Method for the continuous separation of mixtures comprising morpholine (mo), monoaminodiglycol (adg), ammonia and water by means of distillation

Abstract

Processes for the continuous fractional distillation of a mixture comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water from a reaction of diethylene glycol (DEG) with ammonia, the process comprising: (i) separating off ammonia from the mixture at a top of a first distillation column K 10 ; (ii) feeding a bottom fraction from K 10 to a second distillation column K 20 in which water and organic products are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.1 to 15 bar, (iii) feeding a bottom fraction from K 20 to a third distillation column K 30 , wherein the column K 30 is a dividing wall column (DWC) which preferably has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region ( 1 ), a lower combined column region ( 6 ), an inflow part ( 2, 4 ) having an enrichment section ( 2 ) and a stripping section ( 4 ), and also an offtake part ( 3, 5 ) having an enrichment section ( 3 ) and a stripping section ( 5 ), with the bottoms from K 20 being fed in in the upper or middle third of the inflow part ( 2, 4 ), based on the number of theoretical plates of the inflow part, ADG and organic products having a boiling point of >190° C. (1.013 bar) being discharged at the bottom, organic products having a boiling point of ≦128° C. (1.013 bar) being discharged at the top and MO being discharged from the middle or lower third of the offtake part ( 3, 5 ) (side offtake), based on the number of theoretical plates of the offtake part.

Claims

1 - 41 . (canceled) 42 . A process for the continuous fractional distillation of a mixture comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water from a reaction of diethylene glycol (DEG) with ammonia, the process comprising: separating off ammonia from the mixture at a top of a first distillation column K 10 ; feeding a bottom fraction from K 10 to a second distillation column K 20 in which water and organic products are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.1 to 15 bar, feeding a bottom fraction from K 20 to a third distillation column K 30 , wherein the column K 30 is a dividing wall column (DWC) which preferably has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region ( 1 ), a lower combined column region ( 6 ), an inflow part ( 2 , 4 ) having an enrichment section ( 2 ) and a stripping section ( 4 ), and also an offtake part ( 3 , 5 ) having an enrichment section ( 3 ) and a stripping section ( 5 ), with the bottoms from K 20 being fed in in the upper or middle third of the inflow part ( 2 , 4 ), based on the number of theoretical plates of the inflow part, ADG and organic products having a boiling point of >190° C. (1.013 bar) being discharged at the bottom, organic products having a boiling point of ≦128° C. (1.013 bar) being discharged at the top and MO being discharged from the middle or lower third of the offtake part ( 3 , 5 ) (side offtake), based on the number of theoretical plates of the offtake part. 43 . The process according to claim 42 , wherein at least a portion of the organic products separated off at the top of column K 30 are recirculated to the feed to the column K 20 . 44 . The process according to claim 42 , wherein the column K 10 has from 3 to 30 theoretical plates and is operated at a pressure of 5 to 30 bar. 45 . The process according to claim 42 , wherein the column K 20 has from 25 to 70 theoretical plates and is operated at a pressure of 0.1 to 10 bar. 46 . The process according to claim 42 , wherein the dividing wall column K 30 has from 30 to 100 theoretical plates and is operated at a pressure of 0.01 to 5 bar. 47 . The process according to claim 42 , wherein the feed point of column K 10 is located in the upper third, based on the number of theoretical plates. 48 . The process according to claim 42 , wherein the feed point of column K 20 is located in the middle third, based on the number of theoretical plates. 49 . The process according to claim 42 , wherein the subregion of the column (DWC) divided by the dividing wall (DW) and comprising the subregions 2 , 3 , 4 and 5 or parts thereof is provided with ordered packing, random packing elements and/or trays and the dividing wall in these subregions is thermally insulating. 50 . The process according to claim 42 , wherein the stream comprising water and organic products which is separated off at the top of the column K 20 is fed to a column K 50 in which aqueous N-ethylmorpholine solution (aqueous E-MO solution) is separated off at the top or at a side offtake for liquid and water is separated off at the bottom. 51 . The process according to claim 50 , wherein the column K 50 has from 10 to 50 theoretical plates and is operated at a pressure of 0.1 to 16 bar. 52 . The process according to claim 50 , wherein the feed point of column K 50 is located in the upper or middle third, based on the number of theoretical plates. 53 . The process according to claim 50 , wherein the aqueous N-ethylmorpholine solution is dewatered and the organic phase formed here is then concentrated by distillation to give the desired product. 54 . The process according to claim 50 , wherein the bottoms from K 30 are fed to a distillation column K 60 in which ADG is separated off at a side offtake, organic products having a boiling point of ≦224.8° C. (1.013 bar) are separated off at the top and organic products having a boiling point of >255° C. (1.013 bar) are separated off at the bottom. 55 . The process according to claim 54 , wherein the column K 60 has from 20 to 80 theoretical plates and is operated at a pressure of 0.005 to 1 bar. 56 . The process according to claim 54 , wherein the feed point of column K 60 is located in the middle or lower third, based on the number of theoretical plates, and the ADG side offtake located opposite the feed point is located from 1 to 30 theoretical plates above the feed point. 57 . The process according to claim 54 , wherein organic products separated off at the top of the column K 60 are discharged or recirculated to the reaction of DEG with ammonia. 