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7834221 Process for the preparation of tetrabromobisphenol A  
A process for preparing tetrabromobisphenol A, which comprises: i) reacting bisphenol A and bromine in dichloromethane in the presence of aqueous hydrogen peroxide at a temperature in the range of...
7399890 Method for the hydrodehalogenation of halogenated meta-cresols  
The present process serves for the hydrodehalogenation of halogenated meta-cresols of the formula (I) in which the R1 to R4 radicals are each as defined in the description, and is characterized in...
7053251 Bromination of hydroxyaromatic compounds  
A method for brominating hydroxyaromatic compounds to form products, such as p-bromophenol, is disclosed. The method uses elemental bromine as the brominating agent and comprises contacting a...
7045666 Bromination of hydroxyaromatic compounds and further conversion to dihydroxyaromatic compounds  
Brominated hydroxyaromatic compounds such as p-bromophenol are prepared by contacting a hydroxyaromatic compound with oxygen and a bromine source such as hydrogen bromide or an alkali metal or...
7022886 Selective catalytic oxybromination of hydroxyaromatic compounds  
A method for selectively brominating hydroxyaromatic compounds is disclosed. Hydroxyaromatic compounds are contacted with oxygen and a bromine source, in an acidic medium, in the presence of a...
6982356 Method for preparation of para-brominated hydroxyaromatic compounds  
A method for preparing hydroxyaromatic compounds brominated in the para-position, such as p-bromophenol, is disclosed. The method yields overall high process selectivity through isomeric...
6815565 Method for preparing hydroquinones and dihydroxybiphenyl compounds from mixtures of bromophenols and benzoquinones  
A method is described for the simultaneous preparation of p-bromophenols and p-benzoquinones, intermediates useful in the preparation of hydroquinones and 4,4′-dihydroxybiphenyls, respectively....
6740253 Preparation of non-hazardous brominating reagents  
The present invention relates to a non-hazardous brominating reagent from an aqueous alkaline bromine byproduct solution obtained from bromine recovery plant and containing 25 to 35% bromine...
6693221 Method of preparing mixtures of bromophenols and benzoquinones  
A method is described for the simultaneous preparation of 4-bromophenols and p-benzoquinones, intermediates useful in the preparation of hydroquinones and 4,4′-dihydroxybiphenyls respectively....
6313355 Process for the preparation of tetrabromobisphenol-A  
Tetrabromobisphenol-A is produced in a bromination process where no bromine or only a very small proportion of bromine is fed to the reactor. In the process aqueous hydrobromic acid, is the sole...
6265621 Process for producing halogenated phenol compounds  
The present invention provides a process for producing a halogenated phenol compound represented by the general formula [II]: ##STR1##wherein Q is a monovalent organic residue, A is, the same or...
6162953 Process for the preparation of tetrabromobisphenol-A  
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...
6084136 Process for the preparation of tetrabromobisphenol-A  
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...
5907063 Aromatic bromination process  
Activated aromatic compounds are more economically ring brominated by reacting the compounds with a sulfoxide/HBr brominating agent while removing water from the reaction mixture. The water...
5847236 Process for the preparation of 2-chloro-4-methylphenol  
2-Chloro-4-methylphenol is prepared by reacting 4-methylphenol with a chlorinating agent in the presence of a catalyst system of one or more Lewis acids in a total amount of 0.1-10% by weight and...
5817890 Process for preparation of halogenated or pseudohalogenated cyclic organic compounds  
The present invention relates to new fluorinated hexane compounds corresponding to the following general formula (II): ##STR1## in which X'2, X'3, and X'4 are the same or different, and denote a...
5696302 Highly concentrated aqueous tribromophenolate solution and a method for preparing the same  
A highly concentrated aqueous tribromophenolate solution containing a non-hydrophillic solvent and a reducing agent is prepared by dissolving an alkali and a reducing agent in water, adding a...
5484932 Halogenation processes in advantageous solvents, and novel bistrifluoromethyl-polyfluoroalkoxybenzenes  
Compounds such as ##STR1## wherein R is F, CF3, CF2 H, CHF CF3 or CF2 CF3, as well as related compounds containing chlorine, are used as solvents in halogenation processes.
5475153 Process to produce tetrabromobisphenol with the reduced formation of alkyl bromide by-products  
A process for the preparation of 4,4'-isopropylidene bis(2,6-dibromophenol), also known as tetrabrombisphenol A, that dramatically reduces the formation of alkyl bromide by-products. Bisphenol A...
5446212 Reduced methyl bromide process for making tetrabromobisphenol-A  
A reduced methyl bromide process for making tetrabromobisphenol A in methanol, including: dissolving bisphenol-A in a methanol solvent to form a bisphenol-A methanol solution, adding bromine to...
5426243 Process for preparing 1,6-dibromo-2-naphthylene compounds  
An improved process for the preparation of 1,6-dibromo-2 -naphthol is disclosed. The improvement is accomplished by carrying out the reaction in an organic solvent at a temperature of from about...
5387725 Chlorination process, alkylation of products of said process and some products thereof  
Compounds having acidic protons and a molecular structure which can delocalize the electron density of the conjugate base (target compounds) are chlorinated by contacting such compounds with a...
5283375 Process for high purity tetrabromobisphenol-A  
This invention relates to a process for preparing a flame retardant product predominant in tetrabromobisphenol-A. The process comprises: (a) dissolving bisphenol-A in a methanol solvent containing...
5149858 Selective ortho-chlorination of phenols  
Phenolic compounds, notably admixtures of 2,4-dichlorophenol and 2,6-dichlorophenol, are selectively chlorinated at the ortho positions thereof, with gaseous chlorine and in a molten medium, in...
5118874 Partially fluorinated biphenyls, processes for their preparation and their use  
Compounds of the formula ##STR1## in which, independently of one another, each R is OH or lower alkyl having 1-4 carbon atoms and each R' is hydrogen or lower alkyl having 1-4 carbon atoms, are...
5059722 Tetrabromobisphenol-A process  
Tetrabromobisphenol-A is made in high purity by adding a methanol-bromine solution to a methanol-bisphenol-A solution with vigorous agitation. Use of the bromine-methanol solution reduces the...
5053557 Process for preparing 2-chloro-4-fluorophenol  
A process is disclosed for preparing 2-chloro-4-fluorophenol which comprises chlorinating 4-fluorophenol with a chlorinating agent in the presence of water. The process according to the present...
5026926 Chlorination of ortho-chlorophenol  
The polychlorophenols, e.g., 2,6-dichlorophenol (a known agrochemical intermediate), are effectively prepared by chlorinating ortho-chlorophenol with gaseous chlorine, optionally in the presence...
5017728 Tetrabromobisphenol-A process  
Tetrabromobisphenol-A is made in high purity and increased yield by adding a methanol-bromine solution to a methanol bisphenol-A solution with vigorous agitation. The amount of methanol in the...
4997946 Process for the iodination of hydroxyaromatic and aminoaromatic compounds  
A method of iodinating hydroxyaromatic and aminoaromatic compounds is disclosed, comprising reacting the hydroxyaromatic or aminoaromatic compound with an aqueous solution of a metal iodide and a...
4954662 Selective chlorination of ortho-substituted phenols  
Ortho-substituted phenolic compounds, e.g., 2,6-dichlorophenol, are selectively chlorinated, e.g., into 2,4,6-trichlorophenol, with gaseous chlorine in either the molten state or in a solvent...
4940807 Selective bromination of aromatic compounds using potassium tribromide  
Electron-rich aromatic compounds are selectively brominated in good yield in the presence of water using potassium tribromide as the brominating agent. In this way monobromination is favored and...
4885408 Chlorination of ortho-substituted phenols  
The ortho-substituted phenols, e.g., 2,6-dichlorophenol, are reacted with gaseous chlorine, in the presence of a catalytically effective amount of a strong or Lewis acid, to produce, e.g., a more...
4876396 Selective chlorination of phenols  
Phenolic compounds and mixtures thereof, e.g., admixture of 2,4-dichlorophenol and 2,6-dichlorophenol, are selectively chlorinated at a position ortho to a hydroxyl function thereof, by reacting...
4855513 Chlorination of phenolic compounds  
The chlorophenols, e.g., 2,4,6-trichlorophenol, are efficiently prepared by chlorinating an ortho-/para-substituted phenolic compound with gaseous chlorine, whether in molten state or in a solvent...
4855514 Oxidative iodination of phenol  
A process for producing iodophenols which comprises contacting phenol, a source of iodine and molecular oxygen in an aqueous medium to produce an iodophenol.
4827047 Chlorination of nitrophenols  
The chloronitrophenols, e.g., 2,6-dichloro-4-nitrophenol (a known agrochemical/pharmaceutical intermediate), are efficiently prepared by chlorinating ortho- or para-nitrophenol with gaseous...
4754080 Chemical composition and use thereof  
This invention relates to novel compositions comprising a N-halodialkylamine as defined in the specification and an inorganic oxide. The compositions are useful as halogenating agents for phenolic...
4740636 Di-ortho-substituted di-meta-halogenated para-halomethylphenols  
Included is a process to prepare a 4-HALOmethyl-3,5-dihalo-2,6-disubstitutedphenol from a 4-methyl(substituted)phenol and a HALOgenating agent, in an aprotic organic diluent. The process is highly...
4723043 Nitration of phenolic compounds  
Substituted phenols are nitrated by contacting same with a 10 to 70% by weight concentrated aqueous solution of nitric acid. The subject nitration process is well adopted for the preparation,...
4701568 Process for preparing tetrabromobisphenol-A  
Tetrabromobisphenol-A is made in high purity by contacting a solution of bisphenol-A dissolved in a C1 -C4 alkanol with gaseous bromine.
4683346 Selective preparation of monohalohydroquinones  
Hydroquinone is selectively nascently chlorinated to monochlorohydroquinone, by reacting same with an aqueous solution of hydrochloric acid and hydrogen peroxide, in the presence of an organic...
4668831 Tert-Butyl-halophenols  
3-tert-Butyl-4-halophenols which are useful as intermediates for preparing compounds having medical or agricultural activities.
4620042 Preparation of 2-chloro-4-fluorophenol from 4-fluorophenol  
2-Chloro-4-fluorophenol is obtained with good yield by direct chlorination of 4-fluorophenol with chlorine gas at 0°-185° C. in the absence of catalyst. In a combination of these reactants, the...
4612401 Process for the preparation of 4-hydroxy-2,4,6-trimethyl-2,5-cyclohexadienone  
4-Hydroxy-2,4,6-trimethyl-2,5-cyclohexadienone is made by chlorinating 2,4,6-trimethylphenol with chlorine in an organic solvent in the absence of base while the hydrogen chloride formed is...
4575571 Process for the simultaneous halogenation and fluorination of aromatic derivatives  
A process for the stimulaneous halogenation and fluorination of aromatic derivatives substituted by at least one group containing a halogenoalkyl unit. The aromatic derivative is reacted with the...
4564714 Process for the preparation of 2,4,5-trichlorophenol under acidic conditions  
A novel process for the preparation of 2,4,5-trichlorophenol which comprises selectively chlorinating 2,5-dichlorophenol under acidic conditions.
4547597 Preparation of halogenated phenols  
Halogenated phenolic compounds are prepared by forming a low melting point complex of the phenolic compound and contacting the low melting point complex with a halogenating agent under...
4518808 Preparation of 2,5-dichlorohydroquinone  
Disclosed is a process for the preparation of certain dichloro-hydroxy and alkoxy aromatic compounds by reacting the corresponding unchlorinated compound with sulfuryl chloride in the presence of...
4517388 Process for the selective preparation of parabromophenol and its derivatives  
This invention is a process for the preparation of para-bromo-phenole derivatives of the formula I ##STR1## wherein R1, R2 R3, R4 and R5 each independently represents hydrogen or lower alkyl...

Matches 1 - 50 out of 101 1 2 3 >