Abstract: Novel 2-aminopyrazines and processes for the preparation of 2-aminopyrazines and pyrazines by reaction of an .alpha.-iminodiacetonitrile (a) with a hydrogen halide or (b) with an alcohol or a thioalcohol and a hydrogen halide or (c) with an alcohol or a thioalcohol in the presence of an alkali metal compound and/or an alkaline earth metal compound. The 2-aminopyrazines and pyrazines obtainable by the process of the invention are useful starting materials for the preparation of dyes, fungicides, bactericides, textile assistants, scents, folic acid derivatives, flavorings, and active ingredients in crop protection and drugs.

Abstract: Novel .alpha.-iminodiacetonitriles are prepared by a process in which an aldehyde-cyanohydrin or a haloacetonitrile is reacted with an aminonitrile, the reaction being carried out in the presence of a lower alkanol in the case of the preparation of symmetric .alpha.-iminodiacetonitriles, and in the presence of an auxiliary base in the case of the preparation employing a haloacetonitrile. The .alpha.-iminodiacetonitriles obtainable by the process of the invention are useful starting materials for the preparation of dyes, fungicides, bactericides, herbicides, textile assistants, anticorrosion agents, complex-forming agents, stabilizers in electroplating baths and inhibitors for antifreezes.

Abstract: Sludges are flocculated by the addition of a polymer which is prepared by the homopolymerization of N-vinylformamide in the presence of a free-radical polymerization initiator to give a poly-N-vinylformamide, followed by hydrolysis of from 10 to 90% of the formyl groups in the poly-N-vinylformamide.

Abstract: Linear basic polymers containing, as characteristic components, from 90 to 10 mole % of copolymerized units of the formula ##STR1## and from 10 to 90 mole % of copolymerized units of the formula ##STR2## are obtained by polymerizing the compound of the formula CH.sub.2 .dbd.CH--NH--CHO (N-vinylformamide) to a polyvinylformamide in the presence of a free radical polymerization initiator and splitting off the formyl group from the resulting polymer at from 20.degree. to 200.degree. in the presence of an acid or base. The reaction products are used as retention agents, drainage assistants and flocculants in papermaking.

Abstract: In a process for the preparation of aromatic monoaldehydes by reacting monochlorinated methylaromatics with hexamethylenetetramine by a Sommelet reaction, the improvement that in place of pure chloromethylaromatics the chlorination mixtures produced by photochlorination of the methylaromatics are employed and are treated with hexamethylenetetramine without prior working up, after which the Sommelet reaction is allowed to take place.