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: 4675437
    Abstract: Cycloaliphatic triisocyanates or isomer mixtures of such triisocyanates corresponding to the formula ##STR1## in which R represents hydrogen or a C.sub.1 -C.sub.4 alkyl group are produced by phosgenating the corresponding cycloaliphatic triamines or isomer mixtures of such triamines or a salt thereof.These triisocyanates are useful in the production of polyisocyanate addition products, particularly polyurethane coatings and lacquers.
    Type: Grant
    Filed: April 29, 1985
    Date of Patent: June 23, 1987
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Stefan Penninger, Michael Brockelt, Gunter Hammen, Herbert Stutz
  • Patent number: 4613687
    Abstract: A polyisocyanate or mixture of polyisocyanates in which the main component(s) correspond to the formula: ##STR1## in which R.sub.1, R.sub.2, and R.sub.3 each represent hydrogen or a saturated alkyl group containing from 1 to 12 carbon atoms, provided that at least two of these radicals represent hydrogen; andm, n, o and p each represent 0 or 1, provided that when m, n, o and/or p represent 0, the free valency is taken up by a hydrogen atom and that the sum of m+n+o+p is greater than 1 on a statistical average.Such polyisocyanate or mixture of polyisocyanates may be produced by first reacting a 4-nitrobenzyl halide, a 3-nitrobenzyl halide, a benzyl halide, a benzyl alcohol or a nitrobenzyl chloride isomer mixture with nitrobenzene, an alkyl-substituted nitrobenzene, an alkyl benzene or benzene in the presence of a Friedel-Crafts or an acid catalyst.
    Type: Grant
    Filed: August 17, 1981
    Date of Patent: September 23, 1986
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 4603189
    Abstract: Triisocyanates and isomeric mixtures of triisocyanates corresponding to the formula ##STR1## in which R represents hydrogen or an alkyl group having from 1 to 4 carbon atoms are made by phosgenating the corresponding triamine. These triisocyanates are particularly useful in the production of polyurethanes, especially polyurethane lacquer coats.
    Type: Grant
    Filed: April 29, 1985
    Date of Patent: July 29, 1986
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Stefan Penninger, Michael Brockelt, Gunter Hammen, Herbert Stutz
  • Patent number: 4593117
    Abstract: Low molecular weight N- and O-substituted diurethanes and/or polyurethanes are prepared by reacting a diamine and/or polyamine containing a primary amino group with an N-aryl-0-alkyl urethane in the presence of at least one high boiling alcohol. This reaction may be carried out at a temperature of from 180.degree. to 350.degree. C. and a pressure of approximately 0.1 to 1,500 mbar. The arylamine corresponding to the N-ary-0-alkyl urethane which forms during this reaction is continuously removed from the reaction mixture.
    Type: Grant
    Filed: December 5, 1984
    Date of Patent: June 3, 1986
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Stefan Penninger, Gunther Hammen, Peter Heitkamper
  • Patent number: 4587058
    Abstract: A diisocyanate corresponding to the general formula: ##STR1## in which R.sub.1, R.sub.2 and R.sub.3 represent hydrogen or a C.sub.2 -C.sub.12 alkyl group provided that two of the radicals R.sub.1, R.sub.2 and R.sub.3 represent hydrogen and the third represents an alkyl group containing from 2 to 12 carbon atoms. Mixtures of diisocyanates in which the described diisocyanate is a major substituent are also within the scope of this disclosure. Such compounds and mixtures are made by reacting a nitrobenzyl halide, an unsubstituted benzyl halide or a benzyl alcohol in the presence of a Friedel-Crafts catalyst with an alkylbenzene or a nitroalkylbenzene and then converting the nitro groups to amino groups by hydrogenation or reduction. The thus-produced amino compound is then phosgenated to form the diisocyanate.The compounds and mixtures of the present invention are useful in the production of polyurethane plastics.
