75-45-6 Chlorodifluoromethane

Chlorodifluoromethane is also used as a refrigerant and industrial solvent. 

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A plane of symmetry bisects a molecule so that one half of the molecule is the mirror image of the other half The achiral molecule chlorodifluoromethane for exam pie has the plane of symmetry shown m Figure 7 3... 

Difluoroethanol is prepared by the mercuric oxide cataly2ed hydrolysis of 2-bromo-l,l-difluoroethane with carboxyHc acid esters and alkaH metal hydroxides ia water (27). Its chemical reactions are similar to those of most alcohols. It can be oxidi2ed to difluoroacetic acid [381-73-7] (28) it forms alkoxides with alkaH and alkaline-earth metals (29) with alkoxides of other alcohols it forms mixed ethers such as 2,2-difluoroethyl methyl ether [461-57-4], bp 47°C, or 2,2-difluoroethyl ethyl ether [82907-09-3], bp 66°C (29). 2,2-Difluoroethyl difluoromethyl ether [32778-16-8], made from the alcohol and chlorodifluoromethane ia aqueous base, has been iavestigated as an inhalation anesthetic (30,31) as have several ethers made by addition of the alcohol to various fluoroalkenes (32,33). Methacrylate esters of the alcohol are useful as a sheathing material for polymers ia optical appHcations (34). The alcohol has also been reported to be useful as a working fluid ia heat pumps (35). The alcohol is available ia research quantities for ca 6/g (1992). 

Pyrolysis of chlorodifluoromethane is a noncatalytic gas-phase reaction carried out in a flow reactor at atmospheric or sub atmospheric pressure yields can be as high as 95% at 590—900°C. The economics of monomer production is highly dependent on the yields of this process. A significant amount of hydrogen chloride waste product is generated during the formation of the carbon—fluorine bonds. 

A large number of by-products are formed in this process, mostly in trace amounts more significant quantities are obtained of hexafluoropropylene, perfluorocyclobutane, l-chloro-l,l,2,2-tetrafluoroethane, and 2-chloro-l,l,l,2,3,3-hexafluoropropane. Small amounts of highly toxic perfluoroisobutylene, CF2=C(CF2)2, are formed by the pyrolysis of chlorodifluoromethane. 

About 90% of the chloroform produced goes into the production of HCFC-22 (chlorodifluoromethane [75-45-6]). Of this 90% about 70% is used as a refrigerant and about 30% is used as a starting material in the production of fluoropolymers, such as polytetrafluoroethylene (PTFE). Of the remaining 10% of the chloroform production about 8% is exported and 2% is used in other ways. 

Chlorodifluoromethane Steel, cast iron, brass. Silver, brass, aluminium, steel. 

Chlorobenzene (monochlorobenzene) Chlorobromomethane 2-Chloro-l, 3-butadiene, see Chloroprene Chlorodifluoromethane (Freon 22)... 

Cyclohexane, cumene, para-dichlorobenzene (p-DCBj, chlorodifluoromethane (CFC22J Xylenes... 

Chlorobenzene Producers Association (CPA), 270 p-Chlorobenzotrichloride, 39 Chlorobenzotrifluorides, 39 Chlorobromomethane, 39 Chlorodifluorobromomethane, 39 Chlorodifluoroethane, 39 Chlorodifluoromethane, 39 Chlorodiphenyl, 39 Chloroethanol, 39 2-Chloroethyl vinyl ether, 39 Chlorofluorocarbons, 39 Chloroform, 40 Chloromethyl anilines, 40 Chloromethyl ether, 40 Chloromethyl methyl ether, 40 2-(4-Chloro-2-methylphenoxy) propionic acid, 40 Chloromethyl phenyl isocyanate, 40... 

Sodium difluoromethanesulfonate is prepared from chlorodifluoromethane and sodium sulfite The yield of this carbene reaction is more reproducible in the presence of sodium hydroxide [50] (equation 45)... 

Copyrolysis of 1,1-diehloroperfluoroindane and chlorodifluoromethane or tetrafluoroethylene gives 1-perfluoromethyleneindane as the major product and three minor products [3] (equation 2) Insertion of difluorocatbene into the benzylic carbon-chlorine bond and subsequent loss of a chlonne molecule is observed in the copyrolysis of chlorodifluoromethane and pentafluorobenzotnchlonde to give a-chloroperfluorostyrene as the major product. Aromatic carbon-chlorine bonds are unreactive to the difluorocarbene in this reaction [4] (equation 3). 

Chlorofluorocarbon-blown foam blocks are used to insulate the walls and roofs of some buildings, thus reducing heat losses and helping to conserve fossil fuels. In this area, polyurethane foam competes with polystyrene foam, which until recently was blown with dichlorodifluoromethane (CFC 12) but is now blown with a mixture of chlorodifluoromethane (HCFC 22) and 1 -chloro-l,l-difluoroethane (HCFC 142b). 

In addition to the pyrolysis of chlorodifluoromethane [9], another commercially important synthesis of TFE is based on tnfluoromethane [/O] (equation 1). 

In a later version of the synthesis [9], the trifluoroethyl difluoromethyl ether IS made directly from tnlluoroethanol and chlorodifluoromethane (equation 2) and then chlorinated to give the final product. Again, the major problem is overchlorination, because all the hydrogens are readily replaced by chlorine. Separation of the overchlonnated by-products poses a special problem because of close boiling points. This problem can be solved by adding acetone to create a more easily separable azeotrope of acetone and isoflurane [10]. 

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