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1

Water effect on oxidative desulphurization process of straight-run kerosene fraction

Pyshyev S., Bratychak M., Hayvanovych V., Paniv P., Wacławek W.

Ecological Chemistry and Engineering. S

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2013

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Vol. 20, nr 1

55-68

EN

Sulphur dioxide obtained during fuels burning in combustion engines is one of the main pollutants. In diesel oils and gasolines the sulphur content must be 5-10 ppm and in jet fuels - 300-3000 ppm. However the production of hydrofined jet fuel is problematic. The reason is deterioration of fuel stability and antioxygenic properties. The oxidative desulphurization of straight-run kerosene was investigated. This method combines oxidation by atmospheric oxygen of sulphur compounds under increased temperature and pressure in the presence of water in the reaction medium, and removal of oxidized sulphur compounds from the oxidation-treated fuel via rectification. It was showed that water partially extracts from the hydrocarbon medium acidic compounds, formed in the beginning stage of oxidation, dissociation of which leads to the formation in water acidic medium. As a result, a pathway of the hydroperoxides decomposition partially changes from the formation of carbonic acids and oxyacids to the formation of alcohols, phenols and alkylphenols, which displayed an inhibitory effect in hydrocarbon oxidation. It was assumed that an inhibitory effect of water, in addition to the creation reverse micelles with peroxides and complexes with free radicals, caused by oxidation products created in the beginning stage of oxidation. The effect of water/kerosene ratio on the oxidative desulphurization of straight-run kerosene fraction has been examined. It was found that water improves process selectivity with insignificant influence on the degree of sulphur recovery. The optimum value of water/kerosene ratio for the fuel containing 0.15% mass of sulphuric compounds has been determined.

PL

Ditlenek siarki powstający podczas spalania paliw w silnikach spalinowych jest jednym z głównych zanieczyszczeń. W olejach napędowych i benzynie zawartość siarki powinna mieścić się w granicach 5-10 ppm, a w paliwach do silników odrzutowych - 300-3000 ppm. Jednak wykorzystanie paliwa lotniczego modyfikowanego metodą hydrorafinacji jest problematyczne ze względu na pogorszenie stabilności i właściwości utleniających takich paliw. Badano odsiarczanie frakcji naftowej metodą utleniania. Metoda ta łączy utlenianie tlenem atmosferycznym związków siarki przy podwyższonej temperaturze i ciśnieniu, w obecności wody w środowisku reakcji, oraz usunięcie utlenionych związków siarki z paliwa na drodze rektyfikacji. Wykazano, że woda częściowo wyodrębnia ze środowiska węglowodorowego kwaśne związki utworzone w początkowym etapie utleniania. Szlak rozkładu hydronadtlenków zmienia się częściowo z tworzenia kwasów karboksylowych i kwasów tlenowych na powstawanie alkoholi, fenoli i alkilofenoli, które okazały się inhibitorem utleniania węglowodorów. Założono, że hamujący wpływ wody, oprócz tworzenia miceli odwróconej z nadtlenkami i kompleksów z wolnymi rodnikami, spowodowany był produktami utleniania utworzonymi w początkowym etapie reakcji. Badano wpływ proporcji wody i frakcji naftowej na odsiarczanie oksydacyjne. Stwierdzono, że woda poprawia selektywność procesu i ma niewielki wpływ na stopień odzysku siarki. Ustalono optymalną wartość stosunku woda/frakcja naftowa dla paliwa zawierającego 0,15% masowych związków siarki.

2

Oxidative desulfurization of synthetic diesel oil by oxidation/adsorption continuous flow process

Fabiś G., Lewandowski M., Sarbak Z., Czajkowska S.

Polish Journal of Applied Chemistry

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2010

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Vol. 54, nr 1-4

41-48

EN

Catalytic oxidative desulfurization (ODS) of a synthetic diesel oil was studied in the presence of metal containing (Ti. V. Nb. Ta) MCM-41 catalysts. The effects of reaction temperature, reaction time, oxidant to sulfur molar ratio and sulfur concentration on the sulfur removal were investigated. The obtained results indicated that metal containing MCM-41 type mesoporous molecular sieves are able to catalyze the continuous selective oxidation of the most refractory sulfur compounds such as 4.6-dimethyldibenzothiophene.

3

The oxidation of 1-chloro-3-alkylthio-2-propanols and 1-alkylthio-2,3-epoxypropanes to sulfoxides and sulfones

Chlebicki J.

Polish Journal of Applied Chemistry

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2004

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Vol. 48, nr 1-2

23-31

EN

1-Chloro-3-alkylsulfinyl-2-propanols, 1-chloro-3-alkylsulfonyl-2-propanols and 1-alkylsulfinyl-2,3-epoxypropanes were obtained in the oxidation reaction of the respective sulfides using such oxidants as 3-chloroperbenzoic acid, NaIO4 and H2O2. The following parameters of the reaction were investigated - time, temperature and the molar ratio of oxidant and sulphide. It was found that the highest yield of sulfoxides was obtained when NaIO4 or H2O2 was used under neutral pH. The oxidation of sulfides with H2O2 under acidic conditions leads to 1-chloro-3-alkylsufonyl-2-propanols with almost quantitative yield.

