Abstract: In the production of granules containing anionic surfactants and having a bulk density above 450 g/l by granulation of a surfactant preparation containing a non-surface-active liquid component, the water demand and hence the energy demand for evaporating the water can be reduced if the anionic surfactant in its acid form or a mixture containing one or more anionic surfactants in their acid form and an aqueous alkaline solution are separately treated with a gaseous medium, subsequently sprayed in substantially stoichiometric quantities into the granulation and drying zone either separately or together under a high propellant gas pressure and then granulated and, at the same time, dried, optionally with addition of one or more inorganic or organic solids.

Abstract: In the production of light-colored pastes of .alpha.-sulfofatty acid alkyl ester alkali metal salts by reaction of fatty acid alkyl esters with gaseous SO.sub.3, subsequent after-reaction in liquid phase, neutralization with aqueous alkali metal hydroxide solutions and bleaching, effective bleaching can be obtained without any reduction in the washing-active substance content by addition of the hydrogen peroxide during neutralization of the .alpha.-sulfofatty acid alkyl ester and subjecting the neutralization product obtained to a temperature-controlled after-reaction.

Abstract: In the production of highly concentrated pastes of .alpha.-sulfofatty acid alkyl ester alkali metal salts by reaction of fatty acid alkyl esters with gaseous SO.sub.3, subsequent after-reaction in liquid phase and neutralization with aqueous alkali hydroxide solutions, the sulfonation product and aqueous alkali metal hydroxide solution are introduced during neutralization into an aqueous phase initially containing 0 to 55% by weight washing-active substance at a pH value in the range from 2 to 8 and washing-active substance contents of 60 to 70% by weight are established.

Abstract: In the production of .alpha.-sulfofatty acid alkyl ester alkali metal salt pastes by reaction of fatty acid alkyl esters with gaseous SO.sub.3, subsequent after-reaction in liquid phase and neutralization with aqueous alkali metal hydroxide solutions, the crude sulfonation product is fed to an at least two-stage cascade of stirred tanks equipped with heating and cooling systems in which it is subjected with mechanical agitation to a temperature-controlled after-reaction until a degree of sulfonation of at least 90% is reached, after which the aged sulfonation product is further processed in known manner to .alpha.-sulfofatty acid alkyl ester alkali metal salt pastes.

Abstract: In the production of highly concentrated pastes of .alpha.-sulfofatty acid alkyl ester alkali metal salts by reaction of fatty acid alkyl esters with gaseous SO.sub.3, subsequent after-reaction in liquid phase and neutralization with aqueous alkali hydroxide solutions, the sulfonation product and aqueous alkali metal hydroxide solution are introduced during neutralization into an aqueous phase initially containing at least 55% by weight washing-active substance at a pH value in the range from 2 to 8 and washing-active substance contents of 60 to 70% by weight are established.

Abstract: A process for the production of solid or paste-form products by fast reactions is carried out stoichiometrically wherein a gaseous medium is introduced into each of the reactants to be reacted with one another, the reactant streams formed are combined and are subsequently forced through a spray unit in a weight ratio of gaseous medium to product stream of from 0.04 to 0.3 (kg/kg) and at a rate of 0.1 to 15 m/second, as calculated from the gas-free reactant streams and based on the free cross-section of the spray unit. The products obtained are free from readily volatile constituents.

Abstract: In light colored surfactants produced by sulfonation of fatty acid alkyl esters with less than 2 moles of SO.sub.3 per mole of fatty acid alkyl ester and subsequent work-up of the crude sulfonate in aqueous medium to form salts, the content of .alpha.-sulfofatty acid disalts is regulated and reduced by transesterifying the sulfonation product before its treatment with an aqueous medium with at least about 0.5 mole equivalent of an alcohol, based on the SO.sub.3 which is not for .alpha.-sulfonation.

Abstract: In light colored surfactants produced by sulfonation of fatty acid alkyl esters with less than 2 moles of SO.sub.3 per mole of fatty acid alkyl ester and subsequent work-up of the crude sulfonate in aqueous medium to form salts, the content of .alpha.-sulfofatty acid disalts is regulated and reduced by transesterifying the sulfonation product before its treatment with an aqueous medium with at least about 0.5 mole equivalent of an alcohol, based on the SO.sub.3 which is not for .alpha.-sulfonation.