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| Number | Title | Issue Date |
| 8071817 | Preparation of purified hydroquinone and forming of same Purified hydroquinone is prepared and formed from raw compounds essentially containing hydroquinone associated with very small quantities of impurities including resorcinol and pyrogallol, and includes a distillation purification step in which the resorcinol and pyr... | 12/06/2011 |
| 7235299 | Beads of a phenolic compound and a method of obtaining same The present invention relates to a novel presentation of a phenolic compound in the solid form. More particularly, the invention provides beads of hydroquinone. The invention also pertains to the preparation of said beads. The process of the invention is characteriz... | 06/26/2007 |
| 7115785 | Method for making salts hydroxy-substituted hydrocarbons Disclosed is a method for preparing an alkali metal salt of a hydroxy-substituted hydrocarbon which comprises the steps of (i) contacting in solvent media at least one hydroxy-substituted hydrocarbon with a base comprising an alkali metal cation; and (ii) devolatili... | 10/03/2006 |
| 6960698 | Method for treating tar A method for treating tar separated from a liquid containing an aromatic hydroxybenzene obtained by acidolysis of a liquid containing an aromatic hydroperoxide, which comprises dissolving the tar with an alkaline aqueous solution. ... | 11/01/2005 |
| 6930211 | Production methods of citalopram and intermediates therefor The present invention provides a production method of a compound of the formula wherein X is chlorine atom, bromine atom or iodine atom, as well as a production method of citalopram and intermediates therefor. ... | 08/16/2005 |
| 6844472 | Method and installation for separating and purifying diphenols in the phenol and phenol derivatives industry A method and installation for separating and purifying a crude mixture containing hydroquinone, resorcinol and possibly tars and/or catechol, comprising the following steps: —a possible distillation stage (I) in order to obtain a catechol head, —the foot (I) or ... | 01/18/2005 |
| 6554967 | Method of refining dihydroxyaryl compound A refined dihydroxyaryl compound, for example, catechol, having a high degree of purity and a very low metal content is produced by evaporating a starting dihydroxyaryl compound in a distillation column, condensing the vapor fraction in a condenser connec... | 04/29/2003 |
| 6479711 | Process for producing aromatic hydroxy compound A process for producing an aromatic hydroxy compound having hydroxyl group at the para-position with respect to a hydroxy or an alkoxy substituent group present in the aromatic ring at a high yield and at a high selectivity, using a novel and useful hydro... | 11/12/2002 |
| 6437179 | Process for the preparation of fluorogenic phenolic compounds A method is disclosed for preparing a fluorogenic phenolic compound with improved optical qualities for use in formulating a substrate solution for assay of peroxidase or peroxide activity. The method involves forming a solution under anoxic conditions wh... | 08/20/2002 |
| 6271424 | Process for the purification of monotertiarybutyl hydroquinone The present invention relates to a method of making purified monotertiarybutyl hydroquinone containing less than 0.2% (wt.) of 2,5 ditertiarybutyl hydroquinone. This method includes heating a composition of monotertiarybutyl hydroquinone and 2,5 ditertiar... | 08/07/2001 |
| 6184367 | Process for the production of 4-aryl-2 butanols from Taxus wallichiana The present invention provides a process for the production of two molecules of 4-aryl-2 butanols having the general formula 1 given below: ##STR1## Wherein R.dbd.H or glucose from the leaves of Taxus wallichiana, which comprises: (a) defatting air dried,... | 02/06/2001 |
| 5840999 | Asymmetric benzoxanthene dyes A class of asymmetric monobenzoxanthene compounds useful as fluorescent dyes are disclosed having the structure ##STR1## wherein Y1, and Y2 are individually hydroxyl, amino, imminium, or oxygen, R1 -R8 are ... | 11/24/1998 |
| 5679223 | Method for separating and purifying catechol mixtures An extractive distillation process using a high boiling polyol such as glycerol is employed for separating high purity catechol, 3-methylcatechol and 4-methylcatechol from a high boiling, pitch-like dihydric phenol fraction. Fractional distillation first ... | 10/21/1997 |
