Fluorine compounds Freon

Stannous fluoride, a compound of tin and fluorine, is much less dangerous. It is added to drinking water and toothpaste to strengthen the enamel in the teeth of the user. Another compound of fluorine is teflon, a plastic made of carbon and fluorine, which is used in kitchenware. The fluorine-containing compound freon is used in air-conditioners and refrigerators, and is harmless. 

As an example, when automotive catalytic mufflers and converters were introduced many years ago, the automobile industry required the petrochemical industry to eliminate lead from gasoline since lead degraded and reduced the effectiveness of the catalyst and caused the destruction of the gasoline. One set of industrial compounds that can harm catalysts are halogens, a family of compounds that include chlorine, bromine, iodine, and fluorine. Bromine, while not prevalent in industry, is present in chemical plants. Freons are fluorine compounds. Silicone is another compound that is deleterious to catalysts. It is used as a slip agent, or a lubricant, in many industrial processes. Phosphorous, heavy metals (zinc, lead), sulfur compounds, and any particulate can result in shortening the life of the catalyst. It is necessary to estimate the volume or the amount of each of those contaminants, to assess the viability of catalytic technologies for the application. 

Fluorine is combined either directly or indirectly with other elements to form compounds such as hydrofluoric acid, fluoropolymers and is used in the synthesis of organic fluorine compounds such as fluorides as in the manufacture of Freon (i.e., dichlo-rodifluoromethane, CCI2F2), which is used as a refrigerant. Fluorine is used in the manufacture of uranium hexafluoride that is necessary for the separation of the isotopes of uranium in centrifuges in the production of nuclear weapons. Fluorine and its compounds are used in producing more than 100... 

A carbon atom can be bonded to as many as four halogen atoms, so an enormous number of organic halides can exist. Completely fluorinated compounds are known as fluorocarbons or sometimes perfluorocarbons. The fluorocarbons are even less reactive than hydrocarbons. Saturated compounds in which all H atoms have been replaced by some combination of Cl and F atoms are called chlorofluorocarbons or sometimes freons. These compounds were widely used as refrigerants and as propellants in aerosol cans. However, the release of chlorofluorocarbons into the atmosphere has been shown to be quite damaging to the earth s ozone layer. Since January 1978, the use of chlorofluorocarbons in aerosol cans in the United States has been banned, and efforts to develop both controls for existing chlorofluorocarbons and suitable replacements continue. The production and sale of freons have been banned in many countries. 

Small atom with a big ego was the title of the ACS Symposium in San Francisco in 2000, where a number of current scientific and industrial aspects of fluorine-related chemistry were discussed. This small atom has been providing mankind with a lot of benefits, in the form of special products such as Teflon , freon, fluoro-liquid crystals, pharmaceutical and agrochemical compounds, and so on, all of which have their own unique properties created by the characteristic nature of fluorine. Nowadays, organic fluorine compounds have attracted a great deal of interest from the scientists involved in many fields of science and technology. 

Fluorine compounds have many uses. One of the most notable of these is the manufacture of chlorofluorocarbon compounds known by the trade name Freon. These are chemical combinations of chlorine, fluorine, and carbon, an sample of which is dichlorodifluoromethane, CI2CF2. These compounds used to be widely employed as refrigerant fluids and blowing agents to make foam plastics they were also once widely used as propellants in aerosol spray cans. Uses of chlorofluorocarbons have now been phased out because of their role in destroying stratospheric ozone (discussed with oxygen, above). 

Dmowski W (2012) 1,2-Dibromotetrafluoroethane (Freon 114B2) as a building block for fluorine compounds. J Fluorine Chem 142 6-13... 

Similar to the application discussed above, the production of heat can be used in a more complex design to generate mechanical energy in the so-called stored chemical energy propulsion systems (SCEPS). SCEPS are typically used for underwater propulsion of torpedoes (see Eigure 14.4b) and use the reaction between molten hthium and any gaseous fluorine compound (see Eigure 14.4a) such as SF [18] or fluorocarbons such as Freon [19]. 

I iL-un 12 (CCljFj) which is now banned by the ozone protection treaty. Also used is Dichloro-difluoromethane, Freon 22 (CHClFj), and chloro-difluoromethane. Several analogous compounds containing carbon, fluorine, chlorine, and sometimes hydrogen are available. 

C05-0071. Freons (CFCs) are compounds that contain carbon, chlorine, and fluorine in various proportions. They are used as foaming agents, propellants, and refrigeration fluids. Freons are controversial because of the damage they do to the ozone layer in the stratosphere. A 2.55-g sample of a particular Freon in a 1.50-L bulb at 25.0 °C has a pressure of 262 torr. What is the molar mass and formula of the compound ... 

New freon agent compounds containing only fluorine atoms are being considered because fluorine atoms do not disturb the ozone layer in the manner as chlorine atoms. Can you explain why ... 

