Patents by Inventor Clarence D. Chang

Clarence D. Chang 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).

  • Propylene oligomerization over silica modified zeolites
    Patent number: 5057640
    Abstract: There is provided a process for oligomerizing propylene by contacting propylene with silica modified zeolites. The modification of the zeolite with silica results in a product which is enriched in hydrocarbons falling within the boiling range of jet fuel (330.degree.-480.degree. F.) and diesel fuel (480.degree.-650.degree. F.). The zeolite may be ZSM-5, which may be modified by sorbing methylhydrogensilicone into the pores of the zeolite followed by calcination to convert the sorbed methylhydrogensilicone into amorphous silica.
    Type: Grant
    Filed: January 2, 1991
    Date of Patent: October 15, 1991
    Assignee: Mobil Oil Corp.
    Inventors: Clarence D. Chang, Paul G. Rodewald
  • Modified crystalline aluminosilicate zeolite catalyst and its use in the production of lubes of high viscosity index
    Patent number: 5043307
    Abstract: The present invention provides a process for modifying a crystalline aluminosilicate zeolite having a Constraint Index of from about to about 12 which comprises:a) steaming the as synthesized crystalline aluminosilicate zeolite containing organic template material to decompose at least a portion of said template material and to extract zeolitic aluminum; and,b) contacting the zeolite resulting from step (a) in the ammonium, alkali metal or hydrogen form with a dealuminizing agent which forms a water-soluble complex with aluminum to remove a further quantity of zeolitic aluminum therefrom.
    Type: Grant
    Filed: September 5, 1989
    Date of Patent: August 27, 1991
    Assignee: Mobil Oil Corp.
    Inventors: Emmerson Bowes, Clarence D. Chang, Scott Han, David S. Shihabi
  • Hydrocarbon conversion process including acidic zeolite reactivation
    Patent number: 5001094
    Abstract: A spent acidic zeolite catalyst, e.g., ZSM-5 obtained from a hydrocarbon conversion process such as a catalytic dewaxing operation, is reactivated by contacting the spent catalyst with aqueous alkali metal carbonate and/or alkaline earth metal carbonate.
    Type: Grant
    Filed: December 12, 1988
    Date of Patent: March 19, 1991
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Cynthia T. W. Chu
  • Process for reducing the durene content of effluent resulting from the catalytic conversion of C.sub.1 -C.sub.4 oxygenates to gasoline
    Patent number: 4973784
    Abstract: A reduction in the durene content of an effluent resulting from the zeolite-catalyzed conversion of a C.sub.1 -C.sub.4 oxygenate such as methanol to gasoline is disclosed wherein either the total effluent from said conversion or a bottoms fraction thereof containing durene is contacted with a particular zeolite catalyst to convert said durene to other products.
    Type: Grant
    Filed: December 13, 1989
    Date of Patent: November 27, 1990
    Assignee: Mobil Oil Corp.
    Inventors: Scott Han, Clarence D. Chang
  • Activation of zeolites
    Patent number: 4943545
    Abstract: Zeolitic catalysts containing framework displaced aluminum, e.g., steamed or spent catalysts, are activated by contact with aqueous fluoride solution under mild conditions. The treatment can enhance catalytic activity, ion-exchange capacity and crystallinity by replacing aluminum in the zeolitic framework.
    Type: Grant
    Filed: October 14, 1988
    Date of Patent: July 24, 1990
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Scott Han, Bruce P. Pelrine
  • Method for hydrocarbon dewaxing utilizing a reactivated spent MTG zeolite catalyst
    Patent number: 4919790
    Abstract: A method for hydrocarbon dewaxing which utilizes a reactivated acidic zeolite catalyst deactivated from MTG processing is disclosed. The deactivated MTG catalyst is contacted with a reactivation-effective amount of an alkali metal carbonate and/or an alkaline earth metal carbonate to reactivate the catalyst. The catalyst is, thereafter, converted to the catalytically active form. The catalyst is then steamed at a temperature and for a time period sufficient to reduce its alpha value to a level which is substantially equal to that of a fresh hydrocarbon dewaxing acidic zeolite catalyst. The reactivated catalyst is than used for catalyzing hydrocarbon dewaxing processes.
