Patents by Inventor Rangasamy Pitchai
Rangasamy Pitchai 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: 6194591Abstract: An olefin epoxidation process is described. The process comprises epoxidizing an olefin with hydrogen peroxide in the presence of a modified titanium zeolite catalyst in water solvent. The titanium zeolite catalyst is modified with a platinum, palladium or copper compound. The modified catalyst unexpectedly increases olefin epoxidation activity.Type: GrantFiled: April 27, 2000Date of Patent: February 27, 2001Assignee: ARCO Chemical Technology, L.P.Inventors: Roger A. Grey, Rangasamy Pitchai
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Patent number: 6083870Abstract: Propylene is oxidized to propylene oxide in the vapor phase using an oxygen-containing gas and a supported silver catalyst comprising silver and a support comprised in whole or in substantial part of certain alkaline earth metal compounds. The alkaline earth metal compound may, for example, be a calcium compound such as calcium titanate, tribasic calcium phosphate, calcium molybdate, or calcium fluoride, a magnesium compound such as magnesium aluminate, or a strontium compound such as strontium titanate. Such supports provide significantly higher selectivity to the desired epoxide than would be expected from the performance of related materials. Propylene oxide selectivity may be further enhanced through the introduction of nitrogen oxide species such as NO, alkyl halides such as ethyl chloride, and carbon dioxide into the oxygen-containing gas.Type: GrantFiled: March 10, 1998Date of Patent: July 4, 2000Assignee: ARCO Chemical Technology, L.P.Inventors: Andrew P. Kahn, Anne M. Gaffney, Rangasamy Pitchai
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Patent number: 5973171Abstract: An integrated process is provided for the production of propylene oxide from propane wherein propane is dehydrogenated to propylene and hydrogen and the resulting propylene, propane, and hydrogen mixture together with added oxygen is reacted over a palladium on titanium silicilite catalyst to form propylene oxide, the molar ratio of oxygen to hydrogen in the reaction feed being at least about 2/1.Type: GrantFiled: October 7, 1998Date of Patent: October 26, 1999Assignee: ARCO Chemical Technology, LPInventors: Robert N. Cochran, John C. Jubin, Jr., Mark A. Liepa, Robert Nedwick, Rangasamy Pitchai, W. Wayne Wentzheimer
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Patent number: 5874652Abstract: A process for hydrogenating aqueous mixtures of 4-hydroxybutanal and 3-hydroxy-2-methylpropanal is disclosed. The process uses a metallic Pt--Ru catalyst supported on .gamma.-alumina. The process gives improved yields of 2-methyl-1,3-propanediol while minimizing the formation of unwanted by-products such as isobutyl alcohol and tetrahydrofuran.Type: GrantFiled: October 18, 1993Date of Patent: February 23, 1999Assignee: Arco Chemical Technology, L.P.Inventors: Rangasamy Pitchai, Thomas S. Zak
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Patent number: 5770746Abstract: A propylene epoxidation process wherein a supported silver catalyst is utilized may be operated at high efficiency even in the absence of any organic chloride in the feedstream, provided the catalyst is first contacted at an elevated temperature with a treatment stream comprised of an organic chloride and molecular oxygen.Type: GrantFiled: June 23, 1997Date of Patent: June 23, 1998Assignee: Arco Chemical Technology, L.P.Inventors: Bernard Cooker, Anne M. Gaffney, Jennifer D. Jewson, Andrew P. Kahn, Rangasamy Pitchai
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Patent number: 5763630Abstract: Propylene is oxidized to propylene oxide in the vapor phase using an oxygen-containing gas and a supported silver catalyst comprising silver and a support comprised in whole or in substantial part of certain alkaline earth metal compounds. The alkaline earth metal compound may, for example, be a calcium compound such as calcium titanate, tribasic calcium phosphate, calcium molybdate, or calcium fluoride, a magnesium compound such as magnesium aluminate, or a strontium compound such as strontium titanate. Such supports provide significantly higher selectivity to the desired epoxide than would be expected from the performance of related materials. Propylene oxide selectivity may be further enhanced through the introduction of nitrogen oxide species such as NO, alkyl halides such as ethyl chloride, and carbon dioxide into the oxygen-containing gas.Type: GrantFiled: March 18, 1996Date of Patent: June 9, 1998Assignee: ARCO Chemical Technology, L.P.Inventors: Andrew P. Kahn, Anne M. Gaffney, Rangasamy Pitchai
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Patent number: 5703254Abstract: Propylene is oxidized to propylene oxide in the vapor phase using oxygen and a supported catalyst comprising silver, gold, a potassium promoter such as potassium nitrate or potassium carbonate and a support comprised in whole or in substantial part of an alkaline earth metal carbonate.Type: GrantFiled: October 2, 1996Date of Patent: December 30, 1997Assignee: Arco Chemical Technology, L.P.Inventors: Anne M. Gaffney, Andrew P. Kahn, Rangasamy Pitchai
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Patent number: 5698719Abstract: Oxirane compounds are formed by vapor phase catalytic molecular oxygen oxidation of a C.sub.3 -C.sub.10 olefin using a silver catalyst, and the selectivity to the oxirane product is enhanced by preconditioning the catalyst by contact with the olefin at elevated temperature in the absence of oxygen; oxygen is periodically pulsed to the reaction.Type: GrantFiled: October 11, 1996Date of Patent: December 16, 1997Assignee: Arco Chemical Tehnology, L.P.Inventors: Anne M. Gaffney, C. Andrew Jones, Rangasamy Pitchai, Andrew P. Kahn
