Title of Invention

PROCESS FOR DESULPHURISING HYDROCARBONS CONTAINING THIOPHENE DERIVATIVES

Abstract

This invention discloses selective desulphurisation process of thiophenic derivatives contained in the hydrocarbons derived from the distillation of crude oil, refined or otherwise, comprising of oxidising the thiophenic sulphur atoms into sulphones in presence of an oxidant and to separate the sulphur-containing compounds from the said hydrocarbons, the process being characterised in that it comprises of at least a first stage of oxidation/adsorption by heterogeneous catalysis of sulphur compounds, in organic medium, at a temperature of at least 40°C, in presence of an organic oxidant from the family of peroxides and paracids and in presence of a catalyst of specific surface area greater than 100m2/g and of porosity ranging from 0.2 to 4 ml/g, and a second stage of regeneration of used catalyst, the regeneration stage always following the oxidation/adsorption stage.

Full Text

PROCESS FOR DESULPHURISING HYDROCARBONS CONTAINING THIOPHENIC DERIVATIVES (Amended Page 1) The present indention concerns a process for desulphurisation of hydrocarbons, in particular the desulphurisation of hydrocarbon based gas oil fuel, kerosenes and petrols. It deals especially with the desulphurisation of hydrocarbon based motor fuels containing dibenzothiophenic compounds. The presence of sulphur in these fuels is considered a major environmental problem today. Actually, during combustion, sulphur is converted into various oxides of sulphur, which transform into acids, thus contributing to acid rain formation. The refineries generally use catalytic HDS processes to reduce the sulphur content of fuels. Thus the gas oils derived directly from distillation are hydrotreated between 300 and 400°c, under a hydrogen pressure ranging betweer 30 and 100 bars (30 to 100.105Pa) in the presence of a catalyst placed on a fixed bed and consisting of metal sulphides of groups VIb and VIII, fox- example cobalt molybdenum sulphides or nickel molybdenum sulphides, deposited or alumina. In view of the operating conditions and the hydrogen consumption, these processes may prove to be costly both in terms of investment and operation, especially if the fuel to be produced should have very low sulphur content. Thus for desulphurisation, a fuel containing initially 1 % by weight of sulphur, for reducing sulphur content to 0.05-0.005 % oy weight, the size of the reactor may have to be increased 4 times and the quantity of hydrogen necessary for reaction may have to be increased around 20 times. It is specially difficult to eliminate sulphur traces by means of such processes, more so if sulphur belongs to the sterically hindered alkylated dibenzothiophene molecules in position 4, or 4 and 6.' In certain countries like Sweden and U.S.A, particularly in California, and other countries, the total sulphur content of gas oils is already limited to 0.005 % by weight. This limitation could be .... applicable within a certain time frame in the OEDC countries. For Europe, this objective of 0.005 % by weight of total sulphur content should be achieved by 2005. In contrast to gas oils, petrol is not derived not only by the direct distillation of crude oil, in which the sulphur content is low, but also from several processes such as reforming of naphtha, isomerising of light naphtha, alkylation of butane or propane to isooctane, methoxylation of isobutene and the catalytic cracking of distillates under vacuum or in residual atmosphere. In particular, the catalytic cracking produces about 20 to 60 % by weight cf final petrol. Besides, these contain up to 0.1 % by weight of sulphur. It is, therefore, customary to desulphurise petrol derived from catalytic cracking by processes similar to those described for hydro- desulphurisation of gas oils, for which the operating conditions are more severe with respect to hydrogen pressure, space velocity and temperature. Even though these processes are costly, sulphur content between 0.005-0.03 % by weight cannot be obtained from cracked petrol by such a traditional method. For the purpose of reducing the sulphur content, refiners thought of adding additives, particularly mercaptans and sulphides to the cracking catalyst, to decompose the sulphur compounds which are formed during the process; such additives, however, have little or no effect on benzothiophenic derivatives, even if the mercaptans and sulphides have been eliminated before cracking. In the case of petrol from catalytic cracking which produces sulphur in the petrol, hydrodesulphurisation is not only ineffective on thiophenic compounds, but also destructive with respect of the octane number of petrol. In fact, during the