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WO1996017683A1 - Catalyseur d'hydrogenation et procede associe - Google Patents

Catalyseur d'hydrogenation et procede associe Download PDF

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Publication number
WO1996017683A1
WO1996017683A1 PCT/GB1995/002837 GB9502837W WO9617683A1 WO 1996017683 A1 WO1996017683 A1 WO 1996017683A1 GB 9502837 W GB9502837 W GB 9502837W WO 9617683 A1 WO9617683 A1 WO 9617683A1
Authority
WO
WIPO (PCT)
Prior art keywords
catalyst
hydrogenation
carbon
platinum
palladium
Prior art date
Application number
PCT/GB1995/002837
Other languages
English (en)
Inventor
John David Scott
Gary Goodyear
John Charles Mccarthy
Original Assignee
Imperial Chemical Industries Plc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GBGB9424904.2A external-priority patent/GB9424904D0/en
Priority claimed from GBGB9425058.6A external-priority patent/GB9425058D0/en
Application filed by Imperial Chemical Industries Plc filed Critical Imperial Chemical Industries Plc
Priority to JP8517405A priority Critical patent/JPH10510206A/ja
Priority to EP95938548A priority patent/EP0796146A1/fr
Publication of WO1996017683A1 publication Critical patent/WO1996017683A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/23—Preparation of halogenated hydrocarbons by dehalogenation

