Process for manufacturing polyisobutene with a higher efficiency

Abstract

The present invention concerns a process for manufacturing polyisobutene with a higher efficiency and a constant product quality.

Description

[0001] 231664

[0002] 1

[0003] Process for Manufacturing Polyisobutene with a Higher Efficiency

[0004] Description

[0005] The present invention concerns a process for manufacturing polyisobutene with a higher efficiency and a constant product quality.

[0006] Polymerisation processes for the production of polyisobutene are long known and are subject to perpetual optimisation.

[0007] Recent findings have shown that in particular the presence of diisobutene has an impact on the composition of the reaction mixture and on the formation of isomers in the polyisobutene.

[0008] Rll 2160285 describes polymerisation of isobutene-containing monomer mixtures using aluminium chlorides. Unreacted monomer is distilled off the reaction mixture but not further analysed or rectified.

[0009] WO 2000 / 8075 A1 describes polymerisation of isobutene-containing monomer mixtures using hetero polyacids. Unreacted monomer is distilled off the reaction mixture and may be recycled into the reaction mixture. Isobutene oligomers remain in the reaction mixture and are distilled off the polyisobutene in a second distillation step downstream. The influence of the oligomers on the polymerisation is not recognised and control of the oligomer content in the recycled monomer stream is not provided.

[0010] EP 1134208 A1 describes conversion of lower oligomers of isobutene and optionally isobutene into higher oligomers of isobutene by distil lative separation of higher and lower oligomers, further reaction of the lower oligomers and full recycling of the lower oligomers. The lower oligomers and unreacted monomers are completely recycled. The influence of the oligomers on the polymerisation is not recognised and control of the oligomer content in the recycled monomer stream is not provided.

[0011] WO 2017 / 151339 A1 describes polymerisation of isobutene-containing monomer mixtures using boron trifluoride. Unreacted monomer is distilled off the reaction mixture and may be recycled into the polymerisation but is not further rectified.

[0012] WO 2003 / 20681 A1 describes addition of acetic acid to a mixture of 1,3-butadiene and isobutene forming butenyl- and butyl-acetates. Oligomers and acetates of oligomers may be distilled off the reaction mixture, however, no recycling is disclosed. In contrast, diisobutene is removed from the reaction mixture by distillation and led to hydrogenation and further utilisation.

[0013] US 8,524,843, US 9,856,335 B2, and US 9,598,655 describe the use of diisobutenes as chain transfer agents for controlling the molecular weight and controlling the content of highly reactive isomers in the polymer. 231664

[0014] 2

[0015] All examples according to US 8,524,843 and US 9,598,655 were conducted in a single passage through the reactor. Unreacted monomer was not reclaimed after reaction. Furthermore, according to US 8,524,843 polyisobutene with a multimodal distribution of molecular weight is obtained.

[0016] Since according to US 8,524,843 diisobutenes act as chain transfer agents (CTA) and, thus, have a severe impact on polymerisation, the person skilled in the art would not take into account recycling of diisobutenes, since a CTA terminates the desired growth of a polymer chain and starts a new one. Therefore, the presence of diisobutenes should be strictly controlled and preferably kept as low as possible, if not even zero.

[0017] Contrary to US 8,524,843, according to the present invention it has been found that diisobutenes may be incorporated into the polymer chain and may lead to isomers with internal vinylidene double bonds and / or isomers bearing a neopentyl sidechain. The polyisobutene exhibits a unimodal distribution of molecular weight.

[0018] Depending on the intended use of the polyisobutene the formation of such isomers may be wanted or unwanted.

[0019] WO 2004 / 101128 A2 discloses a manufacturing process for polyisobutene in which "unreacted monomers, dimers, oligomers and other undesired contaminants such as diluants etc." are separated from the polymer and may be recycled or diverted for other uses.

[0020] The process does not recognise the influence of such dimers and oligomers on the polymerisation and on the polyisobutene product.

[0021] It was an object of the present invention to provide a process for manufacturing polyisobutene with a higher efficiency of the reaction and a constant product quality. Formation of unwanted isomers or sub-structures should be kept at a minimum.

[0022] The problem was solved by a process for polymerisation of isobutene-containing monomer compositions yielding polyisobutene comprising at least the steps of

[0023] (a) providing an isobutene-containing monomer composition and optionally at least one solvent,

[0024] (b) polymerisation of the isobutene-containing monomer composition in the presence of at least one halide of boron, aluminium, iron, gallium, titanium, zinc or tin as Lewis acid forming a reac- 231664

[0025] 3 tion mixture comprising lower oligomers of isobutene, especially dimers and trimers, polyisobutene, and unreacted isobutene,

[0026] (c) stopping the polymerisation by deactivating the at least one Lewis acid,

[0027] (d) distilling off unreacted

[0028] - isobutene-containing monomer composition,

[0029] - dimers and trimers formed from the isobutene-containing monomer composition, and

[0030] - optionally solvent in one or more distillation steps from the reaction mixture obtained from step (c) forming a recycling stream,

[0031] (e) rectifying the recycling stream of step (d), thereby separating the recycling stream at least in

[0032] - a fraction (e in which isobutene is enriched and

[0033] - a fraction (en) in which dimers and trimers of isobutene is enriched,

[0034] (f) leading the rectified recycling stream (e obtained from step (e) at least partly into the polymerisation (b), wherein the content of dimers and trimers (in sum) in the combined streams fed into the polymerisation (b) is not more than 20000 ppm by weight, preferably not more than 15000, and more preferably not more than 10000 ppm by weight, wherein the isobutene-containing monomer composition in step (a) is pure isobutene or an isobutene-containing C4 hydrocarbon stream comprising less than 500 ppm of butadiene and optionally 1 -butene, cis- and trans-2-butene.

[0035] With the present process the content of diisobutenes is efficiently controlled and kept constant during the production of polyisobutene in order to ensure a uniform product quality. It has been found that diisobutenes can be accepted in the reaction mixture in a certain concentration range without a significant increase of isomers with an internal vinylidene double bond in the polyisobutene mixture obtained. Small amounts of diisobutenes can be acceptable due to their effect as chain transfer agent.

[0036] The process according to the present invention is advantageous since the capacity of an existing plant can be increased, the space-time-yield of the reaction is increased and the consump- 231664

[0037] 4 tion of the catalyst is reduced. By controlling the content of dimers and trimers of isobutene in the isobutene which is led back into the polymerisation the product quality of the polyisobutene produced according to the present invention is kept constant.

[0038] The thus obtained polyisobutene exhibits a narrower molecular weight distribution and is highly reactive. The content especially of isomers bearing an internal vinylidene double bond is affected by the content of such oligomers, especially diisobutenes. Contrary to the disclosure of US 8,524,843, the polyisobutene exhibits a unimodal molecular weight distribution.

[0039] If a low content of such isomers bearing an internal vinylidene double bond in the polyisobutene is sought, it constitutes one embodiment of the present invention to keep the content of dimers and trimers (in sum) in the combined streams, i.e. monomer stream (a) and recycling stream (e (in sum), fed into the polymerisation (b) at not more than 20000 ppm by weight. By keeping the amount of dimers and trimers in the feed streams low it is possible to minimise the content of isomers with an internal vinylidene-double bond (>C=CH2) at the polymer backbone in favour of the desired polyisobutene bearing alpha- and beta-double bond. On the other hand, presence of small amounts of dimers and trimers as chain transfer agents help controlling the molecular weight of the polyisobutene.

[0040] In this embodiment, preferably the content of dimers and trimers (in sum) in the combined streams, preferably in the recycling stream (e is not more than 15000, more preferably not more than 10000 ppm, even more preferably not more than 7500, especially not more than 5000, especially not more than 4000 ppm by weight, and even not more than 3000 ppm by weight. It may be advantageous to keep the content of not more than 2000 or even not more than 1000 ppm by weight.

[0041] With a reasonable effort in the rectification the content of dimers and trimers in the recycling stream (e cannot be reduced to substantially 0 (zero). It has been found that as a lower limit, a content of 5 ppm or less of dimers and trimers (in sum) in this stream is not detrimental, preferably 10 ppm, more preferably 15 ppm, even more preferably 25, especially of 50 ppm by weight, and even of 100 ppm or less.

[0042] The content of dimers and trimers in the monomer stream (a) often is not more than 50 ppm by weight, for example not higher that 40 ppm, preferably not higher than 30, even more preferably not higher than 20, especially not higher than 10, and even not higher than 5 ppm by weight. In case the feed stream (a) is treated in a certain manner (see below), the content of dimers and trimers in this stream may be higher. 231664

[0043] 5

[0044] Usually, the essential source of dimers and trimers in the combined streams fed into the polymerisation is recycling stream (ei_). Typically, 80% or more of all dimers and trimers fed into the polymerisation stem from recycling stream (ei_), preferably at least 85, more preferably at least 90, even more preferably at least 95, especially at least 98 or even at least 99%.

[0045] In a preferred embodiment, monomer stream (a) is essentially free of dimers and trimers of isobutene and recycling stream (e is the only essential source of oligomers fed into the polymerisation (b).

[0046] In another embodiment, if a polyisobutene is desired with a high content of isomers bearing an internal vinylidene double bond (>C=CH2) at the polymer backbone the content of dimers and trimers in the isobutene-containing streams fed into step (b) is higher, preferably more than 2.0 wt%, more preferably at least 2.5, even more preferably at least 3.0, especially at least 3.5, and even at least 4.0 wt%.

[0047] According to this embodiment, the amount of dimers and trimers in the isobutene-containing monomer composition fed into step (b) may for example be up to 15 wt%, preferably up to 12.5, even more preferably up to 10, especially up to 7.5, and even up to 5 wt%.

[0048] If not explicitly stated otherwise in the present document, the content of isobutene, and dimers and trimers in the isobutene refer to the total amount of polymerizable monomers, i.e. solvent and constituents which are non-reactive under the polymerisation conditions are excluded. Preferably the weight percentage refers to the sum of isobutene, diisobutene, and triisobutene. This is especially the case when pure isobutene is used as monomer feed.

[0049] With the present invention it is possible to produce both low as well as medium molecular polyisobutene:

[0050] The number-average molecular weight Mn(determined by gel permeation chromatography) of the medium molecular polyisobutene according to the present invention is from 10000 to 100000, preferably from 11000 to 90000, more preferably from 12000 to 80000, most preferably from 13000 to 75000, and especially from 14000 to 70000.

[0051] Medium molecular polyisobutene is usually referred to as highly reactive with a content of terminal (alpha-) double bonds of 10 to 60 mol%, preferably 15 to 55 mol%, more preferably 20 to 50 mol%, even more preferably 25 to 50 mol%, and especially at least 25 to 45 mol%. 231664

[0052] 6

[0053] In contrast, low molecular polyisobutene is defined as polyisobutene compositions with a number-average molecular weight Mnof not more than 10000 g / mol, preferably 280 to 7500, more preferably 330 to 6000, even more preferably 500 to 5000, especially 750 to 2500, and even 900 to 1100 g / mol.

[0054] Low molecular polyisobutene is usually referred to as highly reactive with a content of terminal (alpha-) double bonds of at least 50 mol%, preferably at least 60, more preferably at least 70, even more preferably at least 80, and especially at least 85 mol%. The content of such alphadouble bonds may be up to 100, up to 98, up to 97 or up to 95 mol%.

[0055] It has been found that polyisobutene comprises a mixture of different isomers with a different position and configuration of the double bond designated as follows: isomers (A) bearing an alpha-double bond isomers (B) bearing a beta-double bond and polyisobutene isomers (C) other than (A) and (B), selected from the group consisting of 231664 in which PIB, PIB' and PIB" refer to appropriately shortened polymeric backbones of the polyisobutene.

[0056] In the above-listed formulae (A) to (C9) the groups PIB, PIB' and respectively PIB" together with the explicitly shown substructures add up to a polyisobutene polymer with a numberaverage molecular weight Mnof more than 250 and up to 100000 g / mol. In other words, the groups PIB, PIB' and respectively PIB" refer to a polyisobutene polymer shortened by the explicitly shown substructures.

[0057] For low molecular polyisobutene with a number-average molecular weight Mnof from 250 up to 10000 g / mol the average degree of polymerisation is up to 177, preferably from 5 to 134, more preferably 6 to 107, even more preferably 9 to 89, especially 13 to 45, and even 16 to 20.

