DE947967C - Process for olefin polymerization with boron fluoride-phosphoric acid catalysts - Google Patents

Description

Process for olefin polymerization with boron fluoride-phosphoric acid catalysts It is known, coordination compounds of boron trifluoride with acids of phosphorus to use as catalysts for various conversions, especially for the Polymerization of olefins.

These catalysts were made by adding an acid of phosphorus treated with boron trifluoride at temperatures of about 27 to I2IO until the desired complex had formed, whereupon the resulting viscous liquid used as a catalyst.

Catalysts produced in this way, however, have various disadvantages. They have poor storage stability and decompose if left to stand even at ordinary temperature with the formation of an acid gas and a precipitating gas Solid. This decomposition reduces the activity of the catalyst, and it forms a highly corrosive substance, which the usual packaging vessels attacks. Furthermore, these catalysts have a relative ratio in different conversions short lifespan; in addition, they are not very suitable for a steady mode of operation. At high reaction temperatures z. B. the catalytic activity decreases rapidly, and when the catalyst is on a solid is deposited, the catalyst bed will soon be contaminated by deposits and clogged in the end.

According to the present invention, a better catalyst is obtained if you mix an acid of phosphorus with boron trifluoride at a temperature below + 100, advantageously below + 4 "connects.

The liquid complex produced in this way is stable and can last for a long time can also be stored at elevated temperatures without decomposing or degrading will. It -suitable for steadily conducted catalytic processes, in particular on a solid support and even at relatively high temperatures.

The coordination compounds produced at low temperature have a somewhat different composition than the previously known compounds of this type. It appears that the compounds formed at low temperatures have the following typical structure: Compounds, on the other hand, which are produced at higher temperatures, are subject to a gradual dissociation during their production and storage and appear to liberate hydrogen fluoride until finally boron phosphate remains. In addition to the coordination compound, the complex produced at the higher temperatures appears to contain a mixture of degradation products.

The catalysts of the invention are quite acidic, and theirs relatively high acidity leads to catalysts for some reactions are overactive. According to another feature of the invention, the activity of the Modified the catalyst complex by adding an acid des in it as the free acid Mixing phosphorus. Such a product is particularly valuable when one wants to control the molecular weight of polymers produced by the polymerization of Olefins are produced.

According to a further feature of the invention, the catalyst complex used for conversion reactions in the presence of boron trifluoride coming from the outside is fed. This procedure in particular is of value to an excessively high level Suppress loss of BF3 from the complex and thereby the maximum catalytic Activity when working steadily or at relatively high temperatures to be maintained for a long time, since this results in an excess of boron trifluoride on the catalyst guaranteed over the amount necessary to form the coordination compound is. Such catalysts are used especially for reactions in which less reactive compounds are involved, e.g. B. in the polymerization of propylene.

According to a further feature of the present invention, the reaction zone, which contains the catalyst, in the course of the process externally liquid catalyst added. In the case of relatively less reactive compounds, there is a significant one Induction time necessary before the complex catalyst reaches its maximum activity achieved, even if one externally supplied boron trifluoride in the reaction zone maintains. The steady or intermittent addition of a small but effective one Amount of the liquid complex together with externally supplied boron trifluoride gas shortens the induction time and also ensures a constant high catalytic Activity. This procedure is used in processes in which the catalyst is used on a solid support.

It was further found that the catalyst complex, in particular if used on a solid support, pretreated with boron trifluoride can be so that you already have an excess of this compound before the Catalyst comes into contact with the olefin material to be polymerized. This pretreatment also effectively reduces the induction time, particularly during polymerization of propylene.

The coordination compounds used as catalysts according to the present invention can be obtained by making an acid of phosphorus at a temperature below about 100 treated with so much boron trifluoride (bs3) that a complex with the correct ratio of acid to BF3 is created.

In general, gaseous BF3 becomes the liquid acid of phosphorus added. One can also first create a complex of BF3 with an organic aliphatic Ether, e.g. B. Dimethyl ether, diethyl ether, ethyl propyl ether and the like. This liquid ether complex can then the acid of phosphorus at low temperature be added in the amount necessary for the formation of the coordination compound. The excess ether is then reduced by distillation under Pressure removed.

