CA2100718A1 - Process for the preparation of isocyanates by the decomposition of n,n,n'-trisubstituted ureas - Google Patents
Process for the preparation of isocyanates by the decomposition of n,n,n'-trisubstituted ureasInfo
- Publication number
- CA2100718A1 CA2100718A1 CA002100718A CA2100718A CA2100718A1 CA 2100718 A1 CA2100718 A1 CA 2100718A1 CA 002100718 A CA002100718 A CA 002100718A CA 2100718 A CA2100718 A CA 2100718A CA 2100718 A1 CA2100718 A1 CA 2100718A1
- Authority
- CA
- Canada
- Prior art keywords
- isocyanate
- formula
- isocyanates
- ureas
- cyclic
- 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
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C263/00—Preparation of derivatives of isocyanic acid
- C07C263/06—Preparation of derivatives of isocyanic acid from or via ureas
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2601/00—Systems containing only non-condensed rings
- C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
- C07C2601/14—The ring being saturated
Abstract
Abstract A process for the preparation of isocyanates which is characterized in that N,N,N'-trisubstituted ureas of the formula I
in which R1, R2 and R3 are identical or different and are a linear, branched or cyclic (C1-C2,)-alkyl radical which is unsubstituted or substituted by (C1-C6)-alkoxy, option-ally substituted phenyl, halogen or other radicals which are inert under the reaction conditions used, or R2 and R3 together are a heterocyclic non- aromatic ring which can optionally contain further heteroatoms, are decomposed, in a diluent which is inert under the reaction conditions, at elevated temperature, to an isocyanate of high volatility of the formula R1NCO and to a secondary amine of low volatility of the formula R2R3NH, whose boiling point is above that of the isocyanate and above the reaction temperature used, after which the isocyanate is drawn off at the top by means of a stream of carrier gas.
in which R1, R2 and R3 are identical or different and are a linear, branched or cyclic (C1-C2,)-alkyl radical which is unsubstituted or substituted by (C1-C6)-alkoxy, option-ally substituted phenyl, halogen or other radicals which are inert under the reaction conditions used, or R2 and R3 together are a heterocyclic non- aromatic ring which can optionally contain further heteroatoms, are decomposed, in a diluent which is inert under the reaction conditions, at elevated temperature, to an isocyanate of high volatility of the formula R1NCO and to a secondary amine of low volatility of the formula R2R3NH, whose boiling point is above that of the isocyanate and above the reaction temperature used, after which the isocyanate is drawn off at the top by means of a stream of carrier gas.
Description
`~
Process for the preparation of isocyanates by the decom-position of N,N,N~-trisubstituted ureas ~ he invention relates to a process for the preparation of isocyanates by the decomposition of N,N,N~-trisubstituted ureas.
Isocyanates represent an economically Lmportantgroup of intermediates which are used inter alia in the plastics industry, in the production of lacquers and in the preparation of plant protection agents.
For this reason, there are also a large number of known processes for the preparation of isocyanates, although these have several disadvantages. Thus, for example, earlier processes use mainly phosgene or phosgene derivatives as starting materials, while more recent processes, which avoid the use of phosgene, only achieve poor yields of isocyanates.
A180, processes have already been described where the starting materials used are substituted ureas which are thermally decomposed.
In French patent 1,473,821, tri~ubstituted ureas ar~ decomposed to isocyanic acid esters and amines at temperatures below 200C in a solvent with a dielectric constant of less than 40. However, the isocyanate6 are only obtained in a yield of about 60%.
US patent 3,936,484 proposes a process for the thermal decomposition of disubstituted ureas, especially for the preparation of toluylene 2,4-diisocyanate.
Preferably, the amine formed is removed from the reaction mixture by mean~ of a stream of carrier qas, to which a further solvent can be added.
The disadvantages of this process, however, are that mainly only the amine foxmed can be drawn off at the top and the actual product remains at the bottom and then has to be isolated and purified, and that a good yield can only be achieved by the addition of a further solvent.
Surprisingly, a proces~ for the preparation of isocyanates has now been found in which the starting .:
, .
.. ~ . . , , . ~ -.-` 21~0718 materials used are particular N,N,N'-trisubstituted ureas, which does not use phosgene and which provides the desired isocyanates in a simple manner and in high yield and purity.
