Abstract: A process for preparation of a compound with enhanced optical purity is disclosed wherein a mixture of the enantiomers of a chiral amine is brought into contact with an enzyme having peptide deformylase activity with a bivalent metal ion as a cofactor.

Abstract: Finely divided precipitated silica with high structure and a______________________________________ BET surface (DIN 66 132) of 150 to 350 m.sup.2 /g Stamping density (DIN 53 194) between 60 and 120 g/l DBP number between 3.0 and 4.0 ml/g Particle size distribution at least 70% from 1 to 6 .mu.m ______________________________________can be prepared by heating a mixture of water and sodium silicate under agitation to a temperature of 70.degree. to 80.degree. C., adding concentrated sulfuric acid into this mixture until half of the alkali present has been neutralized, shearing the reaction mixture and optionally raising the temperature at the same time to 86.+-.5.degree. C. Concentrated sulfuric acid is added after a period of 30 to 120 minutes at a rather high rate until the pH of the silica suspension produced is 3.0 to 3.

Abstract: Finely divided precipitated silica for use as a delustering agent with high structure and a______________________________________ BET surface (DIN 66 132) of 150 to 350 m.sup.2 /g Stamping density (DIN 53 194) between 60 and 120 g/l DBP absorption number between 3.0 and 4.0 ml/g Particle size distribution at least 70% from 1 to 6 .mu.m ______________________________________ can be prepared by heating a mixture of water and sodium silicate under agitation to a temperature of 70.degree. to 80.degree. C., adding concentrated sulfuric acid into this mixture until half of the alkali present has been neutralized, shearing the reaction mixture and optionally raising the temperature at the same time to 86.degree..+-.5.degree. C. Concentrated sulfuric acid is added after a period of 30 to 120 minutes at a rather high rate until the pH of the silica suspension produced is 3.0 to 3.5.

Abstract: Aerogel like silica is prepared having:A BET surface area between 80-450 m.sup.2 /g;A bulk density between 10-60 g/l;A DBP number between 2.4-3.8;An average particle size range of 0.1-7 .mu.m;A most frequent particle size range of 1-2 .mu.m;A pH value in a 4% aqueous suspension of 6-8.The aerogel is produced by homogeneously distributing 5-50 weight % of water in air dispersed pyrogenic silica and drying the powdery mixture obtained. The products are especially useful as delustering agents.