Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Patent
1997-08-11
1998-10-13
Owens, Amelia
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
C07C 1908
Patent
active
058213929
DESCRIPTION:
BRIEF SUMMARY
INDUSTRIAL FIELDS WHERE THE INVENTION CAN BE UTILIZED
This invention relates to a manufacturing method for a useful compound of 1,1,1,3,3-pentafluoropropane which can be subustituted for CFC and HCFC which are utilized for a cooling medium, a blowing agent or a cleaning agent.
PRIOR ART
As a manufacturing method for 1,1,1,3,3-pentafluoropropane, it is known that 2,3-dichloro-1 1,1,1,3,3-pentafluoropropane and 2,2,3-trichloro-1,1,1,3,3-pentafluoropropane as raw materials are reduced with hydrogen under the presence of a palladium catalyst carried by active carbon etc.(Japanese Patent Opening No. 256235/94).
However, this known reducing process has a weak point that the activity of palladium catalyst comes to be declined by sintering etc. because the reaction is conducted at a high temperature ranging 250.degree. to 300.degree. C.
OBJECTIVES OF THE INVENTION
The object of this invention is to provide a manufacturing method for obtaining useful 1,1,1,3,3-pentafluoropropane with high yield, maintaining an activity of the catalyst to make its' lifetime longer.
THE CONSTRUCTION OF THE INVENTION
In a manufacturing process of 1,1,1,3,3-pentafluoropropane by reducing 2,3-dichloro-1,1,1,3,3-pentafluoropropane with hydrogen, as a result of closely studying a catalyst which scarcely declines the catalytic activity, the inventors found a process where the decline of catalytic avtivity by sintering etc. can be suppressed by alloying palladium and at least one kind of additional metal selected from the group of silver, gold, copper, zinc, bismuth, rhenium, cobalt, nickel, iridium, ruthenium, rhodium, tantalum, niobium, molybdenum, osmium and tungsten. This invention has thus been accomplished.
That is, the summary of this invention is in a manufacturing method for 1,1,1,3,3-pentafluoropropane in which when 2,3-dichloro-1,1,1,3,3-pentafluoropropane as a raw material is reacted with hydrogen under the presence of a catalyst in a gaseous phase to produce 1,1,1,3,3-pentafluoropropane, a hydrogenation catalyst composed of palladium and at least one kind of additional metal selected from the group of silver, gold, copper, zinc, bismuth, rhenium, cobalt, nickel, iridium, ruthenium, rhodium, tantalum, niobium, molybdenum, osmium and tungsten is used as the catalyst.
As for the process of the gas phase reaction based on the present invention, such processes as the fixed-bed vapor phase reaction and fluidized-bed vapor phase reaction etc. can be used.
The hydrogenation catalyst used in the present invention is composed of palladium and specific additional metal, and they can be an alloy or an oxide thereof. The specific additional metal is at least one kind of metal selected from the group of silver, gold, copper, zinc, bismuth, rhenium, cobalt, nickel, iridium, ruthenium, rhodium, tantalum, niobium, molybdenum, osmium and tungsten.
A ratio of the specific additional metal to palladium can be applied ranging from 0.01 to 100% by weight, and preferably from 0.1 to 30% by weight.
As a preparing method for the hydrogenation catalyst in the present invention, various kind of known preparing method for the hydrogenation catalyst can be applied, for example, an aqueous solution of a salt containing of a catalytic component or the aqueous solution added by hydrochloric acid is impregnated in a carrier before dried and reduced with hydrogen etc.
As a carrier of the hydrogenation catalyst used in the present invention, at least one kind of the carrier selected from active carbon, alumina, silica gel, titanium oxide and zirconia can be used. Particularly, active carbon is preferable because 1,1,1,3,3-pentafluoropropane as the objective can be obtained with high selectivity.
Though the particle size of the carrier has little effect on the reaction, it is preferably from 0.1 to 100 mm.
As for the catalyst concentration on the carrier, though a wide range from 0.05 to 30% by weight can be used, the concentration from 0.5 to 5% by weight is usually recommended.
The reaction temperature in the present invention is usually ranging from
REFERENCES:
patent: 5426253 (1995-06-01), Morikawa et al.
Aoyama Hirokazu
Shibata Noriaki
Yamamoto Akinori
Daikin Industries Ltd.
Owens Amelia
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