HCFC-142b

HCFC-123 HCFC-1416 HCFC-141b HCFC-142b... 

Certain CFCs are used as raw materials to manufacture key fluorinated olefins to support polymer apphcations. Thermolysis of HCFC-22 affords tetrafluoroethylene and hexafluoropropylene [116-15 ] under separate processing conditions. Dechlorination of CFC-113 forms chlorotrifluoroethylene [79-38-9]. Vinyhdene fluoride [75-38-7] is produced by the thermal cracking of HCFC-142b. 

CFC-114 blowing agents and refrigerants HCFC-124 HCFC-142b blends / azeotropes HFCs... 

CFC-11 HCFC-123 HCFC-22 HCFC-141b HCFC-142b CFC-113 HCFC-225ca a HCFC-225cb a... 

Preparation. Thermal elimination of HCl from l-chloro-l,l-difluoroethane (HCFC-142b) [75-68-3] is the principal industrial route to VDF covered by numerous patents (8—19). Dehydrohalogenation of l-bromo-l,l-difluoroethane (20), or 1,1,1-trifluoroethane (HFC-143a) (21—25), or dehalogenation of l,2-dichloro-l,l-difluoroethane (26—28) are investigated alternative routes (see Fluorine compounds, organic-fluorinated aliphatic compounds). 

The commercially preferred monomer precursor HCFC-142b has been prepared by hydrofluorination of acetylene (29), vinyHdene chloride (30—32), or 1,1,1-trichloroethane (33—39). 

Rigid polyurethane for other appliances. Alternatives include HCFC-141b, HCFC-22, blends of -22 and HCFC-142b, pentane, and carbon dioxide/water blowing. In the long term, the alternatives include HFCs. 

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). 

Contains HCFC-22/ HCFC-124. HCFC-142b. as a blowing agent in... 

CFC-114 caFj-caFj HCFC-142b CH3-CCIF2 HFC-143a CH3-CF3... 

Figure 3.6 Sound velocity in polystyrene/HCFC 142b before phase separation as a function of temperature. The blowing agent concentrations (wt%) are indicated. After Sahnoune el al. [189]. Reproduced by permission of the Society of Plastic...

Grim (Oram et al., 1995) and at Mace Head. In the latter case, HCFC-141b increased at a rate of 2.49 + 0.03 pptyr-1, compared to a midpoint concentration of 7.38 ppt, and HCFC-142b increased at a rate of 1.24 + 0.02 ppt yr-1, with a midpoint concentration over the October 1994 to March 1997 time period of 8.78 ppt (Simmonds et al., 1998b). HCFC-141b and -142b have also been detected in the stratosphere (e.g., see Lee et al., 1995). 

Lee, J. M., W. T. Sturges, S. A. Penkett, D. E. Oram, U. Schmidt, A. Engel, and R. Bauer, Observed Stratospheric Profiles and Stratospheric Lifetimes of HCFC-141b and HCFC-142b, Geophys. Res. Lett, 22, 1369-1372 (1995). 

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