Search results for "Benzene"

Spectrophotometric study on the thermodynamics of binding of α- and β-cyclodextrin towards some p-nitrobenzene derivativesElectronic supplementary in…

2003

Binding properties of native α- and β-cyclodextrin towards some nitrobenzene derivatives have been studied by means of UV-vis spectrophotometry. The former host is able to form complexes having 1 : 1 and 1 : 2 stoichiometric ratios with these guests, while only 1 : 1 complexes are detected with the latter host. A careful analysis of the thermodynamic parameters for complexation equilibria, under the perspective of the enthalpy–entropy compensation effect, reveals that binding abilities of the two different hosts are subject to different features.

Removal of TEX vapours from air in a peat biofilter: influence of inlet concentration and inlet load

2006

This paper presents the results of the study of the removal of toluene, ethylbenzene, and o-xylene (TEX) by biofiltration using a commercial peat as filter-bed material. Runs with a single organic compound in air, and with the mixture of TEX in air, were carried out for at least 55 days in laboratory-scale reactors inoculated with a conditioned culture. The influence of organic compound inlet load and of gas flow rate on the biofilter's performance was studied, including relatively high values of pollutant inlet concentration (up to 4.3 gC m−3 for ethylbenzene, 3.2 gC m−3 for toluene, and 2.7 gC m−3 for o-xylene). Results obtained show maximum elimination capacities of 65 gC m−3 h−1 for o-x…

Benzene, toluene, ethyl benzene and xylenes in ambient air and Pinus sylvestris L. needles: a comparative study between Belgium, Hungary and Latvia

2001

Abstract Concentrations of benzene, toluene, ethyl benzene and xylenes (BTEX) in ambient air and in 1 yr old Pinus sylvestris pine needles were monitored along a busy road, petrol station and rural area of Belgium, Hungary and Latvia in a 1 yr period. To test P. sylvestris as a possible biomonitor for the BTEX concentrations, samples were taken in the four seasons. As the distribution of data was not normal, the level of pollution on different sites and seasons was compared and evaluated by non-parametric tests. The measured air concentrations did not differ significantly from one season to another throughout the year. There were, however, differences between sampling places. The C2-alkylbe…

Lineare polyester mit carboxylendgruppen und deren bestimmung

1955

Durch Umsetzung von „alkoholischen” Bernsteinsaure-1,6-Hexandiol-Polyestern mit Bernsteinsaureanhydrid in Benzol werden kettenanaloge Polyester mit endstandigen Carboxylgruppen hergestellt. Die Titration dieser Carboxylgruppen ergibt Molgewichte bis ∼ 7 · 103. Mit Phenylisocyanat in indifferenten Losungsmitteln reagieren Polyesterdicarbonsauren unter Kettenverlangerung und Bildung von kettenstandigen Carbonsaureanhydridgruppen. Die Umsetzung der Polyester-dicarbonsauren in Phenylisocyanat ohne Verdunnungsmittel erfolgt kettenanalog unter Bildung von Carboxanilidendgruppen. Durch photometrische Anilinbestimmung nach der Hydrolyse konnen diese Endgruppen quantitativ bestimmt und Molgewichte b…

A Mixed-Ligand Approach for Spin-Crossover Modulation in a Linear FeII Coordination Polymer

2014

In this work, we present a family of Fe(II) coordination polymers of general formula [Fe(btzx)(3-3x)(btix)(3x)](ClO4)2 with interesting spin-crossover properties. These coordination polymers have been synthesized using chemical mixtures of two different but closely related ligands, 1,4-bis(tetrazol-1-ylmethyl)benzene (btzx) and 1,4-bis(triazol-1-ylmethyl)benzene (btix), and the effect of a gradual substitution of the ligand in the spin transition temperature has been investigated. Several chemical mixtures have been structurally characterized by X-ray powder diffraction indicating a clear critical amount in the composition of the mixture after which mixed phases rather than a single phase c…

Overview on oxidation mechanisms of organic compounds by TiO2 in heterogeneous photocatalysis

