A-fluorinated products

Very recently it has been shown that anodically fluorinated product selectivity is greatly affected by fluoride ionic liquids, as shown in Scheme 8.14 [27]. The electrolysis of a phenylthioglycoside derivative 7 in Et3N 4HE provides fluorodesulfurization product 8 exclusively, while that in Et3N 3HE affords a-fluorinated product 9... 

Fluorination of Ketone Enolates. (+)-lV-Fluoro-2,10-(3,3-dichlorocamphorsultam) (1) reacts with ketone enolates to give a-fluoro ketones. For example, reaction of the sodium enolate of propiophenone 2 gives a-fluoropropiophenone 3 in 41% isolated yield (eq 1). No enantioselectivity, however, is observed due to racemization of the product under the reaction conditions. When a tertiary substituted ketone such as a-methyltetralone (4) is employed, the desired a-fluorinated product (S)-(-)-S is obtained in 76% ee and 53% isolated yield (eq 2). In this reaction, (+)-l was found to be more reactive, affording higher yields and better enan-tioselectivities than its parent (-)-N-fluoro-2,10-camphorsultam i.e., 35% ee, < 5% yield. ... 

Anodic monofluorination of the side chain of various heterocyclic compounds has been systematically studied [82-84]. The active methylenethio group attached to heterocycles is selectively fluorinated to give the corresponding a-fluorinated products in moderate to good yields [Eqs. (36) and (37)] [82-87]. In these reactions, the choice of solvent and supporting fluoride salt is of great importance in order to achieve efficient fluorination reaction [84-87]. 

Stereoselective a-fluorination of a-nitro esters 107 was performed using Selectfluor as a fluorinating agent and cinchona alkaloid catalyst 109 by Togni and coworkers (Scheme 6.32) [60]. Under the basic condition (NaH inTHFat —40 °C) were obtained the a-fluorinated products 99 in high yield (up to 91%) with relatively low enantios-electivities (up to 31%). 

Kim and coworkers reported the asymmehic fluorinahon of P-keto phospho-nates in ionic liquids using palladium complex 46 as a catalyst [74]. The fluorinahon of P-keto phosphonate with NFSI in the presence of 5mol% of 46 in [bmim][BF4] at room temperature produced a fluorinated product in 95% yield with 93% ee. The chemical yield and enantioselechvity were quite similar to those obtained in MeOH (8h, 93%, 97% ee). Moreover, the catalyst immobilized in the ionic liquid layer was recycled seven times without any obvious loss in yield or... 

Anodic monofluorination of a-phenylthio-P-lactams 60 in EtjN-SHF/MeCN also leads to production of the corresponding a-fluorinated products in good yields and with high current efficiencies as shown in Eq. 111... 

Moreover, BAM3G being a fluorinated product will not be environmentally friendly, as when mass produced these membranes will pose a problem for their safe disposal. Apart from that, a great deal of information relating to their ionic conductivity, thickness, exact chemical composition, and mechanical strength, hydraulic permeation is proprietary and is not available in the literature. 

Raw Material. The principal raw material for fluorine production is high purity anhydrous hydrofluoric acid. Each kilogram of fluorine generated requires ca 1.1 kg HE. Only a small portion of the hydrofluoric acid produced ia the United States is consumed ia fluorine production. The commercial grade is acceptable for use as received, provided water content is less than 0.02%. Typical specifications for hydrofluoric acid are... 

Fig. 4. Equipment flow sheet of elemental fluorine production and liquefaction plant, 9 t/d capacity. Step 1 purging residual F2 at rates indicated all but a trace of residual F2 is removed in 15min N2 purge is maintained for 1 h to remove last traces. Step 2 HF removal at rates indicated all but a trace of HF is...

Fluorine reacts with ammonia in the presence of ammonium acid fluoride to give nitrogen trifluoride, NF. This compound can be used as a fluorine source in the high power hydrogen fluoride—deuterium fluoride (HF/DF) chemical lasers and in the production of microelectronic siUcon-based components. 

HF is used as a source of fluorine for production of all the various fluorocarbon products. HF reacts in the presence of a suitable catalyst and under the appropriate temperature and pressure conditions with various organic chemicals to yield a family of products. A by-product stream of hydrochloric acid may be co-produced. 

Halogen exchange with KF is not successful ia acetic acid (10). Hydrogen bonding of the acid hydrogen with the fluoride ion was postulated to cause acetate substitution for the haUde however, the products of dissolved KF ia acetic acid are potassium acetate and potassium bifluoride (11). Thus KF acts as a base rather than as a fluorinating agent ia acetic acid. 

Polymer Electrolyte Fuel Cell. The electrolyte in a PEFC is an ion-exchange (qv) membrane, a fluorinated sulfonic acid polymer, which is a proton conductor (see Membrane technology). The only Hquid present in this fuel cell is the product water thus corrosion problems are minimal. Water management in the membrane is critical for efficient performance. The fuel cell must operate under conditions where the by-product water does not evaporate faster than it is produced because the membrane must be hydrated to maintain acceptable proton conductivity. Because of the limitation on the operating temperature, usually less than 120°C, H2-rich gas having Htde or no (

A fluorinated analogue, CFCI2SCI, is made in Europe from trichloromethanesulfenyl chloride and is used for production of the fungicides dichlorofluanid [1085-98-9] (3) and tolylfluanid [731-27-1] (4) (69) ... 

Fluorides. Tantalum pentafluoride [7783-71-3] TaF, (mp = 96.8° C, bp = 229.5° C) is used in petrochemistry as an isomerization and alkalation catalyst. In addition, the fluoride can be utilized as a fluorination catalyst for the production of fluorinated hydrocarbons. The pentafluoride is produced by the direct fluorination of tantalum metal or by reacting anhydrous hydrogen fluoride with the corresponding pentoxide or oxychloride in the presence of a suitable dehydrating agent (71). The ability of TaF to act as a fluoride ion acceptor in anhydrous HF has been used in the preparation of salts of the AsH, H S, and PH ions (72). The oxyfluorides TaOF [20263-47-2] and Ta02F [13597-27-8] do not find any industrial appHcation. 

Titanium Tetrafluoride. Titanium tetrafluoride [7783-63-3] is a white hygroscopic soHd, density 2798 kg/m, that sublimes at 284°C. The properties suggest that it is a fluorine-bridged polymer in which the titanium is six-coordinate. The preferred method of preparation is by direct fluorination of titanium sponge at 200°C in a flow system. At this temperature, the product is sufficiently volatile that it does not protect the unreacted sponge and the reaction proceeds to completion. The reaction of titanium tetrachloride with cooled, anhydrous, Hquid hydrogen fluoride may be used if pure hydrogen fluoride is available. 

Industrially, chlorine is obtained as a by-product in the electrolytic conversion of salt to sodium hydroxide. Hazardous reactions have occuned between chlorine and a variety of chemicals including acetylene, alcohols, aluminium, ammonia, benzene, carbon disulphide, diethyl ether, diethyl zinc, fluorine, hydrocarbons, hydrogen, ferric chloride, metal hydrides, non-metals such as boron and phosphorus, rubber, and steel. 

In the course of synthetic efforts aimed at obtaining 6j5-fluoro steroids, Kirk and Petrow treated a 3)5-acetoxy-6-raethyl-5a,6a-epoxide with boron trifluoride etherate and unexpectedly obtained a fluorine-free acetoxy ketone." Later transformations established that the product was the A-homo-B-norsteroid (104). 

Stenc effects are presumably also responsible for the surprising formation of a chlorinated product from reaction of a hindered fluorinated olefin with potassium fluoride and iodine chloride [U6] (equation 18). 

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