MXPA99007047A - Method for producing halogen-free reactive polyisobutene - Google Patents

Abstract

The invention relates to a method for producing halogen-free, reactive polyisobutene with a terminal double-bond content of over 50 mol%and an average molecular weight of 2,800 - 10,000 Dalton by cationic polymerization of isobutene or isobutene-containing hydrocarbon mixtures in a liquid phase, wherein polmerization is carried out at a temperature of -30°C to +40°C in the presence of a heterogeneous polymerization catalyst from one or several oxides of the elements of the 5th and 6th subgroup of the periodic table of elements or in the presence of a heterogeneous polymerization catalyst containing one or more oxidic compounds of one or more elements of the 5th and 6th subgroup of the periodic table of elements on an oxygen-containing zircon compound of various non-zeolitic oxidic supporting material, wherein said catalyst contains no technically active quantities of halogen.

Description

PREPARATION OF REAGENT, HALOGEN FREE POLYISOBUTENUM The present invention relates to a process for preparing reactive polyisobutene, free of halogen, with a content of terminal double bonds of more than 50 mol% and an average molecular weight LMn of 280-10000 daltons by cationic polymerization in liquid phase of isobutene or mixtures of hydrocarbons containing isobutene. The polymerization of isobutene produces an inseparable mixture of polyisobutenes, in which the position of the double bond varies between the individual polyisobutenes. The polyisobutenes of formula I. wherein n is the degree of polymerization which, in turn, is derived from the average molecular weight Mn of the prepared polyisobutene, which contains vinylidene type CC double bond which is also mentioned herein as an α-olefinic double bonds due to its position in the polyisobutene molecule. Accordingly, the double bonds in the polyisobutenes of formula II. they are referred to as β-olefinic. If the polymerization of isobutene is carried out without taking special measures, a random mixture is formed containing polyisobutenes having double bonds-olefinic, that is, double terminals ß-olefinic bonds and double bonds located more towards the interior of the molecule of polyisobutene. The content of terminal double bonds and the content of the β-olefinic double bond of a polyisobutene product prepared by a particular process are both reported in mole percent. Polyisobutenes having molecular weights of up to 100,000 daltons are known. These olefins are generally prepared by polymerization of isobutene catalyzed by Lewis acids using aluminum chloride, alkylammonium chloride or boron trifluoride as Lewis acid, as described, for example, in H. Güterboc, Polyisobutylene und Mischopolymerizate, p. . 77-104, Springer Verlag, Berlin, 1959. However, the resulting polymers have a relatively low vinylidene C-C terminal double bond content of less than 10 mol%.

In contrast, reactive polyisobutene (PIB) with molecular weights typically of 500-5000 daltons have a high content of terminal vinylidene groups of, preferably, more than 50 mol%. These reactive polyisobutenes are used as intermediates in the preparation of lubricants and motor fuel additives as described, for example, in DE-A 27 02 604. These additives are prepared by initial reaction of polyisobutene with maleic anhydride. The preferred reactive sites for this reaction are the vinylidene-type terminal double bonds, while the double bonds located further into the macromolecule react to a lesser degree, if they react, depending on their position in the molecule. The polyisobutenes / maleic anhydride formed adducts are then reacted with certain amines to give the corresponding additives. It is therefore absolutely necessary that the polyisobutenes used as starting materials for the aforementioned additives have a high content of terminal double bonds. The same applies for the preparation of the polyisobutenoamines of EP-A 244 616 which are also used as additives for motor fuels and which are prepared by hydroformylation of the reactive polyisobutene and the subsequent reductive amination of the resulting polyisobutene aldehyde. For this process, likewise, preference is given to using polyisobutene having a high content of terminal double bonds, but the β-olefinic polyisobutenes also give the desired product when the hydroformylation is carried out using cobalt catalysts, due to its isomerization activity in the double bond. The preparation of reactive polyisobutene by homogeneously catalyzed isobutene polymerization is already known. According to DE-A 27 02 604, for example, a polyisobutene product having a terminal double terminal bond content of up to 88% is obtained by reaction of polyisobutene in the presence of boron trifluoride. EP-A 145 235 teaches the polymerization of isobutene in the presence of a complex of boron trifluoride and a primary alcohol from -100 ° C to + 50 ° C to give products with similarly high contents of vinylidene double bonds. According to US-A 5 286 823, the highly reactive polyisobutene can also be prepared using complexes of boron trifluoride and secondary alcohols as catalysts. The disadvantages of this homogeneously catalyzed process are that the Lewis acid catalysts used are corrosive and that there is a risk that, apart from the desired reactive isobutene, halogenated polymeric by-products are formed which are almost inseparable from PIB and adversely affect the product. and the characteristics of GDP processing. In these processes the homogeneous catalyst is usually separated by quenching with a nucleophile to destroy the catalyst and subsequently separating the PIB from the extinguished mixture by extraction. These additional preparation steps are another disadvantage of the homogenously catalyzed PIB preparation process. WO 94/28036 describes, among others, the preparation of polyisobutene using heterogeneous catalysts similar to Lewis acids. The catalysts used are salts of the elements of transition groups III, IV, V and VI of the Periodic Table of the Elements whose salts are insoluble in the reaction medium, preferably halides, sulfates, perchlorates, trifluoro-ethanesulfonates, nitrates and flurosulfonates. thereof. In the examples of this application, only the halides of these elements are used as catalysts for the polymerization of isobutene. No information is given about the properties of the polyisobutene obtained in these examples in terms of their molecular weight or their content of terminal double bonds. The polymerization is terminated by adding methanolic ammonia solution to the reaction medium to destroy or at least substantially inactivate the catalysts in question.