The temperature at which the acid of the phosphorus and the BF3 interact being united into the coordination compound is critical. In general, it is advisable to keep the reaction mixture below + 4 °, to keep unwanted side reactions to a minimum.

The reaction of the Bs3 with the acid is exothermic.

Therefore it should be ensured that the heat of formation is dissipated will. That is possible if you put the reactants in one with cooling coils equipped or a jacketed reaction zone combined and one Allows coolant to circulate through a coil or jacket.

If you use iooolic acids, the low reaction temperatures Difficulties arise due to crystallization phenomena. These can be avoided be done by z. B. adds some BFa at room temperature and then the Cools the mass to the desired temperature before adding the main part of the BFa. Many acids of phosphorus, however, can usually be doors below +4 to 100 are supercooled without crystallization difficulties appear.

The correct low temperature range for the complex to be formed depends to some extent on the viscosity of the reactants and the Reaction speed. The reaction temperature should be high enough so that the reaction proceeds at an acceptable rate and the substances remain liquid. Usually temperatures can be sustained as low as -70 or even lower will. The liquid complex thus obtained is generally at temperatures up to to - I8 "or even below liquid. After the formation of the complex has ended it can be used immediately as a catalyst, but you can also use it heat to ordinary temperature and store.

Acids of phosphorus can be used for the production of the coordination compounds Orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, hypophosphorous acid, phosphorous Acid, metaphosphorous acid, and various other acids of phosphorus, are beneficial Phosphoric acids themselves can be used.

The acid in question can consist of a single acid or of a Mixture of different acids exist.

Even if the acids are used advantageously in 100% form, they can also contain some water. For example, one can use phosphoric acid hemihydrate or use syrupy 850% phosphoric acid from the trade. It is in general undesirable to use large amounts of water, which boron trifluoride in side reactions consume.

In some cases, however, the water forms a complex in the acid with the BF3 as well as oxyfluoboric acids, which are not to be regarded as harmful. Usually BF3 is used in amounts such that a complex with essentially equimolar amounts of acid and BF3 are produced, although in some cases a ratio from 1 mole of phosphoric acid to 2 moles of BF3 or higher is applied.

Examples of typical coordination compounds are H3PO4.BF3, BF ,, HPO3.BF3, H4P2O7BFg, H4P2O 2 BF3 and the like.

The acid component of the complex can be modified by a metal is incorporated into it or the mixture. So can metal salts of free acids of phosphorus, e.g. B. salts of Cu, Fe, Ni, U, Zn, Co, Mn, Ag, Cd and Cr, in the Preparation of the complex used or added to it. The mixture can also contain small amounts of metal oxides, sulfates and the like, e.g. B. those of Titanium, zirconium, thorium, vanadium, etc.

The coordination compound can also be added by adding varying amounts modified by boric anhydride, e.g. B. about 1 to 20% of the complex. So can at least some of the escaping from the catalyst during its use Hydrogen fluoride react with boric anhydride to regenerate BF3, which in turn recombine with free acid to regress the complex can. This is a useful way of extending the life of the catalyst represent.

If you want to produce a catalyst, the free acid des Contains phosphorus, one need only add the free acid to the complex, which is after is prepared by the process described above in the desired molar ratio. This addition can be at the reaction temperatures used for the formation of the complex or at higher temperatures. Any suitable acid of phosphorus can be used use. If the free acid is to be the same as it is as an acid component of the complex is used, the product is simply prepared by in one step insufficient amounts of BF3 are added to the acid (below 100). Through this you can use a mixture of free acid and complex in any ratio produce. In general, it is desirable to form mixtures in which the molar ratio from coordination compound to free acid of phosphorus in the range of about I. : 9 to 9: I lies. This mixture is generally a viscous liquid, which has many properties of the coordination compound.

The complexes described above can be used in liquid form as catalysts be used.

For example, the item in question can be handled by the Conduct catalyst containing container. Preferably, however, one uses the Complex on a granular or finely divided solid. A catalyst film can be formed by placing a thin film of the complex on non-porous, inert solid particles such as pieces of quartz, pumice stone, copper shavings, sand and the like and this material with the olefin or other feedstock under appropriate conditions brings in contact.

According to a preferred embodiment of the present invention the liquid complex is deposited on a solid adsorbent support.

