Chlorides and cyanides

Alkaline cyanides are not often measured cither, but can be present in amounts of a few milligrams per liter. Any alkaline cyanide presence in stripping gases after acidification must be taken into account (HCN is harmful). 

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Without other alternatives, the carboxyalkyl radicals couple to form dibasic acids HOOC(CH)2 COOH. In addition, the carboxyalkyl radical can be used for other desired radical reactions, eg, hydrogen abstraction, vinyl monomer polymerization, addition of carbon monoxide, etc. The reactions of this radical with chloride and cyanide ions are used to produce amino acids and lactams employed in the manufacture of polyamides, eg, nylon. 

Wilkinson s catalyst has also been reported to decarbonylate aromatic acyl halides at 180°C (ArCOX ArX). This reaction has been carried out with acyl iodides, bromides, and chlorides. Aliphatic acyl halides that lack an a hydrogen also give this reaction, but if an a hydrogen is present, elimination takes place instead (17-16). Aromatic acyl cyanides give aryl cyanides (ArCOCN—> ArCN). Aromatic acyl chlorides and cyanides can also be decarbonylated with palladium catalysts. °... 

C20-0093. As ligands, chloride and cyanide are at opposite ends of the spectrochemical series. Nevertheless, experiments show that [CrClg] and [Cr(CN)g] have about the same amount of magnetism. Explain how this can be so. 

Ruveda, M.A. and deLicastro, S.A., Synthesis of dimethyl a-hydroxy phosphonates from dimethyl phosphite and phenacyl chloride and cyanide, Tetrahedron, 28, 6018, 1972. 

The hydration number (the number of water molecules intimately associated with the salt) of the quaternary ammonium salt is very dependent upon the anion. The change in the order of reactivity is thus believed to be due to the hydration of the anion the highly hydrated chloride and cyanide ions are less reactive than expected, and the poorly hydrated iodide fares better under phase transfer conditions than in homogeneous reactions. Methanol may specifically solvate the anions via hydrogen bonding, and this effect is responsible for the low reactivity of more polar nucleophiles in that solvent. 

Table 14 The chlorine 35C1/37C1 leaving group, the incoming nucleophile nC/14C, the secondary a-deuterium, and the 12C/14C a-carbon KIEs for the SN2 reactions between p-substituted benzyl chlorides and cyanide ion in 20% aqueous DMSO at 30°C. ...

Problem 7.30 Write equations for and explain the use of tetrabutyl ammonium chloride, BUjN Cl, to facilitate the reaction between 1-heptyl chloride and cyanide ion. 

Argentometric titration involves the titrimetric determination of an analyte using silver nitrate solution as titrant. Its application in environmental analysis is limited to the determination of chloride and cyanide in aqueous samples. The principle of the method is described below. 

Calculations on ethyl halide reactions include that on the SN2 reaction between ethyl chloride and cyanide ion in DMSO.112 The calculated free energy of activation at the CCSD(T)/6-31+G(2df,2p) level on the B3LYP/6-31G(d)-optimized structure was within 1.5 kcalmol-1 of the experimental value. 

While thermochemical mimicry has been shown for ionic chlorides and cyanides, the same study showed that near-constancy vanished as the corresponding chlorides and cyanides became more covalent57. Perhaps we should not be disappointed that the cyano/chloro difference of the enthalpies of formation of RC1 and RCN, S20 (g Cl, CN R) (equation 20),... 

The yield, however, is poor. A better method is to heat ammonium chloriridate with a slight excess of potassium cyanide for ten to fifteen minutes. Extraction of the melt with boiling water and subsequent evaporation yields crystals of the potassium iridicyanide, the other constituents, namely, potassium chloride and cyanide, being more soluble and remaining in solution. 

Chloride and cyanide in the presence of each other Both silver chloride and silver cyanide are insoluble in water, but soluble in dilute ammonia solution. Three methods are available for the detection of cyanide in the presence of chloride. 

