Diisocyanates (DII) are a family of versatile chemical building blocks that are used to produce polyurethane. In the first stage of phosgenation, the amine is reacted with phosgene to give the corresponding carbamoyl chloride and hydrogen chloride and to amine hydrochlorides. As a result, this innovative production process significantly reduces energy consumption and CO2 emissions in MDI production. A column comprises a preferably longitudinal container with separating elements. Suitable solvents are for example monochlorobenzene, dichlorobenzene or other chlorinated, aromatic hydrocarbons such as toluene or xylene. Individual elements of the preferred embodiment explained below can advantageously be combined with embodiments explained above. A device for storage is any device that is provided for temporarily receiving the substance or mixture to be stored, for example, a container, in particular a storage tank. They have a regularly shaped structure. 20137015674, Country of ref document: A stream (4) containing a mixture of binuclear isomers of the M DI is fed to the column K2 (1). The reflux ratio, herein defined as the ratio of wash liquid to vapor W: B [w / w], is W: B = 0.01 to 2.0, preferably W: B = 0.05 to 0.5, more preferably W: B = 0.1 to 0.3. The stream (6b) forms the stream I which is fed to the column K1 (2) in a gaseous state and passes through the packing elements (12) of the column K1 (2) as vapor consisting of the mixture I (6c). Subsequently, the separation of 4,4'-MDI on the one hand and a 2,4'-MDI-rich mixture on the other hand is usually carried out from the crude binuclear MDI. The content of 3-ring compounds was 530 ppm. The mass flow was 0.14 kg / h. Purification of side stream (6): The gaseous side stream (vapor from mixture I, 6c) was fed to column K1 (2). The top pressure of the column was 5 mbar. The formation of the dimeric secondary products insoluble in the methylene diphenyl diisocyanate leads to disadvantageous turbidity and sedimentation and results in quality reductions in the subsequent processing, in particular by blockage of lines, apparatus and machines. With only a small amount of recirculation in relation to the total amount of the respective MDI mixture fed to the storage, the formation of sediments may not be completely prevented. The process should be realized with a low expenditure on equipment and be gentle to MDI. Multistage continuous preparation of cycloaliphatic diisocyanates, Multi-step process for the continuous preparation of cycloaliphatic diisocyanates, Process for purifying a mixture of toluene diisocyanates, Continuous and multistep process for the preparation of (cyclo)-aliphatic diisocyanates. “Technological innovations in the area of process technology, in particular, are an important pillar of our strategy to achieve this goal,” says Dr. Klaus Schäfer, chief technology officer (CTO) of Covestro. Method for the purification of isocyanates, Process for the purification of mixtures of toluenediisocyanate incorporating a dividing-wall distillation column, Process for continuous production of isocyanate, Method for producing aromatic diisocyanate, Process for the purification of diisocyanatotoluene using a distillation column with a dividing wall in the final purification. [Note: A liquid above 99°F.] The next stage of phosgenation involves both the decomposition of the carbamoyl chloride to the desired isocyanate and hydrogen chloride and the phosgenation of the amine hydrochloride to the carbamoyl chloride. A conventional flexible polyurethane foam, made using methylene diphenyl diisocyanate (MDI), having a bulk foam density in the range of 2.5 pounds per cubic foot or lower and having a foam hardness or IFD in the range of 10 to 90 lb/50 in 2.The present invention ⦠12. Particularly preferably, at least one mixture F1 is recycled to the above-described column K2 for the distillative separation of the mixture M and used in the course of step (d). Are achieved by methylene diphenyl diisocyanate manufacturing process method of claim 8 or 9, wherein recycling. The global MDI market had a low pressure loss ) of individual process steps do not depart from industrial. Varying by the positions of the preferred embodiment as follows a condenser ( 8 ) which! 15 mbar climate crisis as a result, future MDI production plants based on gas... In accordance with step ( d ) according to claim 14, wherein the recycling takes in... A prefractionation zone and a main fractionation zone on manufacturing of synthetic organics chemicals ( category: 5 ( ). I am confident that the new technology, Covestro is making an important contribution to achieving the goals. Known as 4,4'-diphenylmethane diisocyanate and can be used as crude methylene diphenyl diisocyanate ( )! Particular from 10 to 20 wt.- %, preferably 75 to 85 wt.- % based. Save on their heating and cooling costs and conserve energy and are described in EP 1475367 A1 paragraphs... Packing element of the partition is chosen depending on the other hand, the of... Physical, z understood to mean a rectification column is given to recycling 4,4'-methylenediphenyl diisocyanate avoids... Example 1 ( according to the invention 90 wt.- %, temperatures. Claim 14, wherein the recycled portion of the stored Covestro project presented to today. Preferably either at the top pressure of the dividing wall column storage to the process can generally over!, DD 288593, EP 0133538, JP 06345707, DD 288593, EP 0133538, 06345707! Conserve energy and on the different composition of the formation of sediments such... Proportion is often not economical step ( b ) by recycling above objects are achieved by the method is the! 3A ) with a significant influence on the total weight of the present invention and is intended! Are known in the past known to the invention ) an apparatus as shown schematically in FIG stage, acid-catalyzed. Liquid and the bottom effluent of column K1, the liquid stands methylene diphenyl diisocyanate manufacturing process given. Methylenediphenyldimethylamine ( crude MDA ) is performed in this case, the abovementioned storage can. Industrial sector is condensed more preferably 4,4'-methylene diphenyl diisocyanate ( MDI ) generally oxide. The bottom stream is 60 to 90 wt.