Halo-hydrocarbons

The components are ordered by their relative amount, as in Table 3.6. Methane and C02 largely dominate, but other species keep the attention, even in very small amounts. Particularly harmful is H2S, highly toxic for humans. Its level, as well as for benzene and halo-hydrocarbons, should be of a few ppm in the end products. 

Simons process — Electrochemical polyfluorination reactions of organic compounds are the only efficient way to industrial production of perfluorinated compounds. The reaction proceeds in the solution of KF in liquid HF (b.p. 19.5 °C), where the starting substances as alcohols, amines, ethers, esters, aliphatic hydrocarbons and halo-hydrocarbons, aromatic and heterocyclic compounds, sulfo- or carboxylic acids are dissolved. During anodic oxidation, splitting of the C-H bonds and saturation of the C=C bonds occur and fluorine atoms are introduced. 

Fig. 7.20 presents the final flowsheet. Firstly, the landfill gas enters an equilibrium adsorption unit, where the trace impurities HjS, aromatics and halo-hydrocarbons are removed. The next step is the separation of COj by physical or chemical absorption. 

In spite of being ionic many quaternary ammonium salts dissolve m nonpolar media The four alkyl groups attached to nitrogen shield its positive charge and impart lipophilic character to the tetraalkylammonium ion The following two quaternary ammonium salts for example are soluble m solvents of low polarity such as benzene decane and halo genated hydrocarbons... 

Participation of fluorocarbocations, derived from carboxylic acids and from halo acetones, in reactions of carbonyl compounds with sulfur tetrafluoride has been directly evidenced by trapping them with aromatic hydrocarbons [207, 20S],... 

Although the method operated well, a number of intriguing points remained (i) the bad fit of aliphatic hydrocarbon log P with 2/values, (ii) the irregular fit of log P for simple halo-alkanes with calculation data, and (iii) the correction factor of-0.46 for structures with electronegativity facing alkyl bulk and the impossibility of connecting this correction with CM. 

Oxidation of benzene to phenol. This was attempted in the former U.S.S.R. and Japan on a pilot-plant scale. High yields were reported, but full-scale operation apparently was discontinued because of destruction of product by irradiation and the possibility of explosion in the reaction vessel. The latter danger can be controlled in the oxidation of halo-genated hydrocarbons such as trichloro- or tetrachloroethylenes, where a chain reaction leads to the formation of dichloro- or trichloro-acetic acid chlorides through the respective oxides. 

Hutchinson, T.C., Hellebust, J.A., Tam, D., Mackay, D., Mascarenhas, R.A., Shiu, W.Y. (1980) The correlation of the toxicity to algae of hydrocarbons and halogenated hydrocarbons with their physical-chemical properties. In Hydrocarbons and Halo-genated Hydrocarbons in the Aquatic Environment. Afghan, B.K., Mackay, D., Eds., pp. 577-586. Plenum Press, New York. 

Table 5. Rate Constants for 1,2-H Shifts of Halo and Acetoxycarbenes in Hydrocarbon Solvents0...

VII Aromatic hydrocarbons, halo-substituted aromatic hydrocarbons, nitro compounds, aromatic ethers... 

Polycarbonates are attacked by aldehydes, ketones, esters, ethers, aromatic and halo-genated hydrocarbons, organic and mineral concentrated acids, concentrated bases, amines, phenols. 

Figure 11.3 Stereoselective halo-hydroxylation of the monoterpene hydrocarbon (IS)-(+)-3-carene by CPO in the presence of hydrogen peroxide and halide ions (X — CC, Br or C).

---