Improved process for producing alkali metal methoxides

Abstract

The present invention relates to a method for producing at least one alkali metal methoxide by reactive distillation in at least one reaction column. The respective alkali metal methoxide dissolved in methanol is removed at the bottom of the reaction column. The methanol / water mixture obtained at the top of the reaction column is separated by distillation in a rectification column. The energy of the vapor obtained at the top of the rectification column is transferred to a liquid or gaseous heat transfer medium, which is compressed in at least two stages. The energy of each compressed heat transfer medium is advantageously transferred to the bottom stream and a side stream of the rectification column. This allows for particularly energy-efficient use of the vapor energy in the process according to the invention. The energy of the compressed heat transfer medium can additionally be used for operating the reaction column or for operating a reaction column in which a process for alcohol exchange of alkali metal alkoxides is carried out.

Description

[Technical Field]

[0001] The present invention relates to a method for producing at least one alkali metal methoxide by reactive distillation in at least one reaction column. The respective alkali metal methoxide dissolved in methanol is removed at the bottom of the reaction column. The methanol / water mixture obtained at the top of the reaction column is separated by distillation in a rectification column. The energy of the vapor obtained at the top of the rectification column is transferred to a liquid or gaseous heat transfer medium, which is then compressed in at least two stages. The energy of each compressed heat transfer medium is advantageously transferred to the bottom stream and a side stream of the rectification column. This allows for particularly energy-efficient use of the steam energy in the method according to the invention.

[0002] The energy of the compressed heat transfer medium can additionally be used to operate a reaction column or columns in which a process for the alcohol exchange reaction of alkali metal alkoxides is carried out.

[0003] 1. Background of the Invention Alkali metal alkoxides are used as strong bases in the synthesis of numerous chemicals, for example in the production of pharmaceutical or agricultural active ingredients. In addition, alkali metal alkoxides are used as catalysts in transesterification and amidation reactions.

[0004] Alkali metal alkoxides (MOR, where R represents the alkyl group of the respective alcohol, in particular R=C1-C6 alkyl, advantageously methyl, ethyl, isopropyl, n-propyl) are prepared from alkali metal hydroxides (MOH) and alcohols (ROH) by reactive distillation in a countercurrent distillation column, by the following reaction: <1> [ka] The reaction water formed is removed together with the distillate.

[0005] Such a process principle is described, for example, in U.S. Pat. No. 2,877,274, in which an aqueous solution of an alkali metal hydroxide and gaseous methanol are run countercurrently in a reactive rectification column. This process is reproduced, essentially unchanged, in WO 01 / 42178.

[0006] A similar process, but in which an azeotropic agent, such as benzene, is additionally used, is described in British Patent No. 377,631 and U.S. Patent No. 1,910,331. In this case, an azeotropic agent is used to separate water from the water-soluble alcohol. In both patents, the condensate is subjected to a phase separation to separate the reaction water. A further similar process is the reaction of an alkali metal alkoxide with another alcohol in a reaction column ("alcohol exchange reaction"), described in German Patent Application No. 2,726,491.

[0007] Thus, German Patent No. 968903 describes a process for the continuous production of alkali metal alkoxides in a reaction column, in which the water-alcohol mixture withdrawn at the top is condensed and subsequently subjected to phase separation. The aqueous phase is discarded, while the alcohol phase is returned to the column at the top together with fresh alcohol. A similar process is described in European Patent Application Publication No. 0299577, in which water is separated from the condensate using a membrane. The most important alkali metal alkoxides commercially are sodium and potassium alkoxides, particularly methoxide and ethoxide. Their synthesis has been extensively described in the prior art, for example, in European Patent Application Publication No. 1997794.

[0008] In the synthesis of alkali metal alkoxides by reactive rectification as described in the prior art, a vapor containing the used alcohol and water is usually obtained. For economic reasons, it is reasonable to reuse the alcohol contained in the vapor as a starting material in reactive distillation. For this purpose, the vapor is usually fed to a rectification column, where the alcohol contained therein is separated (for example, as described in GB Patent No. 737453 and U.S. Patent No. 4,566,947). The alcohol thus recovered is then fed, for example, as a starting material to reactive distillation.

[0009] WO 2021 / 148174 and WO 2021 / 148175 describe the parallel production of different alkali metal alkoxides in separate reaction columns, with the vapors obtained in each reaction column being separated into the respective alcohol and water in a rectification column.

[0010] Alternatively or additionally, a portion of the alcohol vapor can be used to heat the rectification column (as described in WO 2010 / 097318). However, for this purpose, the vapor must be compressed to achieve the temperature level required for heating the rectification column. In particular, multistage compression of the vapor is thermodynamically advantageous. In this case, the vapor is cooled between compression stages. Furthermore, intercooling helps to prevent the maximum allowable temperature of the compressor from being exceeded. The disadvantage of this cooling, as carried out in conventional processes, is that the energy extracted in this process is dissipated rather than utilized.

[0011] Therefore, in connection with processes for producing alkali metal alkoxides, in particular where the alcohol is methanol, there is a need for an improved method for purifying alcohol / water mixtures, which method should be distinguished by particularly efficient utilization of the energy contained in the steam to operate the rectification column.

[0012] 2. Summary of the invention Thus, the present invention provides compounds of formula M A1. A process for producing at least one alkali metal methoxide of OCH3, comprising the steps of: A is selected from sodium, potassium, lithium, in particular sodium, potassium, preferably sodium.

[0013] Optionally, the formula M A Simultaneously and spatially separated from the conversion of OCH3 to alkali metal methoxide, a second reactor RR B Within the expression M B Further alkali metal methoxides of OCH3 are prepared, where M B is selected from sodium, potassium and lithium, in particular sodium and potassium, preferably potassium.

[0014] Reactor RR A or reactor RR A and R.R. B At the top of the AB Or two steam streams S AB and S BB The flow S AB Or Ryu S AB and S BB are fed individually (i.e., not mixed with each other) or mixed with each other to the rectification column RD A The methanol is separated into water and methanol by distillation. A At the top of the OA It is obtained as S OA The energy of the heat transfer medium W * 1, which is advantageously integrated into the process. The energy is S OA At least a part of the liquid or gas heat transfer medium W * 1 and W * If 1 is a liquid, it will at least partially evaporate. * Whether 1 is gas or liquid, the gas heat transfer medium W * 2 is obtained. Then, the gaseous heat transfer medium W * 2 is at least partially compressed, thereby *Compared to 2, compressed gas heat transfer medium W * 3 is obtained. W * 3 is at least two parts W * 31 and W * 32 and the energy is W * 31 From the rectification tower RD A Side flow S ZA W * 32 is further compressed, thereby * 31 Compared to compressed gas heat transfer medium W * 4 is obtained. Finally, the energy is W * From 4, RD A The flow S taken out from the bottom of UA1 and then S UA1 is RD A will be returned to.

[0015] In a further preferred embodiment, the present invention relates to a process for the alcohol exchange reaction of alkali metal alkoxides, in which the alkali metal alkoxide M c The alcohol residue of OR' is replaced by another alcohol R''OH, where R' and R'' are two different C1-C6 hydrocarbon groups, in particular R'=methyl and R''=C2-C6 hydrocarbon group, preferably R'=methyl and R''=ethyl, n-propyl, isopropyl, more preferably R'=methyl and R''=ethyl.

[0016] M c OR' is reacted with R''OH in the reaction column to form M c OR'' is formed, and W is obtained in the alcohol exchange reaction process. * 3. Especially W * 31 or W * 32 , or W * Uses 4 energy. [Brief explanation of the drawings]

[0017] [Figure 1] 1 shows a comparative process for the production of alkali metal methoxides in which distillative separation of the methanol-water mixture is not performed in accordance with the present invention. [Figure 2] A further comparative process for the production of alkali metal methoxides is shown in which distillative separation of the methanol-water mixture is not carried out according to the invention. [Figure 3] 1 illustrates an embodiment of the method according to the present invention. [Figure 4] 1 illustrates an embodiment of the method according to the present invention. [Figure 5] 2 shows a further embodiment of the method according to the invention. [Figure 6] 2 shows a further embodiment of the method according to the invention. [Figure 7] 2 shows a further embodiment of the method according to the invention. [Figure 8] 2 shows a further embodiment of the method according to the invention. [Figure 9] 1 illustrates an embodiment of a method according to the present invention. [Figure 10] 1 shows the energy savings in the method according to Example 3 compared to the method not according to the invention described in Examples 1 and 2.

[0018] 3. Figure 3.1 Figure 1 FIG. 1 shows a comparative process for the production of alkali metal methoxides in which distillative separation of the methanol-water mixture is not performed in accordance with the present invention.

[0019] In this process, aqueous NaOH S AE2 <102> Reactor RR A <100> Methanol S AE1 <103> The methanolic sodium methoxide solution is formed by reacting with the reaction column RR. A <100> At the top of the starting material stream S, an aqueous NaOH solution is added. AE2 <102> Alternatively, a methanolic aqueous NaOH solution is also added as starting material stream S AE2<102> To prepare the corresponding potassium methoxide, an aqueous or methanolic KOH solution can be added to the starting material stream S AE2 <102> Reactor RR A <100> Above the bottom of the starting material stream S AE1 <103> It is added in vapor form as

[0020] Reactor RR A <100> At the bottom of the column, a solution of the corresponding methoxide in methanol is added. AP* <104> Sodium methoxide solution S AP* <104> The concentration of A <100> The bottom evaporator V at the bottom of SA <105> and optional evaporator V SA’ <106> is set to the desired value using

[0021] Reactor RR A <100> At the top of the AB <107> is taken out. Condenser K RRA <108> Steam flow S AB <107> A part of the reaction mixture is condensed and used as reflux in the reactor RR. A <100> However, the condenser K RRA <108> The reflux amount may be set arbitrarily.

[0022] The resulting steam S AB <107> is a rectification tower or water / methanol tower RD A <300> It is supplied to the rectification column RD A <300> is the internal structure <310> The water / methanol mixture is then separated by distillation, and overhead the methanol is released as vapor S OA <302> It is recovered by distillation as

[0023] Rectification tower RD A <300> Reflux is set to steam S OA <302> Part of the condenser K RD <407> It is condensed in KRD <407> The condensation of the flow conducted through K RD <407> The steam thus condensed can then be completed in a further condenser downstream using another cooling medium (water, air). OA <302> A part of it is again sent to the rectification tower RD A <300> The remaining part, i.e. the condenser K RD <407> was not supplied to, S OA <302> Part of the compressor VD AB2 <303> Compressed by the reactor RR A <100> where the starting material stream S AE1 <103> Used as.

[0024] K RD <407> In the condenser, the energy is S OA <302> A liquid heat transfer medium W, preferably n-butane, is added from a portion of the * 1 <701> W * 1 <701> is evaporated by this, and the gaseous heat transfer medium W * 2 <702> W * 2 <702> Compressor VD1 <401> supplied to W * 2 <702> is the compressor VD1 <401> Optionally, it is additionally heated (not shown in FIG. 1) before being fed to VD1. <401> Among them, W * 2 <702> is further compressed to form a gaseous heat transfer medium flow W * 3 <703> is formed, from which the energy is transferred to an optional intercooler WT X <402> It can be discharged inside.

[0025] W * 3 <703> is the compressor VD x <405> The resulting gaseous heat transfer medium flow W * 4 <704> is used for heating the rectification column RD A <300> The evaporator V at the bottom of SRD <406> This energy release causes W * 4 <704> W again* 1 <701> Especially W * 4 <704> is at least partially condensed, thereby again forming W * 1 <701> is obtained, which then again undergoes a new cycle as above.

[0026] Fresh methanol <408> rectification column RD A <300> The reaction mixture can be fed to the process via reflux.

[0027] Rectification tower RD A <300> At the bottom of the water flow S UA <304> is obtained, which is at least partially due to the current S UA1 <320> ) Again, rectification column RD A <300> It is returned to the evaporator V SRD <406> and / or V SRD’ <410> Passing through.

[0028] 3.2 Figure 2 FIG. 2 shows a further comparative process for the production of alkali metal methoxides in which distillative separation of the methanol-water mixture is not performed according to the invention.

[0029] This embodiment corresponds to that described in FIG. 1, but with the following additional or different features: a bottom evaporator V SRD’ <406> and V SRD’ <410> In addition to the rectification tower RD A <300> is the intermediate evaporator V ZRD <409> Side flow S ZA <305> is the rectification tower RD A <300> Taken from V ZRD <409> and then passes through the rectification column RD A <300> The steam flow S OA <302> Part of the compressor VD AB2 <303> The starting material stream S is compressed by AE1 <103> As the reactor RR A <100> is recycled to

[0030] Steam S OA <302> Another part of the condenser K RD <407> and then condensed again in the rectification column RD A <300> It will be returned to K. RD <407> The condensation of the flow conducted through K RD <407> This can be completed in a further condenser downstream using another cooling medium (water, air).

[0031] Condenser K RD <407> In this case, the energy is S OA <302> A liquid heat transfer medium W, preferably n-butane, is added from a portion of the * 1 <701> W * 1 <701> is evaporated by this, and the gaseous heat transfer medium W * 2 <702> W * 2 <702> Compressor VD1 <401> where it is further compressed to form a gaseous heat transfer medium flow W * 3 <703> from which the energy is transferred to an optional intercooler WT X <402> It can be discharged inside.

[0032] Gas heat transfer medium flow W * 3 <703> For heating, an intermediate evaporator V ZRD <409> It is supplied to the evaporator V SRD <406> Medium or evaporator V SRD’ <410> W in * 3 <703> This energy release causes the * 3 <703> W again * 1 <701> Especially W * 3 <703> is at least partially condensed, thereby again forming W * 1 <701> is obtained, which then again undergoes a new cycle as above.

[0033] 3.3 Figure 3 Figure 3 shows an embodiment of the process according to the invention, in which a rectification column RD is used.A <300> is the intermediate evaporator V ZRD <409> and the bottom evaporator V SRD <406> and optionally a bottom evaporator V SRD’ <410> It has the following.

[0034] This embodiment according to the invention has the following differences with respect to the embodiment described in FIGS. 1 and 2: 1. Compressor VD1 <401> The gaseous heat transfer medium W * 2 <702> After compression, the gaseous heat transfer medium flow W * 3 <703> is made up of two parts W * 31 <7031> and W * 32 <7032> and is divided into 2.W * 31 <7031> Garyu S ZA <305> Intermediate evaporator V for heating ZRD <409> are supplied to. 3.W * 32 <7032> is the compressor VD x <405> It is further compressed and flows inside * 4 <704> In an optional embodiment, W * 32 <7032> Before being compressed, an optional intercooler WT X <402> Inside W * 32 <7032> Energy is released from W * 4 <704> Garyu S UA1 <320> For heating of the bottom evaporator V SRD <406> are supplied to. 4.W * 31 <7031> and W * 4 <704> and each evaporator V ZRD <409> Or V SRD <406> After leaving the currents and condensing, especially by releasing energy into each current, they are united and W * 1 <701> A new cycle can begin.

