Process for providing stream comprising high proportion of 2, 4, 4-trimethylpent-1-ene

Abstract

The present invention relates to a process for providing a stream comprising a high proportion of 2, 4, 4-trimethylpent-1-ene. The subject of the invention is to provide a process for an overhead stream K containing more than 85% by weight of 2, 4, 4-trimethylpent-1-ene, in which both the isomerization of 2, 4, 4-trimethylpent-2-ene to 2, 4, 4-trimethylpent-1-ene and the distillation are carried out in order to obtain the overhead stream K. The isomerization is at least partially fed to the bottom stream of the distillation in which an overhead stream K is removed from the overhead.

Description

Technical Field

[0001] The present invention relates to a process for providing a top stream K comprising more than 85% by weight of 2,4,4-trimethylpent-1-ene, wherein both an isomerization of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene and a distillation are carried out to obtain the top stream K. The isomerization is at least partly fed with the bottom stream of the distillation in which the top stream K is taken off overhead. Background Art

[0002] Diisobutene is an industrially relevant product obtained by dimerization of isobutene. Diisobutene consists of the isomers 2,4,4-trimethylpent-1-ene (hereinafter also referred to as: TMP1) and 2,4,4-trimethylpent-2-ene (hereinafter also referred to as: TMP2), wherein the mass distribution of TMP1:TMP2 is about 78:22 to 81:19 (equilibrium distribution). This mixture can be converted into more valuable products in carbonylation processes in particular. In carbonylation processes in particular, such as methoxycarbonylation (the reaction product here is 3,5,5-trimethylhexanoic acid methyl ester) or hydroformylation (the reaction product here is 3,5,5-trimethylhexanal), the internal olefin TMP2 exhibits a significantly lower reactivity than the terminal olefin TMP1. Due to insufficient stability of the catalyst or economic factors (e.g. the size of the reactor), it is usually impossible to fully adjust the reaction conditions or residence time in these carbonylation reactions so that the terminal TMP2 reacts completely.

[0003] Direct use of unreacted TMP2 is disadvantageous for reasons of reactivity. It is therefore proposed to convert TMP2 or a portion thereof into the more reactive form TMP1 by isomerization, which can ultimately be converted into valuable products.

[0004] Processes for the isomerization of TMP2 to TMP1 are known in the literature. However, these processes are carried out under homogeneous catalysis and are based on strong mineral acids, such as H 2 SO4、H 3 PO 4 Or benzenesulfonic acid (see US2,554,251 A). However, homogeneous catalytic reaction systems have the disadvantage that the isomerization catalyst must be separated again in an expensive manner from the obtained pure TMP1 or the obtained TMP1 / TMP2 mixture. Only in this way can they be supplied to the above-mentioned carbonylation process. In addition, acidic systems are usually also corrosive, so high-quality materials are required.

[0005] A further problem is that, depending on the downstream process steps, for example the carbonylation process, the proportion of TMP1 in the product stream of the isomerization may still be too low to achieve favourable results in the respective downstream process steps. Summary of the invention

[0006] It is therefore an object of the present invention to provide a process for the isomerization of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene which does not exhibit the above-mentioned problems. The process should continuously provide a stream comprising a high proportion of 2,4,4-trimethylpent-1-ene. The process should simultaneously provide the possibility of further converting 2,4,4-trimethylpent-2-ene into 2,4,4-trimethylpent-1-ene.

[0007] This object is achieved by the method according to the invention according to independent claim 1. Preferred embodiments are described in the dependent claims.

