Patents by Inventor Rudolf Kummer

Rudolf Kummer 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: 6350914
    Abstract: In a process for preparing amines of the general formula I where R1,R2,R3,R4,R5,R6 are hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C2-C20-alkynyl, C3-C20-cycloalkyl, C4-C20-alkyl-cycloalkyl, C4-C20-cycloalkyl-alkyl, aryl, C7-C20-alkylaryl or C7-C20-aralkyl, R1 and R2 are together a saturated or unsaturated divalent C3-C9-alkylene chain and R3 or R5 are C21-C200-alkyl, C21-C200-alkenyl or together a divalent C2-C12-alkylene chain, by reacting olefins of the general formula II where R3, R4, R5 and R6 are as defined above, with ammonia or primary or secondary amines of the general formula III where R1 and R2 are as defined above, at from 200 to 350° C. and pressures of from 100 to 300 bar in the presence of a heterogeneous catalyst, the heterogeneous catalyst used is a zeolite having an NES structure.
    Type: Grant
    Filed: July 21, 1997
    Date of Patent: February 26, 2002
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Matthias Dernbach
  • Patent number: 6143934
    Abstract: In a process for preparing amines of the general formula I ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 are hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.2 -C.sub.20 -alkynyl, C.sub.3 -C.sub.20 -cycloalkyl, C.sub.4 -C.sub.20 -alkylcycloalkyl, C.sub.4 -C.sub.20 -cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 -alkylaryl or C.sub.7 -C.sub.20 -aralkyl,R.sup.1 and R.sup.2 are together a saturated or unsaturated, divalent C.sub.3 -C.sub.9 -alkylene chain andR.sup.3 and R.sup.5 are each C.sub.21 -C.sub.200 -alkyl, C.sub.21 -C.sub.200 -alkenyl or together are a divalent C.sub.2 -C.sub.12 -alkylene chain,by reacting olefins of the general formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are as defined above, with ammonia or primary or secondary amines of the general formula III ##STR3## where R.sup.1 and R.sup.2 are as defined above, at from 200 to 350.degree. C.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: November 7, 2000
    Assignee: BASF Aktiengesellschaft
    Inventors: Uwe Dingerdissen, Rudolf Kummer, Peter Stops, Ulrich Muller, Jurgen Herrmann, Karsten Eller
  • Patent number: 5900508
    Abstract: A process for the preparation of amines by reacting an olefin with ammonia or a primary or secondary amine at a temperature of from 200 to 350.degree. C. and a pressure of from 100 to 300 bar in the presence of at least one zeolite having the specific structure type PSH-3, MCM-22 or SSZ-25, as identified by X-ray diffractogram, or mixtures of these zeolites. These specific catalysts are broadly identified as alumina zeolites and may be modified by ion exchange, doping with other metals, by dealumination to remove or replace the alumina content and by other well known after treatments such as calcination, acid-treatment and the like. Monoolefins are preferred reactants but di- and polyolefins also can be reacted with relatively high selectivity and less tendency toward polymerization.
