Process for processing a methanol / water mixture in the production of alkali metal methanolates in a reaction column

Description

[0001] The present invention relates to a process for the work-up of a methanol / water mixture, which is used in the production of alkali metal methanolates in a reaction column. The mixture is separated by distillation in a rectification column. The vapors obtained at the top of the rectification column are compressed in at least two stages, and the energy of each compressed vapor is advantageously transferred to the bottom and side streams of the rectification column. This enables the particularly energy-efficient use of the energy from the compressed vapors in the process according to the invention.

[0002] The process for purifying a methanol / water mixture is used in the production of alkali metal methanolates in a reaction column, in which methanol and alkali liquor are reacted countercurrently. Alkali metal methanate dissolved in methanol is withdrawn from the lower end, and a methanol / water mixture is withdrawn from the upper end, which is then purified using the process according to the invention. The energy of the compressed vapors can also be used to operate the reaction column or to operate a reaction column in which a process for the alcoholization of alkali metal methanolates is carried out. 1. Background of the Experience

[0003] Alcohol / water mixtures are produced, for example, during the manufacture of alkali metal alcoholates from aqueous alkaline solutions, which may contain added alcohol, and alcohol. In these processes, methanol and ethanol are particularly commonly used as the alcohol.

[0004] Alkali metal alkoxides are used as strong bases in the synthesis of numerous chemicals, e.g., in the production of pharmaceuticals or agricultural active ingredients. Furthermore, alkali metal alkoxides are used as catalysts in transesterification and amidation reactions.

[0005] Alkali metal alcoholates (MOR) are produced from alkali metal hydroxides (MOH) and alcohols (ROH) by reactive distillation in a countercurrent distillation column, according to the following reaction. <1> The resulting reaction water is removed with the distillate. MOH + ROH MOR + H2O.

[0006] Such a process principle is described, for example, in US 2,877,274 A, in which aqueous alkali metal hydroxide solution and gaseous methanol are operated countercurrently in a reactive rectification column. This process, essentially unchanged, is described again in WO 01 / 42178 A1.

[0007] Similar processes, which additionally employ an entraining agent such as benzene, are described in GB 377,631 A and US 1,910,331 A. The entraining agent serves to separate the water and the water-soluble alcohol. In both patents, the condensate undergoes phase separation to remove the water of reaction. Another similar process is the reaction of an alkali metal alcoholate with another alcohol in a reaction column ("re-alcoholization") according to DE 27 26 491 A1.

[0008] Accordingly, DE 96 89 03 C describes a process for the continuous production of alkali metal alkoxides in a reaction column, wherein the water-alcohol mixture drawn off at the top is condensed and subsequently subjected to phase separation. The aqueous phase is discarded, and the alcoholic phase, along with the fresh alcohol, is returned to the column at the top. A similar process is described in EP 0 299 577 A2, in which the water separation in the condensate is carried out using a membrane. The most industrially important alkali metal alkoxides are those of sodium and potassium, and in particular the methylates and ethylates. Their synthesis is described in many instances in the prior art, for example in EP 1 997 794 A1.

[0009] In the prior art syntheses of alkali metal alkoxides by reactive rectification, vapors are typically obtained that comprise the alcohol and water used. For economic reasons, it is advantageous to reuse the alcohol contained in the vapors as a reactant in reactive distillation. Therefore, the vapors are usually fed into a rectification column, and the alcohol contained therein is separated (described, for example, in GB 737 453 A and US 4,566,947 A). The alcohol thus recovered is then, for example, fed as a reactant in reactive distillation.

[0010] Alternatively or additionally, a portion of the alcohol vapor can be used to heat the rectification column (described in WO 2010 / 097318 A1). However, the vapor must be compressed to reach the temperature required for heating the rectification column. Multi-stage compression of the vapor is particularly thermodynamically advantageous. In this process, the vapor is cooled between compression stages. Furthermore, this intercooling helps to ensure that the maximum permissible temperature of the compressor is not exceeded. The disadvantage of this cooling method, as used in conventional processes, is that the energy extracted is dissipated unused.

[0011] There is therefore a need for improved processes for the work-up of an alcohol / water mixture, which can be used particularly in the context of a process for the production of alkali metal alkoxides. This process should be characterized by a particularly efficient use of the energy contained in the compressed vapors for operating the rectification column. The process should thus enable energy-efficient use of the heat generated during the compression and cooling of the vapors. 2. Brief Summary of Experience

[0012] The present invention relates to a process for the production of at least one alkali metal alkoxide of the formula MA OR, wherein R is methyl, and wherein MA is a metal selected from sodium, potassium, preferably sodium.

[0013] In the process according to the invention for the production of at least one alkali metal alcoholate, a mixture Gcomprehensive water and methanol ROH obtained, which in a process for the work-up of a mixture G comprehensive water and raw alcohol, whereby R Methyl is used and is part of the process for processing a mixture. G is being processed. The process for processing a mixture G The process is carried out in a rectification column and is therefore a distillation process.

[0014] In a further, preferred aspect, the present invention relates to a process for the alcoholization of alkali metal alkoxides. In this process, the alcohol of an alkali metal alkoxide M c OR' is replaced by another alcohol R"OH, in which M c OR' is reacted with R"OH in a reaction column to form M c OR", wherein energy from certain vapor streams from the process according to the invention for the work-up of a mixture is extracted in the process. G is used for operation. 3. Abbildungen 3.1 Abbildung 1

[0015] Abbildung 1 shows a non-inventive embodiment of a process for the production of alkali metal methanolates, in which the distillative separation of the methanol-water mixture is carried out as in the prior art (WO 2010 / 097318 A1, Abbildung 1 ).

[0016] In this process, aqueous NaOH is used. With AE2 <102> in a reaction column RR A <100> with methanol With AE1 <103> It is converted to the corresponding sodium alkoxide at the top of the reaction column. RR A <100> An aqueous NaOH solution is used as the reactant current. With AE2 <102> Admittedly. Alternatively, a methanolic NaOH solution can also be used as the reactant current. With AE2 <102> to be added. To produce the corresponding potassium methoxide, aqueous or methanolic KOH solution is used as the reactant stream. With AE2 <102> Admittedly, above the sump of the reaction column. RR A <100> Methanol is used as a reactant stream With AE1<103> added in vapor form.

[0017] At the swamp of the reaction column RR A <100> A mixture of the corresponding methoxide is added to the methanol S AP* <104> extracted. With the sump evaporator V SA <105> and the optional evaporator V SA' <106> at the swamp of the column RR A <100> The concentration of the sodium methoxide solution will be S AP* <104> set to the desired value.

[0018] At the head of the reaction column RR A <100> A stream of vapors will form S AB <107> taken from the capacitor K RRA <108> becomes part of the Brünenstrom S AB <107> condensed and liquid as reflux to the top of the reaction column RR A <100> abandoned. Capacitor K RRA <108> However, adjusting the return flow is optional.

[0019] The preserved brothers S AB <107> is wholly or partially a rectification column, a water / methanol column, RD A <300> as a mixture G fed into the system. The rectification column RD A <300> includes built-in components <310> The mixture is contained within it. G separated by distillation, and at their head the methanol as vapors S OA <302> Recovered by distillation.

[0020] At the rectification column RD A <300> A return flow can be set. In this case, part of the vapor is... S OA <302> in a capacitor K RD <407> condensed and then returned to the rectification column RD A <300> returned. The remaining part of S OA <302> , or the entire vapor stream S OA <302> In embodiments where no return flow is set, a compressor is used. VD AB2 <303> Pre-compressed. A portion of this pre-compressed vapor is sent to the reaction column. RR A <100> recycled where it is used as feedstock With AE1 <103> is used. The remaining part of S OA<302> the compressor VD 1 <401> directed to where it continues to the Brüden Stream S OA1 <403> is compressed, from which the optional intercooler WT X <402> Energy can be dissipated.

[0021] The Brünen Stream S OA1 <403> is again using a compressor VD x <405> condensed and the resulting vapors S OA2 <404> the evaporator V SRD <406> at the swamp of the rectification column RD A <300> supplied for heating, after which fresh methanol may be added to it <408> is admitted and he returns to the rectification column RD A <300> is fed back in as reflux. If there is reflux at the rectification column RD A <300> When adjusted, the current can be S OA2 <404> , before he went into RD A <300> is returned, with the return flow, i.e. the condensate from K RD <407> , be mixed and together with this in RD A<300> to be fed. At the swamp of the rectification column RD A <300> a water stream US <304> received, which at least partially (electricity) S UA1 <320> ) back into the rectification column RD A <300> can be recycled, via the evaporator V SRD <406> and / or V SRD' <410> can be conducted. 3.2 Abbildung 2

[0022] Abbildung 2 shows a further non-inventive embodiment of a method, which is the one described in Abbildung 2 The embodiment shown in WO 2010 / 097318 A1 corresponds to this embodiment.

[0023] This embodiment corresponds to the one in Abbildung 1 described with the following additional or different features: In addition to the evaporators V SRD' <406> and V SRD' <410> The rectification column points towards the swamp. RD A <300> an intermediate evaporator V ZRD <409> up. A side stream S ZA <305> the rectification column RD A <300> extracted and about V ZRD <409> led, then the rectification column RD A <300> reintroduced. Part of the vapor stream. S OA <302> is achieved by means of a compressor VD AB2 <303> pre-compressed and, after a portion of it goes to the reaction column RR A <100> was diverted, in the compressor VD 1 <401> to the Bründen Stream S OA1 <403> compressed, and this to the intermediate evaporator V ZRD <409> supplied for heating. Heating in the evaporator. V SRD <406> or in the evaporator V SRD' <410> through S OA1 <403> This does not happen. The heating system for V ZRD <409> used vapor stream S OA <302> is then treated with the condensate from K RD <407> and the fresh methanol <408> mixed and returned to the rectification column RD A <300> returned. A separate return of the return flow from S OA <302> into the rectification column RD A <300> is also possible. 3.3 Abbildung 3

[0024] Abbildung 3 Figure 1 shows an embodiment of the process according to the invention. This corresponds to the embodiments described in Figures 1 and 2. The rectification column RD A <300> features an intermediate evaporator V ZRD <409> and a sump evaporator V SRD <406> and optionally the sump evaporator V SRD' <410> on.

[0025] The embodiment according to the invention has the following differences compared to the embodiments described above: 1. After compression of part of the vapor stream S OA <302> in the compressor VD 1 <401> will the Brünn stream S OA1 <403> in two parts S OA11 <4031> and S OA12 <4032> divided. 2. S OA11 <4031> is the intermediate evaporator V ZRD <409> to heat the electricity S ZA <305> supplied. 3. S OA12 <4032> will continue in the compressor VD x <405> to the electricity S OA2<404> condensed and S OA2 <404> the sump evaporator V SRD <406> to heat the electricity S UA1 <320> supplied. 4. After S OA11 <4031> and S OA2 <404> the respective evaporator V ZRD <409> or V SRD <406> Once they have left, they are combined and the combined stream is mixed with the return flow (i.e., the condensate from K RD <407> ) and the fresh methanol <408> mixed and into the rectification column RD A <300> returned. Separate return of these streams to the rectification column. RD A <300> is also possible.

[0026] Because of these differences, the energy of the breaths can S OA1 <403> compared to the embodiment according to Figures 1 and 2 for heating the rectification column RD A <300> can be used more efficiently. 3.4 Abbildung 4

[0027] Abbildung 4shows an embodiment of the method according to the invention. This corresponds to the one in Abbildung 3 described embodiments with the difference that in a second reaction column RR B <200> an aqueous KOH solution S BE2 <202> , with methanol, which is also used for conversion in RR A <100> used will,S BE1 <203> is converted to the corresponding potassium methoxide.

[0028] At the head of the reaction column RR B <200> An aqueous KOH solution is used as the reactant current. S BE2 <202> Admittedly. Alternatively, a methanolic KOH solution can also be used as the reactant current. S BE2 <202> to be added. Above the sump of the reaction column. RR B <200> Methanol is used as a reactant stream S BE1 <203> added in vapor form.

[0029] At the swamp of the reaction column RR B <200> A mixture of the corresponding methoxide is converted into methanol S BP* <204> extracted. With the sump evaporator V SB<205> and the optional evaporator V SB' <206> at the swamp of the column RR B <200> The concentration of the potassium methoxide solution will be S BP* <204> set to the desired value.

[0030] At the head of the reaction column RR B <200> A stream of vapors will form S BB <207> taken from the capacitor K RRB <208> becomes part of the Brünenstrom S BB <207> condensed and liquid as reflux to the top of the reaction column RR B <200> abandoned. Capacitor K RRB <208> However, adjusting the return flow is optional.

[0031] The preserved brothers S BB <207> is mixed with what is not in the capacitor K RRA <108> condensed part of the brute S AB <107> the rectification column RD A <300> supplied.

