Samuel Guthrie, a U.S. physician from Sackets Harbor, New York, also appears to have produced chloroform in 1831 by reacting chlorinated lime with ethanol, as well as noting its anaesthetic properties; he also believed that he had prepared chloric ether, however. Justus von Liebig carried out the alkaline cleavage of chloral. Eugène Soubeiran obtained the compound by the action of chlorine bleach on both ethanol and acetone. In 1834, French chemist Jean-Baptiste Dumas determined chloroforms empirical formula and named it. In 1835, Dumas prepared the substance by the alkaline cleavage of trichloroacetic acid. Regnault prepared chloroform by chlorination of chloromethane. In 1842, Robert Mortimer Glover in London discovered the anaesthetic qualities of chloroform on laboratory animals. In 1847, Scottish obstetrician James Y. Simpson was the first to demonstrate the anaesthetic properties of chloroform on humans, provided by local pharmacist William Flockhart of Duncan, Flockhart and company, and helped to popularise the drug for use in medicine. By the 1850s, chloroform was being produced on a commercial basis, in Britain about 750,000 doses a week by 1895, by using the Liebig procedure, which retained its importance until the 1960s. Today, chloroform – along with dichloromethane – is prepared exclusively and on a massive scale by the chlorination of methane and chloromethane. Production
In industry production, chloroform is produced by heating a mixture of chlorine and either chloromethane (CH3Cl) or methane (CH4).
Uses
In terms of scale, the most important reaction of chloroform is with hydrogen fluoride to give monochlorodifluoromethane (CFC-22), a precursor in the production of polytetrafluoroethylene (Teflon):
CHCl3 + 2 HF → CHClF2 + 2 HClThe reaction is conducted in the presence of a catalytic amount of mixed antimony halides. Chlorodifluoromethane is then converted into tetrafluoroethylene, the main precursor to Teflon. Before the Montreal Protocol, chlorodifluoromethane (designated as R-22) was also a popular refrigerant. Solvent
The hydrogen attached to carbon in chloroform participates in hydrogen bonding. Worldwide, chloroform is also used in pesticide formulations, as a solvent for fats, oils, rubber, alkaloids, waxes, gutta-percha, and resins, as a cleansing agent, grain fumigant, in fire extinguishers, and in the rubber industry. CDCl3 is a common solvent used in NMR spectroscopy. Lewis acid
In solvents such as CCl4 and alkanes, chloroform hydrogen bonds to a variety of Lewis bases. HCCl3 is classified as a hard acid and the ECW model lists its acid parameters as EA = 1.56 and CA = 0.44. Reagent
As a reagent, chloroform serves as a source of the dichlorocarbene :CCl2 group. It reacts with aqueous sodium hydroxide usually in the presence of a phase transfer catalyst to produce dichlorocarbene, :CCl2. This reagent effects ortho-formylation of activated aromatic rings such as phenols, producing aryl aldehydes in a reaction known as the Reimer–Tiemann reaction. Alternatively, the carbene can be trapped by an alkene to form a cyclopropane derivative. In the Kharasch addition, chloroform forms the CHCl2 free radical in addition to alkenes.