In this way one gains a solid catalyst, which is continuously carried out Process in a manner known per se in the form of a quiescent bed, a suspension or a fluidized bed and the like.

When preparing such a solid catalyst, the above-described one is used Coordination compound mixed in the ratio with finely divided porous solid, which is the concentration of the complex required for the application in question on the catalyst results. Different adsorbent solids can be used, z. B. Activated charcoal of various origins, silica and containing aluminum silicate Substances such as silica gel, kieselguhr, fuller's earth, clays such as bentonite, and others Diatomaceous earth. The active coordination compound content of the finished solid catalyst can be between about 5 percent by weight of the total catalyst up to 50 to 75,010 due to the active catalyst component. The solid material can be used for the necessary grain size are brought to the respective intended use. So are grain sizes generally suitable for use in quiescent bulk, while when using the Catalyst in the form of a suspension or as a fluidized bed smaller particles, z. B. in the range of 0.246 to 0.147 mm, or even finer, can be used can.

It is generally only necessary to use the solid adsorbent and mixing the liquid complex in the desired ratio until the adsorbent completely absorbs the liquid complex. The finished supported catalyst is dry, flows freely and generally does not require subsequent drying and calcining at elevated temperatures. The addition of the liquid is facilitated by the adsorbent is first subjected to reduced pressure and then it is subjected to the liquid Complex mixed under reduced pressure.

The catalysts of the present invention find particular in the polymerization of olefins, e.g. B. the production of additives for Motor fuel, from chemical intermediates, etc., from low molecular weight olefin hydrocarbons Use. As a starting olefin z.

Propylene, butylenes, pentenes and their mixtures.

Ethylene is generally subject to the conditions used very little reaction but can be included as part of the olefin feed to be available. The catalyst can also be used with higher molecular weight mono-olefins be e.g. B. the heptenes, octenes, styrene, inden and the like Polymerization of diolefins can be used, such as butadiene, isoprene and others unsaturated aliphatic hydrocarbons. The feed can be paraffinic Contain diluents, inert gaseous diluents such as nitrogen and the like. The olefin concentration in the feed can be about 200%, or less, up to 1000/0.

The reaction conditions of the olefin polymerization can be used in one further area. The reaction temperatures can range between temperatures about below room temperature up to about 260 °, although the catalyst is subject to faster decomposition at the higher temperatures. Preferred Temperature ranges are between about 21 and 1490. The pressures can be between Atmospheric pressure and 102 ast overpressure; the higher pressures are particular expedient to the decomposition of the catalyst at relatively high reaction temperatures to delay.

The olefin feed rate can be between about 0.1 and 10 parts by volume liquid / space part catalyst / hour. The chosen reaction conditions apparently depend on the type of olefin used, the relative catalyst activity and other conditions as known in the art.

When carrying out a polymerization process with a catalyst, which contains an excess of BF8, it is only necessary in the catalyst to maintain sufficient externally supplied BF5 in the reaction zone containing to suppress the deactivation of the catalyst complex and the complex in essential to keep fully saturated with BF3. Those fed to the reaction zone Amounts of BF3 are generally not of critical importance as long as the the above conditions are met.

The BF3 can run at a speed of about 0.1 to 30 or more, under the usual polymerization conditions, preferably about 1 to 20 parts by volume Gas / space part catalyst / hour are fed.

The BF3 to be fed to the reaction zone is expediently added to the olefin feed to, but it can also through a special or several special inlet openings feed to the reaction zone.

It is advisable to use funds to evenly distribute the BF3 to be provided at all points in the reaction zone. The BF3 is advantageously even added during the reaction, but in some cases it can also be added intermittently to add.

If a pretreatment of the catalyst is desired, either contains the liquid or solid complex, BE3 becomes in the absence of the olefin feed injected into the zone containing the catalyst. This BF3 supply must be sufficient take a long time so that the catalyst and support are saturated. The pre-treatment with gaseous BF5 at temperatures from about room temperature up to about I49 " or higher in amounts of about 1 to 30 parts by volume / part of space / hour. Treatment times from about 30 minutes to about 10 hours are generally sufficient to achieve the Reduce induction period of the catalyst and a catalyst of high To gain initial polymerization activity.