[0035] The difference in procedure according to the present invention and the compressed gas heat transfer medium flow W * 3 <703> Two parts W * 31 <7031> and W * 32 <7032> and W * 32 <7032> 1 and 2. * 31 <7031> Or the twice compressed flow W * 4 <704> The energy of the intermediate evaporator V ZRD <409> Or bottom evaporator V SRD <406> Through the rectification tower RD A <300> can be used more efficiently to heat the

[0036] 3.4 Figure 4 Figure 4 shows an embodiment of the process according to the invention, which corresponds to the embodiment described in Figure 3, but with the addition of a second reactor RR B <200> In aqueous KOH solution BE2 <202> Methanol S BE1 <203> It differs in that it reacts with potassium methoxide to form potassium methoxide.

[0037] Reactor RR B <200> An aqueous KOH solution is added to the top of the starting material stream S BE2 <202> Alternatively, the methanolic KOH solution is added as starting material stream S BE2 <202> It may be added as a reaction tower RR. B <200> Above the bottom of the starting material stream S BE1 <203> It is added in vapor form as

[0038] Reactor RR B <200> At the bottom of the column, a mixture of the corresponding methoxides in methanol is added. BP* <204> Potassium methoxide solution S BP*<204> The concentration of B <200> The bottom evaporator V at the bottom of SB <205> and optional evaporator V SB’ <206> is set to the desired value using

[0039] Reactor RR B <200> At the top of the BB <207> is taken out. Condenser K RRB <208> Steam flow S BB <207> A part of the reaction mixture is condensed and used as reflux in the reactor RR. B <200> However, the condenser K RRB <208> The reflux amount may be set arbitrarily.

[0040] The resulting steam S BB <207> is the condenser K RRA <108> The steam S that was not condensed in AB <107> The rectification column RD is mixed with the A <300> Alternatively, steam S AB <107> and S BB <207> and rectification tower RD separately A <300> These two feed points are preferably connected to the RD A <300> the lower half of the structure, preferably the internal structure <310> It's further down.

[0041] A further difference from the embodiment shown in FIG. AB2 <303> Steam S compressed by OA <302> The part is the reactor RR A <100> and R.R. B <200> where the starting material stream S AE1 <103> Or S BE1 <203> It is used as.

[0042] 3.5 Figure 5 Figure 5 shows a further embodiment of the method according to the invention, which corresponds to the embodiment described in Figure 4, but with W * 4 <704> Part of the Tower RR A <100> The evaporator V at the bottom of SA’ <106> and Tower RR B <200> The evaporator V at the bottom of SB’ <206> It differs in that it is also used to heat

[0043] 3.6 Figure 6 Figure 6 shows a further embodiment of the process according to the invention, which corresponds to the embodiment described in Figure 5, but in which the reactor RR A <100> and R.R. B <200> are the intermediate evaporators V ZA <110> Or V ZB <210> The difference is that it has a side flow S ZAA <111> is the reactor RR A <100> Taken from V ZA <110> and then passes through the reactor RR A <100> The side stream S ZBA <211> is the reactor RR B <200> Taken from V ZB <210> and then passes through the reactor RR B <200> is supplied again.

[0044] In contrast to Figure 5, W * 4 <704> Part of the Tower RR A <100> The evaporator V at the bottom of SA’ <106> It is used only to heat the tower RR B <200> The bottom of the evaporator V SB’ <206> In contrast, W * 31 Part of <7031> is the evaporator V ZB <210> Used to heat the

[0045] 3.7 Figure 7 Figure 7 shows a further embodiment of the process according to the invention, which corresponds to the embodiment described in Figure 5, but in which the reactor RR A <100> is the intermediate evaporator V ZA <110> The difference is that it has a side flow S ZAA <111> is the reactor RR A <100> Taken from V ZA <110> and then passes through the reactor RR A <100> In contrast to Figure 5, * 4 <704> Part of the Tower RR B <200> The evaporator V at the bottom of SB’ <206> It is used only to heat the tower RR A <100> The evaporator V at the bottom of SA’ <106> It is not used to heat the intermediate evaporator V ZA <110> The pump <501> Heat transfer medium W transported by ◆ <502> , especially heated through water, which is * 32 <7032> Intercooler WT X <402> Heat is absorbed in the intermediate evaporator V ZA <110> It releases heat inside.

[0046] 3.8 Figure 8 Figure 8 shows a further embodiment of the process according to the invention, which corresponds to the embodiment described in Figure 5, but in which the reactor RR A <100> and R.R. B <200> are the intermediate evaporators V ZA <110> Or V ZB <210> The difference is that it has a side flow S ZAA <111> is the reactor RR A <100> Taken from V ZA <110> and then passes through the reactor RR A <100> The side stream S ZBA <211> is the reactor RR B <200> Taken from V ZB <210> and then passes through the reactor RRB <200> is supplied again.

[0047] 8 shows a further preferred embodiment of the process according to the invention, which is a reactive rectification column RR for the alcohol exchange reaction of sodium methoxide to sodium ethoxide. C <600> This indicates that the current W * 32 <7032> It is at least partially powered by energy from the RR tower. C <600> is the bottom evaporator V SC <605> and V SC’ <606> It has.

[0048] In this method, sodium methoxide solution S CE1 <602> is a countercurrent reactor RR C <600> Ethanol S CE2 <603> Sodium ethoxide is formed by reacting with ethanol solution S CP <604> is extracted as

[0049] Therefore, the bottom product stream S containing sodium ethoxide CP <604> is the reactor RR C <600> It is removed at the bottom.

[0050] Steam flow S CB <607> is the reactor RR C <600> Preferably, the vapor stream S CB <607> At least a part of the condenser K RRC <608> At least a part of the condensed liquid is refluxed in the reactor RR C <600> The steam flow S CB teeth <607> is part of the condenser K RRC <608> It is extracted as a gas upstream of (shown by dashed line) and / or part of it is used in the condenser K RRC <608> Flowing downstream of <609> It is extracted as a liquid.

[0051] Side flow SZC <610> is the reactor RR C <600> The water is preferably taken from an intermediate evaporator V ZC <611> Energy is transferred through S ZC <610> is RR C <600> can be returned to.

[0052] Sodium methoxide solution S CE1 <602> Preferably, the reaction column RR A <100> and R.R. B <200> The bottom flow S obtained within AP* <104> Or S BP* <204> At least a portion of the

[0053] Bottom evaporator V SC’ <606> The pump <501> Heat transfer medium W transported by ◆ <502> , especially heated through water, which is * 32 <7032> Intercooler WT X <402> Heat is absorbed in the bottom evaporator V SC’ <606> It releases heat inside.

[0054] Alternatively, W * 31 <7031> and W * 32 <7032> W before being separated into * 4 <704> , W * 31 <7031> , W * 3 <703> From another stream selected from the bottom evaporator V SC’ <606> or a separate bottom evaporator V SC <605> Similarly, energy can be transferred to the flow W * 3 <703> , W * 31 <7031> , W * 32 <7032> , W * 4 <704> from at least one of the ethanol streams S CE1<603> , sodium methoxide solution S CE1 <602> , or side flow S ZC <610> It can also be transmitted to.

[0055] 3.9 Figure 9 Figure 9 shows an embodiment of the method according to the invention, which corresponds to the embodiment described in Figure 8, but with a bottom evaporator V SC’ <606> Heating is W * 4 <704> The difference is that it is carried out directly in part of the

[0056] 3.10 Figure 10 Figure 10 shows the energy savings for the method according to Example 3 compared to the non-inventive method described in Examples 1 and 2. The x-axis shows the respective example and the y-axis shows the applied power in MW.

[0057] The shaded portion of the bar graph represents the total compressor power output. The open portion of the bar graph represents the required heating power from the low pressure steam.

[0058] 4. Detailed Description of the Invention The present invention relates to a compound of formula M A 1. A method for producing at least one alkali metal methoxide of OCH3, wherein M A is selected from sodium, potassium, and lithium, preferably sodium and potassium, and M A is most preferably sodium.

[0059] The process according to the invention is carried out in at least one reactive rectification column, and the vapor stream obtained in the at least one reactive rectification column, which comprises methanol and water, is then at least partially separated into water and methanol in the reactive column, during which distillative separation the energy of the obtained vapor is efficiently recovered.

[0060] 4.1 Step (a1) In step (a1) of the process according to the invention, a starting material stream S AE1 , MA OH-containing starting material stream S AE2 and reactive rectification column RR A Countercurrent reaction in M A OCH3, water, methanol, M A Crude product RP containing OH A Form.

[0061] According to the present invention, a "reactive rectification column" is defined as a rectification column in which the reaction according to step (a1) or step (a2) of the process according to the present invention at least partially proceeds. It can also be abbreviated as "reaction column".

[0062] In step (a1), methanol and M A Bottom product stream S containing OCH AP RR A It is taken out at the bottom of the RR A At the top of the AB is extracted.

[0063] M A is selected from sodium, potassium, and lithium. A is in particular selected from sodium and potassium. A = sodium.

[0064] Starting material stream S AE1 In a preferred embodiment, S AE1 The mass fraction of methanol in S is ≧95% by weight, even more preferably ≧99% by weight. AE1 otherwise, especially with water.

[0065] In step (a1), the starting material stream S AE1 The methanol used as may be commercially available methanol with a mass proportion of methanol of more than 99.8% by weight and a mass proportion of water of up to 0.2% by weight.

[0066] Starting material stream S AE1 is preferably added in vapor form.

[0067] Starting material stream S AE2 is M A In a preferred embodiment, S AE2 is M A In addition to OH, it contains at least one further compound selected from water, methanol. Even more preferably, S AE2 is M A In addition to OH, it also contains water, in this case, S AE2 is M A It is an aqueous solution of OH.

[0068] Starting material stream S AE2 M A When OH and water are included, S AE2 M based on the total weight of the aqueous solution forming A The mass proportion of OH is in the range of particularly 10 to 75% by weight, preferably 15 to 54% by weight, more preferably 30 to 53% by weight, and particularly preferably 40 to 52% by weight.

[0069] Starting material stream S AE2 M A When OH and methanol are included, S AE2 M in methanol based on the total weight of the solution forming A The mass proportion of OH is in the range of particularly 10 to 75% by weight, preferably 15 to 54% by weight, more preferably 30 to 53% by weight, and particularly preferably 40 to 52% by weight.

[0070] Starting material stream S AE2 But, M A In certain cases containing both water and methanol in addition to OH, S AE2 M in methanol and water based on the total weight of the solution forming A The mass proportion of OH is particularly preferably in the range of 10 to 75% by weight, preferably 15 to 54% by weight, more preferably 30 to 53% by weight, and particularly preferably 40 to 52% by weight.

[0071] Step (a1) is a reactive rectification column (or "reaction column") RR A It will be carried out within

[0072] Step (a2) described below is carried out in a reactive rectification column (or "reaction column") RR B It will be carried out within

[0073] Preferably, the reaction column RR A Or RR B includes internals. Suitable internals are, for example, trays, structured packing or random packing. A Or RR B If reactor RR contains trays, they may be bubble cap trays, valve trays, tunnel trays, Thormann trays, cross-slit bubble cap trays or sieve trays. A Or RR B If the system includes trays, advantageously, trays are selected such that a maximum of 5% by weight of the liquid, preferably less than 1% by weight, drips through each tray. The construction measures necessary to minimize the drip flow of liquid are well known to those skilled in the art. For example, in the case of valve trays, a particularly tight valve design is selected. Furthermore, by reducing the number of valves, the vapor velocity at the tray openings can be increased to twice the value normally set. If sieve trays are used, it is particularly advantageous to reduce the diameter of the tray openings and maintain or even increase the number of openings.

[0074] When structured or random packing is used, structured packing is preferred in terms of uniform distribution of liquid.

[0075] In the case of columns with irregular packing, especially random packing, and in the case of columns with structured packing, the desired properties of liquid distribution can be achieved by reducing the liquid drip density in the edge region of the column cross section adjacent to the column shell, which corresponds to about 2-5% of the total column cross section, by up to 100%, preferably 5-15%, compared to the remaining cross section area. This can be achieved, for example, by simple means, such as by targeting the drip points of the liquid distributor or its holes.

[0076] The process according to the invention can be carried out continuously or batchwise, preferably continuously.

[0077] According to the present invention, a "methanol-containing starting material stream S AE1 and M A OH-containing starting material stream S AE2 with Countercurrent flow The "reaction" refers in particular to the reaction of the methanol-containing starting material stream S in step (a1) AE1 At least some of the feed points are A M in A OH-containing starting material stream S AE2 This is ensured by being below the supply point of

[0078] Reactor RR A is advantageously the starting material stream S AE1 The feed point and the starting material flow S AE2 At least two theoretical plates, particularly 15 to 40 theoretical plates, are included between the feed point and the column.

[0079] Reactor RR A can be operated as a pure stripping column. In this case, the starting material stream S containing methanol AE1 is vaporized in the reactor RR A is supplied to the lower region of the

[0080] Step (a1) also comprises the step of: AE1 Part of M A OH-containing starting material stream S AE2 Although it is below the feed point of the reactor RR A This includes cases where the gas is added in vapor form to the top or top region of the reactor RR. A The size of the lower region of the starting material stream S containing methanol can be reduced. AE1 A part of the reactor RR A In the upper end or upper region of the reaction column RR, in particular when added in vapor form, only a fractional amount of 10 to 70% by weight, preferably 30 to 50% by weight (in each case based on the total amount of methanol used in step (a1)) is added.A The residual quantity is introduced at the lower end of M A OH-containing starting material stream S AE2 Preferably, the feed point is 1 to 10 theoretical plates, more preferably 1 to 3 theoretical plates below the feed point, and the feed point is preferably 1 to 3 theoretical plates below the feed point.

[0081] Next, the reaction tower RR A a starting material stream S containing methanol AE1 is the above reaction <1> According to M A OH-containing starting material stream S AE2 In response, M A OCH3 and H2O are formed, and since it is an equilibrium reaction, these products are obtained from the starting materials methanol and M A OH. Therefore, in step (a1), the reaction column RR A The crude product RP A This gives the product M A In addition to OCH3 and water, methanol and M A It also contains OH.

[0082] Next, RR A At the lower end of A Bottom product stream S containing OCH AP is obtained and extracted.

[0083] RR A At the top end of the A At the top of the column, the vapor stream S containing water and methanol is AB A water-containing methanol stream, referred to as "," is removed.

[0084] In step (a3), this vapor stream S containing water and methanol is AB is at least partially A where, by distillation, at least in part, A A methanol-containing vapor stream S is taken out at the top of OA and R.D. A At least one stream S containing water is taken off at the lower end ofUA In embodiments of the invention where step (a2) is performed, the vapor stream S BB At least part of AB Mixed with or S AB Separately from the rectification tower RD A is additionally derived.

