672-65-1Relevant articles and documents
Room temperature living cationic polymerization of styrene with HX-styrenic monomer adduct/FeCl3 systems in the presence of tetrabutylammonium halide and tetraalkylphosphonium bromide salts
Banerjee, Sanjib,Paira, Tapas K.,Kotal, Atanu,Mandal, Tarun K.
, p. 1258 - 1269 (2010)
Living cationic polymerization of styrene was achieved with a series of initiating systems consisting of a HX-styrenic monomer adduct (X?=?Br, Cl) and ferric chloride (FeCl3) in conjunction with added salts such as tetrabutylammonium halides (nBu4N+Y-; Y-?=?Br-, Cl-, I-) or tetraalkylphosphonium bromides [nR′4PBr; R′?=?CH3CH2-, CH3(CH2)2CH2-, CH3(CH2)6CH2-] or tetraphenylphosphonium bromide [(C6H5)4PBr] in dichloromethane (CH2Cl2) and in toluene. Comparison of the molecular weight distributions (MWDs) of the polystyrenes prepared at different temperatures (e.g., -25?°C, 0?°C and 25?°C) showed that the polymerization is better controlled at ambient temperature (25?°C). The polymerization was almost instantaneous (completed within 1?min) and quantitative (yield ~100%) in CH2Cl2. In CH2Cl2, polystyrenes with moderately narrow (Mw/Mn?~?1.33-1.40) and broad (Mw/Mn?~?1.5-2.4) MWDs were obtained respectively with and without nBu4N+Y-. However, in toluene, the MWDs of the polystyrenes obtained respectively with and without nBu4N+Y-/nR′4P+Br- were moderately narrow (Mw/Mn?=?1.33-1.5) and extremely narrow (Mw/Mn?=?1.05-1.17). Livingness of this polymerization in CH2Cl2 was confirmed via monomer-addition experiment as well as from the study of molecular weights of obtained polystyrenes prepared simply by varying monomer to initiator ratio. A possible mechanistic pathway for this polymerization was suggested based on the results of the 1H NMR spectroscopic analysis of the model reactions as well as the end group analysis of the obtained polymer.
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Diaz,Blanco
, p. 1313 (1974)
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The Chloroiodination of Deactivated Olefins with Antimony (V) Chloride-Iodine and Iodine Monochloride
Uemura, Sakae,Fukuzawa, Shin-ichi,Okano, Masaya,Sawada, Seiji
, p. 1390 - 1392 (1980)
By the reactions of olefins with an equimolar mixture of SbCl5 and I2 in carbon tetrachloride, various chloroiodoalkanes are obtained in fair to good yields.This method is applicable to various deactivated olefins, the reactions of which to not proceed by the reported method using a mixture of CuCl2 and I2.Iodine monocloride can also be used for this reaction, but in this case both the yield and the regiospecificity of the products are sometimes inferior.
N-Heterocyclic Iod(az)olium Salts – Potent Halogen-Bond Donors in Organocatalysis
Boelke, Andreas,Kuczmera, Thomas J.,Lork, Enno,Nachtsheim, Boris J.
supporting information, p. 13128 - 13134 (2021/08/09)
This article describes the application of N-heterocyclic iod(az)olium salts (NHISs) as highly reactive organocatalysts. A variety of mono- and dicationic NHISs are described and utilized as potent XB-donors in halogen-bond catalysis. They were benchmarked in seven diverse test reactions in which the activation of carbon- and metal-chloride bonds as well as carbonyl and nitro groups was achieved. N-methylated dicationic NHISs rendered the highest reactivity in all investigated catalytic applications with reactivities even higher than all previously described monodentate XB-donors based on iodine(I) and (III) and the strong Lewis acid BF3.
Thiourea-Mediated Halogenation of Alcohols
Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
, p. 12901 - 12911 (2020/11/26)
The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.