[0008] According to the invention, the process is a process for providing a top stream K containing more than 85% by weight of 2,4,4-trimethylpent-1-ene, preferably more than 90% by weight of 2,4,4-trimethylpent-1-ene, particularly preferably more than 95% by weight of 2,4,4-trimethylpent-1-ene, wherein the process comprises at least the following steps:

[0009] a. supplying a stream A comprising 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene to a distillation unit and separating said stream A into at least a top stream K which is enriched in 2,4,4-trimethylpent-1-ene relative to stream A and contains more than 85% by weight of 2,4,4-trimethylpent-1-ene, preferably more than 90% by weight of 2,4,4-trimethylpent-1-ene, particularly preferably more than 95% by weight of 2,4,4-trimethylpent-1-ene, and a stream B which is depleted in 2,4,4-trimethylpent-1-ene relative to stream A;

[0010] b. isomerizing stream B to 2,4,4-trimethylpent-2-ene using a heterogeneous catalyst based on zeolites or ion exchange resins to obtain an isomerized product stream in which the proportion of 2,4,4-trimethylpent-2-ene is lower and the proportion of 2,4,4-trimethylpent-1-ene is higher than in stream B;

[0011] The product stream of the isomerization is sent at least partly as stream A to distillation, and wherein

[0012] The input stream for feeding the process and containing 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene is sent, besides stream A, to the distillation unit in step a. and / or, besides stream B, to the isomerization in step b.

[0013] The advantage of the process according to the invention is the use of a heterogeneous catalyst system. Such a catalyst system does not need to be separated from the product stream, but remains in the reaction vessel or reactor. The zeolite-based or ion exchange resin-based catalyst system according to the invention also enables high conversion rates to be achieved.

[0014] A further advantage of the process is the distillation arranged downstream of the isomerization, whereby the proportion of 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene in the top stream K of the at least one distillation column can be further increased relative to the streams used. It is thus possible to achieve a proportion of 2,4,4-trimethylpent-1-ene in this stream of more than 85% by weight, preferably more than 90% by weight, particularly preferably more than 95% by weight, which is advantageous for downstream process steps, for example the carbonylation process.

[0015] A further advantage is the flexible supply of the input mixture. Thus, the process according to the invention can be adapted to the respective situation, for example depending on the input stream used. If the ratio of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene in the input stream is close to the equilibrium distribution, this stream can initially be sent to a distillation. If the ratio of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene in the input stream deviates from the equilibrium distribution, this stream can initially be sent to an isomerization. It can thus be more easily incorporated into existing production plants, depending on the composition of the input stream.

[0016] Step a. of the process according to the invention involves the distillation of a stream A comprising 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene. Stream A is separated into at least a top stream K which is enriched in 2,4,4-trimethylpent-1-ene relative to stream A and contains more than 85% by weight of 2,4,4-trimethylpent-1-ene, preferably more than 90% by weight of 2,4,4-trimethylpent-1-ene, particularly preferably more than 95% by weight of 2,4,4-trimethylpent-1-ene, and a stream B which is depleted in 2,4,4-trimethylpent-1-ene relative to stream A.

[0017] According to the invention, the stream A fed to the distillation originates from the isomerization. The stream obtained as a product stream in the isomerization is fed to the distillation at least partially or completely as stream A. According to the invention, it is possible to feed, in addition to stream A, an input stream which is fed to the process and contains 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene to the distillation unit in step a. It is also possible to feed this input stream to the isomerization in step b. or to feed this input stream both to the distillation in step a. and to the isomerization in step b.

[0018] The input stream to be used contains 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene. Such a stream may be a diisobutene stream, which can be prepared from isobutene or an isobutene-containing hydrocarbon mixture by dimerization, as disclosed, for example, in EP 1 360 160 B1. Furthermore, the stream to be used here may be obtained as an unreacted residual stream in a carbonylation process, for example in methoxycarbonylation or in hydroformylation.

[0019] It has already been mentioned that the input stream can be supplied to the isomerization and / or the distillation. The designation of steps a. and b. in the claims therefore does not constitute a priority or chronological order. It is obvious that both steps must be carried out and that each step is fed by the respective other step. Therefore, which step is considered to be carried out first is of secondary importance.

[0020] The distillation in step a. of the process according to the invention is carried out in at least one distillation unit. Corresponding units are known in principle to the person skilled in the art. The distillation unit according to the invention preferably comprises at least one distillation column, more preferably at least two distillation columns. As long as more than one distillation column is present in the distillation unit, the following description of the characteristics of the distillation column always also applies.

