Abstract: A process for the preparation of alkyleneimines by subjecting sulfuric acid monoesters of aminoalkanols to an at least two-stage reaction with aqueous bases at a temperature of at least 110° C. under pressure, relieving the pressure of the reaction mixture and distilling off the alkyleneimines from the reaction mixture after each reaction stage, wherein the conversion in the first stage is from 40 to 90% and that in the second stage is from more than 90% to 99.99%.

Abstract: A process for the preparation of alkyleneimines by subjecting sulfuric acid monoesters of aminoalkanols to an at least two-stage reaction with aqueous bases at a temperature of at least 110° C. under pressure, relieving the pressure of the reaction mixture and distilling off the alkyleneimines from the reaction mixture after each reaction stage, wherein the conversion in the first stage is from 40 to 90% and that in the second stage is from more than 90% to 99.99%.

Abstract: The present invention relates to an improved process for preparing riboflavin of the B/C modification in granule form. Furthermore, the invention relates to the riboflavin preparation process wherein riboflavin of the A modification is (a) dissolved in aqueous mineral acid without treating the resulting riboflavin solution with activated carbon, (b) precipitated directly afterwards, steps (a) and (b) being carried out at a temperature in the range from 5 to 15° C., and (c) dried by fluidized bed granulation; and wherein the riboflavin does not come into contact with the aqueous mineral acid solvent for longer than on average 4 hours.

Abstract: The present invention relates to an improved process for preparing pure riboflavin (vitamin B2) of the B/C modification in granule form. Furthermore, the invention relates to pure riboflavin in granule form which has a bulk density to be determined in accordance with DIN 53468 of from 0.45 to 0.7 g/ml and, after tableting, has a dissolution of at least 80%.