    Type: Grant
    Filed: August 7, 1981
    Date of Patent: May 6, 1986
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Michael Brockelt
  • Patent number: 4405527
    Abstract: Polyisocyanates are prepared by reacting a polyamine solution with a phosgene solution. Excess phosgene and hydrogen chloride formed during the reaction are removed from the reaction mixture. The solvent is subsequently removed from the reaction mixture (e.g., by evaporation and condensation) and treated with a compound containing isocyanate reactive hydrogen atoms to convert any isocyanates present into urethanes and/or ureas. The thus-treated solvent may then be reused, preferably after any urethanes and/or ureas present in the solvent have been removed.
    Type: Grant
    Filed: July 12, 1982
    Date of Patent: September 20, 1983
    Assignee: Bayer Aktiengesellschaft
    Inventors: Gerhard Wegener, Hartmut Knofel, Gunther Ellendt, Marcel Petinaux
  • Patent number: 4259526
    Abstract: The instant invention is directed to a process for the preparation of mixtures of polyamines of the polyamino-polyaryl-polymethylene type whereby the proportion or the ortho-substituted products are substantially increased. This increase is brought about by adding the acid catalyst to the aromatic amine/formaldehyde reaction mixture in two or more stages.
    Type: Grant
    Filed: February 21, 1979
    Date of Patent: March 31, 1981
    Assignees: Bayer Aktiengesellschaft, Mobay Chemical Corporation
    Inventors: Kenneth L. Dunlap, Hartmut Knofel
  • Patent number: 4231952
    Abstract: This invention relates to an improved process for the production of aliphatic relatively low boiling monoisocyanates from the corresponding carbamic acid chlorides, comprising adding an at least equivalent quantity, based on the hydrogen chloride bound in the carbamic acid chloride, of a relatively high boiling organic monoisocyanate or polyisocyanate whose boiling point is higher than the boiling point of the relatively low boiling monoisocyanate to be produced, to the carbamic acid chloride, optionally dissolved in inert organic solvents and then distilling off the relatively low boiling monoisocyanate by heating and/or applying a vacuum, or by means of an inert gas stream.
    Type: Grant
    Filed: August 26, 1977
    Date of Patent: November 4, 1980
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Klaus Konig
  • Patent number: 4147724
    Abstract: This invention relates to a new and improved process for the preparation of polyamines based on diphenylmethane by acid condensation of aromatic amines with formaldehyde followed by processing of the condensation mixture. Compared with similar processes known in the art, the process according to the invention combines the advantage of requiring less distillation for processing the reaction mixture with the advantage of a wide scope for variation of the composition of the product finally obtained, particularly with regard to its concentration of 2,4'-isomers and greatly reduced concentration of 2,2'-isomers.
    Type: Grant
    Filed: December 17, 1976
    Date of Patent: April 3, 1979
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Gunther Ellendt
  • Patent number: 4094907
    Abstract: The instant invention is directed to a process for the preparation of multinuclear aromatic polyamines by condensation of aromatic amines with formaldehyde in the presence of aqueous acid catalysts followed by neutralization of the catalyst and processing of the resulting reaction mixture in known manner, characterized in that free amine is removed from the reaction mixture leaving the last condensation stage by means of a hydrophobic solvent, optionally after partial neutralization of the catalyst but before neutralization of the total quantity of catalyst put into the process, and the amine thus removed is returned to the catalyst-containing aqueous phase by return of the resulting amine-containing solvent phase into said aqueous, catalyst-containing phase at any point before the last condensation stage.
    Type: Grant
    Filed: December 17, 1976
    Date of Patent: June 13, 1978
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Gunther Ellendt
  • Patent number: 4093658
    Abstract: The instant invention is directed to a novel process for the production of aromatic polyamines.