[0032] Another difference from the embodiment according to Abbildung 3 is that the pre-compressed part of the brute S OA<302> partially to the reaction column RR A <100> and RR B <200> is recycled where it is used as feedstock. With AE1 <103> or S BE1 <203> is used. 3.5 Abbildung 5

[0033] Abbildung 5 shows an embodiment of the method according to the invention. This corresponds to the one in Abbildung 4 described embodiments with the difference that a part of S OA2 <404> also for heating the evaporator V SA' <106> at the swamp of the column RR A <100> and the evaporator V SB' <206> at the swamp of the column RR B <200> is used. 3.6 Abbildung 6

[0034] Abbildung 6 shows an embodiment of the method according to the invention. This corresponds to the one in Abbildung 5 described embodiment with the difference that the reaction columns RR A <100> and RR B <200> each an intermediate evaporator V ZA <110> or V ZB<210> exhibit a side stream S ZAA <111> the reaction column RR A <100> extracted and about V ZA <110> guided, then the reaction column RR A <100> reintroduced. A side stream S ZBA <211> the reaction column RR B <200> extracted and about V ZB <210> guided, then the reaction column RR B <200> reintroduced.

[0035] Unlike Figure 5 will be part of S OA2 <404> only for heating the evaporator V SA' <106> at the swamp of the column RR A <100> used. In contrast, part of S OA11 <4031> for heating the evaporator V ZB <210> used. 3.7 Figure 7

[0036] Figure 7 shows an embodiment of the method according to the invention. This corresponds to the one in Figure 5 described embodiments with the difference that the reaction column RR A<100> an intermediate evaporator V ZA <110> exhibits a side stream S ZAA <111> the reaction column RR A <100> extracted and about V ZA <110> guided, then the reaction column RR A <100> reintroduced. Unlike Figure 5 will be part of S OA2 <404> only for heating the evaporator V SB' <206> at the swamp of the column RR B <200> used. The intermediate evaporator V ZA <110> is via a pump <501> transported heat transfer medium W <502> , especially water, heated, which transfers heat to the intercooler WT X <402> from S OA12 <4032> absorbs and in the intermediate evaporator V ZA <110> hands over. 3.8 Figure 8

[0037] Figure 8 shows an embodiment of the method according to the invention. This corresponds to the one in Figure 5 described embodiment with the difference that the reaction columns RR A<100> and RR B <200> each an intermediate evaporator V ZA <110> or V ZB <210> exhibit a side stream S ZAA <111> the reaction column RR A <100> extracted and about V ZA <110> guided, then the reaction column RR A <100> reintroduced. A side stream S ZBA <211> the reaction column RR B <200> extracted and about V ZB <210> guided, then the reaction column RR B <200> reintroduced.

[0038] In addition, it shows Figure 8 Another preferred embodiment of the process according to the invention. It shows a reactive rectification column. RR c <600> for the conversion of sodium methoxide to sodium ethoxide, which is at least partially powered by electricity. S OA12 <4032> is operated. The column RR c <600> indicates the sump evaporator V sc <605> and V sc' <606> on.

[0039] This involves sodium methoxide solution S CE1 <602> in a reaction column RR C <600> in countercurrent with ethanol S CE2 <603> converted to sodium ethoxide and this was withdrawn as an ethanolic solution.

[0040] At the swamp of the reaction column RR C <600> a swamp product stream S CP <604> Sodium ethoxide was extracted in large quantities.

[0041] At the head of the reaction column RR C <600> A stream of vapors will form S CB <607> taken from the capacitor K RRC <608> At least part of the vapor stream will be affected. S CB <607> condenses, and at least a portion of it returns to the top of the reaction column as liquid. RR C <600> abandoned. The Brüden Stream S CB <607> The process either occurs in a gaseous state before it reaches the condenser. K RRC <608> subtracted (indicated by a dashed line) and / or as a current <609> liquid behind the capacitor K RRC <608> .

[0042] A side stream S ZC <610> the reaction column RR C <600> preferably extracted, whereby via an intermediate evaporator V ZC <611> energy is transferred and S ZC <610> then back in RR C <600> can be returned.

[0043] As sodium methoxide solution S CE1 <602> Preferably, at least a portion of the components in the reaction column will be used. RR A <100> and RR B <200> recovered swamp streams S AP* <104> or S BP* <204> used.

[0044] The sump evaporator V SC' <606> is via a pump <501> transported heat transfer medium W 1 <502> , especially water, heated, which transfers heat to the intercooler WT X <402> from S OA12 <4032> absorbs and in the sump evaporator V SC' <606> hands over.

[0045] Alternatively, energy can also be selected from another source. S OA2 <404> , S OA11 <4031> , S OA1 <403> before the split into S OA11 and S OA12, on the sump evaporator V SC' <606> or the other sump evaporator V SC <605> be transmitted. By at least one of the streams S OA1 <403> , S OA11 <4031> , S OA12 <4032> , S OA2 <404> Energy can also be applied to the ethanol stream S CE1 <603> , the sodium methoxide solution S CE1 <602> or the side current S ZC <610> be transferred. 3.9 Figure 9

[0046] Figure 9 shows an embodiment of the method according to the invention. This corresponds to the one in Figure 8 described embodiment with the difference that the heating of the sump evaporator V sc' <606> directly with a part of S OA2 <404> This has been done. 3.10 Figure 10

[0047] Figure 10 The figure illustrates the energy savings in the inventive method according to Example 3 compared to the non-inventive method according to Examples 1 and 2. The x-axis denotes the respective example, the y-axis the power to be supplied in kW (heating steam and compressor power).

[0048] The hatched part of the bars represents the required heating power through low-pressure steam, the white part of the bars the sum of the compressor outputs. 4. Detailed description of the invention

[0049] The present invention relates to a process for the production of at least one alkali metal alkoxide of the formula MA OR, wherein R is methyl, and wherein MA is a metal selected from sodium, potassium, preferably sodium.

[0050] The method according to the invention comprises steps (a) to (f) a method for working up a mixture Gcomprising water and alcohol ROH, where R is methyl.

[0051] RAW is therefore methanol. 4.1 Process for the reprocessing of a mixture G

[0052] The inventive method for processing a mixture G comprises steps (a) to (f) of the process according to the invention for the preparation of at least one alkali metal alcoholate of the formula MA OR.

[0053] The mixture G If it is particularly gaseous, then it is also referred to as "brew".

[0054] In the mixture G This is the overhead stream of a reaction column in which the alcohol ROH was reacted with an alkali metal hydroxide NaOH or KOH to form the corresponding alkali metal alkoxide NaOR or KOR.

[0055] According to the invention, the mixture used in step (a) is defined as G at least part of the condensation S AB , and, if step (α2) is performed, at least a part of the vapor stream S BB ,used.

[0056] The Brünen Stream S AB is obtained in step (α1) (described in section 4.2.1).

[0057] The Brünen Stream S BB is obtained in the optional step (α2) if this step is performed (described in section 4.2.2).

[0058] The Brünen Stream S BB is only obtained if the optional step (α2) is performed. If the optional step (α2) is performed, S BB is obtained and at least part of S BB as a mixture G is used, at least one part of S BB mixed with S AB or separately from S AB as a mixture G used.

[0059] In step (β) of the process, at least a portion of the vapor stream is S AB , and, if step (α2) is performed, at least a part of the vapor stream S BB , mixed with S AB or separately from S AB ,as a mixture G in step (a) of a process for the reprocessing of a mixture G Extensive use of water and ROH alcohol.

[0060] The mixture G comprising water and alcohol ROH is produced according to the invention using the process for processing a mixture G processed. 4.1.1 Step (a) of the method according to the invention

[0061] In step (a) of the inventive method, the mixture G into a rectification column RD A guided and in RD A in at least one stream of vapors S OA comprehensive RAW, which is at the upper end of RD A is extracted, and at least one current S UA comprehensive water, which is located at the lower end of RD A It is extracted and separated.

[0062] "At least one stream of condensation S OA comprehensive RAW, which is at the upper end of RD A "is taken" means that the brothers, who are at the top of RD AIt is obtained from there as one or more vapor streams. If it is withdrawn from more than one vapor stream, the m vapor streams are referred to as a "vapor stream". S OAI ", "Brothers Stream S OAII ", [...], "Brothers Stream S OAm " denotes, where "m" is the number of elements at the upper end of RD A indicates extracted streams of water (in Roman numerals).

[0063] "At least one electricity S UA comprehensive water, which is located at the lower end of RD A "is extracted" means that water that is at the bottom of RD A The energy is obtained from there and can be drawn off as one or more streams. If it is drawn off there in more than one stream, the n streams are referred to as "streams". S UAI ", "Electricity S UAII ", [...], "Electricity S UAn " denotes, where "n" is the number of objects at the lower end of RD A indicates the currents extracted (in Roman numerals).

[0064] The mixture GThis can involve entering the rectification column via one or more inlets. RD A It is directed via several inlet points, for example, in embodiments in which step (α2) is carried out in the method according to the preferred aspect of the invention and at least a part of the vapor stream is directed in step (β). S BB separate from S AB , as a mixture G is used in step (a) of the process. In this embodiment, the mixture is therefore G as two separate streams into the rectification column RD A guided.

[0065] In the embodiments of the present invention, in which the mixture G as two or more separate streams into the rectification column R DA If the flow is directed, it is advantageous if the inlets of the individual streams are essentially at the same height on the rectification column. RD A lay.

[0066] In a preferred embodiment of step (a) of the method according to the invention, the mixture G in a rectification column RD A into a stream of vapors S OA comprehensive RAW, which is at the upper end of RD A is extracted, and a current S UA comprehensive water, which is located at the lower end of RD A It is extracted and separated.

[0067] Another term for "top end of a rectification column" is "head".

[0068] Another term for "lower end of a rectification column" is "swamp" or "foot".

[0069] The pressure exerted by at least one vapor stream S OA exhibits, is treated with " p OA," its temperature with " T OA is the designation. This refers in particular to the pressure and temperature of the at least one vapor stream. S OA, if it is in step (a) of the rectification column RD A is taken from it.

[0070] The pressure p OA is particularly in the range of 0.5 bar abs. to 8 bar abs., more preferably in the range of 0.6 bar abs. to 7 bar abs., more preferably in the range of 0.7 bar abs. to 6 bar abs., even more preferably in the range of 1 bar abs. to 5 bar abs., and is most preferably 1 bar abs. to 4 bar abs.

[0071] The temperature T OA is particularly in the range of 45 °C to 150 °C, more preferably in the range of 48 °C to 140 °C, more preferably in the range of 50 °C to 130 °C, even more preferably in the range of 60 °C to 120 °C, and is most preferably in the range of 60 °C to 110 °C.

[0072] As a rectification column RD A In step (a) of the process, any rectification column known to a person skilled in the art can be used. Preferably, the rectification column contains RD AInternal components. Suitable internal components include, for example, trays, unstructured packings, or structured packings. Common trays used are bubble-cap trays, sieve trays, valve trays, tunnel trays, or slotted trays. Unstructured packings are generally loose fills. Common fill materials include Raschig rings, Pall rings, Berl saddles, or Intalox® saddles. Structured packings are marketed, for example, under the trade name Mellapack® by Sulzer. In addition to the internal components mentioned, other suitable internal components are known to those skilled in the art and can also be used.

[0073] Preferred internals exhibit a low specific pressure drop per theoretical separation stage. Structured packings and fills, for example, have a significantly lower pressure drop per theoretical separation stage than trays. This has the advantage that the pressure drop in the rectification column is lower. RD Aso that the mechanical power of the compressor and the temperature of the alcohol / water mixture to be evaporated remain as low as possible.

[0074] If in the rectification column RD A Whether structured or unstructured packings are present, these may be divided or a single continuous packing may be used. However, at least two packings are usually provided, one packing above the point where the mixture enters the system. G and a package below the point where the mixture is supplied G. There can also be a package above the point where the mixture is supplied. G and several floors below the point where the mixture enters the ground G This is provided for. If an unstructured packing is used, for example a filler packing, the filler particles usually rest on a suitable support grid (e.g. sieve tray or grid tray).

[0075] In step (a) of the method according to the invention, the at least one vapor stream is then S OA Comprehensive ROH at the top of the rectification column RD A extracted. The preferred mass fraction of raw material in this vapor stream. S OA is ≥ 99 wt.%, preferably ≥ 99.6 wt.%, even more preferably ≥ 99.9 wt.%, the remainder being in particular water.

[0076] At the lower end of RD A will at least one current S UA water is extracted, which preferably contains < 1 wt.%, more preferably ≤ 5000 wt.ppm, and even more preferably ≤ 2000 wt.ppm alcohol.

[0077] The extraction of at least one vapor stream S OA Comprehensive ROH at the head of the rectification column RD A In the context of the present invention, this means in particular that the at least one vapor stream S OA as a headstream or as a side draw-off above the internals in the rectification column RD A is taken from it.

[0078] The withdrawal of at least one current S UA comprehensive water at the swamp of the rectification column RD In the context of the present invention, A means in particular that the at least one current S UA as a swamp stream or at the bottom of the rectification column RD A is taken from.

[0079] The rectification column RD A is operated with or without, preferably with, return flow.

[0080] "With reflux" means that the rectification column at the top is returned to its original state. RD A extracted vapor stream S OA is not completely removed, but partially condensed and returned to the respective rectification column. RD A is supplied. In cases where such a return flow is set, the return ratio is preferably 0.0001 to 1, more preferably 0.0005 to 0.9, and even more preferably 0.001 to 0.8.

[0081] A reflux can be set by adjusting the head of the rectification column. RD A a capacitor K RD is attached to the capacitor K RD The respective stream of vapors will be S OA partially condensed and the rectification column RD A The term reflux ratio generally refers, and is used in the context of this invention, to the ratio of the proportion of the mass flow (kg / h) withdrawn from the column that is returned to the column in liquid form (reflux) to the proportion of this mass flow (kg / h) that is discharged from the respective column in liquid or gaseous form. 4.1.2 Step (b) of the method according to the invention

[0082] In step (b) of the inventive method, at least one side stream is S ZA out of RD A removed and returned to RD A returned.