[0058] For medium molecular polyisobutene with a number-average molecular weight Mnof more than 10000 and up to 100000 g / mol the average degree of polymerisation is from 178 to 1786. 231664

[0059] 8

[0060] In an ideal homopolymer of isobutene the residues PI B, PI B' and PIB" stand for

[0061] PIB: -[-(H3C)2C-CH2-]m-,

[0062] PIB': -[-(H3C)2C-CH2-]n- and

[0063] PIB": -[-(H3C)2C-CH2-]O-, wherein the polymer chain, especially of PIB and PIB', may be started on an appropriate initiator, see below, preferably may be connected to hydrogen, with m, n and o independently of another each being positive integers, with the proviso that the sum of m, n, and o plus the monomer units in the shown substructures match the degree of polymerisation of the low or medium molecular polyisobutene.

[0064] In a copolymer some isobutene units may be replaced by other monomer units, e.g. 1-butene, cis or trans 2-butene, see below.

[0065] In the case of formulae (A), (B), (C1) to (C5), (C8) and (C9) the integers m and n can be up to the degree of polymerisation of the low or medium molecular polyisobutene minus 1 or 2.

[0066] In the case of formulae (C6) and (C7) the integers n and o add up to the degree of polymerisation of the low or medium molecular polyisobutene minus 1 .

[0067] Further to components (A), (B), and (C) the mixture may comprise other polyisobutene-derived species (D):

[0068] Furthermore, halogenated polyisobutenes (D1) may be found.

[0069] Furthermore, fully saturated polyisobutenes (D2) may be found, which do not comprise any multiple bonds at all and are not halogenated.

[0070] The halogen is preferably selected from the group consisting of fluorine, chlorine, and bromine, more preferably fluorine or chlorine, and especially chlorine.

[0071] Main origin of the halogen is the Lewis acid used as a catalyst for polymerisation or a halogencontaining initiator (see below), but can also be remaining solvent in the polyisobutene composition in case a halogenated solvent is used.

[0072] The halogen can be incorporated into the polyisobutene, such as isomer (D1) mentioned above, or can be part of the mixture without being chemically bound to polyisobutene. 231664

[0073] 9

[0074] In the embodiment in which a polyisobutene with a high content of isomers bearing an internal vinylidene double bond (>C=CH2) at the polymer backbone is desired, the polyisobutene comprises an increased amount of at least one of the isomers compared to a polymerisation process of an isobutene-containing monomer composition under the same reaction conditions with the absence of dimers and trimers of isobutene.

[0075] Furthermore, the content of isomer (C7) may further be increased which usually is formed in comparably higher amounts since it may be formed from isomer (C6) by way of isomerisation of the double bond.

[0076] The same is true for isomers (C9a) and (C9b)

[0077] (C9a)

[0078] (C9b) which are presumably formed from isomer (C9) by isomerisation of the internal vinylidene double bond in (C9) to the trisubstituted double bonds shown in the formulae.

[0079] Isomer (C8) is the product of a methyl group rearrangement.

[0080] In the broadest sense, according to the present invention polyisobutene isomers with an internal vinylidene-double bond (>C=CH2) are polyisobutene molecules bearing at least one, preferably exactly one vinylidene-double bond (>C=CH2) other than an alpha double bond. In other words, 231664

[0081] 10 one of the two substituents of the vinylidene-double bond (>C=CH2) is other than a methyl group and the other substituent is the polyisobutenyl residue. In a preferred embodiment and in the narrower sense of the present invention polyisobutene isomers with an internal vinylidene- double bond are the isomers (C6), (C8), and (C9), as well as mixtures thereof.

[0082] Therefore, subject matter of the present invention is a process for preparation of polyisobutene with an increased content of isomers with an internal vinylidene-double bond (>C=CH2) at the polymer backbone, selected from the group consisting of the isomers by polymerisation of isobutene-containing monomer compositions yielding polyisobutene comprising at least the steps of

[0083] (a) providing an isobutene-containing monomer composition and optionally at least one solvent,

[0084] (b) polymerisation of the isobutene-containing monomer composition in the presence of at least one halide of boron, aluminium, iron, gallium, titanium, zinc or tin as Lewis acid forming a reaction mixture of lower oligomers of isobutene, especially dimers and trimers, polyisobutene, and unreacted isobutene,

[0085] (c) stopping the polymerisation by deactivating the at least one Lewis acid,

[0086] (d) distilling off unreacted

[0087] - isobutene-containing monomer composition,

[0088] - dimers and trimers formed from the isobutene-containing monomer composition, and

[0089] - optionally solvent in one or more distillation steps from the reaction mixture obtained from step (c) forming a recy- 231664

[0090] 11 cling stream,

[0091] (e) rectifying the recycling stream of step (d), thereby separating the recycling stream at least in

[0092] - a fraction (e in which isobutene is enriched and

[0093] - a fraction (en) in which dimers and trimers of isobutene is enriched,

[0094] (f) leading the rectified recycling stream (e obtained from step (e) at least partly into the polymerisation (b), wherein the content of dimers and trimers (in sum) in the combined streams fed into the polymerisation (b) is more than 2.0 wt%, more preferably at least 2.5, even more preferably at least 3.0, especially at least 3.5, and even at least 4.0 wt%, wherein the content of isomers with an internal vinylidene-double bond (>C=CH2) at the polymer backbone is increased compared to a polymerisation process of an isobutene-containing monomer composition under the same reaction conditions with the absence of dimers and trimers of isobutene.

[0095] Such isomers with an internal vinylidene-double bond (>C=CH2) exhibit a high reactivity in thermal reactions, preferably a high reactivity in hydroformylation, thermal ene-reaction with maleic anhydride, or Friedel-Crafts alkylation of aromatic compounds. The reactivity is slightly lower than the reactivity of alpha-double bonds, however, sufficient to allow formation of derivatives of polyisobutene at an internal position of the polymer backbone.

[0096] In contrast, in the embodiment in which a low content of such isomers bearing an internal vinylidene double bond in the polyisobutene is sought, the content of isomers (C6), (C7), (C8), and (C9) is low in favour of isomers (A) and / or (B), preferably (A).

[0097] According to the present invention the content of a mixture of dimers and trimers in the polymerisation is controlled. Such a mixture usually comprises higher amounts of diisobutene than triisobutene, e.g more than 60 wt% diisobutene and less than 40 wt% triisobutene, preferably at least 75 wt% diisobutene and not more than 25 wt% triisobutene, very preferably at least 85 wt% diisobutene and not more than 15 wt% triisobutene, particularly preferably preferably at least 90 wt% diisobutene and not more than 10 wt% triisobutene, and especially at least 95 wt% diisobutene and not more than 5 wt% triisobutene. 231664

[0098] 12

[0099] The mixture may comprise higher oligomers of isobutene, such as tetraisobutene or pentaisobutene, however, the amount of such higher oligomers in the mixture is usually not more than 5 wt%, preferably not more than 3 wt%, very preferably not more than 2 wt%, particularly preferably not more than 1 wt%, and especially not more than 0.5 wt%.

[0100] By applying the rectification in step (e) it is possible to reduce the content of triisobutene in such a mixture of oligomers. The ratio of triisobutene : diisobutene after rectification is usually not more than 10 : 100, preferably not more than 5 : 100, more preferably not more than 2 : 100, and even more preferably not more than 1 : 100.

[0101] The ratio of higher oligomers of isobutene : diisobutene after rectification is usually not more than 1 : 100, preferably not more than 0.5 : 100, and more preferably not more than 0.1 : 100.

[0102] In a preferred embodiment of the present invention the dimers and trimers of isobutene are the following compounds: alpha-diisobutene (2,4,4-trimethylpent-1-ene): beta-diisobutene (2,4,4-trimethylpent-2-ene): alpha-triisobutene (2,4,4,6,6-pentamethylhept-1-ene): beta-triisobutene (2,4,4,6,6-pentamethylhept-2-ene): 231664

[0103] 13

[0104] Especially the content of alpha- and beta-diisobutene is controlled in the polymerisation.

[0105] The weight percentage of di- and triisobutene refers to the amount of all polymerizable compounds in the reaction mixture.

[0106] The invention is described in more detail as follows:

[0107] Step (a) - provision of an isobutene-containing monomer composition and optionally at least one solvent

[0108] For the use of isobutene or of an isobutene-comprising monomer mixture as the monomer to be polymerized, suitable isobutene sources are both pure isobutene and isobutenic C4 hydrocarbon streams.

[0109] The raw material of C4 compounds is usually selected from the group consisting of

[0110] (a) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding high purity isobutene having the isobutene amount of 90 to 100% by weight to C4 raffinate-1 which is a remainder after extracting 1,3-butadiene from a C4 compound derived during a naphtha degrading process;

[0111] (b) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding high amount isobutene mixture having isobutene amount of 80 to 97% by weight, which is generated in an olefin conversion unit (OCU) process that produces propylene by the metathesis of ethylene and 2-butene, to C4 raffinate-1 which is a remainder after extracting 1,3-butadiene from a C4 compound derived during a naphtha degrading process;

[0112] (c) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding high purity isobutene having the isobutene amount of 90 to 100% by weight to butane-butene oil (B-B oil) derived from crude oil refining process;

[0113] (d) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding high amount isobutene mixture having the isobutene amount of 80 to 97% by weight, which is generated in an olefin conversion unit (OCU) process that produces propylene by the metathesis of ethylene and 2-butene, to butane-butene oil (B-B oil) derived from crude oil refining process;

[0114] (e) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding a dilute solvent to high purity isobutene having an isobutene amount of 90 to 100% by weight;

[0115] (f) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding a dilute solvent to high amount isobutene mixture having the isobutene 231664

[0116] 14 amount of 80 to 97% by weight, which is generated in an olefin conversion unit (OCU) process that produces propylene by the metathesis of ethylene and 2-butene;

[0117] (g) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding high purity isobutene having the isobutene amount of 90 to 100% by weight to a mixture generated in dehydrogenation reaction that converts isobutane to isobutene; and

[0118] (h) a C4 compound material in which an isobutene amount is adjusted to 50 to 75% by weight, obtained by adding high amount isobutene mixture having the isobutene amount of 80 to 97% by weight, which is generated in an olefin conversion unit (OCU) process that produces propylene by the metathesis of ethylene and 2-butene to a mixture generated in dehydrogenation reaction that converts isobutane to isobutene.

[0119] Preferred are C4 raffinates, especially "raffinate 1", C4 cuts from isobutane dehydrogenation, C4 cuts from steam crackers and from FCC crackers (fluid catalyzed cracking), provided that they have been substantially freed of 1 ,3-butadiene present therein. A C4 hydrocarbon stream from an FCC refinery unit is also known as "b / b" stream. Further suitable isobutenic C4 hydrocarbon streams are, for example, the product stream of a propylene-isobutane cooxidation or the product stream from a metathesis unit, which are generally used after customary purification and / or concentration. Suitable C4 hydrocarbon streams generally comprise less than 500 ppm, preferably less than 200 ppm, of butadiene. The presence of 1 -butene and of cis- and trans-2-butene is substantially uncritical. Typically, the isobutene concentration in the C4 hydrocarbon streams mentioned is in the range from 40 to 60% by weight. For instance, raffinate 1 generally consists essentially of 30 to 50% by weight of isobutene, 10 to 50% by weight of 1 -butene, 10 to 40% by weight of cis- and trans-2-butene, and 2 to 35% by weight of butanes; in the polymerization process according to the invention, the unbranched butenes in the raffinate 1 generally behave virtually inertly, and only the isobutene is polymerized.

[0120] The content of compounds with five or more carbon atoms in C4 hydrocarbon streams should not exceed 2000 ppm by weight, preferably not exceed 1500 ppm, more preferably should not be higher than 1000 ppm, more preferably not higher than 750 ppm, and especially not higher than 500 ppm by weight.

[0121] The content of isoprene in the monomer composition usually should be less than 100 ppm by weight, preferably not more than 75 ppm, more preferably not more than 50 ppm, even more preferably not more than 40 ppm, and especially not more than 25 ppm, or even 20 ppm by weight. 231664

[0122] 15

[0123] In a preferred embodiment, the monomer source used for the polymerization is a technical C4 hydrocarbon stream with an isobutene content of 1 to 100% by weight, especially of 1 to 99% by weight, in particular of 1 to 90% by weight, more preferably of 30 to 60% by weight, especially a raffinate 1 stream, a b / b stream from an FCC refinery unit, a product stream from a propylene-isobutane cooxidation or a product stream from a metathesis unit.