[0021] The distillation column preferably comprises internals to achieve the separation task. Suitable internals are familiar to the person skilled in the art. Particularly suitable here are random or structured packings, such as those known to the person skilled in the art under the trade names such as In a preferred embodiment of the present invention, the at least one distillation column comprises at least 50 theoretical plates, preferably at least 70 theoretical plates, more preferably at least 90 theoretical plates. If two or more distillation columns are present, these distillation columns may have the same or different numbers of theoretical plates.

[0022] The operating parameters of the distillation column are guided by the separation task and the design of the distillation column. It is preferred in the present process that the at least one distillation column is operated under reduced pressure, particularly preferably at a pressure of 0.2 to 0.9 bar. In the context of the present invention, reduced pressure is always present as long as operation is carried out at an ambient pressure below about 1 bar (i.e. the atmospheric pressure prevailing at the respective location). If two or more distillation columns are present, these can be operated at the same or different pressures.

[0023] It is further preferred that the bottom temperature of the at least one distillation column is from 50 to 100° C. If two or more distillation columns are present, these can be operated at the same or different temperatures.

[0024] Another parameter for the design of a distillation column is the reflux ratio. The reflux ratio refers to the ratio of reflux (recycle) to distillate (drawn condensate, in this case therefore the top stream K). The reflux is thus the condensed part of the top stream which is returned to the distillation column. It is preferred according to the invention that the reflux ratio of the at least one distillation column in the distillation in step a. is from 5 to 15.

[0025] By the distillation according to the invention in step a, a top stream K is produced in the at least one distillation column which contains at least 85% by weight of 2,4,4-trimethylpent-1-ene, preferably at least 90% by weight of 2,4,4-trimethylpent-1-ene, preferably at least 95% by weight of 2,4,4-trimethylpent-1-ene. The distillation further produces a stream B which is depleted in 2,4,4-trimethylpent-1-ene relative to stream A.

[0026] The stream B additionally produced in the distillation in step a. can be withdrawn from the at least one distillation column as a bottom stream or as a side stream. If two distillation columns are present, stream B is produced in the last distillation column, regardless of whether it is withdrawn as a side stream or as a bottom stream. If stream B is withdrawn as a side stream, it can in principle be arranged at the same height as the inlet of stream A or below the inlet of stream A. It is obvious here that the inflow and outflow must be arranged at a sufficient distance apart. Whether withdrawn as a side stream or as a bottom stream, stream B preferably contains 80% to 92% by weight of 2,4,4-trimethylpent-2-ene.

[0027] If stream B is withdrawn as a bottom stream of the at least one distillation column in the distillation in step a, a purge stream containing high boilers formed during the isomerization, for example dimers or oligomers of 2,4,4-trimethylpent-2-ene and / or 2,4,4-trimethylpent-1-ene, is preferably withdrawn from stream B before or after the isomerization. The separated high boilers can be incinerated to generate energy or can be hydrogenated to prepare valuable alkanes therefrom.

[0028] If stream B is withdrawn as a side stream from the at least one distillation column in the distillation in step a, a stream containing high boilers formed during the isomerization, for example dimers or oligomers of 2,4,4-trimethylpent-2-ene and / or 2,4,4-trimethylpent-1-ene, is preferably produced at the bottom of the at least one distillation column. The separated high boilers can be incinerated to generate energy or can be hydrogenated to prepare valuable alkanes therefrom.

[0029] As is known, the distillation column is heated at the bottom to perform the separation task. The energy can be supplied here by means of heating steam which is usually available at chemical production sites. For this purpose, a portion of the bottom product is passed through a heat exchanger (bottom evaporator), where it is heated and then returned to the bottom of the distillation column. In order to reduce the energy requirement and / or CO 2 Discharge, heat integration can be provided in the distillation in step a. Heat integration means that the energy generated or present in the process is used elsewhere. In the present case, the condensation energy generated (released) at the top of at least one distillation column of the distillation unit is particularly suitable. In a preferred embodiment of the invention, heat integration is therefore carried out in step a. so that at least part of the condensation energy at the top of the column is used to heat the bottom product.

