Reactant Containing -nh-c(=o)-nh- Group (wherein Substitution May Be Made For Hydrogen Only) Patents (Class 560/344)
  • Patent number: 9056819
    Abstract: An object of the present invention is to provide an isocyanate production process, which is free of the various problems found in the prior art, and which uses a composition containing a carbamic acid ester and an aromatic hydroxy compound when producing isocyanate without using phosgene, as well as a carbamic acid ester composition for transferring or storing carbamic acid ester. The present invention discloses an isocyanate production process including specific steps and using a composition containing a carbamic acid ester and an aromatic hydroxy compound, as well as a composition for transfer or storage of carbamic acid ester comprising the carbamic acid ester and the specific aromatic hydroxy compound.
    Type: Grant
    Filed: March 26, 2008
    Date of Patent: June 16, 2015
    Assignee: Asahi Kasei Chemicals Corporation
    Inventors: Masaaki Shinohata, Nobuhisa Miyake
  • Patent number: 8871969
    Abstract: The invention provides a multistage process for continuously preparing organic polyisocyanates, preferably diisocyanates, more preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic polyamines with carbonic acid derivatives and alcohols into monomeric polyurethanes of low molecular mass, and the dissociation of said polyurethanes. The invention further provides an associated preparation process in which at certain reaction stages the polyisocyanates prepared and unutilizable residues are removed and reusable by-products and intermediates are recycled to preliminary stages.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: October 28, 2014
    Assignee: BASF SE
    Inventors: Torsten Mattke, Matthias Klötzer, Robert Baumann
  • Patent number: 8816125
    Abstract: The invention relates to a multi-stage process for the continuous, phosgene-free preparation of (cyclo)aliphatic diisocyanates that comprises the conversion of (cyclo)aliphatic diamines into the corresponding (cyclo)alkylene biscarbamates and the thermal cleaving of the latter into the (cyclo)alkylene diisocyanates and alcohol. The urea used in accordance with the invention and also the urea employed for the preparation of urea equivalents (e.g. alkyl carbonates, alkyl carbamates) as a possible precursor for the synthesis of the (cyclo)aliphatic biscarbamates is unconditioned.
    Type: Grant
    Filed: November 5, 2007
    Date of Patent: August 26, 2014
    Assignee: Evonik Degussa GmbH
    Inventors: Hans-Werner Michalczak, Stephan Kohlstruk, Manfred Kreczinski, Gerda Grund, Rainer Lomoelder
  • Patent number: 8748654
    Abstract: A method for producing tolylene diisocyanate includes: mixing a first diaminotoluene containing 2,4-diaminotoluene and 2,6-diaminotoluene at a first isomer ratio and a second diaminotoluene containing 2,4-diaminotoluene and/or 2,6-diaminotoluene at a second isomer ratio that is different from the first isomer ratio so as to prepare mixed diaminotoluene; producing tolylene dicarbamate by reaction of the mixed diaminotoluene, urea and/or N-unsubstituted carbamic acid ester and alcohol; and thermally decomposing the tolylene dicarbamate.
    Type: Grant
    Filed: April 6, 2012
    Date of Patent: June 10, 2014
    Assignee: Mitsui Chemicals, Inc.
    Inventors: Koji Takamatsu, Kazuhiro Kosumi, Takeshi Fukuda, Masaaki Sasaki
  • Patent number: 8546605
    Abstract: The invention provides a multistage process for continuously preparing organic, distillable polyisocyanates, preferably diisocyanates, more preferably aliphatic or cycloaliphatic diisocyanates, by reacting the corresponding organic polyamines with carbonic acid derivatives and alcohols to low molecular mass monomeric polyurethanes, and thermally cleaving said polyurethanes, in which at defined reaction stages the polyisocyanates prepared and unusable residues are separated off, and reusable by products and intermediates are recycled to upstream stages.
    Type: Grant
    Filed: September 5, 2006
    Date of Patent: October 1, 2013
    Assignee: BASF Aktiengesellschaft
    Inventors: Matthias Kloetzer, Eckhard Stroefer, Volker Krase, Andreas Schmidt, Peter Scherbel
  • Patent number: 8536370
    Abstract: Low chlorine, multi-staged method for producing cycloaliphatic diisocyanates. The invention relates to a multi-staged method for the continuous low-chlorine production of cycloaliphatic diisocyanates, comprising the synthesis of diaminodipheynl alkanes, the hydration thereof into the corresponding cycloaliphatic diamines and the subsequent conversion of cycloaliphatic diamines to the corresponding cycloalkylene biscarbamates and the thermal cleaving of the latter into the cycloaliphatic diisocyanates and alcohol.