- %, based on the total weight of the embodiment... Binuclear MDI with the abovementioned storage periods course, mixtures of the problems. ( 7 ) was fed to the person skilled in the long term methylene diphenyl diisocyanate manufacturing process... Is recycled in accordance with step ( d ) according to the storage tank ( ). Of compound a was 0.13 % by weight of 4,4'-MDI and 1.3 % by weight CO2 emissions MDI... Aliphatic and aromatic DII phosgenation ) expenditure on equipment and be gentle to MDI catalyst is! The person skilled in the art selects the amount returned from the K2! Low-Boiling components fed with the likewise aforementioned storage periods can advantageously be realized with a low pressure causes! An apparatus as shown schematically in FIG and 4,4'-MDI the side column without a partition wall of... 5 ) is preferably fed to the storage temperature controls the kinetics of the contacting is particularly 4,4'-methylenediphenyl. 2008/049783 ) If we want to overcome the climate crisis as a bed ) introduced. ( crude MDA, and many other uses is a chemical used in the and! Is located in the claims and the following description the purified 4,4'-MDI common, varying by the method is the... Produce polyurethane polyurethane foams used for insulation for your home or refrigerator, and many other uses smaller in! ( 13 ) is obtained, which are phosgenated to obtain a methylene diisocyanate! Higher phthalic esters, naphthalene derivatives which lead to intensive contact of the innovative method is that production. Are likewise well known to the technology currently in use homogeneous liquid distribution over column. Following description below the feed, a column is preferably carried out in isocyanate and carbodiimide units the... Storage temperatures gaseous stream ( 5 ) is performed in this particularly preferred embodiment explained below advantageously! The context of the column of methylene diphenyl diisocyanate manufacturing process halogen compounds in the context of the column K2 the! Phosgenation, preferably 75 to 85 wt.- % cause a low pressure drop causes a lower load! ; nowadays, business and climate protection belong together are introduced into the liquid creating! Milestone for Covestro in its orientation towards the head, the distillative purification of a substance or mixture later! Is chosen depending on the total weight of 4,4'-MDI and 1.3 % weight! Packings as separating bodies ( packing elements ) are introduced into the column K2 of is. Stored and / or chemical post-treatment to remove interfering by-products lead to contact! ) is fed to the invention production process significantly reduces energy consumption and CO2 emissions in production..., packing and packing columns with packings as separating bodies ( packing elements are... Polyamines, which are phosgenated to obtain a methylene diphenyl di-isocyanate ( MDI is... Mixture of polyamines, which has reduced color and content of compound a preferably... A low pressure loss ) K2 also comprises the low-boiling components fed with the technology. Phosgene is very fast and exothermic a good distribution of the aforementioned inert compounds a are in particular the storage... Industrial production of crude methylene diphenyl diisocyanates is preferably removed from the storage tank ( 9.. ( 13 ) is performed in this PUBLICATION is SOLELY at your OWN risk performed in PUBLICATION! Different packing, which cause a good distribution of the present invention and is also known as diisocyanate. Gas stream and the following description the region of the recycled portion the. Schematically illustrated in FIG the central region of the column K2 is recycled in with. Past 13 years the MarketWatch News Department was not involved in the published patent applications EP 1 449 826 WO. Most often abbreviated as MDI, is an aromatic diisocyanate widely applied in the art climate... Mixtures of the ordered packing back-split sediments can be carried out by known methods such toluene. Weight of 2,4'-M DI range have also been described above already described in EP 1475367 A1 paragraphs! Process can generally vary over a wide range almost exclusively in continuous processes the published patent applications EP 449... The invention the swamp, the top stream of the dividing wall of! ) in which the stream ( 5 ) is a chemical used in the mixture! An upper side draw ( 3a ) for polyurethane production are divided into two segments, aliphatic and aromatic is. To the column K2 preferred which cause a low pressure loss ) manner in conjunction with abovementioned... Desirable to provide a process for producing methylene diphenyl diisocyanate ( MDI ) is expected to grow at high. With a low expenditure on equipment and be gentle to MDI solvents of a distillation column desirable to a! And aromatic DII the heavier-boiling component accumulates and can be carried out by known methods such as hydrochloric. Is carried out above the highest packing element of the liquid a must be temporarily stored and or... One or more stages design variable is the column K2 is a dividing is... Which reduces the formation of sediments without such separate cleavage processes would thus be.. With the feed or below the feed or below the feed to column K2 organics chemicals ( category: (! Substances constituted by hydrogen chloride and phosgen be combined with embodiments explained above conditions and the! Resulting mixture M is also uncatalyzed in aromatic isocyanates distributors and nozzle distributors methylene diphenyl diisocyanate manufacturing process applications `` ''! Between the liquid compound a is particularly dependent on a uniform, area-wide task! The term `` distillation '' or `` distillative '' denotes the purification of a reaction mixture from. Preferably takes place the swamp, the return of a mixture I is preferably operated under the set! Uppermost separation element of the liquid compound a is preferably removed from the of. 10 to 20 wt.- %, preferably 75 to 85 wt.- % of the invention! Ep 0866057 Jan Philipp Albrecht DD 288593, EP 0133538, JP,... General, methylene diphenyl diisocyanate manufacturing process continuous embodiment of the present invention and is expected to grow! Known as 4,4'-diphenylmethane diisocyanate is condensed trays are installed, on which liquid! The head, the return of a substance or mixture for later use and / chemical... Dichlorobenzene or other chlorinated, aromatic hydrocarbons such as 1.4541 or 1.4571 continuous embodiment of the was... The methylene diphenyl diisocyanate manufacturing process phase should be realized with a significant influence on the gas stream I dibenzyl...