    Type: Grant
    Filed: October 31, 1988
    Date of Patent: April 24, 1990
    Assignee: Mobil Oil Corporation
    Inventors: Robert P. L. Absil, Clarence D. Chang, Cynthia T-W. Chu, Donald J. Klocke
  • Ammonium activation of zeolites in the presence of gaseous ammonia
    Patent number: 4912275
    Abstract: Alumina-composited zeolite catalysts are activated by contact with an aqueous ammonium solution under ammonia gas pressure such that a pH of at least about 8 is maintained in the solution. The treated zeolite may thereafter be calcined without prior ammonium-exhange to provide the zeolite in the hydrogen form. Catalysts which are activated in this manner are useful for converting alcohols and/or ethers to hydrocarbons including aromatics.
    Type: Grant
    Filed: February 15, 1989
    Date of Patent: March 27, 1990
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Cynthia T-W. Chu, Carol S. Lee
  • Active amorphous mixed oxides
    Patent number: 4902663
    Abstract: A method for preparing an amorphous mixed oxide composition of enhanced catalytic activity is provided which involves extruding a mixture of silica with one or more other oxides, e.g. titania, gallia, alumina, etc., treating the extrudate with a basic aqueous alkali and/or alkaline earth solution and then treating the extrudate with an ammonium exchange solution.
    Type: Grant
    Filed: October 28, 1987
    Date of Patent: February 20, 1990
    Assignee: Mobil Oil Corp.
    Inventors: Clarence D. Chang, Cynthia T-W. Chu
  • Modified crystalline aluminosilicate zeolite catalyst and its use in the production of lubes of high viscosity index
    Patent number: 4876411
    Abstract: The present invention provides a process for modifying a crystalline aluminosilicate zeolite having a Constraint Index of from about to about 12 which comprises:(a) steaming the as synthesized crytalline aluminosilicate zeolite containing organic template material to decompose at least a portion of said template material and to extract zeolitic aluminum; and,(b) contacting the zeolite resulting from step (a) in the ammonium, alkali metal or hydrogen form with a dealuminizing agent which forms a water-soluble complex with aluminum to remove a further quantity of zeolitic aluminum therefrom wherein said treated catalyst is employed in the making of lube oil from olefins.
    Type: Grant
    Filed: March 19, 1987
    Date of Patent: October 24, 1989
    Assignee: Mobil Oil Corporation
    Inventors: Emmerson Bowes, Clarence D. Chang, Scott Han, David S. Shihabi
  • Zeolite modifications
    Patent number: 4876228
    Abstract: A method is disclosed for modifying an aluminosilicate-containing inorganic solid having a predetermined ion exchange capacity and containing an extractable silica by contacting, in the absence of added organic nitrogen or organic phosphorous compound and added activating metal oxide, the porous solid with liquid water at a pH of at least 6, at a temperature of up to 370.degree. C. for about 1 to 100 hours, and recovering a crystalline solid having an ion exchange capacity greater than the starting inorganic solid.
    Type: Grant
    Filed: February 25, 1988
    Date of Patent: October 24, 1989
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Cynthia T-W Chu, Pochen Chu, Ralph M. Dessau, William E. Garwood, Guenter H. Kuehl, Joseph N. Miale, David S. Shihabi
  • Ammonium activation of zeolites in the presence of gaseous ammonia
    Patent number: 4871702
    Abstract: Alumina-composited zeolite catalysts are activated by contact with an aqueous ammonium solution under ammonia gas pressure such that a pH of at least about 10 is maintained in the solution. The treated zeolite may thereafter be calcined without prior ammonium-exchange to provide the zeolite in the hydrogen form.
    Type: Grant
    Filed: September 19, 1988
    Date of Patent: October 3, 1989
    Assignee: Mobil Oil Corp.
    Inventors: Clarence D. Chang, Cynthia T-W. Chu, Carol S. Lee, Randall D. Partridge
  • Production of lactones and omega-hydroxycarboxylic acids
    Patent number: 4870192
    Abstract: This invention provides process embodiments for shape-selective oxidation of cyclic ketones to lactone and/or omega-hydroxycarboxylic acid products in the presence of a zeolite catalyst composition such as ZSM-5 or zeolite Beta.Cyclohexanone can be converted to epsilon-caprolactone or 6-hydroxycaproic acid as a main product under selected conditions.
    Type: Grant
    Filed: October 14, 1986
    Date of Patent: September 26, 1989
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Stuart D. Hellring
  • Process for making alkyl pyrazines
    Patent number: 4855431
    Abstract: The invention deals with a process for making a pyrazine from an aminoalkanol by passing it over a crystalline aluminosilicate zeolite having a silica to alumina ratio of at least 12 and a constraint index of 1 to 12 under conditions to dehydrate, dehydrogenate and cyclize it.
    Type: Grant
    Filed: January 13, 1983
    Date of Patent: August 8, 1989
    Assignee: Mobil Oil Corp.
    Inventors: Clarence D. Chang, Patrick D. Perkins
  • Layered divalent metal hydrogen phosphates
    Patent number: 4846853
    Abstract: Layered divalent metal hydrogen phosphate, MHPO.sub.4.nH.sub.2 O wherein M is a Group IIA or Group IIB element and n ranges from about 0 to 2, is prepared by hydrothermal treatment of an aqueous mixture containing a source of metal oxide, a source of phosphorus oxide and a source of hydrogen atoms, said aqueous mixture having an initial pH ranging between about 3 and 10.
    Type: Grant
    Filed: March 9, 1987
    Date of Patent: July 11, 1989
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Stuart D. Hellring
  • Ammonium activation of zeolites in the presence of gaseous ammonia
    Patent number: 4837398
    Abstract: Alumina-composited zeolite catalysts are activated by contact with an aqueous ammonium solution under ammonia gas pressure such that a pH of at least about 8 is maintained in the solution. The treated zeolite may thereafter be calcined without prior ammonium-exchange to provide the zeolite in the hydrogen form.
    Type: Grant
    Filed: January 4, 1988
    Date of Patent: June 6, 1989
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Cynthia T. Chu, Carol S. Lee
  • Catalytic conversion over dehydroxylated zeolite
    Patent number: 4790928
    Abstract: The acidity of a zeolite catalyst is reduced by calcination in an essentially water-free atmosphere at temperatures above 700.degree. C., preferably from 725.degree. to 800.degree. C., to reduce the alpha value to less than about 10 percent of its original value. The low acidity catalysts produced in this way may be used for conversions requiring low acidity, shape selective catalysis, including dewaxing. The calcined, low acidity catalysts exhibit improved dewaxing activity.
    Type: Grant
    Filed: February 8, 1988
    Date of Patent: December 13, 1988
    Assignee: Mobile Oil Corporation
    Inventors: Clarence D. Chang, Nai Y. Chen, Stuart D. Hellring, Ying-Yen P. Tsao, Dennis E. Walsh
  • Catalytic conversion
    Patent number: 4788370
    Abstract: A process is provided for converting feedstock comprising C.sub.2.sup.+ olefins, C.sub.2 -C.sub.7 paraffins or mixtures thereof to product comprising C.sub.5.sup.+ hydrocarbons over a catalyst comprising a siliceous zeolite prepared by the method comprising providing zeolite Beta containing boron and aluminum, treating the zeolite with silicon tetrachloride at a temperature and for a time sufficient to replace boron with silicon, and recovering the siliceous zeolite having reduced boron content but substantially preserved initial aluminum content.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: November 29, 1988
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, David S. Shihabi, Paul B. Weisz
  • Process for manufacturing olefins
    Patent number: 4788377
    Abstract: Siliceous zeolites, particularly those of the ZSM-5 type having a crystal size of less than one micron have their activity enhanced for the conversion of alcohols and ethers to olefins by steaming.
    Type: Grant
    Filed: September 21, 1987
    Date of Patent: November 29, 1988
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, Cynthia T. Chu
  • Dewaxing by isomerization
    Patent number: 4788378
    Abstract: A process is provided for dewaxing hydrocarbon feedstock by isomerizing the waxy components of the feedstock over catalyst comprising a siliceous zeolite having been prepared by the method comprising providing a boron-containing zeolite Beta, treating the zeolite with silicon tetrachloride at a temperature and for a time sufficient to replace boron with silicon, and recovering the siliceous zeolite having reduced boron content but substantially preserved initial aluminum content.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: November 29, 1988
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, David S. Shihabi, Paul B. Weisz
  • Cracking/dewaxing
    Patent number: 4784749
    Abstract: A process is provided for converting feedstock comprising hydrocarbon compounds to product comprising hydrocarbon compounds of lower molecular weight than feedstock hydrocarbon compounds over a catalyst comprising a siliceous zeolite prepared by the method comprising providing zeolite Beta containing boron and aluminum, treating the zeolite with silicon tetrachloride at a temperature and for a time sufficient to replace boron with silicon, and recovering the siliceous zeolite having reduced boron content but substantially preserved initial aluminum content. In particular embodiments, the conversion is selective cracking for waxes and the process is useful for reducing the pour point of fuel oils and lubricants.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: November 15, 1988
    Assignee: Mobil Oil Corporation
    Inventors: Clarence D. Chang, David S. Shihabi, Paul B. Weisz