The invention accordingly relates to a process for the preparation of isocyanates which is characterized in that N,N,N~-trisubstituted ureas o. formula I:
\ N J ~ , " Rl in which R1, R2 and R3 are identical or different and are a linear, branched or cyclic (Cl-C2~)-alkyl radical which i~ unsubstituted or substituted by (Cl-C6)-alkoxy, option-ally sub~tituted phenyl, halogen or other radicals which are inert under the reaction conditions used, or R2 and R3 together are a heterocyclic non- aromatic ring which can optionally contain further heteroatoms, are decomposed, in a dLluent which is inert under the reaction conditions, at elevated temperature, to an isocyanate of high volatility of the formula R~NC0 and to a secondary amine of low volatility of the formula R2R3NH, whose boiling point is above that of the isocyanate and above the reaction temperature used, after which the isocyanate is drawn off at the top by means of a stream of carrier gas.
In principle, suitable starting compounds are any ~,N,N'-trisubatituted ureas which decompose under thermal stress to an isocyanate of high volatility and to a secondary amine of low volatility, whose boiling point is above that of the isocyanate and above the reaction temperature. Such compounds are those of formula I in which Rl, R2 and R3 are identical or different and are a linear, branched or cyclic ~Cl- C2,)-alkyl radical which is unsubstituted or substituted by (C1-C6)-alkoxy, optionally substituted phenyl, halogen or other radicals which are inert under the reaction conditions used, such -- 2~00718 . .
as, for instance, a methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, tert-butyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, cyclohexyl or benzyl radical.
Examples of (Cl-C6)-alkoxy radical~ are methoxy, ethoxy, propoxy, butoxy and hexyloxy. For example, the phenyl radical can be substituted inter alia by (Cl-C~)-alkyl, (Cl-C~)-alkoxy, halogen, amino or nitro. R2 and R3 can also together form a heterocyclic non-aromatic ring which can contain further heteroatoms, such as, for instance, pyrrolidine, piperidine, piperazine or morpholine.
Preferred starting compounds are compounds of formula I in which Rl is a linear, branched or cyclic (C2-C10)-alkyl radical or a benzyl radical and R2 and R3 are a linear, branched or cyclic (C~-C20)-alkyl radical or a benzyl radical.
Particularly preferred N,N,N'-trisubstituted ureas are therefore inter alia N,N-dioctyl-N~-ethylurea, N,N-dioctyl-N'-propylurea, N,N-dicyclohexyl-N'-propylurea, N,N-dioctyl-N'-isopropylurea, N,N-dibenzyl-N'-butylurea, N,N-dioctyl-N'-butylurea, N,N-dioctyl-N'-benzylurea and N,N-dioctyl-N'-cyclohexylurea.
The ureas can be prepared for example ~ia the N-alkylation of urea, as described in European Patent 0 471 983.
The decomposition can take place in a diluent which is inert under the reaction conditions. Suitable inert diluents are higher-boiling aliphatic or aromatic hydrocarbons such as, for instance, tetradecane, dodecane, hexadecane, octadecane, paraffin or mixtures thereof, although the ~mine formed by the decomposition of the urea can also be used as the diluent. The reaction temperature is between about 90 and 400-C, preferably 35 between 150 and 300-C and particularly preferably between 210 and 280-C, depending on the urea used. The isocyanates are isolated from the reaction mixture by means of a stream 'of inert gas, for instance by means of a stream of nitrogen or argon. The isocyanates are then either condensed in a cold trap or absorbed in a solvent.
Suitable solvents for the isocyanates are aliphatic or aromatic hydrocarbons which can optionally also be halogenated, such as, for instance, chloroform, methylene chloride, trichloroethylene and toluene, and ethers such as, for instance, tetrahydrofuran. The solvent, or part thereof, can already be incorporated as vapor with the stream of inert gas, or incorporated into the reaction mixture before decomposition begins.
If desired, the reaction can also be carried out under reduced or elevated pressure, the pressure being ad~usted to the desired value according to the chosen starting materials and the end products formed.
The reaction time is between 15 and 120 minutes, depending on the reaction temperature, the reaction pressure and the starting compounds. The secondary amine, which remains at the bottom during the decomposition, can be isolated from the bottom for example by distillation under reduced pressure and used as the starting compound for a variety of reactions. The desired isocyanates are obtained in high purity and in yields of up to 99.9%.
~a ple ls Ethyl isocyanate In a suitable apparatus comprising, in addition to a temperature-regulated reaction vessel, a device for introducing and, ideally, distributing the stream of inert ga~ in the reaction mixture, and a column for facilitating product separation (e.g. a metal-coated 30 cm Vigreux column was used), 5 g of N,N-dioctyl-N'-ethylurea were heated at about 250-C for 30 minutes in 50 g of hexadecane and 2.5 g of CHCl3.