| 5512700 | Process for purifying a bisphenol A process for the purification of a crude bisphenol comprises the following steps: (1) preparing a mixture comprising from about 35 to about 70% of a crude bisphenol and from about 65 to about 30% of water, by the total weight of bisphenol and water, with... | 04/30/1996 |
| 5336814 | Method for recovering bis hydroxy aromatic organic values and bis aryl carbonate values from scrap aromatic polycarbonate A method is provided for depolymerizing scrap aromatic polycarbonate to salvage component monomers by initially effecting aromatic polycarbonate depolymerization by basic phenolysis to produce a mixture having dihydric phenol, and diarylcarbonate. Recover... | 08/09/1994 |
| 5198591 | Method to manufacture bisphenol A The invention relates to a process for obtaining a high purity bisphenol from a post-reaction mixture resulting from the step of synthesis of phenol and acetone in the presence of a strong acid cation exhanger catalyst, by the way of crystallation and sep... | 03/30/1993 |
| 5177269 | Removal of guaiacol from cresylic acid feedstreams by heating with a strong acid A process is described for the removal of guaiacol from naturally occurring cresylic acid feed by heating the feed with a strong acid, particularly hydrochloric acid or sulfuric acid, to produce a purified cresylic acid product essentially free of guaiaco... | 01/05/1993 |
| 5124490 | Removal of acids from phenol using anionic exchange resins Acid contaminants leached from acidic ion-exchange resins and carried in process streams with phenol are separated from the phenol by passing the process stream in contact with an anionic exchange resin, whereby the acid contaminants react with and bond t... | 06/23/1992 |
| 5087771 | Process for the purification of monotertiarybutyl hydroquinone A process for producing food-grade tertiary-butyl hydroquinone from impure montertiary butyl hydroquinone is provided. Impure monotertiary butyl hydroquinone crystals are agitated at an elevated temperature while in contact with a non-polar solvent under ... | 02/11/1992 |
| 4851590 | Method of purifying 2,4-xylenol 2,4-Xylenol can be obtained in high yield and high purity from a crude 2,4-xylenol isomer mixture containing 2,5-xylenol by selectively reacting the 2,5-xylenol with an aldehyde in the presence of an aromatic sulfonic acid, thereby converting the 2,5-xyle... | 07/25/1989 |
| 4827049 | Process for the separation of dihydroxybenzene isomers This invention comprises a process for separating isomers of dihydroxybenzene (DHB) from a feed mixture comprising at least two of said isomers, which process comprises contacting the mixture at adsorption conditions with an adsorbent comprising a Y type ... | 05/02/1989 |
| 4795829 | Process for separating higher molecular weight constituents from phenol polymers A process for separating higher molecular weight constituents from phenol polymers, wherein the phenol polymer is dissolved in an organic solvent medium, the solution obtained is mixed at room temperature with ammonia or an amine such that there is a stoi... | 01/03/1989 |
| 4614814 | Monoalkylation of dihydroxy aromatic compounds There is disclosed a process for the reduction of the diether impurities formed when a dihydroxy aromatic compound is reacted with an alkylating agent in an alcoholic solvent in the presence of two to three equivalents of base. The diether impurities are ... | 09/30/1986 |
| 4546207 | Process for preparing anhydrous salts of dihydroxyaromatic compounds Anhydrous di-(alkali metal) (especially disodium) salts of dihydroxyaromatic compounds such as bisphenol A are prepared by first contacting the solid dihydroxyaromatic compound with an aqueous alkali metal hydroxide solution so as to convert it into the s... | 10/08/1985 |
| 4538007 | Process for the simultaneous recovery of 4-hydroxy-diphenyl and 4,4'-dihydroxydiphenyl 4-Hydroxydiphenyl (mono-OD) and 4,4'-dihydroxydiphenyl (DOD) are obtained simultaneously from a mixture which contains these two substances, if such a mixture is treated with an aqueous alkali, and the resulting solution and the solid phase formed are sep... | 08/27/1985 |
| 4503267 | Extraction of phenolics from hydrocarbons Polyethylene glycols have been found to be selective solvents for the extraction of phenolic compounds from admixture with hydrocarbons.... | 03/05/1985 |
| 4463197 | Method for purifying phloroglucin A method for purifying phloroglucin wherein crude phloroglucin obtained by an acid-decomposition of 1,3,5-triisopropylbenzene trihydroperoxide in the presence of a solvent and removal of the formed acetone and the solvent by evaporation, is extraction-tre... | 07/31/1984 |
