Abstract: In a cyclic anthraquinone process for producing hydrogen peroxide, which comprises a distillation unit with vapor compression for concentrating hydrogen peroxide, aqueous condensate from the distillation unit is passed over a bed of a cation exchange resin in its protonated from to provide a purified condensate, and the purified condensate is used as extractant for extracting hydrogen peroxide in the anthraquinone process, as column reflux for the distillation unit or as a diluent for diluting an aqueous hydrogen peroxide solution.

Abstract: A method for preparing 1,2-propanediol involves reacting propene with hydrogen peroxide in the presence of a catalyst mixture, containing a phase transfer catalyst and a heteropolytungstate, in a liquid reaction mixture containing an aqueous phase with a maximum apparent pH of 6 and an organic phase. The method then involves separating the reaction mixture into an aqueous phase (Pa) containing 1,2-propanediol and formic acid and an organic phase (Po); recycling at least part of the separated organic phase (Po) to the reaction; contacting at least a part of the separated aqueous phase (Pa) with a palladium catalyst; and recovering 1,2 propanediol from the aqueous phase provided by the contacting. The contacting of at least a part of the separated aqueous phase (Pa) with the palladium catalyst reduces the content of formic acid.

Abstract: The transport container for concentrated hydrogen peroxide comprises: a cuboid carrier frame; a liquid container provided inside the carrier frame (1) and frictionally connected thereto, said container having an internal volume of between 65 and 500 I and consisting of pure aluminium, chromium-nickel steel, a nickel-based alloy, or a steel coated with a polyolefin or clad on the inner face; a pressure equalisation device and a pressure relief valve, both of which are provided on the upper face of the liquid container; and at least one sealable opening of the liquid container for the charging and/or removal of hydrogen peroxide.

Abstract: A method can be used for preparing 1,2-propanediol, dipropylene glycol, and tripropylene glycol. The method involves reacting propene with hydrogen peroxide containing nitrate, in the presence of a catalyst mixture containing a phase transfer catalyst and a heteropolytungstate, in a liquid reaction mixture containing an aqueous phase with a maximum apparent pH of 6 and an organic phase. The method then involves separating the reaction mixture into an aqueous phase containing 1,2-propanediol, dipropylene glycol, tripropylene glycol, and nitrate and an organic phase. The method further involves recycling at least part of the separated organic phase to the reaction; hydrogenating the separated aqueous phase using a heterogeneous hydrogenation catalyst to provide a hydrogenated aqueous phase with a reduced nitrate content; and recovering 1,2-propanediol, dipropylene glycol, and tripropylene glycol from the hydrogenated aqueous phase by a sequential multiple-step distillation.

Abstract: In a cyclic anthraquinone process for producing hydrogen peroxide, which comprises a distillation unit with vapor compression for concentrating hydrogen peroxide, aqueous condensate from the distillation unit is passed over a bed of a cation exchange resin in its protonated from to provide a purified condensate, and the purified condensate is used as extractant for extracting hydrogen peroxide in the anthraquinone process, as column reflux for the distillation unit or as a diluent for diluting an aqueous hydrogen peroxide solution.

Abstract: An aqueous hydrogen peroxide solution containing i) less than 50 wppm alkali metals, alkaline earth metals or combinations thereof in total, irrespective whether the alkali or alkaline earth metals are present in cationic or complex form; ii) less than 50 wppm of amines having a pkB of less than 4.5 or the corresponding protonated compounds in total; and iii) at least 100 wppm anions or compounds that can dissociate to form anions in total, where the wppm are based on the weight of hydrogen peroxide and the concentration of hydrogen peroxide is more than 50% by weight based on the total weight of the hydrogen peroxide solution. A process for preparation of said hydrogen peroxide solution and the use of said solution in a process for epoxidation of olefins is also disclosed.

Abstract: An aqueous hydrogen peroxide solution containing i) less than 50 wppm alkali metals, alkaline earth metals or combinations thereof in total, irrespective whether the alkali or alkaline earth metals are present in cationic or complex form; ii) less than 50 wppm of amines having a pkB of less than 4.5 or the corresponding protonated compounds in total; and iii) at least 100 wppm anions or compounds that can dissociate to form anions in total, where the wppm are based on the weight of hydrogen peroxide and the concentration of hydrogen peroxide is more than 50% by weight based on the total weight of the hydrogen peroxide solution. A process for preparation of said hydrogen peroxide solution and the use of said solution in a process for epoxidation of olefins is also disclosed.

Abstract: An aqueous hydrogen peroxide solution containing i) less than 50 wppm alkali metals, alkaline earth metals or combinations thereof in total, irrespective whether the alkali or alkaline earth metals are present in cationic or complex form; ii) less than 50 wppm of amines having a pkB of less than 4.5 or the corresponding protonated compounds in total; and iii) at least 100 wppm anions or compounds that can dissociate to form anions in total, where the wppm are based on the weight of hydrogen peroxide and the concentration of hydrogen peroxide is more than 50% by weight based on the total weight of the hydrogen peroxide solution. A process for preparation of said hydrogen peroxide solution and the use of said solution in a process for epoxidation of olefins is also disclosed.

Abstract: The invention concerns a process for the preparation of hydrogen peroxide by the anthraquinone cyclic process. The process includes a regeneration stage in which working solution is regenerated by being brought into contact with an aqueous solution containing an alkyl anthrahydroquinone and/or an alkyl tetrahydroanthrahydroquinone in deprotonated form. The working solution regenerated in the regeneration stage is returned to the cyclic process.

Abstract: The invention relates to a process for the production of hydrogen peroxide by the anthraquinone process, comprising a hydrogenation stage, an oxidation stage and an extraction stage. According to the invention, catalytic hydrogenation of anthraquinone derivatives dissolved in a working solution is carried out in the presence of added molecular oxygen. Per mol hydrogen, 0.1 to 10 mmol oxygen is preferably introduced into the hydrogenation stage with the hydrogenating gas, in mixture with an inert gas and/or dissolved and/or dispersed in the working solution. This increases the residence time of the catalyst.

Abstract: The invention concerns a process for the preparation of hydrogen peroxide by the anthraquinone cyclic process. The process includes a regeneration stage in which working solution is regenerated by being brought into contact with an aqueous solution containing an alkyl anthrahydroquinone and/or an alkyl tetrahydroanthrahydroquinone in deprotonated form. The working solution regenerated in the regeneration stage is returned to the cyclic process.

Abstract: The invention relates to a process for the production of hydrogen peroxide by the anthraquinone process, comprising a hydrogenation stage, an oxidation stage and an extraction stage. According to the invention, catalytic hydrogenation of anthraquinone derivatives dissolved in a working solution is carried out in the presence of added molecular oxygen. Per mol hydrogen, 0.1 to 10 mmol oxygen is preferably introduced into the hydrogenation stage with the hydrogenating gas, in mixture with an inert gas and/or dissolved and/or dispersed in the working solution. This increases the residence time of the catalyst.

Abstract: An aqueous hydrogen peroxide solution containing i) less than 50 wppm alkali metals, alkaline earth metals or combinations thereof in total, irrespective whether the alkali or alkaline earth metals are present in cationic or complex form; ii) less than 50 wppm of amines having a pkB of less than 4.5 or the corresponding protonated compounds in total; and iii) at least 100 wppm anions or compounds that can dissociate to form anions in total, where the wppm are based on the weight of hydrogen peroxide and the concentration of hydrogen peroxide is more than 50% by weight based on the total weight of the hydrogen peroxide solution. A process for preparation of said hydrogen peroxide solution and the use of said solution in a process for epoxidation of olefins is also disclosed.

Abstract: A process for the concentration of aqueous hydrogen peroxide by discontinuous crystallization. A cooling surface is arranged in a crystallizing vessel and first wetted with hydrogen peroxide and then cooled at a high cooling rate, whereupon seed crystals form. The cooling rate is at least 1 K/s, preferably from 10 to 30 K/s. When the vessel has been filled with H2O2 starting material, the latter crystallizes, starting from the seed crystals, and forms a crystal layer. When the mother liquor of lower H2O2 concentration has been discharged, there follows a sweating operation with a slow increase in temperature, as a result of which the H2O2 concentration in the crystal layer is increased further.

Abstract: Process for producing hydrogen peroxide The invention relates to a process for producing hydrogen peroxide by the cyclic anthraquinone process. According to the invention, the rate of oxidation of a hydrogenated working solution containing a tetrahydroanthrahydroquinone derivative is increased if the oxidation is carried out in the presence of a secondary amine. Preferably a slightly water-soluble secondary amine having a boiling point of at least 150° C., in a quantity of 0.001 to 2 mol per mol of tetrahydro compounds, is used.

Abstract: In carrying out the hydrogenation stage of the anthraquinone process for the preparation of hydrogen peroxide in a hydrogenation reactor on a fixed bed catalyst of a particulate catalyst, the service life of the catalyst is increased in that the working solution comprising the reaction carrier and a gas phase comprising hydrogen, are passed through the hydrogenation reactor from the bottom upwards. The empty tube speed of the working solution is 0.05 to 100 m/h, preferably 10 to 50 m/h.

Abstract: A method for producing 2-(4-methyl-3-pentenyl)anthraquinone (IHEAQ) that includes a Diels-Alder addition of naphtho-1,4-quinone and myrcene and an oxidation of the resulting adduct. The oxidation step is carried out in the presence of a solvent mixture that contains a polar and a nonpolar solvent. The oxidation takes place with air or an O2-containing gas in the presence of a combination of a strong inorganic base and an organic, especially a nitrogen-containing base. The method leads to a higher space-time yield and higher product purity.

Abstract: A process for the concentration of aqueous hydrogen peroxide by discontinuous crystallization. A cooling surface is arranged in a crystallizing vessel and first wetted with hydrogen peroxide and then cooled at a high cooling rate, whereupon seed crystals form. The cooling rate is at least 1 K/s, preferably from 10 to 30 K/s. When the vessel has been filled with H2O2 starting material, the latter crystallizes, starting from the seed crystals, and forms a crystal layer. When the mother liquor of lower H2O2 concentration has been discharged, there follows a sweating operation with a slow increase in temperature, as a result of which the H2O2 concentration in the crystal layer is increased further.

Abstract: A method for producing 2-(4-methyl-3-pentenyl)anthraquinone (IHEAQ) that includes a Diels-Alder addition of naphtho-1,4-quinone and myrcene and an oxidation of the resulting adduct. The oxidation step is carried out in the presence of a solvent mixture that contains a polar and a nonpolar solvent. The oxidation takes place with air or an O2-containing gas in the presence of a combination of a strong inorganic base and an organic, especially a nitrogen-containing base. The method leads to a higher space-time yield and higher product purity.

Abstract: A cyclic anthraquinone process for producing hydrogen peroxide using at least two differently substituted 2-alkylanthraquinones and/or their tetrahydro derivatives. The working solution to be used contains (i) at least one reaction carrier from the series 2-(4-methyl-3-pentenyl) anthraquinone (IHEAQ), 2-(4-methylpentyl) anthraquinone (IHAQ) and their di- and tetrahydro derivatives such as, in particular 2-(4-methylpentyl)-&bgr;-tetrahydroanthraquinone (THIHAQ), and (ii) at least one reaction carrier from the series of the 2-(C1- to C5)-alkylanthraquinones, especially 2-ethylanthraquinone (EAQ), and their tetrahydro derivatives. The reaction carriers according to (i) make up 5 to 95 molar %, especially 20 to 50 molar % of all reaction carrier. The method is distinguished by greater H2O2 capacity, improved hydrogenation kinetics and lesser susceptibility to disturbances. A method for making THIHAQ is also disclosed.