Method of producing 1,4-butanediol and tetrahydrofuran from fura

Details Method of producing 1,4-butanediol and tetrahydrofuran from fura Method of producing 1,4-butanediol and tetrahydrofuran from fura

1997-09-16

1999-05-18

Owens, Amelia

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

568865, C07D307/08

Patent

active

059051590

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to a process for the preparation of 1,4-butanediol/tetrahydrofuran (THF) from furan.
In Russian Patent 114,928, furan in neutral or slightly acidic, aqueous solution (addition of formic acid) is hydrogenated over nickel catalysts to give a mixture of tetrahydrofuran, 1,4-butanediol and small amounts of n-butanol. The yields of butanediol/THF are modest, with low conversions. J. M. Watson, Ind. Eng. Chem. Prod. Res. Develop. 12 (4) (1973), 310-311, describes the same reaction over nickel catalysts but in the presence of acetic acid. U.S. Pat. No. 4,146,741 likewise describes the hydrogenation of furan to butanediol over nickel catalysts, which may also contain copper, but in the presence of aqueous dicarboxylic acid solutions. It is also stated that, if the acidity of the reaction system is too low, virtually only THF and only a small amount of diol is formed. In U.S. Pat. No. 4,475,004, halogenated carboxylic acids are used in addition to nickel catalysts. In the absence of these halogenated carboxylic acids, butanediol is formed only in traces. The same halogenated carboxylic acids are also used in U.S. Pat. No. 4,476,332, in combination with ruthenium catalysts. Without these acid promoters, no butanediol is formed.
The abovementioned methods for the preparation of 1,4-butanediol and THF from furan have the disadvantage that they generally give only low yields of butanediol and result in the formation of byproducts (e.g. butanediol diacetate) which are difficult to separate from the desired product. In general, it is true that one catalyst component (carboxylic acid) makes it much more difficult to carry out continuously the reactions described above is on an industrial scale. This is because, on the one hand, precautions must be taken to avoid corrosion of the plants (the use of halocarboxylic acids is virtually ruled out). On the other hand, the acids must be discharged with the product stream and continuously recycled after expensive isolation. Since a certain degree of esterification always takes place in the presence of an acid and of an alcohol (butanediol), some of the carboxylic acid must be continuously replenished. Moreover, hydrogenation of the acid is to be expected during the reaction, likewise leading to continuous losses of carboxylic acids.
It is an object of the present invention to provide a process which on the one hand leads to high selectivity with respect to butanediol/THF and on the other hand manages without promoters, such as the stated carboxylic acids.
We have found that this object is achieved by a process for the preparation of 1,4-butanediol/THF from furan, which is converted as a reaction mixture with water and in the presence of hydrogen but in the absence of a water-soluble acid or carboxylic acid, at 20-300.degree. C. and 100 kPa 30 MPa (1-300 bar) over a hydrogenation catalyst. This hydrogenation catalyst contains at least one of the elements of subgroup I, V, VI, VII or VIII of the Periodic Table of Elements in the form of a compound, preferably as an oxide, or in elemental form, the additional restriction that it does not contain nickel alone being applicable.
In carrying out the novel process, furan is reacted with water in general in a molar furan/water ratio of from 1:0.1 to 1:100, preferably from 1:0.2 to 1:50, particularly preferably from 1:1 to 1:10, to give 1,4-butanediol/THF. This is effected in the presence of hydrogen and a hydrogenation catalyst at in general 100 kPa-30 MPA (1-300 bar), preferably 500 kPa-20 MPa (5-200 bar), particularly preferably 1-15 MPa (10-150 bar), and at from 20 to 300.degree. C., preferably from 40 to 230.degree. C., particularly preferably from 80 to 200.degree. C.
In the novel process, the ratios of the yields of butanediol to those of THF are in general 0.1-40, preferably 0.2-35, particularly preferably 0.5-25, based on the mass.
In general, all catalysts which are suitable for the hydrogenation of carbonyl groups and contain at least one of the elements of subgroup I, V, VI, VII or VIII of the perio

REFERENCES:
patent: 3021342 (1962-02-01), Manly
patent: 4146741 (1979-03-01), Prichard
patent: 4475004 (1984-10-01), Nalepa
patent: 4476332 (1984-10-01), Nalepa
Ind. Eng. Chem. Prod. Res. Dev., vol. 12, No. 4, 1973.

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