[0085] During the distillation in step (a3), stream S OA A portion of the methanol obtained in the starting material stream S AE1 As the reactor RR A can be supplied to

[0086] In a preferred embodiment of the method according to the invention, S OA A portion of the starting material stream S AE1 and if step (a2) is carried out, alternatively or additionally, starting material stream S BE1 is used in step (a2).

[0087] In a more preferred embodiment of the method according to the invention, the vapor stream S OA 5 to 95 wt. %, preferably 10 to 90 wt. %, more preferably 20 to 80 wt. %, even more preferably 30 to 70 wt. %, even more preferably 50 to 60 wt. %, even more preferably 56.7 wt. % of the starting material stream S AE1 or, if step (a2) is performed, alternatively or additionally, starting material stream S BE1 is used in step (a2).

[0088] In this preferred embodiment, the starting material stream S AE1 or starting material stream S BE1 Used as a flow OA It is advantageous to compress this portion.

[0089] Starting material stream S AE1 The amount of methanol contained by the bottom product stream S AP Alkali metal methoxide M obtained by AAdvantageously, the starting material stream S AE1 The amount of methanol in the reaction column is determined by the amount of alkali metal methoxide solution at the bottom of the reaction column, which is obtained by adding methanol and M A Bottom product stream S containing OCH AP is selected to be retrieved as

[0090] In a preferred embodiment of the method according to the invention, in particular S AE2 M A In the case where water is contained in addition to OH, in step (a1) the starting material stream S AE1 The total weight (mass; unit: kg) of methanol used as starting material stream S in step (a1) AE2 Used as M A The ratio of OH to the total weight (mass; unit: kg) is 4:1 to 50:1, more preferably 8:1 to 48:1, even more preferably 10:1 to 45:1, even more preferably 20:1 to 40:1, and even more preferably 22:1.

[0091] Reactor RR A is operated with or without reflux, preferably with reflux.

[0092] "With reflux" means that in step (a1), the reaction column RR A In optional step (a2), the reaction column RR B A vapor stream S containing water and methanol is withdrawn at the top of each of the columns. AB Or S BB In this case, in step (a3), the associated steam flow S AB Or S BB is the rectification tower RD A In step (a1), the reaction mixture is not completely introduced into the reaction column RR but is at least partially, preferably partially, introduced back into the respective column as reflux. A In optional step (a2), the reactor RR BWhen such reflux is set, the reflux ratio is preferably 0.01 to 1, more preferably 0.02 to 0.9, even more preferably 0.03 to 0.34, even more preferably 0.04 to 0.27, even more preferably 0.05 to 0.24, even more preferably 0.06 to 0.10, and even more preferably 0.07 to 0.08.

[0093] The reflux can be set by installing a condenser at the top of each column. In step (a1), the reaction column RR A Condenser K RRA In step (a2), the reactor RR B Condenser K RRB In each condenser, a respective vapor flow S AB Or S BB is at least partially condensed and in each column, in step (a1) the reaction column RR A or in step (a2), the reaction column RR B is supplied again.

[0094] Reactor RR A In the embodiment where reflux is set up in step (a1), the starting material stream S AE2 Used as M A The OH can also be at least partially mixed with the reflux stream and the resulting mixture can be fed to step (a1).

[0095] Step (a1) is especially carried out at a temperature in the range from 45°C to 150°C, preferably from 47°C to 120°C, more preferably from 60°C to 110°C, and at a pressure in the range from 0.5 bar (absolute) to 40 bar (absolute), preferably in the range from 0.7 bar (absolute) to 5 bar (absolute), more preferably in the range from 0.8 bar (absolute) to 4 bar (absolute), more preferably in the range from 0.9 bar (absolute) to 3.5 bar (absolute), even more preferably from 1.0 bar (absolute) to 3 bar (absolute), even more preferably at 1.25 bar (absolute).

[0096] Reactor RRA In a preferred embodiment, the intermediate evaporator V ZA and bottom evaporator V SA The reaction column RR includes at least one evaporator selected from the group consisting of: A is particularly preferably at least one bottom evaporator V SA Includes.

[0097] According to the present invention, the "intermediate evaporator" V Z This refers to the area above the bottom of each column, especially the reaction column RR. A Or RR B above the bottom of the ZA " or "V ZB ") or rectification column RD A above the bottom of the ZRD This refers to the evaporator located in the RR. A Or RR B In particular, the crude product RP A Or RP B is evaporated in it, and the side stream S ZAA Or S ZBA is taken out of the tower as

[0098] According to the invention, the "bottom evaporator" V S The bottom of each column, especially the reaction column RR A Or RR B or RR as used in preferred embodiments and described in more detail below. C The bottom of the SA " or "V SA’ " or "V SB " or "V SB’ " or "V SC " or "V SC’ ") or rectification column RD A The bottom of the SRD " or "V SRD’ This refers to the evaporator that heats the refrigerant (called "RR"). A Or RR B In particular, the bottom product stream S AP Or S BPAt least a portion of the RR is evaporated therein. C In particular, the bottom product stream S CP is evaporated in it. RD A In particular, the bottom product stream S UA or S UA Part of S UA1 is evaporated in it.

[0099] The evaporator is usually located outside the respective reaction or rectification column. In the evaporator, energy, in particular heat, is transferred from one stream to the other, and therefore it is a heat transfer device WT. The mixture to be evaporated is withdrawn from the column via an outlet and fed to at least one evaporator. The reaction column RR A Or RR B In the case of A Or RP B This is extracted during the intermediate evaporation of at least one intermediate evaporator V ZA Or V ZB are supplied to.

[0100] Rectification tower RD A In the case of , at least one side stream S during intermediate evaporation ZA RD A and at least one intermediate evaporator V ZRD are supplied to.

[0101] Rectification tower RD A In the case of , at least one stream S is generated during bottom evaporation. UA RD A and at least a portion, preferably a portion, is taken out ("withdrawn") from at least one bottom evaporator V SRD are supplied to.

[0102] Via at least one feed, the evaporated mixture, possibly together with residual liquid fractions, is returned to the respective column. ZA Or V ZB Or V ZRDIn this case, the outlets through which the respective mixtures are withdrawn and fed to the evaporator are side draws, and the inlets through which the evaporated mixtures are fed back to the respective columns are side draws. If the evaporator is a bottom evaporator, i.e., the column bottom is heated, that is, in particular the bottom evaporator V SA Or V SB Or V SRD When the bottom draw stream, especially S AP Or S BP At least a portion of the mixture is fed to the bottom evaporator, evaporated and returned to the respective column in the bottom region. Alternatively, however, a heat transfer medium, for example the respective compressed heat transfer medium W, can be added, for example, on a suitable tray when an intermediate evaporator is used, or at the bottom of the respective column. * 31 Or W * 4(V S Or V Z is the rectification tower RD A It is also possible to form a tube through which the heat transfer medium W1 flows (if present). In this case, evaporation takes place on the trays or at the bottom of the column. However, it is preferable to arrange the evaporator outside the respective column.

[0103] Suitable evaporators that can be used as intermediate and bottom evaporators include, for example, natural circulation evaporators, forced circulation evaporators, forced circulation flash evaporators, boiler evaporators, falling film evaporators, and thin film evaporators. For natural circulation evaporators and forced circulation evaporators, tube bundles or plate devices are usually used as heat transfer devices for the evaporators. When a tube bundle exchanger is used, a heat transfer medium, such as a rectification column RD, is used. A V in ZRD Or V SRD Compressed heat transfer medium W * 31 Or W * 4 or heat transfer medium W1 flows through the tubes and the mixture to be evaporated can flow around the tubes, or the heat transfer medium, e.g., in a rectification column RD A V in ZRD Or V SRD Compressed heat transfer medium W * 31 Or W* Either the heat transfer medium W1 or the heat transfer medium W4 flows around the tubes and the mixture to be evaporated flows through them. In the case of falling film evaporators, the mixture to be evaporated is usually added as a thin film to the inside of the tubes, which are heated from the outside. In contrast to falling film evaporators, thin film evaporators additionally have a wiped rotor, which distributes the liquid to be evaporated on the inner wall of the tubes to form a thin film.

[0104] However, any other evaporator design besides those mentioned that is known to those skilled in the art and suitable for use in a rectification column may also be used.

[0105] For example, compressed heat transfer medium W * 31 Alternatively, when the evaporator operated using the heat medium W1 as heating steam is an intermediate evaporator, the intermediate evaporator is A In the stripping section, the steam flow S AB or steam flow S BB The feed point of the reactor RR and the feed point of the reactor RR are above the bottom of the reactor. A Or RR B In the case of starting material flow S AE2 Or S BE2 It is preferred if the intermediate evaporator is located in the region between the feed point of the intermediate evaporator and the intermediate evaporator. This allows a large proportion of the heating energy to be introduced by the intermediate evaporator. For example, it is possible to introduce more than 80% of the energy via the intermediate evaporator. According to the invention, the intermediate evaporator is advantageously arranged and / or designed so that more than 10%, in particular more than 20%, of the total energy required for the distillation is introduced thereto.

[0106] When an intermediate evaporator is used, it is particularly advantageous to arrange the intermediate evaporator so that each rectification column or reaction column has 1 to 50 theoretical plates below the intermediate evaporator and 1 to 200 theoretical plates above the intermediate evaporator. It is particularly preferred when each rectification column or reaction column has 2 to 10 theoretical plates below the intermediate evaporator and 20 to 80 theoretical plates above the intermediate evaporator.

[0107] The mixture from the rectification column or reaction column is transferred to the intermediate evaporator V Z The side flow outlet that supplies the intermediate evaporator V Z The side draw and the side draw inlet, through which the evaporated mixture from the side draw is fed back into the respective rectification or reaction column, may be located between the same trays of the column. However, it is also possible for the side draw and the side draw inlet to be at different heights.

[0108] Such an intermediate evaporator V ZA So, reactor RR A Existing within M A OCH3, water, methanol, M A Liquid crude product RP containing OH A can be converted into the gaseous state, thus improving the efficiency of the reaction according to step (a1) of the method according to the invention.

[0109] Such an intermediate evaporator V ZB So, reactor RR B Existing within M B OCH3, water, methanol, M B Liquid crude product RP containing OH B can be converted into the gaseous state, thus improving the efficiency of the reaction according to step (a2) of the method according to the invention.

[0110] Reactor RR A One or more intermediate evaporators V in the upper region of ZA By placing A The dimensions of the lower region of at least one, preferably several intermediate evaporators V ZA In an embodiment comprising a reaction column RR A It is also possible to feed a partial stream of methanol in liquid form into the upper region of the column.

[0111] In a further preferred embodiment, energy, preferably heat, is transferred from at least a portion of the heat transfer medium to the crude product RP A and, if step (a2) is carried out, alternatively or additionally, the crude product RP BIn this case, the heat transfer medium is W * 2. W * 3. W * 4, preferably W * 3. W * 4, more preferably W * 3, and even more preferably W * 31 , W * 32 and even more preferably selected from W * 32 W * At least some of 3, especially W * 31 , W * 32 is selected from.

[0112] Therefore, "heat medium (in this case, the heat medium is W * 2. W * 3. W * 4) from at least a portion of the crude product RP A and, if step (a2) is carried out, alternatively or additionally, the crude product RP B "Transfer of energy, preferably heat, to * 31 , W * 32 At least one heat transfer medium selected from, or W * 31 , W * 32 before it is separated into the heat transfer medium W * Crude product RP from 3 A and, if step (a2) is carried out, alternatively or additionally, the crude product RP B It also involves the transfer of energy, preferably heat, to W * 31 , W * 32 A portion of the crude product RP A and, if step (a2) is carried out, alternatively or additionally, the crude product RP B This also includes the transfer of energy to the

[0113] To this end, in particular, * 2. W * 3. W * Part of the relevant heat transfer medium selected from 4 is the intermediate evaporator V ZA Or V ZB are derived at least in part through W * 2. W * 3. W * The relevant heat transfer medium selected from 4 is the evaporator V ZA Or V ZB The energy used to heat the * 2. W * 3. W * 4. From the relevant heat transfer medium selected from A Or RR B Optionally, in this embodiment, W * 2. W * 3. W * Heat transfer medium W different from 4 ◆ This is especially true for W ◆ is the evaporator V ZA Or V ZB First, energy, especially heat, is used to heat the * 2. W * 3. W * At least one heat transfer medium selected from W ◆ and then the energy is transferred to W ◆ From there, the RR is drawn through a side outlet. A Or RR B This means that the crude product is transferred to the crude product stream withdrawn from the

[0114] Heat medium W ◆ Any heat transfer medium known to those skilled in the art can be used as the heat transfer medium. ◆is selected from the group consisting of air, water; alcohol-water solutions; salt-water solutions (including ionic liquids such as LiBr solutions, dialkylimidazolium salts, especially dialkylimidazolium dialkylphosphates); mineral oils such as diesel oil; thermal oils such as silicone oil; biological oils such as limonene; and aromatic hydrocarbons such as dibenzyltoluene. Most preferably, the heat transfer medium W ◆ As the gas, water or air is used, particularly preferably water.

[0115] The bottom evaporator is, according to the invention, connected to each rectification column RD A or reactor RR A Or RR B Or RR C In this case, it is placed at the bottom of the SRD " or "V SRD’ " or "V SA " or "V SA’ " or "V SB " or "V SB’ " or "V SC " or "V SC’ ". Such a bottom evaporator is used in each column (especially the reaction column RR A Or RR B ) in the bottom product stream (especially S AP Or S BP ) is introduced, from which, for example, methanol can be at least partially removed. AP Or S BP In the case of S AP Compared to M A The bottom product stream S with an increased mass fraction of OCH AP* Or S BP Compared to M B The bottom product stream S with an increased mass fraction of OCH BP* can be obtained.

[0116] In step (a1) of the process according to the invention, methanol and M A Bottom product stream S containing OCH AP is the reactor RR AIt is taken out at the bottom.

[0117] Reactor RR A At least one bottom evaporator V SA and then via it the bottom product stream S AP is partially introduced and methanol is partially removed from it, thereby forming S AP Compared to M A The bottom product stream S with an increased mass fraction of OCH AP* It is preferable that

[0118] Therefore, in another preferred embodiment, the heat transfer medium (in this case the heat transfer medium is W * 2. W * 3. W * 4, preferably W * 3. W * 4, more preferably W * 4) from at least a portion of the crude product RP A and, if step (a2) is carried out, alternatively or additionally, the crude product RP B For the transfer of energy, preferably heat, to the substrate, the following procedure is carried out:

[0119] In this case, especially, W * 2. W * 3. W * 4. The part of the relevant heat transfer medium selected from the bottom evaporator V SA Or V SB are derived at least in part through W * 2. W * 3. W * The relevant heat transfer medium selected from 4 is the evaporator V SA Or V SB Energy is used to heat the * 2. W * 3. W * 4. The bottom product stream S from the relevant heat transfer medium selected from AP Or S BP is transmitted to.

[0120] Bottom product flow S AP* M A The mass proportion of OCH3 is especially AP M A It is increased by at least 0.5%, preferably ≧1%, more preferably ≧2%, even more preferably ≧5% compared to the mass proportion of OCH3.

