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).
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Publication number: 20050215835Abstract: 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: ApplicationFiled: September 16, 2004Publication date: September 29, 2005Inventors: Tilak Wijesekera, Manoj Bhinde
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Publication number: 20050215834Abstract: 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: ApplicationFiled: August 9, 2004Publication date: September 29, 2005Inventor: Tilak Wijesekera
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Patent number: 5990363Abstract: 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: GrantFiled: December 29, 1993Date of Patent: November 23, 1999Assignee: Sun Company, Inc.Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
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Patent number: 5770728Abstract: 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: GrantFiled: December 19, 1996Date of Patent: June 23, 1998Assignee: Sun Company, Inc. (R&M)Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr., Manoj V. Bhinde
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Patent number: 5767272Abstract: 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: GrantFiled: December 19, 1996Date of Patent: June 16, 1998Assignee: Sun Company, Inc. (R&M)Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr., Manoj V. Bhinde
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Patent number: 5760217Abstract: 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: GrantFiled: June 25, 1996Date of Patent: June 2, 1998Assignee: Sun Company, Inc.Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
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Patent number: 5726304Abstract: 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: GrantFiled: April 26, 1994Date of Patent: March 10, 1998Assignee: The University of British ColumbiaInventors: Hang Tang, Lily Y. Xie, Tilak Wijesekera, David Dolphin, Ross W. Boyle
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Patent number: 5723677Abstract: 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: GrantFiled: June 27, 1996Date of Patent: March 3, 1998Assignee: Sun Company, Inc. (R&M)Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
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Patent number: 5608054Abstract: 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: GrantFiled: March 17, 1995Date of Patent: March 4, 1997Assignee: Sun Company, Inc. (R&M)Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr., Manoj V. Bhinde
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Patent number: 5599948Abstract: 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: GrantFiled: May 2, 1996Date of Patent: February 4, 1997Assignee: Sun Company, Inc.Inventor: Tilak Wijesekera
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Patent number: 5571908Abstract: 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: GrantFiled: December 29, 1993Date of Patent: November 5, 1996Assignee: Sun Company, Inc. (R&M)Inventors: Tilak Wijesekera, James E. Lyons, Paul E. Ellis, Jr.
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Patent number: 5536844Abstract: 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: GrantFiled: November 27, 1995Date of Patent: July 16, 1996Assignee: SunCompany, Inc. (R&M)Inventor: Tilak Wijesekera
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Patent number: 5512675Abstract: 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: GrantFiled: June 15, 1993Date of Patent: April 30, 1996Assignee: The University of British ColumbiaInventors: Hang Tang, Lily Xie, Tilak Wijesekera, David Dolphin
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Patent number: 5502211Abstract: 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: GrantFiled: October 26, 1993Date of Patent: March 26, 1996Assignee: Sun Company, Inc. (R&M)Inventor: Tilak Wijesekera
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Patent number: 5405957Abstract: 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: GrantFiled: October 30, 1992Date of Patent: April 11, 1995Assignee: The University of British ColumbiaInventors: Hang Tang, Lily Xie, Tilak Wijesekera, David Dolphin
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Patent number: 5308608Abstract: 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: GrantFiled: September 4, 1992Date of Patent: May 3, 1994Assignee: University of British ColumbiaInventors: David Dolphin, Paul Y. Hin, Tilak Wijesekera
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Patent number: 5149708Abstract: 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: GrantFiled: February 28, 1991Date of Patent: September 22, 1992Assignee: University of British ColumbiaInventors: David Dolphin, Paul Y. Hin, Tilak Wijesekera