Supported tantalum catalyst for the production of 1,3-butadiene
The invention relates to a process for the production of 1,3-butadiene from a feed comprising ethanol and acetaldehyde in the presence of a supported tantalum catalyst obtainable by aqueous impregnation of the support with a water-soluble tantalum precursor. Furthermore, the present invention relates to a process for the production of a supported tantalum catalyst, and the supported tantalum catalyst. Finally, the invention relates to the use of the supported tantalum catalyst for the production of 1,3-butadiene from a feed comprising ethanol and acetaldehyde to increase one or both of selectivity and yield of the reaction.
1. A process for the production of 1,3-butadiene, the process comprising
i) contacting a feed comprising ethanol and acetaldehyde with a supported tantalum catalyst to obtain a raw product comprising 1,3-butadiene,
wherein the catalyst is obtainable by a process comprising
a) preparing a water-soluble tantalum precursor by reacting one or more tantalum compound(s) in aqueous solution and under oxidative conditions,
b) aqueous impregnating a support with the water-soluble tantalum precursor obtained from step a),
c) drying, and
d) calcination.
2. The process of claim 1 , wherein the supported tantalum catalyst has a tantalum content, calculated as Ta 2 O 5 and based on the total weight of the catalyst, in a range of from 0.1 to 10 wt %.
3. The process of claim 2 , wherein the tantalum content is in a range of from 2 to 3 wt%.
4. The process of claim 1 , wherein the tantalum compound is selected from the group consisting of tantalum halides, tantalum hydroxide and tantalum oxalate.
5. The process of claim 4 , wherein the tantalum compound is tantalum (V) hydroxide.
6. The process of claim 1 , wherein the i) contacting takes place at a temperature in a range of from 200 to 500° C.
7. The process of claim 6 , wherein the temperature is in a range of from 250 to 450° C.
8. The process of claim 1 , wherein the i) contacting takes place at a weight hourly space velocity in a range of from 0.2 to 10 h −1 .
9. The process of claim 1 , further comprising ii) separating the raw product at least into a first portion comprising 1,3-butadiene, a second portion comprising acetaldehyde and a third portion comprising ethanol.
10. The process of claim 9 , wherein at least part of the second, of the third, or of the second and of the third portions is recycled into the feed.
11. The process of claim 1 , wherein the i) contacting takes place in a continuous flow fixed bed reactor.
12. A process for the production of a supported tantalum catalyst, comprising the steps of
a) preparing a water-soluble tantalum precursor by reacting one or more tantalum compound(s) in aqueous solution and under oxidative conditions,
b) aqueous impregnating a support with the water-soluble tantalum precursor obtained from step a),
c) drying, and
d) calcination.
13. The process of claim 12 , wherein the reacting in aqueous solution and under oxidative conditions comprises the presence of one or both of persulfate ion and hydrogen peroxide.
14. The process of claim 13 , wherein the reacting in aqueous solution and under oxidative conditions comprises the presence of hydrogen peroxide.
15. The process of claim 12 , wherein the reacting in aqueous solution is at a pH of greater than 7.
16. The process of claim 13 , wherein the water-soluble tantalum precursor is prepared by
a1) reacting said tantalum compound(s) with aqueous hydrogen peroxide, followed by reaction with one or both of aqueous ammonia and aqueous sodium hydroxide; or
a2) reacting said tantalum compound(s) simultaneously with aqueous hydrogen peroxide and one or both of aqueous ammonia and aqueous sodium hydroxide.
17. The process of claim 16 , wherein the weight ratio of tantalum to ammonia is in a range of from 3:1 to 1:1, wherein the weight ratio refers to tantalum as a metal and pure ammonia.
18. The process of claim 16 , wherein the weight ratio of tantalum to hydrogen peroxide is in a range of from 1:10 to 1:40, wherein the weight ratio refers to tantalum as a metal and pure hydrogen peroxide.
19. The process of claim 12 , wherein the support has a BET specific surface area in a range of from 130-550 m 2 /g.
20. The process of claim 19 , wherein the BET specific surface area is in a range of from 190 to 280 m 2 /g.
21. A supported tantalum catalyst, obtainable by the process of claim 8 .
22. The supported catalyst of claim 21 , wherein the support is selected from ordered and non-ordered porous silica supports, aluminosilicate supports and other porous oxide-supports and mixtures thereof.
23. The supported tantalum catalyst of claim 21 , further comprising caesium.
24. The supported tantalum catalyst of claim 23 , wherein the caesium content of the catalyst is calculated as Cs 2 O and based on the total weight of the catalyst, and wherein the weight ratio of Cs 2 O to Ta 2 O 5 in the catalyst is in a range of from 1:6 to 1:30.