Chlorination s. a. Halogenation

Chlorides s. a. Halides, Hydrochlorides, Replacement Chlorination s. a. Halogenation, Replacement of hydrogen by halogen... 

Iodine monochloride [7790-99-0] ICl, mol wt 162.38, 78.16% I, is a black crystalline soHd or a reddish brown Hquid. SoHd ICl exists ia two crystalline modifications the a-form, as stable mby-red needles, d = 3.86 g/mL and mp 27.3°C and as metastable brownish red platelets, d = 3.66 g/mL, mp 13.9°C and bp 100°C (dec). Iodine monochloride is used as a halogenation catalyst and as an analytical reagent (Wij s solution) to determine iodine values of fats and oils (see Fats and fatty oils). ICl is prepared by direct reaction of iodine and Hquid chlorine. Aqueous solutions ate obtained by treating a suspension of iodine ia moderately strong hydrochloric acid with chlorine gas or iodic acid (118,119). 

Since bromination and chlorination result in a greater variety of di-substituted products of thieno[2,3-Zi]thiophene 1 than of thieno[3,2-6]-thiophene 2, the conclusion has been drawn that a halogen in position 2 in thienothiophene 1 deactivates position S to a lesser extent than in thienothiophene 2 and that the halogen deactivating effect in 1 is similar to that in thiophene. 

---