[0083] In a preferred embodiment of step (b) of the method according to the invention, a side stream is S ZA out of RD A removed and returned to RD A traced back.

[0084] "Side current S ZA out of RD A " According to the invention, this means that the current at a withdrawal point E ZA below the head and above the swamp of RD A is taken from and in particular additionally at an inlet point Z ZA (This is the point where the respective side stream S ZA re-enters the rectification column) RD A (is returned) below the head and above the swamp of RD A again in RD A is returned.

[0085] This means in particular that the sampling point E ZA , and also prefers the access point Z ZA of the respective lateral current S ZA at the rectification column RD A below the extraction points E OA all from RD A extracted vapor streams S OA is located, preferably at least 1, more preferably at least 5, more preferably at least 10 theoretical steps below the extraction point E OA that from RD A extracted vapor stream S OA , whose sampling point E OA furthest down the rectification column RD A lies, lies.

[0086] This also means, in particular, that the sampling point E ZA , and also prefers the access point Z ZA of the respective lateral current S ZA at the rectification column RD A above the extraction points E UA all from RD A extracted currents With UA preferably at least 1, more preferably at least 2, more preferably at least 4 theoretical steps above the extraction point E U A of the current With UA, whose sampling point E U A furthest up on the rectification column RD Alies, lies.

[0087] In cases where at least one vapor stream With OA at least partially returned to the rectification column RD A is recycled (which is the case, for example, when a return flow is present at the rectification column). RD A (is being discontinued), in particular the access point is also located there With OA (that is the point where at least one stream of vapors With OA at least partially returned to the rectification column RD A (is returned) of at least one vapor stream With OA above the extraction points E FOR and especially above the access points WITH FOR all from RD A extracted side streams WITH FOR , preferably at least 1, more preferably at least 5, even more preferably at least 10 theoretical steps above the highest point of all extraction and inlet points of all from RD A extracted side streams WITH FOR .

[0088] In cases where at least one current With UA at least partially returned to the rectification column RD A The return location is also, in particular, the access point With UA (that is the point where at least one current With UA at least partially returned to the rectification column RD A (is returned) of at least one current With UA below the extraction points E FOR and especially below the inlet points WITH FOR all from RD A extracted side streams WITH FOR , preferably at least 1, more preferably at least 2, even more preferably at least 4 theoretical levels below the lowest point of all extraction and inlet points of all from RD A extracted side streams WITH FOR .

[0089] The sampling point E FOR of the side current WITH FOR and the access point WITH FOR of the side current WITH FORat the rectification column RD A can choose between the same floors of RD A They may be positioned. However, it is also possible that they are at different heights.

[0090] In a preferred embodiment of the method according to the invention, the sampling point is located E FOR and also prefers the access point WITH FOR of at least one lateral stream WITH FOR at the rectification column RD A below the inlet ZG, at the mixture G into the rectification column RD A is directed, and above the swamp of RD A. The extraction points are even more preferred. E FOR and also prefers the access point WITH FOR of at least one lateral stream WITH FOR at the rectification column RD A also below the amplifier section of RD A.

[0091] In a particularly preferred embodiment of the method according to the invention, the sampling point is located E FOR and preferably also the access point WITH FOR of at least one lateral stream WITH FOR at the rectification column RD A in the upper 4 / 5, preferably upper 3 / 4, preferably upper 7 / 10, preferably upper 2 / 3, preferably upper 1 / 2 of the area at the rectification column RD A , the one below the inlet ZG, at the mixture G into the rectification column RD A is directed, lies, and above the uppermost of all extraction and inlet points of all from RD A extracted currents With UA lies.

[0092] The extraction points are even more preferred. E FOR and also prefers the access point WITH FOR of at least one lateral stream WITH FOR at the rectification column RD A then also below the amplifier section of RD A.

[0093] In a further particularly preferred embodiment of the method according to the invention, the rectification column contains RD A an amplifier section, and the extraction point is located there. E FOR and preferably also the access point WITH FOR of at least one lateral stream WITH FOR at the rectification column RD A in the upper 4 / 5, preferably upper 3 / 4, preferably upper 7 / 10, preferably upper 2 / 3, preferably upper 1 / 2 of the area at the rectification column RD A , the area below the amplifier section and above the uppermost of all extraction and inlet points of all from RD A extracted currents With UA lies. 4.1.3 Schritt (c) des engenzungen Verfahrens

[0094] In step (c) of the inventive method, at least a part of the at least one vapor stream is With OA ("at least part of at least one stream of condensation") With OA " = "at least part of With OA ") condenses. This creates a contrast with With OA compressed vapor stream With OA1 receive.

[0095] The pressure exerted by the vapor stream S OA1 is indicated with " p OA1, its temperature with " T OA1 " is designated.

[0096] The pressure p OA1 is higher than p OA. The exact value of p OA1 can be set by a person skilled in the art depending on the requirements in step (d), as long as the condition p OA1 > p OA is fulfilled. The quotient of p OA1 / p OA (pressures in bar abs.) is preferably in the range of 1.1 to 10, more preferably 1.2 to 8, more preferably 1.25 to 7, most preferably 1.3 to 6.

[0097] The temperature T OA1 is particularly higher than the temperature T OA, and the quotient of T OA1 / TOA (temperature in °C) is preferably in the range of 1.03 to 10, more preferably 1.04 to 9, more preferably 1.05 to 8, more preferably 1.06 to 7, more preferably 1.07 to 6, most preferably 1.08 to 5.

[0098] The preferred values ​​of p OA1 and T OA1 also apply preferentially to With OA11 and With OA12.

[0099] The compression of at least part of the vapor stream With OAStep (c) can be carried out in any manner known to those skilled in the art. For example, the compression can be performed mechanically and in a single stage or in multiple stages, preferably in multiple stages. In multi-stage compression, several compressors of the same design or compressors of different designs can be used. Multi-stage compression can be carried out with one or more compressor machines. The use of single-stage or multi-stage compression depends on the compression ratio and thus on the pressure to which the vapors are compressed. With OA It is to be compacted.

[0100] As a compressor in the inventive method, in particular for compressing the vapor streams With OA to With OA1 or With OA12 to With OA2,Any compressor known to experts, preferably mechanical compressors capable of compressing gas flows, is suitable. Examples of suitable compressors include single- or multi-stage turbines, piston compressors, screw compressors, centrifugal compressors, and axial compressors.

[0101] In multi-stage compression, suitable compressors are used for each pressure stage to be overcome. 4.1.4 Schritt (d) des engenzungen Verfahrens

[0102] In step (d) of the method according to the invention, energy is supplied by a first part With OA11 of the condensed vapor stream With OA1 on WITH FOR transferred before WITH FOR in RD A is returned.

[0103] S OA1 is first divided into at least two parts, particularly in step (d). S OA11 and S OA12 is divided. The ratio of the mass flows (in kg / h) of S OA11 to SOA12 is preferably in the range of 1:99 to 99:1, more preferably in the range of 1:50 to 50:1, even more preferably in the range of 1:20 to 30:1, and still more preferably in the range of 5:20 to 15:1.

[0104] In step (d) of the inventive method, energy is transferred from the first part S OA11 on S ZA transferred. Through step (d), the energy decreases from S OA11, so that in particular the current S OA11 at least partially condensed.

[0105] According to the invention, "transfer of energy" means in particular "heating", i.e. transfer of energy in the form of heat.

[0106] "Transfer of energy from a first part S OA11 of the condensed vapor stream S OA1 on WITH FOR " This also includes cases where part of With OA11 is separated and only this part provides energy WITH FORis transferred. This is the case, for example, in those embodiments of the invention in which additional energy is transferred from With OA11 on the raw product RP A and, if step (α2) is performed, alternatively or additionally on the raw product RP B is transferred (described in section 4.2).

[0107] The transfer of energy from With OA11 on WITH FOR , preferably the heating of WITH FOR through With OA11 This is preferably done directly or indirectly.

[0108] "Direct" means that With OA11 with WITH FOR contact is made without the two streams mixing, so that energy, especially heat, is transferred from With OA11 on WITH FOR transitions.

[0109] This can be done by With OA11 and WITH FOR through an intermediate evaporator In the Federal Republic of Germany at the rectification column RD A be guided and With OA11 the WITH FOR heated.

[0110] As heat exchangers (another term for "heat transfer medium" = "heat exchanger"), in particular as the heat exchangers mentioned below WT X , WT Y , WT Z, heat exchangers familiar to those skilled in the art, in particular evaporators, can be used. In step (d) of the method according to the invention, the transfer of energy, preferably heat, takes place in particular from S OA11 on S ZA in an intermediate evaporator V ZRD .

[0111] "Indirect" means in particular that S OA11 with a heat transfer fluid W 1, preferably via at least one heat exchanger WT X , is contacted, whereby the heat transfer medium is not WITH FOR it W 1 also of WITH FOR is different, so that energy, preferably heat, is drawn from S OA11 on W 1 transitions without the two streams mixing, and the heat is then transferred from W1 on WITH FOR transitions in which W 1 S FOR contacted, whereby WITH FOR and W 1 Mix or don't mix, but preferably don't mix. If... W 1 and WITH FOR Without mixing, the energy, preferably heat, is transferred, particularly in a further heat exchanger. WT Y .

[0112] In a further embodiment of the method according to the invention, indirect energy transfer from With OA11 on WITH FOR , especially heating of WITH FOR through With OA11, also initially energy, preferably heat from With OA11 on W 1 , preferably by contact via at least one heat exchanger WT X be transferred, and then from W 1 on another one, from WITH FOR various heat transfer fluids W 2 , preferably by contact via at least one heat exchanger WT Y , are transferred. In the final step, the heat is then transferred fromW 2 on WITH FOR , where WITH FOR and W 2 Mix or don't mix, but preferably don't mix. If... W 2 and WITH FOR Without mixing, the energy, preferably heat, is transferred, particularly in a further heat exchanger. WT Z .

[0113] It goes without saying that further embodiments of the present invention may include additional heat transfer media. W3, W4, W5 etc.

[0114] As a heat transfer medium W 1 or, in addition, heat transfer fluids that are still used W2, W3, W4, W5Any heat transfer fluid known to a person skilled in the art can be used; preferably, they are selected from the group consisting of water; alcohol-water solutions; salt-water solutions, which also include ionic liquids such as LiBr solutions, dialkylimidazolium salts such as, in particular, dialkylimidazolium dialkyl phosphates; mineral oils such as diesel oils; thermal oils such as silicone oils; biological oils such as limonene; aromatic hydrocarbons such as dibenzyltoluene. The most preferred heat transfer fluid is... W 1 Water.

[0115] Saltwater solutions that can be used are also described, for example, in DE 10 2005 028 451 A1 and WO 2006 / 134015 A1.

[0116] Following step (d) With OA11 then back to the rectification column RD A , possibly together with fresh alcohol and / or with the reflux of the rectification column RD A ,be fed in. In a preferred embodiment, from With OA11, especially after the transfer of energy to WITH FOR , transfer further energy.

[0117] In a preferred embodiment of the method according to the invention, energy, preferably heat, is extracted from With OA11, after With OA11 Energy on WITH FOR as per step (d) has transferred to With OA transferred, in particular to the part of With OA transferred, which is subjected to compaction, preferably the compaction in step (c), wherein a pre-compaction of With OA or the compaction of With OA to With OA1 can act. Preferably, this is the first compression, to which the current flows. With OA, after the column RD A has left, is subjected to. This makes it possible to recover part of what is still left of With OA11to use stored residual energy or residual heat in the process, in this case to heat the material to be compressed With OA.

[0118] This may lead to With OA Existing droplets evaporate, thus preventing droplets from entering the compressor.

[0119] Other, preferred additional sinks for energy, preferably heat in With OA11, are described further below (see paragraph 4.3).

[0120] Step (d) of the method according to the invention reflects an aspect of the unexpected effect of the present invention. In this step, the vapor stream is dissipated during compression. With OA to the condensed vapor stream With OA1 The excess energy obtained is not wasted, but is used in rectification. This is done by first condensing the S OA to S OA1 This is done, whereby a setting to the value that is necessary for energy transfer from With OA11 on WITH FORis optimal, is enabled, and then a of With OA11 various part With OA12 continue on With OA2 can be compressed. The heat of condensation, which occurs during further compression of With OA12 continue on With OA2 The recovered material is fed into the column in the sump evaporator. The required additional compressor power is less than the heating steam power saved as a result. The process according to the invention requires less energy than the prior art process, as shown in Examples 1 and 2. With compression to With OA2 pressure and temperature of With OA2 so that optimal energy transfer from With OA2 on With UA1 or With UA can be done. 4.1.5 Schritt (e) des engenzungen Verfahrens

[0121] In step (e) of the method of the invention, a With OA11 different part of the condensed vapor stream S OA1 , S OA12 , is further compacted, resulting in a difference S OA11 compressed vapor stream S OA2 will be received.

[0122] It goes without saying that S OA2 after completion of step (e) also vis-à-vis S OA12 and S OA1 is compacted.

[0123] The pressure exerted by the vapor stream S OA2 is indicated with " p OA2, its temperature with " T OA2 " is designated.