    Type: Grant
    Filed: July 18, 1996
    Date of Patent: May 4, 1999
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Ulrich Muller, Rudolf Kummer, Peter Stops
  • Patent number: 5886226
    Abstract: A process for preparing amines of the general formula I ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.2 -C.sub.20 -alkynyl, C.sub.3 -C.sub.20 -cycloalkyl, C.sub.4 -C.sub.20 -alkylcycloalkyl, C.sub.4 -C.sub.20 -cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 -alkylaryl or C.sub.7 -C.sub.20 -aralkyl,R.sup.1 and R.sup.2 are together a saturated or unsaturated C.sub.3 -C.sub.9 -alkylene dichain, andR.sup.3 or R.sup.5 are each C.sub.21 -C.sub.200 -alkyl or C.sub.21 -C.sub.200 -alkenyl or together a C.sub.2 -C.sub.12 -alkylene dichain by reacting olefins of the general formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each as defined above, with ammonia or primary or secondary amines of the general formula III ##STR3## where R.sup.1 and R.sup.2 are each as defined above, at temperatures from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: January 29, 1998
    Date of Patent: March 23, 1999
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Peter Stops
  • Patent number: 5877352
    Abstract: A process for preparing amines of the formula I ##STR1## where R.sup.1,R.sup.2,R.sup.3,R.sup.4,R.sup.5,R.sup.6 are hydrogen, C.sub.1 - to C.sub.20 -alkyl, C.sub.2 - to C.sub.20 -alkenyl, C.sub.2 - to C.sub.20 -alkynyl, C.sub.3 - to C.sub.20 -cycloalkyl, C.sub.4 - to C.sub.20 -alkyl-cycloalkyl, C.sub.4 - to C.sub.20 -cycloalkyl-alkyl, aryl, C.sub.7 - to C.sub.20 -alkylaryl or C.sub.7 - to C.sub.20 -aralkyl,R.sup.1 and R.sup.2 jointly are a saturated or unsaturated C.sub.3 - to C.sub.9 -alkylene divalent chain andR.sup.3 or R.sup.5 are C.sub.21 - to C.sub.200 -alkyl, C.sub.21 - to C.sub.200 -alkenyl or jointly are a C.sub.2 - to C.sub.12 -alkylene divalent chain,by reacting olefins of the formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 have the abovementioned meanings, with ammonia or primary or secondary amines of the formula III ##STR3## where R.sup.1 and R.sup.2 have the abovementioned meanings, at from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: March 2, 1999
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer
  • Patent number: 5874621
    Abstract: Amines of the general formula I ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 : are each hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.2 -C.sub.20 -alkynyl, C.sub.3 -C.sub.20 -cycloalkyl, C.sub.4 -C.sub.20 -alkylcycloalkyl, C.sub.4 -C.sub.20 -cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 -alkylaryl or C.sub.7 -C.sub.20 -aralkyl,R.sub.1 and R.sup.2 together are a saturated or unsaturated C.sub.3 -C.sub.9 -alkylene chain andR.sup.3 or R.sup.5 is C.sub.21 -C.sub.200 -alkyl or C.sub.21 -C.sub.200 -alkenyl or R.sup.3 and R.sup.5 together are a C.sub.2 -C.sub.12 -alkylene chain,are prepared by reacting an olefin of the general formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 have the abovementioned meanings, with ammonia or a primary or secondary amine of the general formula III ##STR3## where R.sup.1 and R.sup.2 have the abovementioned meanings, at from 200.degree.0 to 350.degree. C.
    Type: Grant
    Filed: February 12, 1998
    Date of Patent: February 23, 1999
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Matthias Dernbach, Hans-Jurgen Lutzel
  • Patent number: 5840988
    Abstract: A process for preparing amines of the formula I ##STR1## where R.sup.1,R.sup.2,R.sup.3,R.sup.4,R.sup.5,R.sup.6 are hydrogen, C.sub.1 - to C.sub.20 -alkyl, C.sub.2 - to C.sub.20 -alkenyl, C.sub.2 - to C.sub.20 -alkynyl, C.sub.3 - to C.sub.20 -cycloalknyl, C.sub.4 - to C.sub.20 -alkyl-cycloalkyl, C.sub.4 - to C.sub.20 -cycloalkyl-alkyl, aryl, C.sub.7 - to C.sub.20 -alkylaryl or C.sub.7 - to C.sub.20 -aralkyl,R.sup.1 and R.sup.2 jointly are a saturated or unsaturated C.sub.3 - to C.sub.9 -alkylene divalent chain andR.sup.3 or R.sup.5 are C.sub.21 - to C.sub.200 -alkyl, C.sub.21 - to C.sub.200 -alkenyl or jointly are a C.sub.2 - to C.sub.12 -alkylene divalent chain,by reacting olefins of the formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 have the abovementioned meanings, with ammonia or primary or secondary amines of the formula III ##STR3## where R.sup.1 and R.sup.2 have abovementioned meanings, at from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: November 24, 1998
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer
  • Patent number: 5786510
