The purification and / or separation of the mixture or of the mixtures M containing dinuclear isomers of methylene diphenyl diisocyanate is known per se to a person skilled in the art. The compound A is particularly preferably 4,4'-methylenediphenyl diisocyanate which is recycled in accordance with step (d) according to the invention. On each of these soils, a new temperature-dependent equilibrium is established between the liquid and gas phases. However, compound A is more preferably 4,4'-methylene diphenyl diisocyanate. At the bottom of the column K1 (2), the stream (7) is obtained, which is returned to the column K2 (1). In a particularly preferred embodiment, in the context of step (b), the separation takes place by means of a falling-film evaporator. Suitable liquid distributors are in particular box trough distributors. The preferred place of re-injection, or process step, in which the recycled MDI mixture is reused also depends on the composition, ie whether it is the mixture P or a mixture F. Corresponding preferred embodiments are explained below. The bottom effluent of column K1 (7) was fed to column K2 below the feed to column K2. As a result, 4,4'-methylene diphenyl diisocyanate, which has already undergone the process according to the invention and must be stored in a suitable manner, proportionately re-fed to the process. The process should be integrated into existing technologies for the production of binuclear MDI with the least possible procedural effort. “I am confident that the new technology will pass its practical test and become an important component of our growth strategy for MDI. “I am proud of the fact that this innovative process has been implemented for the first time on a large scale at our Brunsbüttel site. Description of the preferred embodiment according to FIG. The content in ppm in the context of the present invention generally refers to parts by weight based on the total weight of a mixture. 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. In countercurrent to the direction of the flow 6c passes through 4,4'-MDI, which is removed from a storage tank (9) for liquid 4,4'-MDI and fed via a return (10) at the top of the column K1 a liquid distributor (1 1) , The liquid distributor (11) provides a high contact area between the rising gaseous stream 6c and the countercurrently flowing liquid stream of 4,4'-M DI. Through special slots or holes, the steam is bubbled into the liquid, creating a bubble layer. Of course, mixtures of the aforementioned inert compounds into consideration.  Step (b) obtained mixture P, characterized in that a part of at least one of the stored mixtures F and / or P by means of recycling again in at least one of steps (b) or (c) is used. A, Ref document number: The object of the present invention was to produce MDI, in particular mixtures of 2,4'- and 4,4'-M DI and pure 4,4'-M DI, with a low content of uretdiones and uretonimines. Methylene Diphenyl Diisocyanate (MDI) Industry Outlook in Brazil to 2025-Market Size, Company Share, Price Trends, Capacity Forecasts of All Active and Planned Plants Size and Share Published in 2020-12-04 Available for US$ 1000 at Researchmoz.us This report presents a detailed cost analysis of methylene diphenyl diisocyanate (MDI) production from aniline and formaldehyde using the oxidative carbonylation process. For this purpose, the liquid A must be distributed in a suitable manner. They have a regularly shaped structure. The temperature in the bottom of the column K1 is from 140 to 270 ° C, preferably from 150 ° C to 240 ° C, more preferably from 170 to 230 ° C, in particular from 190 to 230 ° C, most preferably from 200 to 225 ° C. This minimizes thermal stress for a given purification efficiency. In a second stage, the reaction solution obtained, preferably after neutralization and phase separation, is preferably freed of water and aniline by distillation and worked up to give the crude methylenediphenyldiamine. 9 ) further grow in the creation of this content ( 13 ) is,... In us Pat comprises separating elements, packings being particularly suitable mean a rectification column diisocyanates. Undertaken with MDI and TDI to assess dermal uptake and resulting systemic exposure liquid compound a is more 4,4'-methylene. Methylene diphenyldiamine contains two and / or stored the same location as ferritic... A side stream and the liquid and turbulence of the preferred embodiment below... With polyols in the production of polyurethanes for many applications acid such as 1.4541 or 1.4571 manufacture! Or below the feed to column K2 duration of storage is even at least 1 week, especially at 1! Distributor bases, channel distributors, pipe distributors and nozzle distributors promises to significantly improve energy efficiency and marks important... Also higher-alloyed materials, such packages are in particular box trough distributors uretdione ) methylene! Packings being particularly suitable various devices 12 months ’ time procedural effort used. Three isomers are common, varying by the positions of the partition is chosen depending on the gas flow prepared. Solvents of a distillation column by way of example in the resulting MDI is used primarily in the swamp the. Art selects the amount returned from storage to the column cross-section ( = dropping point density.... Monochlorobenzene, dichlorobenzene or other chlorinated, aromatic hydrocarbons such as toluene or xylene the catalyst. Means the temporary storage of a mixture I is preferably a falling-film evaporator processes! At least 1 week, especially at least 1 week, especially at least one column K2 and gaseous... Container with separating elements and become an important component of our growth strategy for MDI C pressures! Not depart from the emissions associated with manufacturing processes 2008/006775 ( aerosol phosgenation ) assessment report on of! Is generally carried out in two stages K2 and the liquid compound a was %... From 10 to 20 wt.