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).

  • Publication number: 20140044633
    Abstract: Methods and systems are provided for selective catalytic reduction of NOx with a low molecular low molecular weight hydrocarbon, e.g., propylene, as a reductant using a catalyst system including two catalysts. An exhaust stream containing an amount of NOx from a combustion operation is provided. A portion of the exhaust stream and a reductant stream including a low molecular weight hydrocarbon is introduced to a first catalytic reactor, which comprises a first catalyst including alumina loaded with silver. The NOx-reduced exhaust stream from the first catalyst is then directed to a second catalyst including zirconia loaded with at least one metal.
    Type: Application
    Filed: July 10, 2013
    Publication date: February 13, 2014
    Applicant: EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
    Inventors: Ajit B. DANDEKAR, Richard F. SOCHA, Richard L. ECKES, S. Beau WALDRUP
  • Publication number: 20140041363
    Abstract: Methods and systems are provided for selective catalytic reduction of NOx with a low molecular low molecular weight aldehyde, e.g., acetaldehyde, as a reductant using a catalyst system including two catalysts. An exhaust stream containing an amount of NO from a combustion operation is provided. A portion of the exhaust stream is introduced to a first catalyst to convert the NO to NO2. The exhaust stream from the first catalyst with NO2 and a reductant stream containing a low molecular weight aldehyde, e.g., acetaldehyde, are introduced to the second catalyst to convert the NO2 to N2. The first catalyst can be bulk Co3O4, Ru or Pt loaded on alumina; the second catalyst can be various zeolites, or zeolites loaded with potassium.
    Type: Application
    Filed: July 10, 2013
    Publication date: February 13, 2014
    Applicant: EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
    Inventors: Ajit B. DANDEKAR, Richard F. SOCHA, Richard L. ECKES, S. Beau WALDRUP, Jason M. McMULLAN
  • Publication number: 20130264246
    Abstract: Provided are high viscosity high quality Group II lube base stocks with improved properties produced by an integrated hydrocracking and dewaxing process. In one form, the Group II lube base stock includes greater than or equal to 90 wt. % saturates, and less than 10 wt. % aromatics, and has an aromatic performance ratio between 1.0 and 5.0. Also provided are lubricant formulations including the high viscosity high quality Group II lube base stock.
    Type: Application
    Filed: March 14, 2013
    Publication date: October 10, 2013
    Applicant: ExxonMobil Research and Engineering Company
    Inventors: Gretchen L. Holtzer, Ajit B. Dandekar, Charles L. Baker, Bradley R. Fingland, Bryan E. Hagee, Cathleen Yung, Frank C. Wang, Eugenio Sanchez, Rugved Prakash Pathare
  • Publication number: 20130026070
    Abstract: This invention relates to hydrocracking catalysts utilizing stabilized aggregates of small primary crystallites of zeolite Y that are clustered into larger secondary particles. At least 80% of the secondary particles may comprise at least 5 primary crystallites. The size of the primary crystallites may be at most about 0.5 micron, or at most about 0.3 micron, and the size of the secondary particles may be at least about 0.8 micron, or at least about 1.0 ?m. The silica to alumina ratio of the resulting stabilized aggregated Y zeolite may be 4:1 or more. This invention also relates to the use of such catalysts in hydrocracking processes for the conversion of heavy oils into lighter fuel products. The invention is particularly suited for the selective production of diesel range products from gas oil range feedstock materials under hydrocracking conditions.
    Type: Application
    Filed: March 6, 2012
    Publication date: January 31, 2013
    Applicant: ExxonMobil Research and Engineering Company
    Inventors: Christopher G. Oliveri, Wenyih Frank Lai, Ajit B. Dandekar, Scott J. Weigel, Jason Wu, Robert E. Kay
  • Patent number: 8263517
    Abstract: Catalysts for dewaxing of hydrocarbon feeds, particularly feeds with elevated sulfur and nitrogen levels, are provided. The dewaxing catalysts include a zeolite with a low silica to alumina ratio combined with a low surface binder, or alternatively the formulated catalyst has a high ratio of zeolite surface area to external surface area.
