Patents by Inventor Hartmut Knofel

Hartmut Knofel has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5684180
    Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and to the use thereof.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: November 4, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5679841
    Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and the use thereof.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: October 21, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5679840
    Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and their use.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: October 21, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5675035
    Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and to their use.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: October 7, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5672737
    Abstract: The invention relates to a process for the fractionation and purification of mixtures of aromatic polyamines and to the use thereof.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: September 30, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5663424
    Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and the use thereof.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: September 2, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5648519
    Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and to the use thereof.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: July 15, 1997
    Assignee: Bayer Aktiengesesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5648520
    Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and the use thereof.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: July 15, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 5359141
    Abstract: The invention relates to an improved process for the production of polynuclear aromatic polyamines by condensation of aniline with formaldehyde in the presence of water and acidic catalysts and working up of the reaction mixture by extraction with a hydrophobic solvent, the acid catalyst accumulating in the aqueous phase of the extraction step being reused.
    Type: Grant
    Filed: April 6, 1992
    Date of Patent: October 25, 1994
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Marcel Petinaux, Rudolf Uchdorf, Hans-Peter Schal
  • Patent number: 5196591
    Abstract: The invention relates to an improved process for the production of polynuclear aromatic polyamines by condensation of aniline with formaldehyde in the presence of water and acidic catalysts and working up of the reaction mixture by extraction with a hydrophobic solvent, the acid catalyst accumulating in the aqueous phase of the extraction step being reused.
    Type: Grant
    Filed: April 6, 1992
    Date of Patent: March 23, 1993
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Marcel Petinaux, Rudolf Uchdorf, Hans-Peter Schal
  • Patent number: 5043471
    Abstract: The present invention relates to a process for the preparation of a polyisocyanate comprising(a) thermally decomposing in a tube reactor a solution of an N-substituted carbamic acid ester corresponding to said polyisocyanate in a solvent used as decompositoin medium, wherein said solvent (i) is capable of dissolving the carbamic acid ester, (ii) is stable at the decomposition temperature and chemically inert towards the carbamic acid esters and the polyisocyanate product, (iii) can be distilled without decomposing under the conditions of decomposition of carbamic acid estes, and (iv) has at least one miscibility gap with an extracting agent used according to the extraction step (c), said solutions being carried along the internal wall of reactor;(b) separating the gaseous materials formed in the tube reactor by fractional condensation into a fraction I comprised mainly of the alcohol by-product and a fraction II comprised mainly of polyisocyanates, isocyanatourethanes, unreacted carbamic acid ester, and the s
    Type: Grant
    Filed: May 4, 1990
    Date of Patent: August 27, 1991
    Assignee: Bayer Aktiengesellschaft
    Inventors: Gunter Hammen, Hartmut Knofel, Wolfgang Friederichs
  • Patent number: 4924028
    Abstract: This invention relates to an improved process for the preparation of polynuclear aromatic polyamines in which the reaction product is prepared by condensing aniline with formaldehyde in the presence of water and acidic catalysts and is worked up by extraction with a hydrophobic solvent. The acid catalyst that accumulates in the aqueous phase during the extraction process is reused.
    Type: Grant
    Filed: April 6, 1989
    Date of Patent: May 8, 1990
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Marcel Petinaux, Rudolf Uchdorf
  • Patent number: 4914236
    Abstract: The present invention relates to an improved process for the preparation of multinuclear aromatic polyamines by the condensation of aniline with formaldehyde in the presence of water and acid catalysts and working up of the reaction mixture by extraction with a hydrophobic solvent. The acid catalyst obtained in the aqueous phase of extraction is reused.
    Type: Grant
    Filed: April 25, 1988
    Date of Patent: April 3, 1990
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Marcel Petinaux, Rudolf Uchdorf
  • Patent number: 4879408
    Abstract: Diisocyanates and isomer mixtures of diisocyanates corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, m and n are as defined herein are produced by phosgenating diamines and isomer mixtures of diamines corresponding to the formula ##STR2## in which R.sup.1, R.sup.2, m and n are as defined herein. These diisocyanates which are liquid at room temperature and highly compatible with polyols are particularly useful in the production of polyurethanes.
    Type: Grant
    Filed: April 7, 1987
    Date of Patent: November 7, 1989
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Stefan Penninger, Herbert Stutz
  • Patent number: 4879409
    Abstract: A diisocyanate corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein is prepared by phosgenating a diamine corresponding to the formula ##STR2## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein. The diisocyanate may contain C.sub.1 -C.sub.12 -monoalkyl-substituted methylene-bis-(cyclohexylisocyanate)isomers in an amount of up to 40 wt. %. These new diisocyanates which are liquid at room temperature and compatible with polyols are particularly useful in the production of polyurethanes.
