Compositions – Water-softening or purifying or scale-inhibiting agents
Patent
1993-12-09
1996-06-04
Walsh, Donald P.
Compositions
Water-softening or purifying or scale-inhibiting agents
203 39, 203 50, C07C 1738
Patent
active
055230156
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an azeotropic mixture consisting essentially of hydrogen fluoride (hereinafter, referred to as "HF") and dichloromethane (hereinafter, referred to as "R-30"), an azeotropic mixture consisting essentially of HF and chlorofluoromethane (hereinafter, referred to as "R-31") and an azeotropic mixture consisting essentially of HF and difluoromethane (hereinafter, referred to as "R-32"), and a process for the removal of HF from a mixture comprising HF and R-30, R-31 and/or R-32.
R-32 is focused on as a substitute cooling medium of chlorodifluoromethane, and R-30 and R-31 are starting materials for the production of R-32.
2. Description of the Related Art
R-30, R-31 and/or R-32 are conventionally produced by reacting a chlorinated hydrocarbon such as R-30 with HF. Hitherto, a process has been employed in which HF is removed by washing the mixture produced by the reaction and unreacted materials comprising HF, R-30, R-31 and R-32 with an aqueous phase. This process is not so effective because an large amount of an alkali is required to neutralize the washing aqueous solution, and also because a waste from the neutralization has to be treated.
SUMMARY OF THE INVENTION
The present invention provides a process to concentrate or remove HF or other components by forming an azeotropic mixture of HF and R-30, R-31 or R-32 and optionally utilizing liquid separation of a mixture of HF and R-30 and/or a mixture of HF and R-31 into an upper liquid phase and a lower liquid phase under certain conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a process flow sheet of one embodiment in which HF is removed according to the present invention. In FIG. 1, the numeral 11 indicates a starting mixture stream, 12 indicates a stream of R-31, 13 indicates a feed stream, 14 indicates a distillation apparatus, 15 indicates a distillate stream, 16 indicates a reflux stream, and 17 indicates a bottom product stream.
FIG. 2 shows a process flow sheet of another embodiment in which HF is removed according to the present invention. In FIG. 2, the numeral 21 indicates a liquid-liquid separation apparatus, 23 indicates a distillation apparatus, 25 indicates a distillate stream, 27 indicates a reflux stream, 29 indicates a bottom product stream, 31 indicates a cooler, 33 indicates a distillation apparatus, 35 indicates a distillate stream, 37 indicates a reflux stream, 39 indicates a bottom product stream, and 41 indicates a cooler.
DETAILED DESCRIPTION OF THE INVENTION
The present inventors have made intensive studies on the process to remove HF from a mixture comprising HF and R-30, R-31 and/or R-32, so that it has been found that the combinations of HF and R-30, HF and R-31 and HF and R-32 each forms an azeotropic mixture having a minimum boiling point, respectively, and thus the present invention has been made. These mixtures can be used as refluxes in distillation operations in which HF is removed from a mixture comprising HF and R-30, R-31 and/or R-32, whereby effective separation is achieved.
In the first aspect, the present invention provides an azeotropic mixture consisting essentially of HF and R-30, an azeotropic mixture consisting essentially of HF and R-31 and an azeotropic mixture consisting essentially of HF and R-32. These mixtures have boiling points at atmospheric pressure of about 12.degree. C., about -11.degree. C., and about -53.degree. C., respectively.
In the second aspect, the present invention further provides a process for the concentration or the removal of any one of the components of the azeotropic mixtures by using the azeotropic phenomena.
The terms "concentration" and "removal" herein used are intended to mean relative concepts. That is, the concentration of one component in a mixture means the removal of other components in the mixture rather than said one component.
Namely, by distilling a mixture comprising HF and R-30, the azeotropic mixture of HF and R-30 is removed from the original mixture so that R-30 subs
REFERENCES:
patent: 3400077 (1968-09-01), Orfeo et al.
patent: 3490739 (1970-01-01), Buckman et al.
patent: 3728268 (1973-04-01), Burt
patent: 3789004 (1974-01-01), McMillan et al.
patent: 4020112 (1977-04-01), Boswell, Jr. et al.
patent: 4169807 (1979-10-01), Zuber
patent: 4911792 (1990-03-01), Manzer et al.
patent: 4950364 (1990-08-01), Wismer
patent: 4975156 (1990-12-01), Wismer
Komatsu Satoshi
Koyama Satoshi
Matsumoto Takeo
Tanaka Yoshinori
Tsuda Takehide
Daikin Industries Ltd.
Hardee John R.
Walsh Donald P.
LandOfFree
Azeotropes of hydrogen fluoride with dichloromethane, difluorome does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Azeotropes of hydrogen fluoride with dichloromethane, difluorome, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Azeotropes of hydrogen fluoride with dichloromethane, difluorome will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-381250