[0030] Another possibility for heat integration is so-called vapor compression, in which at least part of the vapor (top stream) is compressed, i.e. brought to a higher pressure level and optionally heated. The vapor thus compressed and optionally heated is supplied to a heat exchanger (bottom evaporator) to heat the bottom product. This utilizes the heat of condensation of the vapor.

[0031] Another possibility is to use a heat pump. The heat pump is operated with a working medium, such as n-butane or water. The condensation energy is therefore first transferred to the working medium in a heat exchanger in this case, and from there to the distilled bottom product in another suitable heat exchanger. The working medium is usually conveyed to the heat exchanger at the bottom of the tower via a compressor. In principle, a two-stage or multi-stage heat pump can also be used in which there is more than one compressor stage. In the case of a two-stage heat pump, there are not only one working medium, but two working media, wherein the energy exchange between the first and second working media also takes place in the heat exchanger. In the case of a multi-stage configuration, there are correspondingly more working media.

[0032] The isomerization in step b. is carried out with stream B which is depleted in 2,4,4-trimethylpent-1-ene relative to stream A and is taken off from the distillation in step a. In addition to stream B, it is also possible to send input streams partly or completely to the isomerization.

[0033] Isomerization can also be carried out in principle in various suitable reactors. Isomerization can be carried out in a single reactor or in a plurality of reactors connected in parallel or in series. It can also be carried out in batches or continuously. Isomerization is preferably carried out in one or more continuously operated reactors conventionally used in solid / liquid contact reactions. When a continuously operated flow reactor is used, a fixed bed is usually but not exclusively used. When a fixed bed flow reactor is used, the liquid can flow upward or downward. Generally, it is preferred that the liquid flows downward. In addition, the reactor can be operated under product recirculation or in a straight-through manner. For example, a reactor in which an ion exchanger or a zeolite is present in the form of suspension in the liquid phase is a concept different from a fixed bed reactor.

[0034] The reactor used in the isomerization according to the invention is preferably a tubular reactor or a tube bundle reactor, in particular one having an internal tube diameter of 10 to 60 mm. The length-to-diameter ratio of the catalyst bed can be varied here by means of the geometric dimensions of the reactor or by means of its filling level. With the same contact quantity and load (LHSV), different empty tube velocities can thereby be achieved and the heat transfer to the cooling medium can be influenced in a targeted manner.

[0035] The cooling of the tubes of the reactor (whether it is a tubular reactor or a tube bundle reactor) can be achieved by means of a cooling medium (such as cooling water or an endothermic process fluid for heat integration) via a heat exchanger in the jacket space of the reactor or an external recirculation system. Especially when a liquid heating medium is used, the jacket side is constructed so that there is a temperature gradient as uniform as possible at all tubes. The technical measures required for this are known to those skilled in the art and are described in the literature (installing a deflector plate, a disc-ring structure, the input / output of a heat carrier, etc. at different positions in the reactor). Preferably, the reaction medium and the heat carrier are transported through the reactor tube or the reactor jacket in a co-current manner, more preferably from top to bottom. Preferred embodiments are described in, for example, DE 102006040433A1.

[0036] The isomerization of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene occurs exothermically, ie with release of energy, which leads to an increase in the temperature of the reaction mixture. In order to limit the temperature increase, the input stream can be diluted, for example by recycling the product.

[0037] The one or more reactors used in the isomerization can be operated adiabatically, polytropically or virtually isothermally. Virtually isothermal means that the temperature at any point in the reactor is at most 10° C. higher than the temperature at the reactor inlet. In the case of adiabatic operation of the reactor, it is generally advantageous to arrange a plurality of reactors in series and to provide cooling between the reactors. Reactors suitable for polytropic or virtually isothermal operation are, for example, the already mentioned tube bundle reactors as well as stirred tank reactors and loop reactors.

[0038] The process can be carried out at relatively mild temperatures. The isomerization in step b is preferably carried out at a temperature of 25°C to 90°C, preferably 30°C to 80°C, particularly preferably 35°C to 70°C.

