From Suitable Chlorine-Containing Compounds

After carbon has been removed from the catalyst, the chlorine content usually falls to 0.6-0.8 wt%. The loss of chlorine must, therefore, be compensated by passing dry air that contains a suitable chlorine compound such as carbon tetrachloride over the catalyst at 450°C. Sufficient chlorine must be used to restore the original 0.9-1.3 wt% chlorine level. About 70% of the total chlorine in the airstream is retained by the catalyst. A high space velocity of up to 5000 h" can be used. 

Polymerization of triphenylmethyl methacrylate in the presence of a chiral anion catalyst results in a polymer with a helical structure that can be coated onto macroporous silica [742,804). Enantioselectivity in this case results from insertion and fitting of the analyte into the helical cavity. Aromatic compounds and molecules with a rigid nonplanar structure are often well resolved on this phase. The triphenylmethyl methacrylate polymers are normally used with eluents containing methanol or mixtures of hexane and 2-propanol. The polymers are soluble in aromatic hydrocarbons, chlorinated hydrocarbons and tetrahydrofuran which, therefore, are not suitable eluents. 

Many compounds containing one or more N—X bonds show unstable or explosive properties (and are also oxidants), and this topic has been reviewed [1]. Difluoroamino compounds, ranging from difluoramine and tettafluorohydrazine to polydifluoroamino compounds, are notably explosive and suitable precautions have been detailed [2,3], Preparative scale A-chlorination of ly and 2y amines by passing them over N-chlorosuccinimide is described. In presence of alumina, ly amines give the N,N -dichloro derivatives. The products must be handled with... 

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