The supply of the liquid during the course of the polymerization Complex of BF3 and acid of phosphorus in the reaction zone is easily effected by passing the complex at the top of the reaction zone through a suitable distributor device introduces so that it mixes with the catalyst bed or flows over this or otherwise with the catalyst and its support during the polymerization comes into contact. As the complex catalyst in common hydrocarbons is essentially insoluble, it is not recommended to take it with the olefin feed to introduce. The amount of liquid complex added during the polymerization is quite low. Amounts in the range from about 0.01 to 1 volume part liquid / volume part Olefins / hour are generally sufficient, since the complex supplied is the complex to replace that as a result of the reaction with hydrocarbon or in some other way may have been removed from the zone.

The practice of the present invention is shown in The following examples are illustrated, but they are in no way exhaustive of the invention mark.

Example I H, production of the Katdlysatoren a) 100% H3 P 04. The Phosphoric acid required to produce this catalyst was obtained by phosphorus pentoxide is slowly added to 850% phosphoric acid with stirring (39.5 g P2 05/100 g 85 ° / 0 H3PO4). A three-necked round bottom flask is used for this, the with a mechanical stirrer, a reflux condenser, a calcium chloride tube and is equipped with a heating jacket. After the required amount of P206 has been added was would the mixture was stirred well and heated to about 80 ° for 4 hours. The resulting mixture was 1000/0 phosphoric acid. b) Part of this 100% HaPO4 was treated with gaseous BF3 (purity 98%) until the same molar proportions of acid and BF3 had reacted. The temperature of the Reactant was kept at 60 to 66 ° during the entire reaction time. The walls of the glass vessel were heavily etched, apparently as a result of the development from acidic gas, probably hydrogen fluoride. Part of the liquid complex was now in a glass vessel closed with a stopper at room temperature stored. Gas bubbles developed and formed during storage a noticeable vapor pressure in the vessel.

After several weeks a white precipitate had emerged from the liquid Phase eliminated. c) Some of the 100% produced according to regulation a) H3 PO4 was placed in a glass jar that was in an ice bath. the Acid was supercooled to 0 ° and remained liquid at this temperature.

Then gaseous BF3 was introduced into the acid until the same molar Proportions of acid and BF3 had reacted. The mixture was during the kept the entire reaction time at 0 °. The glass vessel was not etched, and one Development of HF could not be observed.

Part of the complex obtained (H3PO4. BF3) was in one with a stopper closed glass vessel stored at room temperature for about 3 months. No gas bubbles and no solid precipitate formed during storage. It During this time, only a negligible vapor pressure developed. There was no evidence of decomposition of the during the entire storage period Complex.

Example 2 Comparison of the catalytic activity of supported catalysts Using the complexes according to Example I, b) and c), supported catalysts manufactured. In each case, 70 g of the complex became slow under reduced pressure added to 200 cc of the usual granular activated carbon at room temperature. The complex was made by the activated charcoal forming a free-moving, dry-looking Mass rapidly adsorbed.

For the polymerization experiments, the supported catalysts were used as Resting pour used. A C3 to C4 feed of approximately 48010 olefins was made steady at atmospheric pressure, temperatures from 25 to 1000 at speeds from about 0.5 to 1 parts by volume of liquid / part by volume of catalyst / hour through the beds directed.

If the preparation that is obtained at a higher temperature Complex contained [Example 1, b)], at a reaction temperature of 25 ° and one Throughput rate of 0.5 volume parts liquid / volume part / hour has been tested, an olefin conversion of 95,010 was reached at the beginning. The catalytic However, activity then quickly decreased and the olefin conversion fell in 4 hours to 39%.

Heavy deposits formed on the catalyst.

These deposits are likely to be the products of the reaction the action of hydrocarbons on the catalyst complex. If you have the the same catalyst used at a reaction temperature of 1000, was the Initial olefin conversion 94%, but deposits pooled on the Catalyst came on very quickly and clogging occurred after 2 hours of operation the reaction chamber. This clogging occurred even at a high throughput rate of I parts by volume of liquid olefins / part by volume of catalyst / hour, the catalyst consisted of about 20,010 complex and 80,010 activated carbon.