The preparation of PIB using heterogeneous catalysts is also known. US-A 4 288 649 describes a process for preparing polyisobutene with an average molecular weight of > 1250 dalton by polymerization of mixtures of C4 hydrocarbons comprising isobutenes on halogenated alumina catalysts. These catalysts are prepared by treating the alumina with a halogenating agent, preferably with a chlorinating agent, in particular with carbon tetrachloride, at an elevated temperature. The disadvantage of this process is that some of the chlorine in the catalyst is transferred to the polymer that is formed. For example, the polymerization of a mixture of n-butane, isobutane and isobutene on a chlorinated alumina catalyst prepared in this way gives, after a reaction time of 2 hours, a polyisobutene product with a chlorine content of 46 ppm. US-A 4 326 920 describes a process for the polymerization of isobutene by using as the heterogeneous catalyst an oxidic support material, preferably silica, which has been activated with a metal chloride bound thereto, preferably with an aluminum chloride. Particular reference is given thereto to a SiO2-A1C12 catalyst in which the A1C12 groups are fixed to the Si02 support by means of oxygen bonds. The disadvantage of this process is that the obtained polyisobutene products have an extremely broad molecular weight distribution D, from 8 to 14, a low content of terminal double bonds and a chloride content in the ppm range. In addition, this process requires the presence of promoters such as water, alcohols, alkyl halides or hydrogen chloride to carry out a catalytic activity that is sufficient for industrial operation. Similar catalyst systems for the polymerization of isobutenes are described in WO 95/26815, WO 95/26816, WO 95/26814 and WO 96/26818. JP-A 139 429/1981 uses heterogeneous zirconium oxide and molybdenum oxide catalysts to prepare oligomers of isobutene with a molecular weight of less than 300 daltons. These catalysts can be mixed with aluminum fluoride to increase their activity. According to this publication, the reaction of a cut of C4 containing isobutane (composition: 46% isobutene, 28% 1-butene, 8% 2-butenes, 12% n-butane, 5% isobutane, 1% of 1,3-butadiene) on a Mo03 / Zr02 catalyst with a molybdenum content, calculated as Mo03, of 13% by weight, at 120 ° C, produces an oligomeric mixture of isobutene comprising 29% diisobutene, 49 % triisobutene and 19% tetraisobutene. NL-A 7 002 055 describes a process for preparing oligomers of isobutene in gas phase using a tin oxide / molybdenum oxide catalyst in silica to give a mixture of isobutene dimers, trimers and tetramers. EP-A 535 516 describes a catalyst for the preparation of ethylene polymers consisting of chromium oxide in a particular Si02 support material. This publication does not teach the preparation of low molecular weight reactive polyisobutene. GB-A 1 115 521 describes, among others, the polymerization of isobutene on Na-X zeolite loaded with a platinum compound. It produces essentially dimers and trimers of isobutene alone or with lower amounts of tetramers and higher polymers. No information is given about the molecular weight of the superiores polymers formed in this way and their content of terminal double bonds. The unpublished application PCT / EP 96/03441 describes a process for preparing low molecular weight, halogen-free, reactive, polyisobutene, using as a catalyst a support material comprising a zirconium compound containing oxygen and inpurified with various promoters. An object of the present invention is to find a process for preparing reactive polyisobutene, free of halogen, with a content of terminal double bonds of more than 50 mol%, a content of terminal double bonds and ß-olefinic double bonds of more than 80% mole and an average molecular weight of 280-10000 dalton using a heterogeneous catalyst. Another object of the present invention is to find heterogeneous catalysts which are suitable for this process and which make possible the operation of the process for preparing polyisobutenes in an economical manner. We have found that these objects are achieved by a process to prepare reactive polyisobutene, free of halogen, with a content of terminal double bonds of more than 50 mol% and an average molecular weight Mn of 280-10000 daltons by cationic polymerization in liquid phase of isobutene or mixtures of hydrocarbons containing isobutene, consisting of polymerization from -30 ° C to + 40 ° C in the presence of a heterogeneous polymerization catalyst containing one or more oxides of the elements of the transition groups V and VI of the Periodic Table of the Elements or in the presence of a catalyst heterogeneous polymerization comprising one or more oxidic compounds of one more elements of the transition groups V and VI of the Periodic Table of the Supported Elements in a non-zeolitic oxidic support material, which is not an oxygen-containing zirconium compound, the catalyst does not contain a technically effective amount of halogen. In contrast to the unpurified oxides of the individual support materials which are almost inactive as catalysts for the polymerization of isobutene or have only a very low catalytic activity, the catalysts to be used according to the invention have a good or very good activity and selectivity for the polymerization of polyisobutene to give polyisobutene reagents, of low molecular weight, with a content of terminal double bonds of more than 50 mol% and an average molecular weight of 280-10000 daltons. Since it is not necessary to add halogenated compounds to the catalysts to be used according to the invention to achieve high activity and selectivity, these catalysts provide an inexpensive way to prepare halogen-free PIB. Since the method of preparation of the catalysts to be used according to the invention and the chemical and physical analytical data of these catalysts suggest that the support material present in these catalysts is in the form of the oxidic compounds of the support components Individuals, for the present application, for simplicity, use is made of the terms oxidic support material or individual oxides of these support materials or the support components that constitute the support material. For the purposes of the present invention, zeolites or materials having properties similar to zeolites, such as silicon aluminum phosphates, (SAPOS) mesoporous silicates materials or clays, such as bentonites, montmorillonites, kaolin, which are collectively referred to as "" zeolitic materials "in the present application, are not considered as oxidic support materials. The polymerization catalysts used in the process of the invention are heterogeneous catalysts which comprise, as catalytically active components, oxygen-containing compounds of one or more elements of the transition group V and / or VI of the Periodic Table of the Elements. The catalysts which can be used according to the invention can be subdivided into two types of catalyst. Catalysts of type (A) are unsupported catalysts, ie catalysts which are oxide compounds of one or more of the elements of the transition group V and / or VI of the Periodic Table of the Elements and which do not contain or almost they do not contain support materials. The catalysts of type (B) belong to the class of supported catalysts and contain, as catalytically active component (s) one or more oxidic compounds of one or more elements of the transition group V and / or VI of the Periodic Table of the Elements supported on an oxidic support material that is not a zirconium compound containing oxygen, these supported catalysts do not contain technically effective amounts of halogen. These catalytically active components are also known herein as promoters.

