(N(But)4)5H4PV6Mo6O40 as an efficient catalyst for the oxidative desulphurisation of gasoline J. Serb. Chem. Soc. 81 (1) 91–101 (2016) UDC 665.73+66.094.522.8:546.215:547.269.1 JSCS–4830 Original scientific paper 91 (N(But)4)5H4PV6Mo6O40 as an efficient catalyst for the oxidative desulphurisation of gasoline MOHAMMAD ALI REZVANI*, MOKHTAR ALI NIA ASLI, LIELA ABDOLLAHI and MINA OVEISI Department of Chemistry, Faculty of Science, University of Zanjan, 45371-38791 Zanjan, Iran (Received 2 February, revised 11 May, accepted 19 May 2015) Abstract: The oxidative desulphurization (ODS) of gasoline and model com- pounds that exist in gasoline with hydrogen peroxide using (N(But)4)5H4PV6Mo6O40 as a scavenger was studied. This Keggin-type poly- oxometalate was shown to be able to scavenge hydrogen sulphide and mer- captans in high yields. This system provides an efficient, convenient and practical method for scavenging sulphur compounds. This quaternary ammo- nium Keggin-type polyoxometalate ((N(But)4)5H4PV6Mo6O40) that has a lipo- philic cation can act as a phase transfer agent and better transfer the per- oxometal anion into the organic phase. The oxidation reactivity of the catalysts depends on the type of the counter-cation: ((C4H9)4N) + > NH4 + > K+. Keywords: Keggin-type polyoxometalate; counter-cation; mercaptan; gasoline; demercaptanization. INTRODUCTION In the past decade, clean fuels research, including demercaptanization and desulphurization, has become an important subject of environmental catalysis studies worldwide.1–5 Mercaptans are a kind of organic sulphide that widely exist in petroleum products. They cause foul odours and deteriorate the finished products. Due to their acidity, mercaptans are corrosive to metals, which is harm- ful to storage and usage of oil products.5–7 Therefore, it is necessary to remove them, either by transforming them to innocuous disulphides or by their extract- ion.7–11 In continuation of on-going research on the syntheses and application of polyoxometalate in organic reactions,12–21 herein, the applicability of quaternary ammonium Keggin-type molybdovanadophosphate ((N(But)4)5H4PV6Mo6O40) for the efficient desulphurization of gasoline in the preparation of ultra-clean fuels is reported. This quaternary ammonium Keggin-type molybdovanadophos- * Corresponding author. E-mail: marezvani2010@gmail.com doi: 10.2298/JSC150202040A 92 ALI REZVANI et al. phate, ((N(But)4)5H4PV6Mo6O40), that has a lipophilic cation can act as a phase transfer agent and transfer the peroxometal anion into the organic phase. The cat- alytic function of heteropolyacids (HPAs) has attracted much attention because of their uncommon ability to accept an electron without deformation of their structure or reversible reduction.12–14 Keggin-type polyoxoanions have been widely studied as homogeneous and heterogeneous catalyst for the oxidation of organic compounds, whereas the application of Wells–Dawson type polyoxo- anions is mostly limited to homogeneous or gas phase applications and only a few investigations have demonstrated catalytic activity in the heterogeneous form.14–17 Generally, Keggin structures show more acidity and catalytic activity among the heteropolyacids.14 These solid acids are usually insoluble in non-polar solvents but highly soluble in polar ones. They can be used in bulk or supported forms in both homogeneous and heterogeneous systems.19 Further catalytically important subclasses of the Keggin compounds are the mixed-addenda vanadium-substituted HPAs with the general formula H3+nPM12–nVnO40 (M = = Mo or W; n = 1 to 6). In fact, Vn+ is the most strongly oxidizing element and can be