    Type: Grant
    Filed: December 29, 1975
    Date of Patent: June 6, 1978
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Gunther Ellendt
  • Patent number: 4087459
    Abstract: The instant invention is directed to a process for the preparation of multinuclear aromatic polyamines by the condensation of aniline with formaldehyde in the presence of water and acid catalysts, in which the completely reacted aqueous condensation mixture is extracted with a hydrophobic solvent in extraction stage (I), optionally with the addition of aniline, the resulting solvent phase is worked-up in known manner to isolate the polyamine and the aqueous phase is recycled to the beginning of the process, the improvement characterised in that before the aqueous phase is returned to the beginning of the process, it is extracted in one or more separate extractors (II) with a hydrophobic solvent which may contain aniline and/or aniline/formaldehyde condensates with an increased proportion of ortho-isomers, the resulting solvent phase or phases is or are extracted with the aqueous acid condensation mixture in one or more separate extractors (III) at any one or more points after the first condensation stage and
    Type: Grant
    Filed: June 16, 1976
    Date of Patent: May 2, 1978
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Gunther Ellendt
  • Patent number: 4061678
    Abstract: The instant invention is directed to a novel process for the production of aromatic polyamines. The process of the invention comprisesA. condensing an aromatic amine with formaldehyde in the presence of a hydrophobic solvent and in the absence of an acid catalyst to produce a pre-condensate mixture containing the corresponding N,N'-disubstituted aminals,B. removing substantially all the water from said pre-condensate mixture to produce a first organic phase,C. extracting said first organic phase with an aqueous solution containing an acid catalyst thereby producing a second organic phase and an aqueous pre-condensate phase which contains said aminals,D. subjecting said aqueous pre-condensate phase to a rearrangement reaction thereby producing an aqueous condensation mixture containing said aromatic polyamines,E.
    Type: Grant
    Filed: December 29, 1975
    Date of Patent: December 6, 1977
    Assignee: Bayer Aktiengesellschaft
    Inventors: Hartmut Knofel, Gunther Ellendt
  • Patent number: 4025557
    Abstract: A process for condensing aromatic amines with formaldehyde in the presence of water is disclosed whereby an inhomogeneous mixture of a reaction product containing a large amount of 4,4'-diamino diphenylmethane is obtained which inhomogenity is due to a large quantity of water which is either present at the beginning of the condensation reaction or which if the reaction is carried out in the presence of relatively small amounts of water is obtained by the subsequent addition of water. The two phases are separated into an organic phase which is directly worked up by distillation without the necessity of an alkaline treatment. The aqueous phase is recycled to the beginning of the process. The process has the advantage of elimination of a salt free effluent, no consumption of acid catalyst and elimination of the need for alkaline reagents.
    Type: Grant
    Filed: November 27, 1974
    Date of Patent: May 24, 1977
    Assignee: Bayer Aktiengesellschaft
    Inventors: Willi Eifler, Hartmut Knofel
  • Patent number: 3996283
    Abstract: An improved process for the production of multi-nuclear aromatic polyamines by condensing an aromatic amine with formaldehyde in the presence of an acid catalyst, obtaining the condensation product in an aqueous medium and then extracting the aqueous condensation mixture with a hydrophobic solvent in order to obtain a solvent phase and a separate aqueous phase. Thereafter polyamine product is recovered from the solvent phase. If desired, polyamine product can be obtained from both the solvent phase and the aqueous phase. Alternatively, the aqueous phase can be recycled to the initial condensation step, thus providing a continuous process without loss of acid catalysts.
    Type: Grant
    Filed: July 30, 1973
    Date of Patent: December 7, 1976
    Assignee: Bayer Aktiengesellschaft
    Inventor: Hartmut Knofel
  • Patent number: 3952042
    Abstract: A process is provided for making a mixture of diisocyanate and polyisocyanates having more than two amino groups of the diphenylmethane series which has a low content of the o-isomers wherein a mixture of aniline and a polyamine prepared by condensation of aniline and formaldehyde is condensed with formaldehyde, at least 90% of the amino groups in the mixture being protonized with an acid, and phosgenating the resulting condensation product to form corresponding polyisocyanates.
    Type: Grant
    Filed: November 11, 1974
    Date of Patent: April 20, 1976
    Assignee: Bayer Aktiengesellschaft
    Inventor: Hartmut Knofel