    Type: Grant
    Filed: May 18, 2009
    Date of Patent: September 17, 2013
    Assignee: Evonik Degussa GmbH
    Inventors: Gerda Grund, Manfred Kreczinski, Stephan Kohlstruk, Christian Lettmann
  • Publication number: 20130006013
    Abstract: The invention provides a multistage process for continuously preparing organic polyisocyanates, preferably diisocyanates, more preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic polyamines with carbonic acid derivatives and alcohols into monomeric polyurethanes of low molecular mass, and the dissociation of said polyurethanes. The invention further provides an associated preparation process in which at certain reaction stages the polyisocyanates prepared and unutilizable residues are removed and reusable by-products and intermediates are recycled to preliminary stages.
    Type: Application
    Filed: May 30, 2012
    Publication date: January 3, 2013
    Applicant: BASF SE
    Inventors: Torsten Mattke, Matthias Klötzer, Robert Baumann
  • Publication number: 20120172621
    Abstract: The invention relates to a multistage process for the continuous preparation of organic, distillable polyisocyanates, preferably diisocyanates, particularly preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic polyamines with carbonic acid derivatives and alcohols to form low molecular weight monomeric polyurethanes and thermal dissociation of the latter, in which the polyisocyanates produced and unusable residues are separated off at particular stages of the reaction and reusable by-products and intermediates are recirculated to preceding stages.
    Type: Application
    Filed: September 9, 2010
    Publication date: July 5, 2012
    Applicant: BASF SE
    Inventors: Torsten Mattke, Matthias Kloetzer, Eckhard Stroefer, Bernhard Geissler, Peter Zehner
  • Patent number: 8193385
    Abstract: The invention relates to a multistage process for the continuous preparation of organic, distillable isocyanates, preferably diisocyanates, particularly preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic amines with urea and alcohols to liberate ammonia and form low molecular weight monomeric urethanes and thermal dissociation of the latter, in which by-products formed are at least partly utilized.
    Type: Grant
    Filed: August 8, 2007
    Date of Patent: June 5, 2012
    Assignee: BASF SE
    Inventors: Matthias Kloetzer, Heinrich-Josef Blankertz, Gunter Georgi, Eckhard Stroefer, Volker Krase, Gerhard Schulz, Andreas Warzecha
  • Publication number: 20100113823
    Abstract: An object of the present invention is to provide an isocyanate production process, which is free of the various problems found in the prior art, and which uses a composition containing a carbamic acid ester and an aromatic hydroxy compound when producing isocyanate without using phosgene, as well as a carbamic acid ester composition for transferring or storing carbamic acid ester. The present invention discloses an isocyanate production process including specific steps and using a composition containing a carbamic acid ester and an aromatic hydroxy compound, as well as a composition for transfer or storage of carbamic acid ester comprising the carbamic acid ester and the specific aromatic hydroxy compound.
    Type: Application
    Filed: March 26, 2008
    Publication date: May 6, 2010
    Inventors: Masaaki Shinohata, Nobuhisa Miyake
  • Publication number: 20100036154
    Abstract: The invention relates to a multi-stage process for the continuous, phosgene-free preparation of (cyclo)aliphatic diisocyanates that comprises the conversion of (cyclo)aliphatic diamines into the corresponding (cyclo)alkylene biscarbamates and the thermal cleaving of the latter into the (cyclo)alkylene diisocyanates and alcohol. The urea used in accordance with the invention and also the urea employed for the preparation of urea equivalents (e.g. alkyl carbonates, alkyl carbamates) as a possible precursor for the synthesis of the (cyclo)aliphatic biscarbamates is unconditioned.
