by using B10. Especially for benzene, the reduction of concentrations occurs on the level of about 19.5%. Although a concentration value below 1 mu g ml(-1) has been obtained, this reduction is extremely significant since benzene is a carcinogenic compound. (c) 2008 Elsevier Ltd. All rights reserved.

Application of high-resolution electrospray mass spectrometry for the elucidation of the disproportionation reaction of iodobenzene diacetate

Disproportionation reactions take place in solution of (diacetoxyiodo)benzene (DIB) in acetonitrile in the presence of water, giving iodine(V) and iodine(l) species. This redox reaction is accelerated by the presence of water and by increasing the temperature. Several species of the solution of DIB were identified by high-resolution ESI-MS/MS, which allowed the elucidation of the mechanisms of disproportionation for DIB in gas phase and in solution. Key species in the process are the dimers [PhI(CH)OlPh](+) at m/z 440.8864, [PhI(OAc)OlPh](+) at m/z 482.8947, and [PhI(O)(OAc)OlPh](+) at m/z 498.8887. (C) 2008 Elsevier B.V. All rights reserved.

Molecular Sieve Silica (MSS) Membranes for Gas Separation and Reaction Processes

Weakly branched silica films formed by the two-step sol-gel process allow for the formation of high selectivity membranes for gas separation. 29Si NMR and gas permeation showed that reduced crosslinking leads to He/CH4 selectivity improvement from 300 to 1000. Applied in membrane reactor for cyclohexane conversion to benzene, conversions were achieved at 14 fold higher than a conventional reactor at 250°C. Hydrothermal stability studies showed that carbon templating of silica is required for hydrothermally stable membranes. From our work it was shown that with correct application of chemistry, practical membrane systems can be built to suit gas separation (e. g. hydrogen fuel) and reactor systems.

Modification of MCM-41 by surface silylation with trimethylchlorosilane and adsorption study

Siliceous MCM-41 samples were modified by silylation using trimethylchlorosilane (TMCS). The surface coverage of functional groups was studied systematically in this work. The role of surface silanol groups during modification was evaluated using techniques of FTIR and Si-29 CP/MAS NMR. Adsorption of water and benzene on samples of various hydrophobicities was measured and compared. It was found that the maximum degree of surface attachments of trimethylsilyl (TMS) groups was about 85%, corresponding to the density of TMS groups of 1.9 per nm(2). The degree of silylation is found to linearly increase with increasing pre-outgassing temperature prior to silylation. A few types of silanol groups exist on MCM-41 surfaces, among which both free and geminal ones are responsible for active silylation. Results of water adsorption show that aluminosilicate MCM-41 materials are more or less hydrophilic, giving a type IV isotherm, similar to that of nitrogen adsorption, whereas siliceous MCM-41 are hydrophobic, exhibiting a type V adsorption isotherm. The fully silylated Si-MCM-41 samples are more hydrophobic giving a type III adsorption isotherm. Benzene adsorption on all MCM-41 samples shows type IV isotherms regardless of the surface chemistry. Capillary condensation occurs at a higher relative pressure for the silylated MCM-41 than that for the unsilylated sample, though the pore diameter was found reduced markedly by silylation. This is thought attributed to the diffusion constriction posed by the attached TMS groups. The results show that the surface chemistry plays an important role in water adsorption, whereas benzene adsorption is predominantly determined by the pore geometry of MCM-41.