Desulfurization of thiophenic compounds is one of the important issues in refineries and environmental pollutions control. A bacterium was isolated from MTBE enriched soil was able to desulfurize of the thiophene. It was identified as Pseudomonas stutzeri based on phylogenetic analysis of 16S rRNA gene sequence. Desulfurization reactions from thiophene as the model of thiophenic compounds in aqueous phase by resting cells of this strain carried out and the concentration of thiophene was determined by UV-visible spectrophotometer in 230 nm wavelength. The results showed that the reduction of thiophene was 95% (from 12.4 mM to 0.3 mM) after 15 hours. Gas chromatography analysis showed the same results of thiophene desulfurization. Furthermore, The desulfurization activity of resting cells in a biphasic system containing crude oil by determination of released sulfate content turbidimetrically with BaCl2 was investigated.

Composite membranes with active layer of polyvinyl pyrrolidone/polyethylene glycol (PEG/PVP) blend with various mass ratios were manufactured on polyether solfune (PES) support layers and were applied in a pervaporative process for removal of thiophene from its mixture with normal heptane. The high-porous PES support membranes were prepared by Leob-Surirajan phase inversion technique, and their porosities were improved by adding hydrophilic additive of PVP to the polymer solution. The manufactured membranes were characterized using swelling test, SEM, and AFM imaging. The novel composite membranes exhibited unique features due to hydrogen bonding between the carbonyl groups of PVP and the hydroxyl groups of PEG as well as between the sections in the PEG structure in the range of 31-41 wt% PEG. The performances of the membranes under various operating conditions such as temperature, thiophene concentration, and PEG content in the active layer were investigated. The results indicates that the PVP/PEG composite membranes have superior performances over previously manufactured membrane for removal of thiophene in terms of enrichment factor and permeate flux. Further studies on PVP/ PEG composite membranes can provide helpful suggestions for pervaporative desulfurization of the refinery products.

The application of many hetero-aromatic compounds in pharmaceutical and dye industries make the theoretical study of their dipole moment (μ ) oscillator strength (f) and other photo-physical properties worthwhile. These properties determine the solubility of many compounds; predict the relationship between their structures, properties and performance. The f, μ , α , transition dipole moment (Δ μ ), vertical Excitation Energies (EE) and the frontier orbitals energy gap (Δ ELUMO-HOMO) of the optimized structures of 3, 4-diphenylthiophene (DPT); 3, 4-dicarboxylic-2, 5-diphenylthiophene (DCDPT); and benzo[b] thiophene (BT) were determined in solvents of different polarity functions (Δ P) by Time-Dependent Density Functional Theory, using Becke’ s three parameter with Lee-Yang-Parr modification and 6-31G* basis set theory (TD-DFT-B3LYP/6-31G*). The associated quantum chemical descriptors of Δ ELUMO-HOMO such as: Ionization Potential (IP) and global hardness (ƞ ) for the compounds were also determined with the same level of theory. The μ of the molecules increases with increasing Δ P, but highest for DCDPT. Bathochromic shifts associated with decreasing EE were recorded for the electronic transitions in DCDPT compare with those observed for DPT and BT. The IP and ƞ increased as Δ P increases, suggesting high stability of these compounds in polar solvents. The energy gaps, its associated parameters and positive Δ μ suggested strong activity of the molecules, with DCDPT being the highest. This is in reasonable agreement with the experimental results for the molecules particularly if the experimental uncertainties are considered.

The effect of the adsorbed thiophene (T) on the surface of (8,0) zigzag single walled boron nitride nanotubes (BNNTs) was studied using density functional theory calculations in the gas phase. Geometry optimizations were also carried out at the B3LYP/6-31G (d) level of theory. The Gaussian 09 suites of programs were used. The geometric optimization of (8, 0) BNNT-T was performed using the minimum energy criterion in six different configurations of the adsorbed thiophene on the nanotube. Our computer simulations have found that the preferred adsorption site of the molecule is at the end of the nanotube for the T component and all cases have physical interactions. The results showed an increase in polarity due to the proper distribution of electrons. It was also found that the reduction in global hardness, energy gap and electronic chemical potential due to thiophene adsorption leads to an increase in the stability of the (8,0) zigzag BNNT-T complex. In this study, natural bond analysis, global softness, ionization potential and electrophilicity index for nanotubes were calculated.

TS-2 is titanium silicate molecular sieve with MEL structure. This material has received considerable interest, because of its remarkable catalytic properties particularly in oxidation reactions under mild reaction conditions. In this paper a heterogeneous catalytic method for the oxidation of thiophene to cycloaddition of thiophene- S-oxide with thiophene -S,S-dioxide has been developed. When thiophene is treated with hydrogen peroxide in water in the presence of a large amount of TS-2, the compound 3a,4, 7, 7a-tetrahydro-4,7-epithiobenzo [b] –thiophene 1, 1,8-trioxide (I) is produced as a pure product, While in the presence of a little amount of catalyst, product (I) and 3a, 4, 7, 7a- tetrahydro-4 ,7- epithiobenzo [b] thiophene 1,8-dioxide were produced. The IR, NMR and Mass spectra of products were in good agreement with the literature data. The mechanism involves a Diels-Alder dimerization of thiophene-S-oxide followed by a further oxidation of non bridging vinylic sulfoxide in the dimmer.