Abstract: Herbicidally active compounds of the formula ##STR1## in which .sup.1 represents a hydrogen or chlorine atom,R.sup.2 represents a hydrogen atom, a cyano group, an optionally substituted radical selected from alkyl, aryl, alkanoyl, benzoyl, alkoxycarbonyl, alkenoxycarbonyl, alkinoxycarbonyl, aralkoxycarbonyl and aryloxycarbonyl, or a radical of the general formula --COOM,in whichM represents a hydrogen atom, one equivalent of an alkali metal ion or alkaline earth metal ion or optionally substituted ammonium, andR.sup.3 represents a cyano group or a radical of the general formula ##STR2## wherein Y represent an oxygen or sulphur atom or an imino (NH) or alkylimino (Nalkyl) group,R.sup.4 and R.sup.5 independently of each other represent a hydrogen atom or a methyl group,n is 0 or 1 andZ represents an optionally substituted radical.Novel intermediates therefor are also shown.

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.