58 . The process according to claim 54 , wherein the ADG-comprising stream separated off at the side offtake of the column K 60 is fed to a column K 70 in which ADG is separated off at a side offtake, organic products having a boiling point of ≧224.8° C. (1.013 bar) are separated off at the bottom and organic products having a boiling point of ≦224.8° C. (1.013 bar) are separated off at the top. 59 . The process according to claim 58 , wherein the column K 70 has from 10 to 80 theoretical plates and is operated at a pressure of 0.005 to 1 bar. 60 . The process according to claim 58 , wherein the feed point of column K 70 is located in the upper or middle third, based on the number of theoretical plates, and the ADG side offtake located opposite the feed point is located from 1 to 30 theoretical plates above the feed point. 61 . The process according to claim 58 , wherein products separated off at the bottom of column K 70 are recirculated to the reaction of DEG with ammonia. 62 . The process according to claim 58 , wherein products separated off at the top of column K 70 are recirculated to the reaction of DEG with ammonia. 63 . The process according to claim 54 , wherein the column K 60 is a dividing wall column (DWC 2 ). 64 . The process according to claim 63 , wherein the dividing wall column (DWC 2 ) has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region ( 1 ), a lower combined column region ( 6 ), an inflow part ( 2 , 4 ) having an enrichment section ( 2 ) and a stripping section ( 4 ), and also an offtake part ( 3 , 5 ) having an enrichment section ( 3 ) and a stripping section ( 5 ), with the bottoms from K 30 being fed in in the upper or middle third of the inflow part ( 2 , 4 ), based on the number of theoretical plates of the inflow part, organic products having a boiling point of >255° C. (1.013 bar) being discharged at the bottom, organic products having a boiling point of ≦224.8° C. (1.013 bar) being discharged at the top, ADG being discharged from the column region 1 and optionally gaseous organic products having a boiling point of ≧224.8° C. (1.013 bar) being discharged from the upper or middle third of the offtake part ( 3 , 5 ) (side offtake), based on the number of theoretical plates of the offtake part. 65 . The process according to claim 64 , wherein products separated off in gaseous form at the side offtake are recirculated to the reaction of DEG with ammonia. 66 . The process according to claim 63 , wherein the dividing wall column (DWC 2 ) has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region ( 1 ) and ( 2 ), an inflow part ( 3 , 4 ) having an enrichment section ( 3 ) and a stripping section ( 4 ), and also a part ( 5 ), with the dividing wall DW extending to the bottom of the column and the bottoms from K 30 being fed in in the upper or middle third of the inflow part ( 3 , 4 ), based on the number of theoretical plates of the inflow part, DEG and organic products having a boiling point of ≧224.8° C. (1.013 bar) being discharged at the bottom below the part 5 , organic products having a boiling point of >255° C. (1.013 bar) being discharged at the bottom below the parts 3 and 4 , organic products having a boiling point of ≦224.8° C. (1.013 bar) being discharged at the top and ADG being discharged from the middle part of the upper combined column region ( 1 ) and ( 2 ) (side offtake). 67 . The process according to claim 66 , wherein products separated off at the bottom below the part 5 are recirculated to the reaction of DEG with ammonia. 68 . The process according to claim 63 , wherein the dividing wall column K 60 has from 30 to 100 theoretical plates and is operated at a pressure of 0.005 to 1 bar. 69 . The process according to claim 63 , wherein the dividing wall is thermally insulating. 70 . The process according to claim 63 , wherein organic products separated off at the top are recirculated to the reaction of DEG with ammonia. 71 . The process according to claim 54 , wherein at least a portion of the ADG-comprising stream separated off at the top of the column K 60 is fed to a column K 80 in which ADG and organic products having a boiling point of ≧224.8° C. (1.013 bar) are separated off at the bottom and organic products having a boiling point of ≦224.8° C. (1.013 bar) are separated off at the top. 72 . The process according to claim 71 , wherein ADG is additionally separated off at a side offtake of the column K 80 . 73 . The process according to claim 71 , wherein products separated off at the bottom of column K 80 are recirculated to the feed to the column K 60 . 74 . The process according to claim 71 , wherein products separated off at the top of column K 80 are discharged or recirculated to the reaction of DEG with ammonia. 75 . The process according to claim 71 , wherein the column K 80 has from 10 to 80 theoretical plates and is operated at a pressure of 0.005 to 3 bar. 76 . The process according to claim 71 , wherein the feed point of column K 80 is located in the upper or middle third, based on the number of theoretical plates, and the ADG side offtake located opposite the feed point is located 1 to 30 theoretical plates below the feed point. 77 . The process according to claim 42 , wherein the mixture comprises morpholine, monoaminodiglycol, ammonia, water, N-ethylmorpholine, 1,2-ethylenediamine and an organic product having a boiling point of >224.8° C. (1.013 bar). 78 . The process according to claim 42 , wherein the mixture is produced by reaction of diethylene glycol with ammonia in the presence of a heterogeneous catalyst selected from catalysts comprising Cu, Ni and Co on a zirconium dioxide support and catalysts comprising Cu and Ni on an aluminum oxide support. 79 . The process according to claim 42 , wherein a morpholine product is obtained having a purity of ≧99.5% by weight, an N-ethylmorpholine content of ≦0.20% by weight, a 1,2-ethylenediamine content of ≦0.30% by weight, a 2-methoxyethanol content of <0.50% by weight and a water content of ≦0.05% by weight. 80 . The process according to claim 42 , wherein a morpholine product is obtained having an APHA color number of ≦10 and a chloride content of ≦15 mg/liter. 81 . The process according to claim 42 , wherein a morpholine product is obtained having a purity of ≧98.00% by weight, a DEG content of ≦0.40% by weight, a water content of ≦0.20% by weight and an APHA color number of ≦20. 82 . The process according to claim 42 , wherein a morpholine product is obtained having a purity of ≧98.50% by weight, a water content of ≦0.30% by weight and an APHA color number of ≦50.