    Type: Application
    Filed: November 5, 2007
    Publication date: February 11, 2010
    Applicant: EVONIK DEGUSSA GmbH
    Inventors: Hans-Werner Michalczak, Stephan Kohlstruk, Manfred Kreczinski, Gerda Grund, Rainer Lomoelder
  • Publication number: 20090275775
    Abstract: The invention relates to a multistage process for the continuous preparation of organic, distillable isocyanates, preferably diisocyanates, particularly preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic amines with urea and alcohols to liberate ammonia and form low molecular weight monomeric urethanes and thermal dissociation of the latter, in which by-products formed are at least partly utilized.
    Type: Application
    Filed: August 8, 2007
    Publication date: November 5, 2009
    Applicant: BASF SE
    Inventors: Matthias Kloetzer, Heinrich-Josef Blankertz, Gunter Georgi, Eckhard Stroefer, Volker Krase, Gerhard Schulz, Warzecha Andreas
  • Patent number: 7557242
    Abstract: Cycloaliphatic diisocyanates can be prepared continuously and phosgene-free by reacting at least one cycloaliphatic diamine with at least one carbonic acid derivative and at least one alcohol to give a cycloaliphatic diurethane; freeing the cycloaliphatic diurethane of a low boiler, a medium boiler and mixtures thereof; thermally cleaving the cycloaliphatic diurethane in a cleavage apparatus to give a cycloaliphatic diisocyanate and a cleavage residue; continuously discharging a portion of the cleavage residue from the cleavage apparatus; removing the high boiler components from the discharge to obtain a purified discharge; reurethanizing the purified discharge with alcohol to obtain a reurethanized discharge; and recycling the reurethanized discharge into the process.
    Type: Grant
    Filed: April 7, 2005
    Date of Patent: July 7, 2009
    Assignee: Degussa AG
    Inventors: Stephan Kohlstruk, Manfred Kreczinski, Hans-Werner Michalczak
  • Publication number: 20080249332
    Abstract: The invention provides a multistage process for continuously preparing organic, distillable polyisocyanates, preferably diisocyanates, more preferably aliphatic or cycloaliphatic diisocyanates, by reacting the corresponding organic polyamines with carbonic acid derivatives and alcohols to low molecular mass monomeric polyurethanes, and thermally cleaving said polyurethanes, in which at defined reaction stages the polyisocyanates prepared and unusable residues are separated off, and reusable by products and intermediates are recycled to upstream stages.
    Type: Application
    Filed: September 5, 2006
    Publication date: October 9, 2008
    Inventors: Matthias Klotzer, Eckhard Stroefer, Volker Krase, Andreas Schmidt, Peter Scherbel
  • Patent number: 6949672
    Abstract: The present invention relates to a process for preparing arylsulfonyl isocyanates by reacting an arylsulfonamide with phosgene in the presence of a catalytically effective amount of an alkyl isocyanate.
    Type: Grant
    Filed: October 10, 2002
    Date of Patent: September 27, 2005
    Assignee: BASF Aktiengesellschaft
    Inventors: Horst Mayer, Dieter Golsch
  • Patent number: 6664415
    Abstract: The present invention relates to a process for preparing a low boiling monoisocyanate having a boiling point of between 70 and 320° C. at standard pressure by reacting A) a high boiling isocyanate compound having a boiling point of at least 180° C. at standard pressure and an HC content of at least 50 ppm with B) a monoamine having a primary amino group, at a maximum reaction temperature of 180° C. and a molar ratio of isocyanate groups to amino groups of at least 4:1 to form a compound containing a biuret/urea group, simultaneously thermally decomposing this compound in situ to form a monoisocyanate corresponding to monoamine B) and removing the monoisocyanate by distillation, optionally under vacuum.
    Type: Grant
    Filed: April 30, 2001
    Date of Patent: December 16, 2003
    Assignee: Bayer Aktiengesellschaft
    Inventors: Martin Brahm, Lutz Schmalstieg, Ulrich Geron, Hans-Günter Behr, Jörg Morawski
  • Patent number: 6369268
    Abstract: Described are diester amine adducts of formula (1) wherein R1, R2, R3, R4 are each independently of one another C4-C22alkyl; C2-C22alkenyl; or C5-C7cycloalkyl; X1 and X2 are each independently of the other hydrogen, C1-C4alkyl; C2-C4hydroxyalkyl or C2-C4hydroxyhaloalkyl; Y is a radical of formula (1b); A1 is C2-C3alkylene or 2-hydroxy-n-propylene; X3 is hydrogen; C1-C4alkyl, C2-C4hydroxyalkyl; or C2-C4hydroxyhaloalkyl; (A) is an asymmetrical carbon atom in the R- or S-configuration, wherein, if C1=R, C2=R; C1=S, C2=S; and C1=R; C2=S; m1 is 1 or 2; and n is an integer from 1 to 4; p is 0 or 1; which adducts may be in the form of free bases or ammonium salts. Said compounds are precursors of compounds having good complex-forming properties and are thus able to effectively bind heavy metal ions such as iron, zinc, magnesium or copper ions and to prevent metal-initiated oxidations after enzymatic or chemical cleavage.
