Abstract: Crystalline zirconium oxide powder with a BET surface of less than 30 m.sup.2 /g, preferably 10 to 20 m.sup.2 /g, a primary particle size of 0.1 to 0.5 .mu.m, a monoclinic crystal structure and, optionally, a content of Y.sub.2 O.sub.3 of 1 to 10% by weight and/or of 1 to 10% by wt. MgO.It is produced by adding an aqueous zirconium salt solution optionally containing yttrium ions and/or magnesium ions under agitation into a vessel which contains an aqueous base solution such as e.g. sodium hydroxide solution with a content of NaOH which corresponds to an excess of at least 0.5 mole/l NaOH. The mixture obtained in this manner is then treated hydrothermally at a temperature of 200.degree. to 400.degree. C., the product obtained is separated by filtration, washed chloride-free with water and dried at 100.degree. to 120.degree. C.The zirconium oxide powder can be used to produce sintered ceramics.

Abstract: The invention is directed to a process for hte production of water insoluble peroxycarboxylic acids in which the carboxylic acid is suspended in the reaction mixture and reacted with hydrogen peroxide in the presence of pyridine-2,6-dicarboxylic acid.

Abstract: A radiation-hardenable agent for the scratch-resistant coating of organic glasses consists of a cocondensate of vinyl trimethoxysilane or vinyl triethoxysilane and tetramethoxysilane or tetraethoxysilane, a reactive diluent which comprises at least 2 vinyl, acrylic or methacrylic groups per molecule and, if necessary, of a known photoinitiator. The agent can be prepared by forming the cocondensate in the presence of an amount of water which is at least equivalent to the methoxy or ethoxy groups present or in the presence of a small amount of a carboxylic acid, removing all volatile portions of the reaction mixture and mixing the oily siloxane remaining as residue with the other components.

Abstract: Salts of N-acetyl cysteine and N-acetyl homocysteine are prepared by reacting acetonitrile with cysteine or homocysteine in an aqueous or aqueous-organic medium adjusted to a pH in the range of 8 to 10 with a base supplying the cation of the salt. The reaction is carried out at a temperature in the range of 0.degree. C. to the boiling temperature of the reaction mixture.

Abstract: There are employed as biocides for aqueous systems water soluble low molecular weight polycondensation products which are produced from acrolein and formaldehyde in the molar ratio between 1:1 and 1:10 in aqueous or aqueous-organic medium in the presence of a basic catalyst. The condensation reaction can also be carried out in the additional presence of water soluble mono- or polyhydric alcohols and/or acid amides.