Patents by Inventor K. Pushpananda A. Senaratne
K. Pushpananda A. Senaratne 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: 6020284Abstract: Gaseous anhydrous hydrogen chloride is introduced into an aqueous solution of zinc chloride under conditions effective to produce a more efficient Lucas reagent than a Lucas reagent made by mixing solid, anhydrous zinc chloride with 38% hydrochloric acid. For example, the reaction rate of such Lucas reagent with levo-menthol is much faster and requires a much shorter reaction period than Lucas reagent formed in the conventional manner from anhydrous, solid zinc chloride and concentrated (38%) hydrochloric acid. Also, the conversion to levo-menthyl chloride was higher when using Lucas reagent formed using gaseous anhydrous hydrogen chloride and aqueous zinc chloride solution. Also, Lucas reagent made in this manner is highly amenable to recycling, and requires only addition thereto of hydrogen chloride to replenish the catalyst for an ensuing run.Type: GrantFiled: September 9, 1998Date of Patent: February 1, 2000Assignee: Albemarle CorporationInventors: K. Pushpananda A. Senaratne, Felix M. Orihuela, Arcelio J. Malcolm
-
Patent number: 5994587Abstract: A process for the purification of crude neomenthyldiphenylphosphine, the process comprising crystallizing the crude neomenthyldiphenylphosphine using a solvent consisting essentially of methanol. The process provides for the unexpectedly efficient production of neomenthyldiphenylphosphine having purities of at least 97 mole percent, and more preferably at least about 99 mole percent. Another embodiment of the invention is neomenthyldiphenylphosphine having a purity of at least 97 mole percent produced by crystallizing crude neomenthyldiphenylphosphine having a purity of less than 97 mole percent using a solvent consisting essentially of methanol.Type: GrantFiled: May 26, 1998Date of Patent: November 30, 1999Assignee: Albemarle CorporationInventors: Tse-Chong Wu, K. Pushpananda A. Senaratne
-
Patent number: 5902906Abstract: A mixture formed from one or more alkyl disulfides, benzene, and at least about 1.5 equivalents of Lewis acid catalyst is heated to form alkanethiobenzene. Reaction in a mixture formed from excess benzene, dimethyldisulfide (DMDS) and AlCl.sub.3 in which the mole ratio of AlCl.sub.3 to DMDS was 2:1 was complete in 2 hours and afforded 98% conversion and 93% yield of thioanisole. In contrast, the same reaction when attempted using a 1:1 mole ratio of AlCl.sub.3 to DMDS after 6 hours achieved only 66% conversion and a thioanisole yield of only 35%. So far as is known, this is the first example of a highly efficient electrophilic aromatic substitution of the inactivated benzene ring by an alkanethio group.Type: GrantFiled: May 1, 1997Date of Patent: May 11, 1999Assignee: Albemarle CorporationInventors: K. Pushpananda A. Senaratne, Charles R. Everly, Won S. Park
-
Patent number: 5856597Abstract: Gaseous anhydrous hydrogen chloride is introduced into an aqueous solution of zinc chloride under conditions effective to produce a more efficient Lucas reagent than a Lucas reagent made by mixing solid, anhydrous zinc chloride with 38% hydrochloric acid. For example, the reaction rate of such Lucas reagent with levo-menthol is much faster and requires a much shorter reaction period than Lucas reagent formed in the conventional manner from anhydrous, solid zinc chloride and concentrated (38%) hydrochloric acid. Also, the conversion to levo-menthyl chloride was higher when using Lucas reagent formed using gaseous anhydrous hydrogen chloride and aqueous zinc chloride solution. Also, Lucas reagent made in this manner is highly amenable to recycling, and requires only addition thereto of hydrogen chloride to replenish the catalyst for an ensuing run.Type: GrantFiled: April 25, 1997Date of Patent: January 5, 1999Assignee: Albemarle CorporationInventors: K. Pushpananda A. Senaratne, Felix M. Orihuela, Arcelio J. Malcolm
