Process for the conversion of 1,4 butynediol to 1,4 butenediol

Details Process for the conversion of 1,4 butynediol to 1,4 butenediol Process for the conversion of 1,4 butynediol to 1,4 butenediol

2000-11-20

2002-07-16

Richter, Johann (Department: 1621)

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

Organic compounds

Oxygen containing

C568S861000

Reexamination Certificate

active

06420615

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for the conversion of 1,4 butynediol to 1,4 butenediol by selective liquid phase hydrogenation. More particularly, the present invention relates to a process for the conversion of 1,4 butynediol to 1,4 butenediol in a basic medium using a novel noble metal containing catalyst.
BACKGROUND OF THE INVENTION
1,4 butenediol is a useful intermediate in the production of pesticide, insecticide and vitamin B
6
. Being an unsaturated diol it can be used in the synthesis of many organic products such as tetrahydrofuran, n-methyl pyrrolidione, &ggr;-butyrolactone, etc. It is also used as an additive in the paper industry, as a stabiliser in resin manufacture, as a lubricant for bearing systems and in the synthesis of allyl phosphates.
Prior art discloses the use of a number of catalysts for the manufacture of 1,4 butenediol by the hydrogenation of 1,4 butynediol. Most of the prior art patents are based on a combination of palladium with one or more mixed compounds of copper, zinc, calcium, cadmium, lead, alumina, mercury, tellurium, gallium, etc. GB A 871804 describes the selective hydrogenation of acetylinic compound in a suspension method using a Pd catalyst which has been treated with the salt solutions of Zn, Cd, Hg, Ga, Th, In, or Ga. The process is carried out at milder conditions with 97% selectivity for cis 1,2-butenediol and 3% to the trans form. Moreover, use of organic amines have been suggested as promoters in the catalyst system.
U.S. Pat. No. 2,681,938 discloses the use of a Lindlar catalyst (lead doped Pd catalyst), for the selective hydrogenation of acetylinic compounds. The drawback of this process is the use of additional amines such as pyridine to obtain good selectivity for 1,4 butenediol.
German patent DE 1, 213, 839 describes a Pd catalyst doped with Zn salts and ammonia for the partial hydrogenation of acetylinic compounds. However, this catalyst suffers from the drawback of short lifetime due to poisoning.
German patent application DE A 2, 619, 660 describes the use of Pd/Al
2
O
3
catalyst that has been treated with carbon monoxide for the hydrogenation of butynediol in an inert solvent. The disadvantage of this catalyst is that is treated with carbon monoxide gas which is highly toxic and difficult to handle.
U.S. Pat. No. 2,961,471 discloses a Raney nickel catalyst useful for the partial hydrogenation of 1,4 butynediol. The catalyst of this process gives a low selectivity for 1,4 butenediol. Another U.S. Pat. No. 2,953,604 describes a Pd containing charcoal and copper catalyst for the reduction of 1,4 butynediol to 1,4 butenediol with 41% selectivity for 1,4 butenediol. However, this process results in the formation of a large number of side products and is therefore undesirable.
U.S. Pat. No. 4,001,344 discloses the use of palladium mixed with &ggr;-Al
2
O
3
along with both zinc and cadmium or either zinc or cadmium together with bismuth or tellurium at 65° C. to 72° C. and 4-12.5 bars hydrogen pressure for the preparation of 1,4 butenediol by the selective hydrogenation of 1,4 butynediol. However, a large number of residues are formed (7.5-12%) which lowers the selectivity of 1,4 butenediol to 88%.
U.S. Pat. Nos. 5,521,139 and 5,728,900 describes the use of a Pd containing catalyst for the hydrogenation of 1,4 butynediol to prepare 1,4 butenediol. The catalyst used is a fixed bed catalyst prepared by applying Pd and Pb or Pd and Cd successively by vapor deposition or sputtering to a metal gauze or a metal foil acting as a support. In this process also the selectivity obtained for cis 1,4 butenediol is 98%. The disadvantage of this process is that a trans butenediol with residues are also obtained.
