Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G27/00—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation
  • C10G27/04—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen
  • C10G27/12—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen with oxygen-generating compounds, e.g. per-compounds, chromic acid, chromates

Definitions

• ABSTRACT A process for reducing the sulfur content of sulfurcontaining hydrocarbon material by oxidizing at least a portion of the sulfur in the sulfur-containing hydrocarbon material with an oxidant in the presence of certain catalysts, for example, a molybdenumcontaining catalyst.
• the oxidized sulfur-containing hydrocarbon material is further processed by means of a sulfur reducing step to remove sulfur from the hydrocarbon material.
• a hydrocarbon material having reduced sulfur content is thereafter recovered.
• the preferred oxidant is tertiary butyl hydroperoxide and the oxidation may occur in the presence of a solvent, preferably tertiary butyl alcohol.
• the tertiary butyl alcohol which is removed from the oxidized sulfurcontaining hydrocarbon material, can be dehydrated to isobutylene and further dimerized to form diisobutylene.
• the present invention relates to an improved process for catalytically reducing the sulfur content of hydrocarbon materials. More particularly, the invention relates to the reduction in sulfur content of hydrocarbon materials by the catalytic oxidation of the sulfur impurities contained therein, followed by removal of these oxidized impurities.
• Petroleum crude oils and topped or reduced crude oils, as well as other heavy petroleum fractions and/or distillates including vacuum tower bottoms, atmospheric tower botttoms, black oils, heavy cycle stocks, visbreaker product effluent and the like, are normally contaminated by excessive concentrations of sulfur.
• This sulfur may be present in heteroatomic compound which have proven difficult to remove by conventional processing.
• the sulfur compounds are objectionable, for example, because combustion of fuels containing these impurities results in the release of sulfur oxides which are noxious, corrosive and, therefore, present a serious problem with respect to pollution of the atmosphere.
• U.S. Pat. No. 3,565,793 relates to a method for desulfurization of hydrocarbon materials by oxidizing the sulfur-containing hydrocarbon with an oxidant in the presence of a catalyst, followed by a sulfur reducing step.
• the sulfur-containing hydrocarbon material is a complex mixture of components and includes sulfur in the form of hetero-atomic sulfur compounds, e.g., thiophene sulfur compounds, which are known to be difficult to remove.
• a still further problem having to do with process efficiency is the problem of developing a plentiful and inexpensive source of oxidant effective to preferentially oxidize the sulfur in hydrocarbon materials. Closely linked with this problem is the additional concern of finding uses for the oxidant decomposition products which result from sulfur oxidation. Therefore, it would be advantageous to provide an efficient desulfurization process whereby a plentiful supply of effective oxidant is produced, the oxidant is utilized to preferentially oxidize the sulfur in hydrocarbon material and to provide useful oxidant decomposition product or products.
• Another object of the present invention is to provide an improved process for the desulfurization of sulfurcontaining hydrocarbon materials.
• An additional object of the present invention is to provide an efficient process for producing hydrocarbon material having reduced sulfur content utilizing the cat alytic oxidation of sulfur impurities contained in hydrocarbon material.
• a base treatment step for example, a base treatment step, a thermal treatment step, a solvent refining step, a hydro-desulfurization step and the like, to remove sulfur from the hydrocarbon material.
• a hydrocarbon material having reduced sulfur content is thereafter recovered.
• metallic molybdenum is interacted, i.e., co-mingled or contacted, with at least one peroxy compound, e.g., organic hydroperoxide, organic peroxide, organic peracid, hydrogen peroxide and mixtures thereof, in the presence of at least one low molecular weight saturated alcohol, either monoor poly-hydroxy, containing from one to four carbon atoms per molecule to solubilize at least a portion of the molybdenum metal. It is believed that the molybdenum metal reacts with the peroxy compound to form a compound or complex which is soluble in the saturated alcohol and remaining peroxy compound.
• at least one peroxy compound e.g., organic hydroperoxide, organic peroxide, organic peracid, hydrogen peroxide and mixtures thereof.
• at least one low molecular weight saturated alcohol either monoor poly-hydroxy, containing from one to four carbon atoms per molecule to solubilize at least a portion of the molybdenum metal. It is believed that the moly
• Typical peroxides, hydroperoxides and peracids useful in the preparation of the molybdenum-containing catalyst are described hereinafter as oxidants. These peroxy compounds may also be substituted with groups such as halides, --NI-l -SH,
• the most preferred peroxy compound for use in preparing this molbdenumcontaining catalyst is tertiary butyl hydroperoxide.