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Patent number: 5686380Abstract: Propylene is converted to propylene oxide in a vapor phase oxidation process employing a silver catalyst supported on an alkaline earth metal carbonate and containing both a potassium salt such as potassium nitrate and a molybdenum promoter. The potassium salt and the molybdenum promoter may be simultaneously supplied by the use of a potassium salt of a molybdenum oxyanion. The efficiency of the process is greatly enhanced through the simultaneous inclusion of carbon dioxide and an organic halide in the feedstream. The feedstream need not contain a nitrogen oxide species such as NO to attain high propylene oxide selectivity.Type: GrantFiled: October 28, 1996Date of Patent: November 11, 1997Assignee: ARCO Chemical Technology, L.P.Inventors: Rangasamy Pitchai, Andrew P. Kahn, Anne M. Gaffney
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Patent number: 5625084Abstract: Propylene is converted to propylene oxide in a vapor phase oxidation process employing a silver catalyst supported on an alkaline earth metal carbonate and containing both a potassium salt such as potassium nitrate and a molybdenum promoter. The potassium salt and the molybdenum promoter may be simultaneously supplied by the use of a potassium salt of a molybdenum oxyanion. The efficiency of the process is greatly enhanced through the simultaneous inclusion of carbon dioxide and an organic halide in the feedstream. The feedstream need not contain a nitrogen oxide species such as NO to attain high propylene oxide selectivity.Type: GrantFiled: January 31, 1996Date of Patent: April 29, 1997Assignee: ARCO Chemical Technology, L.P.Inventors: Rangasamy Pitchai, Andrew P. Kahn, Anne M. Gaffney
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Patent number: 5319114Abstract: Olefins are selectively converted to epoxides by reacting with an organic hydroperoxide in the presence of a heterogeneous catalyst comprised of a carbon molecular sieve containing a Group IVA, VA, VIA, or VIIA transition metal such as molybdenum.Type: GrantFiled: September 23, 1993Date of Patent: June 7, 1994Assignee: Arco Chemical Technology, L. P.Inventors: Anne M. Gaffney, Manish K. Nandi, Rangasamy Pitchai, Yuan-Zhang Han
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Patent number: 5276210Abstract: An improved allyl alcohol hydroformylation process and catalyst are disclosed. The process uses a catalyst system comprising a Group VIII metal carbonyl complex catalyst, a trisubstituted phosphine, a neutral Group VIII(a) metal complex cocatalyst, and optionally, a diphosphinoalkane. The process uniquely gives an enhanced linear:branched aldehyde product ratio.Type: GrantFiled: March 29, 1993Date of Patent: January 4, 1994Assignee: ARCO Chemical Technology, L.P.Inventors: Rangasamy Pitchai, Anne M. Gaffney, Manish K. Nandi, Yuan-Zhang Han
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Patent number: 5233093Abstract: An improved allyl alcohol hydroformylation process and catalyst are disclosed. The process uses a catalyst system comprising a Group VIII metal carbonyl complex catalyst, a trisubstituted phosphine, a neutral Group VIII(a) metal complex cocatalyst, and optionally, a diphosphinoalkane. The process uniquely gives an enhanced linear:branched aldehyde product ratio.Type: GrantFiled: July 20, 1992Date of Patent: August 3, 1993Assignee: ARCO Chemical Technology, L.P.Inventors: Rangasamy Pitchai, Anne M. Gaffney, Manish K. Nandi, Yuan-Zhang Han
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Patent number: 5221464Abstract: Supports for catalytic reforming catalysts are prepared by doping ZrO.sub.2 with tantalum. The catalyst may contain a Group VII or Group VIII metal and/or an acidic component.Type: GrantFiled: August 12, 1991Date of Patent: June 22, 1993Assignee: Sun Company, Inc. (R&M)Inventors: Vincent A. Durante, Aristides Macris, Rangasamy Pitchai, Xenophon E. Verykios
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Patent number: 5208194Abstract: A process for recovering a Group VIII metal from an organic solution is disclosed. The organic solution is contacted with an acidic ion exchange resin that has sulfonic acid active groups. The invention provides an effective and economical way to recover valuable transition metals from dilute organic solutions.Type: GrantFiled: February 25, 1992Date of Patent: May 4, 1993Assignee: Arco Chemical Technology, L.P.Inventors: Rangasamy Pitchai, Thomas S. Zak, Kurt E. Soring
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Patent number: 5208385Abstract: A process for producing tetrahydrofuran polymers having a narrow molecular weight distribution is disclosed. Tetrahydrofuran is polymerized in the presence of a carboxylic acid anhydride and amorphous silica-alumina. The process overcomes the need for costly post-treatment techniques such as distillation and selective solvent extraction.Type: GrantFiled: February 19, 1992Date of Patent: May 4, 1993Assignee: Arco Chemical Technology, L.P.Inventors: Andrew P. Kahn, Robert G. Gastinger, Rangasamy Pitchai
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Patent number: 5166370Abstract: A process for producing tetrahydrofuran, 1,4-butanediol, and 2-methyl-1,3,-propanediol is disclosed. A mixture containing 4-hydroxybutanal and 3-hydroxy-2-methylpropanal is hydrogenated in the presence of a transition metal supported on a weakly acidic ion-exchange resin or zeolite-type material to give tetrahydrofuran as the major product, and 1,4-butanediol and 2-methyl-1,3-propanediol as minor products. High yields of 2-methyl-1,3-propanediol can be obtained.Type: GrantFiled: April 12, 1991Date of Patent: November 24, 1992Assignee: Arco Chemical Technology, L.P.Inventors: Frank J. Liotta, Jr., Haven S. Kesling, Jr., Rangasamy Pitchai