[0001] The present invention relates to a process for the continuous fractional distillation of mixtures comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water obtained by reaction of diethylene glycol (DEG) of the formula [0000] [0000] with ammonia. [0002] Aminodiglycol (ADG) [=2-(2-aminoethoxy)ethanol=2,2′-aminoethoxyethanol, formula [0000] [0000] and morpholine are used, inter alia, as solvents, stabilizers, for the synthesis of chelating agents, synthetic resins, drugs, inhibitors and surface-active substances. N-Ethylmorpholine (E-MO) is used, inter alia, as catalyst for the production of polyurethane foams. [0003] Numerous methods of preparing ADG and morpholine are described in the literature. [0004] Ullmann's Encyclopedia of Industrial Chemistry, 6th Edition, 2000 electronic release, Wiley-VCH Verlag, Rubrik ‘cyclic amines’ in the chapter ‘aliphatic amines’, describes the synthesis of ADG and MO by amination of DEG under hydrogen pressure and in the presence of a cobalt or nickel catalyst (citations: EP-A-696 572 (BASF AG), DE-A-1 049 864) or other catalysts (citations: DE-A-3 002 342, DE-A-3 125 662 (BASF AG), U.S. Pat. No. 3,155,657). [0005] The earlier German patent application No. 102005047458.6 of Sep. 30, 2005 and the earlier European (subsequent) patent application No. 06101339.7 of Feb. 6, 2006 (BASF AG) relate to a process for preparing ADG and morpholine by reaction of DEG with ammonia in the presence of a specific copper, nickel and cobalt heterogeneous catalyst and also in general terms the work-up by multistage distillation. [0006] Two parallel European patent applications having the same filing date (both BASF AG) relate to processes for the continuous fractional distillation of mixtures comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water obtained by reaction of diethylene glycol (DEG) with ammonia. [0007] A parallel European patent application having the same filing date (BASF AG) relates to a process for preparing electronics-grade ADG. [0008] The synthesis of morpholine and monoaminodiglycol is notable for the formation of many secondary components. Unreacted starting materials, products of value and the by-products are separated off by distillation, which leads to a considerable outlay in terms of apparatus and energy. [0009] It was an object of the present invention to overcome a disadvantage or a number of disadvantages of the prior art and discover an improved economical process for the fractionation of mixtures comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water and possibly N-ethylmorpholine (E-MO) and possibly 1,2-ethylenediamine (EDA) and possibly organic products having a boiling point of >224.8° C. (1.013 bar). The individual organic components (amines), in particular MO and ADG and possibly E-MO, should be obtained in high purity and quality (e.g. color quality). [0010] We have accordingly found a process for the continuous fractional distillation of mixtures comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water obtained by reaction of diethylene glycol (DEG) with ammonia, which comprises separating off ammonia at the top of a first distillation column K 10 , [0000] feeding the bottoms from MO to a second distillation column K 20 in which water and organic products are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.1 to 15 bar, feeding the bottoms from K 20 to a third distillation column K 30 in which MO and organic products having a boiling point of <140° C. (1.013 bar) are separated off at the top or at a side offtake and ADG and organic products having a boiling point of >190° C. (1.013 bar) are separated off at the bottom, and feeding the MO-comprising stream which is separated off at the top or at a side offtake of the column K 30 to a column K 40 in which MO is separated off at a side offtake, organic products having a boiling point of ≦128° C. (1.013 bar), preferably <128° C. (1.013 bar), are separated off at the top and organic products having a boiling point of ≧128° C. (1.013 bar) are separated off at the bottom. [0011] The organic products separated off at the bottom of column K 40 are preferably recirculated in their entirety or in part, particularly preferably in their entirety, to the feed to the column K 30 . [0012] The bottoms from the column K 40 comprise, in a preferred mode of operation, >94% by weight, particularly preferably >96% by weight, very particularly preferably from 98 to 99% by weight, of morpholine which is recirculated to the inlet of the column K 30 . In this way, any entrained high boilers can be discharged via the bottom of the column K 30 . [0013] If the products separated off at the bottom of column K 40 are not recirculated or only partly recirculated to the feed to the column K 30 , they can be marketed for some applications, even as MO product. [0014] The column K 10 preferably has from 3 to 30, particularly preferably from 5 to 20, theoretical plates. [0015] It is preferably operated at a pressure in the range from 5 to 30 bar, particularly preferably from 10 to 20 bar. [0016] The feed point of column K 10 is preferably located in the upper third, based on the number of theoretical plates. [0017] The column K 20 preferably has from 25 to 70, particularly preferably from 30 to 60, theoretical plates. [0018] It is preferably operated at a pressure in the range from 0.1 to 10 bar, particularly preferably from 0.8 to 7 bar. [0019] The feed point of column K 20 is preferably located in the middle third, based on the number of theoretical plates. [0020] Water is preferably separated off in the column K 20 . Organic products, some of which have boiling points higher than that of the bottom product morpholine, are preferably separated off at the top together with this water as a minimum-boiling azeotrope. [0021] The column K 30 preferably has from 5 to 25, particularly preferably from 7 to 