hydrodesulphurisation reaction, there occurs a partial hydrogenation of olefins contained in this cracked petrol, their elimination causes the octane number of petrol to drop, thereby resulting in Deterioration of petrol quality. To compensate for this loss, it is possible to introduce other constituents to improve this number or reprocess the petrol itself so as to increase this number. Including additives or reprocessing so as to improve the petrol quality will increase the cost price, it is, therefore, advantageous to have a process which will help eliminate compounds like benzothiophenic derivatives directly, while reducing the use of hydrogen. Processes for selective oxidation of sulphur compounds are among the treating processes intended for this purpose. Among the methods and processes developed for reducing the quantity of sulphur present in the fuels in the form of thiophenic derivatives, oxidation by organic peroxides, organic hydroperoxides, hydrogen peroxides and organic peracids, was envisaged either without catalyst or by homogeneous catalysing in the presence of catalysts having a base of organometallic or metallic oxide compounds in aqueous phase (see US 3 668 117, US 3 565 793, EP 0565 324 and the publications of T.A KOCH, K.R KRAUSE, L.EMANZER,H. MEHDIZADEH, J.M ODOM, S.K SENGUPTA, New J. Chem. , 1996, 20, 163-173, and F.M COLLINS, A.R LUCY, C.SHARP, C.SHARP, J. of Molecular Catalysis: Chemical 117 (1997) 397-403. In case of processes deploying metallic catalysts with molybdenum and tungsten bases in the presence of hydrogen peroxide in aqueous solution (heterogeneous catalysis), we have to operate at temperatures greater than 60°c and there is an excessive consumption of hydrogen peroxide, a portion of this oxidant being decomposed by the catalyst used. The peracids used, being very powerful oxidants obtained by reaction of hydrogen peroxide with a carboxylic acid such as formic acid or acetic acid, are generally less efficient than hydrogen peroxide and less selective towards sulphur compounds and might oxidise olefins in particular. Other oxydesulphurisation processes in the organic medium have been proposed. These consist in bringing into contact metallic oxides or metallic compounds containing peroxo groups in aqueous or organic solutions, with hydrocarbons containing these sterically hindered sulphur compounds, in the presence or absence of organic or aqueous peroxides, these being introduced with a solvent of alcohol type or in water (see US 3 816 301, US 4 956 578, US 5 958 224). Another process, described in the US patent 3 945 914, consists in producing a desulphurised hydrocarbon material in three stages of treatment. The first step consists of oxidising, at least partially, the sulphur compounds by establishing contact with peroxides, in the presence of metallic catalysts containing the metals of the group comprising titanium, zirconium, molybdenum, tungsten, vanadium, tantalum, chromium and their mixtures, in liquid or solid form, supported if necessary, the supports not being essential for reaction. The second stage consists of bringing in contact the hydrocarbon material containing these oxide compounds with another metallic compound, metallic oxide or peroxide (metals belonging to the group comprising nickel, molybdenum, cobalt, tungsten, iron, zinc, vanadium, copper, manganese, mercury and their mixtures), at a temperature ranging from 250° to 730°C, under hydrogen pressure. The third stage consists of recovering the desulphurised hydrocarbon containing material. In all these methods and processes, the derivatives of thiophene are transformed to their sulphonated and/or sulphonic form. However, for some of these compounds, even at high temperature, the reaction is relatively slow and it takes at least one hour to achieve total conversion; else very high concentration of an oxidant is required, often in quantities much greater than the quantities necessary for the oxidation of sulphur derivatives. In other cases, it is possible to work in multiple stages, but they are expensive in terms of time and programmed monitoring. The present invention therefore seeks to propose a process of desulphurisation of hydrocarbons, particularly those used as fuel bases containing thiophenic derivatives, without reducing the octane number or the cetane number, sometimes even increasing these numbers. This deals particularly with the finishing treatment of hydrotreated gas oils, kerosene and catalytic cracked petrol, with high concentration of sterically hindered thiophenic derivatives, by hydrogenation. This invention also proposes such a process that helps achieve equal or even higher levels of oxidation than that through known processes, while reducing