readily reduced to V(n–1)+ with the concomitant oxidation of an organic substrate. The introduction of Vn+ into the Keggin framework shifts its catalytic activity from acid-dominated to redox-dominated. Various oxidants have been used in oxidative desulfurization (ODS), such as NO2, O3, H2O2 and solid oxid- izing agents.11 Among these oxidants, H2O2 is mostly chosen as an oxidant, as only water is produced as a by-product. Peracids produced in situ from organic acid catalysts and H2O2 were reported to be very effective for the rapid oxidation of sulphur compounds in fuel oils under mild conditions. The catalytic activity of ((N(But)4)5H4PV6Mo6O40) was tested on the oxidative desulphurization of gaso- line and model sulphur compounds that exist in gasoline, i.e., benzothiophene (BT) and thiophene (T), with formic acid/hydrogen peroxide as the oxidizing reagent. The catalyst could be easily separated and reused at the end of the reaction without significant loss in its catalytic activity, which suggests that the catalyst is stable under different conditions. EXPERIMENTAL All reagents and solvents used in this work were available commercially and used as received, unless otherwise indicated. The model compounds and chemicals, including thio- phene (T) and benzothiophene (BT), solvent (n-heptane) for the experiments and analysis and hydrogen peroxide (30 vol. %) were obtained from Aldrich. Typical actual gasoline (density 0.7918 g mL-1 at 15 °C, total sulphur content 0.391 wt. %) was used and details of its properties are given in Table I. Preparation of the catalysts Several heteropolyoxometalate catalysts: (NH4)5H4PV6W6O40, (NH4)6HPV4W8O40 and (NH4)5H4PV6Mo6O40, etc., used for comparison, were prepared according to literature (N(But)4)5H4PV6Mo6O40 AS CATALYST FOR DESULFURIZATION OF GASOLINE 93 procedures.17,22 Details of the preparation of the catalysts are given in the Supplementary material to this paper. TABLE I. Properties of the examined gasoline before and after oxidative desulphurization, ODS, by (N(But)4)5H4PV6Mo6O40; IBP – initial boiling point; FBP – final boiling point After ODSa Before ODSMethod Unit Properties of gasoline Entry 0.7912 0.7918 ASTM D 1298g mL-1 Density by hydrometer at 15 °C1 0.014 0.391 ASTM D 4294wt.% Total sulphur by X-ray analysis2 3 39 ASTM D 3227ppm Mercaptans 3 14 16 ASTM D 3230ptb Salt 4 Nil. Nil. ASTM D 4006vol. % Water content by distillation 5 43.6 43.9 ASTM D 86 C IBP* Distillation 6 208.1 208.5 FBP# 67.1 68.3 vol. % 10 112.2 114.2 50 183.6 184.3 90 205.8 206.1 95 aCondition for desulphurization: 20 mL of gasoline, 0.1 g catalyst, 2 mL oxidant, 10 mL of extraction solvent, time = 1 h, and temperature = 40 °C Catalyst characterization The chemical characterization of the prepared catalysts was accomplished by means of elemental analysis and IR spectroscopy. Elemental analysis results were obtained by Integra XL inductively coupled plasma spectrometer. The Fourier transform infrared (FTIR) spectra of the solid samples were recorded in KBr pellets on a Thermo-Nicolet-is 10 instrument in the wavenumber range 400–4000 cm-1. Catalytic tests Oxidative desulphurization of simulated gasoline using the formic acid/H2O2 system. Some typical thiophenes and benzothiophenes, which represent easy and hard to remove sul- phur species in gasoline, were selected to evaluate the catalysts and the reactivity of the thiophenes and benzothiophenes in the oxidation reaction. Stock solutions of the model sul- phur compound were made by dissolving T or BT in n-heptane to give a final sulphur concentration of 500 ppm. Then, performic acid (1:1 mixture of formic acid and hydrogen peroxide) was