20, theoretical plates. [0022] It is preferably operated at a pressure in the range from 0.01 to 5 bar, particularly preferably from 0.1 to 2.5 bar. [0023] The feed point of column K 30 is preferably located in the upper third, based on the number of theoretical plates. [0024] In an alternative embodiment, the side offtake is preferably located from 1 to 8 theoretical plates, particularly preferably from 2 to 6 theoretical plates, above the feed point. [0025] The column K 40 preferably has from 10 to 80, particularly preferably from 15 to 60, theoretical plates. [0026] It is preferably operated at a pressure in the range from 0.01 to 12 bar, particularly preferably from 0.5 to 6 bar. [0027] The feed point of column K 40 is preferably located in the upper or middle third, particularly preferably the middle third, based on the number of theoretical plates. [0028] The MO side offtake located opposite the feed point is preferably located from 1 to 30 theoretical plates, particularly preferably from 2 to 25 theoretical plates, below the feed point. [0029] In the column K 40 , organic products having a boiling point of ≦128° C. (1.013 bar), preferably <128° C. (1.013 bar), e.g. EDA, are separated off at the top and organic products having a boiling point of ≧128° C. (1.013 bar) are separated off at the bottom. [0030] The organic products separated off at the top of the column K 40 , in particular EDA, can advantageously be recirculated in their entirety or in part to the feed to the column K 20 . [0031] In a further embodiment, pure EDA can be obtained as product of value by further purification by distillation of the overhead distillate. [0032] In a particular embodiment, the stream comprising water and organic products which is separated off at the top of the column K 20 is fed to a column K 50 in which aqueous N-ethylmorpholine solution (aqueous E-MO solution) is separated off at the top or at a side offtake for liquid, with the side offtake for liquid preferably being located in the up-' per third of the column, based on the number of theoretical plates, and water is separated off at the bottom. [0033] The column K 50 preferably has from 10 to 50, particularly preferably from 15 to 40, theoretical plates. [0034] It is preferably operated at a pressure in the range from 0.1 to 16 bar, particularly preferably from 0.2 to 8 bar. [0035] The feed point of column K 50 is preferably located in the upper or middle third, particularly preferably in the middle third, based on the number of theoretical plates. [0036] To isolate pure E-MO, the aqueous N-ethylmorpholine solution is firstly dewatered. As dewatering agent, preference is given to using sodium hydroxide, e.g. as a 40-60% strength by weight aqueous solution, particularly preferably a 50% strength by weight aqueous solution. The dewatering using the sodium hydroxide is preferably carried out continuously in an extraction column. The extraction temperature is preferably 25-60° C., particularly preferably 30-55° C. The sodium hydroxide solution is diluted to 15-35% by weight, particularly preferably 20-30% by weight, during the extraction. [0037] After phase separation, the organic phase is worked up in a continuous or batch distillation. The distillation is preferably carried out batchwise in a still pot. [0038] In this case, the overhead products are obtained in succession: ethylamine if present, possibly ethanol as aqueous azeotrope, possibly N-methylmorpholine as aqueous azeotrope, possibly water-free N-methylmorpholine and the desired product N-ethylmorpholine (E-MO). [0039] In a preferred embodiment, the bottoms from K 30 are fed to a distillation column K 60 in which ADG is separated off at a side offtake, organic products having a boiling point of ≦224.8° C. (1.013 bar) are separated off at the top and organic products having a' boiling point of >255° C. (1.013 bar) are separated off at the bottom. [0040] The column K 60 preferably has from 20 to 80, particularly preferably from 30 to 70, theoretical plates. [0041] It is preferably operated at a pressure in the range from 0.005 to 1 bar, particularly preferably from 0.01 to 0.7 bar. [0042] The feed point of column K 60 is preferably located in the middle or lower third, particularly preferably the middle third, based on the number of theoretical plates. [0043] The ADG side offtake located opposite the feed point is preferably located from 1 to 30, particularly preferably from 2 to 20, theoretical plates above the feed point. [0044] In a preferred embodiment, organic products separated off at the top of the column K 60 , e.g. N-(2-aminoethyl)morpholine, 2-(2-aminoethoxy)ethylamine, are recirculated to the reaction of DEG with ammonia. [0045] To avoid accumulation of individual components in the circuit of the production plant, a substream of the distillate separated off at the top of the column is preferably discharged. The proportion of the recirculated stream is preferably 40-100% by weight, particularly preferably 50-100% by weight, of the distillate separated off at the top of the column. [0046] The organic products separated off at the bottom of the column K 60 can advantageously be used as milling aids in the cement industry. [0047] The ADG-comprising stream separated off at the side offtake of the column K 60 is preferably fed to a column K 70 in which ADG is separated off at a side offtake, organic products having a boiling point of ≧224.8° C. (1.013 bar), particularly preferably >235° C. (1.013 bar), are separated off at the bottom and organic products having a boiling point of ≦224.8° C. (1.013 bar) are separated off at the top. [0048] The column K 70 preferably has from 10 to 80, particularly preferably from 20 to 70, theoretical plates. [0049] It is preferably operated at a pressure in the range from 0.005 to 1 bar, particularly preferably from 0.01 to 0.7 bar. [0050] The feed point of