WO-2008148661-A1 Method for producing cyclopentanone Basf Se 2007-06-04 Abstract The invention relates to a method for producing cyclopentanone. Said method comprises the step of reacting a mixture (G1), which contains at least cyclopentene, with a mixture (G2), which contains at least dinitrogen monoxide. The reaction is carried out in at least one reactor (R1) having channels with a diameter in the range of 0.1 mm to 50 mm, the reactor comprising at least two zones (Z1) and (Z2) having channels with different diameters and the diameters of the channels of zone (Z1) being smaller than the diameter of the channels of zone (Z2). Preferably, the reaction is carried out at a pressure of 200 to 500 bar, preferably at 220 to 450 bar, in particular at 240 to 400 bar, particularly preferably at 260 to 350 bar, for example at 265 bar, 270 bar, 275 bar, 280 bar, 285 bar, 290 bar, 295 bar, 300 bar, 305 bar, 310 bar, 315 bar, 320 bar, 325 bar, 330 bar, 335 bar, 340 bar or 345 bar. According to a preferred embodiment, the reaction is carried out in the temperature range between 270 and 300 0 C and at a pressure of 260 to 350 bar, in particular 280 bar. The reaction conditions are preferably selected such that the N 2 O conversion is more than 80% and the cyclopentene conversion is more than 50%. (Comparative Example): Reaction in the tubular reactor Example 1 was carried out in a reactor with flash and distillation stage downstream. The reactor consists of a series of 16 individual tubes (outer diameter = 10 mm, wall thickness = 2 mm, inner diameter = 6 mm, length = 5.3 m) wound spirally (radius r = 125 mm, pitch P = 30 mm) , The reaction volume including connectors is 2510 ml in total. The tube is provided with a double jacket (outer tube: outer diameter = 20 mm, wall thickness = 2 mm, annular gap width = 3 mm) through which a cooling liquid is pumped in cocurrent to dissipate the heat of reaction (Marlotherm SH from Sasol). The temperature of the incoming cooling medium is set to 280 ± 2 ° C with an external thermostat. Directly at the outlet of the reactor is a pressure maintenance, which keeps the pressure in the reactor constant at 280 bar. The fresh cyclopentene is metered into the reactor at 172.5 g / h. Cyclopentene originates from the distillation of a C 5 cut of a steam cracker and has the following composition (% by weight): cyclopentene (about 93.2%), cyclopentane (about 5.7%), 2-methyl-2-butene (about 1, 1%), 2,2-dimethylbutane (about 0.17%). By mixing this stream with a cyclopentene recycle stream, a stream of the following composition is produced: cyclopentene (about 48.8%), cyclopentane (about 46.2%), 2-methyl-2-butene (about 3.1%). ), Acetone (about 2.0%), 2,2-dimethylbutane (about 0.96%). This stream is then metered to the reactor with a metering pump (flow rate: 1632 g / h). As a further stream of liquid N 2 O (content of N 2 O> 99.5 vol .-%, Messrs. Messer Griesheim) is metered at about 99.2 g / h to the reactor. The molar ratio of cyclopentene to N 2 O in the reactor feed is 0.192 mol / mol. The cyclopentene conversion in the straight pass is 19.6% and the N 2 O conversion is about 99.6%. The reactor discharge is relaxed after pressure maintenance in two steps with two at 1 1 bara and 1, 1 bara operated flash vessels to 1, 1 bara and cooled. The gaseous components are separated and in an aftercooler (operated at + 5 ° C) hydrocarbons contained therein are condensed out as completely as possible. The gas phase (about 64.5 g / h) has the following composition: N 2 (96.4% by volume), N 2 O (0.41% by volume), ethylene (0.28% by volume). ), Cyclopentene (0.37% by volume), cyclopentane (0.33% by volume), other C 5 components (545 vppm). The liquid phase obtained is separated in a distillation column (bubble-cap column with 5 column sections 106 cm × 50 mm, 10 plates each). The bottom product obtained is 187.7 g / h of a stream having the following composition (wt .