Advantageous catalysts of type (A) are the oxides of chromium, molybdenum, tungsten, vanadium, niobium or tantalum or mixtures of two or more of these oxides, in the form of powders or molded articles, such as extrudates, spheres, rings or spirals. . Preferred catalysts of type (A) are the oxides of chromium, molybdenum, tungsten or vanadium or mixtures of two or more of these oxides or mixtures of one or more of these oxides with niobium oxide (Nb2o5) or tantalum oxide (Ta205 ). Of the different oxides of different oxidation state than the transition elements of groups V and VI can form, preference is given to using chromium (IV) oxide (Cro2), chromium (III) oxide (Cr203), molybdenum oxide (VI) (Mo03), tungsten oxide (VI) (Wo3) / vanadium pentoxide (V205), niobium pentoxide (Nb20s) and tantalum pentoxide (Ta205) as catalysts for the process of the invention. These oxides can be prepared in a conventional manner, by calcination, in an oxygen-containing atmosphere, of, for example, ammonium chromate ((NH) 2Cr04), ammonium molybdate ((NLH) 2Mo04), ammonium tungstate (( 4) 2 04), ammonium vanadate ((NH4VO3), ammonium niobate ((NH4Nb03) or ammonium tantalate (NH4Ta03) As a result of this method of preparation, the oxides thus obtained may also contain small amounts of oxides of lower or possibly higher oxidation states of these elements.