During this time, the ethyl i~ocyanate formed was removed from the reaction mixture by means of a stream of nitrogen (ca. 2 l/h) and conden6ed as a CHC13 solution in a cold trap cooled with liquid nitrogen.
Yield: 97%:
.
r~ :
.. .
Example 2:
Propyl isocyanate In the apparatus described in Example 1, 5 g of N,N-dicyclohexyl-N'-propylurea were heated at about 250C
for 40 minutes in 50 g of hexadecane and the propyl isocyanate formed was removed from the reaction mixture by means of a stream of nitrogen and condensed in a cold trap cooled with liquid nitrogen.
Yield: 99.9%
The following compounds were prepared ~ .
analogously:
Product Educt Solvent 1 i-propyl isocyanate N,N-dioctyl-N~- hexadecane isopropylurea 15 2 butyl isocyanate N,N-dioctyl-N~- hexadecane butylurea : :
Process for the preparation of isocyanates by the decom-position of N,N,N~-trisubstituted ureas ~ he invention relates to a process for the preparation of isocyanates by the decomposition of N,N,N~-trisubstituted ureas.
Isocyanates represent an economically Lmportantgroup of intermediates which are used inter alia in the plastics industry, in the production of lacquers and in the preparation of plant protection agents.
For this reason, there are also a large number of known processes for the preparation of isocyanates, although these have several disadvantages. Thus, for example, earlier processes use mainly phosgene or phosgene derivatives as starting materials, while more recent processes, which avoid the use of phosgene, only achieve poor yields of isocyanates.
A180, processes have already been described where the starting materials used are substituted ureas which are thermally decomposed.
In French patent 1,473,821, tri~ubstituted ureas ar~ decomposed to isocyanic acid esters and amines at temperatures below 200C in a solvent with a dielectric constant of less than 40. However, the isocyanate6 are only obtained in a yield of about 60%.
US patent 3,936,484 proposes a process for the thermal decomposition of disubstituted ureas, especially for the preparation of toluylene 2,4-diisocyanate.
Preferably, the amine formed is removed from the reaction mixture by mean~ of a stream of carrier qas, to which a further solvent can be added.
The disadvantages of this process, however, are that mainly only the amine foxmed can be drawn off at the top and the actual product remains at the bottom and then has to be isolated and purified, and that a good yield can only be achieved by the addition of a further solvent.
Surprisingly, a proces~ for the preparation of isocyanates has now been found in which the starting .:
, .
.. ~ . . , , . ~ -.-` 21~0718 materials used are particular N,N,N'-trisubstituted ureas, which does not use phosgene and which provides the desired isocyanates in a simple manner and in high yield and purity.
The invention accordingly relates to a process for the preparation of isocyanates which is characterized in that N,N,N~-trisubstituted ureas o. formula I:
\ N J ~ , " Rl in which R1, R2 and R3 are identical or different and are a linear, branched or cyclic (Cl-C2~)-alkyl radical which i~ unsubstituted or substituted by (Cl-C6)-alkoxy, option-ally sub~tituted phenyl, halogen or other radicals which are inert under the reaction conditions used, or R2 and R3 together are a heterocyclic non- aromatic ring which can optionally contain further heteroatoms, are decomposed, in a dLluent which is inert under the reaction conditions, at elevated temperature, to an isocyanate of high volatility of the formula R~NC0 and to a secondary amine of low volatility of the formula R2R3NH, whose boiling point is above that of the isocyanate and above the reaction temperature used, after which the isocyanate is drawn off at the top by means of a stream of carrier gas.
In principle, suitable starting compounds are any ~,N,N'-trisubatituted ureas which decompose under thermal stress to an isocyanate of high volatility and to a secondary amine of low volatility, whose boiling point is above that of the isocyanate and above the reaction temperature. Such compounds are those of formula I in which Rl, R2 and R3 are identical or different and are a linear, branched or cyclic ~Cl- C2,)-alkyl radical which is unsubstituted or substituted by (C1-C6)-alkoxy, optionally substituted phenyl, halogen or other radicals which are inert under the reaction conditions used, such -- 2~00718 . .
as, for instance, a methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, tert-butyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, cyclohexyl or benzyl radical.