-%): cyclopentanone (about 96.8%), cyclopentane (about 1, 3%), 4-pentenal (ca. 1.3%), isopropyl methyl ketone (about 0.8%), cyclopentene oxide (about 0.5%), cyclopentene dimers (about 0.5%), cyclopentene (about 0.03%). From the top product, which contains 43.4% cyclopentene but no cyclopentanone, about 14.9 g / h are discharged to avoid the accumulation of minor components, in particular acetone and 2-methyl-2-butene. The remainder (about 1460 g / h) is returned as a cyclopentene recycle stream to the mixer with fresh C5. After this procedure, the space-time yield is about 72.4 g cyclopentanone / liter reaction volume / hour. For each kg of cyclopentanone produced, about 8.2 kg of cyclopentene / cyclopentane mixture must be separated off and recycled for the most part. The energy required for the distillation is 0.73 kWh / kg of cyclopentanone. Example 2: Reaction in the microreactor Example 2 was carried out analogously to Example 1, wherein the tubular reactor was replaced by a microreactor and in addition a post-reactor was used. The reactor was manufactured by the company Heatric (Vessel title: Demonstration Mixer Reactor, Plant Item No .: E100, Year built: 2005, Client: BASF, Client PO No .: 1086229765/306 / D, Serial No .: H1016A, Type: PCR). The main reactor consists of 48 316 / 316L stainless steel plates with 338 x 188 * 1, 9 mm in which semicircular channels were created and then diffusion welded into a single block. The finished reactor has the following dimensions: 338 x 188 x 91 mm. The two starting m The finished reactor has the following dimensions: 338 x 188 x 91 mm. The two starting materials are fed through separate inlets and first divided in the entry zone (upper plate) and then mixed. The available reaction volume in this main reactor is about 194 ml distributed over 10 plates. In these plates there are two parallel product-carrying channels which are semicircular and have a radius of 1, 2 mm (cross-sectional area: 2.262 mm 2 ). The channels are arranged in parallel on each plate and undercut 49 passages on each plate. The total length of each channel is thus about 45 m. Coolant is pumped through the cooling circuit at a rate of approx. 16 l / min to dissipate the heat of reaction (Marlotherm SH from Sasol). The temperature of the incoming cooling medium is set to 280 ± 2 0 C with an external thermostat. The secondary reactor used is two pipe coils connected in series, which are also operated at 280 ± 2 ° C. These coils have the same dimensions as those of the reactor used in Example 1. The total available reaction volume (including connecting pieces) is approx. 530 ml_. At the outlet of the last reactor is a pressure maintenance, which keeps the pressure in the reactor and post reactor constant at 280 bar. The fresh cyclopentene feed is metered in at 205.4 g / h. This comes from the distillation of a Cs-section of a steam cracker and has the following composition (wt .-%): cyclopentene (about 94.7%), cyclopentane (about 4.5%), 2-methyl-2-butene ( about 1.0%), 2,2-dimethylbutane (about 0.14%). Mixing this stream with a cyclopentene recycle stream produces a stream having the following composition: cyclopentene (about 92%), cyclopentane (about 6.9%), 2-methyl-2-butene (about 1.9%) , 2,2-dimethylbutane (about 0.32%), acetone (about 0.18%). This stream is then metered with a metering pump to the reactor (input N 2 O, flow rate: 300 g / h). Liquid N 2 O (content of N 2 O> 99.5% by volume, from Linde) is added separately to the reactor at 129.2 g / h. The molar ratio of cyclopentene to N 2 O in the reactor feed is about 0.72. The cyclopentene conversion in the straight pass is 65% and the N 2 O conversion is about 92%. The reactor discharge is relaxed after pressure maintenance in two steps with two at 11 bara and 1, 1 bara operated flash vessels to 1, 1 bara and cooled. The gaseous components are separated and in an aftercooler hydrocarbons contained therein are condensed out as completely as possible. The gas phase (about 88.8 g / h) has the following composition: N 2 (89.4% by volume), N 2 O (7.92% by vol.), Ethylene (790 vppm), cyclopentene (1 , 1 vol.%), Cyclopentane (0.21 vol.%), Further C 5 components (803 vppm). The liquid phase is separated in a distillation column (bubble-cap column with 5 column sections 106 cm × 50 mm, 10 plates each). The bottom product obtained is 229 g / h of a stream having the following composition (wt .