[0124] Especially when a raffinate 1 stream is used as the isobutene source, the use of water as the sole initiator or as a further initiator has been found to be useful, in particular when polymerization is conducted at temperatures of -20°C to +30°C, especially of 0°C to +20°C. At temperatures of -20°C to +30°C, especially of 0°C to +20°C, when a raffinate 1 stream is used as the isobutene source, it is, however, also possible to dispense with the use of an initiator.

[0125] The isobutenic monomer mixture mentioned may comprise small amounts of contaminants such as water, carboxylic acids or mineral acids, without there being any critical yield or selectivity losses. It is appropriate to prevent enrichment of these impurities by removing such harmful substances from the isobutenic monomer mixture, for example by adsorption on solid adsorbents such as molecular sieves or predried oxides such as aluminum oxide, silicon dioxide, calcium oxide or barium oxide, activated carbon or ion exchangers.

[0126] It is known that such absorbents may lead to oligomerisation of isobutene so that the thus treated isobutene may contain small amounts of dimers and trimers of isobutene, see e.g. WO 2009 / 55227 A1 for certain zeolites. However, under the typical conditions of the treatment of the isobutene feed, the content of dimers and trimers of isobutene in the isobutene feed fed freshly into the polymerisation, their content is usually not more than 500 ppm by weight, preferably not more than 300, more preferably not more than 200, even more preferably not more than 100, and especially not more than 50 ppm by weight.

[0127] In a preferred embodiment, the conditions of the treatment of the isobutene feed (a) with the absorbent are chosen in a manner that the content of dimers and trimers of isobutene in the isobutene feed (a) fed into the polymerisation is not higher that 40 ppm, preferably not higher than 30, even more preferably not higher than 20, especially not higher than 10, and even not higher than 5 ppm by weight.

[0128] It is also possible to convert monomer mixtures of isobutene or of the isobutenic hydrocarbon mixture with olefinically unsaturated monomers copolymerizable with isobutene. When monomer mixtures of isobutene are to be copolymerized with suitable comonomers, the monomer mixture preferably comprises at least 5% by weight, more preferably at least 10% by weight and especially at least 20% by weight of isobutene, and preferably at most 95% by weight, more preferably at most 90% by weight and especially at most 80% by weight of comonomers.

[0129] Useful copolymerizable monomers include: vinylaromatics such as styrene and a-methylstyrene, Ci- to C4-alkylstyrenes such as 2-, 3- and 4-methylstyrene, and 4-tert-butylsty- rene, halostyrenes such as 2-, 3- or 4-chlorostyrene, and isoolefins having 5 to 10 carbon atoms, such as 2-methylbutene-1 , 2-methylpentene-1 , 2-methylhexene-1 , 2-ethylpentene-1 , 2- ethylhexene-1 and 2-propylheptene-1. Further useful comonomers include olefins which have a silyl group, such as 1 -trimethoxysilylethene, 1-(trimethoxysilyl)propene, 1-(trimethoxysilyl)-2- methylpropene-2, 1-[tri(methoxyethoxy)-silyl]ethene, 1-[tri(methoxyethoxy)silyl]propene, and 1-[tri(methoxyethoxy)silyl]-2-methylpro-pene-2. In addition - depending on the polymerization conditions - useful comonomers also include isoprene, 1 -butene and cis- and trans-2-butene.

[0130] When the process according to the invention is to be used to prepare copolymers, the process can be configured so as to preferentially form random polymers or to preferentially form block copolymers. To prepare block copolymers, for example, the different monomers can be supplied successively to the polymerization reaction, in which case the second comonomer is especially not added until the first comonomer is already at least partly polymerized. In this manner, diblock, triblock and higher block copolymers are obtainable, which, according to the sequence of monomer addition, have a block of one or the other comonomer as a terminal block. In some cases, however, block copolymers also form when all comonomers are supplied to the polymerization reaction simultaneously, but one of them polymerizes significantly more rapidly than the other(s). This is the case especially when isobutene and a vinylaromatic compound, especially styrene, are copolymerized in the process according to the invention. This preferably forms block copolymers with a terminal polystyrene block. This is attributable to the fact that the vinylaromatic compound, especially styrene, polymerizes significantly more slowly than isobutene.

[0131] The isobutene or the isobutene containing C4 hydrocarbon stream can at least partially, preferably completely, originate from renewable sources, as described for example in WO 2012 / 40859 A1 , particularly from page 5, line 9 to page 6, line 24. The proportion of isobutene from renewable sources in the total amount of isobutene used, measured according to ASTM D 6866 as described in WO 2012 / 40859 A1 , is advantageously at least 1 wt%, preferably at least 2 wt%, particularly preferably at least 10 wt%, especially preferably at least 25 wt%, and specifically at least 50 wt%. The proportion of isobutene from renewable sources can be up to 100 wt%, preferably up to 95 wt%, particularly preferably up to 90 wt%, especially preferably up to 85 wt%, and specifically up to 80 wt%. 17

[0132] In a preferred embodiment of the present invention, the isobutene used in the isobutene- comprising monomer mixture resp. in the polyisobutene has a biobased fraction, measured as a14C:12C ratio ASTM-D6866, of more than 0%, preferably at least 1%, particularly preferably at least 5%, even more preferably at least 10%, especially at least 20%, and specifically at least 25%.

[0133] Advantageously, this biobased fraction can be at least 30%, preferably at least 40%, particularly preferably at least 50%, even more preferably at least 66%, especially at least 75%, and specifically at least 85%.

[0134] At a fraction of at least 90%, preferably at least 95%, particularly preferably at least 98%, and even 100%, this can be referred to as significantly predominant or completely biobased isobutene.

[0135] According to this embodiment, resources are conserved and the product is produced at least partially with renewable raw materials.

[0136] In another embodiment of the present invention, the isobutene used in the polymerization can be obtained entirely from renewable raw materials or consist of mixtures of isobutene from renewable and fossil sources.

[0137] The latter embodiment is particularly preferred as long as isobutene from renewable sources is not available in industrially sufficient quantities and economically viable.

[0138] The terms "renewable" or "bio-based" used herein with regard to a material or a compound (such as alcohols, alkyl, olefins, di-olefins, etc.) denote a material or compound obtained from a "new carbon" source as measured by ASTM test method designated as D 6866, "Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis", incorporated herein by reference in its entirety. This test method measures the14C / 12C isotope ratio in a sample and compares it to the14C / 12Cisotope ratio in a standard 100% bio-based material to give percent biobased content of the sample.

[0139] "Renewable" or "bio-based" compounds can be prepared from biomass using thermochemical methods (e.g., Fischer-Tropsch catalysts), biocatalysts (e.g., fermentation), or other processes.

[0140] All types of polymers made with the isobutene of this invention are verifiable as being made with isobutene that did not originate from a petrochemical source. Additionally, the isobutene con- 231664

[0141] 18 taining polymers of this invention can also be distinguished from isobutene containing polymers that come from natural sources, such as natural rubber. Accordingly, the isobutene containing polymers of this invention are analytically verifiable as coming from the bio- renewable, environmentally friendly sources. Assessment of the renewably based carbon content of a material can be performed through standard test methods, e.g. using radiocarbon and isotope ratio mass spectrometry analysis. ASTM International (formally known as the American Society for Testing and Materials) has established a standard method for assessing the biobased content of materials. The ASTM method is designated ASTM-D6866.

[0142] The application of ASTM-D6866 to derive "biobased content" is built on the same concepts as radiocarbon dating, but without use of the age equations. The analysis is performed by deriving a ratio of the amount of radiocarbon (14C) in an unknown sample compared to that of a modern reference standard. This ratio is reported as a percentage with the units "pMC"(percent modern carbon). If the material being analyzed is a mixture of present day radiocarbon and fossil carbon (containing very low levels of radiocarbon), then the pMC value obtained correlates directly to the amount of biomass material present in the sample. "Biobased materials" are organic materials in which the carbon comes from recently (on a human time scale) fixated CO2 present in the atmosphere using sunlight energy (photosynthesis). On land, this CO2 is captured or fixated by plant life (e.g., agricultural crops or forestry materials). In the oceans, the CO2 is captured or fixated by photosynthesizing bacteria or phytoplankton. For example, a biobased material has a14C / 12C isotope ratio greater than 0. Contrarily, a fossil-based material, has a14C / 12C isotope ratio of about 0.

[0143] A small amount of the carbon atoms of the carbon dioxide in the atmosphere is the radioactive isotope14C, which is created when atmospheric nitrogen is struck by a cosmic ray generated neutron, causing the nitrogen to lose a proton and form carbon of atomic mass 14 (14C), which is then immediately oxidized to carbon dioxide. A small but measurable fraction of atmospheric carbon is present in the form of14CC>2. Atmospheric carbon dioxide is processed by green plants to make organic molecules during the process known as photosynthesis. Virtually all forms of life on Earth depend on this green plant production of organic molecules to produce the chemical energy that facilitates growth and reproduction. Therefore, the14C that forms in the atmosphere eventually becomes part of all life forms and their biological products, enriching biomass and organisms which feed on biomass with14C. In contrast, carbon from fossil fuels does not have the signature14C:12C ratio of renewable organic molecules derived from atmospheric carbon dioxide. 231664

[0144] 19

[0145] To achieve a desired biobased content in an isobutene-based polymer, the mixture ratio of biobased isobutene to petroleum based isobutene in the polymer may be varied. In one embodiment, the biobased content for the isobutene-based elastomer of the present invention is greater than 0%. In another embodiment, the biobased content for the isobutene-based elastomer is greater than 20%. In another embodiment, the biobased content for the isobutene-based elastomer is greater than 40%. In another embodiment, the biobased content for the isobutene- based elastomer is greater than 60%. In another embodiment, the biobased content for the iso- butene-based elastomer is greater than 80%. In another embodiment, the biobased content for the isobutene-based elastomer is greater than 90%. Alternatively or additionally, the multiolefin content of the final polymer can be modified by adjusting the multiolefin monomer feed for the polymerization reaction. For example, 4 mol% (petroleum-based isoprene, renewable isoprene or mixtures thereof) incorporation of isoprene into the final butyl polymer would result in a biobased content of between 5 to 95% (ASTM D6866). As another example, 0.9 mol% (petroleum-based isoprene, renewable isoprene or mixtures thereof) incorporation of isoprene into the final butyl polymer would result in a biobased content of between 1 to 99% (ASTM D6866). Polymerization of a butyl rubber polymer using biobased isoprene and bio-isobutene will yield a bio-butyl rubber with a bio-based content of 100% (ASTM D6866).

[0146] The present invention also relates to a method for verifying that a polymer having repeating units derived from isobutene contains isobutene that is obtained from a renewable non- petroleum derived hydrocarbon source. This method involves (a) determining the biobased content of the polymer; and (b) verifying that the polymer is from a renewable non-petroleum derived source if the biobased content (as described in ASTM D6866) of greater than 0%.

[0147] The verification method can be applied to homopolymers or copolymer of isobutene. In one embodiment, the method relates to verifying if a block copolymer having repeating units derived from isobutene contains isobutene that is from a renewable, sustainable non- petroleum derived source which comprises: (a) determining the percent modern carbon of at least one polyisobutene block in the copolymer; and (b) verifying that the isobutene from the copolymer is from a renewable, sustainable non-petroleum derived source if polyisobutene block has a total biobased content (ASTM D6866-08) greater than 0%.

[0148] Step (b) - polymerisation of the isobutene-containing monomer composition in the presence of at least one Lewis acid 231664

[0149] 20

[0150] For the preparation of such polyisobutene compositions according to the present invention usually isobutene or an isobutenic starting material is polymerised in the presence of at least one Lewis Acid-donor complex and an initiator.

[0151] Further to the isobutene or isobutenic starting material, according to the present invention the rectified recycling stream (e obtained from step (e) with the specified content of diisobutene and triisobutene is at least partly fed into the polymerisation (b).

[0152] As a Lewis Acid usually metal halides are used, namely halides of boron, aluminium, iron, gallium, titanium, zinc or tin.

