CA2142911A1 - Method of manufacturing a residue-free 2,4/2,6- diaminotoluene mixture - Google Patents
Method of manufacturing a residue-free 2,4/2,6- diaminotoluene mixtureInfo
- Publication number
- CA2142911A1 CA2142911A1 CA002142911A CA2142911A CA2142911A1 CA 2142911 A1 CA2142911 A1 CA 2142911A1 CA 002142911 A CA002142911 A CA 002142911A CA 2142911 A CA2142911 A CA 2142911A CA 2142911 A1 CA2142911 A1 CA 2142911A1
- Authority
- CA
- Canada
- Prior art keywords
- residue
- distillation
- boiling
- tda
- tolylenediamine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7614—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring
- C08G18/7621—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring being toluene diisocyanate including isomer mixtures
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/86—Separation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
- C07C209/32—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups
- C07C209/36—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups by reduction of nitro groups bound to carbon atoms of six-membered aromatic rings in presence of hydrogen-containing gases and a catalyst
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Processing Of Solid Wastes (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
The present invention relates to a process for the continuous separation of residue from raw m-diaminotoluene mixtures (m-TDA; 2,4/2,6-diaminotoluene mixture) for the preparation of residue-free 2,4/2,6-diaminotoluene mixtures (m-TDA), and use of the residue-free m-TDA mixtures.
Description
21i2911 -Le A 29 279-F.C.
Process for the preparation of residue-free 2,4/2,6-diaminotoluene mixture The present invention relates to a process for the continuous separation of residue from raw m-diaminotoluene mixtures (m-TDA; 2,4/2,6-diaminotoluene mixture) for the preparation of residue-free 2,4/2,6-diaminotoluene mixtures (m-TDA~, and use of the residue-free m-TDA mixtures.
When m-TDA is industrially produced on a large scale by dinitration of toluene followed by hydrogenation to the tolylenediamines, higher-boiling by-products, inter alia diphenylmethanes, diphenylamines, acridines and phenazines, naturally arise.
The m-tolylenediamine mixture produced from toluene by dinitration followed by hydrogenation contains between 0.3%
and 2 % of higher molecular weight incidental constituents, hereinafter designated TDA residue, depending on the process used for its preparation. Three processes are known for further processing the residue-containing m-TDA
mixture after the more volatile components - solvent and water - and the ortho-isomers (2,3- and 3,4-diaminotoluenes) have been separated by distillation.
1. The residue-containing m-TDA mixture is directly phosgenated to m-tolylene diisocyanate (TDI). The higher molecular weight compounds also phosgenated in the process are discharged as a TDI residue in the working-up process.
21~29il -Advantage: - a process step is saved Disadvantages: - the process can be applied only to liquid-phase phosgenation - residue in the m-TDA leads in the next process to increased formation of higher molecular weight components, at the expense of yield - difficulties in residue removal from the TDI process.
Process for the preparation of residue-free 2,4/2,6-diaminotoluene mixture The present invention relates to a process for the continuous separation of residue from raw m-diaminotoluene mixtures (m-TDA; 2,4/2,6-diaminotoluene mixture) for the preparation of residue-free 2,4/2,6-diaminotoluene mixtures (m-TDA~, and use of the residue-free m-TDA mixtures.
When m-TDA is industrially produced on a large scale by dinitration of toluene followed by hydrogenation to the tolylenediamines, higher-boiling by-products, inter alia diphenylmethanes, diphenylamines, acridines and phenazines, naturally arise.
The m-tolylenediamine mixture produced from toluene by dinitration followed by hydrogenation contains between 0.3%
and 2 % of higher molecular weight incidental constituents, hereinafter designated TDA residue, depending on the process used for its preparation. Three processes are known for further processing the residue-containing m-TDA
mixture after the more volatile components - solvent and water - and the ortho-isomers (2,3- and 3,4-diaminotoluenes) have been separated by distillation.
1. The residue-containing m-TDA mixture is directly phosgenated to m-tolylene diisocyanate (TDI). The higher molecular weight compounds also phosgenated in the process are discharged as a TDI residue in the working-up process.
21~29il -Advantage: - a process step is saved Disadvantages: - the process can be applied only to liquid-phase phosgenation - residue in the m-TDA leads in the next process to increased formation of higher molecular weight components, at the expense of yield - difficulties in residue removal from the TDI process.