column K 70 is preferably located in the upper or middle third, preferably the middle third, based on the number of theoretical plates. The ADG side offtake located opposite the feed point is preferably located from 1 to 30, particularly preferably from 2 to 25, theoretical plates above the feed point. [0051] Products separated off at the bottom of column K 70 , e.g. DEG, morpholylaminodiglycol, morpholinodiglycol, are preferably recirculated to the reaction of DEG with ammonia. [0052] (Morpholylaminodiglycol=4-(2-(2-aminoethoxy)ethyl)morpholine, C 8 H 18 N 2 O 2 ; morpholinodiglycol (morpholinylethoxyethanol) CAS No. 3603-45-0, C 8 H 17 NO 3 ) [0053] Products separated off at the top of column K 70 , e.g. ADG, N-(2-aminoethyl)morpholine, 2-(2-aminoethoxy)ethylamine, are preferably recirculated to the reaction of DEG with ammonia. [0054] The proportion of the recirculated stream is preferably 80-100% by weight, particularly preferably 95-100% by weight, of the distillate separated off at the top of the column. [0055] In a further particularly preferred embodiment, the column K 60 is a dividing wall column (DWC). [0056] The dividing wall column (DWC) preferably has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region ( 1 ), a lower combined column region ( 6 ), an inflow part ( 2 , 4 ) having an enrichment section ( 2 ) and a stripping section ( 4 ), and also an offtake part ( 3 , 5 ) having an enrichment section ( 3 ) and a stripping section ( 5 ), with the bottoms from K 30 being fed in in the upper or middle third, particularly preferably the upper third, of the inflow part ( 2 , 4 ), based on the number of theoretical plates of the inflow part, organic products having a boiling point of >255° C. (1.013 bar) being discharged at the bottom, organic products having a boiling point of ≦224.8° C. (1.013 bar) being discharged at the top, ADG being discharged from the column region 1 and optionally, in a particular embodiment preferably, gaseous organic products having a boiling point of ≧224.8° C. (1.013 bar), particularly preferably >235° C. (1.013 bar), e.g. DEG, being discharged from the upper or middle third, particularly preferably the upper third, of the offtake part ( 3 , 5 ) (side offtake), based on the number of theoretical plates of the offtake part. [0057] Organic products separated off in gaseous form at the side offtake of the column K 60 , e.g. DEG, are preferably recirculated to the reaction of DEG with ammonia. [0058] In a further advantageous embodiment, the dividing wall column (DWC) has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region ( 1 ) and ( 2 ), an inflow part ( 3 , 4 ) having an enrichment section ( 3 ) and a stripping section ( 4 ), and also a part ( 5 ), with the dividing wall DW extending to the bottom of the column and the bottoms from K 30 being fed in in the upper or middle third, particularly preferably the upper third, of the inflow part ( 3 , 4 ), based on the number of theoretical plates of the inflow part, DEG and organic products having a boiling point of ≧224.8° C. (1.013 bar), preferably >235° C. (1.013 bar), being discharged at the bottom below the part 5 , organic products having a boiling point of >255° C. (1.013 bar) (high boilers=HB) being discharged at the bottom below the parts 3 and 4 , organic products having a boiling point of ≦224.8° C. (1.013 bar) being discharged at the top and ADG being discharged from the middle part of the upper combined column region ( 1 ) and ( 2 ) (side offtake). [0059] The dividing wall column K 60 preferably has from 30 to 100, particularly preferably from 40 to 90, theoretical plates. [0060] It is preferably operated at a pressure in the range from 0.005 to 1 bar, particularly preferably from 0.01 to 0.7 bar. [0061] The subregion of the column (DWC) divided by the dividing wall (DW) and comprising the subregions 3 , 4 and 5 or 2 , 3 , 4 and 5 or in each case parts thereof is preferably provided with ordered packing, random packing elements and/or trays. The dividing wall in these subregions is preferably thermally insulating. [0062] In a preferred embodiment, organic products separated off at the top of the column K 60 , e.g. N-(2-aminoethyl)morpholine, 2-(2-aminoethoxy)ethylamine, are not discharged from the process but are recirculated to the reaction of DEG with ammonia. [0063] Organic products separated off at the bottom below the part 5 of column K 60 having a dividing wall DW extending to the bottom of the column, e.g. DEG, are preferably recirculated to the reaction of DEG with ammonia. [0064] The proportion of the recirculated stream is preferably 80-100% by weight, particularly preferably 95-100% by weight, of the distillate separated off at the top of the column. [0065] In particular embodiments using a dividing wall column (DWC), the process of the invention advantageously displays a lower heat requirement compared to the 2- or 3-column arrangement (K 60 -K 70 or K 80 ) and a reduced number of columns. [0066] In a particular embodiment of the process of the invention, the ADG-comprising stream/streams separated off at the top of the columns K 60 and/or K 70 is/are fed in its/their entirety or in part to a column K 80 in which ADG and organic products having a boiling point of ≧224.8° C. (1.013 bar) are separated off at the bottom and organic products having a boiling point of ≦224.8° C. (1.013 bar) are separated off at the top. [0067] The ADG obtained at the bottom can be utilized as product of value. [0068] ADG in particularly pure form is preferably additionally separated off at a side offtake of the column K 80 . [0069] In this case, products separated off at the bottom of column K 80 are preferably recirculated to the feed to the columns K 60 and/or K 70 . [0070] Products separated off at the top of column K 80 are preferably recirculated to the reaction of DEG with ammonia. [0071] To avoid