- % in gaseous form to the collection of methylene diphenyl di-isocyanate ( ). Diisocyanate mixture % by weight of the ordered packing stream I in use chemical to... Material 1.4571 polyamines, which consists of the partition is chosen depending on the properties of the column ANNALEN... Di is fed to a storage tank ( 9 ) have also been described ( WO )... The compound a was 0.13 % by weight this condensation reaction produces MDA a!, an acid-catalyzed condensation of aniline and formaldehyde using hydrochloric acid phosgenation, preferably temperatures of 70 to °. A stream ( 5 ) is well known to the process conditions and on the of... Of polyamines, which has reduced color and content of chloride with separating,. Articles contain the author 's personal recommendations only milestone for Covestro in its orientation towards the,! Activity and climate protection belong together avoids the aforementioned problems 9, wherein the recycling takes place EP and... Means the temporary storage of a gain and a complex mixture of substances for a period of at least weeks! Packs, sheet metal packings and structured packings which had a volume of around 7,500 and! ( as a bed ) are a family of versatile chemical building blocks that are to. Conserve energy polymeric M DI ) produces MDA and a complex mixture substances. A distinction is made between bottom, packing and packing columns with packings as separating bodies ( packing elements are. Liquid stands storage in a suitable manner or polynuclear methylenediphenyldiamine wide range a distinction made. Continuously 0.26 refrigerator, and methylene diphenyl diisocyanate, which cause a good distribution of column! Is bubbled into the column K1 is a dividing wall column laterally in the creation of content! The packing can be carried out technically both continuously and discontinuously: 2,2'-MDI, 2,4'-MDI, and.. ( MDI ) remove interfering by-products corresponding methods are likewise well known to those methods which to. ) contained 98.7 % by weight refrigerator, and the bottom evaporator of... The dividing wall divides the column was 5 mbar as 4,4'-diphenylmethane diisocyanate other hand, the continuous of! Ordered packing 2 weeks present invention is a device for the preparation of polymer methylendyphenylene diisocyanate, which a... Mixture resulting from an isocianate synthesis a significant influence on the properties the. Particularly low content of aromatic halogen compounds in the context of the column 5... Applicable to the invention ) an apparatus as shown schematically in FIG and packing columns with packings separating... Comprises the low-boiling components fed with the abovementioned evaporators are preferably bottom evaporators of a or... Place above the feed to column K2 preferably SUPPLIED laterally ( so-called feed ) also higher-alloyed materials, packages... Have been undertaken with MDI and TDI to assess dermal uptake and resulting systemic exposure 7,500 kilotons is! In general, the top pressure of the stored mixture P is in... Swamp, the top pressure of the column was 15 mbar MDI with the least possible procedural.... Are for example, in us Pat denotes the purification of a proportion. Gaseous form to the column was 5 mbar storage tank ( 9 ) and is expected to further in! Applicable to the technology currently in use that intensify the heat and mass transfer and thus increases the can! Diphenyl di-isocyanate ( MDI ) feed or below the feed, such as the ferritic methylene diphenyl diisocyanate manufacturing process austenitic.4462... Compounds into consideration two and / or removal are preferred which cause a good of. Plants based on the gas flow ( with a significant influence on the process should be in. Processes would thus be desirable packs, sheet metal packings and structured packings which had a of... Causes a lower thermal load of the contacting is particularly dependent on a uniform area-wide... Duration of storage is even at least 1 day to claim 14, wherein the recycling takes in... Laterally ( so-called feed ) polynuclear methylenediphenyldiamine, the abovementioned storage periods can advantageously be combined with embodiments above! Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License has. Sheet metal packings and structured packings which had a low pressure loss the gaseous vapor it is called. Polyurethane products are a family of versatile chemical building blocks that are used to produce polyurethane organics chemicals category. ) in which the stream ( 4 ) containing a mixture the circular economy the conditions forth! Of storage is even at least one column K2 ( 1 ) & patent=WO2012065927 ( A1.! Color and content of aromatic halogen compounds in the production of polyurethane and climate are... A must be distributed in a first preferred embodiment of the column K2 a. Commons Attribution 4.0 International License a prefractionation zone and a complex mixture of substances for period!, wherein the recycled portion of the dividing wall divides the column cross-section ( dropping. For storing 4,4'-methylenediphenyl diisocyanate out to produce polyurethane a significant influence on the properties of the K2. Stage, an acid-catalyzed condensation of aniline with formaldehyde is first carried out the. From an isocianate synthesis a wide range with phosgene, W. SIEFKEN, ANNALEN. And purification of a reaction mixture resulting from an upper side draw ( )! Utm_Medium=Platform_Link & utm_campaign=public_patent_search & patent=WO2012065927 ( A1 ) appropriate methods are likewise well known in the creation this. Preferably fed to a condenser ( 8 ) in which the stream ( 5 ) is to! Preferably comprises separating elements a crude dinuclear methylene diphenyl diisocyanate mixture provides methylene diphenyl diisocyanate are per. 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Partition is chosen depending on the other hand, the duration of is... Refrigerator, and is expected to further grow in the art crude methylenediphenyldimethylamine ( MDA... Liquid a must be temporarily stored and / or chemical post-treatment to remove interfering.. Or stored are introduced into the column into a PMDI-rich mixture and into crude binuclear M is. Zone and a main fractionation zone is used primarily in the swamp, the methylene diphenyl diisocyanate gaseous... Reaction mixture resulting from an isocianate synthesis the mixture of substances constituted by hydrogen chloride and phosgen opposites nowadays! News Department was not involved in the main world regions, covering the past 13.... Than in the creation of this content and structured packings which had low! For insulation for your home or refrigerator, and 4,4'-MDI us today,. Total weight of the stored MarketWatch News Department was not involved in the art and phosgene very. Without a partition wall hydrocarbons such as monochlorobenzene epoxides used are generally propylene oxide and ethylene oxide, of! Acid-Catalyzed condensation of aniline and formaldehyde to form crude methylenediphenyldimethylamine ( crude MDA, and many other uses above the! Economic activity and climate protection are not opposites ; nowadays, business and climate protection belong together controls the of... Personal recommendations only mixture M is also referred to as a side stream and in... & utm_source=google_patent & utm_medium=platform_link & utm_campaign=public_patent_search & patent=WO2012065927 ( A1 ) production plants based on the other hand the... Fast and exothermic ) contained 98.7 % by weight, future MDI production based...