2. The residue-containing m-TDA mixture is distilled out over a column in distillation boilers heated with steam at 30 bar. A proportion of m-TDA > 5% r~m~ins in the bottom to ensure that the bottom is fluid under these conditions (230 C).
Advantage: - the residue-free m-TDA can be utilised in gas phase phosgenation - and as a marketable product.
Disadvantages: - lower yield than in the process discussed under head 1, - disposal of the TDA residue mixture (highly viscous) by combustion, with loss of m-TDA.
Advantage: - the residue-free m-TDA can be utilised in gas phase phosgenation - and as a marketable product.
Disadvantages: - lower yield than in the process discussed under head 1, - disposal of the TDA residue mixture (highly viscous) by combustion, with loss of m-TDA.
3. Continuous residue separation by residual evaporation of the residue-containing m-TDA in thin-film evaporators and discharge of the residue having a m-TDA
content > 10% as "plasticiser".
Advantage: - the residue-free m-TDA can be utilised in gas phase phosgenation and as a~marketable product.
21~2911 Disadvantages: - lower yield than in the process discussed under head 1, - disposal of the TDA residue mixture (highly viscous) by combustion, with loss of m-TDA.
When the residue is separated by distillation in accordance with the processes under heads 2 and 3, the residue occurs as a highly viscous mass which - depending on the m-TDA
content of the residue - vitrifies at temperatures below 150 C,. The m-TDA which remains in the residue detracts from the process yield.
The object of the invention was therefore to provide a process which enables residue-free m-TDA to be prepared and separated completely from the raw m-TDA or the residue, without the disadvantages mentioned above.
This object was achieved by means of the process according to the invention.
The subject of the invention is a process for the preparation of residue-free m-tolylenediamine by nitrating toluene, hydrogenating the nitro compounds, separating the water and the solvent by distillation, and removing the ortho-isomers from the tolylenediamine mixture by distillation, followed by distillation of the remainder, which is characterised in that the distillation is performed such that a quantity of 2,4- and 2,6-tolylenediamine (m-tolylenediamine, m-TDA) is distilled from the remainder such that a bottom having a residue concentration of from 30 to 70 wt-% remains, the latter bottom is mixed with an auxiliary substance which is inert-to tolylenediamines and has a boiling point of > 290 C, in a quantity such as to adjust a residue concentration of from 28 to 50 wt-%, the latter bottom which is mixed with 21~12911 _...
an auxiliary substance undergoes a further single- or multi-stage distillation until a residual concentration of 2,4- and 2,6-tolylenediamine of from 1 to 5 wt-% is obtained in the bottom, and the remaining residual bottom, which is still liquid even at low temperatures, is discharged.
The advantage of the process according to the invention is that, without incurring heavy technical costs, virtually all the m-TDA can be obtained free of residue, and that moreover the r~m~;n;ng residue itself can be discharged at low temperatures (approx. 100 C) without difficulty.
One or more compounds from the group below are preferably utilised as auxiliary substances:
- distillation residues from ethylene glycol preparation (EDR) - distillation residues from propylene glycol preparation (PDR) - high-boiling polyethers based on ethylene oxide - high-boiling polyethers based on propylene oxide - high-boiling polyethers based on mixed polymers of ethylene oxide and propylene oxide - high-boiling polyethers based on polytetrahydrofuran - high-boiling polyethers based on mixed polymers of aromatic hydroxyl compounds - high-boiling polyethers based on cycloaliphatic oxo compounds - sugar, for example molasses - high-boiling alkyl aromatics.
The process according to the invention is preferably performed continuously. The raw m-TDA (tolylenediamine mixture after separation of the more volatile components (water, solvent) and of the ortho-isomers) normally -contains from 0.3 to 2 wt-% residue. In a first step a quantity of m-TDA (2,4/2,6-tolylenediamine) is distilled off such that the concentration of the residue is subsequently from 30 to 70 wt-%. This concentrated raw m-TDA is mixed with an auxiliary substance and undergoes asecond distillation. This is conducted preferably at temperatures of between 160 C and 260 C, particularly preferably between 190 and 220 C, and at pressures of between 2 and 100 mbar, particularly preferably between 5 and 40 mbar. The concentration of m-TDA in the bottom after distillation is preferably now only from 1 to 5 wt-%.