• Hydrogen peroxide suitable for preparing the molybdenum-containing catalyst is preferably used in the form of an aqueous solution containing, for example, from about to about 60%, preferably about 30 percent, by weight of hydrogen peroxide.
• low molecular weight monohydroxy alcohols which are suitable for use in the preparation of the present molybdenum-containing catalyst include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, tertiary butyl alcohol and the like.
• the low molecular weight polyhydroxy alcohols which are suitable include ethylene glycol, propylene glycol, 1,2-butylene glycol and glycerol. In general, either monoor poly-hydroxy alcohols containing from one to four carbon atoms per molecule are suitable.
• the molybdenum metal be interacted with tertiary butyl hydroperoxide in the presence of tertiary butyl alcohol.
• tertiary butyl alcohol is used as the saturated alcohol, it is preferred, to enhance molybdenum solubility, that the interaction mixture comprise at least one monoor poly-hydroxy alcohol having from one to about 16 carbon atoms per molecule, at least one primary hydroxy group, and be present in an amount of from about 1 to about 25 percent by weight of the total alcohol present.
• a particularly preferred alcohol mixture for use in combination with tertiary butyl alcohol isthe stream of higher poly-hydroxy alcohols having a molecular weight in the rangefrom about 200 to about 300 and containing from about 4 to about 6 hydroxy groups derived from propylene epoxidation and described in US. Pat. No. 3,573,226.
• the relative proportions of peroxy compound and low molecular weight saturated alcohol employed in preparing the catalyst may vary over a broad range and is, therefore, not of critical importance to the invention.
• the peroxy compound comprises from about 5 to about 50 percent by weight of the total peroxy compound and saturated low molecular weight alcohol used in catalyst preparation.
• the molybdenum concentration in the catalyst mixture i.e., the mixture comprising the dissolved or soluble molybdenum plus any excess peroxy compound and alcohol, often is within the range from about ppm. to about 5 percent, preferably in the range from about 1,000 ppm. to about 2 percent by weight of the total mixture. It may be desirable to prepare the catalyst in the presence of a solvent such as benzene, ethyl acetate and the like, in order to obtain the optimum molybdenum concentration in the final catalyst mixture. However, if this type of dilution is desired, it is preferred that an excess of tertiary butyl alcohol be maintained in the catalyst mixture for this purpose.
• the molybdenum metal useful in the preparation of the present catalyst may be in the form of lumps, sheets, foil or powder.
• the powdered material e.g., having a particle size such that it passes through a 50 mesh sieve, preferably through a 200 mesh sieve, on
• the molybdenum metal-peroxy compound interacting may be carried out at a wide range of temperatures, for example, temperatures within the range from about 25C. to about 150C. Interacting pressures should be set to avoid extensive vaporization of the peroxy compound and alcohol. Typical interacting pressures may range from about 1 psia. to about psia. In many instances, atmospheric pressure may be used.
• the product from the interacting may be filtered to separate the undissolved molybdenum from the catalyst mixture which is thereafter suitable for use as a catalyst for the oxidation of sulfur impurities in hydrocarbon materials.
• ganic hydroperoxides organic peracids, and mixtures thereof.
• These oxidants have been found to give excellent desulfurization when combined with the reducing and recovery steps described herein.
• the use of these oxidants have been found to be selective or preferential for oxidation of the sulfur, that is, substantial amounts of carbon oxidation products such as acids and ketones are not formed.
• high product yields in the oxidation step both as to the high product yield of oxidized sulfur impurities and the high product yield of hydrocarbon materials which remains after the oxidation step and, in particular, after the sulfur reducing step, are obtained utilizing the abovenoted oxidants.
• the organic oxidants suitable for use in the present invention include, by way of example, hydrocarbon peroxides, hydrocarbon hydroperoxides and hydrocarbon peracids wherein the hydrocarbon radicals in general contain up to about 20 carbon atoms per active oxygen atom. With respect to the hydrocarbon peroxides and the hydrocarbon hydroperoxides, it is particularly preferred that such hydrocarbon radical contain from about four to about 18 carbon atoms per active oxygen atom and more particularly from four to 10 carbon atoms per active oxygen atom.
