Patents by Inventor Gunter Prescher
Gunter Prescher 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).
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Patent number: 5026925Abstract: The nuclear hydroxylation of phenol can be carried out in an industrially very simple manner and with at least the yields obtained with the known methods as well as with very good selectivities by means of using aqueous hydrogen peroxide with the simultaneous addition of sulfur dioxide or selenium dioxide as catalyst.Type: GrantFiled: January 27, 1987Date of Patent: June 25, 1991Assignee: Degussa AktiengesellschaftInventors: Karl-Heinz Drauz, Axel Kleeman, Gunter Prescher, Gebhard Ritter
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Patent number: 4921983Abstract: In the continuous epoxidation of olefins with percarboxylic acids, the alkane component which normally accumulates during the circulation of the olefin is reduced by branching off a partial current from the recycled olefin and by additional epoxidation of this olefin with percarboxylic acids as well as a subsequent separation from the epoxide.Type: GrantFiled: July 26, 1989Date of Patent: May 1, 1990Assignee: Degussa AktiengesellschaftInventors: Rainer Siegmeier, Willi Hofen, Gunter Prescher, Helmut Maurer
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Patent number: 4879057Abstract: Aqueous bleaching agent suspensions based on a water-soluble peroxycarboxylic acid suspended in a carrier liquid in the presence of an organic thickening agent and of an acidifying agent exhibit an improved storage resistance over known suspensions with this base. This is achieved by means of pourable to pasty bleaching agent suspensions which contain a xanthan polysaccharide or agar polysaccharide as thickening agent and, in addition, a hydrate-forming neutral salt which desensitizes peroxycarboxylic acids. Preferred suspensions exhibit a pH of 2-5 and contain 10-30% by wt. diperoxydodecanedioic acid, 5-20% by wt. sodium sulfate and 0.1-1.0% by wt. xanthan. The use of non-dried, hydrophilized and optionally in situ desensitized peroxycarboxylic acids is especially preferred.The bleaching agent suspensions are prepared by homogeneously suspending the peroxycarboxylic acid in the thickened carrier liquid.Type: GrantFiled: March 16, 1988Date of Patent: November 7, 1989Assignee: Degussa AktiengesellschaftInventors: Manfred Dankowski, Thomas Lieser, Gunter Prescher, Wolfgang Leonhardt, Manfred Diehl
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Patent number: 4825011Abstract: The nuclear hydroxylation of substituted phenols is performed by using aqueous hydrogen peroxide in the presence of sulfur dioxide or selenium dioxide as catalyst in a simple manner with very good space-time yields and good product yields.Type: GrantFiled: December 4, 1987Date of Patent: April 25, 1989Assignee: Degussa AGInventors: Karl-Heinz Drauz, Axel Kleeman, Gunter Prescher, Gebhard Ritter
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Patent number: 4790949Abstract: Aqueous bleaching agent suspensions based on a water-insoluble peroxycarboxylic acid suspended in a carrier liquid in the presence of a colloidal silicic acid and of an acidifying agent which exhibit, in comparision to known suspensions with this base, an improved storage resistance and are more economical to prepare. This result is achieved by means of pourable-to-pasty bleaching agent suspensions which contain 0.1 to 9% by weight silicic acid in relation to the suspension and contain a hydrate-forming neutral salt which desensitizes peroxycarboxylilc acids, in an amount of 10 to 400% by weight, calculated hydrate-free and in relation to peroxycarboxylic acid added. Preferred bleaching agent suspensions contain 10-30% by weight diperoxydodecanedioic acid, 5-20% by weight sodium sulfate and 2 to 6% by weight pyrogenic silicic acid, each in relation to the suspension. The use of non-dried, hydrophilized and optionally in situ-desensitized peroxycarboxylic acids is especially preferred.Type: GrantFiled: March 16, 1988Date of Patent: December 13, 1988Assignee: Degussa AktiengesellschaftInventors: Manfred Dankowski, Thomas Lieser, Gunter Prescher, Wolfgang Leonhardt
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Patent number: 4720593Abstract: There is disclosed a process for the production of 1-methylcyclopropanecarboxaldehyde of the formula ##STR1## comprising treating 4-chloro-2-methyl-butanal of the formula ##STR2## at a temperature between -40.degree. and +7.degree. C. in an inert solvent with a 1.0 to 10.0 fold molar amount of a strong, non-nucleophilic base.Type: GrantFiled: October 22, 1986Date of Patent: January 19, 1988Assignee: Degussa AktiengesellschaftInventors: Juan Andrade, Gunter Prescher, Klaus Kohler