Definitions

  • This invention relates to a catalyst, in particular a hydrogenolysis (the replacement of halogen by hydrogen in saturated molecules) and/or hydrogenation (addition of hydrogen across ethylenic double-bonds) catalyst, (hereafter referred to collectively as "hydrogenation”) and to hydrogenation processes employing the catalyst, in particular the hydrogenation of halofluorocarbons and hydrohalofluorocarbons to produce hydrofluoroalkanes, for example the hydrogenation of dichlorodifluoromethane and chlorodifluoromethane to produce difluoromethane, the hydrogenation of chloropentafluoroethane to produce pentafluoroethane and the hydrogenation of dichlorotetrafluoroethane and chlorotetrafluoroethane to produce tetrafluoroethane and especially 1, 1 , 1 ,2-tetrafluoroethane.
  • a catalyst in particular a hydrogenolysis (the replacement of halogen by
  • chlorofluorocarbons which are used on a large scale around the world, may be damaging the earth's protective ozone layer and there is now in place international agreement to ensure that their manufacture and use is restricted and eventually completely phased out.
  • Chlorofluorocarbons are used, for example, as refrigerants, as foam blowing agents, as cleaning solvents and as propellants for aerosol sprays in which the variety of applications is virtually unlimited. Consequently, much effort is being devoted to finding suitable replacements for chlorofluorocarbons which will perform satisfactorily in the many applications in which chlorofluorocarbons are used but which will not have the aforementioned damaging effect on the ozone layer.
  • Hydrofluorocarbons which do not contain chlorine but which contain hydrogen.
  • Hydrofluorocarbons such as difluoromethane, also known as HFA 32, pentafluoroethane, also known as HFA 125 and 1, 1, 1 ,2-tetrafluoroethane, also known as HFA 134a, are of interest as replacements, in particular as replacements in refrigeration, air-conditioning and other applications.
  • the present invention is based on the discovery that the activity and particularly the selectivity of palladium catalysts is improved by incorporating a controlled amount of platinum in the catalysts.
  • a hydrogenation catalyst which comprises palladium and platinum in a ratio by weight of 2: 1 to 500: 1 carried on a support.
  • the palladium and platinum components may be used alone or in combination with other metals, for example other Group VIII metals such as nickel, Group I B metals such as Ag and Au or even other metals.
  • the metals are carried on a suitable support, for example alumina, fluorinated alumina, silica, silicon carbide or carbon but in particular alumina or carbon.
  • a suitable support for example alumina, fluorinated alumina, silica, silicon carbide or carbon but in particular alumina or carbon.
  • a carbon carrier where the carbon has a high surface area, eg greater than 200 m 2 /g.
  • Activated carbon supports with low inorganic impurity levels are particularly suitable.
  • the loading of the metal on the support material may be dependent at least to some extent on the particular metal catalyst/support combination being used and the difficulty of the hydrogenation reaction.
  • the % w/w of combined palladium and platinum to support is typically from about 0.1% w/w to about 40% w/w, and preferably from about 0.5% w/w to about 20% w/w, more preferably from about 2.0% w/w to about 20% w/w and especially from about 5% w/w to about 15% w/w.
  • the proportions of palladium and platinum present may vary within a wide range, although we prefer a catalyst in which there is at least twice as much palladium as platinum. We particularly prefer to employ palladium and platinum in the ratio by weight from about 2: 1 to about 500: 1 , and more preferably from about 3 : 1 to about 100: 1.
  • a preferred catalyst comprises from about 0.5% to 20%, in particular from about 5 to 15% w/w palladium and from about 0.05% to about 5%, in particular from about 0.1% to about 4% by weight platinum, especially when supported on an active carbon. Overall the amount of platinum is usually in the range from about 0.01 % w/w to about 10% w/w of the catalyst.
  • a typical method involves impregnating the support with an aqueous solution of a soluble salt of the metal, for example a halide, and thereafter drying the catalyst.
  • the improved catalyst of the invention is particularly useful in the hydrogenation or hydrogenolysis of a halofluorocarbon or hydrohalofluorocarbon with hydrogen at elevated temperature and according to a second aspect of the invention there is provided a process for the production of a hydrofluorocarbon which comprises contacting a halofluorocarbon or hydrohalofluorocarbon with hydrogen at elevated temperature in the presence of the improved hydrogenation catalyst according to the invention
  • halofluorocarbons and hydrohalofluorocarbons used as starting materials comprise at least one atom of chlorine or bromine and generally will be chlorofluorocarbons or hydrochlorofluorocarbons.
  • the chlorofluorocarbon or hydrochlorofluorocarbon will typically comprise 1 , 2 or 3 carbon atoms although it may comprise more than 3, say up to 6, carbon atoms.
  • the (hydro)halofluorocarbon may be unsaturated or saturated, cyclic or acyclic and straight chain or branched chain, although the (hydro)halofluorocarbon will usually be a straight chain saturated acyclic compound, that is a linear (hydro)halofluoroalkane.
  • Particularly useful hydrogenation reactions in which a hydrogenation catalyst according to the invention may be employed include (a) the hydrogenation of a haloethane, in particular a chloroethane, having 4 fluorine atoms, for example 1 J -dichlorotetrafluoroethane, 1 ,2-dichlorotetrafluoroethane and chlorotetrafluoroethane to chlorotetrafluoroethane and/or tetrafluoroethane, in particular 1, 1 , 1 ,2-tetrafluoroethane and (b) the hydrogenation of a compound of formula CF 2 XY where X and Y are independently Cl, Br or H (but not both H) to difluoromethane.
