Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-06-20
2001-10-02
Rotman, Alan L. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06297389
ABSTRACT:
BACKGROUND OF THE INVENTION
This application is a 371 national stage application of International Patent Application No. PCT/EP99/00003, filed on Jan. 4, 1999, which has priority benefit of Italian Patent Application No. M198A000021, filed on Jan. 9,1998.
1. Field of the Invention
The present invention relates to a process for selective hydrogenation of maleic or succinic anhydride to gamma-butyrolactone (GBL) in the vapor phase using a catalyst comprising a mixed oxide of copper and zinc.
2. Background Art
The present invention relates to a process for selective hydrogenation of maleic or succinic anhydride to gamma-butyrolactone (GBL) in the Sapour phase using a catalyst comprising a mixed oxide of copper and zinc
GBL represents an example of a small volume commodity of great industrial interest, because of its increasing demand.
The main use of GBL is as intermediate for the synthesis of solvents with lower environmental impact than chlorinated ones, like pyrrolidone and N-methylpyrrolidone. It is also the raw material for the production of N-vinilpyrrolidone, of herbicides, pharmaceuticals and rubber additives.
The first works on GBL synthesis appeared in the 1940's, due to the start up of the Reppe process from acetylene and formaldehyde to give 1,4 butanediol (BDO) and then GBL by dehydrogenation. The drawbacks of this process are connected with the fluctuating prices of the raw materials and, mainly, with the hazard and the environmental impact of the use of both acetylene and formaldehyde.
During the second half of this century, other technologies have been studied and the number of patents about GBL production processes alternative to the Reppe process constantly increased.
The availability of maleic anhydride on industrial scale led to the development of new technologies for producing GBL, tetrahydrofurane (THF) or BDO by hydrogenation of maleic anhydride or of maleic anhydride derivatives like maleic acid diesters or succinic anhydride.
The liquid phase hydrogenation of maleic anhydride to GBL has been employed in commercial production, but never reached great industrial importance.
Many patents describe the vapor phase hydrogenation of maleic anhydride or its esters, but mainly for the production of BDO; for instance, WO 86/03189 describe the vapor phase hydrogenation of diethyl maleate to BDO. WO 86/07358 describes a similar process for GBL production.
From a technological and economical point of view the esters of maleic acid or other maleic acid and/or succinic acid derivatives are less desirable raw materials compared with maleic anhydride.
Many patents describe the direct vapor phase hydrogenation of maleic anhydride to GBL, but none of the processes disclosed are completely satisfactory.
Some of these patents claim the use of copper chromites as catalysts (e.g. U.S. Pat. No. 3,065,243) but with unsatisfactory conversion and selectivity. Similar systems were claimed in U.S. Pat. No. 3,580,930 or in EP 332 140 (Cu/Zn/Cr/Al), but none of them are completely satisfactory in terns of GBL yield, productivity, by-products formation and catalyst durability. Moreover chromium containing catalysts should not be the choice because of the negative environment impact of chromium, due to the toxicity of its compounds.
The WO 91/16132 disclose a process for the GBL production from maleic anhydride using a Cu/Zn/Al catalyst calcined at 400-525°C. Such a high temperature is a draw-back in terms of plant design and operation. Different catalytic systems, based on noble metal catalysts such as Cu/Pd and Cu/Pt have been described in e.g. U.S. Pat. No. 4,105,674. The cost of the noble metal is the draw back of these catalysts.
BACKGROUND OF THE INVENTION
The object of the present invention is to provide a new and environmentally friendly process for the production of GBL by vapor phase hydrogenation of maleic anhydride and/or succinic anhydride with essentially quantitative conversion of the starting material, very high selectivity and using a commercial chromium-free catalyst.
The present invention provides a process for the vapor phase hydrogenation of maleic and/or succinic anhydride to GBL over a catalyst comprising a mixed oxide of copper and zinc.
BRIEF DESCRIPTION OF THE INVENTION
The content of Copper as CuO is 50-90 wt % and Zinc as ZnO is 10-50 wt %. Preferably the mixed oxide contains 60-80 wt % CuO and 20-40% wt ZnO. The catalyst composition may further contain inert components, such as tabletting aids or inert fillers.
Preferred catalysts are commercially available e.g. from SOd Chemie, Germany. In the active state, the catalytically active oxide material may include some metallic components (like metallic copper) formed in the activation step or during the hydrogenation.
The mixed oxide catalyst is commonly subjected to an activation treatment comprising gradually increasing its temperature from room temperature to 2000-380° C., preferably from room temperature to 2500-300° C. in the presence of a hydrogen-containing gas.
The hydrogen-containing gas in the activation treatment may be a mixture of hydrogen and nitrogen. After the activation treatment the catalyst is ready for use. Activation requires a time usually varying from about 8 to 48 h, depending on reactor size and design.
The activation of the catalyst is exothermic. In case the reactor does not provide an efficient heat removal the hydrogen-containing gas must be suitably diluted or the space velocity must be increased to control exothermic peaks. Hydrogen dilution results in longer time for the exothermic phase of activation. Large adiabatic reactors usually requires the longest activation times.
During operation molten maleic anhydride or succinic anhydride or a mixture thereof is expediently vaporised in an hot hydrogen stream in a mixing section; the mixture can then be fed into the reactor packed with the above described activated catalyst. Optionally the catalyst can be packed between two layers of an essentially inert support material, possibly with the same size and shape of the catalyst. Suitable examples of essentially inert support materials include silica, alumina, silica-alumina compounds (e.g. mullite), silicon carbide, steatite and titania.
The reaction pressure is preferably between about 1 and 100 bar, more preferably between about 1 and 30 bar.
The molar ratio of hydrogen to the anhydride in the feed is between 10:1 and 300:1 and more preferably between 40:1 and 200:1. Lower hydrogen to anhydride ratios usually result in tar formation and short catalyst life, higher ratios tend to penalise the productivity of the catalyst.
The reaction temperature is preferably between about 150 and 350° C., and more preferably between 200 and 300° C.
As it is well known by those skilled in the art, temperature and pressure range in the hydrogenation reaction depend on the desired product mixture. Increasing temperature will result in the mix containing more THF, while increasing pressure will yield substantial amounts of BDO.
REFERENCES:
patent: 3065243 (1962-11-01), Dunlop et al.
patent: 3580930 (1971-05-01), Miya et al.
patent: 4105674 (1978-08-01), De Thomas et al.
patent: 5112495 (1992-05-01), Bartha et al.
patent: 5347021 (1994-09-01), Taylor et al.
patent: 5698713 (1997-12-01), Lancia et al.
patent: WO 86/03189 (1986-06-01), None
patent: WO 86/07358 (1986-12-01), None
patent: WO 91/16132 (1991-10-01), None
CA Reference 119:225800m, “Method for preparation of gamma-butyrolactone.”, vol. 119, p. 997, 1993.*
CA Reference 119:225800m, “Method for preparation of gamma-butyrolactone.”, Szelejewska et. al., vol. 119, p. 997, 1993.*
Chemical Abstracts, vol. 70, No. 23, (1969), p. 283, abstract No. 77355x.
Chemical Abstract, vol. 119, No. 27, (1993), p. 997, abstract No. 225800m.
Castiglioni Gian L
Fumagalli Carlo
Fisher Christen & Sabol
Lonza S.P.A.
Robinson Binta
Rotman Alan L.
LandOfFree
Process for the production of gamma-butyrolactone does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the production of gamma-butyrolactone, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the production of gamma-butyrolactone will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2617416