    Type: Grant
    Filed: December 18, 2008
    Date of Patent: September 11, 2012
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: Christine N. Elia, Mohan Kalyanaraman, Lei Zhang, Madhav Acharya, Michael A. Daage, Darden Sinclair, Jocelyn A. Kowalski, Jose G. Santiesteban, Ajit B. Dandekar
  • Patent number: 7951986
    Abstract: Disclosed herein is a process and catalyst for producing an ethylbenzene feed from a polyethylbenzene feed, comprising the step of contacting a benzene feed with a polyethylbenzene feed under at least partial liquid phase conditions in the presence of a zeolite beta catalyst having a phosphorus content in the range of 0.01 wt. % to 0.5 wt. % of said catalyst, to provide a product which comprises ethylbenzene.
    Type: Grant
    Filed: July 29, 2010
    Date of Patent: May 31, 2011
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Michael C. Clark, Jane C. Cheng, Ajit B. Dandekar
  • Patent number: 7868215
    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: November 10, 2009
    Date of Patent: January 11, 2011
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, Michael Hryniszak, David Lawrence Stern
  • Publication number: 20100298617
    Abstract: Disclosed herein is a process and catalyst for producing an ethylbenzene feed from a polyethylbenzene feed, comprising the step of contacting a benzene feed with a polyethylbenzene feed under at least partial liquid phase conditions in the presence of a zeolite beta catalyst having a phosphorus content in the range of 0.01 wt. % to 0.5 wt. % of said catalyst, to provide a product which comprises ethylbenzene.
    Type: Application
    Filed: July 29, 2010
    Publication date: November 25, 2010
    Inventors: Michael C. Clark, Jane C. Cheng, Ajit B. Dandekar
  • Patent number: 7795487
    Abstract: Disclosed herein is a process and catalyst for producing a monoalkylated aromatic compound from a polyalkylated aromatic compound, comprising the step of contacting an alkylatable aromatic compound with a polyalkylated aromatic compound under at least partial liquid phase conditions in the presence of a zeolite beta catalyst having a phosphorus content in the range of 0.001 wt. % to 10.0 wt. % of said catalyst, to provide a product which comprises a monoalkylated aromatic compound.
    Type: Grant
    Filed: February 27, 2006
    Date of Patent: September 14, 2010
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Michael C. Clark, Jane C. Cheng, Ajit B. Dandekar
  • Publication number: 20100056835
    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: November 10, 2009
    Publication date: March 4, 2010
    Inventors: Ajit B. Dandekar, Michael Hryniszak, David Lawrence Stern
  • Patent number: 7671248
    Abstract: A process for producing sec-butylbenzene comprises contacting a feed comprising benzene and ethylene under alkylation conditions with catalyst comprising (i) a molecular sieve having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom and (ii) at least one metal selected from Group 10 of the Periodic Table of Elements to produce an alkylation effluent comprising sec-butylbenzene.
    Type: Grant
    Filed: August 5, 2005
    Date of Patent: March 2, 2010
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, John P. McWilliams, Thomas Francis Degnan, Jr., Michael Hryniszak
  • Patent number: 7638668
    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: October 22, 2007
    Date of Patent: December 29, 2009
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, Michael Hryniszak, David Lawrence Stern
  • Patent number: 7569739
    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: October 17, 2007
    Date of Patent: August 4, 2009
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, John P. McWilliams, Thomas Francis Degnan, Michael Hryniszak, Donald J. Klocke, Wieslaw Jerzy Roth
  • Publication number: 20090186754
    Abstract: Catalysts for dewaxing of hydrocarbon feeds, particularly feeds with elevated sulfur and nitrogen levels, are provided. The dewaxing catalysts include a zeolite with a low silica to alumina ratio combined with a low surface binder, or alternatively the formulated catalyst has a high ratio of zeolite surface area to external surface area.