S -Mono-, di-, and trifluoro derivatives of methionine and 5-fluoroalkyl derivatives of cysteine are accessible through fluorination. Thus, fluorination of methionine sulfoxide with xenon fluoride, or more easily using DAST, provided 5-monofluor-omethionine. Photochemical trifluoromethylation of homocysteine leads to 5-trifluoromethionine. These S -fluoroalkyl compounds are also available through fluoroalkylation of homocysteine. Thus, the addition of difluorocarbene (formed from Freon 11 (CHF2CI)) affords S -difluoromethionine. ... 

There are numerous natural contributors of chlorine to the stratosphere, for example, volcanic eruptions. The main concern regarding ozone destruction in recent years is associated with human activities that have increased chlorine and other synthetic chemical input into the stratosphere. At the top of the list of such chemicals are chlo-rofluorocarbons, or CFCs. CFCs are compounds that contain carbon, chlorine, and fluorine they were first developed in 1928. Common CFCs are called Freons, a trade name coined by the DuPont chemical company. CFC compounds are nonreactive, nontoxic, inflammable gases. Because of their... 

Continuing dissatisfaction amongst fluorine chemists with the cumbersome alphanumeric ASHRAE ( Freon ) codes for fluorocarbons (which contain no provision for branched-chain compounds) has led to interesting proposals recently concerning alternative codes for HFCs and HFEs.10 To be fair to ASHRAE. when its predecessor, ASRE, standardized the so-called Du Pont code in the late 1950s, no one could have foreseen the proliferation of lists of volatile fluorocarbons (and hence coded designations) arising from the impressive commercial drive to locate environmentally acceptable in-kind replacements for C.FCs and Halons.8... 

Bromine monofluoride or iodine monofluoride can be prepared from the corresponding elements in trichlorofluoromethane at — 781 and — 45 C,2,3 respectively. The compounds are unstable and decompose at low temperatures, iodine monofluoridc at — 14 C2,3 and bromine monofluoride, in part, even at — 78 C.1 Therefore, they are used, without separation and purification, in Freon solutions at low temperatures or, most frequently, as stoichiometric mixtures bromine trifluoride/bromine and iodine pentafluoride/iodine. A solution of iodine monofluoride, obtained by bubbling nitrogen-diluted fluorine gas into a suspension of iodine in trichlorofluoromethane at — 75 C, was used for addition to alkene C = C bonds. The reaction is regioselective and in most cases obeys the Markovnikov rule.4 Iodine monofiuoride prepared in situ reacts quite efficiently with steroidal alkenes.4... 

In connection with the study of the role Freon compounds play in the depletion of ozone in the atmosphere, a demand has arisen for 13C-labeled fluorinated hydrocarbons in infrared spectroscopic examination. For this purpose,13C-isotopically enriched trichlorofluoromethane, dichlorodifluoromethane, chlorotrifluoromethane, trifluoromethane, chlorodifluoromethane, and dichlorofluoromethane have been prepared from 13CC 4 and 13CHC13.73... 

All three compounds (WF6 and MoF6 are best) will bring about a reaction (not a fluorination) that may have synthetic utility at 0CC in l,l,2-trichloro-l,2,2-trifluoroethane (Freon 113) or chloroform they will cleave N,TV-dimethyl- and N-tosylhydrazones and oximes back to the parent carbonyl compounds12,14 (UF6 converts any first-formed aldehydes into acid fluorides1213). All three hexafluorides will convert1215 tertiary amines into carbonyl compounds and carboxylic acids into acid fluorides.16 They also dope polyacetylene to the metallic regime.17... 

Examples of modem fluorine-containing herbicides, insecticides, and fungicides are shown below Most of these compounds are prepared starting from fluorinated bulk chemicals, such as fluorinated carbocyclic and heterocyclic compounds, benzotnfluonde, fluorinated acetic acid derivatives, and Freons Direct fluonnation is used only occasionally by producers of fine chemicals and will, at least in the near future, remain the domain of producers of bulk chemicals who have the necessary technical expertise... 

Owing to the extreme chemical activity of fluorine, the chief uses of this element arise in connection with the production of its compounds. Thus, sodium fluoride is commonly used as a flux, as an insecticide, and as a wood preservative. Ammonium fluoride is sometimes used as a disinfectant. The compound dichlorodifluoromethane (CC12F2) is used as an insecticide propellent and is an important commercial refrigerant (Freon), particularly well suited for use in domestic refrigeration units. 

Fluoropolymers represent a rather specialized group of polymeric materials. Their chemistry is derived from the compounds used in the refrigeration industry, which has been in existence for more than 60 years. In the 1930s, efforts were made to develop nontoxic, inert, low boiling liquid refrigerants mainly for reasons of safety. The developed refrigerants based on compounds of carbon, fluorine, and chlorine, commonly known as freons, quickly became a commercial success. Eventually, they also became widely used as aerosol propellants. 

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