Methanol, iron chloride species

Figure 5 shows that the absorption spectrum of the tetrachloroferrate ion, with a characteristic maximum at 3150 A., is completely developed in such a solution. The dotted line is the spectrum of an oxidation mixture. The spectrum resembles that of a solution of FeC, but the characteristic maximum at 3600 A. appears to be shifted to 3580 A., and the extinction coefficient at the latter wavelength is lower than that at 3150 A. The result suggests that the principal iron (III) species in the oxidation mixtures is Cl3Fe( OCH3)". Figure 6 shows the effect of metallic chlorides on the spectrum of methanolic solutions of ferric chloride. 

Status of the Composition of the Iron (II) Chloride Species Methanol. Since ferrous chloride behaves as a weak electrolyte in methanol and in our investigation solutions of relatively high concentra-... 

Equation 4 represents stepwise equilibrium between iron (II) chloride and chloride ion, without specifying the amount of methanol bound to each metal ion. Equation 5 shows that the concentration of any chloro-iron(II) species can be represented as a function of the total iron (II) concentration, where A, the proportional constant, is a polynomial function of free chloride and equilibrium constants. 

The relationship between the reaction in nonaqueous solvents and that in water is obscure. Since the kinetics are different, it is likely that the mechanism is also different. In methanol the chloride-catalyzed reaction is second order with respect to iron (II) whereas ligand-catalyzed reactions show only first-order dependence on ferrous ion in aqueous solution. In water, rate-limiting solvolysis of species such as XFe 02, to produce H02, may occur simply because formation of the binuclear compound, required for the rate-limiting step in methanol, is inhibited by strong solvation of iron (II) in aqueous solution. 

Dr, Wu Yes, we have indeed. The matter is treated in the first part of the discussion section of the paper, Status of the composition of the iron (II) chloride species in methanol. Participation by such a species is compatible with our data, but can not be proved rigorously for a number of reasons. 

Interest continues in the conversion of phenols to half esters of c/5,cw-muconic acid (14). Japanese workers have obtained (14) in 44% yield from phenol itself using copper(i) chloride and oxygen in methanol. However, it appears that copper(ii) species are the true catalysts since catechol can be converted to (14) in 80—85% yield in the absence of oxygen using copper(n) salts. The oxidation of phenol to c/. ,c/5 -muconic acid itself has also been effected using peracetic acid with both copper(n) and iron(in) species as catalysts catechol has been identified as an intermediate in the latter case. 

C03-0108. What species are present in solution when the following compounds dissolve in water (a) sodium dichromate (b) copper(II) chloride (c) barium hydroxide (d) methanol (e) sodium hydrogen carbonate and (f) iron(III) nitrate. 

A particularly simple variation of this reaction has been developed (47, 48) in which the catalytic nickel species is formed in situ by reduction of nickel chloride with a manganese -iron alloy in the presence of thiourea. Allyl halide is added and at the same time acetylene and carbon monoxide are bubbled through the methanolic solution. Conversion is almost complete and yields of ar-methyl-2,5-dienoate of up to 80% have been claimed. 

N. A. Stephenson, A. T. Bell, Effects of methanol on the thermodynamics of iron(III) [tetrakis (pentafluorophenyl)]porphyrin chloride dissociation and the creation of catalytically active species for the epoxidation of cyclooctene, Inorg. Chem. 45 (2006) 5591. 

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