Patents by Inventor Hassan Y. Elnagar
Hassan Y. Elnagar 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: 20030194514Abstract: Propargyl bromide is effectively stabilized against shock or thermal decomposition by use therewith of an environmentally acceptable inert liquid solvent that forms an azeotrope with propargyl bromide.Type: ApplicationFiled: April 8, 2002Publication date: October 16, 2003Inventors: Ralph W. Magin, Robert C. Herndon, Mahmood Sabahi, Robert H. Allen, Noel H. Brantley, Hassan Y. Elnagar, Ronny W. Lin
-
Publication number: 20030105350Abstract: A process for thermal benzylic bromination of a wide variety of benzylic compounds is described. Bromine is used as the bromination agent. Moderate temperatures are employed and the process can be used to produce in relatively pure form either mono- or dibrominated benzylic bromination products.Type: ApplicationFiled: December 5, 2001Publication date: June 5, 2003Inventors: Max K. Mortensen, Hassan Y. Elnagar, Ranjit K. Roy, Robert C. Herndon,, Robert H. Allen, David A. Caillet
-
Patent number: 6508954Abstract: Among the enhanced properties of the 1,3-dibromo-5,5-dimethylhydantoins described are their larger average particle sizes, their compactibility even though devoid of a binder, their excellent free-flowing and low-dust properties, and their more appealing aesthetic qualities, as compared to previously known 1,3-dibromo-5,5-dimethylhydantoins. These novel 1,3-dibromo-5,5-dimethylhydantoins can be produced, for example, by concurrently feeding (i) an aqueous solution or slurry formed from an inorganic base and 5,5-dimethylhydantoin, and (ii) a brominating agent, in proportions such that each nitrogen atom is substituted by a bromine atom, thereby forming product which precipitates in an aqueous reaction mixture. The pH of the reaction mixture is maintained in the range of about 5.5 to about 8.5.Type: GrantFiled: January 18, 2000Date of Patent: January 21, 2003Assignee: Albemarle CorporationInventors: Hassan Y. Elnagar, Jonathan N. Howarth, Bruce C. Peters, Edgar E. Spielman, Jr., Dustin H. Thomas
-
Patent number: 6489524Abstract: Aromatic substrates are Ar-brominated in high yield and selectivity by reacting the substrate with a brominating agent in the presence of at least about 0.19 gram per mmol of substrate of a zeolite catalyst which has an absorbed water content of no greater than about 7.5 weight percent.Type: GrantFiled: October 27, 1997Date of Patent: December 3, 2002Assignee: Albemarle CorporationInventors: Mahmood Sabahi, Hassan Y. Elnagar, Robert L. Davis
-
Patent number: 6300527Abstract: This invention relates, inter alia, to a process for the production of tetrabromobisphenol-A by the bromination of bisphenol-A and/or underbrominated bisphenol-A, which process features: a water and water-miscible organic solvent reaction medium; a relatively high reaction temperature; and the presence, in the reaction medium, of both (i) excess unreacted Br2 during the feed of bisphenol-A to the reactor, and (ii) sufficient HBr to protect the tetrabromobisphenol-A produced against undesirable color formation. Tetrabromobisphenol-A precipitates from the reaction mass and is easily recovered. Product of high purity (97% or more) and very low color (APHA of 50 or less) can be produced, even when using large excesses of bromine in the reaction.Type: GrantFiled: July 12, 2000Date of Patent: October 9, 2001Assignee: Albemarle CorporationInventors: Thanikavelu Manimaran, Hassan Y. Elnagar, Richard A. Holub, Alvin E. Harkins, Jr., Bonnie G. McKinnie
-
Patent number: 6218584Abstract: This invention relates, inter alia, to a process for the production of tetrabromobisphenol-A by the bromination of bisphenol-A and/or underbrominated bisphenol-A, which process features: a water and water-miscible organic solvent reaction medium; a relatively high reaction temperature; and the presence, in the reaction medium, of both (i) excess unreacted Br2 during the feed of bis-phenol-A to the reactor, and (ii) sufficient HBr to protect the tetrabromobisphenol-A produced against undesirable color formation. Tetrabromobisphenol-A precipitates from the reaction mass and is easily recovered. Product of high purity (97% or more) and very low color (APHA of 50 or less) can be produced, even when using large excesses of bromine in the reaction.Type: GrantFiled: June 10, 1999Date of Patent: April 17, 2001Assignee: Albemarle CorporationInventors: Thanikavelu Manimaran, Hassan Y. Elnagar, Richard A. Holub, Alvin E. Harkins, Jr., Bonnie G. McKinnie
