Thomas Graham. II. Contributions to diffusion of gases and liquids, colloids, dialysis, and osmosis

AbstractIn this second part, the contributions of Thomas Graham in the areas of diffusion and transfer of gases and liquids through membranes are discussed

Four brilliant students of Henri Sainte-Claire Deville 4. Alfred Ditte

AbstractAlfred Ditte (1843–1908), a student of Henri Sainte-Claire Deville, carried on a large number of important researches in the areas of mineralogy, chemistry, and thermodynamics, in particular, vanadium and its compounds, properties of aluminum, alumina, and aluminates, the Leclanché cell, dissociation mechanism, and iodic acid and iodates

Four Brilliant Students of Henri Sainte-Claire Deville 1. Henri Jules Debray

AbstractHenri Jules Debray (1827-1888), a student of Henri Sainte-Claire Deville, carried on a large number of important researches in the areas of mineralogy, crystallization, synthetic reproduction of natural crystals, preparation of beryllium and its salts, and particularly, in the metallurgy, preparation of the pure metals, and synthesis of derivatives of the metals of the platinum group

JULIEN-JOSEPH VIREY

Jean-Joseph Virey (1775-1846) was a French physician and naturalist to whom we owe a systematic study of the relation between the color of a medicine and its action, the color of flowers and other parts of the plant as a distinguishing property, and the odors of different substances. The colors of vegetables indicated, in general, their dominant principles and could serve to establish the difference in medical matter. The odors of different natural substances, and particularly those of medicines, constituted an essential part of their properties. Odors acted upon the different systems of a body and operated on humans like medicines. Virey believed that the aphrodisiac dudaim of the Bible were an orchid, probably one of those from which the salep was prepared. Plants were able to experience impressions of excitability from light, heat, dry or humid air, electricity, and other surrounding agents. Vegetable and animal poisons usually operated on living organisms and according to the organization mode of the species upon which they acted; they could became food, medicine, or poison to the entities that absorbed them. The production of a gall was a clear manifestation of the irritability of the tissue of vegetables, analogous to the bite of the insect, which deposited an acrid and stimulating poison on the wound of an animal. Virey speculated on the effect of cold on organized organisms in general and on the wonderful art that nature appropriated these beings to the coldness of the poles or to the equatorial ardor, to assure their subsistence

LOUIS BOUVEAULT

Louis Bouveault (1864-1909), a French chemist and physician who found that the action of sodium upon nitriles resulted in the formation of monosodium derivatives where the sodium atom was attached to the carbon atom closest to the group -CN.  He studied in detail the synthesis of many new compounds, among them, b-ketone nitriles, primary alcohols, fatty acids, etc. His most important contribution is the Bouveault synthesis of aldehydes, a one-pot substitution reaction that replaces an alkyl or aryl group with a formyl using a disubstituted formamide. He illustrated his reaction by preparing valeraldehyde, benzaldehyde, decyl aldehyde, etc.  He studied in detail the separation and properties of numerous plant extracts, among them, rhodinol, rhodinal, lemon grass, lemonals, citronellol, etc. The oxime of citronellal, a stable aldehyde, acted by acetic anhydride, yielded the corresponding nitrile. Bouveault and Gourmand carried the total synthesis of rhodinol

AUGUSTIN-PIERRE DUBRUNFAUT

Augustin-Pierre Dubrunfaut (1797-1881) was a French industrialist and chemist to whom we owe the discovery of mutarotation, d-fructose and maltose, the true nature of invert sugar, the mode of action of diastase and invertase, the application of osmosis to the purification sugar, the large-scale manufacture of ethanol from sugar beets, etc. Dubrunfaut used the Soleil polarimeter to discover the change of the rotatory power of aqueous glucose with time and temperature and to prove that invert sugar was composed of one-half of an equivalent of dextro monorotatory glucose and one-half equivalent of levo liquid sugar (levulose), which could be separated by simple procedures. He demonstrated that lactose also presented the phenomenon of mutarotation. Dubrunfaut analyzed in detail the phenomenon of osmosis, discovered by Dutrochet, and proved that dialysis was a special case of it. This claim brought a bitter discussion with Thomas Graham. He showed that exosmosis could be used to purify sugar very simply. Dubrunfaut claimed that malt diastase was a mixture of compounds, which included the real agent (maltose) altered or modified. Maltose could be economically fabricated in a brewery by precipitation with tannin. He also studied in detail the carbohydrate inuli

Ascanio Sobrero

Ascanio Sobrero (18121888), inicialmente educado como médico, fue uno de los más consumados químicos Italianos de su época. Se le recuerda en forma especial por haber descubierto la nitroglicerina, su poder explosivo y su uso como vaso dilatante. Alfred Nobel transfomaría la nitroglicerina en dinamita y daría nacimiento a la industria moderna de los explosivos. Sobrero realizó importantes investigaciones sobre los productos obtenidos por destilación de resinas y aceites esenciales; como resultado de una de ellas, descubrió el hidrato de pirrolo (sobrerol), que sigue siendo usado hoy en día para el tratamiento de afecciones bronquiales

Nicolas Leblanc . Chemical revolution and social injustice

The development of soda ash as part of the heavy chemical industry is closely linked with the chemical revolution that took place in the eighteenth and nineteenth centuries. Strong political and economic reasons led to the search for synthetic procedures to replace the natural sources of carbonates that had been available since the seventeenth century. In 1789 Leblanc developed a synthetic process using common salt as raw material and made available to France and the world whole a discovery of undeniable usefulness. Strong political events prevented Leblane from receiving adequate compensation; the following generations were the great beneficiaries of its discovery

Antoine-Jerôme Balard. The discoverer of bromine

To Antoine-Jerôme Balard (1802-1876) we owe the discovery of bromine, oxamic acid, hypochlorous acid, and chlorine monoxide, and of having been the mentor of Pasteur and Berthelot. The process that he developed for the production large quantities of bromine is basically the same that is nowadays used in the industrial manufacture of the element

JEAN-CHARLES GALISSARD DE MARIGNAC Physical and organic chemistry, atomic masses, and rare earths

Jean-Charles Galissard de Marignac (1817-1894) was a Swiss chemist who investigated the derivatives of naphthalene with nitric acid and synthesized and described the properties of  nitronaphthalic acid, trinitronaphthalene, nitronaphthalese, naphthalamide, and a series of naphthalates. Marignac extended the work of Schönbein about the nature and properties of ozone and proved that the gas did not contain nitrogen although he was unable to decide if ozone was composed of pure oxygen or oxygen and hydrogen. He also developed a simple procedure for producing concentrated sulfuric acid by the partial crystallization of the acid at low temperatures, determined that at high temperatures ammonium chloride decomposed into ammonia and hydrogen chloride, and studied the thermal properties of liquids (specific heat, density and expansion) particularly of aqueous solutions of halides nitrates, sulfates, chromates, carbonates, acetates, oxalates, and phosphates. His most important contribution was the careful determination of the atomic mass of a large number of elements. He investigated the rare earths and discovered gadolinium and ytterbium (although he did not separate them from their oxides), purified terbium, etc