Ruthenium explosive

Ruthenium is a hard, white metal and has four crystal modifications. It does not tarnish at room temperatures, but oxidizes explosively. It is attacked by halogens, hydroxides, etc. Ruthenium can be plated by electrodeposition or by thermal decomposition methods. The metal is one of the most effective hardeners for platinum and palladium, and is alloyed with these metals to make electrical contacts for severe wear resistance. A ruthenium-molybdenum alloy is said to be... 

Ruthenium is insoluble in aqua regia, but addition of potassium chlorate causes explosive oxidation. 

Reaction with the acid to give ruthenium triiodide is explosively violent. 

Dissolution of a zinc-ruthenium alloy in hydrochloric acid leaves an explosive residue of finely divided ruthenium [1], More probably this is the hydride, which may decompose on slight stimulus, the evolved hydrogen probably igniting because of the catalytic activity of the metal. Ruthenium prepared from its compounds by borohydride reduction is especially dangerous in this respect [2],... 

There is much current excitement and activity in the field of homogeneous hydrogenation using ruthenium catalysts. This is reflected in the recent, explosive increase in the number of research publications in this area, now rivaling those for rhodium catalysts (Fig. 3.1). Meanwhile, the price of rhodium metal has risen dramatically, becoming about ten times that of ruthenium, on a molar basis. The number of reports on the use of osmium catalysts has remained low, partly because of the higher price of osmium compounds - about ten times that of ruthenium - and partly because the activity of osmium catalysts is often lower. 

The main hazard is the explosiveness of ruthenium fine power or dust. The metal will rapidly oxidize (explode) when exposed to oxidizer-type chemicals such as potassium chloride at room temperature. Most of its few compounds are toxic and their fumes should be avoided. 

The electrolytic cells shown in Figures 2—7 represent both monopolar and bipolar types. The Chemetics chlorate cell (Fig. 2) contains bipolar anode/cathode assemblies. The cathodes are Stahrmet, a registered trademark of Chemetics International Co., and the anodes are titanium [7440-32-6]y Ti, coated either with ruthenium dioxide [12036-10-1]y Ru02, or platinum [7440-06-4], Pt—iridium [7439-88-5]y Ir (see Metal anodes). Anodes and cathodes are joined to carrier plates of explosion-bonded titanium and Stahrmet, respectively. Several individual cells electrically connected in series are associated with... 

Ruthenium tetraoxide is a powerful oxidant it is more reactive than osmium tetraoxide, and combines explosively with ether or benzene, so that it is generally used as a dilute solution in carbon tetrachloride. Beynon et al.155 first demonstrated the usefulness of this reagent in carbohydrate chemistry by converting methyl 4,6-0-benzylidene-2-deoxy-a-D-n bo- and -D-uraZu rao-hexopyranosides into methyl 4,6-0-benzylidene-2-deoxy-a-D-eryt/zro-hexopyranosid-3-ulose. 

Recent studies1,2 have shown the azido-pentaammineruthe-nium(III) species to be very unstable toward decomposition to pentaammine(nitrogen)ruthenium(II). Unlike [Ru(NH )s-(N3)]2+, the a s-[Ru(en)2(N )2]+ cation is moderately stable at room temperature, and its isolation is described below. Heating a s-[Ru (en) 2 (N8) 2]PF in the solid state provides a rapid and efficient preparation of cis-[Ru(en)2(N2)(Ni)]PF6. Caution. All azides are potentially explosive and should he handled with care. 

As far as we are aware the first example of a ruthenium(II)-arene compound to be evaluated for anticancer activity was described by Tocher and co-workers in 1992 [18]. The field remained essentially dormant until the explosion in interest led largely by our group and that of Sadler, who has extensively studied ruthenium(II)-arene complexes with ethylenediamine and related ligands, and describes these compounds in the Chapter X in this book. It should be noted that other groups have also contributed to the field as will become clear in the course of this Chapter. 

Recently, a ruthenium-catalysed oxidation in water was published by d Alessandro et al. [34]. Water can be regarded as an environmentally friendly solvent which, because it is inert, reduces the risk of explosions. The oxidation of cyclohexane directly to adipic acid was performed using ruthenium catalysts bearing water-soluble phthalocyanine ligands RuPcS (where PcS is tetra-sodium 2,3-tetrasulfophthalocyaninato) with KHSOs (Eq. 4). However we note that very low TONs were observed and the use of KHSOs as a primary oxidant is not viable for industrial-scale oxidations. 

This monograph is not intended to provide a comprehensive view of all ruthenium-catalyzed reactions, as it is an explosive growth field. For instance, ruthenium-catalyzed enantioselective hydrogenation, already detailed in several monographs, will not be treated here in spite of its high impact in organic synthesis. 