[0153] Typical examples are boron trifluoride, boron trichloride, aluminum trihalide, alkylaluminum dihalide, dialkylaluminum halide, iron trihalide, gallium trihalide, titanium tetrahalide, zinc dihalide, tin dihalide, tin tetrahalide, wherein the halide is preferably fluoride or chloride, more preferably chloride.

[0154] Preferred are boron trifluoride, aluminum trichloride, alkyl aluminum dichloride, dialkyl aluminum chloride, and iron trichloride, more preferred are boron trifluoride, aluminum trichloride, and alkyl aluminum dichloride, most preferred are boron trifluoride and aluminum trichloride with boron trifluoride being especially preferred.

[0155] Examples for suitable donor compounds comprise at least one oxygen and / or nitrogen atom with at least one lone electron pair, preferably at least one oxygen atom with at least one lone electron pair and very preferably are selected from the group consisting of organic compounds with at least one ether function, organic compounds with at least one carboxylic ester function, organic compounds with at least one aldehyde function, organic compounds with at least one keto function, and organic compounds with at least one nitrogen containing heterocyclic ring.

[0156] Solely oxygen containing donor compounds are preferred over nitrogen-containing donor compounds.

[0157] Preferably the donor is selected from the group consisting of organic compounds with at least one ether function, organic compounds with at least one carboxylic ester function and organic compounds with at least one keto function, more preferably selected from the group consisting of organic compounds with at least one ether function and organic compounds with at least one carboxylic ester function, very preferably donors are organic compounds with at least one ether function, and especially organic compounds with exactly one ether function. 231664

[0158] 21

[0159] Compounds with at least one ether function are also understood to mean acetals and hemiacetals. The ether compound may comprise one or more ether functions, e.g. one, two, three, four or even more ether functions, preferably one or two ether functions and very preferably one ether function.

[0160] The mixture of donors may comprise one, two, three, four or even more different compounds, preferably compounds with at least one ether function, preferably one or two different compounds and very preferably one compound.

[0161] It may be an advantage to use a mixture of two different donors, especially two different ethers, see e.g. WO 2017 / 1140603 for aluminium halide-donor complexes

[0162] In a preferred embodiment of the present invention, a boron trihalide-donor complex, an aluminum trihalide-donor complex or an alkylaluminum halide complex, or an iron trihalide-donor complex, or a gallium trihalide-donor complex or a titanium tetrahalide-donor complex or a zinc dihalide-donor complex or a tin dihalide-donor complex or the tin tetrahalide-donor complex or the boron trihalide-donor complex, very preferably a boron trihalide-donor complex, an aluminum trihalide-donor complex or an iron trihalide-donor complex or a boron trihalide-donor complex and especially a boron trihalide-donor complex or an aluminum trihalide-donor complex is used, which comprises, as the donor, at least one dihydrocarbyl ether the general formula R8-O- R9in which the variables R8and R9are each independently Ci- to C2o-alkyl radicals, preferably Ci- to Cs alkyl radicals especially Ci- to C4 alkyl radicals, Ci- to C2o-haloalkyl radicals, preferably Ci- to Cs haloalkyl radicals especially Ci- to C4 haloalkyl radicals, C5- to Cs-cycloalkyl radicals, preferably Cs- to Cs-cycloalkyl radicals, Cs- to C2o-aryl radicals, especially Cs- to C12 aryl radicals, Cs- to C2o-haloaryl radicals, especially Cs- to C12 haloaryl radicals, or C7- to C2o-arylalkyl radicals, especially C7- to Ci2-arylalkyl radicals. Preference is given to Ci- to C4 alkyl radicals, Ci- to C4 haloalkyl radicals, Cs- to C12 aryl radicals, and C7- to Ci2-arylalkyl radicals

[0163] Haloalkyl and haloaryl mean preferably chloroalkyl or bromoalkyl and chloroaryl or bromoaryl, very preferably chloroalkyl and chloroaryl. Especially preferred are w-haloalkyl radicals.

[0164] Preferred examples are chloromethyl, 1-chloroeth-1-yl, 2-chloroeth-1-yl, 2-chloroprop-1-yl, 2- chloroprop-2-yl, 3-chloroprop-1-yl, and 4-chlorobut-1-yl.

[0165] Preferred examples for chloroaryl are 2-chlorophenyl, 3-chlorophenyl, and 4-chlorophenyl. 231664

[0166] 22

[0167] The dihydrocarbyl ethers mentioned may be open-chain or cyclic, where the two variables R8and R9in the case of the cyclic ethers may join to form a ring, where such rings may also comprise two or three ether oxygen atoms. Examples of such open-chain and cyclic dihydrocarbyl ethers are dimethyl ether, chloromethyl methyl ether, bis (chloromethyl) ether, diethyl ether, chloromethyl ethyl ether, 2-chloroethyl ethyl ether (CEE), bis (2-chloroethyl) ether (CE), di-n- propyl ether, diisopropyl ether, di-n-butyl ether, di-sec-butyl ether, diisobutyl ether, di-n-pentyl ether, di-n-hexyl ether, di-n-heptyl ether, di-n-octyl ether, di-(2-ethylhexyl) ether, methyl n-butyl ether, methyl sec-butyl ether, methyl isobutyl ether, methyl tert-butyl ether, ethyl n-butyl ether, ethyl sec-butyl ether, ethyl isobutyl ether, ethyl tert-butyl ether, n-propyl-n-butyl ether, n-propyl sec-butyl ether, n-propyl isobutyl ether, n-propyl tert-butyl ether, isopropyl n-butyl ether, isopropyl sec-butyl ether, isopropyl isobutyl ether, isopropyl tert-butyl ether, methyl n-hexyl ether, methyl n-octyl ether, methyl 2-ethylhexyl ether, ethyl n-hexyl ether, ethyl n-octyl ether, ethyl 2- ethylhexyl ether, n-butyl n-octyl ether, n-butyl 2-ethylhexyl ether, tetrahydrofuran, tetrahydropyran, 1 ,2-, 1 ,3- and 1 ,4-dioxane, dicyclohexyl ether, diphenyl ether, alkyl aryl ethers, such as anisole and phenetole, ditolyl ether, dixylyl ether and dibenzyl ether.

[0168] Furthermore, difunctional ethers such as dialkoxybenzenes, preferably dimethoxybenzenes, very preferably veratrol, and ethylene glycol dialkylethers, preferably ethylene glycol dimethylether and ethylene glycol diethylether, are preferred.

[0169] Among the dihydrocarbyl ethers mentioned, diethyl ether, 2-chloroethyl ethyl ether, diisopropyl ether, di-n-butyl ether and diphenyl ether have been found to be particularly advantageous as donors for the boron trihalide-donor complexes, the aluminum trihalide-donor complexes or the alkylaluminum halide complexes or the iron trihalide-donor complexes or the gallium trihalide- donor complex or the titanium tetrahalide-donor complex or the zinc dihalide-donor complex or the tin dihalide-donor complex or the tin tetrahalide-donor complex or the boron trihalide-donor complex, very preferably boron trihalide-donor complexes, the aluminum trihalide-donor complexes or iron trihalide-donor complexes or boron trihalide-donor complex and especially the a boron trihalide-donor complexes or the aluminum trihalide-donor complexes.

[0170] In a preferred embodiment dihydrocarbyl ethers with at least one secondary or tertiary dihydrocarbyl group are preferred over dihydrocarbyl groups with primary groups only. Ethers with primary dihydrocarbyl groups are those ethers in which both dihydrocarbyl groups are bound to the ether functional group with a primary carbon atom, whereas ethers with at least one secondary or tertary dihydrocarbyl group are those ethers in which at least one dihydrocarbyl group is bound to the ether functional group with a secondary or tertiary carbon atom. For the sake of clarity, e.g. diisobutyl ether is deemed to be an ether with primary dihydrocarbyl groups, since the secondary carbon atom of the isobutyl group is not bound to the oxygen of the functional ether group but the hydrocarbyl group is bound via a primary carbon atom.

[0171] Preferred examples for ethers with primary dihydrocarbyl groups are diethyl ether, di-n-butyl ether, and di-n-propyl ether.

[0172] Preferred examples for ethers with at least one secondary or tertary dihydrocarbyl group are diisopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, and anisole.

[0173] In addition, particularly advantageous dihydrocarbyl ethers as donors for the boron trihalide- donor complexes, the aluminum trihalide-donor complexes or the alkylaluminum halide complexes, have been found to be those in which the donor compound has a total carbon number of 3 to 16, preferably of 4 to 16, especially of 4 to 12, in particular of 4 to 8.

[0174] In another preferred embodiment halide-substituted ethers are preferred in combination with aluminum halide-donor complex or iron halide-donor complex or boron halide-donor complex.

[0175] Organic compounds with at least one carboxylic ester function are preferably hydrocarbyl carboxylates of the general formula R10-COOR11in which the variables R10and R11are each independently Ci- to C2o-alkyl radicals, especially Ci- to Cs alkyl radicals, Cs- to Cs-cycloalkyl radicals, Cs- to C2o-aryl radicals, especially Cs- to C12 aryl radicals, or C7- to C2o-arylalkyl radicals, especially C7- to Ci2-arylalkyl radicals.

[0176] Examples of the hydrocarbyl carboxylates mentioned are methyl formate, ethyl formate, n-pro- pyl formate, isopropyl formate, n-butyl formate, sec-butyl formate, isobutyl formate, tert-butyl formate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, secbutyl acetate, isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, sec-butyl propionate, isobutyl propionate, tert-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-bu- tyl butyrate, sec-butyl butyrate, isobutyl butyrate, tert-butyl butyrate, methyl cyclohexanecarboxylate, ethyl cyclohexanecarboxylate, n-propyl cyclohexanecarboxylate, isopropyl cyclohexanecarboxylate, n-butyl cyclohexanecarboxylate, sec-butyl cyclohexanecarboxylate, isobutyl cyclohexanecarboxylate, tert-butyl cyclohexanecarboxylate, methyl benzoate, ethyl benzoate, n-pro- pyl benzoate, isopropyl benzoate, n-butyl benzoate, sec-butyl benzoate, isobutyl benzoate, tertbutyl benzoate, methyl phenylacetate, ethyl phenylacetate, n-propyl phenylacetate, isopropyl phenylacetate, n-butyl phenylacetate, sec-butyl phenylacetate, isobutyl phenylacetate and tert- 24 butyl phenylacetate. Among the hydrocarbyl carboxylates mentioned, ethyl acetate has been found to be particularly advantageous as a donor for the complexes.

[0177] In addition, particularly advantageous hydrocarbyl carboxylates as donors, have been found to be those in which the donor compound has a total carbon number of 3 to 16, preferably of 4 to 16, especially of 4 to 12, in particular of 4 to 8, preference is given in particular to those having a total of 3 to 10 and especially 4 to 6 carbon atoms.

[0178] Organic compounds with at least one aldehyde function, preferably exactly one aldehyde function and organic compounds with at least one keto function, preferably exactly one keto function typically have from 1 to 20, preferably from 2 to 10 carbon atoms. Functional groups other than the carbonyl group are preferably absent.

[0179] Preferred organic compounds with at least one aldehyde function are those of formula R10-CHO, in which R10has the above-mentioned meaning, very preferably are selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, and benzaldehyde.

[0180] Preferred organic compounds with at least one keto function are those of formula R10-(C=O)- R11, in which R10and R11have the above-mentioned meaning, very preferably are selected from the group consisting of acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, and benzophenone. Greatest preference is given to acetone.

[0181] Organic compounds with at least one nitrogen containing heterocyclic ring are preferably saturated, partly unsaturated or unsaturated nitrogen-containing five-membered or six-membered heterocyclic rings which comprises one, two or three ring nitrogen atoms and may have one or two further ring heteroatoms from the group of oxygen and sulphur and / or hydrocarbyl radicals, especially Ci- to C4-alkyl radicals and / or phenyl, and / or functional groups or heteroatoms as substituents, especially fluorine, chlorine, bromine, nitro and / or cyano, for example pyrrolidine, pyrrole, imidazole, 1 ,2,3- or 1 ,2,4-triazole, oxazole, thiazole, piperidine, pyrazane, pyrazole, pyridazine, pyrimidine, pyrazine, 1 ,2,3-, 1 ,2,4- or 1 ,2,5-triazine, 1 ,2,5-oxathiazine, 21-1-1 ,3,5- thiadiazine or morpholine.