If you worked with catalytic converters, that would turn out to be lower Temperature-produced complex [Example I, c)] and activated carbon passed, remained this relatively free of deposits, and the sinking of the catalytic Activity was less intense than in the previous experiments. If you have this catalyst for example at 1000 and a throughput rate of 0.5 parts by volume more fluid When using olefins / space part catalyst / hour, an initial olefin conversion was obtained of 99010. -After 4 hours the conversion was still almost 50% without any clogging occurred or the degree of conversion continued to be abs. The life of the catalysts was significantly higher than that of the catalyst made at higher temperature, even if the latter at a reaction temperature of only 25 ° was used.

Example 3 Evaluation of mixed catalysts from complex and free Acid of phosphorus proportions of the coordination compound according to Example I, c) were with 100% free phosphoric acid according to Example I, a), in molar ratios of I: I or

I: 3 mixed. These mixtures and the IOo% phosphoric acid as well the 100% liquid complex BF3 HaPO4 according to Example 1, c), were finely divided Activated carbon precipitated to supported catalysts by the method according to Example 2 to manufacture. The finished catalysts contained about 44 percent by weight catalytic active ingredient, which is deposited on about 56 percent by weight activated carbon was.

Polymerization experiments were carried out using these supported catalysts carried out with the arrangement of the catalyst in quiescent bed. In any case it was a substantially anhydrous C3 to C4 hydrocarbon feed of about 48% C3 to C4 olefins for 4 hours at 100 °, atmospheric pressure and a throughput rate of 0.5 parts by volume of liquid olefins / part by volume of catalyst / hour steadily through the Catalyst bed passed through. The reaction chamber was closed Temperature control steam jacketed; their length related to diameter as about 30: I. Each The attempt lasted 4 hours. The test results # are in the table below I stated.

Table I. Molar ratio of complex to H3PO4 0: 100 1: 1 3: 1 100: 0 Olefin Conversion, Beginning / Ending Mole Percent 30/20 49/35 92/42 99/46 average conversion mole percent (4-hour the try) . ................. ...... ........ 21 40 58 70 Polymer yield, percent by weight. ........ I4 24 41 58 Selectivity for liquid product, weight percent 62 66 7I 84 product Beginning of boiling, ° CC ... 96 96 99 96 End of boiling point, ° ° C .................. ..... I66 I93 204 238 Percentage by volume gasoline. . ............. .. 100 96 96 68 Bromine number of gasoline (lfloo g Br / g) .. I56 I50.7 I30.8 109 It can be seen that under the conditions chosen, solid phosphoric acid as a catalyst gave relatively poor yields of product and a high proportion of gasoline in the product. On the other hand, the coordination compound-on-carrier catalyst had superior activity but tended to produce higher molecular weight polymers.

The supported catalysts according to the invention, the free phosphoric acid retained their high catalytic activity and produced a higher one Yield of gasoline than expected from the yields obtained from the two Iooo / 0 components were achievable.

Example 4 Effect of B F3 Supply During Polymerization On Polymerization experiment with arrangement of the catalyst as a resting bed was with a complex supported catalyst made up of 37 weight percent of the low temperature obtained complex according to Example I, c), carried out on 63 0 / o activated carbon. By this catalyst bed was at atmospheric pressure and a reaction temperature of 1000 with a throughput rate of 0.5 volume parts liquid / volume part / hour passed a substantially anhydrous C3 hydrocarbon feed, the 95 Contained 0 / o propylene. Together with the propylene, 9.5 parts by volume were BF3 gas / part by volume Initiated catalyst / hour.

Table II reaction time I hrs. # 1.5 hrs. 1 2 hrs. # 2.5 hrs. Polymer yield, percent by weight 1 55 66 92 Boiling range of the polymer Initial boiling point, ° C .......................... .... - 74 105 89 End of boiling point, ° C. .......... .................. - 274 302 311 approximate product distribution by volume Cg ............ ............... - 12 3 6 C12 .............. .......... ............... - 42 22 14 C15 # ..................... .... - 46 55 48 C18 ...................... F .......... - 0 20 32 Bromine number of the distillate (1 / 100g Br / g) ... . - 91 84 82 It can be seen that an induction time in excess of 1 hour was necessary before any appreciable yield of polymeric product was achieved. After about 2 hours the polymer yield increased to 92% of the feed, which corresponds to essentially complete conversion of the olefin content of the feed.

Comparative tests with dry and moist propylene without feed of BF3 from the outside resulted in practically no polymerization after 3 hours.

Example 5 Effect of the addition of both catalyst complex and also of BF3 during the polymerization of propylene This experiment was under carried out the conditions according to Example 4, but with the proviso that the reaction temperatures were between 100 and 134 °. At the top of the reaction chamber it also became more fluid H3PO4. BF3 complex catalyst on the catalyst bed with a uniform Flow rate of 0.025 volume parts liquid / volume part / hour injected. The liquid complex was prepared according to Example I, c).

The results of this experiment are shown in the table below III compiled.

Table III reaction time I hours I 1.5 hours 1 2 hours # 2.5 hours Polymer yield, percent by weight ................. 46 97 81 91 Boiling range of the polymer Beginning of boiling, ° C ............... ....... 101 78 62 62 End of boiling point, ° C ... ................. ...... 250 280 280 310 approximate product distribution by volume C9 ............. ................ 17 II 10 13 C12 ...................................... 34 19 14 9 C15 ...................................... 33 42 38 23 C18 ...................................... 10 16 25 40 C18 + .............. .............. ............... 8 II I3 Bromine number of the distillate (l / loo g Br / g) .............. 85 75 70 60 The induction time required to achieve high polymer yields was considerably shorter than in the experiment according to Example 4, and noticeable yields of polymeric products were obtained during the first hour of operation.

Example 6 Effect of the pretreatment of the complex catalyst with BF3 In this experiment, part of the complex supported catalyst according to Example 4 placed in the reaction chamber and 5 hours at 1000 at a throughput rate of 9.5 parts of gas / part of volume / hour pretreated with BF3 gas to the carrier to satiate. A polymerization experiment using propylene was then carried out carried out as a feed, using the conditions of Example 4, a), however, BF3 was still not introduced into the reaction zone from the outside. The results of this experiment are given in Table IV below.

Table IV reaction time 0.5 hours 1 hour 3 hours Polymer yield, Weight percent. ... 21 28 I6 Boiling range of poly mers Beginning of boiling, ° .... 30 # 38 42 End of boiling point, ° (.... 82 II6 82 Bromine number of the distillate (1/100 g Br / g). ......... 48 75 64 The pretreated catalyst showed a high initial activity in contrast to both the untreated catalyst (Example 4, comparative experiments) and the untreated catalyst, in which BFs was fed in from the outside (Example 4).

The catalyst, however, did not achieve a high degree of activity, and activity decreased after about 1 hour. While the pre-treatment with BF3 the induction time necessary to achieve maximum catalytic activity abbreviated, it is necessary to add BF3 and / or catalyst complex to the catalyst zone to be supplied from the outside in order to achieve and maintain the maximum catalytic activity.

The catalyst can either be in liquid form or in the form of a Supported catalyst can be used according to methods such as those used in technology to carry out such processes are common for similar catalysts.

Claims (9)

PATENT CLAIMS: I. Process for olefin polymerization with boron fluoride-phosphoric acid catalysts, characterized in that the catalyst used is a at temperatures below +100 produced coordination compound of boron trifluoride and an acid of phosphorus used. 2. The method according to claim I, characterized in that the coordination compound from essentially equal molar proportions by reacting between about and + 4 ° is established. 3. The method according to claim I or 2, characterized in that the catalyst additionally contains a free acid of phosphorus and / or free boron trifluoride contains. 4. The method according to claim 3, characterized in that the weight ratio of free acid to coordination compound within the limits between about 1: 9 and 9: I lies. 5. The method according to claim I to 4, characterized in that one the process is carried out in the presence of B F3, which is supplied from the outside. 6. The method according to claim I to 5, characterized in that one the olefin material steadily with the coordination compound under polymerization conditions brings into contact, which on a finely divided solid support, such as an inert Solid, is arranged. 7. The method according to claim 6, characterized in that the carrier consists of an adsorbent such as activated carbon. 8. The method according to claim I to 7, characterized in that one the catalyst is pretreated with gaseous boron trifluoride before the polymerization. 9. The method according to claim 1 to 7, characterized in that one the coordination compound in liquid form to the catalyst during the polymerization feeds. IO. Method according to Claims I to 9, characterized in that the catalyst by reaction of an organic ether complex of BF3 with the Acid is produced. References: British Patent Specification No. 451,359, 453 854.