added to 5 mL of a stock solution. The resulting solution was heated to the required temperature (0–50 °C) in a water bath under stirring. After attaining the desired temperature, a sample was removed and catalyst was added to the remaining solution to initiate the reaction. Stirring was continued for a further 1 h. After cooling to room tempe- rature, the biphasic mixture was separated by decantation and the organic phase saved for analysis. Oxidative desulphurization of gasoline using the formic acid/H2O2 system. In the same manner as for the oxidation of the model sulphur compounds but using actual gasoline (sulphur 391 ppm) except 20 mL of gasoline was used. After the oxidation was finished, the mixture was cooled down to room temperature and 10 mL acetonitrile (MeCN) was added to extract the oxidized sulphur compounds. The observed biphasic system was separated by decantation and weighed to calculate % recovery of gasoline. (Through three times reaction: 98, 97 and 95 %). 94 ALI REZVANI et al. Determination of the total sulphur and mercaptan sulphur contents Determination of the contents of total sulphur and mercaptan sulphur in the gasoline and simulated gasoline samples before and after reaction were determined by X-ray fluorescence spectroscopy using a Tanaka RX-360 SH X-ray fluorescence spectrometer following the ASTM D-4294 and ASTM D-3227 standard test methods. Details of the ASTM D-4294 method are discussed in the Supplementary material to this paper. Recycling of the catalyst At the end of the oxidative desulphurization of the model sulphur compounds and gasoline, the catalyst was filtered off and washed with dichloromethane. In order to determine whether the catalyst would succumb to poisoning and lose its catalytic activity during the reaction, the reusability of the catalyst was investigated. For this purpose, the desulphurization reaction of gasoline and model compounds was performed in the presence of fresh and recovered catalyst. RESULT AND DISCUSSION Catalysis characterization The chemical compositions of the vanadium-containing catalysts are given in Table II. TABLE II. Characteristic IR vibrations (as / cm–1) and elemental analysis data for the vanadium-containing polyoxmetalate catalysts Composition, % Mo–Oc–MoMo–Ob–Mo Mo–Od P–Oa Catalyst V Mo P Cal. Found Cal. FoundCal.Found 2.13 3.35 44.1 46.51.291.26741 875 954 1053 H4PMo11VO40 4.31 6.91 40.4 40.61.311.33740 873 952 1052 H5PMo10V2O40 17.4 16.3 32.7 39.21.761.75732 865 947 1042 H9PV6Mo6O40 FTIR spectroscopy is an extensively used tool for the characterization of polyoxometalates as this technique provides finger printing in the structural elu- cidation of the Keggin structure.12,14 The FTIR spectra of different polyoxomet- alates salts showed the common characteristic absorption peaks ranging from 500 to 1100 cm–1 that correspond to the oxometalate anion configurations (Table II). The peak ranges (Table II) characteristic for POM are: 730–765 cm–1, octa- hedral corner sharing M–Oc–M; 860–885 cm–1, octahedral bridge/edge sharing M–Ob–M; 940–965 cm–1, terminal M–O and 1040–1070 cm–1, P–O configur- ations.12,14 These configurations collectively account for Keggin type polyoxo- metalates. The oxygen atoms of the Keggin structure can be subdivided into four different types, i.e., Oa, inner oxygen; Oc, corner-sharing oxygen; Ob, edge-shar- ing oxygen and Od, terminal oxygen. These exhibit four well-defined infrared bands that can be applied for the identification and discrimination of different heteropolyacid catalysts. The four classes of oxygen atoms can be described as follows: the central oxygen X–Oa establishes a connection between