Ruthenium, rhodium, iridium and platinum are characterised by yielding, upon reduction of their salts, highly explosive powders. Osmium and palladium do not appear to share this property.3... 

It is important to ensure oomplete solution of the ruthenium tetroxide, otherwise the addition of aloohol causes reactions to take place with explosive violence (Howe, J. Amer. Chem. Soc., 1901, 23, 775 j Gutbier and Trenkner, loc. dt.). 

Explosive Ruthenium is obtained by dissolving an alloy of the metal with excess of zinc in hydrochloric acid. The zinc passes into solution, leaving metallic ruthenium as a finely divided, explosive residue. Unlike rhodium and iridium, ruthenium is explosive even when prepared in the entire absence of air. It seems hardly possible, therefore, that the same explanation for the explosivity can apply as for the first two metals (see pp. 156, 239). Perhaps Bunsen s original explanation is the correct one, namely, that an unstable modification or allotrope is first formed, and that this is converted into the stable variety with considerable heat evolution.7... 

Ruthenium tetroxide dissolves to a slight extent in water. It is also soluble in caustic alkali, from which solutions a black precipitate of finely divided ruthenium is obtained on addition of alcohol.2 Both the aqueous solution and the pure substance itself possess an odour resembling that of ozone. Its vapour, however, is not poisonous like that of the corresponding tetroxide of osmium. In contact with alcohol the solid tetroxide is reduced with explosive violence.3-4 When covered with water, to which a concentrated solution of caesium chloride is subsequently added and a little hydrochloric acid, ruthenium tetroxide is gradually converted into the oxy-salt, Cs2Ru02CI4. The corresponding rubidium salt has likewise been prepared.3... 

A very dangerous fire and moderate explosion hazard when exposed to heat or flame can react vigorously with oxidizing materials. Warning pyrophoric in air. Mixtures with nitrogen oxide explode above 50°C. Violent reaction with zinc + transition metal halides (e.g., cobalt halides, rhodium halides, ruthenium halides). Mixtures with acetic acid + water produce a pyrophoric powder. To fight fire, use water, foam, CO2, dr " chemical. See also CARBONYLS and IRON COMPOUNDS. 

A powerful oxidizer and very reactive material. It has been the cause of many industrial explosions. May explode on heating. Explosive reactions with ammonium chloride, aqua regia + ruthenium, sulfur dioxide solutions in ether or ethanol. Reacts with fluorine to form the explosive gas fluorine perchlorate. 

SAFETY PROFILE Most ruthenium compounds are poisons. Ruthenium is retained in the bones for a long time. Flammable in the form of dust when exposed to heat or flame. Violent reaction with ruthenium oxide. Explosive reaction with aqua regia + potassium chlorate. When heated to decomposition it emits very toxic fumes of RuOx and Ru, which are highly injurious to the eyes and lung and can... 

Ignites in air above 288°C when exposed to spark. Potentially explosive reaction with aluminum chloride -I- bis(2-methoxyethyl) ether. Reacts with ruthenium salts to form a solid product which explodes when touched or on contact with water. Reacts to form dangerously explosive hydrogen gas on contact with alkali, water and other protic solvents (e.g., methanol, ethanol, ethylene glycol, phenol), aluminum chloride -I- bis(2-methoxyethyl)ether. Reacts violently with... 

This triad of elements have played a crucial role in the development of the chemistry of 2,2 -bipyridine. The characteristic red color of [Fe(bpy)3l + was first observed by Blau in his pioneering studies on 2,2 -bipyridine (73-75), and iron complexes of bpy have continued to be of interest in the past century. The complexes of iron, ruthenium, and osmium probably account for about a third of all literature references to 2,2 -bipyridine complexes. This in part represents the facile synthesis of the complexes, their high stability, and extensive redox chemistry. The recent interest in the use of these compounds as photocatalysts has led to an explosive interest in the literature. Recent reviews have concerned themselves generally or partially with the chemistry of iron (342, 552, 688, 814) and ruthenium (800, 803-806, 814) complexes of 2,2 -bipyridine, so these complexes are not discussed further here. In particular, the reader is referred to excellent recent reviews of the photochemical applications of these compounds (41, 43, 44, 176, 194, 443, 624, 625, 877, 954). 

Ruthenium metal appears to have only mild effects, such as irritation of the skin, on the human body. Most compounds of ruthenium that have been studied, however, appear to be far more dangerous to human health. For example, ruthenium tetroxide (RUO4) is not only highly explosive, but also very irritating to the skin, eyes, and respiratory tract (mouth, throat, and lungs). 

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