-
Patent number: 5710340Abstract: Phosphines having two aryl groups and one alkyl-substituted cycloalkyl group bonded to a phosphorus atom are formed by reacting an alkali metal diarylphosphide with a monoalkyl- or polyalkyl-substituted cycloalkyl mesylate or tosylate in which an alkyl group is in the 2-position, in a liquid reaction medium in which these reactants are soluble. This process avoids complications associated with prior known process technology for producing such phosphines. The phosphines are useful as ligands for making noble metal catalysts.Type: GrantFiled: April 29, 1996Date of Patent: January 20, 1998Assignee: Albemarle CorporationInventor: K. Pushpananda A. Senaratne
-
Patent number: 5654485Abstract: By reacting certain partially sterically-hindered chloro-substituted cycloalkanes with sodium and/or potassium diarylphosphides in an ether reaction medium, not only are useful cycloalkyldiarylphosphines produced, but in addition the chloro-substituted cycloalkane does not undergo any appreciable reaction with the coproduced aryl sodium and/or aryl potassium as it is formed. Moreover, the process makes it possible to avoid or at least to greatly reduce interaction with or cleavage of cyclic ether reaction media such as tetrahydrofuran. Thus the process makes possible improvements both in yield and quality of the cycloalkyldiarylphosphite product. A two-stage process conducted in an ether reaction medium is also described. In the first stage the sodium and/or potassium diarylphosphine reactant is produced by reaction between sodium and/or potassium and triarylphosphine.Type: GrantFiled: March 25, 1996Date of Patent: August 5, 1997Assignee: Albemarle CorporationInventors: K. Pushpananda A. Senaratne, Arcelio J. Malcolm, Felix M. Orihuela, Hassan Y. Elnagar
-
Patent number: 5654486Abstract: Partially sterically-hindered cycloalkyl chlorides are reacted with lithium diarylphosphides in inert liquid hydrocarbon reaction media to form cycloalkyldiarylphosphines. Aryl lithium is coproduced. The process makes it possible to avoid, or at least substantially eliminate, the interaction with or cleavage of cyclic ether reaction media such as tetrahydrofuran, previously the solvent of choice for conducting this type of reaction. Also during the conduct of the present process the chloro-substituted cycloalkane does not undergo any appreciable reaction with the coproduced aryl lithium as it is formed. Thus improvements both in yield and quality of the cycloalkyldiarylphosphine product are made possible. A comprehensive three-step process for converting triarylphosphine to cycloalkyldiarylphosphine is also described.Type: GrantFiled: March 25, 1996Date of Patent: August 5, 1997Assignee: Albemarle CorporationInventors: K. Pushpananda A. Senaratne, Arcelio J. Malcolm, Felix M. Orihuela, Hassan Y. Elnagar
-
Patent number: 5391312Abstract: Seals contacted with lubricants, such as poly-.alpha.-olefin lubricants, are made to swell rather than shrink by the use of novel seal-swell agents which are effective even when used in amounts constituting less than 5% of the weight of the lubricant compositions. These seal-swell agents are ester oils composed of molecules corresponding to the formula ROOC--CH.sub.2 CH.sub.2 --[(ROOC)CHCH.sub.2 ].sub.m --C(COOR).sub.2 --[CH.sub.2 CH(COOR)].sub.n --CH.sub.2 CH.sub.2 COOR in which the R's represent alkyl groups of 1-30 carbons, and each of m and n represents zero or a positive integer such that the sum of m and n in a molecule is 0-30.Type: GrantFiled: August 2, 1993Date of Patent: February 21, 1995Assignee: Albemarle CorportionInventors: K. Pushpananda A. Senaratne, Patrick S. Bynum, Mahmood Sabahi
-