[0182] However, a very particularly suitable nitrogen-containing basic compound of this kind is pyridine or a derivative of pyridine (especially a mono-, di- or tri-Ci- to C4-alkyl-substituted pyridine) such as 2-, 3-, or 4-methylpyridine (picolines), 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5- or 3,6-dimethylpyridine 231664

[0183] 25

[0184] (lutidines), 2,4,6-trimethylpyridine (collidine), 2-, 3,- or 4-tert-butylpyridine, 2-tert-butyl-6-methyl- pyridine, 2,4-, 2,5-, 2,6- or 3,5-di-tert-butylpyridine or else 2-, 3,- or 4-phenylpyridine.

[0185] Initiator:

[0186] The polymerization is preferably performed with additional use of a mono- or polyfunctional, especially mono-, di- or trifunctional, initiator which is selected from organic hydroxyl compounds, organic halogen compounds and water. It is also possible to use mixtures of the initiators mentioned, for example mixtures of two or more organic hydroxyl compounds, mixtures of two or more organic halogen compounds, mixtures of one or more organic hydroxyl compounds and one or more organic halogen compounds, mixtures of one or more organic hydroxyl compounds and water, or mixtures of one or more organic halogen compounds and water. The initiator may be mono-, di- or polyfunctional, i.e. one, two or more hydroxyl groups or halogen atoms, which start the polymerization reaction, may be present in the initiator molecule. In the case of di- or polyfunctional initiators, telechelic isobutene polymers with two or more, especially two or three, polyisobutene chain ends are typically obtained.

[0187] Organic hydroxyl compounds which have only one hydroxyl group in the molecule and are suitable as monofunctional initiators include especially alcohols and phenols, in particular those of the general formula R12-OH, in which R12denotes Ci- to C2o-alkyl radicals, especially Ci- to Cs- alkyl radicals, Cs- to Cs-cycloalkyl radicals, Ce- to C2o-aryl radicals, especially Ce- to Ci2-aryl radicals, or Cy to C2o-arylalkyl radicals, especially Cy to Ci2-arylalkyl radicals. In addition, the R12radicals may also comprise mixtures of the abovementioned structures and / or have other functional groups than those already mentioned, for example a keto function, a nitroxide or a carboxyl group, and / or heterocyclic structural elements.

[0188] Typical examples of such organic monohydroxyl compounds are methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-ethylhexanol, cyclohexanol, phenol, p-methoxyphenol, o-, m- and p-cresol, benzyl alcohol, p-methoxybenzyl alcohol, 1- and 2-phenylethanol, 1- and 2-(p-methoxyphenyl)ethanol, 1-, 2- and 3-phenyl-1-propanol, 1-, 2- and 3-(p-methoxyphenyl)-1-propanol, 1- and 2-phenyl-2- propanol, 1- and 2-(p-methoxyphenyl)-2-propanol, 1-, 2-, 3- and 4-phenyl-1-butanol, 1-, 2-, 3- and 4-(p-methoxyphenyl)-1-butanol, 1-, 2-, 3- and 4-phenyl-2-butanol, 1-, 2-, 3- and 4-(p-me- thoxyphenyl)-2-butanol, 9-methyl-9H-fluoren-9-ol, 1 ,1 -diphenylethanol, 1 ,1-diphenyl-2-propyn-1- ol, 1 ,1 -diphenylpropanol, 4-(1 -hydroxy-1 -phenylethyl)benzonitrile, cyclopropyldiphenylmethanol, 1 -hydroxy-1 , 1-diphenylpropan-2-one, benzilic acid, 9-phenyl-9-fluorenol, triphenylmethanol, diphenyl(4-pyridinyl)methanol, alpha, alpha-diphenyl-2-pyridinemethanol, 4-methoxytrityl alcohol 231664

[0189] 26

[0190] (especially polymer-bound as a solid phase), alpha-tert-butyl-4-chloro-4’-methylbenzhydrol, cyclohexyldiphenylmethanol, alpha-(p-tolyl)-benzhydrol, 1 ,1 ,2-triphenylethanol, alpha, alpha- diphenyl-2-pyridineethanol, alpha, alpha-4-pyridylbenzhydrol N-oxide, 2-fluorotriphenylmethanol, triphenylpropargyl alcohol, 4-[(diphenyl)hydroxymethyl]benzonitrile, 1-(2,6-dimethoxyphenyl)-2- methyl-1-phenyl-1 -propanol, 1 ,1 ,2-triphenylpropan-1-ol and p-anisaldehyde carbinol.

[0191] In a preferred embodiment it is possible to use a mixture of primary and secondary alcohols as initiators, as described in WO 2013 / 120859.

[0192] Organic hydroxyl compounds which have two hydroxyl groups in the molecule and are suitable as bifunctional initiators are especially dihydric alcohols or diols having a total carbon number of 2 to 30, especially of 3 to 24, in particular of 4 to 20, and bisphenols having a total carbon number of 6 to 30, especially of 8 to 24, in particular of 10 to 20, for example ethylene glycol, 1 ,2- and 1 ,3-propylene glycol, 1 ,4-butylene glycol, 1 ,6-hexylene glycol, 1 ,2-, 1 ,3- or 1 ,4-bis(1- hydroxy-1-methylethyl)benzene (o-, m- or p-dicumyl alcohol), bisphenol A, 9,10-di-hydro-9,10- dimethyl-9,10-anthracenediol, 1 ,1-diphenylbutane-1 ,4-diol, 2-hydroxytriphenylcarbinol and 9-[2- (hydroxymethyl)phenyl]-9-fluorenol.

[0193] Organic halogen compounds which have one halogen atom in the molecule and are suitable as monofunctional initiators are in particular compounds of the general formula R13-Hal in which Hal is a halogen atom selected from fluorine, iodine and especially chlorine and bromine, and R13denotes Ci- to C2o-alkyl radicals, especially Ci- to Cs-alkyl radicals, Cs- to Cs-cycloalkyl radicals or C7- to C2o-arylalkyl radicals, especially C7- to Ci2-arylalkyl radicals. In addition, the R13radicals may also comprise mixtures of the abovementioned structures and / or have other functional groups than those already mentioned, for example a keto function, a nitroxide or a carboxyl group, and / or heterocyclic structural elements.

[0194] Typical examples of such monohalogen compounds are methyl chloride, methyl bromide, ethyl chloride, ethyl bromide, 1 -chloropropane, 1 -bromopropane, 2-chloropropane, 2-bromopropane, 1 -chlorobutane, 1 -bromobutane, sec-butyl chloride, sec-butyl bromide, isobutyl chloride, isobutyl bromide, tert-butyl chloride, tert-butyl bromide, 1 -chloropentane, 1 -bromopentane, 1 -chloro- hexane, 1 -bromohexane, 1 -chloroheptane, 1 -bromoheptane, 1 -chlorooctane, 1 -bromooctane, 1- chloro-2-ethylhexane, 1-bromo-2-ethylhexane, cyclohexyl chloride, cyclohexyl bromide, benzyl chloride, benzyl bromide, 1-phenyl-1 -chloroethane, 1-phenyl-1 -bromoethane, 1-phenyl-2-chloro- ethane, 1-phenyl-2-bromoethane, 1-phenyl-1 -chloropropane, 1-phenyl-1 -bromopropane, 1-phe- nyl-2-chloropropane, 1-phenyl-2-bromopropane, 2-phenyl-2-chloropropane, 2-phenyl-2-bromo- propane, 1-phenyl-3-chloropropane, 1-phenyl-3-bromopropane, 1-phenyl-1 -chlorobutane, 1- 231664

[0195] 27 phenyl-1 -bromobutane, 1-phenyl-2-chlorobutane, 1-phenyl-2-bromobutane, 1-phenyl-3-chloro- butane, 1-phenyl-3-bromobutane, 1-phenyl-4-chlorobutane, 1-phenyl-4-bromobutane, 2-phenyl-

[0196] 1 -chlorobutane, 2-phenyl-1 -bromobutane, 2-phenyl-2-chlorobutane, 2-phenyl-2-bromobutane,

[0197] 2-phenyl-3-chlorobutane, 2-phenyl-3-bromobutane, 2-phenyl-4-chlorobutane and 2-phenyl-4- bromobutane.

[0198] Organic halogen compounds which have two halogen atoms in the molecule and are suitable as difunctional initiators are, for example, 1 ,3-bis(1-bromo-1-methylethyl)benzene, 1 ,3-bis(2-chloro- 2-propyl)benzene (1 ,3-dicumyl chloride) and 1 ,4-bis(2-chloro-2-propyl)benzene (1 ,4-dicumyl chloride).

[0199] The initiator is more preferably selected from organic hydroxyl compounds in which one or more hydroxyl groups are each bonded to an sp3-hybridized carbon atom, organic halogen compounds, in which one or more halogen atoms are each bonded to an sp3-hybridized carbon atom, and water. Among these, preference is given in particular to an initiator selected from organic hydroxyl compounds in which one or more hydroxyl groups are each bonded to an sp3- hybridized carbon atom.

[0200] In the case of the organic halogen compounds as initiators, particular preference is further given to those in which the one or more halogen atoms are each bonded to a secondary or especially to a tertiary sp3-hybridized carbon atom.

[0201] Preference is given in particular to initiators which may bear, on such an sp3-hydridized carbon atom, in addition to the hydroxyl group, the R12, R13and R14radicals, which are each independently hydrogen, Ci- to C2o-alkyl, Cs- to Cs-cycloalkyl, Ce- to C2o-aryl, Cy to C2o-alkylaryl or phenyl, where any aromatic ring may also bear one or more, preferably one or two, Ci- to C4- alkyl, Ci- to C4-alkoxy, Ci- to C4-hydroxyalkyl or Ci- to C4-haloalkyl radicals as substituents, where not more than one of the variables R12, R13and R14is hydrogen and at least one of the variables R12, R13and R14is phenyl which may also bear one or more, preferably one or two, Ci- to C4-alkyl, Ci- to C4-alkoxy, Ci- to C4-hydroxyalkyl or Ci- to C4-haloalkyl radicals as substituents.

[0202] For the present invention, very particular preference is given to initiators selected from water, methanol, ethanol, 1-phenylethanol, 1-(p-methoxyphenyl)ethanol, n-propanol, isopropanol, 2- phenyl-2-propanol (cumene), n-butanol, isobutanol, sec.-butanol, tert-butanol, 1-phenyl-1- chloroethane, 2-phenyl-2-chloropropane (cumyl chloride), tert-butyl chloride and 1 ,3- or 1 ,4- bis(1 -hydroxy-1 -methylethyl)benzene. Among these, preference is given in particular to initiators 231664

[0203] 28 selected from water, methanol, ethanol, 1 -phenylethanol, 1-(p-methoxyphenyl)ethanol, n-pro- panol, isopropanol, 2-phenyl-2-propanol (cumene), n-butanol, isobutanol, sec.-butanol, tertbutanol, 1-phenyl-1 -chloroethane and 1,3- or 1 ,4-bis(1 -hydroxy-1 -methylethyl)benzene.

[0204] Special preference is given to water.

[0205] The polymerization can be conducted either continuously or batchwise. Continuous processes can be performed in analogy to known prior art processes for continuous polymerization of isobutene in the presence of Lewis Acid-donor complexes, preferably boron trifluoride-based catalysts in the liquid phase.

[0206] The process according to the invention is suitable either for performance at low temperatures, e.g. at -90°C to 0°C, or at higher temperatures, i.e. at at least 0°C, e.g. at 0°C to +30°C or at 0°C to +50°C. The polymerization in the process according to the invention is, however, preferably performed at relatively low temperatures, generally at -70°C to -10°C, especially at -60°C to -15°C.

[0207] Especially when a raffinate 1 stream is used as the isobutene source, the use of water as the sole initiator or as a further initiator has been found to be useful, in particular when polymerization is conducted at temperatures of -20°C to +30°C, especially of 0°C to +20°C. At temperatures of -20°C to +30°C, especially of 0°C to +20°C, when a raffinate 1 stream is used as the isobutene source, it is, however, also possible to dispense with the use of an initiator.

[0208] When the polymerization in the process according to the invention is conducted at or above the boiling temperature of the monomer or monomer mixture to be polymerized, it is preferably performed in pressure vessels, for example in autoclaves or in pressure reactors.