[0121] Preferably, S AP , or at least one bottom evaporator V SA is used, via which the bottom product stream S AP is at least partially derived from which methanol is at least partially removed, S AP* is S AP Or S AP* In each case, based on the total mass of M in methanol A The mass proportion of OCH3 is in the range of 1 to 50% by weight, preferably 5 to 35% by weight, more preferably 15 to 35% by weight, and most preferably 20 to 35% by weight.

[0122] S AP Or S AP* The mass fraction of residual water in S AP Or S AP* Preferably, it is <1% by weight, preferably <0.8% by weight, more preferably <0.5% by weight, based on the total weight of the compound.

[0123] S AP Or S AP* Starting material M A The mass ratio of OH is S AP Or S AP* Preferably, it is <1% by weight, preferably <0.8% by weight, more preferably <0.5% by weight, based on the total weight of the compound.

[0124] 4.2 Step (a2) (Optional) Step (a2) is an optional embodiment of the method according to the invention, which means that in the context of a preferred embodiment of the method according to the invention, step (a2) is performed or not.

[0125] In optional step (a2), simultaneously with and spatially separated from step (a1), a methanol-containing starting material stream S BE1 , M B OH-containing starting material stream S BE2 and reactive rectification column RR B Countercurrent reaction in M B OCH3, water, methanol, M B Crude product RP containing OH B Form.

[0126] In optional step (a2) of the process according to the invention, methanol and M B Bottom product stream S containing OCH BP RR B A vapor stream S containing water and methanol is taken off at the bottom of the BB RR B It is taken out at the top of the

[0127] M B is selected from sodium, potassium, and lithium. B is in particular selected from sodium and potassium. B = Potassium.

[0128] Starting material stream S BE1 In a preferred embodiment, S BE1 The mass fraction of methanol in S is ≧95% by weight, even more preferably ≧99% by weight. BE1 otherwise, especially with water.

[0129] In optional step (a2) of the process according to the invention, the starting material stream S BE1 The methanol used as may also be commercially available methanol having a mass proportion of methanol of more than 99.8% by weight and a mass proportion of water of up to 0.2% by weight.

[0130] Starting material stream S BE1 is preferably added in vapor form.

[0131] Starting material stream S BE2 is M B In a preferred embodiment, S BE2 is M B In addition to OH, it contains at least one further compound selected from water, methanol. Even more preferably, S BE2 is M B In addition to OH, it also contains water, in this case S BE2 is M B It is an aqueous solution of OH.

[0132] Starting material stream S BE2 M B If OH and water are included, S BE2 M based on the total weight of the solution forming B The mass proportion of OH is in the range of particularly 10 to 75% by weight, preferably 15 to 54% by weight, more preferably 30 to 53% by weight, and particularly preferably 40 to 52% by weight.

[0133] Starting material stream S BE2 M B When OH and methanol are included, S BE2 M in methanol based on the total weight of the solution forming B The mass proportion of OH is in the range of particularly 10 to 75% by weight, preferably 15 to 54% by weight, more preferably 30 to 53% by weight, and particularly preferably 40 to 52% by weight.

[0134] Starting material stream S BE2 M B In certain cases containing both water and methanol in addition to OH, S BE2 M in methanol and water, based on the total weight of the solution forming B It is particularly preferable that the mass proportion of OH is in the range of 10 to 75% by weight, preferably 15 to 54% by weight, more preferably 30 to 53% by weight, and particularly preferably 40 to 52% by weight.

[0135] The optional step (a2) of the process according to the invention is to separate a reactive rectification column (or "reaction column") RR B Reactor RR BA preferred embodiment of is described in Section 4.1.

[0136] "Methanol-containing starting material stream S BE1 and M B OH-containing starting material stream S BE2 with Countercurrent flow The "reaction" according to the invention is in particular the reaction column RR B The methanol-containing starting material stream S in the optional step (a2) BE1 At least some of the supply points of M B OH-containing starting material stream S BE2 This is ensured by being below the supply point of

[0137] Advantageously, the reaction column RR B is the starting material stream S BE1 The feed point and the starting material flow S BE2 At least two theoretical plates, particularly 15 to 40 theoretical plates, are included between the feed point and the column.

[0138] Reactor RR B can be operated as a pure stripping column. In this case, the starting material stream S containing methanol BE1 is vaporized in the reactor RR B is supplied to the lower region of the

[0139] Optional step (a2) is the step of reacting a methanol-containing starting material stream S BE1 Part of M B OH-containing starting material stream S BE2 Although it is located below the feed point of the reactor RR B This also includes the case where the gas is added in vapor form to the top or top region of the reactor RR. B The size of the lower region of the starting material stream S containing methanol can be reduced. BE1 A part of the reactor RR B If the methanol is added in vapor form to the top or upper end region of the reaction column RR, then only a fractional amount of 10 to 70% by weight, preferably 30 to 50% by weight (in each case based on the total amount of methanol used in step (a2)) is added to the top or upper end region of the reaction column RR. BThe residual quantity is introduced at the lower end of M B OH-containing starting material stream S BE2 Preferably, the feed point is 1 to 10 theoretical plates, more preferably 1 to 3 theoretical plates below the feed point, and the feed point is preferably 1 to 3 theoretical plates below the feed point.

[0140] Next, the reaction tower RR B a starting material stream S containing methanol BE1 is the above reaction <1> According to M B OH-containing starting material stream S BE2 In response, M B OCH3 and H2O are formed, and since it is an equilibrium reaction, these products are obtained from the starting materials methanol and M B OH. Therefore, in optional step (a2) of the process according to the invention, the reaction column RR B The crude product RP B This gives the product M B In addition to OCH3 and water, methanol and M B It also contains OH.

[0141] Next, RR B At the lower end of B Bottom product stream S containing OCH BP is obtained and extracted.

[0142] RR B At the top end of the B At the top of the column, the vapor stream S containing water and methanol is BB A stream of methanol still containing water, called ", is removed.

[0143] In step (a3), this vapor stream S containing water and methanol is BB is at least partially A where, by distillation, at least in part, A A methanol-containing vapor stream S is taken out at the top of OA and R.D. A At least one stream S containing water is taken off at the lower end ofUA During the distillation in step (a3), the stream S OA A portion of the methanol obtained in the starting material stream S BE1 As the reactor RR B can be supplied to

[0144] In step (a3) ​​of the method according to the invention, if step (a2) is carried out, a vapor flow S BB At least part of the AB or unmixed with (in this case, S AB (separate from) rectification tower RD A Preferably, in step (a3) ​​of the method according to the invention, the vapor stream S BB and S AB and then the mixture is poured into a rectification column RD A is led to.

[0145] Starting material stream S BE1 The amount of methanol contained by the bottom product stream S BP Alkali metal methoxide M obtained by B Advantageously, the starting material stream S BE1 The amount of methanol in the reaction column is determined by the amount of alkali metal methoxide solution at the bottom of the reaction column, which is obtained by adding methanol and M B Bottom product stream S containing OCH BP is selected to be retrieved as

[0146] In a preferred embodiment of the method according to the invention, in particular S BE2 M B In the case where water is also contained in addition to OH, in optional step (a2) the starting material stream S BE1 The total weight (mass; unit: kg) of methanol used as starting material stream S in optional step (a2) BE2 Used as M BThe ratio of OH to the total weight (mass; unit: kg) is 4:1 to 50:1, more preferably 8:1 to 48:1, even more preferably 10:1 to 45:1, even more preferably 20:1 to 40:1, and most preferably 22:1.

[0147] Reactor RR B is operated with or without reflux, preferably with reflux.

[0148] Reactor RR B In the embodiment where reflux is set up at 1000° C., in optional step (a2), the starting material stream S BE2 Used as M B The OH can also be at least partially mixed with the reflux and the resulting mixture can be fed to optional step (a2).

[0149] The optional step (a2) is especially carried out at a temperature in the range from 45°C to 150°C, preferably from 47°C to 120°C, more preferably from 60°C to 110°C, and at a pressure in the range from 0.5 bar (absolute) to 40 bar (absolute), preferably in the range from 0.7 bar (absolute) to 5 bar (absolute), more preferably in the range from 0.8 bar (absolute) to 4 bar (absolute), more preferably in the range from 0.9 bar (absolute) to 3.5 bar (absolute), even more preferably from 1.0 bar (absolute) to 3 bar (absolute), most preferably at 1.25 bar (absolute).

[0150] Reactor RR B In a preferred embodiment, the intermediate evaporator V ZB and bottom evaporator V SB The reaction column RR includes at least one evaporator selected from the group consisting of: B is particularly preferably at least one bottom evaporator V SB Includes.

[0151] Such an intermediate evaporator V ZB So, reactor RR B Existing within M B OCH3, water, methanol, M B Liquid crude product RP containing OH Bcan be converted into the gaseous state, thus improving the efficiency of the conversion in optional step (a2) of the method according to the invention.

[0152] Reactor RR B One or more intermediate evaporators V in the upper region of ZB By placing B The dimensions of the lower region of at least one, preferably several intermediate evaporators V ZB In an embodiment comprising a reaction column RR B It is also possible to feed a partial stream of methanol in liquid form into the upper region of the column.

[0153] In optional step (a2) of the process according to the invention, methanol and M B Bottom product stream S containing OCH BP is the reactor RR B It is taken out at the bottom.

[0154] Reactor RR B At least one bottom evaporator V SB and then via it the bottom product stream S BP is at least partially derived and methanol is at least partially removed therefrom, thereby forming S BP Compared to M B The bottom product stream S with an increased mass fraction of OCH BP* It is preferable that

[0155] Bottom product flow S BP* M B The mass proportion of OCH3 is especially BP M B It is increased by at least 0.5%, preferably ≧1%, more preferably ≧2%, even more preferably ≧5% compared to the mass proportion of OCH3.

[0156] Preferably, S BP , or at least one bottom evaporator V SB is used, via which the bottom product stream S BPis at least partially derived from which methanol is at least partially removed, S BP* is S BP Or S BP* In each case, based on the total mass of M in methanol B The mass proportion of OCH3 is in the range of 1 to 50% by weight, preferably 5 to 35% by weight, more preferably 15 to 35% by weight, and most preferably 20 to 35% by weight.

[0157] S BP Or S BP* The mass fraction of residual water in S BP Or S BP* Preferably, it is <1% by weight, preferably <0.8% by weight, more preferably <0.5% by weight, based on the total weight of the compound.

[0158] S BP Or S BP* Starting material M B The mass ratio of OH is S BP Or S BP* Preferably, it is <1% by weight, preferably <0.8% by weight, more preferably <0.5% by weight, based on the total weight of the compound.

[0159] In embodiments of the present process in which step (a2) is also performed, preferably the bottom product stream S AP is the bottom evaporator V SA is at least partially guided via S AP Methanol is at least partially removed from S AP Compared to M A The bottom product stream S with an increased mass fraction of OCH AP* and / or preferably a bottom product stream S BP is the bottom evaporator V SB is at least partially guided via S BP Methanol is at least partially removed from S BP Compared to M B The bottom product stream S with an increased mass fraction of OCH BP* is obtained.

[0160] Step (a2) of the process according to the invention is carried out simultaneously with and spatially separated from step (a1) in the embodiment of the invention in which it is carried out. The spatial separation is achieved by separating the two reaction columns RR A and R.R. B This is ensured by performing steps (a1) and (a2) within

[0161] In an advantageous embodiment of the invention, the reaction column RR A and R.R. B are housed within a column shell, and the column is at least partially divided by at least one dividing wall. Such columns having at least one dividing wall are called "TRDs." Such dividing wall columns are known to those skilled in the art and are described, for example, in U.S. Pat. No. 2,295,256, EP 0122367, EP 0126288, WO 2010 / 097318, and I. Dejanovic, Lj. Matijasevic, Z. Olujic, Chemical Engineering and Processing 2010, 49, 559-580. CN 105218315 also describes a dividing wall column used in the rectification of methanol.

[0162] In the dividing wall column considered for the process according to the invention, the dividing wall preferably extends to the bottom, particularly preferably extending over at least one-quarter, more preferably at least one-third, even more preferably at least half, even more preferably at least two-thirds, and even more preferably at least three-quarters of the column in length. The dividing wall divides the column into at least two reaction spaces in which spatially separated reactions can take place. The reaction spaces provided by at least one dividing wall may be of the same size or of different sizes.

[0163] In this embodiment, the bottom product stream S AP and S BPcan be removed in each case in zones separated by separation walls, preferably by bottom evaporators V, which are installed for each reaction space formed by at least one reaction wall. SA or V SB can be derived via S AP or S BP Methanol is at least partially removed from S AP* Or S BP* is obtained.

[0164] Therefore, in a preferred embodiment of the process according to the invention, the rectification column RD A , reaction tower RR A and reaction column RR if step (a2) is performed. B At least two, and even more preferably exactly two, of the columns selected from are housed in the column shell, in which case the columns are at least partially separated from each other by a separating wall extending to the bottom of the columns.

[0165] In the process according to the invention, the reaction column RR A [or in the embodiment in which step (a2) is performed, reaction column RR A and reactor RR B ] and rectification column RD A In combination with the rectification tower RD A are advantageously operated at pressures selected to provide a low pressure gradient between the columns.

[0166] The process according to the invention consumes methanol which must be replaced with fresh methanol, especially in the case of continuous process operation.

[0167] In particular, the fresh methanol feed is a methanol-containing starting material stream S AE1 and the reactor RR A or in the embodiment in which step (a2) is performed, reaction column RR A and R.R. B This is done directly towards

[0168] In the process according to the invention, a vapor stream S comprising methanol is OA In step (a1), the starting material stream S AE1 and, if step (a2) is carried out, alternatively or additionally, in step (a2) the starting material stream S BE1 In this preferred embodiment, fresh methanol is used as the distillation column RD A It is even more preferred when added to

[0169] Rectification tower RD A If fresh methanol is added to the rectification column RD, it is preferably A The rectification section or rectification column RD A The optimum feed point depends on the water content of the fresh methanol used and on the other hand the vapor stream S OA The higher the water content of the methanol used, the higher the residual water content of the vapor stream S. OA The higher the purity requirement of the rectification column RD A It is convenient to feed the rectifier several theoretical plates below the top of the rectifier. A It is preferable that the column is located at a maximum of 20 theoretical plates, particularly 1 to 5 theoretical plates below the top of the column.

[0170] Fresh methanol is fed to the rectification column RD A When added to the rectification column R.D. A The fresh methanol is added at a temperature up to the boiling point, preferably at room temperature, at the top of the rectification column RD. In this case, a separate feed for fresh methanol may be provided, or fresh methanol may be added to the top of the rectification column RD. A After condensation and return of a portion of the methanol taken out at the top of the A In this case, fresh methanol can be fed into the rectification column via vapor stream S OA It is particularly preferred if the methanol condensed from the condensate is added to a condensate container where it is collected.