the reaction time and the separation of sulphur oxide compounds from desulphurised hydrocarbons. The purpose of the present invention is, therefore, to have a selective desulphurisation process of thiophenic compounds contained in the hydrocarbons derived from the distillation of crude oil, refined or otherwise, to oxidise the thiophenic sulphur atoms into sulphones in the presence of an oxidant and a catalyst, and to separate the sulphonated compounds obtained from the said hydrocarbons; this process is characterised by the fact that it consists of at least one first stage of oxidation/adsorption by heterogeneous catalysis of sulphur compounds, in organic medium, at a temperature of at least 40°C, in the presence of an organic oxidant from the family of peroxides and peracids and in presence of a catalyst of specific surface area greater than 100 m2/g and of porosity ranging from 0.2 to 4 ml/g, and a second stage of regeneration always after the stage of oxidation/adsorption. For the purposes of this invention, thiophenic derivatives implies, benzothiophenic compounds, poly benzothiophenic compounds and their alkyl derivatives, among which alkyldibenzothiopnenes, especially ones which are sterically hindered by conversion processes usually used by the refiners. The process covered by this invention has the advantage of not only ensuring, at atmospheric pressure, oxidation of the entire sulphur contained in the hydrocarbons and more selectively a conversion of thiophenic derivatives into sulphones, by means of a simple industrial process, but also of adsorbing simultaneously these sulphoxides on the catalyst. In fact the separation of hydrocarbons from the major part of the sulphones and formed sulphoxides is immediate; the latter get deposited in solid form on the catalyst or in the form of deposits which can be filtered by any known means, in the treated hydrocarbons. This catalyst, on which these sulphoxides have been absorbed, constitutes the 'used catalyst'. In the event of the sulphones being dissolved in the treated hydrocarbons, they can be extracted. However, this oxidation/adsorption has no effect on the olefins, so it does not modify, in the catalytic cracked petrol, the octane number or the proportion of non-sulphurised aromatic compounds. Besides, the oxidation process of this invention improves the cetane number of gas oils. Without any theoretical limitations, it is apparent that greater the specific surface area of the catalyst, the longer is it active. Furthermore, compounds of sulphone and sulphoxide type have a strongly polar character, so they are maintained on the catalyst surface, probably at the level of Lewis acids sites of the catalyst. Similarly, larger the size of the pores, lesser is the risk of the pores of the catalyst getting blocked rapidly, and, longer the guaranteed life of the catalyst during the oxidation cycle. For the present invention, it is a quest ion of selecting the catalyst which offers the best compromise between specific surface area and pore size so as to obtain an activity that is sufficient and lasts as long as possible to have the most effective oxidation/adsorption. When the process is put to continued operation in an intermittent manner, the stages of oxidation/ adsorption and regeneration may be carried out in the same reactor or simultaneously in reactors positioned parallel and functioning alternatively with one or other of the stages in a fixed bed, or at least two reactors with mobile beds connected to each other by the catalytic bed, one of them being dedicated to oxidation/adsorption, the other to regeneration. In fixed bed, the first reactor containing a fixed bed of catalyst receives the hydrocarbon and oxidant fluxes, and the second receives, for regeneration of the catalyst, liquid effluents, for example a washing solvent or oxidising gaseous effluents, such as air or a mixture of air/N2, the temperature of the catalytic bed being recorded. These reactors exchange their functions when the efficiency of catalyst in the oxidation/adsorption reactor is no longer sufficient for oxidation and/or adsorption. In the mobile bed, ;he hydrocarbons are fed in the first reactor where oxidatior takes place, the catalyst being progressively pushed towards the second reactor, where it is regenerated before being sent back to the oxidation/adsorption reactor. Mobile bed reactors, which are well known in the reforming field, may be used in this device. A third reactor is used in this operating mode, which is placed between the first two reactors and helps eliminate the used hydrocarbons from the catalyst before washing the same, or to carry out the combustion of the sulphone compounds and the trapped sulphoxides. The