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Patent number: 4691062Abstract: 4-chloro-butanals of the formula ##STR1## where R is hydrogen or a straight or branched chain alkyl group of 1 to 4 carbon atoms are produced by reacting the corresponding 1,1-dimethoxy-4-hydroxybutane at a temperature between -20.degree. and +80.degree. C. in the presence of triphenylphosphine with carbon tetrachloride and hydrolyzing the 1,1-dimethoxy-4-chloro-butane obtained in acid medium.Type: GrantFiled: October 22, 1986Date of Patent: September 1, 1987Assignee: Degussa AktiengesellschaftInventors: Juan Andrade, Gunter Prescher, Klaus Kohler
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Patent number: 4680420Abstract: A process is described for producing 2,5-dimethoxytetrahydrofuran and 2,5-diethoxytetrahydrofuran by treating 4,4-dimethoxy-1-butanal and 4,4-diethoxy-1-butanal with a strongly acidic ion exchange resin at a temperature of between 0.degree. and 70.degree. C.Type: GrantFiled: December 1, 1986Date of Patent: July 14, 1987Assignee: Degussa AktiengesellschaftInventors: Juan Andrade, Gunter Prescher
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Patent number: 4626603Abstract: Aliphatic or cyclic epoxides containing 3 to 8 carbon atoms which are present in aromatic hydrocarbons or halohydrocarbons are saponified continuously and directly to vicinal diols without the use of high temperatures and pressures which would otherwise be necessary. The saponification is acid catalyzed.Type: GrantFiled: November 15, 1985Date of Patent: December 2, 1986Assignee: Degussa AktiengesellschaftInventors: Rainer Siegmeier, Gunter Prescher, Helmut Maurer
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Patent number: 4621072Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.Type: GrantFiled: February 26, 1985Date of Patent: November 4, 1986Assignee: Degussa AktiengesellschaftInventors: Dietrich Arntz, Gunter Prescher, Werner Burkhardt, Johannes Heilos, Reinhard Manner
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Patent number: 4608443Abstract: The preparation of 1,4-butandial (succindialdehyde) is obtained using acrolein. The acrolein is first converted with an alkanol into 3,3-dialkoxy-1-propene and this is then hydroformylated in the presence of hydridotristriphenylphosphine-rhodiumcarbonyl mixed with triphenylphosphine or triphenylphosphite as the catalyst. The thereby obtained 4,4-dialkoxy-butanal is removed from the hydroformylation product by means of distillation and is then hydrolyzed to 1,4-butandial.Type: GrantFiled: January 24, 1985Date of Patent: August 26, 1986Assignee: Degussa AktiengesellschaftInventors: Juan Andrade, Gunter Prescher, Marc Samson
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Patent number: 4605795Abstract: There is provided a process for the continuous production of pentanediol-1,2 comprising epoxidizing pentene in a completely homogeneous phase with perpropionic acid in benzene to 1-pentene oxide and directly saponifying the pentene oxide-1 without isolation. High yields and a high degree of purity of pentanediol-1,2 are obtained.Type: GrantFiled: November 15, 1985Date of Patent: August 12, 1986Assignee: Degussa AktiengesellschaftInventors: Rainer Siegmeier, Gunter Prescher, Helmut Maurer, Gunter Hering
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Patent number: 4579979Abstract: A method of preparation for acetals utilizing saturated or unsaturated aldehydes, in particular, the preparation of dimethylacetals of acetaldehyde, acrolein and methacrolein. The production of the acetal takes place in a liquid phase in the presence of a solid acid catalyst, such as a strongly acidic ion exchange resin or zeolite. The conversion mixture is extracted by means of water and by means of water insoluble organic solvents. There is obtained not only the desired acetals, but in addition also the unconverted initial quantities of the starting materials by a simple method and with very good yields.Type: GrantFiled: January 24, 1985Date of Patent: April 1, 1986Assignee: Degussa AktiengesellschaftInventors: Juan Andrade, Dietrich Arntz, Michael Kraft, Gunter Prescher
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Patent number: 4539409Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.Type: GrantFiled: October 18, 1983Date of Patent: September 3, 1985Assignee: Degussa AktiengesellschaftInventors: Dietrich Arntz, Gunter Prescher, Werner Burkhardt, Johannes Heilos, Reinhard Manner
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Patent number: 4521618Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.Type: GrantFiled: October 18, 1983Date of Patent: June 4, 1985Assignee: Degussa AktiengesellschaftInventors: Dietrich Arntz, Gunter Prescher, Werner Burkhardt, Johannes Heilos, Reinhard Manner