the central heteroatom of the XO4 tetrahedron and the transition metal atoms of a trimetallic (N(But)4)5H4PV6Mo6O40 AS CATALYST FOR DESULFURIZATION OF GASOLINE 95 MO3 structure. The M–Ob–M oxygen atoms connect two M3O13 units by corner sharing. Furthermore, M–Oc–M oxygen links two transition metal atoms by edge sharing of two MO6 units and finally the terminal oxygen atom M–Od binds to only one transition metal atom.8,14,22 Effect of the catalyst structure on the oxidative desulphurization The effect of the nature of the catalyst on the oxidative desulphurization of gasoline using formic acid/H2O2 as the oxidant is shown in Tables III and IV. The amount of each catalyst was constant throughout the series. The Keggin type polyoxometalate catalyst (N(But)4)5H4PV6Mo6O40 was a very active system for the oxidation of gasoline, while the other studied polyoxometalates systems were much less active. This system ((N(But)4)5H4PV6Mo6O40) with a phase transfer or emulsion catalyst comprising a quaternary ammonium salt-based polyoxomet- alate was shown to be a very active system for oxidative desulphurization of gasoline. This quaternary ammonium Keggin-type molybdovanadophosphate ((N(But)4)5H4PV6Mo6O40) that has a lipophilic cation could better act as phase transfer agent and better transfer the peroxometal anion into the organic phase. That is, the oxidation reactivity of the catalysts depends on the type of counter- cation: ((C4H9)4N)+ > NH4+ > K+. It was shown that the order of the oxidation reactivity of the catalyst in the presence of hydrogen peroxide/formic acid was: ((N(But)4)5H4PV6Mo6O40 > (N(But)4)4HPMo10V2O40 > (NH4)5H4PV6Mo6O40 > K5H4PV6Mo6O40 >H5PMo10V2O40 > H4PMo11VO40. From the result of Table III, the catalytic activity of R3+nPM12–nVnO40 (R = H, K, NH4 or N(But)4; M = Mo or W; n = 0 to 6) was in the order of n = 6 >…> n = 0. The results show that the catalytic activity of ((N(But)4)5H4PV6Mo6O40 was much higher than those of the other polyoxometalates. In fact, Vn+ is the most strongly oxidizing element and can be readily reduced to V(n–1)+ with the concomitant oxidation of an organic substrate. The introduction of Vn+ into the Keggin framework shifts the catalytic activity from acid-dominated to redox-dominated. TABLE III. Effect of different catalysts on the ODS of gasoline and simulated gasoline conversion; conditions for desulphurization: 5 mL of model gasoline (200 ppm S) or 20 mL of gasoline, 0.1 mmol catalyst, 2 mL performic acid, 10 mL extraction solvent, time 1 h and temperature 40 °C Entry Catalyst Ratio Conversion, % BT/catalyst Oxidant/BT Thiophene BT Gasoline 1 (N(But)4)5H4PV6Mo6O40 100 10 98 97 97 2 (NH4)5H4PV6Mo6O40 30 10 92 90 91 3 K5H4PV6Mo6O40 30 15 86 85 85 4 H5PMo10V2O40 30 15 85 85 84 5 (N(But)4)4HPMo10V2O40 50 10 94 94 94 6 H4PMo11VO40 20 15 84 83 83 7 H3PMo12O40 20 15 81 81 81 96 ALI REZVANI et al. TABLE IV. Effect of different catalysts on the ODS of gasoline; conditions for desulphur- ization: 20 mL of gasoline, 0.1 g catalyst, 2 mL oxidant, 10 mL of extraction solvent, time 1 h, temperature 40 °C Entry Catalyst Total sulphur removed, % Mercaptans removed, % With H2O2 Without H2O2 With H2O2 Without H2O2 1 (N(But)4)5H4PV6Mo6O40 97 45 94 38 2 (NH4)5H4PV6Mo6O40 91 40 89 30 3 K5H4PV6Mo6O40 85 38 84 33 4 H5PMo10V2O40 84 37 82 31 5 (N(But)4)4HPMo10V2O40 94 41 90 36 6 H4PMo11VO40 83 34 81 30 7 H3PMo12O40 81 33 80 30 8 N(But)4Br 33 16 34 15 9 None 22 – 21 – Effect of catalyst dosage Another factor that should be considered is the catalyst dosage. It was found that the catalyst dosage had a marked influence on the process efficiency (Table V). Under otherwise identical conditions, without