catalysts used in this invention are selected from among the supports of the group comprising of silica, alumina, zirconia, amorphous or crystalline aluminosilicates, aluminophosphates, mesoporous silica solids and silicoaluminates, active carbons and clay, these supports being used either alone or in mixture. In the catalysts of this invention, these supports may be used advantageously as supports of the metal group comprising of titanium, zirconium, vanadium, chromium, molybdenum, iron, manganese, cerium and tungsten, these metals may be introduced in the oxide form, in the support network or deposited on the support surface. In fact, a synergic effect has been observed between the metal and the support, that means, an unanticipated increase in the catalyst activity with regard to the oxidation of thiophenic compounds and, at the same time, an increase in the trapping of sulphone and sulphoxide compounds in the pores of the catalyst, without any of them being ultimately desorbed. In the inventive process, the catalyst contains about 0 to 30% by weight of metal in the form of oxide on at least one support. Preferably the catalyst contains 0 to 20% of metal in the form of oxide. Among the supports consisting of sterically hindered oxides, the gamma alumina, silica, mesoporous silica solids and silicoalumina , are preferred. Among the supported catalysts, those containing tungsten or titanium in the form of oxide deposited on a support or introduced in the network, this support being selected from silica, alumina and the aluminosilicates, alone or in mixture. In a preferred mode of operation of the process, the molar ratio of oxidart/total sulphur contained in the hydrocarbons is between 2 and 20, preferably between 2 and 6. As per the invention, the oxidants are selected from among the compounds of general formula R1OOR2, in which R1 and R2 are the same or different, selected from among hydrogen, linear or branched alkali groups, containing from 1 to 30 atoms of carbon and the aryl or alkylaryl groups whose aryl pattern is, if necessary, substituted by alkylaryl groups, as R1 and R2 cannot simultaneously be hydrogen. (Amended Page 8) In a preferred mode, the oxidant of formula R1OOR2 is selected from the group comprising of tert-butyl hydroperoxide and ditert-butylperoxide. Other oxidants of this invention, the peracids of formula R3COOOH, are selected in such a manner that R3 is hydrogen or a linear or branched alkyl group comprising 1 to 30 atoms of carbon. They are selected preferably from the group comprising of peracetic acid, performic acid and perbenzoic acid. In the inventive process, the stage of regeneration of catalyst consists of removing the formed deposits by washing or by combustion. For washing, we preferably use a polar solvent, from group comprising of waiter, linear or branched alkanols containing from 1 to 30 carbon atoms, singly or mixed with water, alkylnitriles, comprising 1 to 6 atoms of carbon; the preferred ones are water, acetonitrile, methanol and their mixtures. By combustion, the catalyst is brought to a maximum temperature of 800°C, preferably a temperature a pressure ranging between 105Pa to 106Pa, preferably from 105Pa to 2.105Pa, in the presence of an oxidant gas. By oxidant gas is meant, pure oxygen and all gaseous mixtures containing oxygen, particularly mixtures of oxygen and nitrogen and air itself. The quantity of oxygen in nitrogen is adjusted in such a manner as to limit the formation of water vapour, as a considerable quantity of water vapour will have a secondary effect of modifying the structure of the catalyst pores with a decrease in their volume!, particularly when it contains the crystalline aluminosilicates such as zeolites or aluminophosphates, as support. This adjustment also enables to control changes in temperature related to the exothermal property of combustion. Another objective of this invention is a device for operating the process defined above; the device consists of at least one first reactor containing an oxidation catalyst and having lines for entry o:: hydrocarbons and oxidant and a line for exit of desulphurised hydrocarbons, and if need be, a second reactor comprising inlet lines for solvent or the oxidant gas of catalyst, with a view to regenerating the same, and a line for exit of .... (Amended Page 9) combustion gas By oxidant' gas,, it is meant here, mixtures of oxygen/air, air/nitrogen and oxygen/nitrogen. When the device comprises of two reactors, the reactors may function ir fixed bed or mobile bed. Another objective of the invention is the application of the process defined above to the specific finishing treatment of petrol produced from catalytic cracking or even to the treatment of gas oils having