| 4460799 | Process for the preparation of ortho-hydroxybenzyl alcohols This invention relates to a process for the selective preparation of ortho-hydroxybenzyl alcohols and, in particular, ortho-hydroxybenzyl alcohol. According to the invention, the reaction of a phenol with an aldehyde in an initially anhydrous medium and i... | 07/17/1984 |
| 4424381 | Process for separating dihydric phenols A process is disclosed for separating closely-boiling dihydric phenol compounds by treating a mixture of dihydric phenols with a metal halide salt. The metal halide salt preferentially forms a complex with one of the dihydric phenols over other related di... | 01/03/1984 |
| 4420376 | Separation of resorcinol from non-extractable impurities An improved process for recovering high purity resorcinol produced by the rearrangement of m-diisopropylbenzene dihydroperoxide in which the rearranged product mixture is neutralized, the neutralized mixture being filtered, the filtrate being admixed with... | 12/13/1983 |
| 4420643 | Extraction of phenols from aqueous solutions A process for the extraction of phenolic compounds from aqueous solutions is disclosed. The process comprises contacting said aqueous solution with an organic solution comprising at least one tertiary phosphine oxide and a high boiling organic solvent.... | 12/13/1983 |
| 4420642 | Selective removal and recovery of catechol mixed with 2-methallyloxyphenol A process is disclosed for selectively removing catechol from a mixture comprising catechol, 2-methallyloxyphenol, various salts, and by-products by treating the mixture with aqueous base, the aqueous phase being preferably saturated with respect to salts... | 12/13/1983 |
| 4414422 | Purification of 4,4-dihydroxybiphenyl 4,4'-Dihydroxybiphenyl is purified to remove sulfur-containing impurities, color bodies and/or phenyl-substituted phenol compounds by heating in the presence of a mixture of water and a water-miscible organic compound selected from acetone and C1-6 | 11/08/1983 |
| 4381973 | Process for the preparation of pyrocatechol and hydroquinone A process for the preparation of pyrocatechol and hydroquinone by reaction of phenol with a peroxidic hydroxylating reagent followed by working-up of the resultant reaction mixture is disclosed. The work-up procedure is carried out in a first rectificatio... | 05/03/1983 |
| 4379939 | Preparation of nitrogen fertilizers from oxalate esters prepared by the oxidative carbonylation of alcohols over noble metal catalysts utilizing regenerable 2,5-cyclohexadiene-1,4-dione oxidants A process for the preparation of nitrogen fertilizers, especially oxamide, either indirectly, or directly from oxalate esters, including the regeneration of the quinone oxidant utilized in the formation of the above esters. Preparation of oxalate esters a... | 04/12/1983 |
| 4362604 | Process for the preparation of pyrocatechol and hydroquinone A process for the isolation of hydroquinone, pyrocatechol, phenol and carboxylic acid from the reaction mixture containing the same such as one obtained by reaction of phenol with percarboxylic acid is disclosed. The reaction mixture is fed to a first rec... | 12/07/1982 |
| 4355190 | Process for recovery of resorcinol from aqueous resorcinol solution containing hydroquinone A process for recovery of resorcinol from an aqueous resorcinol solution containing hydroquinone which comprises oxidizing an aqueous resorcinol solution containing about 10 to about 60% by weight of resorcinol and up to about 1% by weight of hydroquinone... | 10/19/1982 |
| 4354046 | Process for obtaining high purity bisphenol A A method of purifying bisphenols by (1) crystallizing the crude bis from a single liquid phase containing water, bis and an organic solvent, (2) stripping the remaining mother liquor (containing the impurities) of solvent and water, and (3) mixing it with... | 10/12/1982 |
| 4352944 | Treatment of cashew nut shell liquid The components of cashew nut shell liquid have such similar physical characteristics that their separation into relatively pure components has been difficult and has prevented use of the oil in many technological areas. The reaction of certain components ... | 10/05/1982 |
| 4351966 | Phenol recovery from bisphenol-A waste streams Bisphenol-A waste stream derived from the reaction of phenol and acetone in the presence of an acidic condensing agent can be treated with a molecular sieve to obtain good yields of phenol present in the effluent stream either in isolated form or as part ... | 09/28/1982 |