[0124] The pressure p OA2 is higher than p OA1, and the quotient of p OA2 / p OA1 (pressures in bar abs.) is preferably in the range of 1.1 to 10, more preferably 1.2 to 8, more preferably 1.25 to 7, most preferably 1.3 to 6.

[0125] The temperature T OA2 is particularly higher than the temperature T OA1 and the quotient of T OA2 / TOA1 (temperature in °C) is preferably in the range of 1.03 to 10, more preferably 1.04 to 9, more preferably 1.05 to 8, more preferably 1.06 to 7, more preferably 1.07 to 6, most preferably 1.08 to 5.

[0126] The compaction of S OA12 Step (e) can be carried out according to a method known to those skilled in the art. For example, the compression can be carried out mechanically in a single stage or in multiple stages, preferably in multiple stages. In multi-stage compression, several compressors of the same design or compressors of different designs can be used. The use of single-stage or multi-stage compression depends on the pressure to which the vapors are to be compressed. S OA12 to be condensed. One in the context of step (c) for S OA The described pre-compaction can also be used for the compaction of S OA12 to S OA2 carried out, in particular in step (e) compression in one stage is sufficient, i.e. using a compressor VD X . 4.1.6 Schritt (f) des erfindungsgemäßen Verfahrens

[0127] In step (f) of the method according to the invention, energy is extracted from at least a part of S OA2 at least one part S UA1 of at least one current S UA transferred before S UA1 in RD A is returned.

[0128] Preferably, in step (f) of the process, according to the energy of at least a part of S OA2 on a part S UA1 of at least one current S UA transferred before S UA1 in RD A is returned.

[0129] Step (f) reduces the energy of S OA2 , so that in particular the electricity S OA2 at least partially condensed

[0130] Step (f) of the method according to the invention comprises the following preferred embodiments (f1), (f2), (f3): (f1) Energy is supplied by at least part of S OA2 on a part S UA1 of at least one current S UA transferred, and S UA1 then in RD A (f2) Energy is recovered by at least part of S OA2 on a part S UA1* of at least one current S UA transferred, and from S UA1* will then be a part S UA1 in RD A (f3) Energy is recovered by at least part of S OA2 on the entire current S UA transferred and then the entire current S UA or only a part S UA1 of the current S UA , preferably only a part S UA1 of the current S UA , in RD A returned.

[0131] The transfer of energy from at least one part of S OA2 on at least one part S UA1 of at least one current S UA , preferably the heating of at least one part S UA1 of at least one current S UA through at least part of S OA2 , This is preferably done directly or indirectly.

[0132] "Direct" means that at least part of S OA2 with at least one part S UA1 of at least one stream S UA is contacted without the two streams mixing, so that energy, especially heat, is transferred from at least one part S OA2 on at least one part S UA1 of at least one stream S UA passes over.

[0133] This can be done by making at least one part of S OA2 and at least one part S UA1 of at least one stream S UA through a sump evaporator V SRD at the rectification column RD A be guided and S OA11 at least one part S UA1 of at least one current S UA heated.

[0134] As heat exchangers, in particular as the heat exchangers mentioned below WT X , WT Y , WT Z , heat exchangers familiar to those skilled in the art, in particular evaporators, can be used. In step (f) of the method according to the invention, the transfer of energy, preferably heat, from at least a part of S OA2 on at least one part S UA1 of at least one current S UA in a sump evaporator V SRD .

[0135] "Indirect" means, in particular, that at least one part of S OA2 with at least one heat transfer medium W 1 , preferably via at least one heat exchanger WT X , is contacted, whereby the heat transfer medium is not at least one part S UA1 of at least one current S UA it W 1 that is different from it, so that energy, preferably heat, is extracted from at least a part of it. S OA2 on the at least one heat transfer medium W 1 transitions without the two streams mixing, and the heat is then transferred from W 1 on at least one part S UA1 of at least one current S UA transitions in which W 1 the component in question is contacted, whereby at least one part S UA1 of at least one current S UA and W 1 Mix or don't mix, but preferably don't mix.

[0136] In a further embodiment of the method according to the invention, indirect energy transfer from at least a part of S OA2 on at least one part S UA1 of at least one current S UA , in particular heating of at least one part S UA1 of at least one current S UA through at least part of S OA2 , also initially energy, preferably heat from S OA2 on W 1 , preferably by contact via at least one heat exchanger WT X be transferred, and then from W 1 on another one, of which at least a part S UA1 of at least one current S UA various heat transfer fluids W 2 , preferably by contact via at least one heat exchanger WT Y , are transferred. In the final step, the heat is then transferred from W 2 on at least one part S UA1 of at least one current S UA , where at least one part S UA1 of at least one current S UA and W 2 Mix or not mix, but preferably not mix. It goes without saying that further embodiments of the present invention may include additional heat transfer media. W 3 , W 4 , W 5 etc.

[0137] As a heat transfer medium W 1 or, in addition, heat transfer fluids that are still used W 2 , W 3 , W 4 , W 5 Any heat transfer fluid known to a person skilled in the art can be used; preferably, they are selected from the group consisting of water; alcohol-water solutions; salt-water solutions, which also include ionic liquids such as LiBr solutions, dialkylimidazolium salts such as, in particular, dialkylimidazolium dialkyl phosphates; mineral oils such as diesel oils; thermal oils such as silicone oils; biological oils such as limonene; aromatic hydrocarbons such as dibenzyltoluene. The most preferred heat transfer fluid is... W 1 Water.

[0138] Saltwater solutions that can be used are also described, for example, in DE 10 2005 028 451 A1 and WO 2006 / 134015 A1.

[0139] Following step (f), at least one part of S OA2 then back to the rectification column RD A , possibly together with fresh alcohol and / or with the reflux of the rectification column RD A and / or with the current obtained after performing step (d) S OA11 be fed in. In a preferred embodiment, at least a portion of S OA2 , especially after the transfer of energy to at least one part S UA1 from S UA , transfer further energy.

[0140] In a preferred embodiment of the method according to the invention, energy, preferably heat, is extracted from at least a part of S OA2 , after this energy is applied to at least one part S UA1 from S UA according to step (f) was transferred to S OA transferred, in particular to the part of S OA transferred, which is subjected to compaction, preferably the compaction in step (c), wherein a pre-compaction of S OA or the compaction of S OA to S OA1 can act. Preferably, this is the first compression, to which the current flows. S OA , after the column RD A has left, is subjected. This makes it possible to recover a portion of what is still left of at least one part. S OA2 Using stored residual energy or residual heat in the process, in this case for heating material to be compressed S OA .

[0141] Other, preferred additional sinks for energy, preferably heat, in which at least a portion of S OA2 , are described further below (see paragraph 4.3). 4.2 Verfahren zur Herstellung mindestens eines Alkalimetallalkoholats

[0142] The process for reprocessing a mixture G mixture used according to the invention G is a water / methanol mixture taken from a reaction column for the production of alkali metal alcoholates.

[0143] The present invention thus relates to a process for the production of at least one alkali metal alkoxide of the formula MA OR, wherein R is methyl, and wherein MA is a metal selected from sodium, potassium, preferably sodium.

[0144] RAW is therefore methanol. 4.2.1 Schritt (α1)

[0145] In step (α1) of the method according to the invention, a reactant current is S AE1 comprehensive ROH with a reactant current S AE2 comprehensive MA OH in countercurrent flow in a reactivation column RR A to a raw product RP A comprehensively implemented MA OR, water, ROH, MA OH.

[0146] According to the invention, a "reactive rectification column" is defined as a rectification column in which, at least in some parts, the reaction according to step (α1) or step (α2) of the process according to the invention takes place. It can also be abbreviated as "reaction column".

[0147] In step (α1) at the lower end of RR A a swamp product stream S AP Extensively raw and raw materials were extracted. At the upper end of RR A A stream of vapors will form S AB Extensive water and ROH extraction.

[0148] MA is selected from sodium, potassium, and preferentially sodium.

[0149] The reactant current S AE1 includes raw material. In a preferred embodiment, the mass fraction of raw material is in S AE1 at ≥ 95 wt.%, even more preferably at ≥ 99 wt.%, wherein S AE1 otherwise contains, in particular, water.

[0150] The reactant current in step (α1) S AE1 The alcohol used in ROH can also be commercially available alcohol with an alcohol mass fraction of more than 99.8 wt.% and a water mass fraction of up to 0.2 wt.%.

[0151] The reactant current S AE1 is preferably added in vapor form.

[0152] The reactant current S AE2 MA OH includes. In a preferred embodiment, it includes S AE2 In addition to MA OH, at least one other compound selected from water, ROH. Even more preferably comprising S AE2 besides MA OH water, then it is a matter of S AE2 to obtain an aqueous solution of MA OH.

[0153] If the reactant current S AE2 If MA OH and water are included, the mass fraction of MA OH, based on the total weight of the aqueous solution, which S AE2 forms, in particular in the range of 10 to 75 wt.%, preferably from 15 to 54 wt.%, more preferably from 30 to 53 wt.% and most preferably from 40 to 52 wt.%.

[0154] If the reactant current S AE2 The mass fraction of MA OH in ROH, based on the total weight of the solution, is MA OH and ROH. S AE2 forms, in particular in the range of 10 to 75 wt.%, preferably from 15 to 54 wt.%, more preferably from 30 to 53 wt.%, and most preferably from 40 to 52 wt.%.

[0155] In the special case where the reactant current S AE2 In addition to MA OH, which includes both water and ROH, it is particularly preferred that the mass fraction of MA OH in ROH and water, based on the total weight of the solution, which S AE2 forms, in particular in the range of 10 to 575 wt.%, preferably from 15 to 54 wt.%, more preferably from 30 to 53 wt.%, and most preferably from 40 to 52 wt.%.

[0156] Step (α1) is performed in a reactive rectification column (or "reaction column") RR A carried out.

[0157] Step (α2), which is explained further below, is carried out in a reactive rectification column (or "reaction column") RR B carried out.

[0158] Preferably the reaction column contains RR A or RR B Internals. Suitable internals include, for example, trays, structured packings, or unstructured packings. When the reaction column RR A or RR B If the reaction column contains trays, then bubble-cap trays, valve trays, tunnel trays, Thormann trays, cross-slotted bubble-cap trays, or sieve trays are suitable. RR A or RR B If the system contains trays, trays are preferably selected in which a maximum of 5% by weight, and preferably less than 1% by weight, of the liquid passes through the respective trays. The design measures required to minimize liquid percolation are familiar to those skilled in the art. For example, particularly tightly sealing valve designs are selected for valve trays. Furthermore, by reducing the number of valves, the vapor velocity in the tray openings can be doubled to the value that is usually set. When using sieve trays, it is particularly advantageous to reduce the diameters of the tray openings and to maintain or even increase the number of openings.

[0159] When using structured or unstructured packings, structured packings are preferred with regard to the uniform distribution of the liquid.

[0160] In columns with unstructured packing, particularly with packing materials, and in columns with structured packing, the desired liquid distribution characteristics can be achieved by reducing the liquid spray density in the outer region of the column cross-section adjacent to the column shell, which corresponds to approximately 2 to 5% of the total column cross-section, by up to 100%, preferably by 5 to 15%, compared to the other cross-sectional areas. This can be achieved, for example, by the targeted distribution of the drip points of the liquid distributors or their bores using simple means.

[0161] The process according to the invention can be carried out both continuously and discontinuously. It is preferably carried out continuously.

[0162] "Conversion of a reactant current S AE1 comprehensive ROH with a reactant current S AE2 "comprising MA OH in countercurrent" is ensured according to the invention in particular by the fact that the inlet point of at least a part of the reactant current S AE1 comprehensively RAW in step (α1) at the reaction column RR A below the point where the reactant current enters the building S AE2 comprehensive MA OH lies. The reaction column RR A preferably comprises at least 2, in particular 15 to 40 theoretical stages between the point where the reactant current enters the circuit S AE1 and the point where the reactant current enters the building S AE2 .

[0163] The reaction column RR A It can be operated as a pure stripping column. Then, in the lower section of the reaction column... RR A The reactant current is vaporous. S AE1 Comprehensive raw material is supplied. Step (α1) also includes the case where part of the reactant current is supplied. S AE1 comprehensively, raw materials are located below the point where the reactant current enters the building. S AE2 comprehensive alkali hydroxide MA OH, but nevertheless at the top end or in the area of ​​the top end of the reaction column RR A is added in vapor form. This allows the dimensions in the lower section of reaction column RR A to be reduced. If part of the reactant stream S AE1 comprehensive ROH, namely

[0164] Methanol, at the top end or in the area of ​​the top end of the reaction column RR A If, in particular, the alcohol is added in vapor form, only a partial amount of 10 to 70 wt.%, preferably 30 to 50 wt.% (in each case based on the total amount of the alcohol ROH used in step (α1)) is present at the lower end of the reaction column. RR A fed in and the remaining subset distributed in a single stream or across several substreams, preferably 1 to 10 theoretical stages, particularly preferably 1 to 3 theoretical stages below the feed point of the reactant stream. S AE2 MA OH was added in vapor form.

[0165] In the reaction column RR A The reactant current then continues S AE1 comprehensively raw material with the emulsifier current S AE2 comprehensive MA OH according to the reaction described above <1> to MA OR and H₂O, whereby, since this is an equilibrium reaction, these products are present in a mixture with the reactants ROH and MA OH. Therefore, in step (α1) a crude product is formed. RP A in the reaction column RR A received, which includes not only the products MA OR and water, but also ROH and MA OH.

