Patents by Inventor Manfred Lenthe
Manfred Lenthe 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: 4988829Abstract: A process for making the known fungicide intermediate 2-(4-chlorophenyl ethyl)-2-tert.-butyloxirane of the formula ##STR1## comprising (a) mixing a solution of trimethylsulphonium bromide of the formula(CH.sub.3).sub.3 S.sup..sym. Br.sup..crclbar. (II)in a methanol/toluene mixture with preheated toluene and simultaneously distilling off a methanol/toluene mixture at a temperature between 65.degree. and 110.degree. C. until a suspension having a solids content between 10 and 70% by weight is formed, and(b) reacting the suspension of trimethylsulphonium bromide in toluene thus obtained with 1-(4-chlorophenyl)-4,4-dimethylpentan-3-one of the formula ##STR2## in the presence of solid potassium hydroxide, diethylene glycol and water at a temperature between 20.degree. and 120.degree. C.Type: GrantFiled: June 30, 1989Date of Patent: January 29, 1991Assignee: Bayer AktiengessellschaftInventors: Paul Fiedler, Martin Littmann, Manfred Lenthe, Achim Noak, Gerd Siekmann
-
Patent number: 4683308Abstract: In the preparation of a 2-arylamino-4,6-dichloro-s-triazine of the formula ##STR1## in which R.sup.1 is an optionally substituted aryl radical, andR.sup.2 is hydrogen or alkyl,by reacting cyanuric chloride of the formula ##STR2## with a virtually water-insoluble arylamine of the formula ##STR3## at a temperature between 0.degree. and 100.degree. C., the improvement which comprises effecting the reaction in water at an acid pH in the presence of a virtually water-insoluble organic solvent. The resulting aqueous phase contains the triazine in such high purity and concentration that it can be used without further purification. The organic solvent can be recycled.Type: GrantFiled: January 21, 1986Date of Patent: July 28, 1987Assignee: Bayer AktiengesellschaftInventors: Andreas Gunther, James R. Malone, Manfred Lenthe, Hans-Walter Hohl
-
Patent number: 4647676Abstract: A process for the isolation of a dihydroxybenzenemonoether from a reaction mixture containing solvent, ether and unreacted dihydroxybenzene, comprising contacting the reaction mixture with at least one hydrocarbon which is not miscible or only partially miscible with the reaction mixture, the ether selectively entering the hydrocarbon. Advantageously the reaction for the preparation of the monoether is carried out in an alcohol, a ketone, a dipolar aprotic solvent or a polyhydroxyalkyl ether, or a mixture thereof with water, the hydrocarbon used as extracting agent has a boiling point between about 80.degree. and 300.degree. C., and the extraction is carried out in the presence of water whereby there is an increase in the selectivity of the extraction.Type: GrantFiled: May 23, 1984Date of Patent: March 3, 1987Assignee: Bayer AktiengesellschaftInventors: Manfred Lenthe, Udo Allenbach, Gerhard Buttner, Karl-Friedrich Christmann
-
Patent number: 4486611Abstract: A process for the isolation of a dihydroxybenzene-monoether from a reaction mixture containing solvent, ether and unreacted dihydroxybenzene, comprising contacting the reaction mixture with at least one hydrocarbon which is not miscible or only partially miscible with the reaction mixture, the ether selectively entering the hydrocarbon. Advantageously the reaction for the preparation of the monoether is carried out in an alcohol, a ketone, a dipolar aprotic solvent or a polyhydroxyalkyl ether, or a mixture thereof with water, the hydrocarbon used as extracting agent has a boiling point between about 80.degree. and 300.degree. C., and the extraction is carried out in the presence of water whereby there is an increase in the selectivity of the extraction.Type: GrantFiled: August 30, 1982Date of Patent: December 4, 1984Assignee: Bayer AktiengesellschaftInventors: Manfred Lenthe, Udo Allenbach, Gerhard Buttner, Karl-Friedrich Christmann
-
Patent number: 4383126Abstract: A process for the preparation of a monoalkyl ether of a hydroxyphenol of the formula ##STR1## in which Z each independently is hydrogen or a substituent which is stable under the reaction conditions,R is lower alkyl, andn is 1, 2, 3 or 4,comprising reacting a hydroxyphenol of the formula ##STR2## with an alkyl halide, alkyl sulphonate or aryl sulphonate alkylating agent of the formulaR--Xin which X is a halogen atom, or an alkylsulphonyloxy or arylsulphonyloxy radical,at a temperature from about 130.degree. C. to 200.degree. C. and in the presence of an alkali metal base or alkaline earth metal base and of a diluent comprising a polyhydroxyalkyl ether having at least one OH group. Advantageously the base is sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate, the hydroxyphenol is pyrocatechol, the alkylating agent is isopropyl chloride, isopropyl C.sub.Type: GrantFiled: October 26, 1981Date of Patent: May 10, 1983Assignee: Bayer AktiengesellschaftInventors: Gerhard Buttner, Artur Judat, Udo Allenbach, Manfred Lenthe
