摘要:
The present invention relates to a process for preparing (meth)acrylic esters (F) of N,N-substituted amino alcohols, by transesterifying N,N-substituted amino alcohols (I) in which Y and Z are each independently C1-C20-alkyl, C3-C15-cycloalkyl, aryl, or Y and Z together with the nitrogen atom connecting them form a 5- to 9-membered saturated heterocyclic radical which optionally has oxygen, sulfur, nitrogen or C1-C4-alkyl-substituted nitrogen as a further heteroatom, and X is C2-C20-alkylene which may be interrupted by 1 to 10 nonadjacent oxy groups and/or unsubstituted or methoxy-substituted C1-C4-alkylimino groups, or a C3-C15-cycloalkylene, with at least one (meth)acrylic ester (D) in the presence of at least one heterogeneous catalyst (K), wherein the heterogeneous catalyst (K) is used without any further solvent and the content of polymerization inhibitors in the reaction mixture is
摘要:
A process for removal of a crude acrylic acid from a product gas mixture which comprises glyoxal as a by-product from a heterogeneously catalyzed partial gas phase oxidation of at least one C3 precursor compound, which comprises the absorption of the acrylic acid in a high-boiling absorbent and the rectificative workup of the resulting adsorbate, and in which absorbent present in the bottoms liquid withdrawn from the bottom space of the absorption column is distilled off in a distillation unit and recycled into the absorption, before high boilers which remain are discharged, and in which the glyoxal content of the crude acrylic acid is reduced by restricting the high boiler residence time in the distillation unit.
摘要:
Method for stabilizing polyvinylpyrrolidones, which comprises treating the polyvinylpyrrolidones with sulfur dioxide, sulfurous acid or alkali metal sulfites and then with free-radical scavenger, and converting the solutions treated in this way into the powdered polyvinylpyrrolidones by drying.