The oxidic support materials for catalysts of type (B) are the heat-resistant, solid oxides of the elements of the main groups II, III and IV of the Periodic Table of the Elements and of the elements of the transition groups I, II, III and IV (excluding zirconium), VII and VIII, the elements of transition group III including rare earth metals. As will be described in more detail herein, these oxides may be present in the support material, as a result of their preparation, in the form of defined oxides of stoichiometric composition, in the form of non-stoichiometric oxidic compounds, in the form of combined valence oxides, or, when using a support material containing a plurality of elements of the aforementioned groups of the Periodic Table of the Elements, in the form of mixed oxides of the relevant elements, in which case, again as As a result of the preparation method, the support in question can contain individual types of these oxide forms almost exclusively, but also different forms of use simultaneously. For the purpose of the present application, the heat-resistant oxides are those of the aforementioned oxide forms which are formed under the individual calcining conditions used for the preparation of the individual catalysts or are stable under these conditions. Of the oxides of the main group II of the Periodic Table of the Elements, for example, preference is given to the use of the beryllium, magnesium and calcium oxides as support material. The preferred support materials of the main group III are boron oxides, aluminum gallium. The suitable support materials of the main group IV are the silicon, germanium, tin and lead oxides, with silicon oxides (SiO2), tin and lead being preferred, the preferred support materials of the different tin and lead oxides being in particular tin dioxide (Sn02), lead (II) oxide (PbO), lead dioxide (Pb02) and minium (Pb304). It is also possible to use the oxides of the elements of transition group I of the Periodic Table of the Elements as support materials for the catalysts that can be used according to the invention, but preference is given to copper oxides and , in particular, copper (II) oxide (CuO). The preferred oxidic support material of transition group II of the Periodic Table of the Elements is zinc oxide (ZnO). The suitable oxides of the transition group IV of the Periodic Table of the Elements for use as support materials are titanium dioxide (Ti02) and hafnium dioxide (Hf02)., giving preference to titanium dioxide. Of the transition oxides of group VII of the Periodic Table of the Elements, the manganese oxides are preferably used as a support material, particularly preferably manganese dioxide (Mn02) and manganese oxide (III) (Mn203), and the preferred support materials of the oxides of the elements of transition group VIII are the iron, nickel and cobalt oxides, in particular the iron oxides Fe203 and Fe304. All the oxides of the elements of the transition group III of the Periodic Table of the Elements including the rare earth metals can be advantageously used as support material for the catalysts which can be used according to the invention, giving preference to the oxide of scandium (Sc203), yttrium oxide (Y203), lanthanum oxide (La203), cerium (III) oxide (Ce203), samarium oxide (III) (Sm203) and ytterbium oxide (Yb203). Particularly preferred support materials of the catalysts used according to the invention are boron trioxides, aluminum oxides, lanthanum oxides, titanium oxides, silicon dioxides, lead oxides and iron oxides including their various crystal modifications, in particular iron (III) oxide (Fe203) and Si02. It is also advantageous to use the mixture of two or more of these oxidic support materials as support for the catalysts used according to the invention. Catalysts with support for use in accordance with the invention can be made in various ways by conventional methods, for example by impregnation of support material with a solution, preferably with an aqueous solution, of a precursor compound by the promoter (s). ) pertinent, wherein, in the case of doping the support with a plurality of promoters, these promoters can be applied to the support material simultaneously or in an impregnation step or individually, successively in a plurality of impregnation steps, by coprecipitation of the precursor compounds by the support material and the promoter by cosolvation, that is, by simultaneous dissolution of this precursor compound in a solvent, preferably water, and evaporation of the resulting solution, followed by drying and calcination of the resulting solids to give the catalysts that can be used according to the invention. When the catalysts are prepared by impregnation, none of the prefabricated support materials, ie the relevant oxide or a mixture of a plurality of suitable oxides, or a precursor compound for the support material that is sparingly soluble in the relevant solvent and can be converted into the support material by heat treatment, for example a hydroxide, a carbonate, a nitrate or an organic salt of the support component, is impregnated with a solution, preferably an aqueous solution, of a precursor compound for the promoter ( is) relevant to, in general, from 20 to 80 ° C, the impregnated support material or precursor compound for the support material is dried and the impregnated and dried support material, or its precursor compound, is then calcined at the temperatures at which the precursor compound of the promoter and, optionally, the precursor compound for the support material, is / are used, decomposed to give the promoter catalytically active or the oxidic support material, respectively, and the finished catalyst is formed. When the catalysts of the invention are prepared by precipitation of precursor compounds for the support material and / or of the promoter, a conventional precipitation method can be used. This generally involves the precipitation of solutions of water soluble salts of the support component and / or of the promoter by the addition of a precipitating agent. Examples of precipitating agents used are bases such as alkali metal hydroxides and carbonates or aqueous solutions of ammonia., which form sparingly soluble compounds with the relevant salts of the support component. The preferred precipitating agents are alkali metal carbonates. The choice of the base depends on the elements of the support component that will be precipitated in each particular case. Depending on the type of the support component to be precipitated, it may be necessary to carry out precipitation under a pH control in a certain pH range, since some of the elements suitable as a support component have amphoteric properties and / or can form complex compounds soluble with the precipitating agent. It should be appreciated that, depending on the type of the support component or precursor compound of the promoter to be precipitated, it is also possible to use other precipitating agents such as the aforementioned bases, if the anions of these precipitating agents can form sparingly soluble compounds with the relevant elements of the support component or promoter precursor compound. For example, it is possible to use solutions of water soluble salts of support component elements, for example, alkali metal silicates such as soluble glass or alkali metal borates, such as borax, for the precipitation of the relevant promoter precursor compound, being it is generally advantageous to carry out such precipitation in a certain pH range. The resulting precipitates are advantageously separated from the liquid, washed until they are free of salt, dried and calcined. It may also be advantageous to precipitate only the support component by one of the aforementioned methods in a precipitation reaction and to mix the resulting precursor for the support material, for example, with an oxide or a precursor compound for the promoter, followed by drying and subsequent calcination to produce the catalyst. It is also possible to precipitate the precursor compound of the promoter on the support material initially loaded in the precipitation vessel, followed by working the resulting material as described above to produce the catalyst. It is particularly advantageous to precipitate the precursor compounds for the support material and the promoter in separate precipitations, followed by mixing the resulting precipitates, for example, in a kneader or extruder, and conversion to the catalyst in a similar manner. Instead of the precipitation of the catalysts to be used according to the invention, these can also be produced by cosolvation of the precursor compounds for the support material and the promoter, evaporating this solution and drying and calcining the resulting residue. In addition to the wet chemical methods described above, the promoter precursor compounds can be deposited on the support material or a precursor compound for the support material, for example, by vapor deposition of the promoter elements or promoter element compounds or by atomization to the flame. Calcination in an oxygen-containing atmosphere then gives the catalysts used according to the invention. The catalyst precursors obtained by impregnation, precipitation or cosolvation are generally dried at from 50 ° C to 300 ° C, preferably from 60 ° C to 200 ° C, particularly preferably from 70 ° C to 150 ° C. To dry under reduced pressure it is possible to accelerate the drying process or use a drying temperature lower than the established values. The dried catalyst precursors or the catalyst precursors obtained by vapor deposition or flame atomization are generally calcined in an oxidizing atmosphere, in particular in the presence of oxygen-containing gases, preferably in air. The calcination temperature is generally greater than 300 ° C to 1000 ° C, preferably greater than 300 ° C to 800 ° C, particularly preferably greater than 300 ° C to 700 ° C. Depending on the type, the method of preparation and the composition of the relevant catalyst precursor, the calcination time is generally from 1 to 20 hours. During calcination in an oxidizing atmosphere, the dry catalyst precursors obtained by the preparation method used in the particular case (impregnation, precipitation, cosolvation, vapor deposition or flame atomization) are converted into the catalysts, the precursor compounds for the support material and / or the promoter contained therein being thermally decomposed or oxidized to the corresponding oxidic compounds. Examples of the precursor compounds are salts that can be decomposed thermally or oxidatively, when the impregnation method is used; when the precipitation method is used, hydroxides, carbonates, basic salts, oxyhydroxides, silicates or poorly soluble borates; and the relevant oxidizable elements when using the vapor deposition methods or the flame atomization method. Depending on the type, composition and method of preparation of the catalyst precursor, the conditions of the calcination used give rise to the decomposition of the salts which can be thermally or oxidatively decomposed, for example, to give the pertinent oxides, the combined valence oxides and / o the mixed oxides, at a conversion of the precipitates obtained by precipitation and subsequent drying, for example in the pertinent oxidic or non-stoichiometric oxidic compounds, oxides of combined valence and / or mixed oxides, and to the oxidation of the elements deposited in the support material or a precursor of the support material by vapor deposition to give the corresponding oxides. Consecutive reactions may also occur in the case of calcination. These involve, for example, the reaction of the initially formed oxides of the promoter precursor with the oxidic support material in a solid phase reaction to give the mixed oxides or the conversion