-
Patent number: 6162953Abstract: This invention relates to a process for the production of tetrabromobisphenol-A by the bromination of bisphenol-A, which process features the addition of bisphenol-A to a reaction mass containing unreacted Br.sub.2 and 30 to 85 wt % water and an alcohol solvent, the reaction mass being at a relatively high temperature.Type: GrantFiled: September 28, 1999Date of Patent: December 19, 2000Assignee: Albemarle CorporationInventors: Bonnie G. McKinnie, Richard A. Holub, Hassan Y. Elnagar
-
Patent number: 6121490Abstract: A process for producing tertiary amine oxide having two methyl or ethyl groups and one long chain primary aliphatic group in a stable, solid form is described. Aqueous 65-90% hydrogen peroxide and tertiary amine having two methyl or ethyl groups and one primary aliphatic hydrocarbyl group of 8-24 carbon atoms are mixed in proportions of ca. 1.1-1.3 moles of hydrogen peroxide per mole of tertiary amine in the presence of carbon dioxide and in the absence of organic solvent. When the conversion of the tertiary amine to tertiary amine oxide in the reaction mass has reached ca. 60-90%, the reaction mass is transferred to a separate vessel and the reaction mass is then allowed to solidify at a temperature of ca. 20-60.degree. C. The process makes possible the production of highly pure solid product without formation of any appreciable amounts of undesirable by-products.Type: GrantFiled: April 14, 1999Date of Patent: September 19, 2000Assignee: Albemarle CorporationInventor: Hassan Y. Elnagar
-
Patent number: 6103926Abstract: Direct preparation of benzylically halogenated alkylbenzoic acid ester from an alkylbenzoic acid ester in which the alkyl group is a primary or secondary alkyl group is carried out. The ester group of the starting ester (i) is devoid of non-aromatic unsaturation and (ii) if an aromatic group, is devoid of ring substitution that would undergo benzylic halogenation. The process comprises slowly feeding halogen continuously and/or intermittently to an agitated solution of the alkylbenzoic acid ester in a liquid halogen-containing solvent maintained at a thermal halogenation temperature such that when the alkyl group of the alkylbenzoic acid ester is a primary alkyl group and monohalogenation is desired, the total amount of halogen fed does not exceed about 0.8 mole of halogen per mole of alkylbenzoic acid ester. If the alkylbenzoic acid ester is a toluic acid ester and dihalogenation is desired, the amount of halogen fed is over 1 mole but no more than about 1.8 moles per mole of the toluic acid ester.Type: GrantFiled: March 12, 1999Date of Patent: August 15, 2000Assignee: Albemarle CorporationInventor: Hassan Y. Elnagar
-
Patent number: 6084136Abstract: This invention relates to a process for the production of tetrabromobisphenol-A by the bromination of bisphenol-A, which process features: (a) feeding to a reaction mass (i) bisphenol-A and (ii) a stream of gaseous bromine, the gaseous stream having a Reynold's No. .gtoreq.40,000; (b) the reaction mass containing from about 50 to about 20,000 ppm unreacted bromine and less than 20 wt % HBr; and (c) the reaction mass having precipitated therefrom tetrabromobisphenol-A, all of (a)(ii), (b) and (c) occurring during the bisphenol-A feed.Type: GrantFiled: June 11, 1998Date of Patent: July 4, 2000Assignee: Albmarle CorporationInventors: Richard A. Holub, Steven R. Alferi, Bonnie G. McKinnie, Hassan Y. Elnagar
-
Patent number: 6084137Abstract: This invention relates to a process for the production of tetrabromobisphenol-A by the bromination of bisphenol-A, which process features the addition of bisphenol-A to a reaction mass containing unreacted Br.sub.2 and 30 to 85 wt. % water and an alcohol solvent, the reaction mass being at a relatively high temperature.Type: GrantFiled: October 21, 1997Date of Patent: July 4, 2000Assignee: Albemarle CorporationInventors: Bonnie G. McKinnie, Richard A. Holub, Hassan Y. Elnagar
-
Patent number: 5900512Abstract: An oxidation process for organic compounds employs stabilized bromine chloride solutions as the oxidizing agent. Organic compounds which contain an oxidizable moiety, such as thioanisole and triphenylphosphine, are rapidly converted to sulfoxides and phosphine oxides, respectively, without over-oxidation.Type: GrantFiled: September 11, 1997Date of Patent: May 4, 1999Assignee: Albemarle CorporationInventors: Hassan Y. Elnagar, Robert L. Davis