[0171] As described above, in an advantageous embodiment of the invention, the rectification column RD A , reaction tower RRA and the reaction column RR if step (a2) is performed. B At least two columns selected from are housed in the column shell, which are in each case at least partially separated from one another by a separating wall extending to the bottom of the column. Thus, in the above-mentioned preferred embodiment in which step (a2) is performed, they are separated from one another by two separating walls, which extend to the bottom of the column.

[0172] In this preferred embodiment, in particular a portion of the TRD, the crude product RP according to step (a1) A the crude product RP according to the reaction or steps (a1) and (a2) to obtain A and R.P. B A reaction is carried out to obtain a starting material stream S AE2 and optionally starting material stream S BE2 is added below the separator wall but at approximately the height of the top of the separator wall, and the starting material stream S AE1 and optionally starting material stream S BE1 The methanol / water mixture produced above the feed point of the starting material stream is then fed in vapor form to the rectification column RD A The second or third lower part of the column separated by the dividing wall is used as the rectifying section of the rectifying column RD. A The energy required for distillation is supplied via an evaporator at the bottom end of the second part of the column separated by a dividing wall, which can be conventionally heated or can be supplied by a compressed vapor stream S OA2 If the evaporator is conventionally heated, an intermediate evaporator can additionally be provided, which is heated by a portion of the compressed heat transfer medium, for example W * 31 or W * It is heated at 4.

[0173] S OA A portion of the starting material stream S AE1 and / or starting material stream S BE1In embodiments where S is used as OA is especially the compressor VD AB2 It is compressed with RD A Reactor RR compared to the pressure inside A and R.R. B The pressure difference within the chamber can be taken into account.

[0174] Alternatively or additionally, in this preferred embodiment, rectification column RD A connected downstream of and S OA is compressed by the compressor VD AB2 Instead of rectification column RD A Compressor VD connected upstream of AB1 You can also use AB , S BB , or S AB and S BB The mixture from each stream is A It is compressed before being introduced into the

[0175] 4.3 Step (a3)

[0176] In step (a3) ​​of the method according to the invention, a vapor stream S AB and, if step (a2) is performed, S AB Mixed with or S AB Separately from the steam flow S BB and at least a part of the A Guided by RD A Within, RD A At least one vapor stream S containing methanol is withdrawn at the top end of OA and R.D. A At least one stream S containing water is taken off at the lower end of UA and are separated into

[0177] In embodiments of the present invention in which step (a2) is performed, in step (a3), the vapor stream S AB and at least a portion of the vapor stream S BB and then mixed with at least a portion of the AAlternatively, S AB and S BB is fed into the rectification column RD at two different feed points. A You can also be guided by.

[0178] In step (a3) ​​of the method according to the invention, a vapor stream S AB and, if step (a2) is performed, S AB Mixed with or S AB Separately from the steam flow S BB and at least a part of the A Guided by RD A Within, RD A At least one vapor stream S containing methanol is withdrawn at the top end of OA and R.D. A At least one stream S containing water is taken off at the lower end of UA and are separated into

[0179] "RD A at least one vapor stream S containing methanol removed at the top end of OA " is RD A This means that the steam obtained at the top of the steam generator can be taken out there as one or more steam streams. If it is taken out there as two or more steam streams, the m steam streams are called "steam stream S" OAI ", "Vapor flow S OAII ", [...], "Steam flow S OAm " and "m" is RD A Indicates (in Roman numerals) the number of steam streams taken off at the top of the

[0180] "RD A At least one stream S containing water is taken off at the lower end of UA " is RD A This means that the water obtained at the lower end of the pipe can be taken out there as one or more streams. If it is taken out as two or more streams, the n streams are called "streams S" UAI ”, “Ryu S UAII ”, [...], “Flow S UAn " and "n" is RD AThe number of streams removed is indicated (in Roman numerals) at the bottom.

[0181] Steam flow S AB and, if step (a2) is performed, vapor stream S BB and at least a portion of the feed to the rectification column RD via one or more feed points. A They can be introduced, for example, when step (a2) is carried out in a method according to a preferred embodiment of the present invention and step (a3) ​​is carried out by introducing a vapor stream S BB At least part of AB In an embodiment where the steam flow S is used separately from the steam flow S, the steam flow S is introduced through several feed points. AB and at least a portion of the vapor stream S BB and at least a portion of the A is led to.

[0182] Steam flow S AB and, if step (a2) is performed, vapor stream S BB and at least a portion thereof are fed to the rectification column RD as two or more separate streams. A In the embodiment of the present invention where the feed points of the individual streams are directed to the rectification column RD A It is advantageous if the electrodes are at substantially the same height.

[0183] In a preferred embodiment of step (a3) ​​of the method according to the invention, the vapor stream S AB and, if step (a2) is performed, vapor stream S BB At least a part of the above is a rectification column RD A Within, RD A A methanol-containing vapor stream S is taken out at the top of OA and R.D. A A water-containing stream S is drawn off at the bottom of the UA and are separated into

[0184] Another term for the "top of the rectification column" is the "top."

[0185] Other terms for the "lower end of the rectification column" are the "bottoms" or "foot."

[0186] At least one vapor stream S OA The pressure of "p OA ” and its temperature is called “T OA This is particularly true in step (a3) ​​of the rectification column RD A At least one vapor stream S as it is withdrawn from OA is related to the pressure and temperature.

[0187] pressure p OA is in particular in the range of 0.5 bar (absolute) to 8 bar (absolute), more preferably in the range of 0.6 bar (absolute) to 7 bar (absolute), more preferably in the range of 0.7 bar (absolute) to 6 bar (absolute), even more preferably in the range of 1 bar (absolute) to 5 bar (absolute), even more preferably in the range of 1 bar (absolute) to 4 bar (absolute), even more preferably in the range of 1.0 bar (absolute) to 2.0 bar (absolute), and most preferably 1.1 bar (absolute).

[0188] 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, even more preferably in the range of 60°C to 110°C, even more preferably in the range of 65°C to 80°C, and most preferably 67°C.

[0189] The rectification column RD in step (a3) ​​of the present process A Any rectification column known to those skilled in the art can be used as the rectification column RD. Preferably, the rectification column RD Aincludes internal structures. Suitable internal structures are, for example, trays, random packings or structured packings. As trays, bubble cap trays, sieve trays, valve trays, tunnel trays or slotted trays are usually used. The random packings are generally layers of random packing. As random packings, Raschig rings, Pall rings, Berl saddles or Intalox® saddles are usually used. Structured packings are, for example, sold by Sulzer under the trade name Mellapack®. In addition to the internal structures listed above, further suitable internal structures are known to those skilled in the art and can be used as well.

[0190] Preferred internals have a low specific pressure drop per theoretical stage. For example, structured and random packings have significantly lower pressure drops per theoretical stage than trays. This advantage is especially evident in rectification column RDs. A The key is to keep the pressure loss in the compressor as low as possible, and therefore the mechanical power of the compressor and the temperature of the methanol / water mixture that is to be vaporized low.

[0191] Rectification tower RD A When structured or random packing is included within the separator, it may be divided or may be one continuous packing. However, there are usually at least two packings: 1) Preferably, - If step (a2) is not performed: S AB one filling above the feed point of; - Step (a2) is performed and S AB and S BB and then mixed with RD A If you are led to:S AB and S BB one filling above the feed point of the mixture with; - Step (a2) is performed and S AB and S BB and RD separately A If you are led to:S AB and S BBand one filling above the feed point. 2) Furthermore, preferably, - If step (a2) is not performed: S AB one filling below the feed point of; - Step (a2) is performed and S AB and S BB and then mixed with RD A If you are led to:S AB and S BB one filling below the feed point of the mixture with; - Step (a2) is performed and S AB and S BB and RD separately A If you are led to:S AB and S BB and one filling below the feed point.

[0192] S AB Or S AB and S BB There may be one packing above the feed point of S AB Or S AB and S BB There may be several trays below the feed point. When random packing, such as random packing elements, is used, the random packing is typically placed on a suitable support grid (e.g., sieve trays or mesh trays).

[0193] In each embodiment, S AB Or S AB and S BB The supply point is the tower RD A That is, in the lower half of S AB Or S AB and S BB That is, Tower RD A It is preferable that the lower half of

[0194] In step (a3) ​​of the process according to the invention, at least one vapor stream S comprising methanol is then OA is the rectification tower RD AThis vapor flow S OA The preferred mass proportion of methanol therein is ≧99% by weight, more preferably ≧99.6% by weight, even more preferably ≧99.9% by weight, the remainder being in particular water.

[0195] RD A At the lower end of the UA is removed, which may preferably have <1 wt. %, more preferably ≦5000 wt. ppm, even more preferably ≦2000 wt. ppm methanol.

[0196] In the context of the present invention, at least one vapor stream S comprising methanol OA Rectification tower RD A The withdrawal at the top of at least one vapor stream S OA However, the rectification tower RD A This means that the gas is withdrawn above the internals as an overhead stream or as a side draw.

[0197] In the context of the present invention, at least one stream S comprising water UA Rectification tower RD A The withdrawal at the bottom of the at least one stream S UA as the bottom stream or the rectification column RD A This means that the food will be picked up from the bottom tray.

[0198] Rectification tower RD A is operated with or without reflux, preferably with reflux.

[0199] "With reflux" means that the rectification column RD A The steam flow S is extracted at the top of OA is not completely discharged, but is partially condensed and redischarged into each rectification column RD A When such reflux is set, the reflux ratio is preferably 0.0001 to 10, more preferably 0.1 to 5, even more preferably 0.5 to 2, even more preferably 0.7 to 1, and even more preferably 0.76.

[0200] Reflux is the rectification column RD A Condenser K at the top of RD This can be set by installing a condenser K. RD In the vapor flow S OA is partially condensed and A The reflux ratio is generally understood in the sense of the present invention to mean the ratio of the mass flow rate (kg / h) taken off from the column that is returned to the column in liquid form (reflux) to the mass flow rate (kg / h) taken off from the respective column in liquid or gaseous form.

[0201] 4.4 Step (b) of the method according to the invention In step (b) of the method according to the invention, at least one side stream S ZA RD A taken from and again RD A will be returned to.

[0202] In a preferred embodiment of step (b) of the method according to the invention, the side stream S ZA RD A taken from and again RD A will be returned to.

[0203] According to the present invention, "RD A Side flow from S ZA " means that the flow is A The take-out point E is below the top and above the bottom of ZA In particular, additionally, RD A Supply point Z below the top and above the bottom ZA (This means that each side stream S ZA Again, the rectification tower RD A (This is the point where it is sent back to RD) A This means that the item will be returned to

[0204] This is especially true for the rectification column RD A Each side flow S ZA Extraction point E ZA , preferably also at the supply point Z ZA But, RDA All steam flows S extracted from OA Extraction point E OA Lower and RD A The steam flow S extracted from OA Extraction point E OA And the take-out point E OA is the rectification tower RD A The lowest take-out point E OA More preferably, it means at least 1, even more preferably at least 5, and even more preferably at least 10 theoretical plates below.

[0205] Moreover, this is especially true for the rectification column RD A Each side flow S ZA Extraction point E ZA , preferably also at the supply point Z ZA But, RD A All steam flows S extracted from uA Extraction point E uA It is located above the steam flow S uA Extraction point E uA And the take-out point E uA is the rectification tower RD A The highest point of removal E uA More preferably, it means above at least one theoretical plate, even more preferably at least two, and even more preferably at least four theoretical plates.

[0206] At least one vapor stream S OA is at least partially re-fed to the rectification column RD A (This is, for example, when the reflux is returned to the rectification column RD A ), in particular when at least one steam flow S OA Supply point Z OA (i.e., at least one vapor stream S OA is at least partially re-fed to the rectification column RD A The point that is returned to RD A All side streams S taken from ZA Extraction point E ZA Above, especially at supply point Z ZALocated higher than RD A All side streams S taken from ZA Preferably, the highest point of all the take-off and feed points is at least one theoretical plate above, more preferably at least five theoretical plates above, and even more preferably at least ten theoretical plates above.

[0207] At least one flow OA is at least partially re-fed to the rectification column RD A In particular, if the goods are returned to the UA Supply point Z OA (i.e., at least one flow S UA is at least partially re-fed to the rectification column RD A The point that is returned to RD A All side streams S taken from ZA Extraction point E ZA Lower, especially at supply point Z ZA Lower and RD A All side streams S taken from ZA Preferably, the lowest point of all the take-off and feed points is at least one theoretical plate below, more preferably at least two theoretical plates below, and even more preferably at least four theoretical plates below.

[0208] Rectification tower RD A Side flow S ZA Extraction point E ZA and side flow S ZA Supply point Z ZA What is RD? A However, they can also be at different heights.

[0209] In a preferred embodiment of the process according to the invention, the rectification column RD A At least one side stream S ZA Extraction point E ZA , preferably at the supply point Z ZA is also the supply point Z SAB Lower and RD A Even more preferably, the rectification column RD is located above the bottom of the rectification column RD. A At least one side stream SZA Extraction point E ZA , preferably at the supply point Z ZA Also, RD A It is also located below the rectification section.

[0210] Supply point Z SAB RD A Inside S AB All supply points of RD A Inside S BB All supply points of RD A Inside S AB and S BB This indicates the lowest feed point of all the feed points of the mixture from and.

[0211] In a particularly preferred embodiment of the process according to the invention, the rectification column RD A At least one side stream S ZA Extraction point E ZA , and more preferably also the supply point Z ZA is the supply point Z SAB Below and RD A All flows taken from S UA The rectification column RD located above the highest take-off point and feed point among all the take-off points and feed points of A Preferably, the area is in the upper 4 / 5, preferably the upper 3 / 4, preferably the upper 7 / 10, more preferably the upper 2 / 3, more preferably the upper 1 / 2.

[0212] In this case, more preferably, the rectification column RD A At least one side stream S ZA Extraction point E ZA , preferably also at the supply point Z ZA RD A It is located below the rectification section.

[0213] In a further particularly preferred embodiment of the process according to the invention, the rectification column RD A includes the rectifying section, and the rectifying column RD A At least one side stream S ZA Extraction point E ZA , and more preferably also the supply point Z ZAis located below the rectifying section and A All flows taken from S UA Rectification column RD above all take-off and feed points A Preferably, the area is in the upper 4 / 5, preferably the upper 3 / 4, preferably the upper 7 / 10, more preferably the upper 2 / 3, more preferably the upper 1 / 2.

[0214] 4.5 Step (c) of the method according to the invention In step (c) of the method according to the invention, energy, preferably heat, is added to S OA A liquid or gas, preferably a liquid heat transfer medium W * 1, whereby the gaseous heat transfer medium W * 2 is obtained.

[0215] Heat medium W * Any working medium well known to those skilled in the art can be used as the heat transfer medium W. * 1 is in particular selected from the group consisting of water, optionally fluorinated alkanes, ammonia, alcohols. * 1 is selected from n-hexane, n-pentane, n-butane, n-propane, methanol, ethanol, propanol. Most preferably, W * 1 = n-butane.