    Type: Grant
    Filed: May 1, 2000
    Date of Patent: April 9, 2002
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: Thomas Ehlis, Peter Frankhauser, Dietmar Hüglin
  • Patent number: 6093817
    Abstract: A reduced-color isocyanurate-functional polyisocyanate is prepared by partially trimerizing 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) having a low total chlorine content of less than 80 mg/kg in the presence of a catalyst, thereby resulting in a product isocyanurate-functional polyisocyanate having a content of free NCO groups of between 10 and 22% and a residual monomer content of less than 0.7%.
    Type: Grant
    Filed: December 29, 1998
    Date of Patent: July 25, 2000
    Assignee: Huels Aktiengesellschaft
    Inventors: Stephan Kohlstruk, Jansen Volker, Rainer Lomoelder
  • Patent number: 5633336
    Abstract: Low-viscosity (cyclo)-aliphatic polyamines containing urea groups and having more than two amino groups may be prepared by reacting (cyclo)aliphatic diamines with polyisocyanates containing isocyanurate groups or biuret groups. Such polyamines are useful as components in PUR reaction finishes and coating and adhesive compositions.
    Type: Grant
    Filed: November 6, 1995
    Date of Patent: May 27, 1997
    Assignee: Huels Aktiengesellschaft
    Inventors: Rainer Gras, Elmar Wolf
  • Patent number: 5386053
    Abstract: A multistep process for the continuous preparation of organic polyisocyanates, preferably aliphatic or cycloaliphatic diisocyanates, by reacting the corresponding organic polyamines with carbonic acid derivatives and alcohols to give monomeric polyurethanes and pyrolyzing the latter involves separating the resultant polyisocyanates and worthless residues in certain reaction steps and recycling the reusable by-products into earlier steps.
    Type: Grant
    Filed: March 8, 1993
    Date of Patent: January 31, 1995
    Assignee: BASF Aktiengesellschaft
    Inventors: Andreas Otterbach, Hans V. Schwarz, Franz Merger, Wolfgang Schwarz, Eckhardt Brandt, Peter Magnussen, Otto Mattner
  • Patent number: 5360931
    Abstract: A continuous multistage process for the preparation of (cyclo)aliphatic diisocyanates comprising a) condensing urea with a (cyclo)aliphatic diamine in the presence of an alcohol solvent to make a (cyclo)alkylenebisurea in a distillation reactor; b) reacting the crude (cyclo)alkylenebisurea with alcohol in a pressurized distillation reactor to make (cyclo)biscarbamate; c) removing the ammonia formed in the pressurized distillation reactor; d) cleaving the (cyclo)biscarbamate in the presence of a catalyst in a combined cleavage and rectifying column to make crude (cyclo)alkylene diisocyanate; e) reacting a diverted portion of the cleavage products with the alcohol to form a recycling mixture; f) and distilling the crude (cyclo)alkylene diisocyanate formed in step d.
    Type: Grant
    Filed: April 2, 1993
    Date of Patent: November 1, 1994
    Assignee: Huels Aktiengesellschaft
    Inventors: Gerd Bohmholdt, Wilhelm Heitmann, Peter Kirchner, Hans-Werner Michalczak
  • Patent number: 5360601
    Abstract: A process for the preparation of isocyanic acid, characterized in that N,N-disubstituted ureas are decomposed at elevated temperature to a secondary amine of lower volatility and to isocyanic acid, which is drawn off at the top.
    Type: Grant
    Filed: August 13, 1993
    Date of Patent: November 1, 1994
    Assignee: Chemie Linz Gesellschaft m.b.H.