been previously hydrotreated and of kerosene, for obtaining better economy with the process. This invention will be described in greater detail by means of reference to diagrams given in the annexure. These are: - Figure 1 is a diagram of a device with two reactors functioning alternatively, during oxidation and during regeneration of catalyst. Figure 2 is the diagram of a device comprising two reactors with a mobile bed, the first corresponding to the oxidation stage, and the second to the regeneration of catalyst, a line for return of regenerated catalyst being added to the system. Figures 3-1 and 3-2 represent curves illustrating the total sulphur content as a function of time, and hydrocarbons treated as per inventior in the following example III. The device in figure 1 comprises two reactors 1 and 2 loaded with a catalyst placed in fixed bed. When reactor 1 functions in oxidation and reactor 2 during regeneration , the line 3 brings, to the reactor 1, the charge of sulphur- containing hydrocatbons, in which the oxidant has been introduced via line 4, the three-way valve 6a and the line 8a. The desulphurised hydrocarbon flux exits reactor 1 by means of line 9a and rejoins line 10a for evacuation of desulphurised hydrocarbons via the thiee-way valve 7a. In the same way, line 5 supplies to reactor 2 either an appropriate solvent, of an oxidant gas, via th-e - three-way valve 6b and the line 8b. When the reactor operates during combustion, the temperature of the catalytic bed is maintained at 500°C. The solvent containing sulphones recovered from the catalyst or the combustion gases, SO2, CO and CO2 mainly, are evacuated via. . . . lines 9b, the three-way valve 7b and the line 11b in the line 11a. When the regeneration of the catalyst is completed and the catalyst activity of reactor 1 becomes insufficient, the functioning of the two reactors is interchanged. Thus, the hydrocarbon/oxidant mixture uses the line 3a and the valve 6b, to enter the reactor 2 The desulphurised hydrocarbons are evacuated by the line 9a and are directed towards the blowing line 10a via the valve 7b and the line 10b. Similarly, the solvent or the oxidant gas arriving by line 5, is directed to the reactor 1 via line 3a, the valve 6a and the line 8a. The solvent or oxidant gas is brought into the drain line 11a via line 9a and the valve 7a. The valves 6a, 6b, 7a and 7b may be changed by a common process to enable circulation of the proposed fluxes. It is advantageous to place a filter, on one of the lines 9a or 9b, or even 10a or 10b, for collecting the solid sulphones formed during oxidation, which remained suspended in the hydrocarbons. It is also advantageous to add traps for sulphur containing absorbents of silica or activated alumina type, on the same lines, downstream of these filters, so as to trap the sulphones still dissolved in the treated hydrocarbons. The device in figure 2 comprises two reactors 20a and 20b placed in series, each containing a mobile bed of catalyst, the reactor 20a functioning in regenerative mode, and propulsion device 30 enabling return of catalyst from reactor 20b to reactor 20a. The hydrocarbons are fed by the line 40 to the reactor 20a, after being mixed with the oxidant via line 50. For example the reactor 20a. may be selected from among the reactors with funnels, the mobile bed of the catalyst moving by gravity towards the lower portion of the reactor. Thus while the desulphurised hydrocarbons are evacuated by the line 60, the catalyst is pushed by gravity into the reactor 20b by the line 70. The solvent or combustion gas is introduced via channel 80 into the reactor 20b. In order to carry out regeneration by combustion, the temperature is increased and maintained at 500°C. The solvent charged with sulphones or combustion gas is evacuated by the line 100. As these mobile beds generally function in an intermittent manner, the catalyst not being continuously displaced, it is advantageous to provide a purge of solvent or nitrogen on the reactor for removal of hydrocarbons before washing, and/or for removal of combustion gas by stripping with nitrogen. At the outlet of reactor 20 b, the regenerated catalyst is taken via line 110, t) the device 30. This device may be a device for propulsion by gas under pressure or a lifting screw. It brings the regenerated catalyst back to the reactor 20a, via line 120. . In certain modes of specific operation of these mobile reactors, reactors 20a and 20b may form part of the same unit with two separate stages. The following examples illustrate the effectiveness of the invention process, without being limited to these. EXAMPLE 1 This example seeks to describe the effectiveness of the process as per this invention, with regard