    Type: Application
    Filed: December 18, 2008
    Publication date: July 23, 2009
    Inventors: Christine Elia, Mohan Kalyanaraman, Lei Zhang, Madhav Acharya, Michael A. Daage, Darden Sinclair, Jocelyn A. Kowalski, Jose G. Santiesteban, Ajit B. Dandekar
  • Patent number: 7525002
    Abstract: A process for the production of high octane number gasoline from light refinery olefins, typically from the catalytic cracking unit, and benzene-containing aromatic streams such as reformate. A portion of the light olefins including ethylene and propylene is polymerized to form a gasoline boiling range product and another portion is used to alkylate the light aromatic stream. The alkylation step may be carried out in successive stages with an initial low temperature stage using a catalyst comprising an MWW zeolite followed by a higher temperature stage using a catalyst comprising an intermediate pore size zeolite such as ZSM-5. Using this staged approach, the alkylation may be carried out in the vapor phase. Alternatively, the alkylation may be carried out in the liquid phase using the heavier olefins (propylene, butene) dissolved into the aromatic stream by selective countercurrent extraction; a separate alkylation step using the ethylene not taken up in the extraction is carried out at a higher temperature.
    Type: Grant
    Filed: February 27, 2006
    Date of Patent: April 28, 2009
    Assignee: ExxonMobil Research and Engineering Company
    Inventors: Benjamin S. Umansky, Michael C. Clark, Ajit B. Dandekar
  • Patent number: 7498474
    Abstract: A process for the production of high octane number gasoline from light refinery olefins and benzene-containing aromatic streams such as reformate. The process achieves good utilization of both the ethylene and the propylene present in the mixed olefin feed from the unsaturated gas plant while reducing gasoline benzene levels. The light olefins including ethylene and propylene are reacted with the light aromatic stream containing benzene and other single ring aromatic compounds to form a gasoline boiling range product containing akylaromatics. The reaction is carried out with a two-catalyst system which comprises a member of the MWW family of zeolites and an intermediate pore size zeolite such as ZSM-5 using a fixed catalyst bed in both stages. Use of the two catalyst system enables the conversion of the ethylene and propylene components of the olefin feed to be converted to alkylaromatics under favorable conditions.
    Type: Grant
    Filed: February 27, 2006
    Date of Patent: March 3, 2009
    Assignee: Exxonmobil Research and Engineering Company
    Inventors: Benjamin S. Umansky, Michael C. Clark, Ajit B. Dandekar, Christine N. Elia
  • Patent number: 7399894
    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: March 24, 2005
    Date of Patent: July 15, 2008
    Assignee: ExxonMobil Chemical Patents Inc.
    Inventors: Ajit B. Dandekar, Michael N M N Hryniszak, David Lawrence Stern
  • Publication number: 20080167508
    Abstract: Disclosed herein is a process and catalyst for producing a monoalkylated aromatic compound from a polyalkylated aromatic compound, comprising the step of contacting an alkylatable aromatic compound with a polyalkylated aromatic compound under at least partial liquid phase conditions in the presence of a zeolite beta catalyst having a phosphorus content in the range of 0.001 wt. % to 10.0 wt. % of said catalyst, to provide a product which comprises a monoalkylated aromatic compound.
    Type: Application
    Filed: February 27, 2006
    Publication date: July 10, 2008
    Inventors: Michael C. Clark, Jane C. Cheng, Ajit B. Dandekar
  • Publication number: 20080154082
    Abstract: A process for producing sec-butylbenzene comprises contacting a feed comprising benzene and ethylene under alkylation conditions with catalyst comprising (i) a molecular sieve having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom and (ii) at least one metal selected from Group 10 of the Periodic Table of Elements to produce an alkylation effluent comprising sec-butylbenzene.
    Type: Application
    Filed: August 5, 2005
    Publication date: June 26, 2008
    Applicant: EXXONMOBIL CHEMICAL PATENTS INC.
    Inventors: Ajit B. Dandekar, John P. McWilliams, Thomas Francis Degnan, Michael Hryniszak
  • Publication number: 20080029435
    Abstract: A method of rejuvenating a deactivated molecular sieve catalyst, deactivated by use in an olefin oligomerization or aromatics alkylation process, which method comprises contacting the deactivated catalyst with a stream of rejuvenation gas comprising a hydrocarbon product fraction from the process at an elevated temperature and pressure for a time sufficient to effect an increase in catalytic activity of the deactivated catalyst.
    Type: Application
    Filed: June 19, 2007
    Publication date: February 7, 2008
    Applicant: ExxonMobil Research and Engineering Company
    Inventors: Benjamin S. Umansky, Ajit B. Dandekar, Tomas R. Melli, Amanda K. Miller, Ronald D. McGihon