    Abstract: A process for the preparation of amines of the general formula I ##STR1## in which R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 denote hydrogen, C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkynyl, C.sub.3 -C.sub.20 cycloalkyl, C.sub.4 -C.sub.20 alkylcycloalkyl, C.sub.4 -C.sub.20 cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 alkylaryl or C.sub.7 -C.sub.20 aralkyl,R.sup.1 and R.sup.2 together denote a saturated or unsaturated C.sub.3 -C.sub.9 alkylene dichain andR.sup.3 or R.sup.5 denotes C.sub.21 -C.sub.200 alkyl, C.sub.21 -C.sub.200 alkenyl or they together form a C.sub.2 -C.sub.12 alkylene dichain,by the reaction of olefins of the general formula II ##STR2## in which R.sup.3, R.sup.4, R.sup.5 and R.sup.6 have the aforementioned meanings,with ammonia or primary or secondary amines of the general formula III ##STR3## in which R.sup.1 and R.sup.2 have the aforementioned meanings, at temperatures ranging from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: January 16, 1997
    Date of Patent: July 28, 1998
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Peter Stops
  • Patent number: 5780681
    Abstract: Amines of general formula I ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.2 -C.sub.20 -alkynyl, C.sub.3 -C.sub.20 -cycloalkyl, C.sub.4 -C.sub.20 -alkylcycloalkyl, C.sub.4 -C.sub.20 -cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 -alkylaryl or C.sub.7 -C.sub.20 -aralkyl,R.sup.1 and R.sup.2 together form a saturated or unsaturated C.sub.3 -C.sub.9 -alkylene chain andR.sup.3 or R.sup.5 is C.sub.21 -C.sub.200 -alkyl or C.sub.21 -C.sub.200 -alkenyl, or R.sup.3 and R.sup.5 together form a C.sub.2 -C.sub.12 -alkylene chain,are prepared by reacting an olefin of the general formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 have the above-mentioned meanings, with ammonia or primary or secondary amines of the general formula III ##STR3## where R.sup.1 and R.sup.2 have the abovementioned meanings, at from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: June 5, 1997
    Date of Patent: July 14, 1998
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Michael Hesse
  • Patent number: 5780680
    Abstract: In a process for preparing amines of the formula I ##STR1## where R.sup.1,R.sup.2,R.sup.3,R.sup.4,R.sup.5,R.sup.6 are hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.2 -C.sub.20 -alkynyl, C.sub.3 -C.sub.20 -cycloalkyl, C.sub.4 -C.sub.20 -alkyl-cycloalkyl, C.sub.4 -C.sub.20 -cycloalkyl-alkyl, aryl, C.sub.7 -C.sub.20 -alkylaryl or C.sub.7 -C.sub.20 -aralkyl,R.sup.1 and R.sup.2 together form a saturated or unsaturated, divalent C.sub.3 -C.sub.9 -alkylene chain andR.sup.3 and R.sup.5 are C.sub.21 -C.sub.200 -alkyl, C.sub.21 -C.sub.200 -alkenyl or together form a divalent C.sub.2 -C.sub.12 -alkylene chain,by reating olefins of the formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are as defined above, with ammonia or primary or secondary amines of the formula III ##STR3## where R.sup.1 and R.sup.2 are as defined above, at from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: April 18, 1997
    Date of Patent: July 14, 1998
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Ulrich Muller
  • Patent number: 5773660
    Abstract: A process for preparing amines of the formula I ##STR1## where R.sup.1,R.sup.2,R.sup.3,R.sup.4,R.sup.5 and R.sup.6 are each hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.2 -C.sub.20 -alkynyl, C.sub.3 -C.sub.20 -cycloalkyl, C.sub.4 -C.sub.20 -alkylcycloalkyl, C.sub.4 -C.sub.20 -cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 -alkylaryl or C.sub.7 -C.sub.20 -aralkyl,R.sup.1 and R.sup.2 are together a saturated or unsaturated C.sub.3 -C.sub.9 -alkylene dichain, andR.sup.3 or R.sup.5 is C.sub.21 -C.sub.200 -alkyl or C.sub.21 -C.sub.200 -alkenyl or together they are a C.sub.2 -C.sub.12 -alkylene dichain,by reacting olefins of the formula II ##STR2## where R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each as defined above, with ammonia or primary or secondary amines of the formula III ##STR3## where R.sup.1 and R.sup.2 are each as defined above, at temperatures from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: January 21, 1997
    Date of Patent: June 30, 1998
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Eugen Gehrer
  • Patent number: 5739405
    Abstract: A process for the preparation of amines of the general formula I ##STR1## in which R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 denote hydrogen, C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl, C.sub.2 -C.sub.20 alkynyl, C.sub.3 -C.sub.20 cycloalkyl, C.sub.4 -C.sub.20 alkylcycloalkyl, C.sub.4 -C.sub.20 cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 alkylaryl, or C.sub.7 -C.sub.20 aralkyl,R.sup.1 and R.sup.2 together denote a saturated or unsaturated C.sub.3 -C.sub.9 alkylene dichain andR.sup.3 or R.sup.5 denotes C.sub.21 -C.sub.200 alkyl, C.sub.21 -C.sub.200 alkenyl or they together form a C.sub.2 -C.sub.12 alkylene dichain,by the reaction of olefins of the general formula II ##STR2## in which R.sup.3, R.sup.4, R.sup.5, and R.sup.6 have the above meanings, with ammonia or primary or secondary amines of the general formula III ##STR3## in which R.sup.1 and R.sup.2 have the above meanings, at temperatures ranging from 200.degree. to 350.degree. C.