[0209] The polymerization in the process may be performed in the presence of an inert diluent. The inert diluent used should be suitable for reducing the increase in the viscosity of the reaction solution which generally occurs during the polymerization reaction to such an extent that the removal of the heat of reaction which evolves can be ensured. Suitable diluents are those solvents or solvent mixtures which are inert toward the reagents used. Suitable diluents are, for example, aliphatic hydrocarbons such as n-butane, iso butane, n-pentane, n-hexane, n- heptane, n-octane and isooctane, cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and the xylenes, and halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as methyl chloride, dichloromethane and trichloromethane (chloroform), 1,1 -dichloroethane, 1,2-dichloroethane, tri- 231664

[0210] 29 chloroethane and 1 -chlorobutane, and also halogenated aromatic hydrocarbons and alkylaromatics halogenated in the alkyl side chains, such as chlorobenzene, monofluoromethylbenzene, difluoromethylbenzene and trifluoromethylbenzene, and mixtures of the aforementioned diluents. The diluents used, or the constituents used in the solvent mixtures mentioned, are also the inert components of isobutenic C4 hydrocarbon streams. A non-halogenated solvent is preferred over the list of halogenated solvents.

[0211] The polymerization may be performed in a halogenated hydrocarbon, especially in a halogenated aliphatic hydrocarbon, or in a mixture of halogenated hydrocarbons, especially of halogenated aliphatic hydrocarbons, or in a mixture of at least one halogenated hydrocarbon, especially a halogenated aliphatic hydrocarbon, and at least one aliphatic, cycloaliphatic or aromatic hydrocarbon as an inert diluent, for example a mixture of dichloromethane and n-hexane, typically in a volume ratio of 10:90 to 90:10, especially of 50:50 to 85:15. Prior to use, the diluents are preferably freed of impurities such as water, carboxylic acids or mineral acids, for example by adsorption on solid adsorbents such as activated carbon, molecular sieves or ion exchangers.

[0212] In a preferred embodiment, the polymerization is performed in halogen-free aliphatic or especially halogen-free aromatic hydrocarbons, especially toluene. For this embodiment, water in combination with the organic hydroxyl compounds mentioned and / or the organic halogen compounds mentioned, or especially as the sole initiator, have been found to be particularly advantageous.

[0213] In another preferred embodiment, the polymerization is performed in halogen-free aliphatic or cycloaliphatic, preferably aliphatic hydrocarbons, especially n-butane, iso butane, hexane, pentane, heptane, cyclohexane, cyclopentane, and mixtures comprising them.

[0214] The polymerization is preferably performed under substantially aprotic and especially under substantially anhydrous reaction conditions. Substantially aprotic and substantially anhydrous reaction conditions are understood to mean that, respectively, the content of protic impurities and the water content in the reaction mixture are less than 50 ppm and especially less than 5 ppm. In general, the feedstocks will therefore be dried before use by physical and / or chemical measures. More particularly, it has been found to be useful to admix the aliphatic or cycloaliphatic hydrocarbons used as solvents, after customary prepurification and predrying with an organometallic compound, for example an organolithium, organomagnesium or organoalumi- num compound, in an amount which is sufficient to substantially remove the water traces from the solvent. The solvent thus treated is then preferably condensed directly into the reaction vessel. It is also possible to proceed in a similar manner with the monomers to be polymerized, 231664

[0215] 30 especially with isobutene or with the isobutenic mixtures. Drying with other customary desiccants such as molecular sieves or predried oxides such as aluminum oxide, silicon dioxide, calcium oxide or barium oxide is also suitable. The halogenated solvents for which drying with metals such as sodium or potassium or with metal alkyls is not an option are freed of water or water traces with desiccants suitable for that purpose, for example with calcium chloride, phosphorus pentoxide or molecular sieves. It is also possible in an analogous manner to dry those feedstocks for which treatment with metal alkyls is likewise not an option, for example vinylaro- matic compounds. Even if some or all of the initiator used is water, residual moisture should preferably be very substantially or completely removed from solvents and monomers by drying prior to reaction, in order to be able to use the water initiator in a controlled, specified amount, as a result of which greater process control and reproducibility of the results are obtained.

[0216] Step (c) - deactivation of the at least one Lewis acid

[0217] The polymerization reaction is appropriately terminated by adding and mixing the discharge from the polymerisation step (b) with excess amounts of water, alcohols or of basic material.

[0218] Examples for basic materials are gaseous or aqueous ammonia or aqueous (earth)alkali metal hydroxide solution such as sodium hydroxide-, potassium hydroxide-, magnesium hydroxide, or calcium hydroxide-solution, (earth)alkali metal carbonate- or (earth)alkali metal hydrogencar- bonate-solutions, such as sodium, potassium, magnesium or calcium hydrogencarbonate.

[0219] Preferred alcohols are Ci- to C4-alkanols, more preferably methanol, ethanol, iso-propanol, n- propanol or n-butanol.

[0220] Most preferred is water for terminating the polymerisation, especially distilled or deionized water.

[0221] The amount of water, alcohols or of basic material is for example the 0.1 to 2fold volume of the reaction mixture discharged from polymerisation step (b), preferably from 0.2 to 1.5, more preferably 0.25 to 1 , even more preferably the 0.25 to 0.75, and especially the 0.4 to 0.6fold volume.

[0222] The washing liquid is separated from the polymer-containing phase by phase separation. After unconverted C4 monomers and solvent - if any - have been removed, the crude polymerization product is typically washed repeatedly with distilled or deionized water, in order to remove adhering inorganic constituents or basic material.

[0223] It is also possible to use the reaction mixture from the polymerisation after desactivation of the catalyst and optionally after removal of the hydrolysis products by washing without further purification. Besides the polyisobutene composition such a reaction mixture may contain unreacted monomer and lower oligomers of isobutene.

[0224] In terms of process technology, all known extraction and washing processes and apparatus can be used for washing or extraction in step (c), e.g. those described in Ullmann's Encyclopedia of Industrial Chemistry, 6th ed, 1999 Electronic Release, Chapter: Liquid - Liquid Extraction - Apparatus. For example, these can be single- or multi-stage, preferably single-stage extractions, as well as those in direct or counter-current mode, preferably counter-current operation.

[0225] Preferably, sieve bottom or packed or packing columns, stirring tanks or mixer-settler devices, as well as pulsed columns or those with rotating internals are used.

[0226] The remaining organic phase may be directly fed into the subsequent step (d). It is also possible first to remove water, e.g. by absorption, as outlined below, and feed the remaining organic phase into step (d) thereafter.

[0227] In one embodiment it is preferred to separate remaining water or alcohol off the polymer- containing phase, since water resp. alcohol in the distillate may desactivate the Lewis acid in step (b).

[0228] Therefore, it may be advantageous to treat the polymer-containing phase with water- resp. alcohol-absorbing means, e.g. inorganic desiccants, such as silica gel, silicates, alumina, zeolites, diatomaceous earth, mixed aluminium / silicon oxides, as well as calcium carbonates and oxides, or molecular sieves.

[0229] Step (d) - distillation

[0230] After deactivation of the catalyst the solvent and unreacted monomers, dimers and trimers formed from the isobutene-containing monomer composition, and solvent in the reaction mixture are removed by way of distillation in step (d). Step (d) may comprise one or more distillation steps, e.g. one to three, preferably one or two, and more preferably one distillation step. 32

[0231] Single-stage distillation (flash distillation) can be done by passing through a suitable aggregate, such as rotary evaporator, thin film evaporator, falling film evaporator, wiper blade evaporator, sambay evaporator, etc., and combinations thereof.

[0232] Suitable circulation evaporators are known to those skilled in the art and are described, for example, in R. Billet, Verdampfertechnik [Evaporator Technology], HTB-Verlag, Bibliographisches Institut Mannheim, 1965, 53. Examples of circulation evaporators are tube bundle heat exchangers, plate heat exchangers, etc.

[0233] Preferably, a single step evaporation is sufficient without rectification equipment and can be conducted in a falling-film evaporator, a rising-film evaporator, a thin-film evaporator, a wiped- blade evaporator, a long-tube evaporator, a helical tube evaporator, a forced-circulation flash evaporator or a paddle dryer, for example a Discotherm® dryer from List Technology AG, Switzerland, or a combination of these apparatuses.

[0234] The distillation is conducted, as a rule, at 80 - 320°C, preferably 100 - 300°C, more preferably 120 - 280, even more preferably 140 - 260 °C, and 10 - 200 mbar, preferably 15 - 75, even more preferably 20 to 50 mbar.

[0235] Distillation may be assisted by leading an inert stripping through the evaporator, preferably nitrogen, argon, or oxygen-depleted air, i.e. air with low content of oxygen, e.g. not more than 10 vol%, preferably not more than 8, more preferably not more than 6, and even more preferably not more than 5 vol%.

[0236] If desired the distillation may take place in more than one distillation apparatus, e.g. two or three. In this case the distillation temperature may be increased from the first apparatus to the following and / or the pressure under which the distillation is conducted may be decreased.

[0237] In a preferred embodiment one distillation apparatus is sufficient.

[0238] Preferably, the single step distillation (d) is carried out as a flash evaporation in one or more apparatuses in which the reaction mixture stream undergoes a reduction in pressure by passing through a throttling valve or other throttling device. The reduction in pressure may happen once or several times, for example 1 to 5 times, preferably 1 to 3 times. 231664

[0239] 33

[0240] The pressure drop should be at least 2 bar, preferably at least 3 bar and particularly preferably at least 5 bar. More than 25 bar is usually not required, preferably not more than 20 bar.

[0241] For example, the pressure on the pressure side can be at least 2 bar, preferably at least 3 bar and particularly preferably at least 5 bar, and the pressure on the low-pressure side can be 10 - 200 mbar, preferably 15 - 75, even more preferably 20 to 50 mbar.

[0242] In case of a flash evaporation which is carried out in more than one apparatus, the starting pressure on the pressure side is reduced by at least one quarter, preferably at least one third of the starting value in each apparatus. The final flash evaporation should be conducted at a pressure of less than 200 mbar.

[0243] The temperature at which the polyisobutene containing high boiling stream is fed into the following apparatus is preferably at least the temperature of the previous apparatus or higher.

[0244] Such distillation and optionally stripping process yields a polyisobutene with a drastically reduced amount of solvent and monomer.

[0245] After distillation the content of isobutene remaining in the polyisobutene in the high boiling stream usually is not more than 1000 ppm by weight, preferably not more than 500, more preferably not more than 250, even more preferably not more than 100, especially not more than 50 and even not more than 25 ppm by weight.

[0246] By way of distillation the content of the solvent can be depleted, even if n-hexane is used as a solvent. Usually, the content of solvent, especially n-hexane, after distillation is not more than 2000 ppm by weight, preferably not more than 1500, more preferably not more than 1000, and especially not more than 750 ppm by weight. In a preferred embodiment, the amount of solvent is not more than 500, preferably not more than 250, more preferably not more than 100, even more preferably not more than 50 and especially not more than 25 ppm by weight.

[0247] The light boiling stream from the distillation (d) is preferably fed into the rectification step (e). More preferably this light boiling stream is fed into the rectification step (e) in gaseous form so that the distillation (d) acts as an evaporator for the rectification step (e).

[0248] Step (e) - rectification of the recycling stream 231664

[0249] 34

[0250] In rectification step (e) the light boiling distillate from step (d) is fed into at least one rectification column. Preferably the light boiling stream from step (d) is directly fed into at least one rectification column in gaseous form.

[0251] In step (e) the distillate from step (d) is separated into at least two streams,

[0252] - a light boiling fraction (e in which isobutene is enriched and dimers and trimers of isobutene are depleted, and

[0253] - a high boiling fraction (en) in which dimers and trimers of isobutene is enriched.

[0254] If solvent was used it usually is present in both fractions, preferably to a larger extent in the light boiling fraction (ei_). The fraction (e exhibits a lighter boiling range compared to the distillate stream from (d). In contrast, the fraction (en) has a higher boiling range than the distillate stream form (d).

[0255] Purification is carried out by rectification, optionally supported by stripping with an inert gas. This can also be done by increasing the temperature of the reaction mixture and / or lowering the pressure, preferably by a combination of these two measures.