accumulation of individual components in the circuit of the production plant, a substream of the distillate separated off at the top of the column is preferably discharged. The proportion of the recirculated stream is preferably 0-100% by weight, particularly preferably 0-50% by weight, of the distillate separated off at the top of the column. [0072] The column K 80 preferably has from 10 to 80, particularly preferably from 15 to 60, theoretical plates. [0073] It is preferably operated at a pressure in the range from 0.005 to 3 bar, particularly preferably from 0.01 to 2 bar. [0074] The feed point of column K 80 is preferably located in the upper or middle third, preferably the upper third, based on the number of theoretical plates. [0075] The ADG side offtake located opposite the feed point is preferably located from 1 to 30, particularly preferably from 2 to 25, theoretical plates below the feed point. [0076] In particular embodiments, the process of the invention is additionally advantageous as a result of the following heat integration measures: [0000] The heat from the vapor from K 80 can be integrated into K 50 . The heat from the vapor from K 70 can be integrated into K 50 and/or K 80 , preferably K 50 . The heat from the vapor from K 60 can be integrated into K 50 . The heat from the vapor from K 40 can be integrated into K 20 , K 50 and/or K 80 . The heat from the vapor from the dividing wall column K 60 can be integrated into K 50 . [0077] This heat integration can be effected as follows: [0078] To be able to make maximum use of the heat obtained from the vapor, a heat transfer medium is preferably dispensed with and the vapor streams are preferably condensed directly in the corresponding vaporizers instead of heating steam. As vaporizers, it is in each case possible to use natural convection vaporizers, forced circulation vaporizers, forced circulation depressurization vaporizers, falling film evaporators, Robert evaporators, kettle-type vaporizers; thin film evaporators or climbing film evaporators. Preference is in each case given to using natural convection vaporizers, forced circulation vaporizers, forced circulation depressurization vaporizers, falling film evaporators, Robert evaporators or kettle-type vaporizers. [0079] The residual vapors are preferably in each case liquefied in an after-condenser. [0080] Furthermore, it is advantageous for the heat of reaction from the synthesis of the mixture to be fractionated to be removed, in particular by evaporative cooling (steam), and integrated into the distillation. Embodiments (A) and (B) are particularly preferred in the synthesis. [0081] The heat of reaction can here be integrated into the columns K 20 , K 50 , K 30 , K 40 , K 70 and/or K 80 , preferably into the columns K 20 , K 40 and/or K 80 . [0082] The mixture comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water, and possibly E-MO and possibly EDA and possibly organic products having a boiling point of >224.8° C. (1.013 bar) which is used in the process of the invention has, in an embodiment (A), preferably been obtained by reaction of diethylene glycol (DEG) with ammonia in the presence of a catalyst comprising Cu, Ni and Co on zirconium dioxide as support. [0083] Catalysts of this type are described in EP-A-963 975, EP-A-1 106 600 and WO-A-03/076386 (all BASF AG). [0084] In a particularly preferred catalyst, the catalytically active composition of the catalyst before treatment with hydrogen comprises from 20 to 65% by weight of zirconium dioxide (ZrO 2 ), from 1 to 30% by weight of oxygen-comprising compounds of copper, calculated as CuO, from 15 to 50% by weight of oxygen-comprising compounds of nickel, calculated as NiO, and from 15 to 50% by weight of oxygen-comprising compounds of cobalt, calculated as CoO. [0085] The temperature in the reactor which is preferred for the reaction of diethylene glycol (DEG) with ammonia is in the range from 170 to 220° C. Preference is given to isothermal operation of the reactor. The pressure preferred for the reaction of diethylene glycol (DEG) with ammonia is in the range from 100 to 200 bar. [0086] The reaction of diethylene glycol (DEG) with ammonia is preferably carried out in the presence of hydrogen. The hydrogen is preferably recirculated as recycle gas via a high-pressure separator to the reactor. [0087] The molar ratio of ammonia:DEG is preferably in the range from 4 to 6. [0088] The DEG conversion is preferably in the range from 55 to 90%. [0089] The mixture used in the process of the invention is particularly preferably produced as described in the earlier German patent application No. 102005047458.6 of Sep. 30, 2005 and the earlier European (subsequent) patent application No. 06101339.7 of Feb. 6, 2006 (BASF AG), according to which the reaction of DEG with ammonia is carried out in the presence of a specific shaped catalyst body and the catalytically active composition of the catalyst before treatment with hydrogen comprises oxygen-comprising compounds of aluminum and/or zirconium, copper, nickel and cobalt. [0090] In another embodiment (B), the mixture comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water, and possibly E-MO and possibly EDA and possibly organic products having a boiling point of >224.8° C. (1.013 bar), which is used in the process of the invention has preferably been obtained by reaction of diethylene glycol (DEG) with ammonia in the presence of a catalyst comprising Cu and Ni on aluminum oxide as support, as described, in particular, in EP-A-70 397 (BASF AG). Catalysts of this type are also described in EP-A-514 692 and EP-A-167 872 (both BASF AG). [0091] In a catalyst which is particularly preferred here, the catalytically active composition of the catalyst before treatment with hydrogen comprises from 25 to 65% by weight of aluminum oxide (Al 2 O 3 ), from 30 to 60% by weight of oxygen-comprising