2012

This review provides the reader with a general overview on heterogeneous photocatalytic oxidation mechanisms in the presence of TiO2, with a special address to conversion of aliphatic and aromatic organic species. The aim was to clarify the steps of the photo-oxidation of the various classes of compounds and to relate them with the properties of the catalysts and the experimental conditions used. Reactions carried out to perform complete degradation and photocatalytic partial oxidations have been deeply discussed. Recent isotopic studies highlighted new reaction pathways concerning partial oxidation of alcohols to aldehyde and oxidation of benzene while EPR investigations confirmed that not…

Semicarbazides as gel forming agents for common solvents and liquid crystals

2006

This paper describes the synthesis of 14 new gelling agents with semicarbazide groups as H-bonding motifs and alkyl- and/or azobenzene side groups. They gel solvents like decaline, 1,2-dichlorobenzene and toluene and liquid crystalline mixtures. X-Ray structure analysis shows that the semicarbazides are connected by H-bonds, each molecule to four neighbours. As a result a ribbon is formed with a core of H-bonded semicarbazide groups and alkyl chains sticking to the side. IR measurements show an unchanged H-bonding motif in large crystals and in the gel fibres, even in LC-mixture. During heating the gel melts (rheology), while the H-bonding motif of the crystal disappears (IR and DSC measure…

2016

The title compound, C17H14ClN3O4, was prepared by the Huisgen reaction of 4-chloro-2-nitrobenzoyl chloride and 5-(4-propyloxyphenyl)tetrazole. The diphenyl-1,3,4-oxadiazole unit is nearly planar. The oxadiazole ring is inclined to the 4-chloro-2-nitrophenyl ring by 7.77 (8)°, and by 7.93 (8)° to the 4-propyloxyphenyl ring. The benzene rings are inclined to one another by 1.32 (7)°. The nitro group is twisted out of the plane of the benzene ring to which it is attached by 73.59 (16)°. The propoxy chain mean plane is inclined to the benzene ring to which it is attached by 4.46 (13)°. In the crystal, C—H...O and C—H...N hydrogen bonds connect the molecules, forming ribbons propagating along th…

Synthesis and characterisation of polymeric metal-ion carboxylates from benzene-1,3,5-tricarboxylic acid with Mn(II), Co(II) or Zn(II) and 2,2-bipyri…

2001

A total of 13 new co-ordination solids have been prepared of composition [Co(HBTC)(PHEN)(H2O)] (12), [Mn-3(BTC)(2)(PHEN)(3)] (13), [Mn(HBTC)(6)(H2O)] (14), [Mn(HBTC)(7)(H2O)] (15), [Zn-3(BTC)(2)(6)(3)(H2O)(3)]. 4H(2)O (16), [Zn-(HBTC)(6)(H2O)] (17), [Zn(H2BTC)(2)(6)] (18), [Zn(HBTC)(7)(H2O)] (19), [Zn(HBTC)(8)(H2O)] (20), [Zn-2(HBTC)(2)(9)(2)]. 2H(2)O (21), [Zn(HBTC)(10)(H2O)].H2O (22), [Co(HBTC)(10)(H2O)].H2O (23) and [Co(HBTC)(11)(H2O)] (24) 6 = pyridine-2-(1-methyl-1H-pyrazol-3-yl); 7 = pyridine-2-(1-methyl-4-bromo-1H-pyrazol-3-yl); 8 = pyridine-2-(1-methyl-4-nitro-1H-pyrazol-3-yl); 9 = pyridine-2-(1-methyl-5-trifluoromethyl-1H-pyrazol-3-yl); 10 = pyridine-2-(1-methyl-5-tert-butyl-1H-pyr…

ChemInform Abstract: An Efficient Synthesis of Rubin′s Aldehyde and Its Precursor 1,3,5-Tribromo-2,4,6-tris(dichloromethyl)benzene.

2011

The title compound (IV) serves as precursor of hexaethynylbenzenes and other [6]star compounds.