to the removal of derivatives of dibenzothiophene present in the bases for partially desulphurised fuels. The samples of catalysts used are of two types, catalysts formed with a single support, and those to which one or more metals have been impregnated. The following table 1 gives the specific surface area characteristics and the porosity of each of them. The catalysts C2, C3 and C6 have been obtained by impregnation of a wet metallic salt, ammonium metatungstate and ammonium hexamolybdate, at a proportion of 140 mg per gram of support, then dried and finally calcined at a temperature of 500°C. The catalyst C4 has been obtained by treating a beta zeolite with commercial titanium as per procedure described in the patent EP 0 842 114. For testing the activity of these catalysts during oxidation and as a function of time, 20 ml of catalyst is introduced in a micropilot of 150 ml. On the catalyst is circulated a charge of middle distillates after hydrotreatment, boosted with 1800 ppm of tert-butyl hydroperoxide (tBHP) , ar. hourly space velocity (VVH) of 1h-1 under atmospheric pressure, at a temperature of 70°C. Samples are taken regularly during oxidation in order to measure the catalyst activity in time. A comparative sample, called Tl, corresponding to the use of the catalyst only without peroxide, is also monitored. At the end of two hours of operation, these results confirm that, except for the effect due to the nature of the catalyst, the more we increase the pore size of the catalyst and the specific surface area, more the sulphur content of treated hydrocarbons reduces. It is also observed that the catalyst activity increases when it consists of a metallic oxide with support. In contrast at the end of 24 hours, whatever be the catalyst, we observe a slight increase in the sulphur content of desulphurised hydrocarbons, which corresponds to the beginning of blocking of the catalyst pores, the sulphones and sulphoxides attached to it. By this process it is clear that the selection of a catalyst for the inventive process is the result of a compromise between the nature of the catalyst, its specific surface area and the size of its pores. EXAMPLE II In this example the efficiency of the catalyst, as a function of oxidation of its constituents, is measured. We proceed as in Example 1, with catalysts C1 - C6 and study the formation of sulphones and sulphoxides with respect to the dibenzothiophene compounds, notably benzothiophene (BT), dibenzothiophene(EBT) and 4,6 dimethylbenzothiophene (DMBT), by gas chromazography equipped with a specific detector of sulphur (SIEVERS method). The results obtained are collated in the following table. These results show that there is at least 80 % conversion of the sterically hindered thiophenic derivatives, with catalysts constituted of a single support, and more than 90 % with catalysts constituted of supports and at least one metal in the form of metallic oxide inserted in the network of support or deposited on the support. Example III The purpose of this example is to show, analogous to oxidation, the effect, as a function of time, of adsorption of sulphone compounds on the oxidation/adsorption sequence and regeneration, and the efficiency of the regeneration operation with respect to oxidation/adsorption. We proceed with the catalyst C3 under the operating conditions described in Example 1 for a middle distillate containing 44 ppm of sulphur after hydrotreatment, and in the presence of 600 ppm of tEHP. The results of oxidation/adsorption are given in Figure 3-1, when the catalyst is fresh. After two days, the total sulphur content in the hydrocarbons increases significantly to the initial value, in the absence of treatment as per the invention. The results of Figure 3-2 correspond to the monitoring of sulphur content of the same hydrocarbons when the same catalyst C3 regenerated by combustion, was used. The results obtained on a fresh catalyst are almost identical to those obtained on the same regenerated, catalyst. These two curves show the significance of the process of this invention, which propose an alternative functioning of the same catalyst during oxidation/adsorption, the oxidation/adsorption time actually been adapted to the proportion of sulphur. CLAIMS 1- Selective desuphurisation process of thiophenic derivatives contained in the hydrocarbons derived from the distillation of crude oil, refined or otherwise, comprising of oxidising the thiophenic sulphur atoms into sulphones in presence of an oxidant and to separate the sulphur-containing compounds from the said hydrocarbons, the process being characterised in that it comprises of at least a first stage of oxidation/ adsorption by heterogeneous catalysis of sulphur compounds, in organic medium, at a temperature of at least 40°C, in presence of an organic oxidant from the family of peroxides and peracids and in presence of a catalyst of specific surface area greater than 100m2/g and of porosity ranging from 0.2 to 4 ml/g, and a second stage of regeneration of used catalyst, the regeneration stage always following the oxidation/adsorption stage. 