Carbon tetrachloride (CCl4) is a colorless, non-combustible liquid that can strongly refract light. The substance has a sweetish odor. Carbon tetrachloride also has a narcotic effect. Under normal temperature conditions, the element exhibits a chemical inertness. The substance does not react with either acids (including concentrated sulfuric acid), or with bases. Along with this, the compound quite noticeably interacts with individual metals. In the presence of iron or aluminum, for example, carbon tetrachloride decomposes gradually with water in accordance with the equation: CCl4 + 2H2O = CO2 + 4CH1. In other cases, at ordinary temperature, this transformation does not occur to a noticeable extent.
Carbon tetrachloride. The properties
The specific gravity of the substance is 1.593, the boiling point is 76.6 degrees. The substance hardens at a temperature of minus 22.87 degrees. At minus 44.66, carbon tetrachloride has a transition point, the use of which is recommended for calibrating thermometers.
In water, the compound dissolves very slightly. At twenty degrees in one hundred grams of water, 0.08 grams of substance is dissolved. The dielectric constant of carbon tetrachloride is quite low (at eighteen degrees - 2.3). In this case, the substance is characterized by high light refractive power. The refractive index for yellow light is n = 1.463.
The properties of carbon tetrachloride include its ability to dissolve organic substances. In all respects, the substance is mixed with alcohol and other organic liquids. In this regard, the compound is widely used in laboratory conditions, for technical needs as a solvent for resins, fats, oils and other substances. In addition, carbon tetrachloride is used to extinguish fires. The substance is also used in medicine as an anthelmintic and anesthetic.
The compound is prepared by chlorination of carbon disulfide in the presence of manganese (II) chloride or another halogen carrier. As a result, sulfur chloride is formed, which, in the presence of optimal catalysts (FeS, for example) and under the influence of moderate heating (up to about sixty degrees) also reacts with carbon disulfide (CS2). It is possible to conduct the process so that the reactions will proceed in parallel. Sulfur precipitated in the process will be returned as a source component to obtain CS2. The purification of carbon tetrachloride is carried out by washing with potassium liquor, immediately after which fractional distillation is carried out.
One of the main challenges facing specialists is the choice of the most effective method for processing carbon tetrachloride. The urgency of the problem is mainly due to the fact that, according to the Montreal Protocol, this substance is prohibited due to its destructive effect on the ozone layer.
When a compound is burned using air as an oxidizing agent, a simultaneous supply of fuel is necessary for binding to hydrogen chloride. Fuel is also needed to supply heat. If there is a small amount of hydrogen chloride, it can be converted to sodium chloride. This is possible by injecting a solution of sodium hydroxide into the combustion gases. In other cases, the release of hydrogen chloride from gases as hydrochloric acid.
Some authors prefer catalytic oxidation. In comparison with the combustion of carbon tetrachloride, the catalytic oxidation process is characterized by a higher degree of destruction of organochlorine waste and is not accompanied by the formation of dioxins.