[0166] At the lower end of RR A One then obtains and extracts the swamp product stream S AP comprehensive ROH and MA OR.

[0167] At the top end of RR A , preferably at the column head of RR A , one extracts the alcohol stream still containing water, referred to above as "brew stream". S AB encompassing water and raw materials."

[0168] This stream of vapors S AB The water and raw material are at least partially mixed in step (β). G in step (a) of the process according to the invention. A portion of the distillation in step (a) is present in the stream. S OA The recovered alcohol can be used in the reaction column RR A as reactant current S AE1 be supplied.

[0169] In a preferred embodiment of the method according to the invention, a portion of S OA in step (α1) as reactant current S AE1 and, if step (α2) is performed, alternatively or additionally in step (α2) as reactant current S BE1 used.

[0170] In a more preferred embodiment of the method according to the invention, 5 to 95 wt.%, preferably 10 to 90 wt.%, more preferably 20 to 80 wt.%, and even more preferably 30 to 70 wt.% of the vapor stream are S OA as reactant current S AE1 or, if step (α2) is performed, alternatively or additionally in step (α2) as reactant current S BE1 used.

[0171] In this preferred embodiment, it is advantageous to direct the portion of the current S OA , which is considered reactant current S AE1 or as reactant current S BE1 is used to compact.

[0172] The amount of the reactant current S AE1 The included alcohol ROH is preferably selected such that it simultaneously serves as a solvent for the substance in the bottoms product stream. S AP The resulting alkali alkoxide MA OR serves as the basis. Preferably, the amount of alcohol ROH in the reactant stream is S AE1chosen so that the desired concentration of the alkali alkoxide solution is present in the bottom of the reaction column, which is then used as the bottom product stream. S AP Comprehensive raw materials and raw materials are extracted.

[0173] In a preferred embodiment of the method according to the invention, and particularly in cases where S AE2 In addition to MA OH, which also includes water, the ratio of the total weight (mass; unit: kg) in step (α1) as reactant current is S AE1 The amount of raw alcohol used is added to the total weight (mass; unit: kg) in step (α1) as a reactant current. S AE2 MA OH used in ratios of 4:1 to 50:1, preferably 8:1 to 48:1, even more preferred 10:1 to 45:1, and still more preferred 20:1 to 40:1.

[0174] The reaction column RR A It is operated with or without, preferably with, return flow.

[0175] "With reflux" means that the reaction column is located at the top of the respective column, in step (α1) of the reaction column. RR A , in step (α2) of the reaction column RR B , extracted vapor stream S AB or S BB The water and raw material are not completely removed. In step (β), the relevant vapor stream is then... S AB or S BB so not completely as a mixture G used, but at least partially, preferably partially, again as reflux of the respective column, in step (α1) of the reaction column RR A , in step (α2) of the reaction column RR B , supplied. In cases where such a return flow is set, the return ratio is preferably 0.01 to 1, more preferably 0.02 to 0.9, even more preferably 0.03 to 0.34, particularly preferably 0.04 to 0.27 and most particularly preferably 0.05 to 0.24.

[0176] A reflux can be set up by attaching a condenser to the top of the respective column. In step (α1), this is done in particular on the reaction column. RR A a capacitor K RRA This is done in step (α2), in particular at the reaction column. RR B a capacitor K RRB attached. S AB or S BB at least partially condensed and the respective column, in step (α1) of the reaction column RR A or RR B is reintroduced.

[0177] In the embodiment in which the reaction column RR A If a return flow is set, the current in step (α1) can be used as the reactant current. S AE2 The MA OH used should also be at least partially mixed with the return flow and the resulting mixture should be fed to step (α1).

[0178] Step (α1) is carried out particularly at a temperature in the range of 45 °C to 150 °C, preferably 47 °C to 120 °C, more preferably 60 °C to 110 °C, and at a pressure of 0.5 bar abs. to 40 bar abs., preferably in the range of 0.7 bar abs. to 5 bar abs., more preferably in the range of 0.8 bar abs. to 4 bar abs., more preferably in the range of 0.9 bar abs. to 3.5 bar abs., and even more preferably at 1.0 bar abs. to 3 bar abs.

[0179] The reaction column RR A In a preferred embodiment, it comprises at least one evaporator, which in particular consists of intermediate evaporators. V ZA and sump evaporators V SA is selected. The reaction column RR A preferably includes at least one sump evaporator V SA

[0180] As an "intermediate evaporator" VAccording to the invention, Z are evaporators located above the bottom of the respective column, in particular above the bottom of the reaction column. RR A or RR B (then as " V ZA " or " V e.g. " designated) or above the sump of the rectification column RD A (then as " V ZRD (referred to as "ZRD"). In the case of RR A or RR B In them, especially raw product RP A or RP B evaporates, which flows from the column as a side stream S ZAA or S ZBA is taken from it.

[0181] As a "swamp evaporator" VS According to the invention, evaporators are defined as those that remove the bottom of the respective column, in particular the bottom of the reaction column. RR A or RR B or the one used in the preferred embodiment and described in more detail below RR C (then as " V SA " or " V SA' " or " V SB " or "V SB' " or " V SC or " V SC' " designated) or the swamp of the rectification column RD A (then as " V SRD or V SRD' (designated) heat. In the case of RR A or RR B In particular, at least a portion of the swamp product stream is contained within them. S AP or AP. S BP evaporates. In the case of RR C In particular, swamp product stream is contained in them S CP evaporates. In the case of RD A In particular, swamp product stream is contained in them S UA or part of S UA , S UA1 , evaporated.

[0182] An evaporator is typically located outside the respective reaction column or rectification column. Since energy, especially heat, is transferred from one stream to another in evaporators, they are heat exchangers. WT.The mixture to be evaporated is drawn off from the column via a draw-off nozzle and fed to at least one evaporator. In the case of the reaction column... RR A or RR B is used during the intermediate evaporation of the raw product RP A or RP B, this subtracted and the at least one intermediate evaporator V ZA or V ZB supplied.

[0183] In the case of the rectification column RD At least one side stream will be present during intermediate evaporation. S ZA out RD A taken from ("subtracted") and the at least one intermediate evaporator V ZRD supplied.

[0184] In the case of the rectification column RD At least one stream will be generated during sump evaporation. S UA out RD A removed (“withdrawn”) and at least one part, preferably one part, to which at least one sump evaporator V SRD supplied.

[0185] The vaporized mixture, possibly with a residual liquid, is returned to the respective column via at least one inlet. This applies particularly if the evaporator is an intermediate evaporator. V ZA or V ZB or V ZRD In this context, the outlet through which the respective mixture is drawn off and fed to the evaporator is a side outlet, and the inlet through which the evaporated mixture is fed back to the respective column is a side inlet. If the evaporator is a bottom evaporator, i.e., it heats the column sump, then it is specifically a bottom evaporator. V SA or V SB or V SRD If this is the case, then at least part of the swamp drainage flow, in particular S AP or S BP ,The vapor is fed to the sump evaporator, evaporated, and returned to the respective column in the sump area. Alternatively, it is also possible, for example on a suitable tray when using an intermediate evaporator or in the sump of the respective column, to form tubes that are fed by the heat transfer medium, e.g., the respective compressed vapor stream. S OA1 or S OA2 (if VS or VZ at the rectification column RD A are located) or a heat medium W 1 The liquid is flowed through the column. In this case, evaporation takes place at the bottom or in the sump of the column. However, it is preferable to arrange the evaporator outside the respective column.

[0186] Suitable evaporators that can be used as intermediate and sump evaporators include, for example, natural circulation evaporators, forced circulation evaporators, forced circulation evaporators with expansion, boiler evaporators, falling film evaporators, and thin-film evaporators. A tube bundle or plate heat exchanger is typically used as the heat exchanger for the evaporator in both natural and forced circulation evaporators. When using a tube bundle heat exchanger, the heat transfer medium, e.g., the compressed vapor stream, can be transferred to the heat exchanger. S OA1 or S OA2 in V SRD or V ZRD at the rectification column RD A or the heat medium W 1 either flow through the pipes and the mixture to be evaporated flows around the pipes, or the heat transfer medium, e.g. the compressed vapor stream. S OA1 or S OA2 in V SRD or V ZRD at the rectification column RD A or the heat medium W 1 The liquid flows around the tubes, and the mixture to be evaporated flows through them. In a falling-film evaporator, the mixture to be evaporated is typically added as a thin film on the inside of a tube, and the tube is heated from the outside. Unlike a falling-film evaporator, a thin-film evaporator also incorporates a rotor with wipers that spreads the liquid to be evaporated onto the inner wall of the tube, forming a thin film.

[0187] In addition to those mentioned, any other type of evaporator known to experts that is suitable for use on a rectification column can also be used.

[0188] If the evaporator, which for example uses the compressed vapor stream S OA1 or the heat medium W 1 If the intermediate evaporator is operated as heating steam, it is preferred if the intermediate evaporator is located in the stripping section of the rectification column. RD Ain the area between the point where the mixture is fed in G and above the column sump or, in the case of reaction columns, RR A or RR B below the point where the reactant current enters the building S AE2 or S BE2 is arranged. This allows a majority of the heating energy to be introduced through the intermediate evaporator. For example, it is possible to introduce over 80% of the energy via the intermediate evaporator. According to the invention, the intermediate evaporator is preferably arranged and / or designed such that it introduces more than 10%, and in particular more than 20%, of the total energy required for distillation.

[0189] When using an intermediate evaporator, it is particularly advantageous if the intermediate evaporator is arranged such that the respective rectification column or reaction column has 1 to 50 theoretical stages below the intermediate evaporator and 1 to 200 theoretical stages above the intermediate evaporator. It is especially preferred if the rectification column or reaction column has 2 to 10 theoretical stages below the intermediate evaporator and 20 to 80 theoretical stages above the intermediate evaporator.

[0190] The side exhaust stream, through which the mixture from the rectification column or reaction column flows to the intermediate evaporator VZ is supplied, and the side inlet, through which the evaporated mixture from the intermediate evaporator flows. VZThe material being fed back into the respective rectification or reaction column can be positioned between the same trays of the column. However, it is also possible for the side outlet and side feed to be at different heights.

[0191] In such an intermediate evaporator V ZA can in the reaction column RR A existing, liquid raw product RP A comprising MA OR, water, ROH, MA OH are converted into the gaseous state, thus improving the efficiency of the conversion according to step (α1) of the process according to the invention.

[0192] In such an intermediate evaporator V ZB can in the reaction column RR B existing, liquid raw product RP B comprising MB OR, water, ROH, MB OH are converted into the gaseous state, thus improving the efficiency of the conversion according to step (α2) of the process according to the invention.

[0193] By arranging one or more intermediate evaporators V ZA or V ZB in the upper part of the reaction column RR A The dimensions in the lower part of the reaction column can be adjusted. RR A can be reduced. In the embodiment with at least one, preferably several, intermediate evaporators V ZA or V ZB Is it also possible to process partial streams of the ROH in liquid form in the upper part of the reaction column? RR A to supply.

[0194] In a further preferred embodiment, energy, preferably heat, is selected from at least a portion of a stream. S OA1 , S OA2 , selected especially from S OA11 , S OA12 , S OA2 , preferred selection from S OA11 , S OA2 , on the raw product RP A and, if step (α2) is performed, alternatively or additionally on the raw product RP B transmitted.

[0195] "Transfer of energy, preferably heat, from at least one part of S OA1on the raw product RP A and, if step (α2) is performed, alternatively or additionally on the raw product RP B" also includes the transfer of energy, preferably heat, from at least one stream selected from S OA11 , S OA12 , or from the electricity S OA1 before its division into S OA11 , S OA12 , on the raw product RP A and, if step (α2) is performed, alternatively or additionally on the raw product RP B It also includes the transfer of energy from a part of S OA11 , S OA1 on the raw product RP A and, if step (α2) is performed, alternatively or additionally on the raw product RP B

[0196] For this purpose, in particular a portion of the relevant electricity is selected from S OA1 , S OA2 or a heat transfer medium W 1 , on which energy was previously selected from the relevant current S OA1 , S OA2 was transmitted, at least partially via an intermediate evaporator. V ZA or V ZBdirected and the energy selected from the relevant current S OA1 , S OA2 or W 1 on the side print on RR A or RR B the extracted raw product stream is transferred, in particular in which the stream in question is selected from S OA1 , S OA2 or W 1 for heating the evaporator V ZA or V ZB is used.

[0197] Bottom evaporators are, according to the invention, located at the bottom of the respective rectification column. RD A or reaction column RR A or RR B or RR C arranged and are then referred to as " V SRD " or " V SRD' " or " V SA " or " V SA' " or " V SB " or " V SB' " or " V SC " or " V SC' " is referred to as such. In such a bottom evaporator, a [something] can be [something] in the respective column (especially reaction column). RR A or RR B ) located bottom product stream (especially S AP or S BP) and, for example, raw materials are at least partially removed from it. In the case of S AP or S BP This can result in a swamp product stream S AP* with an opposite S AP increased mass fraction of MA OR or a bottom product stream S BP* with an opposite S BP An increased mass share of MB OR will be obtained.

[0198] In step (α1) of the process according to the invention, at the lower end of the reaction column RR A a swamp product stream S AP Extensive raw material and raw material were extracted.