Patent number: 5322633Abstract: Branched chain carboxylic esters are prepared by reacting an unsaturated PAO such as 1-decene dimer with CO and an aliphatic alcohol solvent in the presence of an acid and a noble metal catalyst complex such as RuCl.sub.3 /Ph.sub.3 P or PdCl.sub.3 /Ph.sub.3 P.Type: GrantFiled: November 16, 1992Date of Patent: June 21, 1994Assignee: Albemarle CorporationInventors: K. Pushpananda A. Senaratne, Kenneth C. Lilje
-
Patent number: 5241085Abstract: Cyclic ethers are prepared by reacting an unsaturated olefin oligomer derived from an alpha-olefin monomer containing from about 6 to 20 carbon atoms with an aldehyde in the presence of an acid catalyst.Type: GrantFiled: November 23, 1992Date of Patent: August 31, 1993Assignee: Ethyl CorporationInventors: K. Pushpananda A. Senaratne, Patrick S. Bynum, Kenneth C. Lilje, Edward F. Zaweski
-
Patent number: 5225588Abstract: Hydroxybenzoates such as methylsalicylate are alkylated by reacting a hydroxybenzoate with a polyalphaolefin in the presence of a catalytic amount of SnCl.sub.4.Type: GrantFiled: February 3, 1992Date of Patent: July 6, 1993Assignee: Ethyl CorporationInventors: K. Pushpananda A. Senaratne, Patrick S. Bynum
-
Patent number: 5196552Abstract: Cyclic ethers are prepared by reacting an unsaturated olefin oligomer derived from an alpha-olefin monomer containing from about 6 to 20 carbon atoms with an aldehyde in the presence of an acid catalyst.Type: GrantFiled: October 2, 1991Date of Patent: March 23, 1993Assignee: Ethyl CorporationInventors: K. Pushpananda A. Senaratne, Patrick S. Bynum, Kenneth C. Lilje, Edward F. Zaweski
-
Patent number: 4914233Abstract: A process is provided in which a mixture of alpha- and beta-anomers is converted selectively to the desired beta-thymidine. The process involves the following steps: (a) converting a mixture of alpha- and beta-anomers of tetra-O-acylribofuranose to tri-O-acyl-.beta.-ribothymidine; (b) converting tri-O-acyl-.beta.-ribothymidine to .beta.-ribothymidine; (c) converting .beta.-ribothymidine to 2,2'-anhydro-.beta.-thymidine; (d) converting 2,2'-anhydro-.beta.-thymidine to 2'-halo-2'-deoxy-5-methyluridine; and (e) converting 2'-halo-2'-deoxy-5-methyluridine to beta-thymidine. The mixture of alpha- and beta-anomers of tetra-O-acylribofuranose may be produced by any suitable procedure such as by converting lower alkyl ribofuranoside to the tetra-O-acylribofuranose mixture. The lower alkyl ribofuranosides may in turn be produced by various methods. However, a desirable way of effecting this conversion involves use of D-ribose as the starting material which is converted to the lower alkyl ribofuranoside.Type: GrantFiled: March 1, 1988Date of Patent: April 3, 1990Assignee: Ethyl CorporationInventors: John N. Freskos, K. Pushpananda A. Senaratne
-
Patent number: 4814497Abstract: Particulate aluminum is intimately mixed with an aromatic material that contains at least one ar-halo substituent having an atomic number above 20 and at least one side-chain halo substituent having an atomic number below 20 in the presence of an aqueous alkali or alkaline earth metal hydroxide so as to effect selective removal of the ar-halo substituent.Type: GrantFiled: May 12, 1986Date of Patent: March 21, 1989Assignee: Ethyl CorporationInventor: K. Pushpananda A. Senaratne
-
Patent number: 4629808Abstract: A 6-alkoxy-5-trifluoromethyl-1-cyanonaphthalene is hydrolyzed to the corresponding acid in high yield by reacting it with an aqueous alcoholic base under moderate pressure at a temperature of about 115.degree.-130.degree. C. A preferred nitrile is 6-methoxy-5-trifluoromethyl-1-cyanonaphthalene, preferred bases are sodium and potassium hydroxides, utilizable alcohols are alkanols containing 1-3 carbons, and preferred pressures are in the range of about 90-110 psi.Type: GrantFiled: June 20, 1985Date of Patent: December 16, 1986Assignee: Ethyl CorporationInventor: K. Pushpananda A. Senaratne