[0039] Furthermore, the isomerization according to the invention can be carried out at a pressure which is equal to or greater than the vapor pressure of the input stream mixture and / or the reaction mixture at the respective reaction temperature, preferably at a pressure greater than 0 bar but less than 40 bar.

[0040] The isomerization in step b. is also preferably carried out in the liquid phase. It should be clear that in this case, the pressure and temperature must be selected so that the input stream is present in the liquid phase or can be present in the liquid phase.

[0041] The isomerization according to the invention may also use different catalysts based on zeolites or ion exchange resins in the one or more reactors. For example, a mixture of ion exchange resins of different reactivity may be used. The reactors may also contain catalysts of different activities, for example arranged in layers. If more than one reactor is used, each reactor may be filled with the same or different zeolite-based or ion exchange resin-based catalyst(s).

[0042] The isomerization according to the invention uses a catalyst based on a zeolite or an ion exchange resin as a heterogeneous catalyst. The corresponding zeolites and ion exchange resins are widely available and known to those skilled in the art. It has been found that the catalyst based on zeolites preferably has a Si:Al ratio of 40:1 to 200:1. In the case of catalysts based on ion exchange resins, it has also been found that the H-type and the partially neutralized form of styrene-divinylbenzene types are preferably very suitable.

[0043] When the catalyst is a zeolite, some zeolites have proven to be particularly advantageous, such as β- and γ-zeolites. The zeolite is therefore preferably selected from Z-β-H-25, Z-β-H-38, Z-β-H-360, Z-Mor-H-20, ZYH-60, ZYH-80, Z-β-H, Z-CFG-1, Z-β-ammonium-38, Z-CBV 760CY (1.6), Z-CBV 780CY (1.6), CP 814E CY (1.6), CBV 500CY (1.6), H-CZB-150 and mixtures thereof.

[0044] The ion exchange resin used can be, for example, an ion exchange resin made by sulfonation of a phenol / aldehyde condensate or by sulfonation of a copolymer of an aromatic vinyl compound. Examples of aromatic vinyl compounds used to produce the copolymer are: styrene, vinyl toluene, vinyl naphthalene, vinyl ethylbenzene, methyl styrene, vinyl chlorobenzene, vinyl xylene and divinylbenzene. Particularly preferably, an ion exchange resin made by sulfonation of a copolymer formed by the reaction of styrene with divinylbenzene isomerized. The ion exchange resin can be produced in a gel-like, macroporous or sponge-like form. The properties of these resins, in particular the specific surface area, porosity, stability, swelling or shrinkage and exchange capacity can be varied as known by the production method.

[0045] Preferred ion exchange resins of the styrene-divinylbenzene type are sold, inter alia, under the trade names CT 151 and CT 275 from Purolite, CT 151 from Rohm & Haas, CT 275 ... 15. 35. IR-120, 200, Dowex M-31 from Dow, Lanxess K2621, K-2431.

[0046] The pore volume of the ion exchange resins which can be used as catalysts, in particular those of the preferred styrene-divinylbenzene type, is preferably from 0.3 to 0.9 ml / g, more preferably from 0.5 to 0.9 ml / g. The pore volume can be determined, for example, by adsorption techniques. The particle size of the ion exchange resin is preferably from 0.3 mm to 1.5 mm, more preferably from 0.5 mm to 1.0 mm. Narrower or wider particle size distributions can be selected. Thus, for example, ion exchange resins with very uniform particle sizes (monodisperse resins) can be used.

[0047] The ion exchange resins which can be used as catalysts for the isomerization can be present as partially neutralized ion exchange resins. For this purpose, the ion exchange resins can be treated with acids or bases as described in EP 1360160 B1.

[0048] The isomerization in step b. subsequently results in a product stream having a lower proportion of 2,4,4-trimethylpent-2-ene and a higher proportion of 2,4,4-trimethylpent-1-ene than in the stream B used. The product stream from the isomerization is then partly or completely sent to the distillation in step a. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Refer to the attached pictures Figure 2 , Figure 3 and Figure 4 The present invention is explained in more detail. Figure 1 The flow chart on which the simulation in Example 2 is based is shown and explained in the experimental description.