• the hydrocarbon radical is defined as that radical which is attached to the carbonyl carbon and it is preferred that such hydrocarbon radical contain from one to about 12 carbon atom, more preferably from one to about eight carbon atoms, per active oxygen atom. It is intended that the term organic peracid include, by way of definition, performic acid.
• hydrocarbon radicals are alkyl such as methyl, ethyl, butyl, t-butyl, pentyl, n-octyl and those aliphatic radicals which represent the hydrocarbon portion of a middle distillate of kerosene, and the like; cycloalkyl radicals such as cyclopentyl and the like; alkylated cycloalkyl radicals such as monoand polymethylcyclo-pentyl radicals and the like; aryl radicals such as phenyl, naphthyl and the like; cycloalkyl substituted alkyl radicals such as cyclohexyl methyl and ethyl radicals and the like; alkyl phenyl substituted alkyl radicals examples of which are benzyl, methylbenzyl, caprylbenzyl, phenylethyl, phenylpropyl, naphthylmethyl, naphthylethyl and the like
• oxidants are hydroxyheptyl peroxide, cyclohexanone peroxide, tertiary butyl peracetate, di-tertiary butyl diperphthalate, tertiary butyl perbenzoate methyl ethyl ketone peroxide, dicumyl peroxide, tertiary butyl hydroperoxide, di-ter'tiary butyl peroxide, p-methane hydroperoxide, pinane hydroperoxide, 2,5-dimethylhexane-2,S-dihydroperoxide, cumene hydroperoxide and the like; as well as organic peracids such as performic acid, peracetic acid, trichloroperacetic acid, per-benzoic acid, perphthalic acid and the like.
• the most preferred oxidant for use in the present invention is tertiary butyl hydroperoxide.
• the process of the present invention involves contacting a sulfur-containing hydrocarbon material with an oxidant, for example, of the type described above, in the presence of the above molybdenum-containing catalyst for a time sufficient to effect the oxidation of at least a portion of the sulfur present in the hydrocarbon material.
• an oxidant for example, of the type described above
• the time required for this oxidation to occur is from about 5 minutes to about 24 hours or more. It is preferred that the oxidation occur in a time from about 5 minutes to about 2 hours. Because of the improved oxidation efficiency of the present process, in a more preferred embodiment, the oxidation takes place in a period of time from about 5 minutes to about 25 minutes.
• the catalyst is used in an amount sufficient to promote the preferential oxidation of sulfur in a sulfurcontaining hydrocarbon material. It is preferred that the catalyst be soluble in the liquid portion of the oxidation reaction mass and be present in an amount based on the weight of molybdenum of at least about 5 ppm., more preferably from about ppm. to about 500 ppm., by weight of the sulfur-containing hydrocarbon material.
• the concentration of oxidant can be from about 0.1 to about 10 or more atoms of active, i.e., reducable, oxygen per atom of sulfur present in the hydrocarbon material. However, it is preferred that the oxidant be present in an amount from about I to about 4 atoms of active oxygen per atom of sulfur in the hydrocarbon material. A still more preferred oxidant concentration is from about 1.5 to about 3.0 atoms of active oxygen per atom of sulfur.
• Oxidants useful in the present invention include those having one, two or more atoms of active oxygen per molecule of oxidant.
• the more preferred oxidant concentration range i.e., from about 1.5 to about 3.0 active oxygen atoms per atom of sulfur, is of value if the oxidant decomposition product, for example, an alcohol in the case of hydroperoxide oxidant, is to be stripped from the hydrocarbon material after oxidation and used for different productive purposes.
• the oxidant decomposition product for example, an alcohol in the case of hydroperoxide oxidant
• the decomposition product i.e., tertiary butyl alcohol
• the tertiary butyl alcohol in order to be useful as a gasoline improver, the tertiary butyl alcohol must be essentially free, i.e., less than about 100 ppm., of tertiary butyl hydroperoxide. It has been found that by providing an essentially pure tertiary butyl hydroperoxide oxidant in a concentration from about I.5 moles to about 3.0 moles per mole of sulfur in the hydrocarbon fraction, a product stream of tertiary butyl alcohol, essentially free of excess oxidant can be obtained by stripping the alcohol from the hydrocarbon material after oxidation.
