Patents by Inventor Ajit B. Dandekar

Ajit B. Dandekar 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: 7297829
    Abstract: The present invention provides a process for producing an alkylaromatic compound comprising the step of contacting an alkylatable aromatic compound with an alkylating agent under alkylation conditions in the presence of a alkylation catalyst comprising phosphorus and a porous crystalline inorganic oxide material having an X-ray diffraction pattern including the d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom.
    Type: Grant
    Filed: May 13, 2005
    Date of Patent: November 20, 2007
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, John P. McWilliams, Thomas Francis Degnan, Michael Hryniszak, Donald J. Klocke, Wieslaw Jerzy Roth
  • Patent number: 7038100
    Abstract: The present invention provides a process for producing an alkylaromatic compound comprising the step of contacting an alkylatable aromatic compound with an alkylating agent under alkylation conditions in the presence of a alkylation catalyst comprising phosphorus and a porous crystalline inorganic oxide material having an X-ray diffraction pattern including the d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom.
    Type: Grant
    Filed: April 30, 2001
    Date of Patent: May 2, 2006
    Assignee: ExxonMobil Chemical Patents, Inc.
    Inventors: Ajit B. Dandekar, John P. McWilliams, Thomas Francis Degnan, Michael Hryniszak, Donald J. Klocke, Wieslaw Jerzy Roth
  • Patent number: 6911568
    Abstract: A process for alkylating an alkylatable aromatic compound is disclosed, in which the process includes: (a) contacting the alkylatable aromatic compound and an alkylating agent with an alkylation catalyst under alkylation conditions; and (b) when said alkylation catalyst has become at least partially deactivated, contacting said alkylation catalyst with a C1-C8 hydrocarbon under alkylation catalyst reactivation conditions. The process provides comparable rejuvenation of catalyst activity as air rengenaration with minimal or no increase in amounts of undesirable byproducts such as polypropylbenzenes in the case of benzene alkylation with propylene.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: June 28, 2005
    Assignee: ExxonMobil Oil Corporation
    Inventors: Ajit B. Dandekar, John P. McWilliams, C. Morris Smith, Michael A. Better, Wei-Ping Tai
  • Patent number: 6909026
    Abstract: The catalyst becomes at least partially deactivated by sorbing catalyst poisons present in the feed during a process for alkylating aromatics by contacting a feed containing benzene, toluene, xylenes, alkylbenzenes, naphthalene or substituted naphthalenes under liquid phase alkylating conditions with C2-C16 olefins in the presence of MCM-22, MCM-36, MCM-49, MCM-56, ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-48, ZSM-50, ZSM-4, ZSM-18, ZSM-20, Zeolite X, Zeolite Y, USY, mordenite or offretite to provide an alkylated aromatic product. The at least partially deactivated catalyst can be treated in situ by contacting with at least one polar compound having a dipole moment of at least 0.05 Debyes and selected from the group consisting of acetic acid, formic acid, water, and carbon monoxide, under conditions of temperature and pressure employed in the liquid phase alkylating conditions which are sufficient to at least partially desorb the catalyst poison from the catalyst.
    Type: Grant
    Filed: December 13, 2002
    Date of Patent: June 21, 2005
    Assignee: ExxonMobil Oil Corporation
    Inventors: Ajit B. Dandekar, Thomas Francis Degnan, John P. McWilliams, Chaya R. Venkat
  • Patent number: 6888037
    Abstract: A process for producing cumene is provided which comprises the step of contacting benzene and propylene under at least partial liquid phase alkylating conditions with a particulate molecular sieve alkylation catalyst, wherein the particles of said alkylation catalyst have a surface to volume ratio of about 80 to less than 200 inch?1.
    Type: Grant
    Filed: December 13, 2002
    Date of Patent: May 3, 2005
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, Michael Hryniszak, David Lawrence Stern
  • Patent number: 6878654
    Abstract: The present invention provides a process for regenerating a spent aromatics alkylation or transalkylation catalyst comprising a molecular sieve by contacting the spent catalyst with an oxygen-containing gas at a temperature of about 120 to about 600° C. and then contacting the catalyst with an aqueous medium, such as an ammonium nitrate solution, an ammonium carbonate solution or an acid solution.
    Type: Grant
    Filed: September 13, 2002
    Date of Patent: April 12, 2005
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, Michael Hryniszak, Jeffrey S. Beck, David L. Stern, Kathleen M. Keville
  • Patent number: 6781025
    Abstract: The present invention provides a process for regenerating a spent aromatics alkylation or transalkylation catalyst comprising a molecular sieve by contacting the spent catalyst with an oxygen-containing gas at a temperature of about 120 to about 600° C. and then contacting the catalyst with an aqueous medium, such as an ammonium nitrate solution, an ammonium carbonate solution or an acetic acid solution.
