Cyanides, preparation properties

The physical properties of cyanoacetic acid [372-09-8] and two of its ester derivatives are Hsted ia Table 11 (82). The parent acid is a strong organic acid with a dissociation constant at 25°C of 3.36 x 10. It is prepared by the reaction of chloroacetic acid with sodium cyanide. It is hygroscopic and highly soluble ia alcohols and diethyl ether but iasoluble ia both aromatic and aUphatic hydrocarbons. It undergoes typical nitrile and acid reactions but the presence of the nitrile and the carboxyUc acid on the same carbon cause the hydrogens on C-2 to be readily replaced. The resulting malonic acid derivative decarboxylates to a substituted acrylonitrile ... 

Thousands of compounds of the actinide elements have been prepared, and the properties of some of the important binary compounds are summarized in Table 8 (13,17,18,22). The binary compounds with carbon, boron, nitrogen, siUcon, and sulfur are not included these are of interest, however, because of their stabiUty at high temperatures. A large number of ternary compounds, including numerous oxyhaUdes, and more compHcated compounds have been synthesized and characterized. These include many intermediate (nonstoichiometric) oxides, and besides the nitrates, sulfates, peroxides, and carbonates, compounds such as phosphates, arsenates, cyanides, cyanates, thiocyanates, selenocyanates, sulfites, selenates, selenites, teUurates, tellurites, selenides, and teUurides. 

D-Glucosone (XII), prepared from D-glucose phenylosazone (XI) by the action of concentrated hydrochloric acid, is treated in aqueous solution with potassium cyanide. The imino-D-glucoascorbic acid (XIV) which readily separates shows many of the properties of ascorbic acid. Thus it shows a strong selective absorption band in the ultra-... 

The Langmuir-Blodgett method has been used to prepare hybrid films of an anionic Ru(ll) cyanide polypyridyl complex with LDHs [170]. An LDH film was formed on mica owing to the interaction between LDHs particles and the Ru(ll) cyanide polypyridyl complex that was pre-dispersed on the surface of mica. Water-in-oU emulsions composed of octane, water and sodium dodecyl sulfate (SDS) have been used to synthesize Mg/Al LDHs with carbonate as the interlayer anion [171] by constant pH or variable pH methods. A floccule or fiber-like LDH material that possesses similar chemical composition and properties to that synthesized using a conventional variable pH method was obtained. The resulting LDH shows high surface area and a narrow distribution of mesopores. 

Oxynitrilases are enzymes that catalyze the formation and cleavage of cyanohydrins through the stereoselective addition of hydrogen cyanide to aldehydes or methyl ketones giving enantiopure a-hydroxynitriles. The use of (R)-oxynitrilases for the preparation of chiral cyanohydrins has dramatically grown in the last decade because of their possibihties as precursors for the synthesis of many compounds with physiological properties [50]. 

The nitrile group is very sensitive to alkalis and the elimination of it by the action of potassium hydroxide on acetaldehyde cyanohydrin was described by Simpson and Gauthier as one of the reactions of the acetaldehyde cyanohydrin, a substance that they prepared for the first time. That the nitriles of the aldonic acids yield cyanides under the action of alkali, is described by Wohl as one of the properties of penta-acetyl-D-glucononitrile. 

Double cyanides of trivalent vanadium have been prepared which show the properties of co-ordinated compounds, e.g. Ks[V(CN)g] compare with K3[Cr(CN)6] and K3[Fe(CN)6]. 

Cyanide complexes of platinum occur most commonly in the divalent state, although there has been increasing interest in the complexes formed with platinum in a higher oxidation state. Among the complexes most recently studied have been the mixed valent complexes where platinum cyanides in the divalent state are partially oxidized. These complexes form one-dimensional stacks with Pt-Pt interactions. In the solid state these materials show interesting electrical conductivity properties, and these compounds are discussed by Underhill in Chapter 60. In this section the preparative procedures and spectroscopy of the complexes will be covered, but for solid state properties the reader is referred to Chapter 60. 

---