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Patent number: 4447614Abstract: Crude nicotinamide is purified by a recrystallization and thereby is particularly freed from nicotinic acid and salts of nicotinic acid. As solvent there is used 2-methylpropanol-1 containing water. The warm solution after dissolving the crude nicotinamide is treated with ion exchangers.Type: GrantFiled: July 29, 1981Date of Patent: May 8, 1984Assignee: Degussa AktiengesellschaftInventors: Helmut Beschke, Franz-Ludwig Dahm, Heinz Friedrich, Gunter Prescher
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Patent number: 4447615Abstract: Crude nicotinamide is purified by a recrystallization and in this way freed especially from nicotinic acid and salts of nicotinic acid. As solvent there is used a 2-methylpropanol-1 containing water. The recrystallization takes place at a pH between about 7 and 10.Type: GrantFiled: July 29, 1981Date of Patent: May 8, 1984Assignee: Degussa AktiengesellschaftInventors: Helmut Beschke, Franz-Ludwig Dahm, Heinz Friedrich, Gunter Prescher
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Patent number: 4442308Abstract: A process is disclosed for preparing acrolein from propylene and methacrolein from isobutylene or tertiary butanol, by oxidation in oxygen-containing gas mixtures on specially prepared coated catalysts comprised of an inert support and a coating, enclosing this support, of an oxidic catalyst material containing the elements nickel, cobalt, iron, bismuth, phosphorus, molybdenum and tantalum or samarium and, if appropriate, also alkali metal or alkaline earth metal in certain atomic ratios. This coated catalyst is obtained by spraying a suspension of the starting material for the coating, which suspension contains a binder and, if appropriate, a pore-former, from above in an increasing amount onto a bed of the support, which bed is mechanically agitated and loosened up by a gas stream blow in from below, the ratio between suspending medium sprayed on and removed again by the gas stream remaining approximately constant.Type: GrantFiled: June 21, 1982Date of Patent: April 10, 1984Assignee: Degussa AktiengesellschaftInventors: Dietrich Arntz, Gunter Prescher, Johannes Heilos
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Patent number: 4150241Abstract: Pure racemic acid (dl-tartaric acid) and meso tartaric acid are produced by reaction of an alkali maleate with aqueous hydrogen peroxide in the presence of an alkali tungstate in a process wherein the molar ratio of hydrogen peroxide to maleic acid is greater than 1:1 and the alkali salt of cis-epoxysuccinic acid formed together with the alkali tungstate, in a given case after destroying the excess hydrogen peroxide, are converted to free cis-epoxysuccinic acid and free tungstic acid by leading them over a strongly acidic cation exchanger, whereupon the hydrolysis of the free cis-epoxysuccinic acid to racemic acid and meso-tartaric acid can take place either in the presence of or the absence of the free tungstic acid, whereby the tungstic acid in the case of catalyst free hydrolysis before, and in the case of catalyst containing hydrolysis after this hydrolysis is removed with an anion exchanger and the racemic acid is then in known manner crystallized out of the tungstic acid free hydrolysis mixture by lowerType: GrantFiled: February 9, 1976Date of Patent: April 17, 1979Assignee: Deutsche Gold- und Silber-Scheideanstalt vormals RoesslerInventors: Gunter Prescher, Gerd Schreyer
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Patent number: RE31381Abstract: Process for continuous production of propylene oxide (FIG. 1) from propylene and aqueous hydrogen peroxide. The aqueous hydrogen peroxide is first reacted with propionic acid in the presence of acid catalyst to form perpropionic acid (1). The perpropionic acid is taken up by extraction in benzene (5, 18) and following drying of the benzene solution (21), the perpropionic acid in the solution is reacted with propylene (24) for oxidation of the propylene to propylene oxide and conversion of the perpropionic acid back to propionic acid. The reaction mixture is worked up to separate propylene oxide, propionic acid and benzene (30, 32, 37, 39), and the latter two are recycled. In the benzene extraction (5, 18), an aqueous raffinate (7) is formed containing hydrogen peroxide and acid catalyst.Type: GrantFiled: February 14, 1980Date of Patent: September 13, 1983Assignees: Bayer Aktiengesellschaft, Deutsche Gold-und Silber-ScheideanstaltInventors: Gunter Prescher, Gerd Schreyer, Otto Weiberg, Rolf Wirthwein, Helmut Waldmann, Hermann Seifert, Wulf Schwerdtel, Wolf Swodenk