Addition of anionic nucleophiles to alkenes and to heteronuclear double bond systems (C=0, C=S) also lies within the scope of this Section. Chloride and cyanide ions are effieient initiators of the polymerization and copolymerization of acrylonitrile in dipolar non-HBD solvents, as reported by Parker [6], Even some 1,3-dipolar cycloaddition reactions leading to heterocyclic compounds are often better carried out in dipolar non-HBD solvents in order to increase rates and yields [311], The rate of alkaline hydrolysis of ethyl and 4-nitrophenyl acetate in dimethyl sulfoxide/water mixtures increases with increasing dimethyl sulfoxide concentration due to the increased activity of the hydroxide ion. This is presumably caused by its reduced solvation in the dipolar non-HBD solvent [312, 313]. Dimethyl sulfoxide greatly accelerates the formation of oximes from carbonyl compounds and hydroxylamine, as shown for substituted 9-oxofluorenes [314]. Nucleophilic attack on carbon disulfide by cyanide ion is possible only in A,A-dimethylformamide [315]. The fluoride ion, dissolved as tetraalkylammo-nium fluoride in dipolar difluoromethane, even reacts with carbon dioxide to yield the fluorocarbonate ion, F-C02 [840]. 

Conjugate hydrocyanation of oc -unsaturated carboxylic esters, acid chlorides, and acyl cyanides, is effected by reaction with diethylaluminium cyanide [e.g. (128) — (129)]. The acid chloride and cyanide are the most reactive. A double conjugate addition of nitromethane with a 2-methylene-4-en-3-one (130) gave a... 

Gilligan, P. J., Krenitsky, P. J. Divergent mechanisms for the dealkoxycarbonylation of a 2-(3-azetidinyl)malonate by chloride and cyanide. Tetrahedron Lett. 1994, 35, 3441-3444. 

Fig. 3-67. Separation of anions derived from weak inorganic acids using a strongly basic eluent. — Separator column Wescan 269-029 eluent 0.004 mol/L NaOH + 0.0005 mol/ L sodium benzoate flow rate 1.5 mL/min detection indirect conductivity injection volume 100 pL solute concentrations 5 ppm borate (as B), 10 ppm silicate (as Si02), 10 ppm formate and sulfide, 20 ppm chloride and cyanide (system peak appears after 28 min.) (taken from [70]).

Reactions of 3,7-Dimethyloctadienes and their Derivatives.—Geraniol and nerol were sequentially converted into their chlorides and cyanides with no allylic rearrangement on treatment with (Bun)3P-CCl4-KCN in the presence of crown ether.175 2,4,6-Trichloro-4-bromocyclohexa-2,5-dienone selectively brominated geraniol derivatives (functionalized at C-l) under mild conditions to give the... 

Reaction of iV,N-diphenylcarbamoyl chloride and cyanide ion with phthalazine and 1,6-naphthyridine gave the compounds 112 and 113, respectively. 

Table 24 The KIEs found for the Sn2 reaction between ethyl chloride and cyanide in DMSO at 30°C...

A number of 2 -acetamido-2 -deoxy-j -D-glucopyranosides of saturated and A -unsaturated C-19 steroids have been prepared by reaction of the steroid 3- or 17-alcohol with the appropriate chloro-sugar, using a mixed mercuric chloride and cyanide catalyst. The A -acetyl-a-glucosaminides of the saturated steroids could be prepared by anomerisation of the -anomer with titanium tetrachloride. The 2 -amino-2 -deoxy-j8-D-glucopyranosides of digitoxigenin, strophanthidin, and pregnenolone have also been prepared. ... 

The final type of aqueous ionic equilibrium we consider involves a different kind of ion than we ve examined up to now. A simple ion, such as Na" " or S04 , consists of one or a few bound atoms, with an excess or deficit of electrons. A complex ion consists of a central metal ion covalently bonded to two or more anions or molecules, called ligands. Hydroxide, chloride, and cyanide ions are some ionic ligands water, carbon monoxide, and ammonia are some molecular ligands. In the complex ion Cr(NH3)6, for example, Cr is the central metal ion and six NH3 molecules are the ligands, giving an overall 3-1- charge (Figure 19.13). 

H. Muller, Chloride and cyanide determination by use of the flow injection method using ion-selective flow-type electrodes, 3rd Symposium on ion-selective electrodes, Matrafiired, 279 (1980). 

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