• Journal of the Korean Chemical Society
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• v.58 no.4
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• pp.388-392
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• 2014

Benzothieno[2,3-d]pyrimidines (2,3,4) and benzothieno[3,2-e][1,3,4]triazolo[4,3-c] pyrimidines (5a-c) were synthesized from the precursor 2-amino-7-oxo-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile 1 by employing the conventional method as well as the microwave irradiation technique. The precursor 2-amino-3-cyanothiophene analogue 1 was synthesized by employing the well-known Gewald reaction. In the present work it has been found that the microwave supported syntheses are more efficient than the conventional classical heating methods. The structures of all the compounds were ascertained by spectral and analytical data.

• Bulletin of the Korean Chemical Society
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• v.10 no.3
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• pp.279-282
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• 1989

Two rhodium(I) complexes of the types [Rh(BPPF)(NBD)]$ClO_4$ (10) and [Rh(BPPF)$Cl]_2$ (11) (BPPF = 1,1'-bis(diphenylphosphino)-ferrocene) have been prepared and investigated as catalysts for the regioselective hydrogenation of polynuclear heteroaromatic nitrogen and sulfur compounds such as quinoline (1), acridine (2), phenanthridine (3), 7,8-benzoquinoline (4), benzothiophene (5), isoquinoline (6), indole (7), pyridine (8), and thiophene (9). Both complexes 10 and 11, except for the cases of indole (7) and mononuclear heteroaromatics 8-9, are very efficient in the selective reduction under quite mild hydrogenation conditions to give the corresponding saturated nitrogen and sulfur heterocyclic analogues of 1-6 in fast conversion rates and in excellent yields. Relative rate studies revealed that the reduction depends significantly on the steric and electronic effects of the substrates. Of the two complexes 10-11, the dimeric species 11 gives faster reaction rates in all cases studied.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.225-230
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• 2013

A new heteropolyanion-based ionic ($[Hmim]_5PMo_{10}V_2O_{40}$) was synthesized by the reaction of molybdovanadophosphoric acid ($H_5PMo_{10}O_{40}$) with N-methylimidazole. [$[Hmim]_5PMo_{10}V_2O_{40}$ showed a high catalytic activity in the oxidative desulfurization of sulfur-containing compounds in 1-methylimidazolium tetrafluoroborate ($[Hmim]BF_4$) ionic liquid using 30% aqueous $H_2O_2$ as the oxidant. The catalytic system was of high activity, simplified workup and flexible recyclability. The catalytic oxidation reactivity of sulfur-containing compounds decreased in the order dibenzothiophene (DBT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The influences of various parameters including reaction time (t) and temperature (T), catalyst dosage, and oxidant to sulfur molar ratio n(O)/n(S) on the desulfurization of model oil were investigated in details. 99.1% of DBT conversion in the model oil was achieved at atmospheric pressure under the optimal conditions: n(O)/n(S) = 4:1, $60^{\circ}C$, 100 min and molar ratio of catalyst to sulfur of 0.062. The ionic liquid can be recycled six times without significant decrease in activity.

• Environmental Engineering Research
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• v.19 no.3
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• pp.205-214
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• 2014

Petroleum a vital commodity affecting every aspect of 21st century. Toxicity and adverse effects of sulphur as catalyst in petroleum products is of great concern required development of techniques for desulphurization in compliance with the International standards. Installation of desulphurizing units costs over $200 million per unit placing economic burden on developing countries like Pakistan. Present study analysis of commercial fuels (station petrol and jet fuel JP8) on gas chromatography-mass spectrometry (GC-MS) identified sulphur concentration of 19.94 mg/L and 21.75 mg/L, respectively. This scenario urged the researcher to attempt synthesis of material that is likely to offer good adsorption capacity for sulphur. Following protocol of sol-gel method, transition metals (Ni, Cu, Zn) solution is gelated with tetraethoxysilane (TEOS; silica precursor) using glycerol. Fourier transform infrared spectroscopy (FTIR) spectra revealed bonding of Zn-O, Cu-O, and Ni-O by stretching vibrations at $468cm^{-1}$, $617cm^{-1}$, and $468cm^{-1}$, respectively. Thiophene and Benzothiophene mixed in n-heptane and benzene (4:1) for preparation of Model Fuels I and II, respectively. Each of silica based metal was applied as adsorbent in batch mode to assess the removal efficiency. Results demonstrated optimal desulphurization of more than 90% following efficacy order as Si-Ni > Si-Zn > Si-Cu based adsorbents. Proposed multilayered (Freundlich) adsorption mechanism follows ${\pi}$-complexation with pseudo secnd order kinetics.