of relatively high oxidation state promoting compounds or the components of the support on the surface of the catalyst with relatively low oxidation states of the promoter or support components present within the catalyst particle in a solid phase reaction to give combined or non-stoichiometric valence oxides. Accordingly, depending on the type and composition of the support and the components of the promoter and its precursors, the method of preparation of the catalyst precursor and the calcining conditions used, the individual types of the oxide forms described above may predominate over the other forms of oxide in the finished catalyst, or various types of these oxide forms may be present simultaneously. Therefore, it will be appreciated that the calcining conditions for each individual catalyst should be chosen according to their composition, the manner in which the promoter elements have been deposited on the support material or its precursor and the type of the compounds of the promoter elements used for this purpose, if optimum results are to be achieved in the process according to the invention. The individual choice of these calcination conditions within the range of the aforementioned calcination temperatures and the calcination time can easily be done by a person skilled in the art by means of some routine experiments. The preparation methods described above for the catalysts are only illustrative and may vary, if desired. Which of the above-mentioned methods for preparing the catalysts for type (B) is used, is generally not critical to the effectiveness of these catalysts in the process according to the invention. The choice of a particular preparation method generally depends on the availability of particular starting materials for the relevant promoters and support materials, the availability of the equipment required for the methods of operation, the composition of the desired catalysts and the known chemical behavior in the texts of the starting materials available for the preparation of the relevant catalysts under the conditions of the different preparation methods. In addition to its elemental composition, the exact chemical structure of the catalysts used according to the invention is almost unknown for the reasons mentioned above. It is possible that the elements of the promoter of the transition group V and / or VI of the Periodic Table of the Elements and the oxidic support material form mixtures of oxides or oxides of combined valence that form catalytically active centers and thus catalyze the polymerization of isobutene, but it is also possible that the elements of the promoter are bound on the surface of the support material by chemical bonds, for example by oxygen bonds, and in this way cause the catalytic activity of the impurified support materials that have almost no catalytic activity in them. the process according to the invention without the doping. Therefore, it is impossible to specify the mode of action of these catalysts: when the acidity of the catalysts that can be used according to the invention is determined by Ham ett titration, some prove to be strongly acidic using this titration method, while others They are almost neutral but still catalyze the polymerization of isobutene giving rise to the high content of terminal double bonds. Since the exact chemical structure of the catalysts used according to the invention is unknown, the individual catalysts are characterized by their support element and content of promoter element in percent by weight, calculated as the relevant support element or promoter element, respectively, based on the total weight of the calcined catalyst. The remainder of 100% by weight is mainly contributed by the oxygen bound to these elements, but also impurities and technically ineffective, for example, alkali metal compounds, which have been incorporated into the catalyst in the course of its preparation. The catalysts which are used according to the invention can also contain, after their calcination, hydrogen in chemically bound form, for example, in the form of OH groups or in the form of water of crystallization which can not be removed even under the conditions of calcination. The molar ratio of the support element (s), calculated as the shape of the relevant support elements, to the promoter element present in the catalyst or, the cumulative promoter elements present in the catalyst, in each case calculated as the element corresponding, support element / promoter element is generally from 50:50 to 99.9: 0.1, preferably from 54:46 to 99.7: 0.3, particularly preferably from 80:20 to 98: 2. The alkali metals, which are usually present in the catalyst in the form of oxygen-containing alkali metal compounds, can be present in the catalyst as a result of their preparation in amounts of up to 1% by weight, for example, from 0.1 to 1.0%. by weight, in each case calculated as alkali metal. The alkali metals can be introduced into the catalyst, for example, by the use of precipitating agents containing alkali metal or by alkali metal impurity or constituents of the promoter element compounds used for the promotion or precursor compounds used to prepare the support material. The polymerization catalysts, used according to the invention, are generally and preferably halogen-free. However, depending on the manner of their preparation, in particular depending on the halogen content of the raw materials used for their preparation, these catalysts can be contaminated with halogen in quantities that are technically and inevitably introduced by these raw materials, but are technically inefficient and does not show a promoter effect nor lead to the formation of halogenated polyisobutene. The reason for the technical inefficiency of such unwanted, halogenated impurities in the catalysts used according to the invention is that these impurities are distributed unspecifically throughout the catalyst and are not part of the catalytically active centers. This is the difference between the catalysts used according to the invention and, among others, the halogen-containing catalysts according to US-A 4 288 649 or US Pat. No. 5,326,920, in which the halogens are catalytically incorporated into the centers active catalysts in a controlled manner. The catalysts used according to the invention contain technically unavoidable halogen impurities in an amount, generally, less than 1000 ppm by weight, preferably less than 100 ppm of halogen by weight, in each case based on the total weight of the calcined catalyst, giving particular preference to the use of halogen-free catalysts. Some of the catalysts used according to the invention are known, for example, some chromium or silicon dioxide catalysts described in EP-A 535 516 which to date have only been used in processes for the polymerization of ethylene. Before use in the process according to the invention, the catalysts to be used according to the invention are advantageously packaged, that is, they are modeled to give patterned articles such as tablets, spheres, cylinders, rings or spirals or crushed into chips. in a conventional manner and preferably used in this form in a fixed bed in the reactor or crushed to a powder and used in this form, advantageously as suspension catalysts. The catalysts used according to the invention can be stored for an almost unlimited time, in particular with the exclusion of moisture. The catalysts that have been wetted are advantageously used under atmospheric pressure or reduced pressure, under atmospheric pressure in general at temperatures above 150 ° C, preferably at 180 to 300 ° C under reduced pressure also at low temperatures, before use. The starting materials that can be used in the process of the invention are two isobutene sites and pure hydrocarbon mixtures comprising isobutene, such as C4 refining or isobutane / isobutene mixtures from the dehydrogenation of isobutane. The refine C4 refers to mixtures of hydrocarbons obtained by substantial separation of 1,3-butadiene, i.e. separation to trace amounts, for example by extractive distillation, from the C4 fraction of steam thermofractioners or mobile bed catalytic fractionation ( see Weissermel, Arpe: Industrielle Organische Chemie, pp. 69, 102-103, 2nd Ed., Verlag Chemie 1978). The process of the invention can be carried out batchwise or continuously to, in general, from -30 ° C to + 40 ° C, preferably from -20 to + 30 ° C, particularly preferably from -50 ° C to +20 ° C, under atmospheric pressure or superatmospheric pressure, especially under the autogenous pressure of the reaction system, so that the isobutene remains in liquid form. It is possible to use conventional reactors such as reactors with agitator or cycle reactors in batch operations of the process or cycle reactors or reactors in battery in continuous operations of the process. Also advantageous is the use, in continuous operations of the processes of the invention, tubular reactors or tubular reactors in batteries operated in upflow or downflow mode. It is possible for the catalysts used according to the invention, preferably when using reactors with tubular cycle or reactors, which are adaptable in a fixed bed or suspended in the reaction medium in powder form. The polymerization of isobutene can be carried out with or without a halogen-free solvent, preferably apolar, preferably hydrocarbons. When mixtures of hydrocarbons containing isobutene are used as starting materials, the hydrocarbons present in addition to isobutene act as solvents or diluents. Due to the exothermic nature of the polymerization of isobutene, it may be advantageous to provide the reactors used with internal or external cooling medium. The desired average molecular weight M n of the polyisobutene can be adjusted by varying the reaction parameters in the process of the invention. In the batch process, the average molecular weight Mn is generally adjusted by varying the amount of catalyst used, the reaction time and the reaction temperature. Depending on the amount of catalyst used, the reaction time is generally from 0.01 to 10 hours, preferably from 0.1 to 8 hours. In the discontinuous mode of the process of the invention, the catalyst is generally added in an amount of 0.1-50% by weight, preferably 0.5-20% by weight, particularly preferably 1-10% by weight, in each case based on in the weight of isobutene present in the starting material used. Depending on the catalyst and starting material used, the optimum polymerization conditions for the preparation of polyisobutene with a desired average molecular weight Mn is advantageously determined in preliminary experiments. In continuous operations of the process of the invention, the average molecular weight Mn is adjusted accordingly, but here the reaction parameters of the space velocity and residence time vary in place of the amount of catalyst used. The separation of the polyisobutene from the polymerization mixture generally does not include any special technical characteristics and can be effected by distillation, which, when a suspension catalyst is used, is preceded by the removal of the suspended catalyst, by filtration, centrifugation or decantation. The distillation advantageously initially separates the volatile components of the polyisobutene from the polymerization mixture, such as unconverted isobutene, hydrocarbons present in the starting materials or added as solvents and their high-boiling sub-products, for example, weight isobutene oligomers low molecular The process of the invention provides an inexpensive way to prepare halogen-free polyisobutene, reagent having an average molecular weight Mn of generally 280-10000 dalton, preferably 400-6000 dalton, particularly preferably 500-5000 dalton, and a content of double terminal links of more than 50% mol.