• Oxidant concentrations in excess of about 3.0 moles per mole of sulfur may result in oxidant carry over into the decomposition product stream thereby causing additional processing of this stream to eliminate the oxidant.
• This useful tertiary butyl alcohol product is obtained without sacrificing the substantial oxidation benefits of the invention.
• the oxidation step of the present invention may be carried out over a wide range of temperatures, for example, from about 25F. to about 450F. and preferably from about 50F. to about 300F.
• the oxidation may be carried out at pressures ranging, for example, from about 1 atmosphere to about atmospheres or more.
• oxidant decomposition product or products Before subjecting the hydrocarbon material to the sulfur reduction step, it is preferred to separate out the oxidant decomposition product or products, oxidation solvent, if any, and the alcohol or alcohols from the catalyst mixture.
• This separation can be obtained using conventional techniques, for example, simple distillation and/or stripping the hydrocarbon material during or after oxidation with a gas such as carbon dioxide or nitrogen.
• the oxidized sulfur-containing hydrocarbon material is contacted with a base, preferably an alkali metal hydroxide, for a time sufiicient to reduce the sulfur content of the hydrocarbon material, generally from about 10 minutes to about 24 hours, preferably from about 1 hour to about 6 hours.
• the reaction temperature is generally from about 300F. to about 900F., preferably from about 400F. to about 750F.
• pressures above atmospheric can be utilized in carrying out the base treatment.
• pressures up to I00 atmospheres can be utilized in carrying out the base treatment.
• an alkali metal hydroxide preferably potassium or sodium hydroxide
• the alkaline earth metal hydroxides or oxides, calcined dolomitic materials and alkalized aluminas can be utilized in carrying out the base treatment.
• mixtures of different bases can be utilized.
• an aqueous solution of the base at a concentration on a mole basis of generally from about 1 mole of base to 1 mole of sulfur up to about 4 moles of base per mole of sulfur is utilized.
• sulfur reduction is accomplished by treating the oxidized sulfur at temperatures above 300F., preferably above 500F. and particularly in the temperature range of from about 550F. to
• the thermal decomposition step may be carried out in the presence of suitable promoting materials comprising porous solids having acidic or basic properties for example, ferric oxide on alumina, bausite, thoria on pumice, silica-alumina, soda-lime and acid sodium phosphate on carbon.
• suitable promoting materials comprising porous solids having acidic or basic properties for example, ferric oxide on alumina, bausite, thoria on pumice, silica-alumina, soda-lime and acid sodium phosphate on carbon.
• an inert carrier gas for example, nitrogen, is passed through the reaction mixture to avoid local overheating and also to remove the gaseous sulfur decomposition products.
• the catalytic hydrodesulfurization step may be carried out under relatively mild conditions in a fixed, moving, fluidized or ebullating bed of catalyst.
• a fixed bed of catalyst is used under conditions such that relatively long periods elapse before regeneration becomes necessary, for example, a temperature within the range of from about 500F. to about 900F., preferably from about 650F. to about 800F., and at a pressure within the range of from about 100 psig. to about 3,000 psig. or more.
• a particularly preferred pressure range within which the hydrodesulfurization step provides extremely good sulfur removal while minimizing the amount of pressure and hydrogen required for the hydrodesulfurization step are pressures within the range of about .300 psig. to about 800 psig., more preferably from about 400 psig. to about 600 psig.
• This invention involves the processing of various sulfurcontaining hydrocarbon materials, such as those derived from petroleum sources.
• the sulfur content of these materials may be greater than about 1 percent by weight.
• these hydrocarbon materials contain a significant amount of thiophene sulfur which is known to be difficult to remove.
• hydrocarbon materials which are particularly suited to the present process include heavy hydrocarbon materials such as petroleum fractions containing at least a major amount of material boiling above about 550F., for example, crude oil and atmospheric and vacuum residues which contain about 1 percent by weight or more of sulfur.
• suitable hydrocarbon materials include cracked gas oils, residual fuel oils, topped or reduced crudes, crude petroleum from which the lighter fractions are absent, residues from cracking processes and sulfur-containing hydrocarbon materials from tar sands, oil shale and coal.