    Type: Grant
    Filed: July 11, 2001
    Date of Patent: August 24, 2004
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B Dandekar, Michael Hryniszak, David Lawrence Stern, Jeffrey Scott Beck
  • Publication number: 20030125592
    Abstract: 1.
    Type: Application
    Filed: December 13, 2002
    Publication date: July 3, 2003
    Inventors: Ajit B. Dandekar, Thomas Francis Degnan, John P. McWilliams, Chaya R. Venkat
  • Publication number: 20030092949
    Abstract: A process for producing cumene is provided which comprises the step of contacting benzene and propylene under at least partial liquid phase alkylating conditions with a particulate molecular sieve alkylation catalyst, wherein the particles of said alkylation catalyst have a surface to volume ratio of about 80 to less than 200 inch−1.
    Type: Application
    Filed: December 13, 2002
    Publication date: May 15, 2003
    Inventors: Ajit B. Dandekar, Michael Hryniszak, David Lawrence Stern
  • Publication number: 20030050521
    Abstract: The present invention provides a process for regenerating a spent aromatics alkylation or transalkylation catalyst comprising a molecular sieve by contacting the spent catalyst with an oxygen-containing gas at a temperature of about 120 to about 600° C. and then contacting the catalyst with an aqueous medium, such as an ammonium nitrate solution, an ammonium carbonate solution or an acid solution.
    Type: Application
    Filed: September 13, 2002
    Publication date: March 13, 2003
    Inventors: Ajit B. Dandekar, Michael Hryniszak, Jeffrey S. Beck, David L. Stern, Kathleen M. Keville
  • Patent number: 6525234
    Abstract: A process for alkylating aromatics comprises: i) contacting a feed containing alkylatable aromatic, e.g., benzene, under liquid phase alkylating conditions with an alkylating agent, e.g., ethylene, in the presence of an alkylation catalyst comprising a porous crystalline material, e.g., MCM-22, to provide an alkylated aromatic product during which contacting said catalyst becomes at least partially deactivated by sorbing catalyst poisons present in said feed; ii) treating said at least partially deactivated catalyst in situ by contacting with at least one polar compound, e.g., water or acetic acid, having a dipole moment of at least 0.05 Debyes under conditions of temperature and pressure employed in said liquid phase alkylating conditions which are sufficient to at least partially desorb said catalyst poison from said catalyst; and iii) collecting said alkylated aromatic product.
    Type: Grant
    Filed: November 21, 2000
    Date of Patent: February 25, 2003
    Assignee: ExxonMobil Oil Corporation
    Inventors: Ajit B. Dandekar, Thomas Francis Degnan, John P. McWilliams, Chaya R. Venkat
  • Publication number: 20030028060
    Abstract: The present invention provides a process for producing an alkylaromatic compound comprising the step of contacting an alkylatable aromatic compound with an alkylating agent under alkylation conditions in the presence of a alkylation catalyst comprising phosphorus and a porous crystalline inorganic oxide material having an X-ray diffraction pattern including the d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom.
    Type: Application
    Filed: April 30, 2001
    Publication date: February 6, 2003
    Inventors: Ajit B. Dandekar, John P. McWilliams, Thomas Francis Degnan, Michael Hryniszak, Donald J. Klocke, Wieslaw Jerzy Roth
  • Patent number: 6506953
    Abstract: There is described a process the hydroalkylation of an aromatic hydrocarbon, particularly benzene, to produce a cycloalkyl-substituted aromatic compound, particularly cyclohexylbenzene, comprising the step of contacting the aromatic hydrocarbon with hydrogen in the presence of a catalyst comprising MCM-68 and at least one metal having hydrogenation activity.
    Type: Grant
    Filed: January 24, 2000
    Date of Patent: January 14, 2003
    Assignee: ExxonMobil Oil Corporation
    Inventors: Jane Chi-Ya Cheng, Ajit B. Dandekar, Michael Alan Steckel, Hye Kyung Cho Timken
  • Publication number: 20020042548
    Abstract: A process for producing cumene is provided which comprises the step of contacting benzene and propylene under at least partial liquid phase alkylating conditions with a particulate molecular sieve alkylation catalyst, wherein the particles of said alkylation catalyst have a surface to volume ratio of about 80 to less than 200 inch−1.
    Type: Application
    Filed: July 11, 2001
    Publication date: April 11, 2002
    Inventors: Ajit B. Dandekar, Michael Hryniszak, David Lawrence Stern
  • Publication number: 20020038067
    Abstract: The present invention provides a process for regenerating a spent aromatics alkylation or transalkylation catalyst comprising a molecular sieve by contacting the spent catalyst with an oxygen-containing gas at a temperature of about 120 to about 600° C. and then contacting the catalyst with an aqueous medium, such as an ammonium nitrate solution, an ammonium carbonate solution or an acetic acid solution.
    Type: Application
    Filed: July 11, 2001
    Publication date: March 28, 2002
    Inventors: Ajit B. Dandekar, Michael Hryniszak, David Lawrence Stern, Jeffrey Scott Beck