The bottom is discharged and preferably has a viscosity at 100 C of < 150 mPas.
The in~ention is explained in greater detail with the aid of the Example which follows.
21~2911 -Example 152.733 kg of raw m-TDA having a residue content of 1.5%
are fed continuously into a distillation column which is operated at 206 C and 5 mbar. A distillate of 148.649 kg m-TDA is obtained (yield calculated on m-TDA: 98.81%).
The residue concentrate leaving the distillation column (4,0842 kg; residue content: 56.1%) is mixed with 5.325 kg of residue from ethylene glycol distillation and is fed continuously into a second column which is operated at 206 C and 5 mbar. A distillate of 1,724 kg of m-TDA is obtained (yield calculated on m-TDA: 1.15%). The total m-TDA yield is 99.95%.
The residue leaving the column still contains 0.05% m-TDA
(calculated on total m-TDA) and has a viscosity at 80 C of 50 mPas.
content > 10% as "plasticiser".
Advantage: - the residue-free m-TDA can be utilised in gas phase phosgenation and as a~marketable product.
21~2911 Disadvantages: - lower yield than in the process discussed under head 1, - disposal of the TDA residue mixture (highly viscous) by combustion, with loss of m-TDA.
When the residue is separated by distillation in accordance with the processes under heads 2 and 3, the residue occurs as a highly viscous mass which - depending on the m-TDA
content of the residue - vitrifies at temperatures below 150 C,. The m-TDA which remains in the residue detracts from the process yield.
The object of the invention was therefore to provide a process which enables residue-free m-TDA to be prepared and separated completely from the raw m-TDA or the residue, without the disadvantages mentioned above.
This object was achieved by means of the process according to the invention.
The subject of the invention is a process for the preparation of residue-free m-tolylenediamine by nitrating toluene, hydrogenating the nitro compounds, separating the water and the solvent by distillation, and removing the ortho-isomers from the tolylenediamine mixture by distillation, followed by distillation of the remainder, which is characterised in that the distillation is performed such that a quantity of 2,4- and 2,6-tolylenediamine (m-tolylenediamine, m-TDA) is distilled from the remainder such that a bottom having a residue concentration of from 30 to 70 wt-% remains, the latter bottom is mixed with an auxiliary substance which is inert-to tolylenediamines and has a boiling point of > 290 C, in a quantity such as to adjust a residue concentration of from 28 to 50 wt-%, the latter bottom which is mixed with 21~12911 _...
an auxiliary substance undergoes a further single- or multi-stage distillation until a residual concentration of 2,4- and 2,6-tolylenediamine of from 1 to 5 wt-% is obtained in the bottom, and the remaining residual bottom, which is still liquid even at low temperatures, is discharged.
The advantage of the process according to the invention is that, without incurring heavy technical costs, virtually all the m-TDA can be obtained free of residue, and that moreover the r~m~;n;ng residue itself can be discharged at low temperatures (approx. 100 C) without difficulty.
One or more compounds from the group below are preferably utilised as auxiliary substances:
- distillation residues from ethylene glycol preparation (EDR) - distillation residues from propylene glycol preparation (PDR) - high-boiling polyethers based on ethylene oxide - high-boiling polyethers based on propylene oxide - high-boiling polyethers based on mixed polymers of ethylene oxide and propylene oxide - high-boiling polyethers based on polytetrahydrofuran - high-boiling polyethers based on mixed polymers of aromatic hydroxyl compounds - high-boiling polyethers based on cycloaliphatic oxo compounds - sugar, for example molasses - high-boiling alkyl aromatics.
The process according to the invention is preferably performed continuously. The raw m-TDA (tolylenediamine mixture after separation of the more volatile components (water, solvent) and of the ortho-isomers) normally -contains from 0.3 to 2 wt-% residue. In a first step a quantity of m-TDA (2,4/2,6-tolylenediamine) is distilled off such that the concentration of the residue is subsequently from 30 to 70 wt-%. This concentrated raw m-TDA is mixed with an auxiliary substance and undergoes asecond distillation. This is conducted preferably at temperatures of between 160 C and 260 C, particularly preferably between 190 and 220 C, and at pressures of between 2 and 100 mbar, particularly preferably between 5 and 40 mbar. The concentration of m-TDA in the bottom after distillation is preferably now only from 1 to 5 wt-%.