• the invention is especially suited to those sulfurcontaining heavy hydrocarbon materials which cannot be deeply flashed without extensive carry over of sulfur-containing compounds.
• Typical examples of the 2,3,4, and S-ring thiophene-containing materials found in heavy hydrocarbon materials which are difficult to remove include benzothiophene, dibenzothiophene, -thia-3,4-benzofluorene, tetraphenylthiophene, diacenaphtho (l,2-b,l 2'-d) thiophene and anthra (2,1,9-cde) thianaphthene.
• the hydrocarbon material may also contain non-thiophene sulfur, various sulfides, and elemental sulfur which can be removed by the process of the present invention.
• the preferred oxidation catalyst for use in the present invention is prepared using a combination of molybdenum metal, tertiary butyl hydroperoxide and tertiary butyl alcohol.
• the preferred oxidant for use is tertiary butyl hydroperoxide.
• tertiary butyl hydroperoxide and tertiary butyl alcohol resulting from isobutane oxidation can be used in the process of this invention without requiring any other significant processing, e.g., purification step.
• isobutane is oxidized to give a mixture of tertiary butyl hydroperoxide and tertiary butyl alcohol by various methods.
• isobutane can be oxidized noncatalytically in the liquid phase with a free oxygen-containing gas, such as molecular oxygen and using reaction temperatures, for example, in the range from about 100C. to about 150C. and pressures above about 400 psig.
• the complex isobutane oxidation product mixture comprising tertiary butyl hydroperoxide, tertiary butyl alcohol and small amounts, e.g., less than about 5 percent by weight each, of various other components such as acetone, water, carbon dioxide, formic acid, methanol, isobutanol, etc., can be used, without further significant processing, as the source of at least a major portion, preferably at least about percent by weight and more preferably essentially all, of the tertiary butyl hydroperoxide used as oxidant and peroxy compound in the present invention without sacrificing oxidation efficiency.
• a portion of this isobutane oxidation product mixture may be used to prepare the molybdenum-containing catalyst in situ, e.g., in the presence of the sulfur-containing hydrocarbon material.
• the tertiary butyl alcohol in the complex product mixture from isobutane oxidation promotes the sulfur oxidation by reducing the viscosity of the oxidation reaction mass.
• tertiary butyl alcohol is used as an oxidation solvent in the present process, from about 5 parts to about 2,000 parts, preferably from about 50 parts to about 2,000 parts, more preferably from about 50 parts'to about 1,000 parts, by weight of alcohol is present per parts of sulfur-containing hydrocarbon material.
• this alcohol as a solvent in the oxidation step produces the same reaction efficiency and degree of desulfurization as when a more inclusive aromatic hydrocarbon solvent, such as benzene, is used.
• tertiary butyl alcohol rather than an extraneous oxidation solvent has a substantial processing benefits, e.g., the tertiary butyl hydroperoxidealcohol-containing mixture from isobutane oxidation can be used without further processing to remove the alcohol. In addition, no solvent other than tertiary butyl alcohol need be removed from the hydrocarbon material after sulfur oxidation.
• At least a portion of the tertiary butyl alcohol product from the sulfur oxidation step can be dehydrated to isobutylene which can be dimerized to form diisobutylene.
• the latter has many uses, for example, as an octane improver in gasoline.
• the tertiary butyl alcohol dehydration may be carried out using conventional procedures.
• the dehydration may take place in the liquid, vapor or mixed liquidvapor phase and is preferably catalyzed.
• the catalysts which are known to promote the dehydration of alcohols such as tertiary butyl alcohol are acidic catalysts such as various Bronsted and Lewis Acids; silica, alumina and silica-alumina based solid acids; sulfuric acid; acidic ion exchange resins; acidic zeolites and the like.
• reaction temperatures may range from about 200F. to about 800F., preferably from about 250F. to about 600F.
• reaction pressures may range from about atmospheric pressure to about 500 psig.
• Liquid phase alcohol dehydration may be carried out at a temperature in the range from about 20F. to about 300F., preferably from about 100F. to about 250F., at a pressure sufiiciently high to maintain the liquid phase in the reactor, e.g., typically in the range from about atmospheric pressure to about 1,000 psig. or higher.
• the weight hourly space velocity may vary over a broad range depending on the other reaction conditions and conversions desired.