[0051] Figure 2 An embodiment is shown in which stream B is withdrawn from the distillation (1) as a bottom stream. Stream B is then fed to the isomerization (3). The product stream obtained here is fed to the distillation (1). In the case of the formation of high boilers, a purge stream (5) can be withdrawn before or after the isomerization (3). This is indicated by the dashed line. It is more advantageous to separate off the high boilers before the isomerization. An input stream (7) is also fed to the distillation (1) and / or the isomerization (3). The desired top stream K (6) is then withdrawn from the distillation.

[0052] Figure 3 An embodiment is shown in which stream B is withdrawn from distillation (1) as a side stream. In this embodiment, any high boilers that may be produced will be produced as purge (5) at the bottom of distillation (1). Everything else is the same as in the embodiment according to Figure 2 The implementation scheme is the same.

[0053] Figure 4 show Figure 2 and 3 , wherein, unlike these embodiments, there is a vapor compression. Here, the vapor is sent to the bottom product via a compressor (8) and the energy is transferred to the bottom product in a heat exchanger. The vapor (6) is condensed and discharged from the process as a fraction enriched in TMP-1. In the case of stream B, Figure 2 and 3 The possibility of withdrawing this stream from the distillation described in is indicated by a dashed line. DETAILED DESCRIPTION

[0054] The invention is described below with reference to examples. These are for illustrative purposes and do not limit the subject matter of the invention.

[0055] Example

[0056] Example 1

[0057] 2.4 g of the catalyst according to the invention (Purolite CT 275, partially neutralized, 0.9 eq / L) were weighed into a tubular reactor having a diameter of 0.6 cm and a height of 12 cm. This resulted in an empty tube volume of 3.39 cm 3 . 2,4,4-trimethylpent-2-ene (>99%) was supplied to the reactor at a supply rate of 0.1 g / min. This resulted in an empty tube residence time of 24.5 minutes. The isomerization was carried out at a temperature of 55° C. and ambient pressure. After leaving the reactor, the distribution of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene was determined (99:1 2,4,4-trimethylpent-2-ene:2,4,4-trimethylpent-1-ene in the input stream) as shown in Table 1. The analysis was carried out by gas chromatography. The peak areas were evaluated by an external calibration method.

[0058] Table 1: Isomer ratios in diisobutylene

[0059]

[0060] a After 80 hours of experiment time

[0061] The results show that the catalyst according to the invention is very suitable for isomerization.

[0062] Example 2

[0063] Material data available within Evonik were used for the simulations. Aspen Plus version V10 was used as the simulation tool. The isomerization reactor was specified according to the experimental data from Example 1 (Purolite CT 275, partially neutralized, 0.9 eq / L). Figure 1 Accordingly, a process is shown in which diisobutene is initially separated by distillation into 2,4,4-trimethylpent-1-ene and 2,4,4-trimethylpent-2-ene, in order to convert the TMP2-enriched stream at the bottom of the column back into a TMP1-enriched stream via a heterogeneous catalyst and then to supply it back to the distillative separation to provide a TMP1-enriched product stream.

[0064] The input stream "feed" consists of a mixture of TMP1 and TMP2 in a ratio of 81 wt.-% TMP1 and 19 wt.-% TMP2. It is supplied to a distillation column (1) operated with 100 theoretical plates at a reflux ratio of 8 via plate 50. The distillation column (1) is operated at 0.3 bar and a bottom temperature of 67° C. and a top temperature of 65.3° C. Stream S2 is obtained at the bottom of the column at 67° C., having a composition of 9.13 wt.-% TMP1 and 90.87 wt.-% TMP2, is cooled to 55° C. via a heat exchanger (2) and supplied as stream B to an isomerization reactor (3). The isomerization reactor (3) is filled with a heterogeneous catalyst (as mentioned in Example 1). An empty tube residence time of >24 minutes gives a stream S4 composed of 78 wt.-% TMP1 and 22 wt.-% TMP2. If a purge is necessary, this stream can be divided via a splitter (4) (factor 0.03) into a purge stream and a stream A. Stream A is supplied again to the distillation column (1) above plate 40. At the top of the distillation column (1), a completely condensed top stream K is obtained at a temperature of 63.5° C., wherein this stream has a composition of 96% by weight of TMP1 and 4% by weight of TMP2. An overview of the composition of the streams can also be seen in Table 2.

