Читать книгу Concise Handbook of Fluorocarbon Gases - Sina Ebnesajjad - Страница 40

Commercial fluorocarbons are classified as aliphatic compounds which means they have saturated or unsaturated linear chemical structures. Cyclic fluorocarbons are considered part of the aliphatic group but they are not used in any significant quantity in the applications of the rest of the aliphatic fluorocarbons. Consequently, cyclic compounds are not included in this chapter.

Carbon forms its strongest bond with fluorine. The credit for demonstrating the stability of the C–F bond goes to the French chemists Dumas and Peligot, who heated dimethyl sulfate with potassium fluoride and obtained methyl fluoride [see Eq. (3.2)] [15].

(3.2)

The first nucleophilic replacement of another halogen by fluorine was attributed to a genius, the Russian musician and gifted chemist Alexander Borodin [16]. He synthesized benzoyl fluoride by replacement of chlorine in benzoyl chloride using Fremy’s Salt (KF+HF) [17]. The reaction, called halex (abbreviation for halogen exchange) has continued to be the most significant way to produce C–F bonds on a commercial scale [12].

The pioneering work of Belgian chemist Frederic Swarts breathed a new life into the lagging chemistry of aliphatic fluorine compounds. Swartz conducted halogen exchange on polychlorides and polybromides through the use of combined antimony trifluoride and bromine (SbF₃ + Br₂). He elucidated dehalogenation reaction using Zn and dehydrohalogenation using K₂CO₃ could selectively remove halogens other than fluorine leading to the formation of fluorinated olefins. Swarts has been credited with the first synthesis of CCl₂F₂ by Midgley and Henne of the Frigidaire Co. (part of General Motors), who pioneered the use of fluorinated hydrocarbons in the refrigeration industry [18, 19].

In the 1950s and 1960s, study of the fluorocarbons began leading to developments for biological activity. Fluorocarbons, for instance, such as Fluroxene^® (CF₃CH₂OH=CH₂) started a massive change in the types of inhalation anesthetics drugs. In the 1970s fluorocarbons became the agent of choice for inhalation anesthesiology. Other fluorocarbon related developments include artificial blood and respiratory fluids [18].