PL

W reakcji utleniania odpowiednich sulfidów otrzymano 1-chloro-3-alkilosulfinylo-2--propanole i 1-chloro-3-alkilosulfonylo-2-propanole za pomocą takich utleniaczy jak: kwas 3-chloronadbenzoesowy, NaIO4 i H2O2. Zbadano warunki prowadzenia utleniania, takie jak temperatura i czas reakcji, a przede wszystkim stosunek molowy utleniacza do sulfidu. Stwierdzono, że największą wydajność sulfotlenków można uzyskać przy użyciu NaIO4 lub H2O2 w środowisku obojętnym. Utlenianie badanych sulfidów przy użyciu H2O2 w środowisku kwaśnym prowadzi do otrzymania z prawie ilościową wydajnością tylko 1-chloro-3--alkilosulfonylo-2-propanoli.

4

Postępy w stereoselektywnym utlenianiu sulfidów

Skarżewski J., Ostrycharz E.

Wiadomości Chemiczne

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2000

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[Z] 54, 9-10

725-758

EN

The preparation of optically active sulfoxides, useful chiral auxiliaries and synthetic building blocks is reviewed. Beginning with the progresses in the non-oxidative synthesis of chiral sulfoxides, the main part of the survey is devoted to the advances in stereoselective oxidation of the easily available prochiral sulfides. Firstly, the diastereoselective oxidation of sulfides containing other chiral center is discussed. Remarkable selectivities were obtained in the oxidation with MCPBA, t-BuOCl, and (NaOCl, cat. TEMPO). In the next part the enantioselective oxidation processes are considered. The material is organized according to the character of the oxidant: chiral-stoichiometric methods and chiral catalytic methods. Among stoichiometric chiral oxidants, some of the most important are the Davis oxaziridines. An essential improvement in enantioselectivity was gained by the application of N-(phenylsulfonyl)-3,3-dichlorocamphoryloxaziridine, [(8,8-dimethoxycamphor)sulfonyl]oxaziridine and ethylene ketal of the respective 8-oxocamphor derivative. Much progress was also observed in oxidations with the Ti(IV)-supported chiral reagents. The Kagan and Modena methods were further elaborated. The highest e.es were observed using Ti(Oi-Pr)4/DET/H2O in 1:2:1 ratio [33] or Ti(Oi-Pr)4/DET/i-PrOH (1:4:4) + molecular sieves, both with cumyl hydroperoxide. The non-linear enantioselectivity effects (NLE) were found for these systems as a proof for involvement of the chiral dimeric Ti-species. Uemura made an important modification to this oxidant by replacement of diethyl tartrate with Binol. Also chiral 1,2-diols and C3-symmetric triols were used as chiral inducers with the Ti- supported system. The other approach exploited chiral hydroperoxide obtained via biooxidation of hydrocarbon. Thus prepared oxidant gave enantioselective sulfoxidation with ca. 80 % e.e. In the field of catalytic sulfoxidations an important advancement was made by Bolm and Binewald who discovered the system active even at the 0.01 % mol level of chiral inducer. The catalyst was in situ formed from vanadyl acetylacetonate and (S)-(-)-N-(3,5-di-tert-butylsalicylidene)tert-leucinol and 30% aqueous hydrogen peroxide was applied as a stoichiometric oxidant. The results attained were within 70-80 % e.e. level for simple alkyl aryl sulfoxides, [57] and over 91 % e.e. for the oxidation of di(tert-butyl) disulfide [59]. The catalytic system was further optimized and 75-95 % e.es were observed for the oxidation of thioanisole, 2-aryl-1,3-dithianes and 1,2-bis(arylthio)ethanes [61]. The other successful catalytic oxidant was the Uemura system (Ti(Oi-Pr)4/Binol/H2O, 5 % mol of Binol). In this version the system gave truly enantioselective oxygen transfer (98 % e.e.). Many papers have been published on the application of the biological oxidants and the use of such methods is a feasible alternative to the chemical ones. In particular, the microbiological systems containing fungi Helmithosporium were successfully applied for the preparative oxidation of prochiral thioketals and thioacetals, which could not be oxidized by purely chemical means. Also various bacterial strains of Pseudomonas sp. were used and, e.g. hexyl methyl and cyclohexyl methyl sulfides were oxidized to the respective sulfoxides with high enantioselectivity. Bacterial cyclohexanone monooxygenase was studied most widely among all the purified enzymes used in sulfoxidations. Asymmetric sulfoxidation was also investigated with hydrogen peroxide and vanadium bromoperoxidase and high enantioselectivities were obtained particularly for cyclic sulfides and those having a carboxylic group.