-%): cyclopentanone (about 92.3%), cyclopentane (about 3.1%), 4-pentenal (about 1, 1% ), Isopropyl methyl ketone (about 0.34%), cyclopentene oxide (about 0.5%), cyclopentene dimers (about 0.25%), cyclopentene (about 0.19%). From the overhead product containing 84.8% cyclopentene but no cyclopentanone, about 15.4 g / h are discharged to avoid accumulation of minor components, in particular acetone and 2-methyl-2-butene. The remainder (about 95 g / h) is returned to the reactor as a cyclopentene recycle stream. After this procedure, the space-time yield is about 399 g cyclopentanone / liter reaction volume / hour. Thus, it takes 5.5x less reaction volume for the same amount of product. In addition, only 0.52 kg cyclopentane / cyclopentane mixture must be separated and partially recycled per kg of cyclopentanone produced instead of 8.2 kg according to Example 1. The energy required for this purpose is only 0.09 kWh / kg cyclopentanone instead of 0.73 kWh / kg according to Example 1. Example 3: Reaction in the microreactor Example 3 was carried out analogously to Example 2, but without the coils as a post-reactor. Coolant is pumped at approx. 16 l / min in the cooling circuit in order to dissipate the heat of reaction (Marlotherm SH from Sasol). The temperature of the incoming cooling medium is set to 280 ± 2 0 C with an external thermostat. The total available reaction volume (including connectors) is approx. 201 ml_. At the outlet of the last reactor is a pressure maintenance, which keeps the pressure in the reactor constant at 280 bar. The fresh cyclopentene feed is metered in at 154 g / h. This originates from the distillation of a C 5 cut of a steam cracker and has the following composition (% by weight): cyclopentene (about 94.9%), cyclopentane (about 4.2%), 2-methyl-2 -butene (about 1.0%), 2,2-dimethylbutane (about 0.04%). This stream is first mixed with a cyclopentene recycle stream to produce a stream having the following composition: cyclopentene (about 93.1%), cyclopentane (about 4.3%), 2-methyl-2-butene ( about 2.3%), 2,2-dimethylbutane (about 0.09%), acetone (about 0.41%). This stream is then metered to the reactor with a metering pump (inlet N2, flow rate: 268 g / h). Liquid N 2 O (content of N 2 O> 99.5% by volume, from Linde) is added separately to the reactor at 123 g / h (input N1). The molar ratio of cyclopentene to N 2 O in the reactor feed is about 0.72 mol / mol. The cyclopentene conversion in the straight pass is 54% and the N 2 O conversion is about 76%. The reactor discharge is relaxed after pressure maintenance in two steps with two at 11 bara and 1, 1 bara operated flash vessels to 1, 1 bara and cooled. The gaseous components are separated and in an aftercooler hydrocarbons contained therein are condensed out as completely as possible. The gas phase (about 61.7 g / h) has the following composition: N 2 (81.7 vol.%), N 2 O (17.7 vol.%), Ethylene (674 vppm), cyclopentene (0 , 4% by volume), cyclopentane (402 ppm), further C 5 components (346 vppm). The liquid phase is separated in a distillation column (bubble-cap column with 5 column sections 106 cm × 50 mm, 10 plates each). The bottom product obtained is 165.4 g / h of a stream having the following composition (% by weight): cyclopentanone (about 93.8%), cyclopentane (about 3.0%), 4-pentenal (ca. 1.3%), cyclopentene oxide (about 0.5%), cyclopentene dimers (about 0.25%), cyclopentene (about 0.9%). From the top product, which contains 91.1% cyclopentene but no cyclopentanone, about 8.1 g / h are discharged in order to avoid accumulation of secondary components, in particular acetone and 2-methyl-2-butene. The remainder (about 14 g / h) is returned to the reactor as a cyclopentene recycle stream. After this procedure, the space-time yield is about 823 g cyclopentanone / liter reaction volume / hour. Thus, for the same amount of product 11, it takes four times less reaction volume than in example 1. In addition, only 0.11 kg of cyclopentene / cyclopentane mixture per kg of cyclopentanone produced have to be separated off and partly recycled instead of 8.2 kg According to Example 1. The energy required for this purpose is only 0.09 kWh / kg of cyclopentanone instead of 0.73 kWh / kg according to Example 1.