All the above catalysts for the hydrogenation of butynediol to butenediol suffer from disadvantages such as they contain more than two metals along with other promoters such as organic amines. Their preparation becomes cumbersome and all the reported catalysts do not give complete selectivity for the desired product 1,4 butenediol. The formation of side products and residues have also been reported which affect the efficiency of the process and the recovery of pure 1,4 butenediol is difficult. Another disadvantage that prior art catalysts suffer from is short life due to fast deactivation.
The prior art literature shows that the catalysts used for the hydrogenation of 1,4 butynediol are mainly palladium or nickel based catalysts. There is no disclosure or report on the use of platinum based catalysts or catalysts containing a combination of palladium and nickel for the hydrogenation of 1,4 butynediol to prepare 1,4 butenediol.
It is therefore important to obtain and/or develop catalysts that overcome the disadvantages of prior art catalysts used in the hydrogenation of 1,4 butynediol to 1,4 butenediol enumerated above.
OBJECTS OF THE INVENTION
The main object of the invention is to provide a process for the preparation of 1,4 butenediol by the hydrogenation of 1,4 butynediol that is cheap and efficient.
It is another object of the invention to provide a process for the preparation of 1,4 butenediol with 100% selectivity.
It is another object of the invention to provide a process for the conversion of 1,4 butynediol to 1,4 butenediol using a noble metal catalyst that optionally contains nickel, on a suitable support, under mild reaction conditions without poisoning.
It is a further object of the invention to provide a process for the conversion of 1,4 butynediol to 1,4 butendiol that shows 100% selectivity for the production of cis 1,4 butenediol.
It is a further object of the invention to provide a process for the conversion of 1,4 butynediol to 1,4 butenediol that uses a stable catalyst that is capable of being recycled a number of times without losing its activity and selectivity.
It is another object of the invention to provide a process for the preparation of 1,4 butendiol with 100% selectivity for the production of cis 1,4 butenediol by mere separation of the catalyst.
SUMMARY OF THE INVENTION
Accordingly the present invention relates to a process for the preparation of 1,4 butenediol comprising hydrogenation of an aqueous solution of 1,4 butynediol under stirring conditions, over a supported platinum, palladium and nickel catalyst in basic medium at a temperature in the range of 20-110° C. and H
2
pressure in the range between 200-700 psig till the reaction is completed, cooling the reaction mixture to room temperature and separating the catalyst by known methods to obtain 1,4 butenediol.
In one embodiment of the invention, the concentration of 1,4 butynediol in aqueous medium is in the range of 10-50%.
In another embodiment of the invention, the pH of the reaction mixture is maintained in the range of 8-10 by adding a base such as ammonia.
In a further embodiment of the invention, the temperature of the reaction is preferably in the range of 30-90° C.
In yet another embodiment of the invention, the catalyst is recycled 10 times without losing its activity or selectivity and the turn over number (TON) is 4×10
3
h
−1
.
In yet another embodiment of the invention, the catalyst is of the general formula AB(y)C(z) wherein A is a support comprising of carbonate of calcium or zeolite, B is platinum or palladium, y=0.2 to 10%, C is nickel and z=0 to 15.0%, with the proviso that when B is Pt, z=0.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention the catalyst is prepared by impregnating palladium or platinum precursor with support (such as CaCO
3
, MgCO
3
, BaCO
3
, or NH
4
—ZSM 5) in a basic medium (pH=7-12), stirred in water and heated in the temperature range of 60-120° C., preferably 70-90° C. The mixture is then reduced by adding a conventional reducing agent such as formaldehyde. The solution is stirred, filtered, washed and dried at a temperature in the range of 100-250° C., preferably 140-200° C. in static air for a period in the range of 5-12 hours.
The hydrogenation catalyst used in the process of the invention is of the general formula AB

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