Reactions with fluorine

Thus, for a successful fluorination process involving elemental fluorine, the number of coUisions must be drasticaUy reduced in the initial stages the rate of fluorination must be slow enough to aUow relaxation processes to occur and a heat sink must be provided to remove the reaction heat. Most direct fluorination reactions with organic compounds are performed at or near room temperature unless reaction rates are so fast that excessive fragmentation, charring, or decomposition occurs and a much lower temperature is desirable. 

Chlorine Trifluoride, ClF3, mw 92.46 nearly colorless orpalegrn gas fr p —83°, bp +11.3°. Extremely reactive, comparable to fluorine reactions with org compds and with w take place with expl violence. Can be prepd in 99% purity by reaction of chlorine and fluorine at 280° and condensation of the product at —80°. Used as oxidizer in pioplnts, in incendiaries and for cutting oil well tubes Refs 1) Gmelin-Kraut,-not found 2) Lange (1961), 240 3) CondChemDict (1961),... 

Perchloryl fluoride generally reacts with electron-rich alkencs or with various carbanionie substrates (Scheme 1), where salts are usually prepared in situ and further react at low temperature or in some cases at room temperature temperature control must be taken into account. However. it has been pointed out several times that serious explosions may occur and for this reason the reactions are potentially hazardous and safety precautions must be taken when working with this reagent. Over the last twenty years fluorination reactions with perchloryl fluoride have been partially discussed in several monographs6 8 and review papers.9 12... 

The reactivity of aromatic molecules in fluorination reactions with trifluoromethyl hypofluorite has been studied in detail, and in the case of aniline derivatives the effect of the substituent on nitrogen on the relative reactivity and ortho/para ratio in various aprotic nonpolar, aprotic polar and protic solvents has been determined.5... 

The course of elemental fluorination reactions with various organic acid salts depends on the reaction conditions. The gas-solid fluorination reaction of sodium trifluoroacetate gives up to four products, whose distribution depends on the temperature of the column containing the sodium salt 1 no trifluoroacctyl hypofluoritc is formed. 

Bromo-l-chloro-l,l-difluoroethane (3) is prepared from l,2-dibromo-l,l-dichloroethane (1) in good yield when the fluorination reaction with antimony(III) fluoride/antimony(V) chloride is conducted in two steps. 

Applications of potassium fluoride in all the forms described above will be handled in this section generally. Both protic and aprotic polar solvents are employed for the fluorination reaction with potassium fluoride. Appropriate remarks and references are given in the following discussion section for all the types of potassium fluoride used. 

A coolant channel is guided through the metal block in a serpentine fashion so that reactant and coolant flows are orthogonal [272]. A thermocouple measures the temperature at the product outlet. This microreactor was developed for the (very fast) fluorination reactions with elemental fluorine. Therefore, the surface of the microchannel was inactivated by exposure to the increasing concentration of fluorine in nitrogen. 

In general, secondary and tertiary alcohols do not give satisfying results in fluorination reactions with sulfur tetrafluoride when elimination reactions are possible they become an important side reaction, e.g, with secondary substrates such as l,1.1.4,4,4-hexafluorobutan-2-ol (2). ... 

There are two fluorination reactions with ester substrates reported in the literature which consist of only a single example each. One is the formation of fluoroethene from acetoxyethene and lithium fluoride in the presence of palladium acetate. The other is formation of fluoro-ethane from ethyl orthoformate with silicon tetrafluoride. - ... 

Scheme 2.76 Fluorination reactions with xenon difluoride (A = catalytic amount of SiF4 as a Lewis acid) [169-171].

The combustion of CCI2F2 in oxygen at 500 °C was studied in the presence of more than 20 different catalysts. The combustion products are CO, CO2, and F2. Because of fluorine s tremendous reactivity, metallic and silicon-based catalysts degraded rapidly. The most durable catalyst was found to be BPO4 however, it also did not have a satisfactory life because of fluorine reaction with boron [103],... 

Meshri DT, Hage DB (1999) Fluorine reactions with structured carbon. In Houben-Weyl (ed) methods in organic chemistry, vol ElO. organo-fluorine compounds, 4th edn. Thieme Medical... 

A convenient two-step access to valuable ethyl a-fluorocyclopropanecarboxylates that involves a Michael-initiated ring closure reaction between ethyl dichloroacetate and various terminal electron-deficient alkenes has been developed. In the second reaction step, fluorination reaction with potassium bifluoride takes place through a 1,2-elimination/addition pathway. 

Rozen, S., "Electrophilic Fluorination Reactions with Fluorine and Some Reagents Directly Derived From It," In Synthetic Fluorine Chemistry Olah, G. A. Chambers, R. D. Prakash, G. K. S., Eds. Wiley New York, 1992 p 143. 

In the first step, chloroform is converted into chlorodifluoromethane by catalytic vapor phase fluorination reaction with anhydrous hydrogen fluoride and in the second step, chlorodifluoromethane is subjected to a noncatalytic gas phase pyrolysis at temperature 590-900°C and at atmospheric or subat-mospheric pressures to obtain tetrafluoroethylene in about 95% yield. 

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