catalyst, 24 % of the thiophene and 23 % of the benzothiophene were removed from the n-heptane phase and 23 % of the sulphur from actual gasoline in 60 min by oxidation. The percent conver- sions in actual gasoline in the presence of ((N(But)4)5H4PV6Mo6O40 were found to be 64, 87.5 and 97 %, corresponding to catalyst amount of 0.06, 0.08 and 0.1 g, respectively. Thus, the desulfurization efficiency increased rapidly with inc- reasing catalyst dosage. TABLE V. Effect of catalyst dosage on the ODS of gasoline and simulated gasoline conver- sion; conditions for desulphurization: 20 mL of gasoline, catalyst, (N(But)4)5H4PV6Mo6O40, 2 mL oxidant, 10 mL of extraction solvent, time 1 h, temperature 40 °C Entry Amount of catalyst, g Reactant Thiophene Benzothiophene Actual gasoline 1 0 24 23 22 2 0.02 38 36 35 3 0.04 45 43 42 4 0.06 67 65 64 5 0.08 89 87 87 6 0.1 98 97 97 7 0.11 98 97 97 8 0.12 98 97 97 Influence of quaternary ammonium cation on the catalytic activity Countercation with quaternary ammonium salts with lipophilic cation could act as a phase transfer agent and could transfer the peroxometal anion into the organic phase. An amphiphilic catalyst with a proper quaternary ammonium cat- (N(But)4)5H4PV6Mo6O40 AS CATALYST FOR DESULFURIZATION OF GASOLINE 97 ion could form metastable emulsion droplets in gasoline with an aqueous H2O2 solution, demonstrating high oxidative activity, and could be separated after reac- tion through centrifugation. For example, [N(C4H9)4]+ is a proper quaternary ammonium cation (Tables III–V). Other cations were tested and it was found that [N(C4H9)4]+ forms metastable emulsion droplets in gasoline more readily than do NH4+ and K+. Effect of temperature on the oxidative desulfurization of gasoline or simulated gasoline The reaction was carried out at different temperatures under the same con- ditions using ((N(But)4)5H4PV6Mo6O40 as the catalyst and formic acid/H2O2 as the oxidant. The results, given in Table VI, show that yields of the products are a function of temperature. The percent conversions of sulphur in the solutions of the model compounds and in actual gasoline increased with temperature and time. The percent conversion of sulphur in the simulated fuel at 40 °C was higher than that at 30 °C. At 40 °C in 60 min, 97 % conversion of sulphur was obtained. TABLE VI. Effect of different temperatures on the ODS of gasoline and simulated gasoline conversion; conditions for desulphurization: 10mL simulated gasoline or 20 mL of gasoline, 0.1 g catalyst, 2 mL oxidant, 10 mL of extraction solvent, time 1 h Entry Temperature, °C Reactant Thiophene Benzothiophene Actual gasoline 1 25 82 81 80 2 30 86 85 84 3 35 90 88 87 4 40 98 97 97 5 45 98 97 97 6 50 97 96 97 Effect of different oxidation system on the oxidative desulphurization of gasoline Effect of oxidation system on the oxidative desulfurization of gasoline was studied (Table VII). Hydrogen peroxide, KMnO4 and K2Cr2O5 were selected as oxidizing agents, which were used in the presence of an organic or inorganic acid, i.e., formic acid, acetic acid, oxalic acid, benzoic acid, H2SO4 and H2CO3 to acidify the system. The results in Table VII showed that in the presence of the inorganic acids, H2SO4 and H2CO3, the oxidation reactivity was lower than in the presence of the organic acids. In actual gasoline, H2SO4 and H2CO3 cannot dissolve; thus, the sulphur removal from gasoline by inorganic acid/H2O2 was lower than the removal by the organic acid/H2O2 systems. Effect of the amount of formic acid Effect of the amount of formic acid on the oxidative desulphurization of different sulphur compounds was studied and the results are