The bottom is discharged and preferably has a viscosity at 100 C of < 150 mPas.
The in~ention is explained in greater detail with the aid of the Example which follows.
21~2911 -Example 152.733 kg of raw m-TDA having a residue content of 1.5%
are fed continuously into a distillation column which is operated at 206 C and 5 mbar. A distillate of 148.649 kg m-TDA is obtained (yield calculated on m-TDA: 98.81%).
The residue concentrate leaving the distillation column (4,0842 kg; residue content: 56.1%) is mixed with 5.325 kg of residue from ethylene glycol distillation and is fed continuously into a second column which is operated at 206 C and 5 mbar. A distillate of 1,724 kg of m-TDA is obtained (yield calculated on m-TDA: 1.15%). The total m-TDA yield is 99.95%.
The residue leaving the column still contains 0.05% m-TDA
(calculated on total m-TDA) and has a viscosity at 80 C of 50 mPas.
Claims (6)
1. Process for the preparation of residue-free m-tolylenediamine by nitrating toluene, hydrogenating the nitro compounds, separating the water and solvent by distillation and removing the ortho-isomers from the residue-containing tolylenediamine mixture by distillation, followed by distillation of the remainder, characterised in that the distillation is performed such that a quantity of 2,4- and 2,6-tolylenediamine (m-tolylenediamine, m-TDA) is distilled from the remainder such that a bottom having a residue concentration of from 30 to 70 wt-% remains, the latter bottom is mixed with an auxiliary substance which is inert to tolylenediamines and has a boiling point of > 290 °C in a quantity such as to adjust a residue concentration of from 28 to 50 wt-%, the latter bottom which is mixed with an auxiliary substance undergoes a further single- or multi-stage distillation until a residual 2,4- and 2,6-tolylenediamine concentration of from 1 to 5 wt-% is obtained in the bottom, and the remaining residual bottom, which is still liquid even at low temperatues, is discharged.
2. Process according to Claim 1, characterised in that one or more compounds from the following group are utilised as auxiliary substance:
- distillation residues from ethylene glycol preparation (EDR) - distillation residues from propylene glycol preparation (PDR) - high-boiling polyethers based on ethylene oxide - high-boiling polyethers based on propylene oxide - high-boiling polyethers based on mixed polymers of ethylene oxide and propylene oxide - high-boiling polyethers based on polytetrahydrofuran - high-boiling polyethers based on mixed polymers of aromatic hydroxyl compounds - high-boiling polyethers based on cycloaliphatic oxo compounds - sugar, for example molasses - high-boiling alkyl aromatics.
- distillation residues from ethylene glycol preparation (EDR) - distillation residues from propylene glycol preparation (PDR) - high-boiling polyethers based on ethylene oxide - high-boiling polyethers based on propylene oxide - high-boiling polyethers based on mixed polymers of ethylene oxide and propylene oxide - high-boiling polyethers based on polytetrahydrofuran - high-boiling polyethers based on mixed polymers of aromatic hydroxyl compounds - high-boiling polyethers based on cycloaliphatic oxo compounds - sugar, for example molasses - high-boiling alkyl aromatics.
3. Process according to Claim 1, characterised in that the distillation of the remainder takes place in single- or multi-stage manner.
4. Process according to Claim 1, characterised in that the distillation is performed at temperatures of from 160 °C
to 260 °C, preferably at temperatures of from 190 °C to 220 °C, and at pressures of from 2 to 100 mbar, preferably from 5 to 40 mbar.
to 260 °C, preferably at temperatures of from 190 °C to 220 °C, and at pressures of from 2 to 100 mbar, preferably from 5 to 40 mbar.
5. Use of the residue-free m-tolylenediamines prepared according to Claims 1 to 4 for the preparation of the corresponding tolylene diisocyanate mixtures.