  • a haloethane in particular a chloroethane, having 4 fluorine atoms
  • 1 J -dichlorotetrafluoroethane 1 ,2-dichlorotetra
  • An important feature of successful hydrogenation catalysts is a high hydrogenolysis activity for carbon - chlorine and/or carbon - bromine bonds but a low hydrogenolysis rate for carbon-fluorine bonds, thus avoiding the loss of product by removal of fluorine atoms.
  • the catalyst of the invention is particularly advantageously employed in the production of difluoromethane where it has a marked effect on improving the selectivity with which difuoromethane is produced by reducing the level of over reaction.
  • a process for the production of difluoromethane which comprises reacting a compound of formula XYCF 2 wherein X and Y are each H, Cl or Br but at least one of X and Y is an atom other than hydrogen, with hydrogen at elevated temperature in the presence of a hydrogenation catalyst according to the invention.
  • the process may be conveniently effected by feeding a stream comprising the compound of formula XYCF 2 and hydrogen, as a combined or as separate streams through a vessel containing the hydrogenation catalyst.
  • the starting compounds of formula XYCF 2 are dichlorodifluoromethane, dibromodifluoromethane, chlorobromodifluoromethane, chlorodifluoromethane and bromodifluoromethane. Mixtures of the above compounds may be employed. Usually the compound of formula XYCF 2 will be a chlorinated difluoromethane and chlorodifluoromethane is the preferred starting compound.
  • the proportion of hydrogen to starting compound of formula XYCF 2 may be varied considerably. Usually at least the stoichiometric amount of hydrogen is employed to replace the chlorine and/or bromine atom(s), and considerably greater than stoichiometric amounts, for example 4 or more moles of hydrogen per mole of starting compound may be employed. Where X and Y are each chlorine or bromine, it is preferred to employ at least two moles of hydrogen (the stoichiometric amount) per mole of starting compound. Where the starting compound of formula XYCF 2 is chlorodifluoromethane it is preferred to employ between 1 and 2 moles of hydrogen per mole of chlorodifluoromethane.
  • Atmospheric or superatmospheric pressures for example up to about 60 barg may be employed.
  • operation of the process of the invention at superatmospheric pressure substantially increases the selectivity of the process towards the production of difluoromethane.
  • the process is preferably operated at a pressure in the range from about 2 bar to about 60 bar and more preferably from about 2 bar to about 30 bar, especially 5 bar to 30 bar.
  • the reaction is suitably carried out in the vapour phase at a temperature which is at least about 150°C and not greater than about 500 C C, usually from about 225°C to about 400°C, and preferably from about 240°C to about 360°C.
  • the most preferred temperature is dependent upon the pressure at which the process is operated; at atmospheric pressure, we prefer to operate the process at a temperature in the range from about 220°C to about 320°C whereas at a pressure of about 7.5 barg, we prefer to employ temperatures in the range from about 260°C to about 380°C.
  • Contact times are usually in the range 1 to 60 seconds, especially 5 to 30 seconds when the reaction is carried out in the vapour phase.
  • any unreacted hydrogen and other starting material, together with any organic by-products, may be recycled.
  • a sample of carbon support (supplied by Norrit) with an approximate surface area area of 800 sq.m/g was crushed and sieved to generate particles in the size range 1.0- 1.2 mm. 50 cm 3 - 60 cm 3 of the crushed carbon was then washed in distilled water and the water drained through a no.4 sinter funnel. The washed carbon was then transferred to a Buchner flask . The target weight of palladium chloride or mixed metal chlorides were then dissolved in the minimum volume of warmed concentrated hydrochloric acid and the solution was added to the carbon particles in the Buchner flask.
  • a further 200 cm 3 of distilled water was then added to the flask and the slurry was evaporated to dryness on a rotary evaporator using an oil bath temperature of 120°C.
  • the catalyst was finished by heating the granules in a vacuum oven at 150°C for approximately 16 hours.
  • the above catalyst preparation was repeated at a larger scale.
  • the same method was employed with 300 cm 3 of carbon support and the particle diameter was increased to 3 mm.
  • Catalyst "A” comprised a 10%w/w Pd metal on carbon catalyst and catalyst “B” comprised a 10% Pd plus 1.8%Pt catalyst on the same Norrit carbon support.
  • the catalysts were each prepared by dissolving the metal halides in the minimum volume of hydrochloric acid and impregnating the 1-1.2mm granules of the carbon with the resultant solution. The slurry was agitated and evaporated to dryness. The catalyst was then degassed under a flow of nitrogen at 120°C for 16 hours to produce the finished catalyst.
  • catalyst "A” 50 cm 3 of catalyst "A" was then charged to a l ⁇ n Inconel reactor and heated to 300°C in a 300 ml/min feed of nitrogen for a 2 hour period prior to testing.
  • the test feed mixture was a 2.J molar feed ratio of hydrogen:CFC 115, which was fed at a flow rate of 180 ml/min to the conditioned catalyst.
  • the catalyst was stabilised under these feed conditions for approximately two hours and then cooled under reaction conditions to approximately 200°C. Conversion of CFC 115 and selectivity to HFC 125 were measured and are shown in Table 4. At measured temperatures of 199°C, 213°C and 236°C, the 1 15 conversion was found to increase from approximately 66% to 84% and finally 97%, see examples Al, A2 and A3.
  • the initial reaction selectivity was found to be 99.77 but fell to 99.59 with increasing feed conversion.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Catalysts (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Abstract