2- Process as claimed in claim 1, characterised in that stages of oxidation/adsorption and of regeneration are carried out successively in the same reactor on the same catalvst. 3- Process as claimed in claim 1, characterised in that stages of oxidation/adsorption and regeneration are carried out simultaneously in the reactors (1,2) placed in parallel and alternating with one or other stage. 4- Process as claimed in claim 1, characterised in that stages of oxidation/adsorption and regeneration are carried out in the two reactors with mobile beds (20a, 20b) connected to each other by the catalytic bed, one of them dedicated to oxidation, the other to regeneration. 5- Process as claimed in any one of the claims 1 to 5, characterised in that the oxidant is selected from the group comprising of organic peroxides, organic hydroperoxides and peracids. 6- Process as claimed in claims 1 and 2 characterised in that the catalyst comprises a support is selected from the group comprising of sil:.ca, alumina, zirconia, amorphous or crystalline aluminosilicates, aluminophosphates, mesoporous solids, active carbons, clay and their mixtures. 7- Process as claimed in claim 6, characterised in that the catalyst contains ab least a metal selected from the group comprising of titanium, zirconium, vanadium, chromium, molybdenum, iron, (Amended page 16) manganese and tungsten, this metal being introduced in the support network or deposited in the form of oxide on the support. 8- Process as claimed in any one of the claims 1 to 7, characterised in that the catalyst containing 0 to 30 % by weight, preferably, from 0 to 20 % by weight of metal in the form of oxide. 9- Process as claimed in any one of the claims 1 to 8, characterised in that the catalyst consists of at least one support selected from gamma alumina, silica and mesoporous silica solids and silicoaluminos. 10- Process as claimed in any one of the claims 1 to 9, characterised in that the supported catalyst is selected from catalysts containing tungsten on a support selected from silica and alumina, singly or in a mixture. 11- Process as claimed in any one of the claims 1 to 10, characterised in that the molar ratio of oxidant/total sulphur in the hydrocarbons ranges from 2-20, preferably from 2-6. 12- Process as claimed in any one of the claims 1 to 11, characterised in that the oxidant is a compound of general formula R1OOR2, in which R and R2 can be the same or different in the group comprising of the hydrogen atom and groups of alkyl, linear or branched , containing 1 to 30 atoms of carbon, as R and R2 cannot simultaneously be hydrogen. 13- Process as claimd in claim 12, characterised in that the oxidant being selected from the group comprising of tert- butyl hydroperoxide and iitert-butyl peroxide. 14- Process as claimed in any one of the claims 1 to 13, characterised in that the oxidant is a peracid of formula R3COOOH, in which R3 is h/drogen or a linear or branched alkyl group containing 1 to 30 carbon atoms. 15- Process as claimed in claim 14, characterised in that the oxidant is selected from the group comprising of peracetic acid, performic acid and perbenzoic acid. 16- Process as claimed in any one of the claims 1 to 15, characterised in that the catalyst regeneration stage consists of removing the deposits formed by washing or combustion. This invention discloses selective desulphurisation process of thiophenic derivatives contained in the hydrocarbons derived from the distillation of crude oil, refined or otherwise, comprising of oxidising the thiophenic sulphur atoms into sulphones in presence of an oxidant and to separate the sulphur-containing compounds from the said hydrocarbons, the process being characterised in that it comprises of at least a first stage of oxidation/adsorption by heterogeneous catalysis of sulphur compounds, in organic medium, at a temperature of at least 40°C, in presence of an organic oxidant from the family of peroxides and paracids and in presence of a catalyst of specific surface area greater than 100m2/g and of porosity ranging from 0.2 to 4 ml/g, and a second stage of regeneration of used catalyst, the regeneration stage always following the oxidation/adsorption stage.

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841-kolnp-2003-granted-abstract.pdf

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