Abstract: Process for the continuous preparation of prepolymers based on phenolic resin, an oxazoline component and an epoxide in the presence of a catalyst, including supplying the phenolic resin and the oxazoline component to an extruder in a stream A; a Lewis adduct of boron trifluoride or of aluminum trichloride, or arylsulphonic acids or alkylsulphonic acids, or latent arylsulphonic acids or latent alkylsulphonic acids, in a stream B, and the epoxide in a stream C, the infeed of stream A being situated, as seen in extrusion direction, before the infeed of stream C, these reactants are mixed at a reaction temperature of 120 to 200° C. with a residence time in the extruder of 3 seconds to 15 minutes, and then the product discharge of the extruder is cooled to a temperature of less than 45° C. within from 30 to 60 seconds.

Abstract: A hardener system for epoxy resins comprising i) at least one aromatic dianhydride compound A having a melting point of at least 35° C., ii) at least one monoanhydride compound B having a melting point of not more than 30° C. and iii) at least one catalyst C, is provided. The aromatic dianhydride compound A is dispersed in the hardener system. The present invention further provides for the use of said hardener systems and to processes for hardening epoxy resin systems.

Abstract: Process for the continuous preparation of prepolymers based on phenolic resin, an oxazoline component and an epoxide in the presence of a catalyst, including supplying the phenolic resin and the oxazoline component to an extruder in a stream A; a Lewis adduct of boron trifluoride or of aluminium trichloride, or arylsulphonic acids or alkylsulphonic acids, or latent arylsulphonic acids or latent alkylsulphonic acids, in a stream B, and the epoxide in a stream C, the infeed of stream A being situated, as seen in extrusion direction, before the infeed of stream C, these reactants are mixed at a reaction temperature of 120 to 200° C. with a residence time in the extruder of 3 seconds to 15 minutes, and then the product discharge of the extruder is cooled to a temperature of less than 45° C. within from 30 to 60 seconds.

Abstract: A process for the preparation of alkoxyalkylidenemalonic acid esters. The reaction is catalyzed by easily separable, insoluble aluminum silicates.

Abstract: Cytosines which may optionally be substituted in the 5 position are prepared by a simplified process in which urea is reacted with an alcoholate and an alkoxy-acrylonitrile or dialkoxy-propionitrile in a sparsely water-miscible organic solvent which is inert under the reaction conditions. The use of such a solvent makes it possible to react the mentioned reactants in simple fashion without isolation of an intermediate stage, and to reuse the organic solvent without a separate purification.