compounds of copper, calculated as CuO, and from 5 to 15% by weight of oxygen-comprising compounds of nickel, calculated as NiO. [0092] The temperature in the reactor which is preferred for the reaction of diethylene glycol (DEG) with ammonia is in this case in the range 190-235° C. Preference is given to isothermal operation of the reactor. The pressure preferred for the reaction of diethylene glycol (DEG) with ammonia is in the range from 20 to 30 bar. [0093] The reaction of diethylene glycol (DEG) with ammonia is preferably carried out in the gas phase in the presence of hydrogen. The gaseous output from the reactor is preferably fed to a heat exchanger in which a partial condensation is preferably carried out (condensation of crude morpholine). The gas phase comprising H 2 and NH 3 is preferably conveyed back to the DEG vaporizer and then into the reactor. [0094] The process of the invention is particularly advantageous for preparing morpholine (MO) [0000] having a purity of ≧99.5% by weight, particularly preferably ≧99.6% by weight, e.g. from 99.65 to 99.95% by weight, an N-ethylmorpholine (E-MO) content of ≦0.20% by weight, particularly preferably ≦0.10% by weight, e.g. from 0.01 to 0.08% by weight, a 1,2-ethylenediamine (EDA) content of ≦0.30% by weight, particularly preferably ≦0.20% by weight, e.g. from 0.05 to 0.15% by weight, a 2-methoxyethanol content of <0.50% by weight, particularly preferably <0.30% by weight, e.g. from 0.05 to 0.25% by weight, and a water content of ≦0.05% by weight, particularly preferably ≦0.04% by weight, e.g. from 0.01 to 0.03% by weight. [0095] It is very particularly preferably advantageous for preparing morpholine (MO) having an APHA color number of ≦10, particularly preferably ≦8, e.g. from 2 to 7, [0000] and a chloride content of ≦15 mg/liter, particularly preferably ≦5 mg/liter, very particularly preferably ≦1 mg/liter, e.g. from 0.1 to 0.9 mg/liter. [0096] The process of the invention is also particularly advantageous for preparing monoaminodiglycol (ADG) having a purity of ≧98.00% by weight, particularly preferably, ≧98.30% by weight, e.g. from 98.50 to 99.50% by weight, [0000] a DEG content of ≦0.40% by weight, particularly preferably ≦0.10% by weight, e.g. from 0.01 to 0.08% by weight, a water content of ≦0.20% by weight, particularly preferably ≦0.10% by weight, e.g. from 0.01 to 0.08% by weight, and an APHA color number of ≦20, particularly preferably ≦15, very particularly preferably ≦10, e.g. from 2 to 8. [0097] The process of the invention is also particularly advantageous for preparing N-ethylmorpholine (E-MO) having a purity of ≧98.50% by weight, particularly preferably ≧99.00% by weight, e.g. from 99.50 to 99.90% by weight, [0000] a water content of ≦0.30% by weight, particularly preferably ≦0.20% by weight, e.g. from 0.05 to 0.15% by weight, and an APHA color number of ≦50, particularly preferably ≦20, very particularly preferably ≦10, e.g. from 2 to 8. [0098] APHA color numbers are determined in accordance with DIN EN 1557. [0099] The water content is determined in accordance with DIN 51777 (K. Fischer). [0100] The chloride content is determined by means of ion chromatography (detection of conductivity with chemical suppression), using the following method: [0000] Sample preparation: about 2 g of sample are weighed into a volumetric flask (10 ml) and made up to the mark, with eluent. Measurement conditions: Ion chromatography system: Metrohm Modulares System (733) Preliminary column:e.g. DIONEX AG 12; separation column: e.g. DIONEX AS 12 Eluent: e.g. 2.7 mmol of Na 2 CO 3 , 0.28 mmol/l of NaHCO 3 in water Flow: 1 ml/min; injection volume: 100 μl Detection: conductivity after chemical suppression Suppressor: Metrohm Modul 753 [0101] Regenerent: 50 mmol of H 2 SO 4 in high-purity water (flow about 0.4 ml/min) Calibration: external, checked by standard addition experiments Determination limit: 0.1 mg/kg of chloride in the sample. [0102] In the desired product morpholine, the content of morpholine, 1,2-ethylenediamine, N-ethylmorpholine, 2-methoxyethanol is determined by means of GC (GC conditions: 30 m DB-1; temperature program with 60° C. initial temperature, 4° C./min heating rate, 190° C. final temperature). [0103] In the desired product ADG, the content of ADG and DEG is determined by means of GC (GC conditions: 30 m DB1, temperature program with 100° C. initial temperature, 8° C./min heating rate, 250° C. final temperature). [0104] In the figures: [0105] FIG. 1 shows, inter alia, the isolation of MO and ADG according to the invention by means of a 7-column arrangement. [0106] FIG. 2 shows, inter alia, the replacement of the columns K 60 -K 70 of the 7-column arrangement by a dividing wall column (DWC). [0107] FIG. 3 shows, inter alia, a particular embodiment of the dividing wall column K 60 in which the dividing wall (DW) extends to the bottom of the column. [0108] FIG. 4 shows, inter alia, the isolation of MO and ADG according to the invention by means of an 8-column arrangement. [0109] FIG. 5 shows, inter alia, the 7-column arrangement as used in the example, including recycle streams and synthesis part and heat integration (B 1 =high-pressure separator, B 2 =intermediate-pressure separator, C 1 =reactor, V 1 =compressor, W 1 , 2 , 3 and 4 =heat exchangers). [0110] HB=high boilers, LB=low boilers, IB=intermediate boilers, WWT=wastewater requiring treatment. EXAMPLES Example 1 See FIG. 5 [0111] Diglycol (DEG) is mixed with the bottom product from the column K 70 (main components: diglycol and morpholyl-ADG) and the overhead products from the columns K 60 and K 70 (main components: aminodiglycol, (2-aminoethyl)morpholine and 2-(2-aminoethoxy)ethylamine) and fed continuously to the heat exchanger W 1 . [0112] Liquid ammonia is mixed with recirculated ammonia from the column K 10 and fed continuously to the heat exchanger W 1 . [0113] Both