[0216] By step (c) of the method according to the invention, energy, preferably heat, is added to S OA A liquid or gas, preferably a liquid heat transfer medium W * 1, and the gaseous heat transfer medium W * 2 is obtained.

[0217] This is the heat transfer medium W * If 1 is used in liquid form in step (c), energy, preferably heat, is supplied to it in step (c), and thus the liquid heat transfer medium W * 1 is at least partially evaporated, and thus the gaseous heat transfer medium W * This means that you get 2.

[0218] " liquid Heat medium W * 1" refers in particular to the heat transfer medium W used in step (c). * Based on the total weight of 1, the heat transfer medium W used in step (c) * 1 is present in a liquid state. Preferably, the heat transfer medium W used in step (c) * Based on the total weight of 1, the heat transfer medium W used in step (c) * 1 means that ≧25 wt. %, more preferably ≧50 wt. %, more preferably ≧55 wt. %, more preferably ≧75 wt. %, more preferably ≧90 wt. %, more preferably ≧99 wt. % of 1 is present in a liquid state of matter.

[0219] In step (c) of the method according to the invention, the liquid heat transfer medium W * When 1 is used, in step (c) of the method according to the invention, in a preferred embodiment, S OA At least a part of the liquid heat transfer medium W * 1 and during step (c), the heat transfer medium W used in the liquid state * ≧10% by weight, preferably ≧20% by weight, preferably ≧30% by weight, preferably ≧40% by weight, preferably ≧50% by weight, preferably ≧60% by weight, preferably ≧70% by weight, preferably ≧80% by weight, preferably ≧90% by weight, preferably ≧99% by weight of the liquid heat transfer medium W1 is converted into a gaseous state, particularly preferably during step (c). * A sufficient amount of energy, preferably heat, is transferred so that 1 is completely converted to the gaseous state.

[0220] Alternatively, the heat transfer medium W * 1 can be used in gaseous form in step (c). In this case, energy, preferably heat, is supplied to it in step (c), and the gaseous heat transfer medium W is then used again following step (c). * 2 is obtained.

[0221] " gas Heat medium W * 1" refers in particular to the heat transfer medium W used in step (c). *This means that 1 exists entirely in a gaseous state of matter.

[0222] "Transfer of energy" means, according to the invention, in particular "heating", i.e. the transfer of energy in the form of heat.

[0223] "S OA A liquid or gas, preferably a liquid heat transfer medium W * The transfer of energy, preferably heat, to one OA But part S OA1 In some cases, this part S OA1 After compression, the methanol stream S AE1 and / or S BE1 The part S used as OA1 and part S OA2 and the reflux is A Part S to be returned to OA2 and (c) is divided into S OA2 Only from this, energy, especially heat, is * 1 is transmitted.

[0224] W * 2 is W * 1 has an increased energy content. OA The energy content of the is reduced during step (c).

[0225] S OA A liquid or gas, preferably a liquid heat transfer medium W * The transfer of energy, especially heat, to 1 is preferably direct or indirect, more preferably direct. Another term for "transfer of heat" is "heating."

[0226] "Direct" means, in particular, OA and W * 1 and S without mixing OA W * 1, and energy, especially heat, is released into the OA From W * This means moving to 1.

[0227] This can be done using methods known to those skilled in the art.

[0228] In particular, S OA and W * 1 means that energy, preferably heat, is S OA From W * 1 can be conducted through a heat transfer device.

[0229] As heat transfer device (another term for "heat transfer device" = "heat exchanger"), heat transfer devices familiar to the person skilled in the art can be used, in particular evaporators, in particular boiler evaporators, as described above (section 4.1). Preferably, boiler evaporators are used, in which W * 1 is depressurized, and then or during OA Energy is absorbed from

[0230] As described above, in a preferred embodiment of the present invention, the reflux is fed to the rectification column RD A Especially the rectification tower RD A Condenser K at the top of RD is installed, in which the steam flow S OA is partially condensed, and A is supplied again.

[0231] In this preferred embodiment, S OA From W * The direct transfer of energy, preferably heat, to the condenser K RD The advantage of this is that RD The condenser can be used as a heat transfer device at the same time, so there is no need to install an additional evaporator / condenser.

[0232] "Indirect" means, in particular, OA but preferably at least one heat transfer device WT X Through W * Heat medium W1 different from 1 ◆ In this case, the heat transfer medium W1 ◆is W * Not 1, i.e. W1 ◆ is W * Unlike 1, energy, preferably heat, is transferred to the S without the two streams mixing. OA Then, the heat is transferred to the heat medium W1 ◆ Heat transfer medium W * By contacting with 1, W1 to W * 1 ◆ In this case, W * 1 and W1 ◆ W1 means to mix or not to mix, but preferably not to mix. ◆ and W * 1 and WT 1 , the transfer of energy, preferably heat, is carried out in particular by a further heat transfer device WT 1 . Y It is held at.

[0233] In a further embodiment of the method according to the invention, S OA From W * Indirect energy transfer to 1, especially S OA by W * In the case of heating, energy, preferably heat, is first introduced into the OA From W1 ◆ , preferably at least one heat exchanger WT X and then W1 ◆ From W * Further heat transfer medium W2 different from 1 ◆ , preferably at least one heat exchanger WT Y Then, in the final step, W2 ◆ From W * Heat is transferred to the * 1 and W2 ◆ It may or may not be mixed with W2, but preferably it is not mixed with W2. ◆ and W * 1 and WT 1 , the transfer of energy, preferably heat, is carried out in particular by a further heat transfer device WT 1 . Z It is held at.

[0234] In a further embodiment of the invention, a further heat transfer medium W3 ◆, W4 ◆ , W5 ◆ It is obvious that the following can be used as appropriate.

[0235] Heat medium W1 ◆ Or other heat transfer medium W2 that is further used ◆ , W3 ◆ , W4 ◆ , W5 ◆ Any heat transfer medium known to those skilled in the art can be used as the heat transfer medium W1, and preferably they are selected from the group consisting of air; water; alcohol-water solutions; salt-water solutions (including ionic liquids such as LiBr solutions, dialkylimidazolium salts, especially dialkylimidazolium dialkylphosphates); mineral oils such as diesel oil; thermal oils such as silicone oil; biological oils such as limonene; aromatic hydrocarbons such as dibenzyltoluene. Most preferably, the heat transfer medium W1 ◆ The gas is preferably water or air, and most preferably water.

[0236] As described above, in a preferred embodiment of the present invention, the reflux is fed to the rectification column RD A Especially the rectification tower RD A Condenser K at the top of RD is installed, in which the steam flow S OA is partially condensed, and A is supplied again.

[0237] In this preferred embodiment, S OA From W * 1 or S OA From W1 ◆ The direct or indirect transfer of energy, preferably heat, to the RD This advantage is due to the fact that the condenser K RD The advantage of this is that the heat transfer device can be used simultaneously, eliminating the need for an additional evaporator / condenser.

[0238] Following step (c) of the method according to the invention, the gaseous heat transfer medium W * 2 is obtained.

[0239] W * The pressure with 2 is "p W*2 ” and its temperature is called “T W*2 "It is called "

[0240] W * The pressure with 1 is "p W*1 ” and its temperature is called “T W*1 "It is called "

[0241] In a preferred embodiment of the present invention, W * 1 is a temperature T in the range of 50°C to 170°C, more preferably 90°C. W*1 And especially W * When 1 is a gas, the pressure p is 1 bar to 35 bar, more preferably 1.5 bar to 20 bar. W*1 It has the following.

[0242] In a preferred embodiment of the present invention, W * 2 is a temperature T in the range of 25°C to 150°C, more preferably 70°C. W*2 and a pressure p of 1 bar to 35 bar, more preferably 5 bar to 8 bar, and even more preferably 6.4 bar to 6.7 bar. W*2 It has the following.

[0243] Heat medium W * 2 is heat transfer medium W * 1 and W * 2 and W * 1 and their respective pressures p W*2 Or p W*1 and / or their temperatures T W*2 Or T W*1 and possibly W * It is obvious that when 1 is used as a liquid, it differs only in terms of the state of matter.

[0244] 4.6 Step (d) of the method according to the invention In step (d) of the method according to the invention, the gaseous heat transfer medium W * At least a portion of W2 is compressed. * Compared to 2, compressed gas heat transfer medium W* 3 is obtained.

[0245] W * The pressure that 2 has is "p W*2 " and its temperature is called "T W*2 " is called.

[0246] W * The pressure on 3 is "p W*3 " and its temperature is called "T W*3 " is called.

[0247] pressure p W*3 HAp W*2 Higher than. p W*3 The exact value of p W*3 >p W*2 As long as the condition of (a) is satisfied, it can be set by a person skilled in the art according to the requirements of step (d). W*3 / p W*2 (pressure unit is in each case bar (absolute)) is preferably in the range of 1.1 to 10, more preferably 1.2 to 8, more preferably 1.25 to 7, more preferably 1.3 to 6, even more preferably 1.5 to 2, even more preferably 1.6 to 1.8, most preferably 1.7.

[0248] temperature T W*3 is especially at temperature T W*2 Higher than T W*3 / T W*2 (temperature units are °C in each case) 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, and most preferably 1.08 to 5.

[0249] p W*3 and T W*3 The preferred value of W * 31 and W * 32 The preferred pressure or preferred temperature also applies as appropriate.

[0250] The gaseous heat transfer medium W in step (d)* Compression of at least a portion of the gas W can be carried out by any method known to those skilled in the art. For example, compression can be carried out mechanically in a single stage or multiple stages, preferably multiple stages. In the case of multiple stage compression, multiple compressors of the same design or compressors of different designs can be used. Multistage compression can be carried out using one or more compressor machines. The use of single stage or multiple stage compression depends on the compression ratio and therefore the gaseous heat transfer medium W. * 2 depends on the pressure to which it must be compressed.

[0251] In the method according to the invention, the compressor is preferably a gaseous heat transfer medium W * 2 to W * 3 or W * 32 From W * Any compressor known to those skilled in the art, preferably a mechanical compressor capable of compressing a gas flow, is suitable as the compressor for compressing the gas to 4. Suitable compressors are, for example, single-stage or multi-stage turbine, piston compressors, screw compressors, centrifugal compressors or axial compressors.

[0252] In the case of multistage compression, a compressor suitable for each pressure stage to be overcome is used.

[0253] 4.7 Step (e) of the method according to the invention In step (e) of the method according to the invention, energy, in particular heat, is transferred to the gaseous heat transfer medium W * The first part of 3 W * 31 From S ZA After being transmitted to S ZA is RD A will be returned to.

[0254] In particular, gaseous heat transfer medium W * 3, in step (e), first divide at least two parts W * 31 and W * 32 and W * 31 vs. W * 32The ratio of the mass flow rate (kg / h) of the above 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, even more preferably in the range of 5:20 to 15:1, more preferably in the range of 2:1 to 5:1, even more preferably in the range of 4:1 to 4.5:1, and most preferably 4.4:1.

[0255] In step (e) of the method according to the invention, a first portion W * 31 From S ZA Step (e) transfers energy to W * 31 The energy of * 31 is at least partially condensed.

[0256] "Transfer of energy" means, according to the invention, in particular "heating", i.e. the transfer of energy in the form of heat.

[0257] "Compressed steam flow W * The first part of 3 W * 31 From S ZA "Transfer of energy to" is W * 31 A part of the energy is separated and the energy is transferred from this part only to the ZA This includes the case where additional energy is transferred to W * 31 From the crude product RP A and, if step (a2) is carried out, alternatively or additionally, the crude product RP B This is the case in the embodiment of the present invention (described in Section 4.1) where the

[0258] W * 31 From S ZA Transfer of energy to, preferably W * 31 by S ZA The heating is preferably carried out directly or indirectly.

[0259] "Direct" means that the two flows flow together without mixing. * 31 S ZA and thus energy, especially heat, is released into the * 31 From S ZA This means moving to

[0260] This is W * 31 and S ZA and rectification tower RD A Intermediate evaporator V ZRD Leading through W * 31 S ZA This can be done by heating.

[0261] As a heat transfer device (another term for "heat transfer device" = "heat exchanger"), in particular the heat transfer device WT described below X , W.T. Y , W.T. Z In step (e) of the method according to the invention, in particular the energy, preferably heat, W * 31 From S ZA Transfer to intermediate evaporator V ZRD It is carried out internally.

[0262] "Indirect" means, in particular, * 31 but preferably at least one heat transfer device WT X Through the heat transfer medium W △ 1, in which case the heat transfer medium W △ 1 is S ZA Not W, △ 1 is S ZA Unlike the W * 31 From W △ 1, and then the heat is △ 1 is flow S ZA By coming into contact with W △1 to S ZA In this case, S ZA and W △ 1 means that they may or may not be mixed, but preferably they are not mixed. △ 1 and S ZA If the two are not mixed, the transfer of energy, preferably heat, is carried out in particular by a further heat transfer device WT Y It is held at.

[0263] In a further embodiment of the method according to the invention, W * 31 From S ZA Indirect energy transfer to the * 31 by S ZA For heating, energy, preferably heat, is first calculated as W * 31 From W △ 1, preferably at least one heat exchanger WT X transmitted by contact via W △ From 1, S ZA Further heat transfer medium W △ 2, preferably at least one heat exchanger WT Y Then, in the final step, W △ 2 to S ZA In this case, heat is transferred to S ZA and W △ 2 may or may not be mixed, but preferably not mixed. △ 2 and S ZA If the two are not mixed, the transfer of energy, preferably heat, is carried out in particular by a further heat transfer device WT Z It is held at.

[0264] In a further embodiment of the invention, a further heat transfer medium W △ 3. W △ 4. W △ It is obvious that 5 etc. can be used as appropriate.

[0265] Heat medium W △ 1 or other heat transfer medium W to be used △ 2. W△ 3. W △ 4. W △ Any heat transfer medium known to those skilled in the art can be used as 5, and preferably it is selected from the group consisting of air; water; alcohol-water solutions; salt-water solutions (including ionic liquids such as LiBr solutions, dialkylimidazolium salts, especially dialkylimidazolium dialkylphosphates); mineral oils such as diesel oil; thermal oils such as silicone oil; biological oils such as limonene; aromatic hydrocarbons such as dibenzyltoluene. Most preferably, the heat transfer medium W △ 1 is water or air, even more preferably water.

[0266] Salt-water solutions which can be used are described, for example, in DE 102005028451 A1 and WO 2006 / 134015.

[0267] In a preferred embodiment, W * 31 From, especially S ZA After the transfer of energy to the

[0268] In a preferred embodiment of the method according to the invention, the energy, preferably heat, is * 31 According to step (e), ZA After transferring energy to W * 31 From S OA or S OA Part of the S supplied to the compression OA Part of S OA1 This is transmitted to S OA This allows for a pre-compression of the W * 31 The remaining energy or heat stored by the OA Or S OA Part of S OA1 It can be used to heat the

[0269] "Pre-compression" refers specifically to the first compression stage in a multi-stage compression process.