-
Patent number: 4360479Abstract: This invention relates to a new process for the preparation of acyl cyanides of the general formulaR.sup.1 --CO--CN (I)wherein R.sup.1 is an optionally substituted alkyl radical up to 18 carbon atoms, an optionally substituted cycloalkyl radical with 3 to 12 carbon atoms, an optionally substituted aryl radical or an optionally substituted 5- or 6-membered heterocyclic radical, which can additionally also be fused with a benzene ring, which process comprises reacting a carboxylic acid anhydride of the formulaR.sup.1 --CO--O--CO--R.sup.1 (II)with an alpha-hydroxynitrile of the formula ##STR1## in which R.sup.2 and R.sup.3 are identical or different and represent a hydrogen atom, an optionally substituted alkyl radical with 1 to 18 carbon atoms, an optionally substituted cycloalkyl radical with 3 to 12 carbon atoms, an optionally substituted aryl radical or an optionally substituted 5- or 6-membered heterocyclic radical, which can additionally also be fused with a benzene ring.Type: GrantFiled: June 24, 1981Date of Patent: November 23, 1982Assignee: Bayer AktiengesellschaftInventors: Kurt Findeisen, Hans Kratzer, Manfred Lenthe
-
Patent number: 4321204Abstract: In the preparation of a 7-hydroxycoumaran of the formula ##STR1## in which Z is a hydrogen atom or a substituent which is inert under the subsequent reaction conditions,R.sup.1 is a hydrogen atom or a C.sub.1 to C.sub.4 -alkyl radical, andn is 1, 2 or 3wherein a pyrocatechol of the formula ##STR2## is reacted with an allyl compound of the formula ##STR3## in which Y is a halogen atom, a C.sub.1 to C.sub.4 -alkyl-sulphonate radical or an aryl-sulphonate radical,to form the mono-ether of the pyrocatechol in a first stage, and in a second stage, of the pyrocatechol monoether formed in the first stage is rearranged to a 3-alkenylpyrocatechol, and in a third stage the 3-alkenylpyrocatechol formed in the second stage, is cyclized, the improvement which comprises stages. (b) carrying out the second stage at a pH of about 2-8.Type: GrantFiled: July 21, 1980Date of Patent: March 23, 1982Assignee: Bayer AktiengesellschaftInventors: Gerhard Buttner, Karl-Friedrich Christmann, Manfred Lenthe, Udo Allenbach
-
Patent number: 4216332Abstract: In the preparation of chlorinated N-methyl-imidazoles and N-methyl-imidazolines of the formula ##STR1## in which n represents the number 0, 1, 2 or 3 andm represents the number 0 or 1, a double bond being present between the C atoms in the 4-position and 5-position when m is 0, and a single bond being present when m is 1,by chlorinating N,N-dimethylaminoacetonitrile of the formula(CH.sub.3).sub.2 N--CH.sub.2 --CNor its hydrochloride, the improvement which comprises introducing aminoacetonitrile or its hydrochloride into a mixture of its chlorination products, with simultaneous addition of chlorine gas, in the absence of a solvent, at a temperature from about 70.degree. to 150.degree. C. The product can be further chlorinated at 130.degree. to 220.degree. C. to produce tetrachloro-ethylene-bis-isocyanide dichloride.Type: GrantFiled: December 29, 1978Date of Patent: August 5, 1980Assignee: Bayer AktiengesellschaftInventors: Manfred Lenthe, Gerhard Dankert
-
Patent number: 4191711Abstract: A process for the preparation of 3,4-dichlorobenzotrichloride, 3,4,5-trichlorobenzotrichloride, 2,4,5-trichlorobenzotrichloride or 2,3,4,5-tetrachlorobenzotrichloride which comprises contacting p-chlorobenzotrichloride of the formula ##STR1## with chlorine or an agent which releases chlorine at a temperature between 0.degree. C. and 180.degree. C. in the presence of an iron (III) chloride or aluminum chloride catalyst or a mixture of iron (III) chloride or aluminum chloride with sulfur dichloride or disulfur dichloride.Type: GrantFiled: July 17, 1978Date of Patent: March 4, 1980Assignee: Bayer AktiengesellschaftInventors: Manfred Lenthe, Hans-Helmut Schwarz
-
Patent number: 4176133Abstract: In the recovery of N,N-dimethylaminoacetonitrile from a mixture thereof with water by extraction with an organic solvent thereby to form an aqueous phase and an organic solvent phase containing the nitrile, separating the organic phase, and recovering the nitrile from the organic solvent, the improvement which comprises employing 1,2-dichlorobenzene as the organic solvent. Recovery of the nitrile from the organic solvent can be accomplished by distilling of the nitrile, the undistilled solvent being recycled for further use.Type: GrantFiled: October 19, 1978Date of Patent: November 27, 1979Assignee: Bayer AktiengesellschaftInventors: Manfred Lenthe, Gerhard Dankert