    Type: Grant
    Filed: December 4, 1996
    Date of Patent: April 14, 1998
    Assignee: BASF Aktiengesellschaft
    Inventors: Karsten Eller, Rudolf Kummer, Peter Stops
  • Patent number: 5530127
    Abstract: A process for the preparatiion of an amine which comprises reacting a primary or secondary alcohol and a nitrogen compound selected from the group consisting of ammonia and primary and secondary amines, at temperatures of from 80.degree. to 250.degree. C. and pressures of from 1 to 400 bar using hydrogen in the presence of a zirconium/copper/nickel catalyst, wherein the catalytically active material contains from 20 to 85 wt % of oxygen-containing zirconium compounds, calculated as ZrO.sub.2, from 1 to 30 wt % of oxygen-containing compounds of copper, calculated as CuO, from 30 to 70 wt % of oxygen-containing compounds of nickel, calculated as NiO, from 0.1 to 5 wt % of oxygen-containing compounds of molybdenum, calculated as MoO.sub.3 and from 0 to 10 wt % of oxygen-containing compounds of aluminum and/or manganese, calculated as Al.sub.2 O.sub.3 or MnO.sub.2, respectively.
    Type: Grant
    Filed: August 1, 1995
    Date of Patent: June 25, 1996
    Assignee: BASF Aktiengesellschaft
    Inventors: Wolfgang Reif, Lothar Franz, Peter Stops, Volkmar Menger, Rainer Becker, Rudolf Kummer, Siegfried Winderl
  • Patent number: 5434291
    Abstract: A process for the preparation of aminopropionitriles of the general formula I ##STR1## in which R denotes hydrogen or methyl, wherein ammonia is caused to react with an acrylonitrile of the general formula II ##STR2## In which the substituent has the aforementioned meanings, in a molar ratio of from 1:1 to 500:1 over a heterogenic catalyst at temperatures ranging from 40.degree. to 180.degree. C. and pressures ranging from 10 to 350 bar.
    Type: Grant
    Filed: June 1, 1994
    Date of Patent: July 18, 1995
    Assignee: BASF Aktiengsellschaft
    Inventors: Tom Witzel, Rudolf Kummer, Franz Merger, Guido Voit, Martin Brudermueller, Claus-Ulrich Priester, Wolfgang Harder
  • Patent number: 5189182
    Abstract: 5-Methylbutyrolactone is prepared by a process in which a pentenoic ester of the formula IX--CO.sub.2 R (I),where X is CH.sub.2 .dbd.CH--CH.sub.2 --CH.sub.2 --, CH.sub.3 --CH.dbd.CH--CH.sub.2 -- or CH.sub.3 --CH.sub.2 --CH.dbd.CH-- and R is alkyl, cycloalkyl, aralkyl or aryl, or a mixture of these esters is reacted with water at from 50.degree. to 350.degree. C. in the presence or absence of a diluenta) over a zeolite and/or phosphate catalyst orb) in the presence of from 0.01 to 0.25 mole of a sulfonic acid, a Lewis acid and/or a non-oxidizing mineral acid per mole of pentenoic ester or over from 0.