6. Use of the residue-free m-tolylenediamines prepared according to Claims 1 to 4 for the preparation of polyurethanes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4230098.3 | 1992-09-09 | ||
| DE4230098A DE4230098C1 (en) | 1992-09-09 | 1992-09-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2142911A1 true CA2142911A1 (en) | 1994-03-31 |
Family
ID=6467567
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002142911A Abandoned CA2142911A1 (en) | 1992-09-09 | 1993-08-30 | Method of manufacturing a residue-free 2,4/2,6- diaminotoluene mixture |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0659173B1 (en) |
| JP (1) | JPH08501106A (en) |
| KR (1) | KR950703513A (en) |
| CA (1) | CA2142911A1 (en) |
| DE (2) | DE4230098C1 (en) |
| ES (1) | ES2109511T3 (en) |
| MX (1) | MX9305506A (en) |
| TW (1) | TW261604B (en) |
| WO (1) | WO1994006752A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5849947A (en) * | 1995-08-04 | 1998-12-15 | Bayer Aktiengesellschaft | Process for the preparation of toluylene diisocyanate, specific mixtures of toluylene diamine and water, and the use of toluylene diamine and water mixtures to prepare toluylene diisocyanate |
| US9365503B2 (en) | 2008-12-19 | 2016-06-14 | Covestro Deutschland Ag | Process for the preparation of isocyanates in the gas phase |
| US11078151B2 (en) | 2017-01-27 | 2021-08-03 | Covestro Llc | Process for the preparation of stable toluene diamine residue/water blends, related compositions, and methods of using such blends as a fuel |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19608443C1 (en) * | 1996-03-05 | 1997-07-24 | Bayer Ag | Process for working up amine mixtures in the production of diaminotoluene with removal of the high boilers |
| FR2777560B1 (en) * | 1998-04-17 | 2000-06-09 | Rhodia Chimie Sa | PROCESS FOR THE PURIFICATION OF AROMATIC POLYAMINES |
| DE102004001456A1 (en) * | 2004-01-08 | 2005-08-11 | Basf Ag | Process for the distillative treatment of toluenediamine |
| DE102005032430A1 (en) * | 2005-07-12 | 2007-01-25 | Bayer Materialscience Ag | Process for the preparation of toluenediamine |
| US8030522B2 (en) * | 2006-06-07 | 2011-10-04 | Bayer Materialscience Llc | Process for the production of toluene diisocyanate |
-
1992
- 1992-09-09 DE DE4230098A patent/DE4230098C1/de not_active Expired - Fee Related
-
1993
- 1993-08-02 TW TW082106153A patent/TW261604B/zh active
- 1993-08-30 ES ES93919214T patent/ES2109511T3/en not_active Expired - Lifetime
- 1993-08-30 CA CA002142911A patent/CA2142911A1/en not_active Abandoned
- 1993-08-30 JP JP6507738A patent/JPH08501106A/en active Pending
- 1993-08-30 KR KR1019950700912A patent/KR950703513A/en not_active Application Discontinuation
- 1993-08-30 DE DE59307795T patent/DE59307795D1/en not_active Expired - Fee Related
- 1993-08-30 WO PCT/EP1993/002335 patent/WO1994006752A1/en active IP Right Grant
- 1993-08-30 EP EP93919214A patent/EP0659173B1/en not_active Expired - Lifetime
- 1993-09-08 MX MX9305506A patent/MX9305506A/en unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5849947A (en) * | 1995-08-04 | 1998-12-15 | Bayer Aktiengesellschaft | Process for the preparation of toluylene diisocyanate, specific mixtures of toluylene diamine and water, and the use of toluylene diamine and water mixtures to prepare toluylene diisocyanate |
| US9365503B2 (en) | 2008-12-19 | 2016-06-14 | Covestro Deutschland Ag | Process for the preparation of isocyanates in the gas phase |
| US11078151B2 (en) | 2017-01-27 | 2021-08-03 | Covestro Llc | Process for the preparation of stable toluene diamine residue/water blends, related compositions, and methods of using such blends as a fuel |
Also Published As
| Publication number | Publication date |
|---|---|
| TW261604B (en) | 1995-11-01 |
| JPH08501106A (en) | 1996-02-06 |
| WO1994006752A1 (en) | 1994-03-31 |
| DE59307795D1 (en) | 1998-01-15 |
| EP0659173B1 (en) | 1997-12-03 |
| KR950703513A (en) | 1995-09-20 |
| MX9305506A (en) | 1994-05-31 |
| EP0659173A1 (en) | 1995-06-28 |
| DE4230098C1 (en) | 1993-06-03 |
| ES2109511T3 (en) | 1998-01-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |