Patents by Inventor Tilak Wijesekera

Tilak Wijesekera 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: 20050215834
    Abstract: A method is provided for the efficient, low cost removal of acetol from a phenol stream. The method results in removal of substantially all of the acetol from the phenol stream without the formation of substantial amounts of additional methylbenzofuran. The method also avoids the use of expensive reagents and capital intensive distillation equipment.
    Type: Application
    Filed: August 9, 2004
    Publication date: September 29, 2005
    Inventor: Tilak Wijesekera
  • Publication number: 20050215835
    Abstract: A method is provided for the efficient, low cost removal of acetol from a phenol stream. The method results in removal of substantially all of the acetol from the phenol stream without the formation of substantial amounts of additional methylbenzofuran. The method also avoids the use of expensive reagents and capital intensive distillation equipment.
    Type: Application
    Filed: September 16, 2004
    Publication date: September 29, 2005
    Inventors: Tilak Wijesekera, Manoj Bhinde
  • Patent number: 5990363
    Abstract: The invention comprises a method for the oxidation of alkanes to alcohols and for decomposition of hydroperoxides to alcohols utilizing new compositions of matter, which are metal complexes of porphyrins. Preferred complexes have hydrogen, haloalkyl or haloaryl groups in meso positions, two of the opposed meso atoms or groups being hydrogen or haloaryl, and two of the opposed meso atoms or groups being hydrogen or haloalkyl, but not all four of the meso atoms or groups being hydrogen. Other preferred complexes are ones in which all four of the meso positions are substituted with haloalkyl groups and the beta positions are substituted with halogen atoms. A new method of synthesizing porphyrinogens is also disclosed.
    Type: Grant
    Filed: December 29, 1993
    Date of Patent: November 23, 1999
    Assignee: Sun Company, Inc.
    Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
  • Patent number: 5770728
    Abstract: Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides.
    Type: Grant
    Filed: December 19, 1996
    Date of Patent: June 23, 1998
    Assignee: Sun Company, Inc. (R&M)
    Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr., Manoj V. Bhinde
  • Patent number: 5767272
    Abstract: Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides. Also disclosed is a process for the preparation of meso-halocarbyl-porphyrins which comprises contacting a halocarbyl dipyrromethane with a halocarbyl-substituted aldehyde in the presence of an acid granular solid catalyst. Also disclosed is a process for the preparation of meso-halocarbyl-porphyrins which comprises contacting a halocarbyl dipyrromethane with a halocarbyl-substituted aldehyde in the presence of an acid granular solic catalyst.
    Type: Grant
    Filed: December 19, 1996
    Date of Patent: June 16, 1998
    Assignee: Sun Company, Inc. (R&M)
    Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr., Manoj V. Bhinde
  • Patent number: 5760217
    Abstract: The invention comprises new compositions of matter, which are iron, manganese, cobalt or ruthenium complexes of porphyrins having hydrogen, haloalkyl or haloaryl groups in meso positions, two of the opposed meso atoms or groups being hydrogen or haloaryl, and two of the opposed meso atoms or groups being hydrogen or haloalkyl, but not all four of the meso atoms or groups being hydrogen. The invention also comprises new compositions of matter in which all four of the meso positions are substituted with haloalkyl groups and the beta positions are substituted with halogen atoms. A new method of synthesizing porphyrinogens is also provided.
    Type: Grant
    Filed: June 25, 1996
    Date of Patent: June 2, 1998
    Assignee: Sun Company, Inc.
    Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
  • Patent number: 5726304
    Abstract: Compounds of the formula ##STR1## and the metalated forms and salts thereof; wherein n is an integer of 1-4; andwherein each P.sub.i is independently a pyrrole residue of the formula ##STR2## wherein each R.sub.ia and R.sub.ib is independently a noninterfering substituent, andwherein each Z.sub.i is independently a covalent bond; or isa meso bridging group of the formula ##STR3## or is an N-meso bridging group of the formula.dbd.N--.revreaction.--N.dbd.; or isa CC linkage of the formula ##STR4## or is a CNCCNC linkage of the formula ##STR5## wherein each R.sub.ic, R.sub.id, R.sub.ie, R.sub.if and R.sub.ig is independently a noninterfering substituent; or isa CNC linkage of the formula--CH.dbd.N--CH.dbd..revreaction..dbd.CH--N.dbd.CH--wherein at least one Z.sub.i is said CNC linkage, are disclosed. These compounds are useful in photodynamic therapy and diagnosis. The metalated forms when the metal is paramagnetic are useful as MRI contrast agents.
    Type: Grant
    Filed: April 26, 1994
    Date of Patent: March 10, 1998
    Assignee: The University of British Columbia
    Inventors: Hang Tang, Lily Y. Xie, Tilak Wijesekera, David Dolphin, Ross W. Boyle
  • Patent number: 5723677
    Abstract: The invention comprises a method for the oxidation of alkanes to alcohols and for decomposition of hydroperoxides to alcohols utilizing new compositions of matter, which are metal complexes of porphyrins. Preferred complexes have hydrogen, haloalkyl or haloaryl groups in meso positions, two of the opposed meso atoms or groups being hydrogen or haloaryl, and two of the opposed meso atoms or groups being hydrogen or haloalkyl, but not all four of the meso atoms or groups being hydrogen. Other preferred complexes are ones in which all four of the meso positions are substituted with haloalkyl groups and the beta positions are substituted with halogen atoms. A new method of synthesizing porphyrinogens is also disclosed.
    Type: Grant
    Filed: June 27, 1996
    Date of Patent: March 3, 1998
    Assignee: Sun Company, Inc. (R&M)
    Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
  • Patent number: 5608054
    Abstract: Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides.
    Type: Grant
    Filed: March 17, 1995
    Date of Patent: March 4, 1997
    Assignee: Sun Company, Inc. (R&M)
    Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr., Manoj V. Bhinde
  • Patent number: 5599948
    Abstract: New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by recting pyrrole in either of two reaction schemes. Once such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a [2-(1-hydroxyl-1-hydro-1-halocarbyl)pyrrole], and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.
    Type: Grant
    Filed: May 2, 1996
    Date of Patent: February 4, 1997
    Assignee: Sun Company, Inc.
    Inventor: Tilak Wijesekera
  • Patent number: 5571908
    Abstract: The invention comprises new compositions of matter, which are iron, manganese, cobalt or ruthenium complexes of porphyrins having hydrogen, haloalkyl or haloaryl groups in meso positions, two of the opposed meso atoms or groups being hydrogen or haloaryl, and two of the opposed meso atoms or groups being hydrogen or haloalkyl, but not all four of the meso atoms or groups being hydrogen. The invention also comprises new compositions of matter in which all four of the meso positions are substituted with haloalkyl groups and the beta positions are substituted with halogen atoms. A new method of synthesizing porphyrinogens is also provided.The novel compositions and others made according to the process of the invention are useful as hydrocarbon conversion catalysts; for example, for the oxidation of alkanes and the decomposition of hydroperoxides.
    Type: Grant
    Filed: December 29, 1993
    Date of Patent: November 5, 1996
    Assignee: Sun Company, Inc. (R&M)
    Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
  • Patent number: 5536844
    Abstract: New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by recting pyrrole in either of two reaction schemes. Once such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a [2-(1-hydroxyl-1-hydro-1-halocarbyl)pyrrole], and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.
    Type: Grant
    Filed: November 27, 1995
    Date of Patent: July 16, 1996
    Assignee: SunCompany, Inc. (R&M)
    Inventor: Tilak Wijesekera
  • Patent number: 5512675
    Abstract: A method for synthesizing a porphocyanine having the formula: ##STR1## where each R is ethyl, comprises either: (1) treating 3,3'-4,4'-tetraethyl-5,5'-bisaminomethyl-2,2'-dipyrromethane with a 10-fold excess of DDQ or(2) treating 3,3'-4,4'-tetraethyl-5,5'-diformyl 2,2'-dipyrromethane with ammonia, followed by column chromatography purification and evaporating to dryness the eluant containing the purified product.
    Type: Grant
    Filed: June 15, 1993
    Date of Patent: April 30, 1996
    Assignee: The University of British Columbia
    Inventors: Hang Tang, Lily Xie, Tilak Wijesekera, David Dolphin
  • Patent number: 5502211
    Abstract: New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by recting pyrrole in either of two reaction schemes. Once such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a 2-(1-hydroxyl-1-hydro-1-halocarbyl)pyrrole!, and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.
    Type: Grant
    Filed: October 26, 1993
    Date of Patent: March 26, 1996
    Assignee: Sun Company, Inc. (R&M)
    Inventor: Tilak Wijesekera
  • Patent number: 5405957
    Abstract: A group of novel expanded porphyrin-like compounds, porphacyanine (Pc) and porphacyanine-like compounds, having absorption maxima in the range of 400-850 nanometers is useful in detecting and treating targeted tissues, cells and viruses. The use of the Pc of the invention permits the irradiation to comprise wavelengths other than those absorbed by blood. The Pc of the invention may also be conjugated to target-specific moieties such as immunoglobulins or fragments thereof to target specific tissues or cells for the radiation treatment. Use of these materials permits greater depth of treatment penetration and greater specificity in targeting tissues or cells. Coupled with an appropriate paramagnetic ion or radioisotope, the Pc of the invention is suitable for use in nuclear magnetic resonance imaging and radioimaging.
    Type: Grant
    Filed: October 30, 1992
    Date of Patent: April 11, 1995
    Assignee: The University of British Columbia
    Inventors: Hang Tang, Lily Xie, Tilak Wijesekera, David Dolphin
  • Patent number: 5308608
    Abstract: A group of hydro-dibenzoporphyrins prepared by di-Diels-Alder additions at the A and C rings of the appropriate divinyl porphyrins have absorption maxima in the range of 700-820 nanometers and are photosensitizing agents. These compounds are useful in treating disorders or conditions which are subject to hematoporphyrin derivative (HPD) treatment in the presence of light, or in treating biological materials generally to destroy unwanted targets such as viruses, cells and tissues. The use of the compounds of the invention permits irradiation with wavelengths other than those absorbed by blood. The compounds of the invention may also be conjugated to ligands specific for receptors or to specific immunoglobulins or fragments thereof to home to target tissues or cells for the radiation treatment. Use of these materials permits lower levels of photosensitizer to be used, thus preventing side reactions which might destroy normal tissues.
    Type: Grant
    Filed: September 4, 1992
    Date of Patent: May 3, 1994
    Assignee: University of British Columbia
    Inventors: David Dolphin, Paul Y. Hin, Tilak Wijesekera
  • Patent number: 5149708
    Abstract: A group of hydro-dibenzoporphyrins prepared by di-Diels-Alder additions at the A and C rings of the appropriate divinyl porphyrins have absorption maxima in the range of 700-820 nanometers and are photosensitizing agents. These compounds are useful in treating disorders or conditions which are subject to hematoporphyrin derivative (HPD) treatment in the presence of light, or in treating biological materials generally to destroy unwanted targets such as viruses, cells and tissues. The use of the compounds of the invention permits irradiation with wavelengths other than those absorbed by blood. The compounds of the invention may also be conjugated to ligands specific for receptors or to specific immunoglobulins or fragments thereof to home to target tissues or cells for the radiation treatment. Use of these materials permits lower levels of photosensitizer to be used, thus preventing side reactions which might destroy normal tissues.
    Type: Grant
    Filed: February 28, 1991
    Date of Patent: September 22, 1992
    Assignee: University of British Columbia
    Inventors: David Dolphin, Paul Y. Hin, Tilak Wijesekera