    Type: Grant
    Filed: August 25, 1988
    Date of Patent: February 23, 1993
    Assignee: BASF Aktiengesellschaft
    Inventors: Rudolf Kummer, Heinz-Walter Schneider, Werner Bertleff, Rolf Fischer, Uwe Vagt, Fritz Naeumann, Wolfgang Hoelderich, Matthias Schwarzmann
  • Patent number: 5151541
    Abstract: A process for the preparation of dialkyl carbonates of the general formula I ##STR1## in which R.sup.1 denotes C.sub.1 -C.sub.10 -alkyl, by reaction of alcohols R.sup.1 OH with a gaseous carbon monoxide/oxygen mixture in the presence of a copper catalyst and a co-solvent at elevated temperature and pressure wherein the co-solvent used is a cyclic urea of the general formula II ##STR2## in which n is equal to 2, 3 or 4 and R.sup.2 denotes hydrogen or C.sub.1 -C.sub.4 -alkyl.
    Type: Grant
    Filed: August 6, 1990
    Date of Patent: September 29, 1992
    Assignee: BASF Aktiengesellschaft
    Inventors: Klaus Joerg, Rudolf Kummer, Franz-Josef Mueller
  • Patent number: 5142087
    Abstract: A process for the continuous synthesis of dialkyl carbonates of the general formula I ##STR1## in which R denotes C.sub.1 -C.sub.4 -alkyl, by reaction of C.sub.1 -C.sub.
    Type: Grant
    Filed: August 8, 1990
    Date of Patent: August 25, 1992
    Assignee: BASF Aktiengesellschaft
    Inventors: Klaus Joerg, Franz-Josef Mueller, Wolfgang Harder, Rudolf Kummer
  • Patent number: 5003102
    Abstract: 5-Formylvaleric esters are prepared by a process which comprises the following steps:(a) Hydroformylation of a pentenoic ester by reaction with carbon monoxide and hydrogen at elevated temperatures and under superatmospheric pressure in the presence of a carbonyl complex of a metal of group 8 of the Periodic Table with formation of a mixture of 5-, 4- and 3-formylvaleric esters,(b) Isolation of the 5-formylvaleric ester from the resulting mixture of 5-, 4- and 3-formylvaleric esters, a mixture essentially consisting of 4- and 3-formylvaleric esters remaining,(c) Cleavage of the mixture essentially consisting of 4- and 3-formylvaleric esters at from 50.degree. to 400.degree. C. in the presence of a catalyst to give pentenoic esters and(d) Recycling of the pentenoic esters to stage (a).
    Type: Grant
    Filed: June 15, 1988
    Date of Patent: March 26, 1991
    Assignee: BASF Aktiensellschaft
    Inventors: Werner Bertleff, Rolf Fischer, Rudolf Kummer, Franz Merger, Heinz-Walter Schneider
  • Patent number: 4950797
    Abstract: A process for the preparation of carbonyl compounds by catalyzed isomerization of allyl alcohols in a tertiary phosphine or phosphite ester in the presence of a rhodium compound at a temperature of from 80.degree. C. to 180.degree. C., a carrier gas being passed through the reaction mixture and the carbonyl compound being separated from the emergent gas mixture by cooling.
    Type: Grant
    Filed: June 1, 1988
    Date of Patent: August 21, 1990
    Assignee: BASF Aktiengesellschaft
    Inventors: Rudolf Kummer, Werner Bertleff, Michael Roeper
  • Patent number: 4931590
    Abstract: Adipic acid is prepared by a process which comprises the following steps:(a) Hydroformylation of a pentenoic ester by reaction with carbon monoxide and hydrogen at elevated temperatures and under superatmospheric pressure in the presence of a cobalt carbonyl or rhodium carbonyl complex with formation of a mixture of 5-, 4- and 3-formylvaleric esters,(b) isolation of the 5-formylvaleric ester from the resulting mixture of 5-, 4- and 3-formylvaleric esters, a mixture essentially consisting of 4- and 3-formylvaleric esters remaining,(c) dehydrocarbonylation of the mixture consisting essentially of 4- and 3-formylvaleric esters in the presence of one or more elements of subgroup 8 of the Periodic Table at from 50.degree. to 400.degree. C.
    Type: Grant
    Filed: June 10, 1988
    Date of Patent: June 5, 1990
    Assignee: BASF Aktiengesellschaft
    Inventors: Rudolf Kummer, Franz Merger, Werner Bertleff, Rolf Fischer