Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1998-11-12
2000-06-20
Owens, Amelia
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
549429, 549325, 568853, C07C 5714
Patent
active
060779640
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the production of butane-1,4-diol, .gamma.-butyrolactone and tetrahydrofuran.
Butane-1,4-diol, together with variable amounts of .gamma.-butyrolactone and tetrahydrofuran, can be produced by hydrogenolysis of maleic anhydride. A major use of butane-1,4-diol is as a feedstock for the plastics industry, particularly for the production of polybutylene terephthalate. It is also used as an intermediate for the production of .gamma.-butyrolactone and of the important solvent, tetrahydrofuran.
Maleic anhydride is normally produced by vapour phase oxidation of a hydrocarbon feedstock, such as benzene, mixed C.sub.4 olefins, or n-butane, in the presence of a partial oxidation catalyst. In the partial oxidation of benzene there is typically used a supported vanadium pentoxide catalyst promoted with MoO.sub.3 and possibly other promoters. The reaction temperature is from about 400.degree. C. to about 455.degree. C. and the reaction pressure is from about 1 bar to about 3 bar, while about 4 times the theoretical amount of air is used in order to stay outside the explosive limits. The contact time is about 0.1 s. When the feedstock is a mixed C.sub.4 olefin feedstock, i.e. a mixed butenes feedstock, then the partial oxidation catalyst may be vanadium pentoxide supported on alumina. Typical reaction conditions include use of a temperature of from about 425.degree. C. to about 485.degree. C. and a pressure of from about 1.70 bar to about 2.05 bar. The volume ratio of air to butenes may be about 75:1 in order to stay below explosive limits. Alternatively it is possible, according to more modern practice, to design the plant so that satisfactory safe operation can be achieved, despite the fact that the feed mixture of air and butenes is within the flammable limits. In the case of n-butane as feedstock, the catalyst is typically vanadium pentoxide and the reaction conditions include use of a temperature of from about 350.degree. C. to about 450.degree. C. and a pressure of from about 1 bar to about 3 bar. The air:n-butane volume ratio may be about 20:1, even though this may be within the flammable limits. One design of reactor for such partial oxidation reactions comprises vertical tubes surrounded by a jacket through which a molten salt is circulated in order to control the reaction temperature.
In each case a hot vaporous reaction mixture is recovered from the exit end of the reactor which comprises maleic anhydride vapour, water vapour, carbon oxides, oxygen, nitrogen, and other inert gases, besides organic impurities such as formic acid, acetic acid, acrylic acid, and unconverted hydrocarbon feedstock.
One way of recovering maleic anhydride from such a reaction mixture is to cool it to about 150.degree. C. using a steam-producing stream and then to cool it further to about 60.degree. C. by cooling it against water in order to condense part of the maleic anhydride, typically about 30% to about 60% of the maleic anhydride present. The remainder of the stream is then scrubbed with water.
Scrubbing with water or with an aqueous solution or slurry is described, for example, in U.S. Pat. No. 2,638,481. Such scrubbing results in production of a solution of maleic acid which is then dehydrated, by distilling with xylene, for example, so as to remove the water and re-form the anhydride. A disadvantage of such a procedure, however, is that an unacceptable proportion of the product remains in the vapour phase. In addition, some of the maleic acid is inevitably isomerised to fumaric acid. The byproduct fumaric acid represents a loss of valuable maleic anhydride and is difficult to recover from the process system since it tends to form crystalline masses which give rise to process problems.
Because of this isomerisation problem a variety of other anhydrous scrubbing liquids have been proposed. For example, dibutyl phthalate has been proposed as scrubbing liquid in GB-A-727828, GB-A-763339, and GB-A-768551. Use of dibutyl phthalate containing up to 10 weight % phthalic anhydride is suggested in U.S. Pat. No.
REFERENCES:
patent: 2638481 (1953-05-01), Nachod
patent: 2893924 (1959-07-01), Courtier
patent: 3040059 (1962-06-01), Hoyte
patent: 3818680 (1974-06-01), Marquis
patent: 3850758 (1974-11-01), Smith et al.
patent: 3891680 (1975-06-01), Katsumoto et al.
patent: 4071540 (1978-01-01), Marquis
patent: 4118403 (1978-10-01), White
patent: 4192807 (1980-03-01), Broecker et al.
patent: 4584419 (1986-04-01), Sharif et al.
patent: 4767869 (1988-08-01), Harrison et al.
patent: 4919765 (1990-04-01), Wilkes et al.
patent: 4945173 (1990-07-01), Wood
patent: 5254758 (1993-10-01), Hiles et al.
patent: 5310954 (1994-05-01), Hiles et al.
patent: 5347021 (1994-09-01), Taylor et al.
Abstract for South African Patent No. 80/1247, South African Joernaal, Mar., 1981, p. 102.
Hiles Andrew George
Tuck Michael William Marshall
Wood Michael Anthony
BASF - Aktiengesellschaft
Owens Amelia
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