• the dehydration reaction is carried out at a weight hourly space velocity in the range from about 1 to about 30, preferably from about 2 to about 10.
• the isobutylene can be dimerized to form diisobutylene, by any one of a number of procedures well known in the art.
• the isobutylene dimerization may be made to occur in the liquid vapor or mixed liquid-vapor phase and is preferably catalyzed.
• the catalysts which are useful in the dimerization reaction are Bronsted acids; sulfuric acid; phosphoric acid; silica, alumina and silica alumina based solid acids; acidic ion exchange resins and the like, as well as Ziegler-Natta catalysts and transition metal complex catalysts.
• the reaction temperature may range from about F. to about 450F., preferably from about 40F.
• typical dimerization temperatures range from about 0F. to about 450F. at a pressure sufficient to maintain the reactant in the liquid phase, e.g., from about atmospheric pressure to about 1,000 psig. or more.
• the weight hourly space velocity is typically in the range from about 1 to about 50, preferably from aboutto about 30.
• the hydrocarbon material is sent to a sulfur removal step such as that described previously.
• Conventional procedures e.g., flashing, stripping, distillation and the like may be employed to recover a hydrocarbon material having reduced sulfur content.
• the hydrocarbon material employed was a benzene soluble petroleum vacuum still residuum (lnitial Boiling Point 610F., 15 percent overhead 962F.) having the following composition.
• a soluble, i.e., homogeneous, oxidation catalyst was prepared by combining 0.74 weight percent molybdenum powder with tertiary butyl hydroperoxide in the presence of tertiary butyl alcohol and a mixture of C to C gylcols containing from 4 to 6 hydroxyl group per molecule wherein at least one of the hydroxyl groups was primary.
• the weight ratio of tertiary butyl hydroperoxide to tertiary butyl alcohol to glycols was about 2.l:4:l. This combination was heated to reflux temperature with constant stirring and maintained at this temperature until all the molybdenum had dissolved.
• Tertiary butyl hydroperoxide was used as the oxidant to oxidize the sulfur impurities in the hydrocarbon material. This oxidant was used in the form of a commercially available mixture containing about percent tertiary butyl hydroperoxide. Benzene was used as a solvent in the oxidation reaction and amounted to about 50 percent by weight of the oxidation reaction mixture.
• the oxidation reaction mixture was formed by combining the hydrocarbon material, benzene catalyst and tertiary butyl hydroperoxide with constant stirring to insure uniformity. This mixture contained 3.6 moles of tertiary butyl hydroperoxide per mole of sulfur and 187 ppm. of molybdenum.
• the remaining hydrocarbon product was cooled and placed in a glass vessel which itself was in a salt bath. This material was heated to a temperature within the range from 750F. to 800F. and maintained at this temperature for 4 hours. Throughout this period of time, hydrogen gas at atmospheric pressure was sent through the glass vessel. At the end of 4 hours, the liquid product was sampled and analyzed for sulfur content. lt was determined that the above processing had removed about 50 percent of the sulfur which was originally contained in the vacuum residuum.
• the hydrocarbon material used was the same as the benzene soluble petroleum vacuum still residuum employed in Example I.
• the oxidation catalyst used was prepared in the same mannerand had the same compolll sition as the catalyst used in Example I.
• Tertiary butyl hydroperoxide was used as oxidant and tertiary butyl alcohol, amounting to about 50 percent by weight of the oxidation reaction mixture, was used as oxidation solvent.
• the tertiary butyl hydroperoxide employed as an oxidant in this example was the product of liquid phase, noncatalytic oxidation of isobutane.
• the tertiary butyl hydroperoxide used was present in a mixture of 42.1 percent by weight tertiary butyl hydroperoxide, about 52 percent by weight tertiary butyl alcohol and 5.9 percent by weight of other impurities such as, acetone, water, carbon dioxide, formic acid, methanol and isobutanol.
• the oxidation reaction mixture was formed by combining the hydrocarbon material, tertiary butyl alcohol solvent, catalyst and tertiary butyl hydroperoxide with constant stirring. It was determined that not all of the hydrocarbon material was soluble in the tertiary butyl alcohol. This mixture contained 3.6 moles of tertiary butyl hydroperoxide per mole of sulfur and 80 ppm. of molybdenum.
• This reaction mixture was placed in equipment similar to that described in Example I and heated to a temperature of about 82C. which caused the reaction mixture to reflux. This temperature was maintained for 7.5 hours to effect sulfur oxidation. After this period of time, the product was stripped free of essentially all tertiary butyl alcohol and lighter components.
• the remaining hydrocarbon product was cooled and placed in a glass vessel similar to that described in Example I. This product was heated to a temperature within the range from 734F. to 750F. and maintained at this temperature for 2 hours. Throughout this period of time, hydrogen gas at atmospheric pressure was sent through the glass vessel. At the end of two hours, the liquid product was sampled and analyzed for sulfur content. It was determined that the above processing had removed about 50 percent of the sulfur which was originally contained in the vacuum.
• both Examples I and I] show desulfurization using the improved oxidation catalyst disclosed herein.
• this catalyst provides for an improved rate of oxidation and thus can make possible reduced reaction times for the sulfur oxidation of the present invention.
• Examples I and II illustrate the surprising discovery that tertiary butyl alcohol, admittedly a less inclusive solvent than benzene for certain components of heavy hydrocarbon materials, is as effective as benzene when used as solvent for oxidation of sulfurcontaining heavy hydrocarbon material.
• the use of tertiary butyl alcohol as oxidation solvent has significant and substantial benefits, particularly when tertiary butyl hydroperoxide is used as oxidant.
• tertiary butyl hydroperoxide is decomposed, tertiary butyl alcohol is formed. This decomposition product, i.e., tertiary butyl alcohol, must be removed from the final hydrocarbon product of reduced sulfur content.
• benzene is used as oxidation solvent
• additional processing equipment may be necessary to separate the benzene from the decomposition product tertiary butyl alcohol.
• the oxidation solvent and oxidant decomposition product are one and the same compound, i.e., tertiary butyl alcohol, additional processing required to l2 recover useable and/or saleable products is minimized. This processing benefit can be taken advantage of because of the discovery that tertiary butyl alcohol performs as well as benzene as an oxidation solvent in the present invention.
• Example II when compared to Example I, demonstrates that impure tertiary butyl hydroperoxide obtained from isobutane oxidation may be used as oxidant without adversely affecting the sulfuroxidation of the present invention.
• tertiary butyl hydroperoxide derived from isobutane oxidation may be used as oxidant rather than pure or near pure tertiary butyl hydroperoxide, such as used in Example I.
• a desulfurization process for producing a hydrocarbon material of reduced sulfur content wherein at least a portion of the sulfur in a sulfur-containing hydrocarbon material is preferentially oxidized and the oxidized sulfur-containing hydrocarbon material is further processed by means of a sulfur reducing step, the improvement which comprises preferentially oxidizing said sulfur with an oxidant selected from the group consisting of organic peroxides, organic hydroperoxides, organic peracids, and mixtures thereof in the presence of a molybdenum-containing catalyst prepared by a method which comprises interacting molybdenum metal with at least one peroxy compound in the presence of at least one saturated alcohol having from one to four carbon atoms per molecule to solubilize at least a portion of said molybdenum metal, said catalyst being present in an amount sufficient to promote the preferential oxidation of said sulfur.
• tertiary butyl hydroperoxide is derived from oxidation of isobutane and said primary alcohol is a mixture of polyhydroxy alcohols which have a molecular weight in the range from about 200 to about 300 and contain from about four to about six hydroxy groups, said poly-hydroxy alcohols being derived from propylene epoxidation with tertiary butyl hydroperoxide.
• a process for producing a hydrocarbon material of reduced sulfur-content which comprises:
• a molybdenumcontaining catalyst prepared by a method which comprises interacting molybdenum metal with at least one peroxy compound in the presence of at least one saturated alcohol having from one to four carbon atoms per molecule to solubilize at least a portion of said molybdenum metal, said catalyst being present in an amount sufficient to promote the preferential oxidation of said sulfur;
• step (2) comprises:

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Cited By (51)

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• 1972
  • 1972-06-30 US US00268160A patent/US3816301A/en not_active Expired - Lifetime
• 1973
  • 1973-05-29 GB GB2538373A patent/GB1425850A/en not_active Expired
  • 1973-06-20 CA CA174,524A patent/CA1007253A/en not_active Expired
  • 1973-06-28 JP JP48073227A patent/JPS4952803A/ja active Pending

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