[0065] Table 2: Overview of the individual streams used for the simulation in Example 2

[0066]

[0067] It is evident that by means of the process according to the invention it is possible to obtain a top stream K having a very high content of 2,4,4-trimethylpent-1-ene.

Claims

1. A process for providing a top stream K containing more than 85% by weight of 2,4,4-trimethylpent-1-ene, wherein the process comprises at least the following steps: a. supplying a stream A comprising 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene to a distillation unit and separating said stream A into at least a top stream K which is enriched in 2,4,4-trimethylpent-1-ene relative to stream A and contains more than 85% by weight of 2,4,4-trimethylpent-1-ene and a stream B which is depleted in 2,4,4-trimethylpent-1-ene relative to stream A; b. isomerizing stream B to 2,4,4-trimethylpent-2-ene using a heterogeneous catalyst based on zeolites or ion exchange resins to obtain an isomerized product stream in which the proportion of 2,4,4-trimethylpent-2-ene is lower and the proportion of 2,4,4-trimethylpent-1-ene is higher than in stream B; in The product stream of the isomerization is sent at least partly as stream A to distillation, and wherein The input stream for feeding the process and containing 2,4,4-trimethylpent-2-ene and 2,4,4-trimethylpent-1-ene is sent, besides stream A, to the distillation unit in step a. and / or, besides stream B, to the isomerization in step b.

2. The process according to claim 1, wherein the distillation unit comprises at least one distillation column, preferably at least two distillation columns.

3. The process according to claim 1 or 2, wherein the at least one distillation column is operated under reduced pressure, preferably at a pressure of 0.2 to 0.9 bar.

4. The process according to any one of the preceding claims, wherein the bottom temperature of the at least one distillation column is from 50°C to 100°C.

5. The process according to any one of the preceding claims, wherein the reflux ratio of the at least one distillation column is from 5 to 15.

6. The process according to any of the preceding claims, wherein stream B of the at least one distillation column contains 80 to 92% by weight of 2,4,4-trimethylpent-2-ene.

7. The process according to claim 1, wherein stream B is taken off from the at least one distillation column as a bottom stream or as a side stream.

8. The process according to claim 5, wherein stream B is withdrawn as bottom stream of the at least one distillation column and a purge stream containing high boilers formed during the isomerization is withdrawn before or after the isomerization.

9. The process according to claim 5, wherein stream B is withdrawn as a side stream from the at least one distillation column and a stream containing high boilers formed during the isomerization is produced at the bottom of the at least one distillation column.

10. The process according to any of the preceding claims, wherein the isomerization in step b is carried out at a temperature of 25 to 90°C, preferably 30 to 80°C, particularly preferably 35 to 70°C.

11. A process according to any preceding claim, wherein the zeolite has a Si:Al ratio of from 40:1 to 200:

1.

12. The process according to any one of the preceding claims, wherein the zeolite is selected from beta- and gamma-zeolites.

13. A process according to any one of the preceding claims, wherein the catalyst is a zeolite and is selected from the group consisting of Z-β-H-25, Z-β-H-38, Z-β-H-360, Z-Mor-H-20, ZYH-60, ZYH-80, Z-β-H, Z-CFG-1, Z-β-ammonium-38, Z-CBV760CY(1.6), Z-CBV 780CY(1.6), CP 814E CY(1.6), CBV 500CY(1.6), H-CZB-150 and mixtures thereof.

14. The process according to claim 1, wherein the ion exchange resin used is an ion exchange resin which has been prepared by sulfonation of phenol / aldehyde condensates or by sulfonation of copolymers of aromatic vinyl compounds.

15. The process according to claim 1, wherein heat integration is carried out in step a. so that at least part of the condensation energy at the top of the column is used to heat the bottom product, preferably in the form of vapor compression or by using a heat pump.

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