Ferric chloride initiation

Besides the electrochemical method, other methods such as the chemically initiated polymerization method, the vapor-phase methods, and the Langmuir-Blodgett method have been devised for the preparation of conducting polymers. In the chemical method, a chemical oxidant such as ferric chloride initiates the polymerization. Polymerization usually results in a powdery product and the resultant powder is then compressed into a pellet or dissolved in a suitable solvent such as methylene chloride or chloroform and spin coated on a substrate. In the vapor-phase technique, which is a variation of the chemical method, a monomer film is vacuum sublimed onto a glass substrate and then exposed to a solution or vapor of ferric chloride for oxidative polymerization. Films thus prepared are usually thick, of the order of micrometers. For some applications in which ultrathin and very uniform films are required, the Langmuir-Blodgelt technique for depositing monolayers has also been tried successfully [5]. 

The polymerization of /-propylene oxide with ferric chloride initiation and with different terminal units (Cl, OH or unsaturated groups) has been deepened later by Corey [96] under these conditions, a 30—40% fraction of optically inactive isotactic polymer was obtained which, in fact, consists of a d- and /-polymer mixture, as is shown by its partial resolution by asymmetric adsorption [97]. 

Addition. Chlorine adds to vinyl chloride to form 1,1,2-trichloroethane [79-00-5] (44—46). Chlorination can proceed by either an ionic or a radical path. In the Hquid phase and in the dark, 1,1,2-trichloroethane forms by an ionic path when a transition-metal catalyst such as ferric chloride [7705-08-0], FeCl, is used. The same product forms in radical reactions up to 250°C. Photochernically initiated chlorination also produces... 

The mixture was refluxed gently on a steam bath for VA hours. Fifteen minutes after initiating the reaction, the reaction mixture gave a negative ferric chloride test. Most of the ethanol and acetic acid were removed by distillation in vacuo, 300 ml of water and 300 ml of ether were added to the concentrate, and the mixture was shaken. The layers were separated, the aqueous layer extracted with fresh ether, and the combined ether extracts were washed with water, dried over anhydrous sodium sulfate, filtered and evaporated to dryness in vacuo. The residue was crystalli2ed by trituration with ether, and the crystals were collected by filtration, washed with hexane and dried. The mother liquors were concentrated to dryness and dissolved in a minimum amount of acetone, whereupon a second crop was obtained. The two crops were combined, dissolved in ethyl acetate, decolori2ed with activated charcoal, and recovered by concentration. 

With gallium chloride, ferric chloride and antimony pentachloride the rate coefficients were dependent upon the concentration of chlorobenzene and the square of the concentration of the catalyst, but the third-order coefficients varied with the initial concentration of the catalyst (Table 103)394. The overall kinetic equation was, therefore,... 

Thus, for the initial chlorination of the ore, ferric chloride can very well be used instead of elemental chlorine. From ferric chloride vapor chlorine can be regenerated by the reaction... 

One surprising example is how ferric (not ferrous) chloride catalyzes the formation of ketyl radicals in a Gringnard-type reaction between ( 113)3001, Mg, and (0Hj)20=O (Ashby and Wiese-mann 1978). The initially formed tert-butyl magnesium chloride reacts with ferric chloride and gives tert-butyl iron(Ill) dichloride ... 

Orotic acid readily forms dimers even when irradiated in liquid medium [582, 583]. 5-Bromouracil (5-BrU) in DNA is dehalogenated, rather than forming cyclobutane-type dimers. Such DNA derivatives are more sensitive to ultraviolet irradiation than normal DNAs [584-594], Irradiation of 5-bromo-uracil and derivatives in aqueous medium produces 5,5 -diuracil [590, 591]. However, derivatives such as 3-sbutyl-5-bromo-6-methyluracil have been reported to yield cyclobutane dimers either by irradiation of frozen aqueous solutions, or by catalysis with free radical initiators, such as aluminium chloride, ferric chloride, peroxides or azonitriles [595]. 5-Hydroxymethyluracil is reported to dimerize very slowly in frozen water at 2537 A [596]. The fundamental research in the photochemistry of the nucleic acids, the monomeric bases, and their analogues has stimulated new experiments in certain micro-organisms and approaches in such diverse fields as template coding and genetic recombination [597-616]. 

Asghar and Khan [33] modified the method by adding K2S2O8 (potassium persulfate) in an acetate buffer at pH 5.6 as the initiator of DMPD". They abandoned ferric chloride, due to the presence of metal ions in the analysed material which could - as a result of the Fenton Reaction... 

The reactions when ferric chloride or ferric acetylacetonate is present occur in three stages (1) an initial fast reaction decreasing in rate, (2) an arrest during which the oxidation rate may be very low, and (3) a "sigmoid phase in which an autocatalytic reaction is finally overtaken by reactant consumption. With the ferric (bissalen) chloride complex, the reaction was accelerated but Stages 1 and 2 did not appear (curve 340R, Figure 2). 

In the presence of gallium chloride, aluminum bromide, aluminum chloride, and ferric chloride, benzoyl azide is decomposed according to eq 2. Here complex formation is very fast, and the decomposition of the complex is the ratedetermining step. The halides do not complex with the phenyl isocyanate formed and, as a consequence, they are not consumed in the reaction. As long as benzoyl azide is in excess, the concentration of the complex is equal to the halide concentration and remains constant. The experimentally determined pseudo-zero-order rate constant depends therefore upon the first power of the initial halide concentration. When, however, the reaction is at a stage where the azide is no longer in excess, the rate of the reaction becomes first order with respect to benzoyl azide and zero order with respect to halide. PhCONj + AlBr, -r - PhCONrAlBr, r+-... 

The chlorination of adamantane by either antimony pentachloride or ferric chloride in carbon tetrachloride gives low (approximately 4) initial tertiary secondary product ratios. Attention was called to the similarity of these ratios to those of known radical processes 36°). 

The most studied telogen is certainly CCl3Br initiated either by UV, peroxide or by redox systems. However, we have demonstrated that in this last case, the redox catalyst, especially ferric chloride, induces a disproportionation which leads to a mixture of new telogens as follows [230] ... 

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