[0270] W * 31 Another preferred additional sink for energy, preferably heat, in is described below (see paragraph 4.10).

[0271] Step (e) of the method of the present invention reflects one aspect of the unexpected effect of the present invention. * Compressed gaseous heat transfer medium W * The excess energy obtained in the process of reducing the amount of water to 3 is used for rectification rather than being wasted. * Compress 2 to W * 3. It is done like this, and with that, W * 31 From S ZA It is then possible to set the optimum value for energy transfer to W * 31 The part W that is different from * 32 Further compressing W * It can be set to 4. * 32 Further compress and further W * The heat of condensation obtained in the process of reducing the temperature to 4 is introduced into the bottom evaporator in the column. The additional compressor power required is less than the heating steam power saved thereby. The process according to the present invention requires less energy than the prior art process, as shown in Examples 1 and 2. * Compression to 4 results in W * 4 to S UA1 Or S UA To ensure optimal energy transfer to the * 4 pressure and temperature settings can be made.

[0272] 4.8 Step (f) of the method according to the invention In step (f) of the method of the present invention, W * 31Heat transfer medium W of gas different from * Part 3 W * 32 is further compressed, which results in W * 31 Compared to the compressed steam flow W * 4 is obtained.

[0273] After step (f) is performed, W * 4 also W * 32 and W * It is obvious that it is more compressed than 3.

[0274] Steam flow W * The pressure on 4 is "p W*4 " and its temperature is called "T W*4 " is called.

[0275] pressure p W*4 HAp W*3 higher than p W*4 / p W*3 (pressure unit is in each case bar (absolute)) is preferably in the range of 1.1 to 10, more preferably 1.2 to 8, more preferably 1.25 to 7, more preferably 1.3 to 6, more preferably 1.4 to 5, more preferably 1.5 to 2, more preferably 1.5 to 1.8, and most preferably 1.61.

[0276] temperature T W*4 is especially at temperature T W*3 Higher than T W*4 / T W*3 (temperature units are °C in each case) 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, and most preferably 1.08 to 5.

[0277] W in step (f) * 32The compression of the steam W can be carried out according to methods known to those skilled in the art. For example, the compression can be carried out mechanically in a single stage or multiple stages, preferably multiple stages. In the case of multiple stage compression, multiple compressors of the same design or compressors of different designs can be used. The use of single stage or multiple stage compression is dependent on the steam W * 32 depends on the pressure to be compressed. * The compression embodiment described in the context of step (d) of 2 and the preferred compressor type therefor is W * 32 From W * 4, but in particular in step (f), compression in one stage, i.e., compressor VD X Compression using is sufficient.

[0278] 4.9 Step (g) of the method according to the invention In step (g) of the method according to the present invention, W * At least one flow S from at least a portion of 4 UA At least a part of S UA1 After transferring energy to S UA1 RD A Return it to.

[0279] Preferably, in step (g), W * At least one flow S from at least a portion of 4 UA Part of S UA1 After transferring energy to S UA1 RD A Return it to.

[0280] Step (g) determines W * The energy of 4 is reduced, and so, especially W * 4 is at least partially condensed.

[0281] Step (g) of the method according to the invention is preferably carried out according to the following embodiments (g1), (g2), (g3): (g1)W * At least one flow S from at least a portion of 4 UA Part of SUA1 transfers energy to S UA1 RD A Send it back to; (g2)W * At least one flow S from at least a portion of 4 UA Part of S UA1* transfers energy to S UA1* From S UA1 Part of RD A Send it back to; (g3)W * Flow from at least part of 4 UA The energy is transferred to the whole, and then the flow S UA Whole or flow UA Part of S UA1 Only, preferably flow UA Part of S UA1 Only RD A Return it to.

[0282] W * At least one flow S from at least a portion of 4 UA At least a part of S UA1 Transfer of energy to, preferably W * At least one flow S by at least a part of 4 UA At least a part of S UA1 The heating is preferably carried out directly or indirectly.

[0283] "Direct" means that the two flows are not mixed and flow smoothly. * At least a portion of 4 is at least one flow S UA At least a part of S UA1 and thus the energy, in particular the heat, is at least partially transferred to W * 4 to at least one flow UA At least a part of S UA1 This means moving to

[0284] This is W * At least a portion of 4 and at least one flow S UA At least a part of S UA1 and rectification tower RD A Bottom evaporator VSRD Leading through W * 4 has at least one flow S UA At least a part of S UA1 This can be done by heating.

[0285] As a heat transfer device, in particular the heat transfer device WT described below X , W.T. Y , W.T. Z In step (g) of the method according to the invention, in particular, heat exchangers well known to those skilled in the art can be used as the heat exchangers, in particular evaporators. * At least one flow S from at least a portion of 4 UA At least a part of S UA1 The transfer of energy, preferably heat, to the bottom evaporator V SRD It is carried out inside.

[0286] "Indirect" means, in particular, * 4, preferably at least one heat exchanger WT X At least one heat transfer medium W ● 1, in which the heat transfer medium is contacted with at least one stream S UA At least a part of S UA1 Not W, ● 1 is different from that, so that energy, preferably heat, is transferred without mixing of the two streams, W * At least one heat transfer medium W from at least a part of 4 ● 1, and then the heat is ● 1 is flow S UA1 By coming into contact with W ● 1 to at least one flow S UA At least a part of S UA1 In this case, at least one flow S UA At least a part of S UA1 and W ● 1 means either mixed or not mixed, but preferably not mixed.

[0287] In a further embodiment of the method according to the invention, W *At least one flow S from at least a portion of 4 UA At least a part of S UA1 Indirect energy transfer to the * At least one flow S by at least a part of 4 UA At least a part of S UA1 For heating, energy, preferably heat, is first calculated as W * 4 to W ● 1, preferably at least one heat exchanger WT X transmitted by contact via W ● 1 to at least one flow S UA At least a part of S UA1 Further heat transfer medium W ● 2, preferably at least one heat exchanger WT Y Then, in the final step, W ● At least one flow from 2 UA At least a part of S UA1 In this case, heat is transferred to at least one flow S UA At least a part of S UA1 and W ● 2 may or may not be mixed, but preferably not mixed.

[0288] In a further embodiment of the invention, a further heat transfer medium W ● 3. W ● 4. W ● It is obvious that 5 etc. can be used as appropriate.

[0289] Heat medium W ● 1 or other heat transfer medium W to be used ● 2. W ● 3. W ● 4. W ●Any heat transfer medium known to those skilled in the art can be used as 5, and preferably it is selected from the group consisting of air; water; alcohol-water solutions; salt-water solutions (including ionic liquids such as LiBr solutions, dialkylimidazolium salts, especially dialkylimidazolium dialkylphosphates); mineral oils such as diesel oil; thermal oils such as silicone oil; biological oils such as limonene; aromatic hydrocarbons such as dibenzyltoluene. Most preferably, the heat transfer medium W ● 1 is water or air, even more preferably water.

[0290] Salt-water solutions which can be used are described, for example, in DE 102005028451 A1 and WO 2006 / 134015.

[0291] In a preferred embodiment, following step (g), W * From at least some of the 4, especially S UA At least a part of S UA1 After the transfer of energy to the

[0292] In a preferred embodiment of the method according to the invention, the energy, preferably heat, is * 4 is S according to step (g) UA At least a part of S UA1 After transferring energy to W * 4 to S OA or S OA Part of the S supplied to the compression OA Part of S OA1 This is transmitted to S OA It may be a pre-compression of a portion of the

[0293] This allows at least some W * The part of the residual energy or heat still stored by 4 is then taken as S OA Or S OA S is part of OA1It can be used to heat the

[0294] Following step (g), W * At least a portion of the heat transfer medium W obtained after carrying out step (d) or (e) is * 3. W * 31 , W * 32 and recombine with the liquid or gas heat transfer medium W * 1 and can be fed to a new cycle of the process in step (c). * 4 is flow W * 3. W * 31 , W * 32 It is decompressed before merging with one of the

[0295] In a preferred embodiment of the present invention, the heat transfer medium W obtained after step (g) * Part 4 also shows that it is W * It is then reduced to a lower pressure through a valve before being fed into a new cycle as W * Pressure of 4 W * This can be reduced to a preferred range of 1.

[0296] Instead of or in addition to the valve, in step (d) * Before 2 is compressed, energy, in particular heat, is transferred to the heat transfer medium W obtained after step (g). * At least part of 4 to W * 2.

[0297] Alternatively or additionally, the heat transfer medium W obtained after step (g) * A portion of 4 can also be depressurized by a valve or in a condensate container, and then the portion thus depressurized can be transferred to W * 3. Especially gaseous heat transfer medium W * Part 3 W * 31 or W * 32 can be united with one of the

[0298] W * Another preferred additional sink for energy, preferably heat, in at least part of 4 is described below (see paragraph 4.10).

[0299] In a further preferred embodiment, the bottom product stream S AP from, and if step (a2) is carried out, alternatively or additionally from the bottom product stream S BP From S OA or S OA Part of the S supplied to the compression OA Part of S OA1 Energy is transferred to S OA It may be a pre-compression of a portion of the

[0300] In a further preferred embodiment, W * Before 1 is used in step (c), the bottom product stream S AP from, and if step (a2) is carried out, alternatively or additionally from the bottom product stream S BP From W * Energy is transferred to at least a portion of 1.

[0301] 4.10 Preferred Embodiment: Process for Alcohol Exchange Reaction of Alkali Metal Alkoxides In an advantageous embodiment of the invention, the flow W * 3. W * 31 , W * 32 , W *The energy contained in at least one of the four processes is used to operate another industrial process. This is particularly advantageous in integrated site facilities (chemical parks, technology parks) where heating is always required. This energy can be advantageously utilized, especially in integrated systems with multiple alkali metal alkoxide production plants. Such integrated systems typically include a process for alcohol exchange, such as that described in DE-A-2726491. U.S. Pat. No. 3,418,383 and WO 2021 / 122702 describe processes for alcohol exchange from methoxide to propoxide.

[0302] In a preferred embodiment of the present invention, in the method according to the present invention, M c a starting material stream S comprising OR′ and optionally R′OH CE1 a starting material stream S containing R″OH CE2 and reactive rectification column RR C Countercurrent reaction in M C Crude product RP containing OR' and R'OH C Forming M C Bottom product stream S containing OR'' CP RR C The vapor stream S containing R'OH is taken out at the bottom of the CB RR C Remove it at the top of the R' and R'' are two different C1-C6 hydrocarbon groups, and M C is a metal selected from lithium, sodium, and potassium, preferably sodium and potassium, and more preferably sodium; Energy is W * 3. W * 4. A crude product RP C is transmitted to.

[0303] The process according to the invention, according to a preferred embodiment of the invention, is carried out by reacting a given alkali metal alkoxide M c OR' is another alkali metal alkoxide M c OR'' is for alcohol exchange.

[0304] R' and R'' are two different C1 to C6 hydrocarbon groups, preferably two different C1 to C4 hydrocarbon groups.

[0305] Even more preferably, R' is methyl and R'' is a C2-C4 hydrocarbon group.

[0306] Even more preferably, R' is methyl and R'' is selected from ethyl, n-propyl, isopropyl, sec-butyl, 2-methyl-2-butyl, tert-butyl, 2-methyl-2-pentyl, 3-methyl-3-pentyl, 3-ethyl-3-pentyl, 2-methyl-2-hexyl, 3-methyl-3-hexyl, in particular from ethyl, isopropyl, 2-methyl-2-butyl, 3-methyl-3-pentyl, 3-ethyl-3-pentyl.

[0307] Even more preferably, R'=methyl and R''=ethyl.

[0308] The method according to a preferred embodiment of the present invention (hereinafter also referred to as "alcohol exchange reaction") is carried out by a reactive rectification column RR C The RR is suitable as a reactive rectification column. A 4.1 in the context of step (a1) for

[0309] Reactor RR C The can be operated with or without reflux, preferably with reflux. If reflux is provided, in particular steam S CB is partially or completely condensed RRC The condensed vapor is then directed again to the reactor RR Cor, if R' = methyl, the starting material stream S AE1 or S BE1 It can be used as RD when R'=methyl. A It can also be used as a fresh alcohol stream.

[0310] During the alcohol exchange reaction, M C Bottom product stream S containing OR'' CP RR C The vapor stream S containing R'OH is taken out at the bottom of the CB RR C It is taken out at the top of the

[0311] In a preferred embodiment, when R'=methyl, M c a starting material stream S comprising OR′ and optionally R′OH CE1 As, S AP When at least a part of (M A and M B and are different alkali metals, or M A and M B When and are the same alkali metal, especially M A and M B and a different alkali metal) or additionally (especially M A and M B and the same alkali metal), S BP At least a portion of the following is used. Particularly preferably, in this case R"=ethyl. Thus, an alcohol exchange reaction of the alkali metal methoxide to the corresponding alkali metal ethoxide is carried out.

[0312] S BP and S AP If both contain the same alkali metal methoxide, these two streams can be separated or mixed to produce S CE1 and then the starting material stream S CE1 As Tower RR C or two starting material streams S CE1 As Tower RRC can be supplied separately.

[0313] Starting material stream S CE2 In a preferred embodiment, S CE2 The mass fraction of R″OH in S is ≧85 wt. %, even more preferably ≧90 wt. %. CE2 In addition to R''OH, especially M C OR'' or another modifying agent. Starting material S CE2 The alcohols R″OH used as may be commercially available alcohols with a mass proportion of alcohol of more than 99.8% by weight and a mass proportion of water of up to 0.2% by weight.

[0314] "M c a starting material stream S comprising OR′ and optionally R′OH CE1 and a starting material stream S containing R′′OH. CE2 with Countercurrent flow The reaction "constitutes, according to the invention, in particular the reaction of a starting material stream S containing McOR' CE1 At least some of the feed points are C The starting material stream S containing R″OH at CE2 This is ensured by being above the supply point of

[0315] Reactor RR C is operated with or without reflux, preferably with reflux.

[0316] Reactor RR C In a preferred embodiment, the intermediate evaporator V ZC and bottom evaporator V SC The reaction column RR includes at least one evaporator selected from the group consisting of: C is particularly preferably at least one bottom evaporator V SC Includes.

[0317] Reactor RR C In the case of at least one side flow S ZC During the intermediate evaporation, C and is drawn off (“drawn off”) from at least one intermediate evaporator VZC are supplied to.

[0318] Reactor RR C In the case of , there is at least one flow, e.g., S CP However, during bottom evaporation, RR C removed ("extracted") from, at least in part, S CP In this case, preferably, at least one bottom evaporator V SC are supplied to.

[0319] Suitable evaporators that can be used as intermediate and bottom evaporators are described in Section 4.1.