-
Patent number: 5861522Abstract: Bridged metallocene compounds are produced by a process of promising commercial utility for plant-sized operations. One of the key steps of the process involves converting a deprotonated silicon-, germanium- or tin-containing ligand into the metallocene. Preferably, and in accordance with an embodiment of the invention, this is accomplished to great advantage by adding a diamine adduct of a Group IV, V, or VI metal tetrahalide to a solution or slurry formed from a deprotonated silicon-, germanium- or tin-containing ligand and an organic liquid medium so as to form a metallocene. The overall process of the invention involves the direct conversion of benzoindanones to benzoindanols which, without isolation, are converted to benzoindenes. Thereupon the benzoindenes are bridged by deprotonating the benzoindenes with a strong base such as butyllithium and reacting the resultant deprotonated product with a suitable silicon-, germanium- or tin-containing bridging reactant such as dichlorodimethylsilane.Type: GrantFiled: May 8, 1997Date of Patent: January 19, 1999Assignee: Albemarle CorporationInventors: Meng-Sheng Ao, Hassan Y. Elnagar, Arcelio J. Malcolm, Jamie R. Strickler, Ronny W. Lin, John F. Balhoff
-
Patent number: 5817888Abstract: A bromination process for organic compounds employs stabilized bromine chloride solutions as the brominating agent. Activated aromatic compounds such as anisole can be selectively monobrominated in the para-position in high purity and yield.Type: GrantFiled: June 9, 1997Date of Patent: October 6, 1998Assignee: Albemarle CorporationInventors: Hassan Y. Elnagar, Robert L. Davis, Mahmood Sabahi
-
Patent number: 5710299Abstract: Bridged metallocene compounds are produced by a process of promising commercial utility for plant-sized operations. The overall process involves the direct conversion of benzoindanones to benzoindanols which, without isolation, are converted to benzoindenes. Thereupon the benzoindenes are bridged by deprotonating the benzoindenes with a strong base such as butyllithium and reacting the resultant deprotonated product with a suitable silicon-, germanium- or tin-containing bridging reactant such as dichlorodimethylsilane. The resultant bridged product is deprotonated with a strong base such as butyllithium and reacted with a suitable Group IV, V, or VI metal-containing reactant such as ZrCl.sub.4 to provide a silicon-, germanium- or tin-bridged Group IV, V, or VI metal complex, such as a dihydrocarbylsilyl-bridged zirconocene complex.Type: GrantFiled: June 27, 1996Date of Patent: January 20, 1998Assignee: Albemarle CorporationInventors: Meng-Sheng Ao, Hassan Y. Elnagar, Arcelio J. Malcolm, Jamie R. Strickler
-
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: 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: 5565600Abstract: Novel alkyl-aromatic diphosphites having antioxidant and flame-retarding abilities and corresponding to the formula: ##STR1## can be prepared by reacting a 2,2'-bridged bisphenol corresponding to the formula: ##STR2## with pentaerythritol dichlorophosphite at 20-150.degree. C. in the presence of a basic catalyst; R and R' in the formulas representing hydrocarbyl groups, R" being a divalent bridging group, and n being 0 or 1. These diphosphites have good hydrolytic stability per se and can be made even more resistant to hydrolysis by stabilizing them with at least 0.5% by weight of an acid scavenger, preferably before they are recovered from their synthesis reaction mixtures.Type: GrantFiled: June 26, 1995Date of Patent: October 15, 1996Assignee: Albemarle CorporationInventor: Hassan Y. Elnagar
-
Patent number: 5103035Abstract: Bis(alkylphenyl)pentaerythritol diphosphite is produced by forming a reaction mass from phosphorous trichloride, pentaerythritol, a chlorinated hydrocarbon solvent and a heterocyclic tertiary amine catalyst followed by the addition of an alkylphenol to the reaction mass. The process further features the use of mild conditions.Type: GrantFiled: April 5, 1990Date of Patent: April 7, 1992Assignee: Ethyl CorporationInventors: Hassan Y. Elnagar, Kestutis A. Keblys