摘要:
A process for the production of a composite membrane, one or more microporous separation layers comprising a zeolite of the MFI type being produced by hydrothermal synthesis on a porous substrate, wherein one or more additives from the group consisting of linear (C1-C4)-alcohols, ammonia, primary, secondary and tertiary amines having in each case (C1-C4)-alkyl radicals, (C1-C4)-aminoalcohols and (C3-C4)-ketones are added to the synthesis solution for the hydrothermal synthesis.
摘要:
The invention relates to a process for the preparation of sodium dithionite, comprising the steps (a) provision of a synthesis batch comprising sodium formate, sulfur dioxide and an alkaline sodium compound in aqueous methanolic solution with formation of a sodium dithionite mother liquor, (b) isolation of sodium dithionite from the sodium dithionite mother liquor, a residual mother liquor being obtained, (c) separation of methanol from the residual mother liquor, (d) separation of the residual mother liquor into a thiosulfate-rich first part-stream and a thiosulfate-poor, formate-containing second part-stream by means of nanofiltration, (e) concentration of sodium formate in the second part-stream and (f) recycling of the concentrated second part-stream to process step (a).
摘要:
A process for producing a liquid formulation of salts of sulfonated azo dyes by coupling an at least equimolar amount of diazotized aminoarylsulfonic acids I H2N—Ar—SO3H (I), where Ar is phenylene (which may be monosubstituted by sulfo) or naphthylene (which may be mono- or disubstituted by sulfo and/or monosubstituted by hydroxyl) onto the coupling product of an unsubstituted or methyl-substituted phenylenediamine with itself comprises dissolving the azo dye in a basic medium and then subjecting the solution to a nanofiltration.
摘要:
The present invention relates to a process for preparing acrylic acid by two-stage heterogeneously catalyzed partial gas phase oxidation of propylene, in which the propylene source used is a preceding propane dehydrogenation and in which the first oxidation stage is operated with restricted propylene conversion, and unconverted propane and propylene present in the product gas mixture of the second partial oxidation stage are recycled substantially into the preceding propane dehydrogenation.
摘要:
The present invention relates to a process for preparing acrylic acid by two-stage heterogeneously catalyzed partial gas phase oxidation of propylene, in which the propylene source used is a preceding propane dehydrogenation and in which the first oxidation stage is operated with restricted propylene conversion, and unconverted propane and propylene present in the product gas mixture of the second partial oxidation stage are recycled substantially into the preceding propane dehydrogenation.
摘要:
A method for producing membranes which contain at least one solid layer on one side of a porous substrate by treating the side of the support, which is to be coated, with a synthetic solution that forms the solid layer. The inventive method is characterized in that the space located behind the side of the porous support, which is not to be coated, is filled with an inert fluid during the production of the solid layer on the porous support, “behind” being from the perspective of the support. The pressure and/or the temperature of the fluid is/are selected such that the synthetic solution is essentially prevented from entering in contact with the side of the porous support, which is not to be coated.
摘要:
A tray column is proposed which includes column trays, two or more supports which are arranged on the underside of the column trays and support them and a bearing ring for the column trays on the inner wall of the tray column, wherein three-way joints of inner column wall, bearing ring and support are prevented by cutouts in the bearing ring.
摘要:
A process for preparing at least one target product by partial oxidation and/or ammoxidation of propylene, in which the propylene source used is a propane dehydrogenation, the propane used therein being obtained by a rectificative prepurification of crude propane.
摘要:
A process for preparing acrolein or acrylic acid or a mixture thereof by heterogeneously catalyzed partial gas oxidation of propylene, in which the starting reaction gas mixture has the following contents: from 6 to 9% by volume of propylene, from 8 to 18% by volume of molecular oxygen, from 6 to 30% by volume of propane and from 32 to 72% by volume of molecular nitrogen.
摘要:
A process for heterogeneously catalyzed partial gas phase oxidation of propylene to acrylic acid in the absence of propane as an inert diluent gas, in which, in the starting reaction gas mixture, cyclopropane is substantially avoided as an impurity and crude propylene is used additionally as a propylene source.