[0320] In the alcohol exchange reaction step, energy, preferably heat, is added to the reaction mixture by the reaction of W * 3. W * 4. A crude product RP C This is preferably achieved by transferring the energy to W * 3. W * 4 from at least a portion of the stream selected from S CE1 or S CE2 , and they are RR C before being fed to the CE1 or S CE2 From the RR where they are mixed C The crude product RP present in C This is done by transmitting the information to

[0321] Therefore, energy, preferably heat, is * 3. W * 4, in particular W * 31 , W * 32 , W * 4, preferably W * 32 , W * 4. A crude product RP from at least one heat transfer medium selected from C is transmitted to.

[0322] "W * 3 from at least a portion of crude product RP C The transfer of energy, preferably heat, to * 31 , W * 32 , W * 3. At least one heat transfer medium selected from W * 31 , W * 32 The crude product RP before separation C It also involves the transfer of energy, preferably heat, to the

[0323] In addition, the crude product RP C is the intermediate evaporator V ZC or bottom evaporator V SC It can also be derived via V ZC Or V SC In this case, energy, preferably heat, is converted into W * 3. W * 4. A crude product RP C can be transmitted to

[0324] In addition, the bottom product stream S CP is partially in the bottom evaporator V SC and then partially again via RR C You can also return it to V SC In this case, energy, preferably heat, is * 3. W * 4 from at least a part of the heat transfer medium selected from S CP The returned part is then transmitted to the tower RR. C Within, S CP The crude product RP present in the column C is transmitted to.

[0325] W * 3. W * The transfer of energy from at least a portion of the heat transfer medium selected from 4 to the aforementioned flow is carried out directly or indirectly, i.e., by the heat transfer medium W, as described correspondingly in section 4.7.△ It is done with or without 1.

[0326] A preferred embodiment of the method according to the invention is * 3. W * From 4, especially W * 4. W * 31 , W * 32 This allows for efficient use of energy from the grid, thereby reducing total energy demand.

[0327] 5. Working Example 5.1 Example 1 (not according to the present invention), corresponding to FIG. An embodiment not according to the present invention is the intercooler WT shown in FIG. 1 (or FIG. 2 or FIG. 3). X <402> 1 except that is not utilized. This also applies to Example 2 not according to the invention and Example 3 according to the invention.

[0328] A flow of 5000 kg / h of aqueous NaOH (50 wt%) AE2 <102> , and the reactor RR was heated at 30°C. A <100> A countercurrent flow of 56,700 kg / h of methanol in the form of vapor, S AE1 <103> Reactor RR A <100> The reaction mixture is fed to the bottom of the reactor RR. A <100> is operated at a top pressure of 1.25 bar (absolute). An almost water-free product stream S of 11000 kg / h is AP* <104> (30 wt. % sodium methoxide in methanol) was added to the column RR A <100> A heating output of about 1200 kW is generated in the reactor RR using low-pressure steam. A <100> Evaporator V SA <105> Methanol-water vapor stream S AB <107> Reactor RR A <100> Of which, 4000 kg / h is taken out at the top of the condenser K RRA <108> and refluxed in the reactor RR A<100> The remaining 50,800 kg / h of the stream is sent to the rectification column RD A <300> Supply to.

[0329] Rectification tower RD A <300> is operated at a top pressure of 1.1 bar (absolute). A liquid water flow of 3500 kg / h, S UA <304> Rectification tower RD A <300> Discharge at the bottom of the RD (500 ppm by weight of methanol). A <300> The bottom temperature of the rectification column RD is 105°C at 1.2 bar (absolute). A <300> At the top of the OA <302> (1.1 bar, 67 ° C; 200 ppm by weight of water) was taken out, of which 43,300 kg / h was used as reflux and condenser K RD <407> In this, most of the condensation heat (9.4 MW) is transferred to the working medium W * 1 <701> n-Butane was evaporated at 61.8 °C and 6.7 bar (absolute) to give a stream W * 2 <702> RD of 56700kg / h A <300> The remaining steam flow is transferred to the compressor VD AB2 <303> where it is compressed to 1.7 bar (absolute) and fed to the reactor RR A <100> Return it to.

[0330] Gaseous n-butane flow W * 2 <702> The compressor VD1 <401> and is preferably heated upstream thereof by a superheater (ΔT=20 K). * 3 <703> Compressor VD X <405> supply to the * 2 <702> Multi-stage compression is performed to * 4 <704> A total of 169t / h of W * 2 <702> Compress and flow W * 4 <704> (18.6 bar (absolute)). This corresponds to a condensation temperature of 110.5°C. Heat transfer device V SRD<406> Set a temperature difference of 5K between the * 4 <704> Steam flow S UA <304> Part of S UA1 <320> and then transmit it again * 1 <701> This is the condenser K RD <407> can be newly supplied to

[0331] flow W * 1 <701> Condenser K RD <407> Before being fed again to * 1 <701> The residual heat of the compressor VD1 <401> The n-butane stream can be superheated upstream of the

[0332] A total of 2.7 MW of electric compressor power is required, while no external heating medium (e.g. steam) is required.

[0333] 5.2 Example 2 (not according to the invention) corresponding to Figure 2: The arrangement of Example 2, not according to the invention, corresponds to the arrangement of Example 1, with the following differences: Rectification tower RD A <300> is the intermediate evaporator V ZRD <409> Rectification tower RD A <300> Liquid flow from S ZA <305> was taken out at 80°C and ZRD <409> Approximately 10,500 kW of heat is transferred in the rectification column RD, where the stream is partially evaporated and then re-entered into the rectification column RD. A <300> are supplied to.

[0334] Rectification tower RD A <300> At the top of the OA <302> (1.1 bar, 67 ° C, 200 ppm by weight of water) was taken out, 43,300 kg / h of which was used as reflux, and condenser K RD <407> In this, most of the condensation heat (9.5 MW) is transferred to the working medium W *1 <701> n-Butane was evaporated at 61.8 °C and 6.7 bar (absolute) to give a stream W * 2 <702> The remaining steam flow of 56700 kg / h is used to AB2 <303> where it is compressed to 1.7 bar (absolute) and fed to the reactor RR A <100> Return it to.

[0335] Gaseous n-butane flow W * 2 <702> The compressor VD1 <401> and is preferably heated upstream by a superheater (ΔT=13 K). * 3 <703> A total of 127t / h of W * 2 <702> Compress and flow W * 3 <703> (11.5 bar (absolute)).

[0336] Compared with Example 1, intermediate evaporator V ZRD <409> Since the temperature of A <300> (It is not 105 °C as in the bottom of the compressor), so there is no need to select a high pressure level for the working fluid n-butane. <401> The power consumption is reduced compared to Example 1. Based on the low temperature rise, the compressor output is 1 MW. ZRD <409> The heat output of the RD is 10.5 MW. However, the use of the heat pump of the described type A <300> It is not possible to achieve complete electrification of the bottom evaporator. <406> It must be operated on low pressure steam (alternatively: another waste heat source) and use 2.04 MW.

[0337] Therefore, a total of 1.0 MW of electricity and 2.04 MW of heating steam is used.

[0338] 5.3 Example 3 (according to the present invention) corresponds to Figure 3: The arrangement of Example 3 according to the invention corresponds to the arrangements of Examples 1 and 2, with the following differences: Rectification tower RD A <300> At the top of the OA<302> (1.1 bar, 67 ° C, 200 ppm by weight of water) was taken out, 43,300 kg / h of which was used as reflux, and condenser K RD <407> Lead via.

[0339] 11.14MW of condensation heat is transferred to condenser K RD <407> The working medium W * 1 <701> n-Butane was evaporated at 61.8 °C and 6.7 bar (absolute) to give a stream W * 2 <702> RD of 56700kg / h A <300> The remaining steam flow is transferred to the compressor VD AB2 <303> where it is compressed to 1.7 bar (absolute) and fed to the reactor RR A <100> Return it to.

[0340] Gaseous n-butane flow W * 2 <702> The compressor VD1 <401> and is preferably heated upstream thereof by a superheater (ΔT=13 K). * 3 <703> (11.5 bar, 110.5°C) is divided.

[0341] Flow rate of 127t / h * 3 <703> (=Ryu W * 31 <7031> ) n-butane at 11.5 bar (absolute) in a side evaporator V ZRD <409> where 10.5 MW is transmitted.

[0342] flow W * 3 <703> The remaining part of W * 32 <7032> , 29t / h, compressor VD X <405> It is supplied to the * 4 <704> Then, the flow W * 4 <704> Bottom evaporator V SRD <406> (2.04MW) and condensed.

[0343] Compressor stage VD1 <401> and VD2 <405> This requires a total of 1.4 MW of power.

[0344] Compared to Examples 1 and 2, the total energy required is reduced under the same boundary conditions and power output. Furthermore, compared to Example 2, no additional heating medium is used. Therefore, the tower is fully electrified. When using green electricity, CO2-free separation can be guaranteed.

[0345] The total energy required is minimized by the method according to Example 3.

[0346] The ratio of the required heating power in each case depending on the low-pressure steam and the compressor power is shown in FIG.

[0347] result: The method according to the invention, in which the heating medium is compressed in stages and the intermediate evaporator and the bottom evaporator are therefore operated with heating medium of different compression, allows for surprising energy savings.

Claims

1. Formula M Ａ OCH ３ wherein M Ａ is selected from sodium, potassium, and lithium; (a1) a starting material stream S containing methanol ＡＥ１ A, M Ａ Starting material stream S containing OH ＡＥ２ and reactive rectification column RR Ａ The reaction is carried out in a countercurrent manner in the Ａ OCH ３ , water, methanol, M Ａ Crude product RP containing OH Ａ Forming Methanol and M Ａ OCH ３ a bottom product stream S comprising ＡＰ RR Ａ and a vapor stream S containing water and methanol is taken out at the lower end of ＡＢ RR Ａ Remove it at the top of the (a2) optionally, simultaneously with and spatially separated from step (a1), a methanol-containing starting material stream S ＢＥ１ A, M Ｂ Starting material stream S containing OH ＢＥ２ and reactive rectification column RR Ｂ The reaction is carried out in a countercurrent manner in the Ｂ OCH ３ , water, methanol, M Ｂ Crude product RP containing OH Ｂ wherein M Ｂ is selected from sodium, potassium, and lithium; Methanol and M Ｂ OCH ３ a bottom product stream S comprising ＢＰ RR Ｂ and a vapor stream S containing water and methanol is taken out at the lower end of ＢＢ RR Ｂ Remove it at the top of the (a3) the vapor flow S ＡＢ and, if step (a2) is performed, S ＡＢ Mixed with or S ＡＢ Separately from the vapor flow S ＢＢ and at least a portion of the above, Ａ Leading to RD Ａ Within, RD Ａ at least one vapor stream S comprising methanol withdrawn at the top end of ＯＡ and RD Ａ At least one stream S comprising water is withdrawn at the lower end of ＵＡ and separated into (b) at least one side stream S ＺＡ RD Ａ Take it out and put it back in the RD Ａ Return it to (c) S ＯＡ A liquid or gas heat transfer medium W ＊ １ The energy is transferred to the gaseous heat transfer medium W ＊ ２ is obtained, (d) Gaseous heat transfer medium W ＊ ２ compressing at least a portion of W ＊ ２ Compared to the compressed gas heat transfer medium W ＊ ３ is obtained, (e) the gaseous heat transfer medium W ＊ ３ The first part W ＊ ３１ From S ＺＡ After transferring energy to S ＺＡ RD Ａ Return it to (f) W ＊ ３１ The gaseous heat transfer medium W ＊ ３ Part W ＊ ３２ is further compressed, thereby ＊ ３１ Compared to the compressed gas heat transfer medium W ＊ ４ is obtained, (g) W ＊ ４ At least a part of S ＵＡ At least a part S of ＵＡ１ After transferring energy to S ＵＡ１ RD Ａ Send it back to method.

2. In step (e), the intermediate evaporator V ＺＲＤ Inside W ＊ ３１ From S ＺＡ The method of claim 1 , further comprising transferring energy to a

3. In step (g), the bottom evaporator V ＳＲＤ Inside W ＊ ４ At least a part of S ＵＡ At least a part S of ＵＡ１ 3. The method of claim 1, wherein the energy is transferred to a

4. According to step (e), ＊ ３１ From S ＺＡ After transferring energy to W ＊ ３１ At least a part of S ＯＡ and / or according to step (g), transferring energy to W ＊ ４ At least a part of S ＵＡ At least a part S of ＵＡ１ After transferring energy to the W ＊ ４ At least a part of S ＯＡ 4. The method according to claim 1, wherein the energy is transferred to a

5. Rectification tower RD Ａ , reaction tower RR Ａ and reaction column RR if step (a2) is carried out. Ｂ 5. The process according to claim 1, wherein at least two columns selected from the group consisting of:

6. S ＯＡ In step (a1), a portion of the starting material stream S ＡＥ１ and if step (a2) is carried out, alternatively or additionally in step (a2) the starting material stream S ＢＥ１ 6. The method according to claim 1, wherein the compound is used as a soluble solid.

7. W ＊ ３ , W ＊ ４ The crude product RP is extracted from at least a portion of the stream selected from Ａ and if step (a2) is carried out, alternatively or additionally, the crude product RP Ｂ 7. The method according to claim 1, wherein the energy is transferred to a

8. M Ａ is selected from sodium, potassium, and when step (a2) is performed, M Ｂ 8. The method according to claim 1, wherein is selected from sodium and potassium.

9. M Ａ is selected from sodium and step (a2) is performed, M Ｂ 9. The method of claim 8, wherein is selected from potassium.

10. M ｃ a starting material stream S containing OR′ ＣＥ１ into a starting material stream S containing R″OH ＣＥ２ and reactive rectification column RR Ｃ The reaction is carried out in a countercurrent manner in the Ｃ Crude product RP containing OR″ and R′OH Ｃ Forming M Ｃ bottom product stream S containing OR″ ＣＰ RR Ｃ and a vapor stream S containing R'OH is taken out at the lower end of ＣＢ RR Ｃ Remove it at the top of the R' and R'' are two different C １ ~C ６ is a hydrocarbon group, M Ｃ is a metal selected from lithium, sodium, and potassium; W ＊ ３ , W ＊ ４ The crude product RP is extracted from at least a portion of the stream selected from Ｃ 10. The method according to claim 1, wherein the energy is transferred to a

11. 11. The method of claim 10, wherein R'=methyl.

12. S ＡＰ is obtained according to the method of any one of claims 1 to 9, ＡＰ At least a part of ＣＥ１ The method according to claim 11, wherein the compound is used as

13. S ＢＰ is obtained according to the process of any one of claims 1 to 9 under step (a2), ＢＰ At least a part of ＣＥ１ The method according to claim 11, wherein the compound is used as

14. 14. The process of any one of claims 11 to 13, wherein R'' is selected from ethyl, n-propyl, isopropyl, sec-butyl, 2-methyl-2-butyl, tert-butyl, 2-methyl-2-pentyl, 3-methyl-3-pentyl, 3-ethyl-3-pentyl, 2-methyl-2-hexyl, 3-methyl-3-hexyl.

15. 15. The method of claim 14, wherein R''=ethyl.

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