Examples I. Catalyst preparation AL catalysts were prepared and used in powder form The contents of Mo, W, Si, Pb, La, Fe, and V of each catalyst were determined by X-ray fluorescence analysis (Lit. R. Boc: Methoden der Analytischen Chemie; Vol.2: Nachewis-a Bestimmungsmethoden Teile 1, Verlag Chemiee, Weinheim 1980), the contents of B, Cr, and Ti of each catalyst were determined by ICP (Inductively Coupled Plasma, Inductively Coupled Plasma) -atomic induction spectroscopy in Analytical Atomic Spectrometry; 2nd Ed., VCH Verlagsgesellscheaft, Win eim), the contents of Cl and S of each catalyst were determined by the Schoniger method and by combustion analysis (Lit .: F. Ehrenberger, Quantitative organische Elementaranalyse, VCH Verlagsgesellschaft, Weinheim 1991). Before the analysis of these elements, the calcined catalysts were again dried until a constant weight was obtained and immediately analyzed in this way. Catalyst A: 50 g of ammonium heptamolybdate tetrahydrate ((NH4) 6M? 7? 2 - 4H20) was calcined in air at 500 ° C for 5 h. After calcination, the catalyst had a Mo content of 66.0% by weight. Catalyst B: 50 g of Si02 (Aerosil® 200 from Degusa, Hanau) were placed in a 1 1 flask and mixed with a solution consisting of 51.42 g of heptamolybdate ammonium tetrahydrate ((NH) 6Mo7024, 4H20) and 700 ml of water. The suspension was rotated in a rotary evaporator for 30 min. The excess water was removed at 60 ° C. The resulting material was pre-dried at 150 ° C for 16 h and calcined in air at 500 ° C for 16 h. After calcination, the catalyst had the following contents of Mo and Si: Mo: 26.0% in that Si: 28.5% by weight Catalyst C: A mixture of 39 g of (NH) 6Mo7024"4H20 in 100 g of water and 142 g of FeOOH were kneaded for 90 min and then dried at 120 ° C for 12 h.The material was then sieved and then calcined 500 ° C for 2 h After calcination, the catalyst had the following contents of Mo and Fe: Mo: 13.6% by weight Fe: 54.0% by weight Catalyst D: 50 g of Pb (N03) 2 were placed in a 1 1 flask and mixed with a solution consisting of 37.31 g of (NH4) 6Mo7024 * 4H20 and 250 ml of water. The suspension was rotated in a rotary evaporator for 30 min. The excess water was removed at 60 ° C. The resulting material was pre-dried at 150 ° C for 16 h and calcined in air at 500 ° C for 16 h. After calcination the catalyst had the following contents of Mo and Pb: Mo: 31.5% by weight Pb: 49.0% by weight Catalyst E: 88.3 g of a (N03) 3'6H20 were placed in a 1 1 flask and mixed with a solution consisting of 12.6 g of (NH4) 6Mo7024 • 4H20 and 400 ml of water. The suspension was rotated in a rotary evaporator for 30 min. The excess water was removed at 60 ° C. The resulting material was pre-dried at 150 ° C for 16 h and calcined in air at 500 ° C for 16 h. After calcination, the catalyst had the following contents of Mo and La: Mo: 17.7% by weight La: 47.5% by weight Catalyst F: 50 g of boric acid were placed in a 1 1 flask and mixed with a solution consisting of 199.8 g of heptamolybdate ammonium tetrahydrate ((NH4) 6Mo7? 2 'H20) and 600 ml of water. The suspension was rotated in a rotary evaporator for 30 min. The material was then pre-dried and calcined in air at 500 ° C for 16 h. After calcination, the catalyst had the following content of Mo and B: Mo: 55.0% by weight B: 4.1% by weight Catalyst G: 50 g of iron (II) sulphate heptahydrate were placed in a 1 1 flask and placed with a solution consisting of 2.83 g of VC13 and 250 ml of water. The solution was rotated in a rotary evaporator for 30 min.

