Cyanide, inorganic salts

Benzoin Condensation. The benzoin condensation is a related reaction consisting of treating an aromatic aldehyde with potassium cyanide or sodium cyanide usually in an aqueous ethanolic solution. Breslow studied the effects of inorganic salts on the rate... 

No studies were located regarding quantitative absorption in humans after dermal exposure to cyanide gas or common inorganic salts. Evidence that cyanide can be absorbed through the skin of humans is provided in case reports of toxic effects in humans after accidental dermal contact with cyanide (see Section 2.2.3). 

Exposure to inorganic cyanide, its salts, or cyanohydrins by any route produces similar respiratory effects in animals. 

In the case of thiol and inorganic salts, the best result was obtained for thiophenol and sodium cyanide, and DS of 90% was attained (60°C) with minimum amounts of C=C formation even for p-thiocresol (equivalent) and potassium carbonate. 

In a 5-I. round-bottom flask fitted with a stopper holding a reflux condenser and a separatory funnel, are placed 294 g. (6 moles) of sodium cyanide and 300 cc. of water. The flask is heated on a steam bath until most of the sodium cyanide is in solution. This requires two to three hours. A solution of 500 g. (2.47 moles) of trimethylene bromide (Note 1) in 11. of 95 per cent alcohol is then added through the separatory funnel over a period of forty to sixty minutes. The mixture is refluxed for thirty to forty hours (Note 2) on a steam bath. Then the solvent is removed, preferably under reduced pressure. The residue, consisting of sodium bromide, sodium cyanide, and trimethylene cyanide, is extracted with 300-400 cc. of ethyl acetate, which dissolves the trimethylene cyanide and does not dissolve the inorganic salts. This solution is filtered and the salt washed once with about 100 cc. of ethyl acetate. The ethyl acetate is distilled at ordinary pressure (Note 3) and the residual liquid is distilled under reduced pressure. The yield of trimethylene cyanide boiling at i44-i47°/i3 mm. or i3i-i34°/io mm. is 180-200 g. (77-86 per cent of the theoretical amount). 

Note Highly polar solvent sweet, ethereal odor soluble in water flammable, burns with a luminous flame highly toxic by ingestion, inhalation and skin absorption miscible with water, methanol, methyl acetate, ethyl acetate, acetone, ethers, acetamide solutions, chloroform, carbon tetrachloride, ethylene chloride, and many unsaturated hydrocarbons immiscible with many saturated hydrocarbons (petroleum fractions) dissolves some inorganic salts such as silver nitrate, lithium nitrate, magnesium bromide incompatible with strong oxidants hydrolyzes in the presence of aqueous bases and strong aqueous acids. Synonyms methyl cyanide, acetic acid nitrile, cyanomethane, ethylnitrile. 

This inorganic style of attraction is rare in organic reactions. A more common cause of organic reactions is attraction between a charged reagent (cation or anion) and an organic compound that has a dipole. An example that we shall explore in this chapter is the reaction between sodium cyanide (a salt, NaCN) and a carbonyl compound such as acetone. Sodium cyanide is made up of sodium cations, Na+, and cyanide anions, CN-, in solution. 

Inorganic salts, which contain metal ions, do not dissolve in organic solvents such as benzene. However, by surrounding the metal ion with a chelate called a crown ether the desired solution can be made. The mining industry uses cyanide ions to dissolve gold out of the quartz rocks in which it is often found. The cyanide ligands are removed in subsequent chemical steps. 

CHEMICAL PROPERTIES chemical action will slowly release cyanides toxic vapors generated when heated reacts violently with strong oxidizers dissolves somewhat in inorganic salts will attack some forms of plastics, rubber, and coatings heat contributes to instability FP (5°C, 42°F) LFL/UFL(4.4%, 16.0%) AT (522°C, 973°F) HC (-13.360 Btu/lb, -420 cal/g, -10.7 x lO J/kg) HF (31.4 kJ/mol liquid at 298.15K). 

The term phase transfer catalysis was coined by Starks to describe the mechanism of catalysis of reactions between water-soluble inorganic salts and water-insoluble organic substrates by lipophilic quaternary ammonium and phosphonium ions Ql). His investigations of nucleophilic displacement reactions, such as that of aqueous sodium cyanide with 1-chlorooctane, and the investigations of Makosza on reactions of aqueous sodium hydroxide with chloroform to generate dichlorocarbene, and with active ketones and nitriles to generate carbanions, pioneered the field in the mid-1960 s. It was nearly fifteen years before many such processes were adopted in industry. Starks now estimates there are about sixty phase transfer catalytic processes in use worldwide, mostly in pharmaceutical and fine chemical manufacturing (32V... 

Manufacture of inorganic compounds, e.g. sodium cyanide, sodium salts (11)... 

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