given in Table VIII. In 98 ALI REZVANI et al. TABLE VII. Effect of different oxidation system on the ODS of gasoline; conditions for desulphurization: 20 mL of gasoline, 0.1 g ((N(But)4)5H4PV6Mo6O40, 2 mL oxidant, 10 mL of extraction solvent, time 1 h, temperature 40 °C Total sulphur removed, % Mercaptans removed, % Acid Oxidant Entry 97 94 Formic acid H2O2 1 97 93 Acetic acid H2O2 2 92 89 Oxalic acid H2O2 3 91 87 Benzoic acidH2O2 4 79 80 H2SO4 H2O2 5 78 78 H2CO3 H2O2 6 85 86 – H2O2 7 74 75 Formic acid KMnO4 8 73 74 Oxalic acid KMnO4 9 74 73 H2SO4 KMnO4 10 76 76 – KMnO4 11 74 76 Formic acid K2Cr2O5 12 74 73 Oxalic acid K2Cr2O5 13 73 74 H2SO4 K2Cr2O5 14 76 77 – K2Cr2O5 15 TABLE VIII. Effect of formic acid amount on the ODS of gasoline and simulated gasoline conversion; conditions for the desulphurization: 20 mL of gasoline or 10 mL simulated gasoline, 2 mL H2O2/formic acid as oxidant, 0.1 g (N(But)4)5H4PV6Mo6O40, 2 mL oxidant, 10 mL of extraction solvent, time 1 h Entry Formic acid/sulphur compound mole ratio Reactant Thiophene Benzothiophene Actual gasoline 1 0.25 56 54 53 2 0.5 69 67 66 3 0.75 86 85 85 4 1.0 98 97 97 5 1.25 97 96 95 6 1.5 97 95 95 the formic acid catalyzed reaction, the formic acid can interact with sulphur without any steric hindrance from the alkyl groups. Therefore, the reactivity trend obtained in the formic acid catalyzed reactions reflects the intrinsic oxid- ation reactivity of the thiophenes. The % sulphur removal of the simulated gas oil increased with increasing formic acid. It could be seen that a formic acid/H2O2 mole ratio of 1.0 (98 % conversion of thiophene) was better than the other mole ratios. Therefore, in all other experiments, this formic acid/thiophene mole ratio was used. In gasoline mixed with formic acid/H2O2 (performic acid), the oxi- dative reaction occurred below 50 °C under atmospheric pressure. This was fol- lowed by liquid//liquid extraction to obtain a gasoline with a low sulphur and an extract with a high sulphur content. Finally, the low sulphur gasoline may require additional treatment. The extraction solvent was then removed from the extract (N(But)4)5H4PV6Mo6O40 AS CATALYST FOR DESULFURIZATION OF GASOLINE 99 for reuse and the concentrated extract was made available for further processing to remove sulphur and to produce hydrocarbons. Reusability of the catalyst The catalyst from the first desulphurization was recovered from the reaction mixture by filtration, washed with dichloromethane and used for the next desul- phurization. This was repeated a further three times. The results of the effect- iveness of the reused catalyst are given in Table IX, from which it could be seen that the catalyst largely retained its activity on recycling. TABLE IX. Reuse of the catalyst on the ODS of thiophene; conditions for desulphurization: 5 mL of model gasoline (200 ppm S), 0.1 mmol (N(But)4)5H4PV6Mo6O40, 2 mL formic acid/H2O2, 10 mL extraction solvent, time 1 h, temperature 40 °C Isolated yield, % Entry 98 1 96 2 96 3 95 4 94 5 General remark concerning the desulfurization process A model gasoline was made by adding T and BT into n-heptane solvent, with a total sulphur concentration of 200 mg L–1. The organic sulphur com- pounds were mixed with formic acid/H2O2 and ((N(But)4)5H4PV6Mo6O40 and then the oxidation reaction occurred at 40 °C under atmospheric pressure. This was followed by a liquid extraction (acetonitrile) to obtain gasoline with a low sulphur content. Many oxidizing agents have been reported in ODS processes, whereby H2O2 was the main one. Hydrogen peroxide is one of the most attract- ive oxidants, mainly because it is environmentally clean and easily