Trichloromethane conductivity

The reaction of a carboxylic acid with N,Af -carbonyldiimidazolellH33 (abbreviated as CDI), forming an imidazolide as the first step followed by alcoholysis or phenolysis of the imidazolide (second step), constitutes a synthesis of esters that differs from most other methods by virtue of its particularly mild reaction conditions.t41,[5] It may be conducted in two separate steps with isolation of the carboxylic acid imidazolide, but more frequently the synthesis is carried out as a one-pot reaction without isolation of the intermediate. Equimolar amounts of carboxylic acid, alcohol, and CDI are allowed to react in anhydrous tetrahydrofuran, benzene, trichloromethane, dichloromethane, dimethylformamide, or nitromethane to give the ester in high yield. The solvents should be anhydrous because of the moisture sensitivity of CDI (see Chapter 2). Even such unusual solvent as supercritical carbon dioxide at a pressure of 3000 psi and a temperature of 36-68 °C has been used for esterification with azolides.[6]... 

The procedure can also be conducted using other water immiscible solvents such as ether, trichloromethane, and benzene.2... 

The first step is set up to produce hydrogen fluoride (FtF), and the second yields trichloromethane (chloroform). Chloroform is then partially fluorinated with hydrogen fluoride to chlorodifluoromethane using antimony fluoride (SbFj) as a catalyst in the third step. Finally, in the fourth step, chlorodifluoromethane is subjected to pyrolysis, in which it is converted to tetrafluoroethylene. The pyrolysis is a non-catalytic gas-phase process carried out in a flow reactor at atmospheric or subatmo-spheric pressure and at temperatures 590°C to 900°C (1094°F to 1652°F) with yields as high as 95%. This last step is often conducted at the manufacturing site for PTFE because of the difficulty of handling the monomer [9]. 

The third kinetic study involved the reaction of 120 (Z = H) with arylnitriles and acetonitrile conducted in 1,1,2-trichloromethane at 50.6°C. " Even though 121 is the main product (equation 88), byproducts such as 127, 128 and even traces of diphenylketene were detected. 

Modern carbene chemistry started, however, in a rather unusual way when Hine (1950) conducted a kinetic study of the alkaline hydrolysis of trichloromethane (chloroform). He proposed a two-step a-elimination involving CCI2 as an intermediate. The result of this mechanistic study was unusual because it opened a new field of synthetic organic chemistry, whereas, in general, such studies improve our understanding of fields already known from synthetic work. Mine s dichlorocarbene was subsequently applied to a cyclopropane synthesis by Doering and Hoffmann (1954, see later in this section). 

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