摘要:
A process for preparing a hydrogen peroxide solution having a hydrogen peroxide content of not less than 2.5% by weight, which comprises continuously reacting hydrogen and oxygen in an aqueous, alcoholic or aqueous/alcoholic reaction medium in the presence of a catalyst containing palladium.
摘要:
A process for oxidizing an organic compound having at least one C—C double bond or a mixture of two or more thereof comprises the following steps: (I) preparing a hydroperoxide, (II) reacting an organic compound having at least one C—C double bond or a mixture of two or more thereof with the hydroperoxide prepared in step (I) in the presence of a zeolite catalyst, (III) regenerating the at least partially deactivated zeolite catalyst used in step (II), and (IV) conducting the reaction of step (II) using a zeolite catalyst containing the catalyst regenerated in step (III).
摘要:
The invention relates to a method for producing catalysts by immersion coating a metallic support with at least one platinum metal. An aqueous medium which comprises at least one platinum metal complex, at least one reduction agent and at least one complexer and which has a pH value of more than 4 is brought into contact with the metallic support in order to deposit the platinum metal, the platinum metal being deposited in the form of discreet, immobilised particles. The invention also relates to the catalysts obtained using this method and to their use for producing hydrogen peroxide and for hydrogenating organic compounds.
摘要:
Disclosed are a highly pure aqueous hydrogen peroxide solution for use in the electronics industry and a process for the preparation of such solutions, which are essentially free from organics, which comprises catalytically converting hydrogen and oxygen, electrochemically reducing oxygen or electrolyzing an acidic ammonium sulfate solution, in each case in water and with the exclusion of organic compounds and materials which release such compounds.
摘要:
A structured packing for heat exchange and mass transfer between a liquid and a gas in a column having at least one packing layer with a first, lower end and a second, upper end is described, the packing layer having an internal geometry which varies over its height so that by suitably setting the liquid and gas flow rates in a first, in particular lower, region of the packing layer a bubbling layer having a predominantly disperse gas phase forms in a targeted manner and simultaneously in a second, in particular upper, region of the packing layer a film flow of the liquid having a predominantly continuous gas phase forms in a targeted manner.
摘要:
A process is proposed for the distillation or reactive distillation of a mixture that includes at least one toxic component, the process being carried out in a column containing a structured packing, having at least one packing layer (1) having a lower end (2) and an upper end (3), the packing layer having an internal geometry varying over its height, in such a manner that in the distillation or reactive distillation, in a first, lower region (6) of the packing layer (1) a bubbling layer having a predominantly disperse gas phase can be established and simultaneously in a second, upper region (7) of the packing layer (1) a film flow having a predominantly continuous gas phase can be established.
摘要:
The invention relates to a packing sheet having straight-line kinks which divide the packing sheet into kink areas which have a width a, measured from kink edge to kink edge, and passage apertures, where a proportion X of at least 60% of the passage apertures has a separation b of at most 0.4 a from a kink edge.
摘要:
Process for producing polyamides that are stable during processing, by treating the polyamide during the solid-phase postcondensation process with a gas which comprises carrier gas (inert gas), water, and acid, or an anhydride or lactone or a mixture of these or, respectively, comprises ammonia, or amine, or a mixture of these, at a temperature from 130 to 200° C. and at a pressure of from 0.01 to 10 bar.
摘要:
A process for preparing water-absorbing polymer beads by polymerizing droplets of a monomer solution in a gas phase surrounding the droplets, the initiator being added to the monomer solution from 0.5 to 60 seconds before the droplets are generated.
摘要:
A process for removing trioxane from a mixture I of formaldehyde, trioxane and water, by a) distilling the mixture I in a first distillation stage at a pressure of from 0.1 to 2 bar to obtain a stream II which comprises formaldehyde and a stream III which comprises predominantly trioxane and additionally water and formaldehyde, b) mixing the stream III with a recycle stream VII which comprises predominantly trioxane and additionally water and formaldehyde to obtain a stream IIIa which comprises predominantly trioxane and additionally water and formaldehyde, c) distilling the stream IIIa, if appropriate after removing low boilers from the stream III or IIIa in a further distillation stage, in a second distillation stage at a pressure of from 0.2 to 10 bar, the pressure in the second distillation stage being at least 0.1 bar higher than the pressure in the first distillation stage, to obtain a stream IV of trioxane and a stream V which comprises predominantly trioxane and additionally water and formaldehyde, d) distilling the stream V in a third distillation stage at a pressure of from 0.1 to 4 bar to obtain a stream VI which comprises predominantly water and additionally formaldehyde, and the recycle stream VII which comprises predominantly trioxane and additionally water and formaldehyde, e) if appropriate, distilling the stream VI in a fourth distillation stage to obtain a stream VIII which comprises predominantly water, and a stream IX which comprises predominantly formaldehyde.