handled. Hyd- rogen peroxide first rapidly reacts with an organic acid to generate peracid. It should be noted that during the ODS process, H2O2 was used in the presence of formic acid as oxidants because formic acid, as an organic acid, reacts with H2O2 to in situ produce peracid, which can efficiency convert organic sulphur to sul- phones without the formation of a substantial amount of residual product. The role of the metal atoms in ((N(But)4)5H4PV6Mo6O40, M = V or Mo, was to form peroxo-metal species, which are able to activate the H2O2 and peracid molecules. ((N(But)4)5H4PV6Mo6O40 accepted the active oxygen from the oxidant H2O2 to form new oxoperoxo species mediates. The cation with the carbon chain trans- ferred oxoperoxo species to the substrates (T or BT) and enabled the oxidation reaction to be accomplished completely. 100 ALI REZVANI et al. CONCLUSIONS The system with ((N(But)4)5H4PV6Mo6O40), a phase transfer or emulsion catalyst comprising a quaternary ammonium salt-based polyoxometalate, was shown to be a very active system for the oxidative desulphurization of gasoline. This quaternary ammonium Keggin-type molybdovanadophosphate ((N(But)4)5H4PV6Mo6O40), which has a lipophilic cation, can act as phase trans- fer agent and transfer the peroxometal anion into the organic phase. That is, the oxidation reactivities of the catalysts depend on the type of countercation: ((C4H9)4N)+ > NH4+ > K+. In the present work, the efficient oxidative desul- phurization of gasoline and simulated gasoline using the formic acid/hydrogen peroxide (peracid) system was reported. The system provides an efficient, con- venient and practical method for scavenging sulphur compounds in gasoline. SUPPLEMENTARY MATERIAL The preparation of the V-containing catalysts and a discussion of the ASTM D-4294 standard method for the determination of sulphur compounds in gasoline are available electro- nically from http://www.shd.org.rs/JSCS/, or from the corresponding authors on request. И З В О Д (N(But)4)5H4PV6Mo6O40 КАО ЕФИКАСАН КАТАЛИЗАТОР ЗА ОКСИДАТИВНУ ДЕСУЛФУРИЗАЦИЈУ БЕНЗИНА MOHAMMAD ALI REZVANI, MOKHTAR ALI NIA ASLI, LIELA ABDOLLAHI и MINA OVEISI Department of Chemistry, Faculty of Science, University of Zanjan, 45371-38791 Zanjan, Iran Испитивана је оксидативна десулфуризација (ОSD) бензина и модел једињења која постоје у бензину са водник-пероксидом у присуству (N(But)4)5H4PV6Mo6O40. Показано је да ово полиоксометалатно једињење Кегиновог типа може да уклони водоник-сулфид и меркаптане у виском приносу. Овај систем омогућава ефикасан, погодан и практичан метод за елиминацију сумпорних једињења. Квартернерни амонијум-полиоксометалат Кегиновог типа, (N(But)4)5H4PV6Mo6O40, који има липофилни катјон има боље каракте- рстике као агенс за фазни трансфер и може боље да преведе пероксометални анјон у органску фазу. Тачније, оксидативна реактивност катализатора зависи од типа контра- катјона: ((C4H9)4N) + > NH4 + > K+. (Примљено 2. фебруара 2014, ревидирано11. маја, прихваћено 19. маја 2015) REFERENCES 1. G. F. Zhang, F. L. Yu, R. Wang, Petrol. Coal 51 (2009) 196 2. I. V. Babich, J. A. Moulijn, Fuel 82 (2003) 607 3. J. M. Campos, M. C. Sanchez, P. Presas, J. L. G. Fierro, J. Chem. Technol. Biotechnol. 85 (2010) 879 4. P. S. Tam, J. R. Kittrell, J. W. Eldridge, Ind. Eng. Chem. Res. 29 (1990) 321 5. D. Wang, E. W. Qian, H. Amano, K. Okata, A. Ishihara, T. Kabe, Appl. Catal., A 253 (2003) 91 6. S. Otsuki, T. Nonaka, W. Qian, A. Ishihara, T. Kabe, Bull. Chem. Soc. Jpn. 31 (1998) 1939 (N(But)4)5H4PV6Mo6O40 AS CATALYST FOR DESULFURIZATION OF GASOLINE 101 7. D. Wang, E. W. Qian, H. 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