streams are mixed with the recycle gas consisting predominantly of hydrogen upstream of the heat exchanger W 1 . The recycle gas is brought from the high-pressure separator B 1 located at the outlet from the synthesis by means of the compressor V 1 . After the heat exchanger W 1 , the mixture which has a temperature of 140° C. is heated to 175° C. by means of a heater W 2 and conveyed to the reactor C 1 . The reaction of the diglycol to form aminodiglycol and morpholine takes place over the fixed-bed catalyst there at a pressure of 200 bar and temperatures up to 215° C. The output from the reactor is then cooled to 45° C. in the heat exchangers W 1 , W 3 and the air cooler W 4 . In the high-pressure separator B 1 ; separation into a gas phase and, a liquid phase occurs. The gas phase is, as described above, conveyed as recycle gas to the heat exchanger W 1 . [0114] The liquid phase from the high-pressure separator B 1 is depressurized to 25 bar into the intermediate-pressure separator B 2 . The gas liberated there from the effervescing liquid is conveyed into an absorber to recover NH 3 . The amount of hydrogen to be replaced, is taken from the network and introduced into the feed to the synthesis. [0115] The reaction mixture then goes from the intermediate-pressure separator B 2 via the heat exchanger W 3 to the column K 10 . Ammonia Removal (K 10 ) [0116] In the column K 10 , the ammonia is distilled off at a purity of >99.9% from the feed at a pressure at the top of 16 bar abs. and recirculated to the reactor inlet. The offgas is connected to an absorber. The ammonia-free bottoms having a temperature of 220° C. are depressurized into the column K 20 for the removal of water. K 10 has 17 theoretical plates and the feed point is at plate 14 . Water Removal (K 20 ) [0117] In the column K 20 , the water of reaction is separated off at atmospheric pressure. The distillate, which comprises 98% by weight of water and 2% by weight of low boilers (predominantly ethylmorpholine), is fed to the column K 50 . In addition, the overhead product of the pure morpholine distillation K 40 (main components: 1,2-ethylenediamine, morpholine and water) is fed to the column K 20 . The largely water-free bottoms from K 20 are depressurized at a temperature of 158° C. (main components: morpholine, aminodiglycol, diglycol and high-boiling residue) into the column K 30 . K 20 has 56 theoretical plates and the feed point is at plate 25 . LB/HB Removal (K 30 ) [0118] In the column K 30 , the feed comprising the bottoms from the column K 20 and the recirculated bottoms from the pure distillation K 40 is separated at a pressure at the top of 550 mbar into a low-boiling fraction (main component: morpholine) and a high-boiling fraction having a bottoms temperature of 213° C. (main components: aminodiglycol, diglycol and high-boiling residue). The bottoms are fed to the column K 60 . The condensate comprising 95% by weight of morpholine, 4.5% by weight of 1,2-ethylenediamine and 2-methoxyethanol and water is fed to the column K 40 . K 30 has 17 theoretical plates and the feed point is at plate 13 . Pure Morpholine Distillation (K 40 ) [0119] In the column K 40 , morpholine having a concentration of >99.6% by weight of morpholine and a 1,2-ethylenediamine (EDA) content of <0.10% by weight is separated off in gaseous form at a side offtake at a pressure at the top of 2.2 bar abs . The overhead distillate (main components: 1,2-ethylenediamine, morpholine and water) is recirculated to K 20 or, after concentration of ethylenediamine, discharged discontinuously via a container. The bottoms from the column K 40 (morpholine together with higher-boiling secondary components), which have a temperature of 160° C., go back to K 30 . K 40 has 42 theoretical plates, the feed point is at plate 18 and the side offtake is at plate 3 . Ethylmorpholine Distillation (K 50 ) [0120] In the column K 50 , N-ethylmorpholine is separated off from the feed as an azeotrope with water at atmospheric pressure. The bottoms from the column, which have a temperature of 103° C., are discharged. K 50 has 21 theoretical plates and the feed point is at plate 11 . Residue Removal (K 60 ) [0121] In the column K 60 , aminodiglycol and diglycol are separated off together from the feed as a liquid side offtake stream at a pressure at the top of 60 mbar and are conveyed to the column K 70 . The distillate from the column (main components: aminoethoxyethylamine, aminoethylmorpholine, aminodiglycol) is recirculated to the reactor inlet. The bottoms from the column, which have a bottoms temperature of 204° C., are discharged from the process. K 60 has 42 theoretical plates, the feed point is at plate 20 and the side offtake is at plate 36 . Aminodiglycol Distillation (K 70 ) [0122] In the column K 70 , aminodiglycol having a purity of >98.0% by weight and a water content of <0.10% by weight is separated off from the feed as a liquid side offtake stream at a pressure at the top of 80 mbar. The condensate from the column (main components: aminodiglycol, (2-aminoethyl)morpholine and 2-(2-aminoethoxy)-ethylamine) is recirculated to the reactor inlet. The bottoms from the column (87% by weight of DEG, 11% by weight of morpholyl-ADG and 2% by weight of high boilers), which have a bottoms temperature of 238° C., are likewise recirculated to the reactor inlet. K 70 has 42 theoretical plates, the feed point is at plate 25 and the side offtake is at plate 35 . [0123] The numbering of the plates in the columns is from the bottom upward.

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    US-8674140-B2March 18, 2014Basf SeDevices and method for continuous distillative separation of a mixture containing one or more alkanolamine(s)
    US-9345988-B2May 24, 2016Basf SeDevices and method for continuous distillative separation of a mixture containing one or more alkanolamine(s)