Synthesis of thionyl chloride

Preparation of thionyl chloride

Preparation of thionyl chloride from sulfur dioxide and phosphorus pentachloride

Preparation of thionyl chloride

Preparation of thionyl chloride

To the round bottom flask equipped with a reflux condenser and gas inlet tube, 50 of phosphorus pentachloride are placed. Dry sulfur dioxide is passed over phosphorus pentachloride. At the beginning of the reaction phosphorus pentachloride absorbs sulfur dioxide and becomes liquid, later on reaction flask should be gently heated until all phosphorus pentachloride dissolves. When the reaction is complete the crude thionyl chloride is purified by fraction distillation.  The products are separated by repeated careful fractionation, using an efficient column. The boiling point of thionyl chloride, 77° C and phosphorus oxychloride boils at 108° C. This preparation is generally not completely free of phosphorus compounds. The yield of thionyl chloride is 50% of theoretical.

Thionyl chloride also could be prepared by reacting sulfur dichloride with sulfur trioxide.

Preparation of thionyl chloride by reacting sulfur dichloride with sulfur trioxide

Preparation of thionyl chloride by reacting sulfur dichloride with sulfur trioxide

Handbook of preparative inorganic chemistry, by G. Brauer, Vol. 1, 1963, 382-383


thionyl dichloride



InChI Key


Canonical SMILES


MeSH Synonyms

thionyl chloride

Depositor-Supplied Synonyms

THIONYL CHLORIDE, Sulfinyl chloride, Thionyl dichloride, Sulfurous dichloride, Sulfurous oxychloride, Sulfur oxychloride, Sulfinyl dichloride, Thionylchloride, 7719-09-7, SOCl2, Dichlorosulfoxide, Sulfur chloride oxide, Sulfur chloride oxide (Cl2SO), Thionyl chloride solution, CCRIS 1280, HSDB 859, FYSNRJHAOHDILO-UHFFFAOYSA-N, EINECS 231-748-8, UN1836, AI3-10628, Thionyichloride, thiony-chloride, thionyl-chloride, sulphinyl chloride, thionyl -chloride, thionyl chloride-, dichloridooxidosulfur, sulfur dichloride oxide, Sulfuryl(IV) chloride, Sulfur oxide dichloride, ACMC-1BIJW, AC1L2NEG, AC1Q3VQX, Sulfur monoxide dichloride, Thionyl chloride (socl2), [SCl2O], Sulfur oxychloride (socl2), UNII-4A8YJA13N4, KSC377I0P, 4A8YJA13N4, CHEBI:29290, CTK2H7407, 230464_SIAL, 293121_SIAL, 320536_SIAL, 320544_SIAL, 447285_SIAL, AKOS016016202, RL04949, RTR-024676, UN 1836, AN-21833, Thionyl chloride [UN1836] [Corrosive], Thionyl chloride [UN1836] [Corrosive], LS-152830, TL8005304, TR-024676, FT-0660394, I14-111452

Removed Synonyms

CID24386, T2040, T2048

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