Examples of (Cl-C6)-alkoxy radical~ are methoxy, ethoxy, propoxy, butoxy and hexyloxy. For example, the phenyl radical can be substituted inter alia by (Cl-C~)-alkyl, (Cl-C~)-alkoxy, halogen, amino or nitro. R2 and R3 can also together form a heterocyclic non-aromatic ring which can contain further heteroatoms, such as, for instance, pyrrolidine, piperidine, piperazine or morpholine.
Preferred starting compounds are compounds of formula I in which Rl is a linear, branched or cyclic (C2-C10)-alkyl radical or a benzyl radical and R2 and R3 are a linear, branched or cyclic (C~-C20)-alkyl radical or a benzyl radical.
Particularly preferred N,N,N'-trisubstituted ureas are therefore inter alia N,N-dioctyl-N~-ethylurea, N,N-dioctyl-N'-propylurea, N,N-dicyclohexyl-N'-propylurea, N,N-dioctyl-N'-isopropylurea, N,N-dibenzyl-N'-butylurea, N,N-dioctyl-N'-butylurea, N,N-dioctyl-N'-benzylurea and N,N-dioctyl-N'-cyclohexylurea.
The ureas can be prepared for example ~ia the N-alkylation of urea, as described in European Patent 0 471 983.
The decomposition can take place in a diluent which is inert under the reaction conditions. Suitable inert diluents are higher-boiling aliphatic or aromatic hydrocarbons such as, for instance, tetradecane, dodecane, hexadecane, octadecane, paraffin or mixtures thereof, although the ~mine formed by the decomposition of the urea can also be used as the diluent. The reaction temperature is between about 90 and 400-C, preferably 35 between 150 and 300-C and particularly preferably between 210 and 280-C, depending on the urea used. The isocyanates are isolated from the reaction mixture by means of a stream 'of inert gas, for instance by means of a stream of nitrogen or argon. The isocyanates are then either condensed in a cold trap or absorbed in a solvent.
Suitable solvents for the isocyanates are aliphatic or aromatic hydrocarbons which can optionally also be halogenated, such as, for instance, chloroform, methylene chloride, trichloroethylene and toluene, and ethers such as, for instance, tetrahydrofuran. The solvent, or part thereof, can already be incorporated as vapor with the stream of inert gas, or incorporated into the reaction mixture before decomposition begins.
If desired, the reaction can also be carried out under reduced or elevated pressure, the pressure being ad~usted to the desired value according to the chosen starting materials and the end products formed.
The reaction time is between 15 and 120 minutes, depending on the reaction temperature, the reaction pressure and the starting compounds. The secondary amine, which remains at the bottom during the decomposition, can be isolated from the bottom for example by distillation under reduced pressure and used as the starting compound for a variety of reactions. The desired isocyanates are obtained in high purity and in yields of up to 99.9%.
~a ple ls Ethyl isocyanate In a suitable apparatus comprising, in addition to a temperature-regulated reaction vessel, a device for introducing and, ideally, distributing the stream of inert ga~ in the reaction mixture, and a column for facilitating product separation (e.g. a metal-coated 30 cm Vigreux column was used), 5 g of N,N-dioctyl-N'-ethylurea were heated at about 250-C for 30 minutes in 50 g of hexadecane and 2.5 g of CHCl3.
During this time, the ethyl i~ocyanate formed was removed from the reaction mixture by means of a stream of nitrogen (ca. 2 l/h) and conden6ed as a CHC13 solution in a cold trap cooled with liquid nitrogen.
Yield: 97%:
.
r~ :
.. .
Example 2:
Propyl isocyanate In the apparatus described in Example 1, 5 g of N,N-dicyclohexyl-N'-propylurea were heated at about 250C
for 40 minutes in 50 g of hexadecane and the propyl isocyanate formed was removed from the reaction mixture by means of a stream of nitrogen and condensed in a cold trap cooled with liquid nitrogen.
Yield: 99.9%
The following compounds were prepared ~ .
analogously:
Product Educt Solvent 1 i-propyl isocyanate N,N-dioctyl-N~- hexadecane isopropylurea 15 2 butyl isocyanate N,N-dioctyl-N~- hexadecane butylurea : :
3 paraffin octadecane 4 N,N-dibenzyl-N'- hexadecane butylurea tert-butyl isocyanate N,N-dioctyl-N~- hexadecane tert-butylurea 6 cyclohexyl isocyanate N,N-dioctyl-N'- hexadecane cyclohexylurea 25 7 benzyl isocyanate N,N-dioctyl-N'- hexadecane bensylurea ~ .