    Inventors: Kurt A. Hackl, Martin Mullner, Erich Schulz, Gerhard Stern, Heinz Falk
  • Patent number: 5241118
    Abstract: A process for preparing trisubstituted ureas is disclosed. A nitroarene is reacted with carbon monoxide and a secondary amine in the presence of a Group VIII transition metal catalyst and optionally one or more promoters selected from primary amines, halide ion-containing compounds, and chelating phosphorus and nitrogen compounds.
    Type: Grant
    Filed: November 22, 1991
    Date of Patent: August 31, 1993
    Assignee: Arco Chemical Technology, L.P.
    Inventors: Robert J. Saxton, Wilfred P. Shum, Edward T. Shawl, Haven S. Kesling, Jr., John G. Zajacek
  • Patent number: 5096994
    Abstract: The present invention relates to polyisocyanates which contain ester groups and havea) a content of aliphatically bound isocyanate groups of 18 to 33% by weight,b) an average NCO functionality of 4.1 to 10, preferably from 4.5 to 10, andc) a viscosity of 200 to 2,5000 mPa.s at 22.degree. C.The present invention also relates to preferred polyisocyanates which contain ester groups and havea) a content of aliphatically bound isocyanate groups of 20 to 33% by weight,b) an average NCO functionality of 5 to 8 andc) a viscosity of 500 to 1,000 mPa.s at 22.degree. C.The present invention further relates to a process for the preparation of these preferred polyisocyanates by reacting isocyanatocarboxylic acid chlorides with O-silylated, polyhydric alcohols at a temperature of about 50.degree. to 150.degree. C. Finally, the present invention relates to the use of the polyisocyanates as the isocyanate component for two-component polyurethane coating compositions.
    Type: Grant
    Filed: August 2, 1990
    Date of Patent: March 17, 1992
    Assignee: Bayer Aktiengesellschaft
    Inventors: Lutz Schmalstieg, Josef Pedain, Klaus Nachtkamp, Lothar Kahl, Manfred Schonfelder
  • Patent number: 5087739
    Abstract: A circulation process for the production of (cyclo)aliphatic diisocyanates, in which the biscarbamate is produced from diamines, by-products from the thermal cracking, urea, and alcohol in the presence of N-unsubstituted carbamates and dialkyl carbonates, and with separation of NH.sub.3 ; the subsequent cracking of the biscarbamate is carried out in the liquid phase without solvent; the diisocyanate and alcohol are condensed; the diisocyanate is subjected to a purifying distillation; and a portion of the cracking reaction mixture is discharged with the by-products formed and recycled to the biscarbamate production step after prior reaction with the crude alcohol formed, effectively utilizes the by-products formed in the cracking step and is an industrially practical and economical process.
    Type: Grant
    Filed: May 28, 1991
    Date of Patent: February 11, 1992
    Assignee: Huels Aktiengesellschaft
    Inventors: Gerd Bohmholdt, Josef Disteldorf, Peter Kirchner, Hans-Werner Michalczak
  • Patent number: 5039801
    Abstract: The invention provides an improved method for obtaining optically active amines, carbamates, and isocyanates by thermal fragmentation of optically active ureas through refluxing the ureas in C.sub.3 -C.sub.7 alcohol solution with or without catalytic amounts of alkali metal.
    Type: Grant
    Filed: August 28, 1987
    Date of Patent: August 13, 1991
    Assignee: The United States of America as represented by the Department of Health & Human Services
    Inventors: Arnold Brossi, Bernhard Schonenberger
  • Patent number: 4978779
    Abstract: An improved process is provided for the preparation of methylene diphenylene diisocyanates (MDI) and polymethylene polyphenylene poly (isocyanates) (PMDI) by the thermal decomposition of a methylene diphenylene bis (dialkylurea) or a polymethylene polyphenylene poly (alkylurea) in a solvent in the presence of an organic sulfonic acid or sulfonated aromatic ion exchange resin as a promoter for conversion of the urea groups to the corresponding isocyanate.
    Type: Grant
    Filed: March 9, 1989
    Date of Patent: December 18, 1990
    Assignee: Arco Chemical Technology, Inc.
    Inventors: Edward T. Shawl, Haven S. Kesling, Jr., Frank J. Liotta, Jr.