The excess water was removed at 60 ° C. The resulting material was pre-dried at 150 ° C for 16 h and calcined in air at 500 ° C for 16 h. After calcination, the catalyst had the following Fe content, V, Cl and S: Fe: 29.8% in peos V: 5.4% in weight Cl: 0.001% in weight S: 16.0% in weight Catalyst H: a mixture of 20 g of tungstic acid (H2W04) in 80 g of a NH3 solution of 32% concentration were kneaded together with 84 g of FeOOH for 90 min, and then dried at 120 ° C for 12 h. The material was crushed and calcined at 300 ° C for 2 h. After calcination, the catalyst had the following content of W and Fe: W: 15.5% by weight Fe: 56.0% by weight Catalyst I: 150 g of titanium dioxide were mixed together with 37.5 g of Cr02 in 160 g of water for 120 min, and then dried at 120 ° C for 12 h. The material was crushed and then calcined first at 350 ° C for 2 h and then at 650 ° C for 2 h. After calcination the catalyst had the following content of Cr and Ti: Cr: 13.2% by weight Ti: 46.0% by weight Catalyst J: 120 g of Ti (OH) 4 were homogenized together with 16.8 g of olbic acid H2Mo04 and 100 ml of water in a kneader, dried at 100 ° C and calcined in air at 500 ° C for 5 h.

After calcination, the catalyst contained: o: 10. 0% by weight Ti: 51. 0% by weight Catalyst K: 120 g of Ti (OH) 4 were homogenized together with 15.3 g of H2W04 and 100 ml of water in a kneader, dried at 110 ° C and calcined in air at 700 ° C for 5 h. After calcination, the catalyst contained. W: 12.0% by weight Ti: 51.0% by weight Catalyst L: 120 g of Ti (0H) were homogenized together with 94.1 g of aqueous solution of vanadium oxalate (V content: 5 mol% calculated as V205) and 20 ml of water in a kneader, dried at 110 ° C and calcined at 500 ° C for 5 h. After calcination, the catalyst had the following contents of Ti and V: Ti: 52.0% by weight V: 7.7% by weight II. Polymerization of Isobutene The numerical average molecular weight Mn which is also known herein as the average molecular weight Mn was determined by gel permeation chromatography (GPC) using standardized polyisobutenes for calibration. The number average molecular weight Mn was calculated from the GPC chromatograms obtained using the equation.

Mn = S d / S (d / Mi where c ± is the concentration of the individual polymer species in the resulting polymer mixture and M is the molecular weight of the individual polymer species i The molecular weight distribution, also called dispersity (D), was calculated from the ratio of the average molecular weight (Mw) and the numerical average molecular weight (Mn) using the equation.

D = Mw / Mn where the weight average molecular weight Mw was determined from the GPC chromatograms obtained using the equation: Mw = S d Mi / S C the contents of a- and ß-olefins (formula I and II) were determined by NMR-13C spectroscopy.

In the 13 C-NMR spectrum, the C atoms of the terminal double bonds of the α-olefins I show peaks at a chemical shift of 114.4 ppm (CH2), and 143.6 ppm (C), while the signals of the C atoms of the Trisubstituted double bond of the β-olefins II are at 127.9 (= CH-R) and 135.4 ppm (= C (CH3) 2). The contents of a- and ß-olefins can be determined by evaluation of the peak areas and by comparison with the peak areas of other olefinic atoms. Deuterated chloroform (CDC13) was used as solvent and tetramethylsilane as an internal standard.

Example 1 10 g of isobutene were condensed in a 25 ml glass pressure vessel under argon at -70 ° C. 1 g of catalyst A that was pre-dried at 180 ° C / 0.3 mbar was added, the vessel was sealed and the suspension was stirred at 0 ° C for 2 h under the autogenous pressure of the reaction system. The polymerization mixture was then diluted with 10 g of n-hexane at 0 ° C. The unconverted isobutene was evaporated at room temperature, the catalyst was filtered and the added solvent was separated from the filtrate by distillation at room temperature, slowly reducing the pressure to 0.3 mbar. The low molecular weight isobutene oligomers were separated from the resulting polyisobutene by Kugelrohr distillation at 120 ° C / 0.3 mbar. The colorless polyisobutene that was obtained in a yield of 11% had an average molecular weight Mn of 3640 dalton, a molecular weight distribution D of 3.4 and a content of terminal double bonds (= α-olefin content) of 75 mol% . The ß-olefin content was 26 mol%.

Examples 2 to 12 Examples 2 to 12 were carried out as described in example 1. Table I summarizes the results of these batch processes obtained using the different catalysts and different amounts of catalysts.

Table 1: Polymerization by batch of isobutene Polymerization conditions: polymerization temperature: 0 ° C; autogenous pressure; polymerization time 2h; Amount used: 10 g of isobutene.

Ahem. catalyzes cant of Rendi- S (ID S n D N odor catalytic1) (I + II) 3) dor [g] [%] [% mol] [% mol] 2 B 0.6 13 76 86 2231 3.6 3 C 2.0 8 74 87 447 1.3 4 D 1.0 18 73 94 4246 2.2 E 1.0 3 65 85 5110 8.4 6 F 1.0 10 56 82 5294 2.5 7 G 1.4 5 78 91 1073 1.6 8 H 1.0 14 67 80 450 3.9 9 I 1.5 5 51 76 706 6.1 J 0.2 12 73 80 625 2.5 11 K 0.2 13 78 86 884 5.7 12 L 0.5 8 83 90 1126 4.6 1; Evaporation residue after Kugelrohr distillation (120 ° C / 0.3 mbar), based on the isobutene used. 2) S (I) = Content of terminal double bonds = α-olefin content 3) S (I + II) = Content of terminal double bonds + content of β-olefinic double bonds.

Claims (1)

1. REI INDICATIONS A process for the preparation of reactive polyisobutene, free of halogen, with a content of terminal double bonds of more than 50 mol% and an average molecular weight Mn of 280-1000 dalton, by cationic polymerization in liquid phase of isobutene or mixtures of hydrocarbons containing isobutene, which comprises polymerization at -30 ° C to + 40 ° C in the presence of a heterogeneous polymerization catalyst containing one or more oxide of the elements of transition group V and VI of the Periodic Table of the Elements or in the presence of a heterogeneous polymerization catalyst containing one or more oxidic compounds of one or more elements of the transition groups V and VI of the Periodic Table of the Elements supported on a non-zeolitic oxidic support material which is not a compound of zirconium containing oxygen, the catalyst does not contain a technically effective amount of halogen. The process, as mentioned in claim 1, wherein the used catalyst contains, as the non-zeolitic oxidic support material, one or more oxidic compounds selected from the group consisting of the elements of the main groups II III and IV of the Table Periodic of the Elements and / or transitional groups I, II, III, IV, VII and VIII of the Periodic Table of the Elements. The process, as mentioned in claim 1 or 2, wherein the catalyst used comprises one or more oxidic compounds of vanadium, chromium, molybdenum or tungsten. The process, as mentioned in any of claims 1 to 3, wherein the catalyst used comprises, as a support material, one or more oxidic compounds of boron, aluminum, silicon, lead or lanthanum. The process, as mentioned in claim 4, wherein the catalyst used comprises, as a support material, one more boron, aluminum, silicon, lead, iron, titanium or lanthanum oxides.