:
:
Claims (4)
1. A process for the preparation of isocyanates, characterized in that N,N,N'-trisubstituted ureas of the formula I
in which R1, R2 and R3 are identical or different and are a linear, branched or cyclic (C1-C24)-alkyl radical which is unsubstituted or substituted by (C1-C6)-alkoxy, option-ally substituted phenyl, halogen or other radicals which are inert under the reaction conditions used, or R2 and R3 together are a heterocyclic non- aromatic ring which can optionally contain further heteroatoms, are decomposed, in a diluent which is inert under the reaction conditions, at elevated temperature, to an isocyanate of high volatility of the formula R1NCO and to a secondary amine of low volatility of the formula R2R3NH, whose boiling point is above that of the isocyanate and above the reaction temperature used, after which the isocyanate is drawn off at the top by means of a stream of carrier gas.
in which R1, R2 and R3 are identical or different and are a linear, branched or cyclic (C1-C24)-alkyl radical which is unsubstituted or substituted by (C1-C6)-alkoxy, option-ally substituted phenyl, halogen or other radicals which are inert under the reaction conditions used, or R2 and R3 together are a heterocyclic non- aromatic ring which can optionally contain further heteroatoms, are decomposed, in a diluent which is inert under the reaction conditions, at elevated temperature, to an isocyanate of high volatility of the formula R1NCO and to a secondary amine of low volatility of the formula R2R3NH, whose boiling point is above that of the isocyanate and above the reaction temperature used, after which the isocyanate is drawn off at the top by means of a stream of carrier gas.
2. A process according to Claim 1, characterized in that, in the N,N,N'-trisubstituted ureas of formula I
used, R1 is a linear, branched or cyclic (C2-C10)- alkyl radical or a benzyl radical and R2 and R3 are a linear, branched or cyclic (C4-C20)-alkyl radical or a benzyl radical.
used, R1 is a linear, branched or cyclic (C2-C10)- alkyl radical or a benzyl radical and R2 and R3 are a linear, branched or cyclic (C4-C20)-alkyl radical or a benzyl radical.
3. A process according to Claim 1, characterized in that the reaction temperature is about 150 - 300°C, preferably 220 - 280°C.
4. A process according to Claim 1, characterized in that the ureas are decomposed under a reduced pressure of about 0.01 to 100 mbar.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ATA1631/92 | 1992-08-13 | ||
| AT0163192A AT398762B (en) | 1992-08-13 | 1992-08-13 | METHOD FOR PRODUCING ISOCYANATES BY THE DECOMPOSITION OF N, N, N'-TRISUBSTITUTED UREAS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2100718A1 true CA2100718A1 (en) | 1994-02-14 |
Family
ID=3517594
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002100718A Abandoned CA2100718A1 (en) | 1992-08-13 | 1993-07-16 | Process for the preparation of isocyanates by the decomposition of n,n,n'-trisubstituted ureas |
Country Status (20)
| Country | Link |
|---|---|
| EP (1) | EP0583637B1 (en) |
| JP (1) | JPH06157449A (en) |
| KR (1) | KR940003929A (en) |
| CN (1) | CN1085209A (en) |
| AT (2) | AT398762B (en) |
| AU (1) | AU4427093A (en) |
| CA (1) | CA2100718A1 (en) |
| CZ (1) | CZ166593A3 (en) |
| DE (1) | DE59305711D1 (en) |
| DK (1) | DK0583637T3 (en) |
| ES (1) | ES2097949T3 (en) |
| GR (1) | GR3022795T3 (en) |
| HU (1) | HU214218B (en) |
| MX (1) | MX9304898A (en) |
| NO (1) | NO932691L (en) |
| PL (1) | PL300037A1 (en) |
| SI (1) | SI9300427A (en) |
| SK (1) | SK71693A3 (en) |
| TW (1) | TW225517B (en) |