L'invention porte sur un catalyseur d'hydrogénation amélioré contenant du palladium et du platine dans une proportion en poids de 2:1 à 500:1 sur un support tel que du carbone, et sur un procédé de production d'hydrofluorocarbures tels que le difluorométhane consistant à mettre en contact un (hydro)halofluorocarbure tel que le chlorodifluorométhane ou le dichlorodifluorométhane, de préférence en phase vapeur, avec de l'hydrogène à haute température, en présence dudit catalyseur.
PCT/GB1995/002837 1994-12-09 1995-12-06 Catalyseur d'hydrogenation et procede associe WO1996017683A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP8517405A JPH10510206A (ja) 1994-12-09 1995-12-06 水素化触媒及び水素化法
EP95938548A EP0796146A1 (fr) 1994-12-09 1995-12-06 Catalyseur d'hydrogenation et procede associe

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GBGB9424904.2A GB9424904D0 (en) 1994-12-09 1994-12-09 Hydrogenation Catalyst and Process
GBGB9425058.6A GB9425058D0 (en) 1994-12-13 1994-12-13 Hyrogenation catalyst and process
GB9425058.6 1994-12-13
GB9424904.2 1994-12-13

Publications (1)

Publication Number Publication Date
WO1996017683A1 true WO1996017683A1 (fr) 1996-06-13

Family

ID=26306140

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1995/002837 WO1996017683A1 (fr) 1994-12-09 1995-12-06 Catalyseur d'hydrogenation et procede associe

Country Status (4)

Country Link
EP (1) EP0796146A1 (fr)
JP (1) JPH10510206A (fr)
CA (1) CA2206337A1 (fr)
WO (1) WO1996017683A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024163A1 (fr) * 1997-11-06 1999-05-20 Gesellschaft Zur Beseitigung Von Umweltschäden Mbh Catalyseur a support et procede permettant de produire des hydrofluorocarbures
WO1999024162A1 (fr) * 1997-11-06 1999-05-20 Gesellschaft Zur Beseitigung Von Umweltschäden Mbh Catalyseur et procede d'appauvrissement hydrogenant de cfc et d'halons contenus dans des phases gazeuses
US7026521B1 (en) 2005-03-28 2006-04-11 Honeywell International Inc. Methane and methyl chloride as selective reducing agent in the transformation of hydrochlorofluorocarbons or chlorofluorocarbons to hydrofluorocarbons
CN111116307A (zh) * 2019-12-25 2020-05-08 中船重工（邯郸）派瑞特种气体有限公司 一种高纯三氟甲烷的制备方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4049576A (en) * 1974-10-04 1977-09-20 Ashland Oil, Inc. Platinum-palladium catalyst for selective hydrogenation of aromatics and olefins in hydrocarbon fractions
GB2108953A (en) * 1981-10-29 1983-05-25 Shell Int Research Process for the preparation of a chloropropyl compound
EP0347830A2 (fr) * 1988-06-21 1989-12-27 Asahi Glass Company Ltd. Procédé pour la fabrication d'éthane-1,1,1,2-tétrafluoro
EP0419412A2 (fr) * 1989-09-20 1991-03-27 Ciba-Geigy Ag Procédé pour la préparation de benzotriazoles
JPH0429944A (ja) * 1990-05-25 1992-01-31 Asahi Glass Co Ltd 含水素クロロフルオロカーボン類の製法
EP0519573A1 (fr) * 1991-06-21 1992-12-23 Shell Internationale Researchmaatschappij B.V. Catalyseur d'hydrogénation et procédé

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4049576A (en) * 1974-10-04 1977-09-20 Ashland Oil, Inc. Platinum-palladium catalyst for selective hydrogenation of aromatics and olefins in hydrocarbon fractions
GB2108953A (en) * 1981-10-29 1983-05-25 Shell Int Research Process for the preparation of a chloropropyl compound
EP0347830A2 (fr) * 1988-06-21 1989-12-27 Asahi Glass Company Ltd. Procédé pour la fabrication d'éthane-1,1,1,2-tétrafluoro
EP0419412A2 (fr) * 1989-09-20 1991-03-27 Ciba-Geigy Ag Procédé pour la préparation de benzotriazoles
JPH0429944A (ja) * 1990-05-25 1992-01-31 Asahi Glass Co Ltd 含水素クロロフルオロカーボン類の製法
EP0519573A1 (fr) * 1991-06-21 1992-12-23 Shell Internationale Researchmaatschappij B.V. Catalyseur d'hydrogénation et procédé

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 9212, Derwent World Patents Index; AN 92-091331 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024163A1 (fr) * 1997-11-06 1999-05-20 Gesellschaft Zur Beseitigung Von Umweltschäden Mbh Catalyseur a support et procede permettant de produire des hydrofluorocarbures
WO1999024162A1 (fr) * 1997-11-06 1999-05-20 Gesellschaft Zur Beseitigung Von Umweltschäden Mbh Catalyseur et procede d'appauvrissement hydrogenant de cfc et d'halons contenus dans des phases gazeuses
US7026521B1 (en) 2005-03-28 2006-04-11 Honeywell International Inc. Methane and methyl chloride as selective reducing agent in the transformation of hydrochlorofluorocarbons or chlorofluorocarbons to hydrofluorocarbons
CN111116307A (zh) * 2019-12-25 2020-05-08 中船重工（邯郸）派瑞特种气体有限公司 一种高纯三氟甲烷的制备方法
CN111116307B (zh) * 2019-12-25 2022-08-19 中船(邯郸)派瑞特种气体股份有限公司 一种高纯三氟甲烷的制备方法

Also Published As

Publication number Publication date
CA2206337A1 (fr) 1996-06-13
JPH10510206A (ja) 1998-10-06
EP0796146A1 (fr) 1997-09-24

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