[0199] It is preferred that the reaction column RR A at least one sump evaporator V SA exhibits, via the swamp product stream S AP then partially directed and RAW partially removed from it, resulting in a bottom product stream S AP* with an opposite S AP An increased mass fraction of MA OR will be obtained.

[0200] In another preferred embodiment, therefore, for the transfer of energy, preferably heat, at least a portion of a current is selected from S OA1 , S OA2 , selected especially from S OA11 , S OA2 , on the raw product RP A and, if step (α2) is performed, alternatively or additionally on the raw product RP B The procedure is as follows: In particular, a portion of the relevant stream is selected from S OA1 , S OA2 or a heat transfer medium W 1 , on which energy was previously selected from the relevant current S OA1 , S OA2 was transferred, at least partially via a sump evaporator V SA or V SB directed and the energy selected from the relevant current S OA1 , S OA2 or W 1 on the swamp product stream S AP or S BP transferred, in particular in which the current in question is selected from S OA1 , S OA2 or W 1 for heating the evaporator V SA or V SBis used.

[0201] The mass fraction of MA OR of the bottom product stream S AP* This is particularly in relation to the mass fraction of MA OR of the bottom product stream. S AP increased by at least 0.5%, preferably by ≥ 1%, more preferably by ≥ 2%, and even more preferably by ≥ 5%.

[0202] Preferably S AP or, if at least one sump evaporator V SA is used, through which the sump product stream S AP at least partially conveyed and raw material is at least partially removed from it. S AP* , a mass fraction of MA OR in ROH in the range of 1 to 50 wt.%, preferably 5 to 35 wt.%, more preferably 15 to 35 wt.%, most preferably 20 to 35 wt.%, in each case based on the total mass of S AP .

[0203] The mass fraction of residual water in S AP or S AP*The percentage is preferably < 1 wt.%, preferably < 0.8 wt.%, more preferably < 0.5 wt.%, based on the total mass of S AP .

[0204] The mass fraction of reactant MA OH in S AP or S AP* The percentage is preferably < 1 wt.%, preferably < 0.8 wt.%, more preferably < 0.5 wt.%, based on the total mass of S AP . 4.2.2 Schritt (α2) (optional) .

[0205] Step (α2) is an optional embodiment of the method according to the invention. This means that, in the preferred embodiment of the method according to the invention, step (α2) is either performed or not. In the optional step (α2), a reactant current is introduced simultaneously with and spatially separated from step (α1). S BE1 comprehensive ROH with a reactant current S BE2 comprehensive MB OH in countercurrent flow in a reactivation column RR B to a raw product RP B comprehensive implementation of MB OR, water, ROH, MB OH.

[0206] In step (α2) of the inventive method, at the lower end of RR B a swamp product stream S BP Extensively raw and MB OR extracted. At the upper end of RR B A stream of vapors will form S BB Extensive water and ROH extraction.

[0207] MB is selected from sodium, potassium, and preferentially potassium.

[0208] The reactant current S BE1 includes raw material. In a preferred embodiment, the mass fraction of raw material is in S BE1 at ≥ 95 wt.%, even more preferably at ≥ 99 wt.%, wherein S BE1 otherwise contains, in particular, water.

[0209] The reactant current in step (α2) of the inventive method S BE1 The alcohol used in ROH can also be commercially available alcohol with an alcohol mass fraction of more than 99.8 wt.% and a water mass fraction of up to 0.2 wt.%.

[0210] The reactant current S BE1 is preferably added in vapor form.

[0211] The reactant current S BE2 MB OH includes. In a preferred embodiment, it includes S BE2 In addition to MB OH, at least one other compound selected from water, ROH. Even more preferably, comprising S BE2 besides MB OH water, then it is a matter of S BE2 to obtain an aqueous solution of MB OH.

[0212] If the reactant current S BE2 The mass fraction of MB OH, relative to the total weight of the aqueous solution, which comprises MB OH and water, is S BE2 forms, in particular in the range of 10 to 75 wt.%, preferably from 15 to 54 wt.%, more preferably from 30 to 53 wt.% and most preferably from 40 to 52 wt.%.

[0213] If the reactant current S BE2 The mass fraction of MB OH in ROH, relative to the total weight of the solution, is 1.5%. S BE2forms, in particular in the range of 10 to 75 wt.%, preferably from 15 to 54 wt.%, more preferably from 30 to 53 wt.%, and most preferably from 40 to 52 wt.%.

[0214] In the special case where the reactant current S BE2 In addition to MB OH, which includes both water and ROH, it is particularly preferred that the mass fraction of MB OH in ROH and water, based on the total weight of the solution, which S BE2 forms, in particular in the range of 10 to 75 wt.%, preferably from 15 to 54 wt.%, more preferably from 30 to 53 wt.%, and most preferably from 40 to 52 wt.%.

[0215] Step (α2) of the process according to the invention is carried out in a reactivation column (or "reaction column") RR B carried out. Preferred embodiments of the reaction column RR B are described in section 4.2.1.

[0216] "Conversion of a reactant current S BE1 comprehensive ROH with a reactant current S BE2"comprising MB OH in countercurrent" is ensured in particular by the fact that the inlet point of at least a part of the reactant current S BE1 comprehensively RAW in step (α2) at the reaction column RR B below the point where the reactant current enters the building S BE2 comprehensive MB OH lies. The reaction column RR B preferably comprises at least 2, in particular 15 to 40 theoretical stages between the point where the reactant current enters the circuit S BE1 and the point where the reactant current enters the building S BE2 .

[0217] The reaction column RR B It can be operated as a pure stripping column. Then, in the lower section of the reaction column... RR B The reactant current is vaporous. S BE1 Comprehensive raw material is supplied. Step (α2) of the process according to the invention also includes the case where part of the reactant current is supplied. S BE1 comprehensively, raw materials are located below the point where the reactant current enters the building. S BE2comprehensive alkali hydroxide MB OH, but nevertheless at the top end or in the area of ​​the top end of the reaction column RR B is added in vapor form. This allows for the dimensions in the lower section of the reaction column to be adjusted. RR B will be reduced. If part of the reactant current S BE1 comprehensively RAW, namely methanol, at the top end or in the area of ​​the top end of the reaction column RR B If, in particular, the alcohol is added in vapor form, only a partial amount of 10 to 70 wt.%, preferably 30 to 50 wt.% (in each case based on the total amount of the alcohol ROH used in step (α2)) is present at the lower end of the reaction column. RR B fed in and the remaining subset distributed in a single stream or across several substreams, preferably 1 to 10 theoretical stages, particularly preferably 1 to 3 theoretical stages below the feed point of the reactant stream. S BE2 MB OH was added in vapor form.

[0218] In the reaction column RR B The reactant current then continues S BE1 comprehensively raw material with the emulsifier current S BE2 comprehensive MB OH according to the reaction described above <1> to MBOR and H₂O, whereby, since this is an equilibrium reaction, these products are present in mixture with the reactants ROH and MBOH. Accordingly, in step (α2) of the process according to the invention, in the reaction column RR B a raw product RP B received, which includes not only the products MB OR and water, but also ROH and MB OH.

[0219] At the lower end of RR B One then obtains and extracts the swamp product stream S BP comprehensive ROH and MB OR.

[0220] At the top end of RR B , preferably at the column head of RR B , one extracts the alcohol stream still containing water, referred to above as "brew stream". S BB encompassing water and raw materials."

[0221] In step (β) of the method according to the invention, at least a part of this vapor stream is S BB including water and raw material, especially as a mixture G in step (a) of the inventive method. There, it is used with S AB mixed or not, i.e., separate from S AB as a mixture G the rectification column RD A supplied. The vapor streams are preferred. S BB and S AB mixed and then the mixture as a mixture G used in step (a) of the method according to the invention.

[0222] The amount of the reactant current S BE1 The included alcohol ROH is preferably selected such that it simultaneously serves as a solvent for the substance in the bottoms product stream. S BP The resulting alkali alkoxide MB OR serves as the basis. Preferably, the amount of alcohol ROH in the reactant stream is S BE1chosen so that the desired concentration of the alkali alkoxide solution is present in the bottom of the reaction column, which is then used as the bottom product stream. S BP Comprehensive raw materials and MB OR are extracted.

[0223] In a preferred embodiment of the method according to the invention, and particularly in cases where S BE2 In addition to MB OH, which also includes water, the ratio of the total weight (mass; unit: kg) in step (α2) as reactant current is S BE1 The amount of raw alcohol used is added to the total weight (mass; unit: kg) in step (α2) as a reactant current. S BE2 MB OH used 4 : 1 to 50 : 1, preferred 8 : 1 to 48 : 1, even more preferred 10 : 1 to 45 : 1, and still more preferred 20 : 1 to 40 : 1.

[0224] The reaction column RR B It is operated with or without, preferably with, return flow.

[0225] "With reflux" means that the reaction column is located at the top of the respective column, in step (α2) of the reaction column. RR B , extracted vapor stream S BB comprehensive water and raw material are not completely removed, i.e., in step (β) of the process according to the invention, they are not completely removed as a mixture. G is used in step (a), i.e. the rectification column RD A is supplied, but at least partially, preferably partially, again as reflux from the respective column, in step (α2) of the reaction column RR B , is supplied. In cases where such a return flow is set, the return ratio is preferably 0.01 to 0.99, more preferably 0.02 to 0.9, even more preferably 0.03 to 0.34, particularly preferably 0.04 to 0.27 and most particularly preferably 0.05 to 0.24.

[0226] In the embodiment in which the reaction column RR B If a return flow is set, the current in step (α2) can be used as the reactant current. S BE2 The MB OH used should also be at least partially mixed with the return flow and the resulting mixture should be fed to step (α2).

[0227] The optional step (α2) is carried out particularly at a temperature in the range of 45 °C to 150 °C, preferably 47 °C to 120 °C, more preferably 60 °C to 110 °C, and at a pressure of 0.5 bar abs. to 40 bar abs., preferably in the range of 0.7 bar abs. to 5 bar abs., more preferably in the range of 0.8 bar abs. to 4 bar abs., more preferably in the range of 0.9 bar abs. to 3.5 bar abs., and even more preferably at 1.0 bar abs. to 3 bar abs.

[0228] The reaction column RR B In a preferred embodiment, it comprises at least one evaporator, which in particular consists of intermediate evaporators. V ZB and sump evaporators V SB is selected. The reaction column RR B preferably includes at least one sump evaporator V SB .

[0229] In such an intermediate evaporator V ZB can in the reaction column RR B existing, liquid raw product RP B comprising MB OR, water, ROH, MB OH are converted into the gaseous state, thus improving the efficiency of the conversion according to step (α2) of the process according to the invention.

[0230] By arranging one or more intermediate evaporators V ZB in the upper part of the reaction column RR B The dimensions in the lower part of the reaction column can be adjusted. RR B can be reduced. In the embodiment with at least one, preferably several, intermediate evaporators V ZB Is it also possible to process partial streams of the ROH in liquid form in the upper part of the reaction column? RR B to supply.

[0231] In step (α2) of the process according to the invention, at the lower end of the reaction column RR B a swamp product stream S BPExtensive ROH and MB OR extraction.

[0232] It is preferred that the reaction column RR B at least one sump evaporator V SB exhibits, via the swamp product stream S BP then is at least partially directed and RAW is at least partially removed from it, resulting in a bottom product stream S BP* with an opposite S BP An increased mass share of MB OR will be obtained.

[0233] The mass fraction of MB OR of the bottom product stream S BP* This is particularly in relation to the mass fraction of MB OR of the bottom product stream. S BP increased by at least 0.5%, preferably by ≥ 1%, more preferably by ≥ 2%, and even more preferably by ≥ 5%.

[0234] Preferably S BP or, if at least one sump evaporator V SB is used, through which the sump product stream S BP at least partially conveyed and raw material is at least partially removed from it. S BP*, a mass fraction of MB OR in ROH in the range of 1 to 50 wt.%, preferably 5 to 35 wt.%, more preferably 15 to 35 wt.%, most preferably 20 to 35 wt.%, in each case based on the total mass of S BP .

[0235] The mass fraction of residual water in S BP or S BP* The percentage is preferably < 1 wt.%, preferably < 0.8 wt.%, more preferably < 0.5 wt.%, based on the total mass of S BP .

[0236] The mass fraction of reactant MB OH in S BP or S BP* The percentage is preferably < 1 wt.%, preferably < 0.8 wt.%, more preferably < 0.5 wt.%, based on the total mass of S BP .

[0237] In embodiments of the present method in which step (α2) is also carried out, the bottom product stream is preferably used. S AP at least partially via a sump evaporator V SA directed and RAW from S APat least partially removed, resulting in a swamp product stream S AP* with an opposite S AP increased mass fraction of MA OR is obtained and / or, preferably, the bottom product stream S BP at least partially via a sump evaporator V SB directed and RAW from S BP at least partially removed, resulting in a swamp product stream S BP* with an opposite S BP An increased mass share of MB OR will be obtained.

[0238] In the embodiments of the present invention in which it is carried out, step (α2) of the process according to the invention is performed simultaneously with and spatially separated from step (α1). The spatial separation is achieved by performing steps (α1) and (α2) in the two reaction columns. RR A and RR B guaranteed.

[0239] In an advantageous embodiment of the invention, the reaction columns RR A and RR Bhoused in a column casing, the column being at least partially subdivided by at least one partition wall. Such a column having at least one partition wall is called a " TRD "designated. Such partition wall columns are known to those skilled in the art and are described, for example, in US 2,295,256, EP 0 122 367 A2, EP 0 126 288 A2, WO 2010 / 097318 A1 and by I. Dejanović, Lj. Matijašević, Ž. Olujić, Chemical Engineering and Processing 2010, 49, 559-580. CN 105218315 A also describes partition columns used in the rectification of methanol.

[0240] In the columns suitable for the process according to the invention, the partition walls preferably extend to the bottom and span, in particular preferably, at least one quarter, more preferably at least one third, more preferably at least half, more preferably at least two-thirds, and even more preferably at least three-quarters of the column lengthwise. They divide the column into at least two reaction chambers in which spatially separated reactions can take place. The reaction chambers created by the at least one partition wall can be of the same or different sizes.

[0241] In this embodiment, the sump product streams can be separated in the areas by the partition wall. S AP and S BP can be extracted separately and preferably via the bottom evaporator provided for each reaction chamber formed by the at least one reaction wall V SA or V SBbe routed through which RAW from S AP or S BP is at least partially removed, thereby S AP* or S BP* will be obtained.

[0242] In a preferred embodiment of the method according to the invention, at least two, and even more preferably exactly two, of the columns are selected from the rectification column. RD A , reaction column RR A and, if step (α2) is carried out, the reaction column RR B housed in a column shell, the columns being at least partially separated from each other by a partition extending to the bottom of the column.

[0243] In combination of reaction column RR A (or in embodiments in which step (α2) is carried out, reaction column RR A and reaction column RR B ) with rectification column RD A In the process according to the invention, the rectification column RD Apreferably operated at a pressure chosen such that the pressure gradient between the columns is small.

[0244] In the process according to the invention, the raw alcohol (ROH) is consumed, and particularly in continuous processes, it must therefore be replaced with fresh raw alcohol (ROH). The fresh raw alcohol (ROH) is supplied, in particular, directly as a reactant stream. S AE1 comprehensively RAW in the reaction column RR A or in embodiments in which step (α2) is carried out, into the reaction columns RR A and RR B .

[0245] In the inventive method, it is further preferred to include the ROH-comprising vapor stream S OA partly as reactant current S AE1 in step (α1) and, if necessary, as reactant current S BE1 to be used in step (α2). Alternatively or additionally, the compressed vapor stream can be used S OA1 partly as reactant current S AE1in step (α1) and, if necessary, as reactant current S BE1 in step (α2). In this preferred embodiment, it is even more preferred if the fresh alcohol ROH is taken from the rectification column. RD A is admitted.

[0246] When the fresh RAW alcohol is processed by the rectification column RD A If it is added, it is preferably either in the rectification section of the rectification column. RD A or directly at the head of the rectification column RD A supplied. The optimal inlet point depends on the water content of the fresh alcohol used and, on the other hand, on the desired residual water content in the vapor stream. S OA The higher the water content in the alcohol used and the higher the purity requirement in the vapor stream S OA The more favorable the feed is, the more advantageous a feed several theoretical stages below the head of the rectification column. RD AUp to 20 theoretical stages below the head of the rectification column are preferred. RD A and in particular 1 to 5 theoretical levels.

[0247] When the fresh RAW alcohol is processed by the rectification column RD A When added, it is heated at temperatures up to the boiling point, preferably at room temperature, at the top of the rectification column. RD A Admittedly, a separate inlet can be provided for the fresh alcohol, or a portion of the alcohol can be returned from the head of the rectification column. RD A The extracted alcohol is mixed with this after condensation and together fed into the rectification column. RD A be supplied. In this case, it is particularly preferred if the fresh alcohol is placed in a condensate container in which the vapor stream is collected. S OA Condensed alcohol is collected and added.

[0248] As described above, in an advantageous embodiment of the invention at least two of the columns are selected from a rectification column. RD A , reaction column RR A and, if step (α2) is carried out, the reaction column RR B The columns are housed in a column jacket, with each column being at least partially separated from the others by a partition extending to the bottom of the column. In the preferred embodiment described above, in which step (α2) is carried out, they are therefore separated from the others by two partitions, the two partitions extending to the bottom of the column.

[0249] In this preferred embodiment, in particular, in a part of the TRD the reaction to the raw product RP A according to step (α1) or the raw materials RP A and RP B carried out according to steps (α1) and (α2), wherein the reactant current S AE2and, if applicable, the reactant current S BE2 although it is added below, but approximately at the level of the upper end of the partition, and the reactant current S AE1 and, if applicable, the reactant current S BE1 The alcohol / water mixture is introduced in vapor form at the lower end. The resulting alcohol / water mixture, formed above the feed point, then spreads across the entire column section above the partition, which serves as the rectification section of the distillation column. RD A The second or third lower part of the column, separated by the partition wall, serves this purpose. This is the stripping section of the rectification column. RD A The energy required for distillation is then supplied via an evaporator at the lower end of the second part of the column separated by the partition wall, whereby this evaporator can be heated conventionally or with a portion of the compressed vapor stream. S OA2It can be heated. If the evaporator is heated conventionally, an additional intermediate evaporator can be provided, which uses a portion of the compressed vapor stream. S OA1 It is heated.

[0250] In the embodiments in which a part of S OA as reactant current S AE1 and / or reactant current S BE1 is used S OA especially with a first compressor VD AB2 is compressed ("pre-compressed"), thereby reducing the difference in pressures within the reaction columns RR A and RR B compared to the pressure in RD A can be taken into account.

[0251] Alternatively or additionally, in this preferred embodiment, instead of the compressor, VD AB2 , the rectification column RD A downstream and in which S OA pre-compacted, one of the rectification columns RD A upstream compressor VD AB1be used, through which the mixture G, before it in RD A is being guided, is being guided.

[0252] The rest, especially not as reactant current S AE1 and / or reactant current S BE1 used part of the at least one vapor stream S OA will, unless it is a return to RD A is returned, in this preferred embodiment then further to S OA1 compressed. According to the invention, from S OA only in that compressor stage S OA1 , according to which the division of S OA1 in S OA1 and S OA1 This compaction, which is used in step (d) according to the invention, takes place. S OA in S OA1 Compressed, is shown in the illustrations and examples with the compressor. VD 1 (in the illustrations with <401> (designated) carried out. 4.2.3 Schritt (β) .

[0253] In step (β) of the method according to the invention, at least a part of the vapor stream is S AB , and, when step (α2) is performed, at least a part of the vapor stream S BB , mixed with S AB or separately from S AB , as a mixture G in step (a) of the method according to the invention. When step (α2) is carried out, it is preferred if at least a part of the vapor stream is used. S AB , and at least part of the Brüden stream With BB be mixed and then as a mixture G in step (a) of the method according to the invention.

[0254] "As a mixture G in step (a) of the method according to the invention" means in particular that the two streams S AB and With BB into the rectification column RD A They are directed, preferably after being mixed beforehand.

[0255] Alternatively, they can also enter the rectification column at two different inlets. RD A be guided. 4.3 Behavior Aspects: Formation by Alcoholization of Alkalimetallal Alcoholates

[0256] In an advantageous embodiment of the present invention, the energy contained in at least one of the streams is S OA1 , S OA2 , S OA11 , S OA12 This includes the energy used for operating other industrial processes. This is particularly advantageous in integrated sites (chemical parks, technology parks) where there is a constant demand for heating. This energy can be used to advantage, especially in integrated facilities with multiple plants for alkali metal alcoholate production. Such integrated facilities typically also include processes for alcoholization, as described in DE 27 26 491 A1. US 3,418,383 A describes processes for alcoholization from methanates to propylates.

[0257] In a preferred aspect of the present invention, the process according to the present invention involves a reactivation column RR C a reactant current With CE1 comprising M c OR' and optionally R'OH with a reactant current With CE2 including R"OH in countercurrent to a crude product RP C comprehensively implemented MC OR" and R'OH where at the lower end of RR C a swamp product stream S CP comprehensive MC OR" is taken from and at the upper end of RR C a stream of vapors With CB comprehensively R'OH is extracted, wherein R' and R" are two different C1 to C6 hydrocarbon residues, and MC is a metal selected from sodium, potassium, preferably sodium, and wherein energy is extracted from at least a part of a stream selected from S OA1 , S OA2 on the raw product RP C is transferred.

[0258] The process according to the preferred aspect of the invention is one for the conversion of a given alkali metal alcoholate M c OR' to another alkali metal alcoholate M c OR", as described, for example, in DE 27 26 491 A1.

[0259] R' and R" are two different C 1 to C 6 hydrocarbon residues, preferably two different C 1 to C 4 hydrocarbon residues.

[0260] Even more preferred is R' methyl and R" a C 2 to C 4 hydrocarbon residue, even more preferred is R' = methyl and R" = ethyl.

[0261] The process according to the preferred aspect of the invention (hereinafter also referred to as "re-alcoholization") is carried out in a re-rectification column. RR C carried out. Suitable reactivation columns are those described in section 4.2.1 in the context of step (α1) for RR A are described.

[0262] The reaction column RR C It is operated with or without, preferably with, a return flow. If a return flow is set up, the vapors are particularly affected. With CB partially or completely via a capacitor K PRC directed, and the condensed vapor can then return to the reaction column RR C be supplied or as reactant current S AE1 or With BE1 , It can also be used as fresh alcohol in electricity. RD A be used.

[0263] During alcohol re-entrivalization, at the lower end of RR C a swamp product stream S CP comprehensively taken from MC OR". At the top end of RR C A stream of vapors will form With CB R'OH was extracted comprehensively.

[0264] As reactant current With CE1comprising M c OR' and optionally R'OH, preferably in embodiments of the alcoholization process in which the process for producing an alkali metal alcoholate according to the invention is also carried out, at least a portion of S AP This is used, particularly since R = methyl, which then also means that R' = methyl. R" = ethyl is particularly preferred. Therefore, an alcoholization of alkali metal methoxide to the corresponding alkali metal ethoxide takes place.

[0265] As reactant current With CE1 comprising M c OR' and optionally R'OH, in a preferred alternative in embodiments of the alcoholization process in which the process for the production of an alkali metal alcoholate including step (α2) according to the invention is also carried out, preferably at least a part of S BPThis is used, particularly since R = methyl, which then also means that R' = methyl. R" = ethyl is particularly preferred. Therefore, an alcoholization of alkali metal methoxide to the corresponding alkali metal ethoxide takes place.

[0266] If S BP and S AP comprising the same alkali metal alcoholate and the same alcohol ROH, these two streams can also be separated or mixed as With CE1 be used, that is to say in particular first mixed and then the column RR C as reactant current With CE1 be directed to or separately from the column RR C as two reactant currents With CE1 be forwarded.

[0267] The reactant current With CE2 R"OH comprises. In a preferred embodiment, the mass fraction of R"OH is in With CE2 at ≥ 85 wt.%, preferably at ≥ 90 wt.%, wherein With CE2 otherwise, in particular, MC OR" or another denaturant. The reactant current With CE2 The alcohol used, R"OH, can also be commercially available alcohol with an alcohol mass fraction of more than 99.8 wt.% and a water mass fraction of up to 0.2 wt.%.

[0268] "Conversion of a reactant current With CE1 comprising M c OR' and optionally R'OH with a reactant current With CE2 According to the invention, the inclusion of R"OH in countercurrent flow is ensured in particular by ensuring that the inlet point is at least part of the reactant flow. With CE1 comprehensive M c OR'an of the reaction column RR C above the point where the reactant current enters the building With CE2 comprehensive R"OH lies.

[0269] The reaction column RR C It is operated with or without, preferably with, return flow.

[0270] The reaction column RR C In a preferred embodiment, it comprises at least one evaporator, which in particular consists of intermediate evaporators. V ZC and sump evaporators V SCis selected. The reaction column RR C preferably includes at least one sump evaporator V SC .

[0271] In the case of the reaction column RR C During intermediate evaporation, at least one side stream is produced. S ZC out of RR C extracted ("withdrawn") and the at least one intermediate evaporator V ZC supplied.

[0272] In the case of the reaction column RR C During sump evaporation, at least one stream, for example, is used. S CP out of RR C withdrawn ("deducted") and at least a part, in the case of S CP preferably a part to which at least one sump evaporator is attached V SC supplied.

[0273] Suitable evaporators that can be used as intermediate evaporators and sump evaporators are described in section 4.2.1.

[0274] In alcohol conversion, energy, preferably heat, is selected from at least a portion of a stream. S OA1 , S OA2 on the raw product RP C This is preferably done by extracting energy from at least one part of a current selected from S OA1 , S OA2 on With CE1 or With CE2 before they go RR C be directed, transmitted, and then from With CE1 or With CE2 on the in RR C existing raw product RP C , with which they mix, is transmitted.

[0275] Accordingly, energy, preferably heat, is selected from at least one part of a power supply. S OA1 , S OA2 , in particular selected from at least one stream S OA11 , S OA12 , S OA2 , preferably selected from at least one stream With OA11 , a part of S OA2 on the raw product RP C transmitted.

[0276] "Transfer of energy, preferably heat, from at least one part of S OA1on the raw product RP C "also includes the transfer of energy, preferably heat, from at least one stream selected from S OA11 , S OA12 , Electricity S OA1 before its division into S OA11 , S OA12 , on the raw product RP C .

[0277] In addition, raw product can also be used. RP C via an intermediate evaporator V ZC or a sump evaporator V SC be guided and in V ZC or V SC Energy, preferably heat, selected from at least one part of a stream S OA1 , S OA2 on the raw product RP C be transferred.

[0278] In addition, the swamp product stream can also S CP partially via a sump evaporator V SC directed and then partially re-entered RR C be traced back, whereby in V SC Energy, preferably heat, selected from at least one part of a stream S OA1 , S OA2 on the returned part of S CPis transferred and then, in the column RR C , from S CP raw product located in the column RP C is transferred.

[0279] The transfer of energy from at least a part of a current selected from S OA1 , S OA2 The aforementioned currents are affected either directly or indirectly, that is, with or without a heat transfer medium. W 1 , as described in section 4.1.4.

[0280] The preferred embodiment of the method according to the invention makes it possible to extract the energy from S OA1 , S OA2 , especially from S OA2 , S OA11 , S OA12 to use efficiently. This reduces overall energy consumption. 5. Baseball 5.1 Baseball 1 (nicht erfindungsgemäß), entspricht Abildung 1:

[0281] A stream of aqueous NaOH (50 wt%) S AE2 <102> A rate of 100 kg / h is maintained at 30 °C at the top of a reaction column. RR A <100> supplied. A vaporous methanol stream is fed in countercurrently. S AE1<103> of 1034.9 kg / h at the bottom of the reaction column RR A <100> supplied to the reaction column RR A <100> It operates at a head pressure of 2.15 bar abs. At the column sump. RR A <100> A virtually water-free product stream will be generated. S AP* <104> Extracted from 219.7 kg / h (30 wt% sodium methoxide in methanol). At the evaporator V SA <105> the reaction column RR A <100> Approximately 24 kW of heating power is supplied using low-pressure steam. This is a methanol-water vapor stream. S AB <107> is at the head of the reaction column RR A <100> extracted, of which 80 kg / h are stored in the condenser K RRA <108> condensed and returned to the reaction column RR A <100> The flow was reduced, and the remaining flow of 915.2 kg / h was fed to a rectification column. RD A <300> fed into the rectification column. RD A<300> It operates at a head pressure of 2.0 bar abs. At the bottom of the rectification column. RD A <300> A liquid water stream will be created S UA <304> Discharged at 72.2 kg / h (500 ppm wt methanol). At the top of the rectification column. RD A <300> A vaporous methanol stream is generated. S OA <302> (2 bar, 83 °C; 200 ppm water) of 1903.6 kg / h is extracted, of which 63.9 kg / h are stored in a condenser K RD <407> condenses, the remaining current is fed to a first compressor VD AB2 <303> The material is fed in and compressed there to 2.6 bar abs. The stream is then split, with a flow of 1034.9 kg / h going to the reaction column. RR A <100> The remaining 804.8 kg / h is fed into a multi-stage compression process with intercooling. In the compressor VD 1 <401> will the electricity be on p OA1 = 4.8 bar abs. and T OA1= 156 °C compressed, one obtains electricity <403> . In the subsequent intercooling in the intercooler WT X <402> The electricity is cooled to 145 °C, with approximately 4.4 kW of heat being dissipated via cooling water. In the compressor VD X <405> The current is then further compressed to 9.0 bar and 200 °C, resulting in electricity. <404> . In the following condenser, which is also the sump evaporator V SRD <406> the rectification column RD A <300> The approximately 238 kW of heating power will be used for the rectification column. RD A <300> provided. The methanol stream condensing in the process <404> is combined with 191.9 kg / h fresh methanol (1000 ppm wt water) <408> and mixed with the 63.9 kg / h of previously condensed vapors and returned to the head of the rectification column. RD A <300> abandoned.

[0282] The total compressor output is approximately 55 kW.

[0283] Together with the 24 kW for the heating steam, this results in a power requirement of approximately 79 kW for the compressor and heating steam. 5.2 Beispiel 2 (nicht erfindungsgemäß), entspricht Abildung 2:

[0284] The arrangement in Example 2, which is not according to the invention, corresponds to that according to Example 1 with the following differences: The rectification column RD A <300> features an intermediate evaporator V ZRD <409> on. The rectification column is then used. RD A <300> a fluid stream S WILL <305> extracted at 94 °C and placed in the intermediate evaporator V ZRD <409> approximately 230 kW of heat is transferred, with some of the electricity being evaporated and then returned to the rectification column. RD A <300> is supplied.

[0285] At the head of the rectification column RD A <300> A vaporous methanol stream is generated. S OA <302> (200 ppm water by weight) of 1887.1 kg / h is extracted, of which 89.4 kg / h are in a condenser K RD<407> condenses. The remaining current is compressed, as in Example 1, in a first compressor. VD AB2 <303> It is compressed to 2.6 bar abs. A partial stream of 1034.9 kg / h is then fed to the reaction column. RR A <100> The remaining 762.8 kg / h is compressed to 5.6 bar abs. and 168 °C, yielding electricity. <403> In the subsequent condenser, which also serves as the intermediate evaporator V ZRD <409> the rectification column RD A <300> The approximately 230 kW of heating power will be used for the rectification column. RD A <300> provided. The methanol stream condensing in the process <403> is combined with 191.9 kg / h of fresh methanol <408> and mixed with the 89.4 kg / h of previously condensed vapors and returned to the head of the rectification column. RD A <300> Abandoned. At the sump evaporator V SRD <406> the rectification column RD A<300> Approximately 20 kW of heating power is introduced using low-pressure steam. Compared to example 1, the vapor flow does not need to be compressed to 9 bar abs., but only to 5.6 bar abs. to transfer the heat to the evaporator. V ZRD <409> to be able to release, since the boiling temperature in the intermediate evaporator V ZRD <409> lower than in the sump evaporator V SRD <406> is.

[0286] The total compressor output is therefore only around 38 kW (instead of 55 kW), but the heating steam requirement increases to around 44 kW compared to example 1, since in the sump evaporator V SRD <406> A heating output of 20 kW is required and this is supplied using low-pressure heat.

[0287] The total power requirement for the compressor and heating steam is therefore approximately 82 kW. 5.3 Example 3 (invention measurement), corresponding to Figure 3:

[0288] The arrangement in Example 3 according to the invention corresponds to that according to Examples 1 and 2 with the following differences: At the head of the rectification column RD A <300> A vaporous methanol stream is generated. S OA <302> (200 ppm water by weight) of 1898.9 kg / h is extracted, of which 33.9 kg / h are in a condenser K RD <407> condenses. The remaining current is compressed in a first compressor, as in Example 2. VD AB2 <303> compressed to 2.6 bar abs. and then a partial stream of 1034.9 kg / h to the reaction column RR A <100> The remaining 830.1 kg / h is first compressed to 5.6 bar abs. and 169 °C, thereby generating electricity. S OA1 <403> receives a portion of this electricity. S OA11 <4031> (761.7 kg / h) is directed into a subsequent condenser, which is also the intermediate evaporator. V ZRD <409> the rectification column RD A <300> is, and approximately 230 kW of heating power for the rectification column. RD A<300> provided. The other part S OA12 <4032> (68.4 kg / h) is subsequently subjected to intermediate cooling in the intercooler WT X <402> It is cooled to approximately 154°C, with approximately 0.5 kW of heat being dissipated via cooling water. The electricity is then used. S OA12 <4032> in another compressor VD x <405> compressed, one obtains electricity S OA2 <404> with p OA2 = 9.0 bar and T OA2 = 196 °C. In the subsequent condenser, which is also the sump evaporator V SRD <406> the rectification column RD A <300> Approximately 20 kW of heating power will be required for the rectification column. RD A <300> provided. The intermediate and sump evaporators V ZRD <409> and V SRD <406> condensed methanol streams S OA11 <4031> and S OA2<404> are combined with 191.9 kg / h of fresh methanol <408> and mixed with the previously condensed 33.9 kg / h of vapors and returned to the head of the rectification column. RD A <300> abandoned.

[0289] The total compressor output is approximately 42 kW (instead of 55 kW in Example 1). Since there is no low-pressure steam for the sump evaporator... V SRD <406> As in Example 1, only around 24 kW need to be supplied by means of heating steam. The total power requirement for the compressor and heating steam thus decreases to around 66 kW.

[0290] Compared to Example 1, only a smaller vapor flow needs to be compressed to 9 bar abs., while a large portion of the vapor flow, as in Example 2, only needs to be compressed to 5.6 bar abs., thus reducing the overall compressor capacity. However, unlike Example 2, there is no low-pressure steam in the sump evaporator during steady-state operation. V SRD <406> required, so that the heating steam requirement decreases compared to example 2.

[0291] The total energy required is minimized by the method according to Example 3.

[0292] The required proportion of heating power from low-pressure steam and compressor power is in Abbildung 10 shown.

[0293] Expertise : Surprisingly, energy can be saved by using the inventive method of compressing the vapor stream in stages and thus operating the intermediate evaporator and sump evaporator with the differently compressed vapor.

Claims

1. Process for producing at least one alkali metal alkoxide of formula MAOR, wherein R is methyl, and wherein MA is a metal selected from sodium, potassium, wherein: (α1) a reactant stream SAE1 comprising ROH is reacted with a reactant stream SAE2 comprising MAOH in countercurrent in a reactive rectification column RRA to afford a crude product RPA comprising MAOR, water, ROH, MAOH, wherein a bottoms product stream SAP comprising ROH and MAOR is withdrawn at the lower end of RRA and a vapour stream SAB comprising water and ROH is withdrawn at the upper end of RRA, (α2) and optionally, simultaneously with and spatially separate from step (α1), a reactant stream SBE1 comprising ROH is reacted with a reactant stream SBE2 comprising MBOH in countercurrent in a reactive rectification column RRB to afford a crude product RPB comprising MBOR, water, ROH, MBOH, wherein MB is a metal selected from sodium, potassium, wherein a bottoms product stream SBP comprising ROH and MBOR is withdrawn at the lower end of RRB and a vapour stream SBB comprising water and ROH is withdrawn at the upper end of RRB, (β) at least a portion of the vapour stream SAB, and if step (α2) is performed at least a portion of the vapour stream SBB, in admixture with SAB or separate from SAB, is employed as mixture G in step (a) of a process for workup of a mixture G comprising water and alcohol ROH, wherein in the process for workup of a mixture G (a) the mixture G is passed into a rectification column RDA and in RDA separated into at least one vapour stream SOA comprising ROH which is withdrawn at the upper end of RDA and at least one stream SUA comprising water which is withdrawn at the lower end of RDA, (b) at least one side stream SZA is withdrawn from RDA and recycled to RDA, (c) at least a portion of SOA is compressed to afford a vapour stream SOA1 compressed relative to SOA, (d) energy is transferred from a first portion SOA11 of the compressed vapour stream SOA1 to SZA before SZA is recycled to RDA, (e) a portion SOA12 of the compressed vapour stream SOA1 that is distinct from SOA11 is subjected to further compression to afford a vapour stream SOA2 that is compressed relative to SOA11, (f) energy is transferred from at least a portion of SOA2 to at least a portion SUA1 of SUA before SUA1 is recycled to RDA.

2. Process according to Claim 1, wherein in step (d) energy is transferred from SOA11 to SZA in an intermediate evaporator VZRD.

3. Process according to Claim 1 or 2, wherein in step (f) energy is transferred from at least a portion of SOA2 to the at least a portion SUA1 of SUA in a bottoms evaporator VSRD.

4. Process according to any of Claims 1 to 3, wherein once energy has been transferred from SOA11 to SZA according to step (d) energy is transferred from SOA11 to SOA and / or once energy has been transferred from at least a portion of SOA2 to the at least a portion SUA1 of SUA according to step (f) energy is transferred from at least a portion of SOA2 to SOA.

5. Process according to any of Claims 1 to 4, wherein at least two of the columns selected from rectification column RDA, reaction column RRA and if step (α2) is performed reaction column RRB are accommodated in one column shell, wherein the columns are at least partially separated from one another by a dividing wall extending to the bottom of the column.

6. Process according to any of Claims 1 to 5, wherein a portion of SOA is employed as reactant stream SAE1 in step (α1) and if step (α2) is performed alternatively or in addition as reactant stream SBE1 in step (α2).

7. Process according to any of Claims 1 to 6, wherein energy is transferred from at least a portion of a stream selected from SOA1, SOA2 to the crude product RPA and if step (α2) is performed alternatively or in addition to the crude product RPB.

8. Process according to any of Claims 1 to 7, wherein in a reactive rectification column RRC a reactant stream SCE1 comprising McOR' is reacted in countercurrent with a reactant stream SCE2 comprising R"OH to afford a crude product RPC comprising MCOR" and R'OH, wherein a bottoms product stream SCP comprising MCOR" is withdrawn at the lower end of RRC and a vapour stream SCB comprising R'OH is withdrawn at the upper end of RRC, and wherein R' and R" are two distinct C1 to C6 hydrocarbon radicals and MC is a metal selected from sodium, potassium, and wherein energy is transferred from at least a portion of a stream selected from SOA1, SOA2 to the crude product RPC.

9. Process according to Claim 8, wherein R' = methyl.

10. Process according to Claim 9, wherein the process according to Claims 1 to 7 affords SAP, wherein R = methyl and wherein at least a portion of SAP is employed as SCE1.

11. Process according to Claim 9, wherein the process according to Claims 1 to 7 with performance of step (α2) affords SBP, wherein R = methyl and wherein at least a portion of SBP is employed as SCE1.

12. Process according to any of Claims 9 to 11, wherein R" = ethyl.