| ZA (1) | ZA935235B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9006480B2 (en) | 2010-04-14 | 2015-04-14 | 3M Innovative Properties Company | Process for producing isocyanates |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012176631A1 (en) * | 2011-06-24 | 2012-12-27 | 昭和電工株式会社 | Method for producing isocyanate compound containing ethylenically unsaturated group |
| KR101490202B1 (en) * | 2013-04-10 | 2015-02-05 | 광주과학기술원 | Microporous carbon dioxide adsorbents and method for manufacturing the same |
| CN108299294A (en) * | 2017-01-11 | 2018-07-20 | 江苏恒瑞医药股份有限公司 | A kind of pleasure is cut down for the preparation method of Buddhist nun's impurity |
| FR3068257B1 (en) * | 2017-06-29 | 2022-01-14 | Commissariat Energie Atomique | CARBAMIDES FOR THE SEPARATION OF URANIUM(VI) AND PLUTONIUM(IV) WITHOUT PLUTONIUM(IV) REDUCTION |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH228816A (en) * | 1940-11-19 | 1943-09-15 | Ig Farbenindustrie Ag | Process for the preparation of i-hexyl isocyanate. |
| FR1473821A (en) * | 1963-07-05 | 1967-03-24 | Carbochimique Et Inst Francais | New isocyanic ester manufacturing processes |
| US3936484A (en) * | 1974-09-25 | 1976-02-03 | Atlantic Richfield Company | Production of isocyanates from substituted ureas |
| US4141913A (en) * | 1978-01-23 | 1979-02-27 | American Carbonyl, Inc. | Method of generating lower alkyl and cycloalkyl isocyanates |
-
1992
- 1992-08-13 AT AT0163192A patent/AT398762B/en not_active IP Right Cessation
-
1993
- 1993-07-08 SK SK716-93A patent/SK71693A3/en unknown
- 1993-07-16 CA CA002100718A patent/CA2100718A1/en not_active Abandoned
- 1993-07-20 ZA ZA935235A patent/ZA935235B/en unknown
- 1993-07-21 DE DE59305711T patent/DE59305711D1/en not_active Expired - Fee Related
- 1993-07-21 AT AT93111624T patent/ATE150010T1/en not_active IP Right Cessation
- 1993-07-21 EP EP93111624A patent/EP0583637B1/en not_active Expired - Lifetime
- 1993-07-21 DK DK93111624.8T patent/DK0583637T3/en active
- 1993-07-21 ES ES93111624T patent/ES2097949T3/en not_active Expired - Lifetime
- 1993-07-23 TW TW082105877A patent/TW225517B/zh active
- 1993-07-26 NO NO932691A patent/NO932691L/en unknown
- 1993-07-28 AU AU44270/93A patent/AU4427093A/en not_active Abandoned
- 1993-08-11 PL PL93300037A patent/PL300037A1/en unknown
- 1993-08-12 MX MX9304898A patent/MX9304898A/en unknown
- 1993-08-12 HU HU9302338A patent/HU214218B/en not_active IP Right Cessation
- 1993-08-12 CN CN93116231A patent/CN1085209A/en active Pending
- 1993-08-12 KR KR1019930015595A patent/KR940003929A/en not_active Application Discontinuation
- 1993-08-12 JP JP5200824A patent/JPH06157449A/en not_active Withdrawn
- 1993-08-13 CZ CZ931665A patent/CZ166593A3/en unknown
- 1993-08-13 SI SI9300427A patent/SI9300427A/en unknown
-
1997
- 1997-03-13 GR GR960403090T patent/GR3022795T3/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9006480B2 (en) | 2010-04-14 | 2015-04-14 | 3M Innovative Properties Company | Process for producing isocyanates |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1085209A (en) | 1994-04-13 |
| NO932691L (en) | 1994-02-14 |
| ATA163192A (en) | 1994-06-15 |
| HU9302338D0 (en) | 1993-11-29 |
| ES2097949T3 (en) | 1997-04-16 |
| NO932691D0 (en) | 1993-07-26 |
| CZ166593A3 (en) | 1994-03-16 |
| ZA935235B (en) | 1994-03-02 |
| SI9300427A (en) | 1994-03-31 |
| GR3022795T3 (en) | 1997-06-30 |
| ATE150010T1 (en) | 1997-03-15 |
| SK71693A3 (en) | 1994-06-08 |
| AT398762B (en) | 1995-01-25 |
| DE59305711D1 (en) | 1997-04-17 |
| HUT64740A (en) | 1994-02-28 |
| PL300037A1 (en) | 1994-04-05 |
| TW225517B (en) | 1994-06-21 |
| HU214218B (en) | 1998-01-28 |
| KR940003929A (en) | 1994-03-14 |
| MX9304898A (en) | 1994-04-29 |
| AU4427093A (en) | 1994-02-17 |
| EP0583637B1 (en) | 1997-03-12 |
| JPH06157449A (en) | 1994-06-03 |
| EP0583637A1 (en) | 1994-02-23 |
| DK0583637T3 (en) | 1997-04-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |