Abstract: The invention relates to a process for the preparation of acesulfam salts by reaction of salts of amidosulfonic acid with diketene to give a salt of acetoacetamidosulfonic acid (I), ring closure by the action of at least about an equivalent amount of SO.sub.3, at least this ring closure reaction being carried out in the presence of a halogenated, aliphatic hydrocarbon as an inert solvent, treatment of the cyclization product with water and conversion of the resulting acesulfam-H (II) into the form of a non-toxic salt, which comprises, in the work-up by distillation of the resulting crude solvent, after removal of water and low-boilers and recovery of solvent sufficiently pure for reuse in the preparation of compounds (I) and/or (II), directly returning :he remaining, solvent-containing distillation residue, without further purification, into the system downstream of the reaction vessel for carrying out the ring closure reaction.

Abstract: Process for the recovery of catalyst in the production of ether carboxylic acids by catalytic oxidation with a suspended ether catalyst in which the reaction mixture is subjected to cross-flow filtration.

Abstract: Process for the continuous preparation of dialkyl vinylphosphonates using catalysts at temperatures of from 150.degree. to 270.degree. C. by dissociation of dialkyl acetoxyethanephosphonates at a pressure of from 5 to 500 mbar in contact with a liquid, catalytically active medium while drawing off the dialkyl vinylphosphonates formed and other volatile reaction products as vapors, by conveying the liquid medium in forced circulation via an evaporator while feeding in fresh dialkyl acetoxyethanephosphonate, if desired admixed with catalyst, corresponding to the distillation of dialkyl vinylphosphonates and other volatile compounds, and drawing off non-volatile material formed as byproduct from the liquid circuit to maintain constant conditions.