Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1997-03-20
1998-02-03
Dentz, Bernard
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
502329, C07C 3118
Patent
active
057146446
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP95/02592, Jul. 4, 1995.
2-Butene-1,4-diol (referred to below as "butenediol") has been produced for some time on an industrial scale from 2-butyne-1,4-diol (referred to below as "butynediol"), which is produced on an industrial scale by the Reppe synthesis. Butenediol is required for some important crop-protection agents, pharmaceuticals and intermediates. It is of great importance that a very pure hydrogenation product is obtained, since product losses must be avoided and distillative removal of unhydrogenated butynediol and of butanediol formed by overhydrogenation is only possible in a complex procedure.
The catalytic hydrogenation of butynediol to butenediol is generally carried out batchwise using a suspension catalyst. In this process, hydrogen at 30.degree.-150.degree. C. and 1-20 bar is injected into a stirred reactor containing the butynediol solution and catalyst. The reaction is terminated when the stoichiometric amount of hydrogen has been taken up. Numerous proposals have been made regarding the catalysts, in particular palladium catalysts, and some have also been implemented in industry.
In order to achieve adequate selectivity, Pd/BaSO.sub.4 catalysts with addition of quinoline (DE 1 115 238), Pd/Al.sub.2 O.sub.3 catalysts with addition of carbon monoxide (DE 2 619 660) and Pd/Cu and Pd/Al.sub.2 O.sub.3 catalysts with addition of copper acetate (GB 832 141) have been proposed.
However, soluble additives are inconvenient to handle and cause problems during work-up. Metering in of CO, as described in DE 2619 660, requires additional technical complexity and should therefore be avoided.
According to information in patents, good results have also been achieved with the following catalysts: hydrogenation times were necessary for these hydrogenations.
DE 2 431 929 describes catalysts containing only 0.5% of Pd on Al.sub.2 O.sub.3 with zinc, cadmium, bismuth and tellurium doping. The catalysts have good selectivity, but have the disadvantage of containing carcinogenic or toxic constituents.
A particular difficulty arises if crude butynediol is to be employed in the selective hydrogenation without prior purification. This material having a pH of about 5 contains methanol, formaldehyde, formic acid and propargyl alcohol. It also contains catalyst constituents, such as Cu and Bi, from the butynediol synthesis. The catalyst thus also needs to have substantial tolerance to these constituents of the starting material, although it is known that both added copper (cf. DD 246 986) and added bismuth (cf. DE 2 431 929) affect the hydrogenation.
In spite of the extensive prior art, there is a desire for a further improvement in the process for the selective hydrogenation of butanediol and in the catalyst which can be used for this purpose. The invention has the object of solving the following problems or part-problems--individually or in combination:
1. No toxic or carcinogenic substances, such as, for example, compounds of tellurium or cadmium, should be employed in the preparation of the catalyst.
2. The highest possible selectivity should be achieved in order to minimize product losses, in particular due to overhydrogenation and acetal formation.
3. A high catalyst activity should be achieved in order to reduce the amount of catalyst employed, based on the amount of butynediol to be reacted.
4. Simple handling of the catalyst, in particular good filterability, should be achieved.
5. It should also be possible to carry out the selective hydrogenation using crude butynediol (in particular having a pH of 5).
6. It should also be possible to carry out the selective hydrogenation in the presence of one or more of the following contaminants: methanol, formaldehyde, formic acid, propargyl alcohol or Cu and/or Bi, which can originate, for example, from the butynediol synthesis.
7. Tolerance of the catalyst to constituents of the starting material.
These problems or part-problems of the invention are solved by means of processes and catalysts as defined in the claims. Preferred emb
REFERENCES:
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patent: 3119879 (1964-01-01), Hort et al.
patent: 3450776 (1969-06-01), Di Cio et al.
patent: 4001344 (1977-01-01), Hoffmann et al.
patent: 4021374 (1977-05-01), Petro et al.
patent: 4273944 (1981-06-01), Ohno et al.
patent: 4658071 (1987-04-01), Seufert et al.
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Derwent Abstract No. 81-82217D (English abstract of JP 56 12 0627, Sep. 22, 1981).
Graf Fritz
Irgang Matthias
Menger Volkmar
Miesen Ernest
Stops Peter
BASF - Aktiengesellschaft
Dahlen Garth M.
Dentz Bernard
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