Fluorosulfonic acid catalyst

Imidazole 24 condenses with triphenylmethanol 25 in presence of chloro- or fluorosulfonic acid catalyst in dichloromethane at RT yielding l-(triphenylmethyl) imidazole (26, 75%) (Equation 8). ... 

THE can be polymerized by many strongly acidic catalysts, but not all of them produce the requked bitimctional polyether glycol with a minimum of by-products. Several large-scale commercial polymerization processes are based on fluorosulfonic acid, HESO, catalysis, which meets all these requkements. The catalyst is added to THE at low temperatures and an exothermic polymerization occurs readily. The polymerization products are poly(tetramethylene ether) chains with sulfate ester groups (8). 

Acids are poor catalysts for ring cleavage of thiirane 1,1-dioxides but are good catalysts for reactions of thiirane 1-oxides with nucleophiles. These reactions of episulfoxides are believed to proceed by protonation of the oxygen atom (but see the NMR evidence cited above for 5-protonation in fluorosulfonic acid) and will be treated in the section on nucleophilic reactions. 

A similar effect is achieved by Af-methylation of the imidazolide with fluorosulfonic acid methyl estertl8] or methyl trifluoromethylsulfonatet ] as catalyst ... 

Fluorosulfonic acid can be used in fluorination reactions, and it functions as a catalyst in reactions such as alkylation and polymerization. One of the most important uses of FS03H and C1S03H is as sulfonating agents to introduce the -S03H group into various organic materials. 

Potassium tetrafluoroborate is used as catalyst with fluorosulfonic acid in the addition of hydrogen fluoride to acetylene (4) in the liquid phase.67... 

Fluorosulfonic acid is a fluorinating agent, and it also functions as an acid catalyst for alkylation, polymerization, and other reactions. Finally, both HSO3F and HSO3CI are... 

It is prepared by passing HF and S03 in fluorosulfonic acid which acts as a solvent as well as heat transfer media. Over 20,000 metric tons of HSO3F are produced per year. It is mostly used as catalyst in the alkylation of branch chain paraffins [26-29], in the polymerization [30-31]. Fluorosulfonic acid is a very strong acid and when added to olefins, it remarkably increases the acidity of the system and enhances its catalytic activity similar to SbF5, TaFs and NbF5 [32-35], It is also used in a chemical process to produce SiF4 [36,37] and BF3 [38],... 

Acid catalysts are required for alkane isomeiizations and all the reactions of this type probably involve carbonium ions. Optically active tertiary alkanes can be racemized by sulfuric acid at room temperature or by fluorosulfonic acids at -80 C. ... 

Chloro-l fluoroethane (10) is prepared by treating chloroethene with anhydrous hydrogen fluoride ° in the vapor phase at 20-70 C in the presence of a catalyst consisting of active charcoal impregnated with 10-45 % by weight fluorosulfonic acid or with hydrogen fluoride/ titanium(IV) chloride. ... 

There are various procedures for the preparation of polyethers. These procedures typically start with oxirane or oxirane derivatives (e.g. propylene oxide, etc.). Base catalyzed anionic polymerization, acid initiation, or complex coordination catalysis can be used for the reaction [1-3], Not only oxiranes can generate polyethers. Diols also can be used for polyether synthesis. Other source compounds include tetrahydrofuran, which can be polymerized to a polyether using fluorosulfonic acid (HSO3F) as a catalyst, oxetane (trimethylene oxide) or oxetane derivatives, which can be polymerized to generate polyethers with practical applications such as poly[bis(chloromethyl)oxetane], etc. 

Silyl donor and catalyst. This compound FSOsSiMes, readily obtained by reaction of allyltrimethylsilane with fluorosulfonic acid at —78°, is comparable and sometimes superior to trimethylsilyl triflate in catalytic activity. 

Ammonia Dibutyltin maleate Dibutyltin oxide Fluorosulfonic acid Phosphine Sodium ethylate Sodium hydride Tetrabutyl titanate Tetraisopropyl titanate p-Toluene sulfonic acid Zirconium butoxide catalyst, condensation reactions Dibutyltin diacetate Piperidine catalyst, conductive polymers Iron (III) toluenesulfonate catalyst, conversion of acetylene to acetaldehyde Mercury sulfate (ic) catalyst, copolymerization Di butyl ether catalyst, cracking Zeolite synthetic... 

Studies by Kiersznicki and co-workers demonstrated that chlorosulfonic acid is an effective catalyst in the alkylation of arenes by reaction with alkenes. Benzene, toluene and ethylbenzene were alkylated by propene, elhene and 2-butene in the presence of chlorosulfonic acid which strongly catalysed the alkylations and inhibited polyalkylation. Increasing the concentration of the catalyst enhanced the proportion of /7-isomers in the products. Fluoro-, chloro-and bromobenzenes were similarly alkylated by reaction with C2-C4 alkenes using chlorosulfonic acid as catalyst. The optimum alkylation conditions were with a halobenzene alkene ratio of 1 0.25, a catalyst concentration of 0.33 mol mol" of fluorobenzene and 0.5 mol mol of the other halobenzenes, a temperature of 70 C and a reaction time of 2 hours. Alkylation with propene gave haloisopropylbenzenes the monoalkyl products were obtained as o-, m- and p- mixtures, the relative amounts depended on the quantity of catalyst used and the by-products were dialkyl derivatives, sulfonic acids and sulfones. In the reaction of benzene with propene, fluorosulfonic acid was a more potent alkylation catalyst than chlorosulfonic acid. ... 

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