[0256] Separation of the feed stream from step (d) into the light boiling fraction (e and the high boiling fraction (en) may take place in two or more, preferably two separate rectification columns, one for separating off the light boiling fraction (e and one for the high boiling fraction (en).

[0257] In a preferred embodiment, step (e) is carried out in a single rectification column into which the stream from step (d), e.g. in mixed gaseous and liquid, preferably in gaseous form, is fed in the middle section. The rectification column contains a stripping section below this influx and a rectification section (enriching section) above it. Preferably, the rectification section (enriching section) above the influx should contain at least 2, preferably at least 3, more preferably at least 4 theoretical separation plates and the stripping section of the rectification column below the influx should contain at least 4, preferably at least 6, and more preferably at least 8 theoretical separation plates.

[0258] Rectification columns can be equipped with internals, valves, side extractors, etc. if desired. The distillation column or columns used can be realised in a well-known design (see e.g. Sattler, Thermische Trennverfahren, 2nd edition 1995, Weinheim, pp. 135ff; Perry's Chemical Engineers Handbook, 7th ed. 1997, New York, Section 13). The distillation columns used may contain separating fixtures, such as separating floors, e.g. perforated bottoms, bell bottoms or valve 231664

[0259] 35 bottoms, structured packings, random packings or orderly packings, e.g. sheet or fabric packings, or irregular pouring of fillers.

[0260] Useful column internals are in principle all common internals, for example trays, structured packings and / or random packings. Of the trays, preference is given to bubble-cap trays, sieve trays, valve trays, Thormann trays and / or dual-flow trays; of the random packings, preference is given to those having rings, spirals, saddles or braids.

[0261] The condenser and the separation vessel are of conventional design.

[0262] The rectification is conducted, as a rule, at 80 - 320°C, preferably 100 - 300°C, and 2 - 20 bar, preferably 3 - 10 bar.

[0263] The rectification may further be supported by stripping with an inert gas.

[0264] The rectification in step (e) is conducted in such a way that the content of dimers and trimers of isobutene (in sum) in the combined streams, preferably in the recycling stream (e fed into the polymerisation (b) is not more than 20000 ppm by weight, preferably not more than 15000, and more preferably not more than 10000 ppm by weight. The content of dimers and trimers can even more preferably be reduced to not more than 7500, especially not more than 5000, and even not more than 4000 ppm by weight.

[0265] Since dimers and trimers of isobutene, especially diisobutenes are known to act as chain transfer agent, thus regulating the molecular weight of the polyisobutene it is preferable to maintain a certain level of diisobutene in the reaction mixture. Therefore, in a preferred embodiment of the present invention the recycling stream (e comprises at least 5 ppm by weight of dimers and trimers of isobutene (in sum), preferably at least 10, more preferably at least 15, even more preferably at least 25, especially at least 50, and even at least 100 ppm by weight of dimers and trimers of isobutene (in sum). Hence it is possible to keep the amount of dimers and trimers in the reaction mixture constant to regulate the molecular weight of the polyisobutene obtained.

[0266] As long as the aim of the polymerisation is not to produce a polyisobutene with a high content of internal double bonds (see below), it is preferred that the amount of dimers and trimers of isobutene (in sum) in the reaction mixture does not exceed 0.5 wt%, preferably not more than 0.4, more preferably not more than 0.3, even more preferably not more than 0.25, especially not more than 0.2, and even not more than 0.15 wt%. Accordingly, the content of dimers and tri- 231664

[0267] 36 mers in the recycling stream is adjusted to achieve an appropriate content in the reaction mixture.

[0268] Under the above-mentioned rectification conditions, the light boiling fraction (e predominantly consists of isobutene, diisobutenes, and solvent (if used in the reaction). Triisobutenes, tetraisobutenes, and even higher homologues of isobutene usually are present in traces only.

[0269] The high boiling fraction (en) predominantly consists of diisobutenes, triisobutenes, tetraisobutenes, and even higher homologues of isobutene, and solvent. Isobutene should be present in traces only. Rectifying the high boiling fraction (en) is especially preferred if a solvent is used in the polymerisation and should be recovered. In this case the high boiling fraction (en) is rectified into solvent and oligomers of isobutene and the solvent is fed into step (a) and / or (b).

[0270] If it is desired to obtain components of higher purity, the streams (e and / or (en) can be subjected to further rectification. This may be the case, for example, if the solvent is to be further purified or if one or more of the oligomers of isobutene are desired with higher purity.

[0271] For example, it is conceivable to accumulate diisobutenes and triisobutenes, preferably diisobutenes in order to produce a polyisobutene with a higher content of internal vinylidene double bonds (>C=CH2). Such polyisobutene is preferably obtainable by polymerising isobutene or an isobutene-containing monomer mixture in the presence of more than 0.5 wt% of a mixture comprising dimers and trimers of isobutene, preferably in the presence of at least 1.0 wt%, more preferably in the presence of at least 1.5 wt%, even more preferably in the presence of at least 2.0 wt%, particularly preferably in the presence of at least 2.5 wt%, and especially in the presence of at least 3 wt%.

[0272] Since the oligomers of isobutene are less reactive in polymerisation than monomeric isobutene, it is conceivable to use higher amounts of di- and triisobutene to obtain polyisobutene with an increased content of isomers with an internal vinylidene-double bond (>C=CH2), e.g. at least 4 wt%, preferably at least 5 wt%, more preferably at least 6, even more preferably at least 7.5, particularly preferably at least 10, and especially at least 15 wt%.

[0273] In order to achieve such high amounts of di- and triisobutenes, it may be necessary to feed these oligomers from external sources into the reaction mixture.

[0274] However, since the presence of less reactive di- and triisobutenes in the reaction mixture demands volume in the reactor, thus, decreasing the space-time-yield of the polymerisation, and further claims capacity in the distillative workup of the reaction mixture, the amounts of di- and 231664

[0275] 37 triisobutene in the reaction mixture should not exceed 50 wt%, preferably not more than 40, more preferably not more than 35, even more preferably not more than 30, particularly preferably not more than 25, and especially not more than 20 wt%.

[0276] With such a polymerisation it is possible to obtain a polyisobutene with an increased content of isomers with an internal vinylidene-double bond (>C=CH2) at the polymer backbone, selected from the group consisting of the isomers by polymerising an isobutene-containing monomer composition in the presence of at least one Lewis acid and optionally at least one solvent, compared to a polymerisation process of an isobutene-containing monomer composition under the same reaction conditions with the absence of dimers and trimers of isobutene.

[0277] It has furthermore been observed that the polyisobutene obtainable according to the present invention comprises polyisobutene isomers in which di- and triisobutene is polymerised into the backbone so that such polyisobutene bears one or more neopentyl- (2, 2-dimethyl-1 -propyl-) sidechains:

[0278] Such neopentyl-sidechains may be present in the polyisobutene additionally to the isomers (C6) and / or (C8) and / or (C9) or instead of these isomers. 231664

[0279] 38

[0280] The amount of each isomer is preferably determined with1H-NMR spectroscopy as described above.

[0281] As pointed out above, the reactivity of the different double bond isomers in polyisobutene depends on the molecular weight. Furthermore, due to the different manufacturing processes low and medium molecular polyisobutene usually exhibits a different distribution of double bond isomers, therefore, the content of isomers according to the invention may be different for polyisobutene of different molecular weight.

[0282] The amounts of isomers given throughout the text refer to mol%, unless explicitly stated otherwise. Since the determination of the individual or groups of isomers is conducted by NMR analysis (details see below) the result of such NMR analysis is a percental distribution of certain NMR signals of these isomers relative to the integral of the respective nucleus determined.

[0283] Step (f) - leading the rectified recycling stream (e into the polymerisation (b)

[0284] The light boiling fraction (e obtained from step (e) may optionally be further rectified, if desired, and is at least partially, preferably completely recycled into the polymerisation.

[0285] It is possible to directly introduce this stream into the polymerisation (b) or to mix the stream with the isobutene-containing monomer composition in step (a), e.g. in a static mixer or a mixing pump.

[0286] If a solvent is used in the polymerisation, it is a purpose of the recycling stream to recover unreacted isobutene and further to recycle the solvent and feed the thus recycled solvent into step (a) and / or (b).

[0287] If an isobutene-containing monomer composition, such as raffinate 1, is used in the polymerisation the recycling stream may further to isobutene, diisobutene, and solvent (if used) comprise other monomers, such as 1 -butene or 2-butene, or unreactive butane isomers.

[0288] It may be advantageous to first mix the recycled stream (e with fresh monomer feed (a) so that the isobutene concentration in the reaction mixture is kept constant, as it is known from WO 2013 / 104559.

[0289] Preferably, the process of polymerisation has a steady-state concentration of isobutene in the combined stream at the feed point of the combined stream into the reaction zone, i.e. preferably 231664

[0290] 39 an average value of 40 to 95% or 45 to 95% or 50 to 95% by weight, especially an average value of 40 to 80% or 45 to 80% or 50 to 80% by weight, in particular an average value of 40 to 65% or 45 to 65% or 50 to 65% by weight, more preferably an average value of 40 to 60% or 45 to 60% or 50 to 60% by weight, most preferably an average value of 40 to 55% or 45 to 55% or 50 to 55% by weight.

[0291] In a further preferred embodiment, the steady-state concentration of isobutene in the combined stream at the feed point of the combined stream into the reaction zone has a substantially constant value which may vary over the course of the polymerization reaction by a maximum of 10%, especially by a maximum of 8%, in particular by a maximum of 6%, more preferably by a maximum of 4%, most preferably by a maximum of 2%, in the upward or downward direction, based in each case on the mean isobutene concentration in the combined stream at the feed point.

[0292] It is known that such a process enables smoother operation of the isobutene polymerization from technical C4 hydrocarbon streams and ensures a homogeneous high content of terminal double bonds (vinylidene groups), a constant mean molecular weight, a homogeneous low consumption of polymerization catalyst and a low residual content of monomers and / or oligomers and of halogen in the polymer.

[0293] (g) - further workup of the polyisobutene-containing reaction mixture (optional)

[0294] Usually, residual monomers and solvent are separated from the polyisobutene mixture (high boiling stream from step (d)) by carrying out the distillation according to (d) in one or several steps.

[0295] In case it is required to have a further reduced content of solvent or monomers in the polyisobutene it may be advantageous to separate solvent or monomers off by an optional further distillation or preferably by using paddle dryers.

[0296] The polyisobutene mixture is treated at 100 - 320°C, preferably 120 - 300°C, and 0.1 - 40 mbar, preferably 0.5 - 20 mbar.

[0297] Such paddle dryers are, for example, Discotherm® dryers from List Technology AG, Switzerland. 231664

[0298] 40

[0299] Preferably the temperature of the polyisobutene increases during passage through the apparatus, preferably with a temperature gradient which changes by not more than 50°C during passage of the residue through the apparatus.

[0300] Such paddle dryers often have an essentially horizontal structure, transport of the residue is generally effected by means of one or two mixing and kneading shafts in the interior of the apparatus. In the specialist literature, these apparatuses are also referred to as particle bed reactors, kneading dryers or kneading reactors.

[0301] In a preferred embodiment, axial transport through the apparatus is effected by installation of transport, kneading and / or mixing elements, for example disc elements, shafts, screws, blades, wipers or rotors.

[0302] Heating is effected via the wall and can be effected in any way. Heating is preferably effected not only via the outer wall of the apparatus but also via the internals such as cleaning hooks, segmenting plates and kneading shafts.

[0303] A mechanical energy input into the apparatus of 5 W / kg or more is generally sufficient, preferably from 10 or more W / kg, particularly preferably 20 or more, very particularly preferably 40 or more, in particular 80 or more and especially 100 W / kg or more. In general, an energy input of more than 200 W / kg brings no advantages. The specific power input indicated here is the power introduced into the apparatus per amount of residue.

[0304] The thermal energy introduced into the residue via the wall is usually more than 120 kJ / kg of residue and less than 2400 kJ / kg of residue, preferably more than 220 kJ / kg of residue and less than 1800 kJ / kg of residue, particularly preferably more than 300 kJ / kg of residue and less than 1400 kJ / kg of residue and very particularly preferably more than 360 kJ / kg of residue and less than 900 kJ / kg of residue.