  • Patent number: 4883908
    Abstract: An improved process is provided for the preparation of aromatic mono- and poly-isocyanates by the thermal decomposition of an aromatic bis dialkyl urea in solvent in the presence of an organic sulfonic acid or sulfonated aromatic ion exchange resin as a promoter for conversion of the urea groups to isocyanates.
    Type: Grant
    Filed: February 2, 1989
    Date of Patent: November 28, 1989
    Assignee: Arco Chemical Technology, Inc.
    Inventors: Edward T. Shawl, Haven S. Kesling, Jr., Frank J. Liotta, Jr.
  • Patent number: 4879410
    Abstract: A process is disclosed for the preparation of aralkyl mono- and diurethanes or ureas by carbamylmethylation, or acid-catalyzed addition at a temperature of 40.degree. C. to about 100.degree. C. of formaldehyde and esters of carbamic acid to aromatic hydrocarbons. Aralkyl carbamates and ureas formed by this process can be cracked directly to produce aralkyl diisocyanates, or hydrogenated and then cracked to produce aliphatic diisocyanates, or reacted directly with polyols to produce polyurethanes by functioning as blocked isocyanates.
    Type: Grant
    Filed: November 3, 1986
    Date of Patent: November 7, 1989
    Assignee: American Cyanamid Company
    Inventors: Balwant Singh, Laurence W. Chang, William A. Henderson, Jr.
  • Patent number: 4873364
    Abstract: An improved process is provided for the preparation of methylene diphenylene diisocyanates (MDI) and polymethylene polyphenylene poly (diisocyanates) by the thermal decomposition of a methylene diphenylene bis (dialkylurea) or a polymethylene polyphenylene poly (dialkylurea) in a solvent in the presence of a tertiary amine hydrohalide, such as pyridine hydrochloride, as a promoter for conversion of the urea groups to the corresponding isocyanate.
    Type: Grant
    Filed: December 9, 1988
    Date of Patent: October 10, 1989
    Assignee: Arco Chemical Technology, Inc.
    Inventors: Edward T. Shawl, Haven S. Kesling, Jr.
  • Patent number: 4871871
    Abstract: An improved process is provided for the preparation of aromatic mono- and poly- isocyanates by the thermal decomposition of an aromatic bis dialkyl urea in solvent in the presence of a tertiary amine hydrohalide, such as pyridine hydrochloride, as a promoter for conversion of the urea groups to isocyanates.
    Type: Grant
    Filed: November 3, 1988
    Date of Patent: October 3, 1989
    Assignee: Arco Chemical Technology, Inc.
    Inventors: Edward T. Shawl, Haven S. Kesling, Jr.
  • Patent number: 4613466
    Abstract: Hexamethylene 1,6-diisocyanate and/or isomeric aliphatic diisocyanates where alkylene is of 6 carbon atoms, preferably 2-methylpentamethylene 1,5-diisocyanate and/or 2-ethyltetramethylene 1,4-diisocyanate, are prepared by a process wherein the corresponding dialkylurethanes are vaporized, without decomposition, at from 220.degree. to 300.degree. C., advantageously under reduced pressure, the dialkylurethane vapors are subjected to thermal cleavage under reduced pressure, preferably from 0.1 to 200 mbar, and at above 300.degree. C., preferably from 310.degree. to 480.degree. C. The cleavage products are fractionally condensed with the product obtained in the first condensation stage consisting predominantly of the diisocyanates, while that obtained in the second condensation stage is the alcohol.
    Type: Grant
    Filed: July 15, 1985
    Date of Patent: September 23, 1986
    Assignee: BASF Aktiengesellschaft
    Inventors: Franz Merger, Gerhard Nestler, Friedrich Towae, Hans Hellbach
  • Patent number: 4596679
    Abstract: This invention discloses a non-phosgene process for the preparation of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate by the reaction of the precursor diamine with urea and an aliphatic alcohol in the presence of a dialkyl carbonate and an alkyl carbonate. The intermediate diurethane is separated from starting materials and by-products and thermally cleaved to alcohol and diisocyanate which are separated by fractional condensation of the products from the vapor state. This process gives high yields of the desired diisocyanate and lends itself particularly to continuous processing.
    Type: Grant
    Filed: April 13, 1984
    Date of Patent: June 24, 1986
    Assignee: BASF Aktiengesellschaft
    Inventors: Hans Hellbach, Franz Merger, Friedrich Towae