DE2927685A1 - CATALYST - Google Patents

Description

catalyst

The invention relates to a catalyst which is particularly suitable for converting mercaptans that are difficult to oxidize, which are contained in an acidic petroleum distillate. Process for the treatment of sour petroleum distillates in which the distillate is treated in contact with an oxidation catalyst in the presence of an oxidizing agent under alkaline reaction conditions are known and are used in petroleum refineries practiced widely. These procedures are typically tailored to be more damaging to oxidation Mercaptans, which are contained in an acidic petroleum distillate, cause harmless disulfides to form, and this Procedure is commonly referred to as sweetening. Depending on the source of the petroleum from which the acidic distillate came, the boiling range of the distillate itself and, if applicable, the method of processing the petroleum to form the distillate the distillates vary greatly with regard to the concentration, the molecular weight and the complexity of the contained therein Mercaptans, and the sweetening method will vary accordingly.

One such method relates to petroleum distillates containing olefin. If these distillates have to be kept in stock for a long time, they advantageously contain an antioxidant to prevent gum formation. The inhibitor is typically an oil soluble phenylenediamine. If the olefin-containing distillates continue to have a relatively small concentration

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tration of the more easily oxidizable mercaptens, the phenylenediamine acts as a homogeneous oxygen transfer agent and promotes the oxidation of mercaptans and the formation of disulfides in the presence of an alkaline agent. It it should be noted that at least one third of the mercaptans are caused by interaction with the olefin content of the acidic distillate is consumed. The process is commonly referred to as inhibitor sweetening. The homogeneous phenylenediamine is not recoverable, but is consumed in the sweetening process, and when the required amount of phenylenediamine, to an economical one To cause the rate of oxidation to become excessively large, the process becomes ineffective as a sweetening process, and other means must be used. It is known, that inhibitor sweetening, which is essentially a batch type process, which is more for the treatment of sour distillates in storage, only works with olefin-containing distillates, the olefin being essential for the inhibitor sweetening process is. The stored distillate can be sweetened for a period of time usually measured in hours or days, depending on the complexity and concentration of the mercaptans it contains. Although certain quaternary ammonium halides are associated with the homogeneous Phenylenediamine catalysts were used to start the sweetening process as shown in U.S. Patent 3,164,544 the restrictions of inhibitor sweetening also apply to this process. Thus, inhibitor sweeteners are generally ineffective with regard to acidic petroleum distillates which contain mercaptans other than primary and secondary mercaptans, and it is steep

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ineffective with respect to petroleum distillates containing more than about 150 ppm mercaptan sulfur.

Acid petroleum distillates that do not react to inhibitor sweeteners, i.e. those that contain higher molecular weight and / or mercaptans More complex mercaptans or containing higher concentrations of mercaptans are usually in contact with a heterogeneous Treated metal phthalocyanine catalyst dispersed in an aqueous alkaline solution to give a sweetened product to surrender. The acidic distillate and the aqueous alkali solution containing the catalyst result in a liquid-liquid system, wherein mercaptans at the interface of the mutually immiscible solutions in the presence of an oxidizing agent, usually Air, to be converted into disulfides. This liquid-liquid system becomes immutable in a continuous Processes are used that require significantly less contact time than is required for inhibitor sweetening is. The metal phthalocyanine catalyst that is recovered and recycled for continued use is not for use in conjunction with an olefinic petroleum distillate limited, but is equally effective with olefin-free distillates to produce a doctor-sweet product.

Some of the higher boiling acidic petroleum distillates, which generally boil above about 135 C, contain highly hindered ones branched and aromatic thiols and / or higher molecular weight tertiary and polyfunctional mercaptans, which are at most only partially in the catalyst-containing alkali solution of the liquid-liquid treatment system are soluble. Acidic earth

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Oil distillates containing these more difficultly oxidizable mercaptens become more effective in contact with a metal phthalocyanine catalyst treated, for example as an impregnation on an adsorptive carrier with a large surface, usually on activated carbon. The distillate is in contact with the supported metal phthalocyanine catalyst Treated oxidation conditions in the presence of an alkaline reagent. One such method is disclosed in U.S. Patent No. 2,988,500 described. The oxidizing agent is most often air mixed with the distillate to be treated, and that alkaline reagent is most often an aqueous caustic alkali solution, which is fed continuously or intermittently to the process, depending on what is required for the catalyst keep in a condition wetted with alkali.

It is the object of the invention to provide a new catalytic composition to get that particularly useful in treatment acidic petroleum distillates, which contain the more difficult to oxidize mercaptans.

According to a broad aspect, the invention relates to a catalyst, the one metal chelate mercaptan oxidation catalyst and a quaternary ammonium compound impregnated on a solid adsorptive support, said quaternary Ammonium compound the general formula

RNR ₀
R.

has, where R is a hydrocarbon radical with up to 20 Koh is lenstoffatomen and an alkyl, cycloalkyl, aryl, AIk-

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aryl or aralkyl group, R _{1 is} an essentially straight-chain alkyl group with 5 to 20 carbon atoms, R "is an aryl, alkaryl or aralkyl group and X is chloride, bromide, iodide, fluoride, nitrate, nitrite -, sulfate, phosphate, acetate, citrate, tartrate or hydroxide anion means.

The metal chelate-mercaptan oxidation catalyst used as a component of the catalyst of the invention can be any of the various metal chelates found in the treatment art to be effective for catalyzing oxidation of mercaptans in an acidic petroleum distillate with the formation of polysulphide oxidation products are known- These chelates include, for example, the metal compounds of tetrapyridinoporphyrazine described in US Pat. No. 3,980,582 such as cobalt tetrapyridinoporphyrazine, porphyrin and metal porphyrin catalysts such as those disclosed in U.S. Patent No. 2,966,453 are described, such as, for example, cobalt tetraphenylporphyrinsulfonate, corrin iodine catalysts, as described in US Pat 3,252,892 are described, such as cobalt corrinsulfonate, and the organometallic chelate catalysts as described in US Pat U.S. Patent No. 2,918,426 as the condensation product of an aminophenol and a Group VIII metal. Metal phthalocyanines are a preferred class of metal chelate mercaptan oxidation catalysts.

The metal phthalocyanines generally used as a mercaptan oxidation catalyst are, for example, magnesium phthalocyanine, Titanium phthalocyanine, hafnium phthalocyanine, vanadium phthalocyanine, tantalum phthalocyanine, molybdenum phthalocyanine

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cyanine, manganese phthalocyanine, iron phthalocyanine, cobalt phthalocyanine, Nickel phthalocyanine, platinum phthalocyanine, palladium phthalocyanine, Copper phthalocyanine, silver phthalocyanine, zinc phthalocyanine and tin phthalocyanine. Cobalt phthalocyanine and vanadium phthalocyanine are particularly preferred. The MetaIT-phthalocyanine is most commonly used as a derivative thereof, the commercially available sulfonated ones Derivatives such as cobalt phthalocyanine monosulfonate, cobalt phthalocyanine disulfonate or a mixture thereof are particularly preferred. The sulfonated derivatives can, for example produced by reacting cobalt, vanadium or other metal phthalocyanine with fuming sulfuric acid will. Although the sulfonated derivatives are preferred, other derivatives, especially the carboxylated ones, can of course also be used Derivatives, can be used. The carboxylated derivatives are easily produced by the action of trichloroacetic acid on the metal phthalocyanine.

The quaternary ammonium compound as a component of the catalyst according to the invention has the general structural formula

R-N-R

H,

wherein R is a hydrocarbon radical with up to 20 carbon atoms and is an alkyl, cycloalkyl, aryl, alkaryl or aralkyl group, R- is an essentially straight-chain alkyl group with 5 to 20 carbon atoms, R _{2 is} an aryl, alkaryl or Aralkyl group and X is a halide, nitrate, nitrite, sulfate, phosphate, acetate,

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Is citrate, tartrate or hydroxide anion. R ₁ is preferably an alkyl group having 12 to 18 carbon atoms, R ~ is preferably a benzyl group, and X is preferably chloride or hydroxide. Preferred quaternary ammonium compounds are thus, for example, quaternary ammonium chlorides and quaternary ammonium hydroxides such as benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, benzyldimethylhexadecylammonium chloride, Benzyldimethyloctadecylammoniumchlorid, Benzyldimethyldodecylammoniumhydroxid, Benzyldimethyltetradecylammoniumhydroxid, Benzyldimethylhexadecylammoniumhydroxid, Benzyldimethyloctadecylammoniumhydroxid and the like. Other suitable quaternary ammonium compounds are, for example Phenyldialkylpentylammoniumchlorid, Phenyldialkylhexylammoniumchlorid, Phenyldialkyloctylammoniumchlorid, Phenyldialkyldecylammoniumchlorid, Phenyldialkyldodecylammoniumchlorid, Phenyldialkyltetradecy1ammoniumchlorid, Phenyldialkylhexadecylammoniumchlorid, Phenyldialkyloctadecylammoniumchlorid, Phenyldialkyleicosylammoniumchlorid, Naphthyldialkylpentylammoniumchlorid, Naphthyldialkylhexylammoniumchlorid, Naphthyldialkyloctylammoniumchlorid, Naphthyldialkyldecylammoniumchlorid, Naphthyldialkyldodecylammoniumchlorid, Naphthyldialkyltetradecylammoniumchlorid, Naphthyldialkylhexadecylammoniumchlorid, Naphthyldialkyloctadecylammoniumchlorid, Benzyldialkylpentylammoniumchlorid, Benzyldialkylhexylammoniumchlorid, Benzyldialkyloctylammoniumchlorid, Benzyldialkyldecylammoniumchlorid, Benzyldialkyleicosylammoniumchlorid, ToIyldialkylpentylammoniumchlorid, ToIyldialkylhexylammoniumchlorid, Tolyldialkyloctylammoniumchlorid, Tolyl dialkyldecyl

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ammonium chloride, tolyldialkyldodecylammonium chloride, tolyldialkyltetradecylammonium chloride, TolyldialkyIhexadecylammoniumchlorid, Tolyldialkyloctadecylammonium chloride, tolyldialkyleicosylammonium chloride, Diphenylalkylpentylammoniumchlorid, DiphenylalkyIhexylammoniumchlorid, Diphenylalkyloctylammoniumchlorid, Diphenylalkyldecylammonium chloride / Diphenylalkyldodecylammonium chloride, Dipheny! Alkyltetradecylammonium chloride, Diphenylalkylhexadecylammonium chloride, diphenylalkyloctadecylammonium chloride and Dipheny lalky leicosylammoniumchlorid as well as the corresponding fluorides, bromides, iodides, sulfates, nitrates, Nitrites, phosphates, acetates, citrates, tartrates and hydroxides, in which the alkyl radical is a methyl, ethyl or propyl group is.

The preferred benzyldimethylalkylammonium chlorides are commercially available from Mason Chemical Company under the tradename Maquats. However, these Benzyldimethylalkylammoniumchloride can also be prepared by first ammonia and a C _{1 n} -C ₁₀ carboxylic acid in contact with

Iz Io

Silica gel is reacted at about 500 ° C with the formation of a C ^ 2 ~ ^c -io ~ ^N i ^tr: il ^s . The nitrile is then reduced with hydrogen in contact with a nickel catalyst at about 140 ° C. The resulting C ₁₂ -C ₁ Q-AmXn is separated from the reaction mixture and reacted with a two molar excess of methyl chloride. After neutralization of the reaction mixture, the amine is further reacted with one molar equivalent of benzyl chloride to give the desired benzyldimethylalkylammonium chloride. The methyl chloride as well as the benzyl chloride is expediently with the amine in methanol solution at a temperature at about

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150 C implemented. The product can be used as is or it can be further treated over activated carbon, to remove impurities.

The solid adsorbent carrier used herein can be any of the known solid adsorbent materials commonly used as catalyst supports. Preferred Adsorbent materials are, for example, the various activated carbons that are produced by the decomposition of the distillation of wood, Peat, lignite, nutshells, bones and other carbonaceous materials are produced, and preferably those Activated carbons that have been heat-treated and / or chemically treated to form a highly porous particle structure with increased adsorbent capacity to form and which are commonly referred to as activated carbon or activated carbon. These adsorbent materials also include naturally occurring clays and silicates, such as diatomaceous earth, fuller's earth, kieselguhr, attapulgus clay, Feldspar, montmorillonite, haloysite and kaolin, and also the naturally occurring or synthetically produced refractory inorganic oxides such as alumina, silica, zirconium oxide, thorium oxide and boron oxide or combinations the same as silica-alumina, silica-zirconia and alumina-zirconia. Any special solid adsorbent material is selected taking into account its stability under the conditions of its intended use. For example, when treating an acidic petroleum distillate as described above, the solid adsorbent should carrier material in the petroleum distillate for those in the treatment zone the prevailing alkaline reaction conditions

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borrowed, and otherwise inert to the petroleum distillate. In the latter case, charcoal, and especially activated charcoal, is because of their capacity for and because of their metal phthalocyanine Stability under treatment conditions preferred.

The quaternary ammonium compounds according to the invention and the metal chelate-mercaptan oxidation catalyst, especially the metal phthalocyanines, are easily adsorbent on the solid Carrier adsorbed. The quaternary ammonium salt can be up to 50% by weight of the catalytic composition turn off. Included in the sweetening process under consideration here the quaternary ammonium salt suitably from 1 to 50% by weight and preferably from 5 to 35% by weight of the composition. In general Up to about 25% by weight of metal phthalocyanine can be adsorbed on the solid adsorbent support and form still a stable catalytic composition. A minor amount in the range of 0.1 to 10% by weight generally constitutes a suitably active catalyst, with a range of 0.1 to 2.0% by weight being generally preferred. The activity advantage obtained with metal phthalocyanine concentrations above 2% by weight has so far not guaranteed even the use of higher concentrations. With regard the substantial increase in activity resulting from the use of the quaternary ammonium salt according to the invention in connection with minimal metal phthalocyanine concentrations, however, it is believed that the higher concentration becomes effective, a further increase in the rate of mercaptan oxidation to promote, especially when taking into account the hardness, in order to treat acidic petroleum distillates.

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The quaternary ammonium compound and the metal chelate compounds can be used as an impregnation on the solid adsorbent carrier in any conventional or other convenient manner, and these components can be used as an impregnation on the carrier simultaneously from a common aqueous or alcoholic solution and / or dispersion of these components or applied separately and in any desired order. The impregnation process can be carried out under Using conventional methods, the carrier can be in the form of spheres, pills, pellets, granules or other particles of uniform or irregular shape and size soaked, suspended or immersed one or more times or is otherwise immersed in an aqueous or alcoholic impregnation solution and / or dispersion in order to adsorb a certain amount of the ammonium compound and the metal chelate components thereon. A preferred method consists in the use of a rotary evaporator with a steam jacket. The adsorbent carrier is in the impregnation solution and / or dispersion contained in the dryer, and the carrier is immersed therein by the rotary motion of the dryer. Evaporation of the solution in contact with the rolled support is due to the application of water vapor in accelerated by the dryer jacket. In either case, the resulting composition is left under ambient temperature conditions dry or dry them at elevated temperature in an oven or in a stream of hot gases or in any one other suitable way.

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A convenient alternative method for adsorbing the ammonium compound and the metal chelate components on the solid adsorbent support is that of first having the support arranged as a fixed layer in a treatment zone or treatment chamber for the acidic petroleum distillate and then passing the ammonium compound metal chelate impregnation solution and / or dispersion through the bed to form the catalyst in situ. This method allows returning the solution and / or dispersion one or more times in order to achieve a desired concentration of the ammonium compound and to get the metal chelate components on the adsorbent support. With yet another alternative method can the adsorbent beforehand in the treatment zone or treatment chamber are arranged, and then the zone or chamber is filled with the impregnation solution and / or dispersion, to soak the wearer for a predetermined time.

In the process of sweetening an acidic petroleum distillate, it has heretofore been the practice to oxidize the mercaptans contained therein in the presence of an alkaline reagent. A supported mercaptan oxidation catalyst is typically saturated with the alkaline reagent first, and then becomes the alkaline reagent Reagent in contact with the catalyst layer continuously or intermittently, as required, in admixture with the acidic petroleum distillate. Any suitable alkaline reagent can be used. An alkaline metal hydroxide in aqueous solution such as sodium hydroxide in aqueous solution is most commonly used. The solution can further comprise a solubilizer in order to dissolve the mercaptan

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ability to promote such as alcohol and especially methanol, ethanol, n-propanol or isopropanol and also phenols or cresols. A particularly preferred alkaline reagent is an aqueous caustic alkali solution containing 2 to 30% by weight Includes sodium hydroxide. The solubilizer, if used, is preferably methanol and the alkaline solution may suitably comprise 2 to 100% by volume thereof. Sodium hydroxide and potassium hydroxide are the preferred alkaline reagents, but others such as lithium hydroxide, rubidium hydroxide and cesium hydroxide can also be used. can be used appropriately. When the catalytic composition of the invention has a quaternary ammonium hydroxide component those distillates which contain the more easily oxidizable mercaptans can be used in the absence treated by added alkaline reagent.

The method according to the invention can be carried out according to known treatment methods be performed. The process is usually carried out under ambient temperature conditions, although convenient higher temperatures up to about 105 C can be used.

Pressures up to 69 atm are applicable, although atmospheres or
pressure / essentially atmospheric pressure are entirely suitable. Contact times corresponding to a liquid hourly space velocity of 0.5 to 10 or more are effective to achieve a desired reduction in the mercaptan content of an acidic petroleum distillate, an optimal contact time depending on the size of the treatment zone, the amount of catalyst contained therein and the character of the treated Depends on the distillate.

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I /

As stated above, the sour petroleum distillate is sweetened by oxidizing its mercaptan content to disulfides. Thus, although the process is carried out in the presence of an oxidizing agent, preferably air Oxygen or other oxygen-containing gases can be used can. The acidic petroleum distillate can go up or down be sent through the catalyst layer, the acidic Petroleum distillate can contain sufficient entrained air but generally added air is mixed with the distillate and introduced into the treatment zone at the same time as it. In some cases it can be advantageous to have the air separately and in countercurrent to that supplied separately from it Introduce distillate into the treatment zone.

The catalyst composition of the invention is both active as well as stable. Accordingly, the catalyst can be used in a fixed layer can be used to treat large volumes of sour petroleum distillate, especially those distillates which make the more difficult to oxidize mercaptans contain. As mentioned above, the quaternary ammonium compound and the metal phthalocyanine components of the catalyst of the invention lightly on the solid adsorbent support adsorbed by the catalyst. If thus some of the quaternary ammonium compound or the metal phthalocyanine components is temporarily leached from the carrier and carried away in the reaction stream, this amount can easily be returned to the catalyst in situ by one or both of these components, for example in Mix with an alkaline reagent in the sweetening process

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introduces to be adsorbed on the solid adsorbent in the treatment zone.

The following example serves to further explain the invention.

example

In the preparation of the catalyst according to the invention, an impregnation solution and / or dispersion was added by adding 0.75 g of cobalt phthalocyanine monosulfonate and 23.5 g of a 50% alcoholic solution of dimethylbenzylalkylammonium chloride to 250 ml of deionized water obtained in a steam rotary evaporator. Benzyldimethylalkylammonium chloride consisted of benzyldimethyldodecylammonium chloride (61%), benzyldimethyltetradecylammonium chloride (23%), benzyldimethylhexadecylammonium chloride (11%) and benzyldimethyloctadecylammonium chloride. 250 cm of activated coal particles of 10 χ 30 mesh (US sieve series) were in the Immersed the impregnation solution and rolled it for 1 hour by rotating the evaporator. Water vapor was afterwards fed to the evaporator jacket, and the impregnation solution was in contact with circulating coal particles for 1 hour evaporated to dryness.

The catalyst thus prepared, hereinafter referred to as catalyst A, was subjected to a comparative evaluation test compared with a standard catalyst. The standard catalyst, hereinafter referred to as catalyst B. was prepared essentially as described above, but without the benzyldimethylalkylammonium chloride component.

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The comparative evaluation test was that an acid kerosene passed down through 100 cm of catalyst in a fixed layer arranged in a vertical tubular reactor was, was led. The kerosene was at a liquid hourly space velocity of 0.5 under 3.4 atm Air supplied, which was enough, about 1.5 times the amount of to deliver the stoichiometric amount of oxygen required was to oxidize the mercaptans contained in the kerosene. In each case, the catalyst layer was initially used 10 cm of an 8% aqueous sodium hydroxide solution was wetted, and 10 cm of this solution were then in 12 hours Introduced into the catalyst bed at intervals in admixture with the kerosene charge. The treated kerosene, that at first Containing 533 ppm of mercaptan sulfur was periodically checked for of mercaptan sulfur analyzed. The mercaptan sulfur content of the treated kerosene was plotted against the treatment time in hours, a curve being obtained from which the values listed in the table below were taken.

Tabel

Time, hours Mereaptane sulfur, Weight ppm Catalyst A Catalyst B 50 5 36 1OO 9 31 150 11 31 200 11 31 250 11 31

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Claims (11)

Dr. Hans-HeinricL Willrath Dr. Dieter Weber Diploma in Phys. Klaus Seiifert PATENT LAWYERS D - 6200 WIESBADEN 1 July 4, 1979 P.O. Box 6145 Gustav-Freytag-Strasse 25 Dr. We / Wn ® (06121) 372720
Telegram address: WILLPATENT Telex: 4-186247 Case 1846 UOP Inc., Ten UOP Plaza - Algonquin & Mt. Prospect Roads, Des Piaines, Illinois 60016, USA catalyst Priority; Serial TSFos. 927 317 and 927 318 dated July 24, 1978 in USA Additional registration to P 29 05 581.0-44 Claims Catalyst for carrying out the process according to the patent . ... ... (patent application P 29 05 581.0-44) from a solid adsorptive carrier with an impregnation of a metal 909886/0657 chelate mercaptan oxidation catalyst and a quaternary Airanoniumverbindungen, characterized in that the quaternary Ammonium compound the general formula RNR ₂
R. where R is a hydrocarbon radical with up to 20 carbon atoms, which is an alkyl, cycloalkyl, aryl, alkaryl or aralkyl group, R _{1 is} an essentially straight-chain alkyl group with 5 to 20 carbon atoms, R "is an aryl, Denotes alkaryl or aralkyl group and X denotes a chloride, bromide, iodide, fluoride, nitrate, nitrite, sulfate, phosphate, acetate, citrate, tartrate or hydroxide anion. 2. Catalyst according to claim 1, characterized in that its quaternary ammonium compound is 1 to 50% by weight, preferably Constitutes 5 to 35% by weight of the catalyst. 3. Catalyst according to claim 1 and 2, characterized in that R _{1 is} a substantially straight-chain alkyl group having 12 to 18 carbon atoms. 4. Catalyst according to claim 1 to 3, characterized in that Rj is a benzyl radical. 5. Catalyst according to claim 1 to 4, characterized in that its quaternary ammonium compound is a quaternary ammonium halide, is preferably a quaternary ammonium chloride. 6. Catalyst according to claim 1 to 5, characterized in that its quaternary ammonium chloride benzyldimethyldodecylammonium chloride, Benzyldimethyltetradecylammonium chloride, benzyldi- 909886/0657 methylhexadecyl ammonium chloride and / or benzyldimethyloctadecyl ammonium chloride is. 7. Catalyst according to claim 1 to 6, characterized in that its quaternary Amitioniuinverbindungen a quaternary ammonium hydroxide is. 8. Catalyst according to claim 1 to 7, characterized in that its quaternary ammonium hydroxide benzyldimethyldodecylammonium hydroxide, Benzyldimethyltetradecylammonium hydroxide, benzyldimethylhexadecylammonium hydroxide and / or benzyldimethyloctadecylammonium hydroxide. 9. Catalyst according to claim 1 to 8, characterized in that its solid adsorptive carrier is activated carbon. 10. Catalyst according to claim 1 to 9, characterized in that its metal chelate mercaptan oxidation catalyst a metal phthalocyanine, preferably a vanadium phthalocyanine or a cobalt phthalocyanine, particularly cobalt phthalocyanine monosulfonate is. 11. Catalyst according to claim 1 to 10, characterized in that its metal chelate-mercaptan oxidation catalyst 0.1 to 10,
preferably 0.1 to 2% by weight of the catalyst. 909886/0657