[0305] The heating section for the residue stream introduced into the paddle dryer preferably makes up more than 10% and less than 70% of the total length of the paddle dryer, preferably more than 20% and less than 60%, particularly preferably more than 30% and less than 50%, of the total length of the paddle dryer.

[0306] Such apparatuses are offered by, for example, List AG, Arisdorf, Switzerland, under the trade name Discotherm® B or List-CRP or AP and by Buss-SMS-Canzler GmbH, Butzbach, Germany under the names Reasol® or Reactotherm®. 231664

[0307] 41

[0308] As discharge devices for forced discharge of the polyisobutene depleted in monomer obtained after the monomers have been separated off, for example, screws, preferably twin screws.

[0309] Furthermore, the paddle dryer is preferably operated in conjunction with a vapor condenser by means of which the monomer which has been separated off can be recovered. Preferably the monomer which was separated off in this step is fed into the rectification (e) and recycled.

[0310] A preferred embodiment of the present process comprises filling the usable volume of the paddle dryer with residue to an extent of only 25-90%, preferably 30-80%, particularly preferably 40-75% and very particularly preferably 50-70%.

[0311] This is advantageous in that a certain degree of foaming of the residue in the apparatus is possible as a result of such incomplete filling.

[0312] The high-boiling stream from step (e) or (g), if it has passed through, is usually filled into the desired containers or packaged directly and then stored.

[0313] The NMR spectroscopy of the polyisobutene polymers was performed as described in Guo et al., Journal or Polymer Science, Part A: Polymer Chemistry, 2013, 51 , 4200-4212, on a Bruker 700 MHz spectrometer using 5 mm o.d. tubes with appropriate concentration of polyisobutene in deuterated chloroform (CDCh) as a solvent at 25 °C. The1H spectra (400 MHz) of polyisobutene solutions in CDCh were calibrated to tetramethylsilane as internal standard (bH= 0.00) or to the solvent signal (be = 77.0), respectively. The distortionless enhancement by polarization transfer (DEPT) technique was further used for structural characterization of polyisobutenes.

[0314] Isomer (C6) can easily be identified in1H NMR spectra due to it signal at approx. 4.80 ppm, isomer (C7) shows a signal at approx. 5.11 ppm, and the neopentyl sidechains show signals at approx. 0.90, 1.75, 1.83, 1.90, and 1.94 ppm. 231664

[0315] 42

[0316] Percentages in this document refer to percentages by weight, unless expressly stated otherwise.

[0317] The examples which follow are intended to illustrate the present invention in detail without restricting it.

[0318] Examples

[0319] Analytical methods

[0320] Unless explicitly mentioned otherwise analysis according to this invention was carried out as follows:

[0321] Gaschromatography (GO

[0322] Gaschromatography was performed in a Varian 450-GC with split injector (1 : 75 at 250 °C) and flame ionisation detector (300 °C, range 12) with a column Sil5 CB 25 m x 0.15 mm id; film thickness 1.2 pm.

[0323] As carrier gas hydrogen was used in a flow rate 0.7 ml / min.

[0324] Temperature program: 1 min at 60 °C, heat up with 10 °C / min up to 90 °C and then 30 °C / min until 250 °C is reached, keep 10 min at 250 °C. n-Nonane was used as internal standard.

[0325] Gel Permeation Chromatography (GPQ

[0326] Gel Permeation Chromatography (often referred to as Size exclusion chromatography (SEC)) was performed on an Ultimate 3000 Thermo Scientific apparatus with two Agilent PLgel 3pm MIXED-E (300x7.5 mm) columns thermostated at 35 °C. The detection was achieved by differential refractometer (Rl, Agilent G1362A RID) as well as diode array detector (UV, Agilent G1314A VWD at 254 nm). Tetrahydrofuran (THF) stabilised with 250 ppm 4-tert. butyl hydroxy toluene (BHT) was eluted at a flow rate of 1.0 mL / min. The calculation of molecular weight and polydispersity D was carried out using polystyrene standards (162 - 51950 g / mol, determined separately). Recommended polymer concentration: 2.5 g / l.

[0327] The results were interpreted manually using the software PSS WinGPC.

[0328] General preparation method

[0329] A stirred vessel with 60 ml volume was continuously fed with 144 g / h isobutene, 120 g / h hexane and a complex BF3 and methanol (molar ratio 1 : 1) at minus 20 °C. After the reaction mixture in the reactor has reached eguilibrium (usually after 2 to 3 hours), a sample was taken in order to analyse the reaction mixture for the polymerisation of pure isobutene under the present reaction conditions. Hereafter, a mixture of diisobutene isomers was continuously metered into the reac- 231664

[0330] 43 tion mixture at the flow rate given in the examples and further samples were taken after approx.

[0331] 2 and 4 hours.

[0332] The complex BF3 and methanol was metered into the reaction mixture so that the conversion of isobutene (measured by IR spectroscopy) was kept constant.

[0333] In the samples BF3 was desactivated with isopropanol and analysed by1H-NMR spectroscopy.

[0334] Example 1

[0335] 0.72 g / h diisobutene (DIB, 0.5 wt%) were metered into the reaction mixture. The conversion was kept at approx. 83 + / - 1%.

[0336] Tetra: Sum of all tetra-substituted isomers

[0337] Conversion: Determined by IR analysis

[0338] Mn: Determined by gel permeation chromatography (GPC)

[0339] It can easily be seen that an amount of 0.5 wt% diisobutene leaves the molecular weight of polyisobutene reaction mixture nearly unchanged, while the amount of isomers with internal vinylidene double bonds and tetra-substituted double bonds increases at the expense of isomers containing an alpha-double bond.

[0340] Analysis of the polymer mixture by GPC shows a monomodal distribution of molecular weight.

[0341] Example 2

[0342] 7.2 g / h diisobutene (DIB, 5.0 wt%) were metered into the reaction mixture. The conversion was kept at approx. 82 + / - 1%. 231664

[0343] 44

[0344] It can easily be seen that higher amounts of diisobutene yield higher amounts of isomers with internal vinylidene double bonds and tetra-substituted double bonds at the expense of isomers containing an alpha-double bond. The content of tri-substituted double bonds also increases, presumably due to formation of isomer (C7). The molecular weight decreases.

[0345] Analysis of the polymer mixture by GPC shows a monomodal distribution of molecular weight.

[0346] Example 3 - Distillation of hexane / isobutene / oligomer stream

[0347] A feed stream distilled off a polyisobutene reaction mixture from the polymerisation of isobutene in hexane as solvent with a composition as given in the table below was fed into a rectification column equipped with single path valve trays (caged valves) TH7 from Koch-Glitsch LP with 11 (practical) trays above the feed and 14 trays in the lower section.

[0348] Composition of the bottom and top streams of the rectification column were analysed (wt%):

[0349] It can easily be seen that rectification effectively reduces the amount of diisobutene in the light boiling stream which can directly be led into the polymerisation. Higher oligomers are essentially absent in the light boiling stream.

Claims

23166445Claims1. Process for polymerisation of isobutene-containing monomer compositions yielding polyisobutene comprising at least the steps of(a) providing an isobutene-containing monomer composition and optionally at least one solvent,(b) polymerisation of the isobutene-containing monomer composition in the presence of at least one halide of boron, aluminium, iron, gallium, titanium, zinc or tin as Lewis acid forming a reaction mixture comprising lower oligomers of isobutene, especially dimers and trimers, polyisobutene, and unreacted isobutene,(c) stopping the polymerisation by deactivating the at least one Lewis acid,(d) distilling off unreacted- isobutene-containing monomer composition,- dimers and trimers formed from the isobutene-containing monomer composition, and- optionally solvent in one or more distillation steps from the reaction mixture obtained from step (c) forming a recycling stream,(e) rectifying the recycling stream of step (d), thereby separating the recycling stream at least in- a fraction (eL) in which isobutene is enriched and- a fraction (eH) in which dimers and trimers of isobutene is enriched,(f) leading the rectified recycling stream (eL) obtained from step (e) at least partly into the polymerisation (b), wherein the content of dimers and trimers (in sum) in the combined streams fed into the polymerisation (b) is not more than 20000 ppm by weight, preferably not more than 15000, and more preferably not more than 10000 ppm by weight, wherein the isobutene-containing monomer composition in step (a) is pure isobutene or an isobutene-containing C4 hydrocarbon stream comprising less than 500 ppm of butadiene and optionally 1 -butene, cis- and trans-2-butene.

2. Process according to Claim 1 , wherein the Lewis acid in step (b) is selected from the group consisting of boron halides, aluminium halides, alkyl aluminium dihalides, dialkyl aluminium halides,23166446 iron halides, titanium halides, tin halides, and zinc halides.

3. Process according to Claim 1 or 2, wherein the Lewis acid in step (b) is utilised as a complex with a Lewis base as a donor.

4. Process according to Claim 3, wherein the Lewis base is selected from the group consisting of- dialkyl ethers- at least one halide bearing dialkyl ethers,- carboxylic acid alkyl esters- ketones,- aldehydes, and- alkanols.

5. Process according to any one of the preceding claims, wherein the dimers and trimers formed from the isobutene-containing monomer composition are selected from the group consisting of- alpha-diisobutene,- beta-diisobutene,- alpha-triisobutene, and- beta-triisobutene.

6. Process according to any one of the preceding claims, wherein the isobutene- containing monomer composition in step (a) is raffinate 1.

7. Process according to any one of the Claims 1 to 5, wherein the isobutene-containing monomer composition in step (a) is isobutene with a content of isobutene of at least 95 wt%.

8. Process according to any one of the preceding claims, wherein step (d) is conducted as at least one flash evaporation.

9. Process according to any one of the claims 1 to 7, wherein step (d) is conducted in at least one rotary evaporator, thin film evaporator, falling film evaporator, wiper blade23166447 evaporator, sambay evaporator, and combinations thereof.

10. Process according to any one of the preceding claims, wherein in step (e) the fraction (eL) is rectified over at least 2 theoretical separation plates.

11. Process according to any one of the preceding claims, wherein in step (e) the fraction (eH) is rectified over at least 4 theoretical separation plates.

12. Process according to any one of the preceding claims, wherein the rectification in step (e) is conducted at a temperature of from 80 to 320°C, preferably from 100 to 300°C.

13. Process according to any one of the preceding claims, wherein the rectification in step (e) is conducted at a pressure of from 2 to 20 bar, preferably from 3 to 10 bar.

14. Process according to any one of the preceding claims, wherein in step (e) the fraction (eL) comprises at least 5 ppm by weight of dimers and trimers of isobutene (in sum), preferably at least 10, more preferably at least 15, even more preferably at least 25, especially at least 50, and even at least 100 ppm by weight of dimers and trimers of isobutene (in sum).

15. Process for preparation of polyisobutene with an increased content of isomers with an internal vinylidene-double bond (>C=CH2) at the polymer backbone selected from the group consisting of the isomersby polymerisation of isobutene-containing monomer compositions yielding polyisobutene comprising at least the steps of23166448(a) providing an isobutene-containing monomer composition and optionally at least one solvent,(b) polymerisation of the isobutene-containing monomer composition in the presence of at least one halide of boron, aluminium, iron, gallium, titanium, zinc or tin as Lewis acid forming a reaction mixture of lower oligomers of isobutene, especially dimers and trimers, polyisobutene, and unreacted isobutene,(c) stopping the polymerisation by deactivating the at least one Lewis acid,(d) distilling off unreacted- isobutene-containing monomer composition,- dimers and trimers formed from the isobutene-containing monomer composition, and- optionally solvent in one or more distillation steps from the reaction mixture obtained from step (c) forming a recycling stream,(e) rectifying the recycling stream of step (d), thereby separating the recycling stream at least in- a fraction (eL) in which isobutene is enriched and- a fraction (eH) in which dimers and trimers of isobutene is enriched,(f) leading the rectified recycling stream (eL) obtained from step (e) at least partly into the polymerisation (b), wherein the content of dimers and trimers (in sum) in the recycling stream fed into the polymerisation (b) is more than 2.0 wt%, more preferably at least 2.5, even more preferably at least 3.0, especially at least 3.5, and even at least 4.0 wt%, wherein the content of isomers with an internal vinylidene-double bond (>C=CH2) at the polymer backbone is increased compared to a polymerisation process of an isobutene-containing monomer composition under the same reaction conditions with the absence of dimers and trimers of isobutene.

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