socl2

Ответ от Вася Иванов[гуру]
Thionyl chloride is an inorganic compound with the chemical formula SOCl2. It is a moderately volatile colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately 45,000 tons per year being produced during the early 1990s.[5] It is toxic and will react violently with water to produce toxic gases, it is also listed as a Schedule 3 compound as it may be used for the production of chemical weapons.Thionyl chloride is sometimes confused with sulfuryl chloride, SO2Cl2, but the properties of these compounds differ significantly. Sulfuryl chloride is a source of chlorine whereas thionyl chloride is a source of chloride ions.Contents 1 Production 2 Properties and structure 3 Reactions 3.1 With oxygen species 3.2 With nitrogen species 3.3 With sulphur species 3.4 With phosphorus species 3.5 With metals 3.6 Other reactions 4 Batteries 5 Safety 6 See also 7 ReferencesProductionThe major industrial synthesis involves the reaction of sulfur trioxide and sulfur dichloride:[6] SO3 + SCl2 → SOCl2 + SO2Other methods include syntheses from phosphorus pentachloride, chlorine and sulfur dichloride, or phosgene: SO2 + PCl5 → SOCl2 + POCl3 SO2 + Cl2 + SCl2 → 2 SOCl2 SO3 + Cl2 + 2 SCl2 → 3 SOCl2 SO2 + COCl2 → SOCl2 + CO2The first of the above four reactions also affords phosphorus oxychloride (phosphoryl chloride), which resembles thionyl chloride in many of its reactions.Properties and structureCrystal structure of SOCl2SOCl2 adopts a pyramidal molecular geometry with Cs molecular symmetry. This geometry is attributed to the effects of the lone pairs on the sulfur(IV) centre.In the solid state SOCl2 forms monoclinic crystals with the space group P21/c.[7]StabilityThionyl chloride has a long shelf life, however "aged" samples develop a yellow hue, possibly due to the formation of disulfur dichloride. It slowly decomposes to S2Cl2, SO2 and Cl2 at just above the boiling point.[6][8] Thionyl chloride is susceptible to photolysis, which primarily proceeds via a radical mechanism.[9] Samples showing signs of ageing can be purified by distillation under reduced pressure, to give a clear colourless liquid.[10]ReactionsThionyl chloride is mainly used in the industrial production of organochlorine compounds, which are often intermediates in pharmaceuticals and agrichemicals. It usually is preferred over other reagents, such as phosphorus pentachloride, as its by-products (HCl and SO2) are gaseous, which simplifies purification of the product.Many of the products of thionyl chloride are themselves highly reactive and as such it is involved in a wide range of reactions.With oxygen speciesThionyl chloride reacts with water to form sulfur dioxide and hydrochloric acid. This process is highly exothermic. SOCl2 + H2O → 2 HCl + SO2Classically, it converts carboxylic acids to acyl chlorides.[11][12][13] SOCl2 + RCO2H → RC(O)Cl + SO2 + HClBy a similar process it also converts alcohols to alkyl chlorides. If the alcohol is chiral the reaction generally proceeds via an SN1 mechanism with retention of stereochemistry;[14] however, depending on the exact conditions employed, stereo-inversion can also be achieved. Historically the use of SOCl2 in combination with a tertiary amine such as pyridine was called the Darzens halogenation however this name is rarely used by modern chemists.SNi reaction mechanism.gifReactions with an excess of alcohol produce sulfite esters, which can be powerful methylation, alkylation and hydroxyalkylation reagents.[15] SOCl2 + 2 ROH → (RO)2SO + 2 HClFor example, the addition of SOCl2 to amino acids in methanol selectively yield