P.S. Plaza’s scientific contributions

In this contribution the life and work of François-Antoine-Henry Descroizilles is reviewed. He is recognized as a multifaceted person, and as a skilled and wise chemist by eminent scientists of his time. Descroizilles developed his professional career as a chemistry teacher, apothecary, and industrial chemist, contributing firstly to give a solution to the latent problem of cider in Normandy, and to the bleaching of tissues by the new method of Berthollet in the area of Rouen later. He proposes on this respect a (redox) titrimetric method of determining the concentration of chlorine, Gordian knot of the problem. Descroizilles can rightly on this way be considered as the father of titrimetric analysis, but his ingenuity goes much further, and his name can be associated to a variety of inventions. In the approach that is carried out here, emphasis is previously placed on the context of the new chloric bleaching, aspect that might not be always treated with enough depth in previous papers on Descroizilles. In the first part of this paper the boundary conditions of this topic will be located and studied, in a time, in which the intent of the study of the chemical arts rapidly acquires great importance. The development of the chlorine bleaching industry is influenced by the technical aspects of the processes involved, but also by the social and economic factors. Aspects of the life and work of Descroizilles, including topics such as the problem of cider, inventions, bleaching power and alum, as well as the contributions of Gay Lussac to titrimetry will be the subject of a future report (second part).

A brief on bleaching and alkalis is given previous to the life and contributions of Francis Home and William Lewis, pharmaceutical profile authors. The relevance of their work and the worth of their publications are revealed. Chemistry and practice go hand in hand in the development of these issues.

A brief account of the worth and history of two relevant reactions, the dichromatometric oxidation of ethanol and phenol bromination is attempted in this paper. Titrimetric analyses of ethanol and phenol are outlined.

Under the background of the iodometric methods we analyze the life and work of two great Hungarian scientists, Than and Winkler, teacher and disciple. They were responsible for the introduction of scientific chemistry and pharmaceutical education in his country, which moved in the orbit of the Austro-Hungarian Empire. Both generated a school of excellence in the academic field. Than contributes among many other discoveries to the use of potassium biiodate for the standardization of sodium thiosulfate and Winkler develops an iodometric method for the determination of dissolved oxygen in waters, a classic of chemical analysis, the use of which continues today. The use of potassium dichromate by Zulkovsky opened the possibility to the analytical applications of the oxidations with dichromate in iodometry. The iodide, bromide and iodine index determinations, make the analytical chemistry of halogens a distinctive branch of Hungarian science. Schulek, a disciple of Winkler, opens the door to the development of pharmaceutical analysis and the pharmaceutical industry in Hungary.