Abstract: A process for the production of tetrabromo-4,4'-alkylidenediphenols, especially tetrabromobisphenol A (TBBA), from the corresponding alkylidenediphenols by oxidative bromination with Br.sub.2, HBr.sub.3 or HBr and aqueous hydrogen peroxide in the presence of an organic solvent. The process is characterized by washing the organic phase containing dissolved tetrabromo-4,4'-alkylidenediphenol with an aqeuous alkali sulphite solution, preferably at 50.degree. to 90.degree. C. Through this washing treatment, the tetrabromo compound is obtained in higher purity; in addition, the mother liquor can be recycled without difficulty.

Abstract: The known hydrocyanic acid-methane-ammonia (BMA) process for the production of hydrogen cyanide can now be carried out with liquified gases namely through the presence of additional hydrogen at the beginning of the reaction. The atomic ratio of carbon to nitrogen and hydrogen is from 1:1:7.1 to 1:1.33:13. As additional hydrogen there is the portion of hydrogen present coming out of the reaction "hydrocarbon+NH.sub.3 ". Otherwise the reaction conditions are the same as in the known BMA process.

Abstract: 4,4'-isopropylidene-bis(2,6-dibromophenol) is produced by reacting 4,4'-isopropylidene diphenol with hydrogen bromide or a mixture of hydrogen bromide with up to an equimolar amount of free bromine in admixture with hydrogen peroxide and in the presence of water and an inert organic liquid.