    Type: Grant
    Filed: April 7, 1987
    Date of Patent: November 7, 1989
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Stefan Penninger, Herbert Stutz
  • Patent number: 4786751
    Abstract: Diisocyanates and isomeric mixtures of diisocyanates corresponding to the formula ##STR1## in which R.sub.1, R.sub.2, R.sub.3, m and n are as defined herein are made by phosgenating diamines corresponding to the formula ##STR2## in which R.sub.1, R.sub.2, R.sub.3, m and n are as defined herein at a temperature of from -20.degree. to 250.degree. C. These diisocyanates are particularly useful as starting materials for the production of polyurethanes by the isocyanate polyaddition process.
    Type: Grant
    Filed: November 12, 1985
    Date of Patent: November 22, 1988
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Stefan Penninger, Herbert Stutz
  • Patent number: 4761498
    Abstract: The instant invention is directed to diisocyanates based on diphenylmethane which may be methyl-substituted and which are characterized in particular by isocyanate groups in the 3,4'- and optionally in the 3,2'-position. The instant invention is also directed to a number of independent processes for their production and to their use as isocyanate component in the production of polyurethanes.
    Type: Grant
    Filed: March 20, 1987
    Date of Patent: August 2, 1988
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Gerhard Wegener
  • Patent number: 4720582
    Abstract: Diamines corresponding to the general formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 may be identical or different and represent hydrogen or straight- or branched-chain C.sub.1 -C.sub.12 alkyl groups, provided that two of the radicals,R.sup.1, R.sup.2 and R.sup.3, represent hydrogen, m and n each represent 0 or 1, provided that m+n=1; where m or n=0, the free valence is saturated by hydrogen, optionally in the form of isomeric mixtures, and optionally containing up to 35%, by weight, of the corresponding perhydrogenated diamines, and up to 10%, by weight, of the corresponding unhydrogenated aromatic diamines.Also, a process for preparing these diamines by catalytically-hydrogenating the corresponding aromatic diamines with 3 moles of hydrogen per mole of diamine, or catalytically-hydrogenating the corresponding dinitro compounds with 9 moles of hydrogen per mole of dinitro compound.
    Type: Grant
    Filed: August 15, 1983
    Date of Patent: January 19, 1988
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt, Stefan Penninger
  • Patent number: 4698424
    Abstract: The present invention relates to isocyanato-isocyanurates corresponding to the formula ##STR1## in which X.sub.1, X.sub.2 and X.sub.3 may be the same or different and represent radicals corresponding to the formula ##STR2## wherein R.sup.1 and R.sup.2 may be the same or different and represent hydrogen or C.sub.1 -C.sub.12 alkyl groups, and p is a whole or (on a statistical average) fractional number of from 1 to 5.The present invention also relates to a process for producing these isocyanato-isocyanurates and additionally relates to the use of the new isocyanato-isocyanurates, optionally blocked by blocking agents for isocyanate groups, as the isocyanate component in the produciton of isocyanate polyaddition products, preferably polyurethane lacquers.
    Type: Grant
    Filed: October 31, 1984
    Date of Patent: October 6, 1987
    Assignee: Bayer Aktiengesellschaft
    Inventors: Theodor Engbert, Hartmut Knofel, Gerhard Wegener
  • Patent number: 4692550
    Abstract: N-monosubstituted carbamic acid esters are thermally split on a continuous basis in a tube reactor. The carbamic acid ester which is flowed down or passed over the inner wall of a tube reactor is thermally split at a temperature of from 150.degree. to 450.degree. C. and under a pressure of from 0.001 to 20 bar into at least two fractions. One fraction is predominantly isocyanate and a second fraction is predominantly hydroxyl compound. These fractions may be separated by removing one as a gaseous fraction formed under the splitting conditions from the head of the reactor and collecting the second fraction as a liquid which accumulates at the base of the reactor. If both fractions are gaseous under the splitting conditions, they are both removed from the head of the reactor and subsequently separated by fractionating columns for example. This process is particularly advantageous in that isocyanate and hydroxyl fractions are obtained in high yield without using a solvent.
    Type: Grant
    Filed: April 15, 1983
    Date of Patent: September 8, 1987
    Assignee: Bayer Aktiengesellschaft
    Inventors: Theodor Engbert, Gunter Hammen, Hartmut Knofel, Klaus Konig