Shaped body comprising an aluminosilicate and aluminium oxide and process for the continuous preparation of methylamines
View Patent ↗Shaped body comprising an aluminosilicate and aluminum oxide, wherein the shaped body has a molar Al/Si ratio in the range from 10 to 30 and an at least bimodal pore distribution for pores having a diameter of greater than 1 nm, with the volume of the pores of the shaped body having a diameter of greater than 10 nm corresponding to at least 40% of the total pore volume of the shaped body, process for producing it and process for the continuous preparation of methylamines by reaction of methanol and/or dimethyl ether with ammonia in the presence of a heterogeneous catalyst, wherein the abovementioned shaped bodies are used as catalyst.
1. A shaped body comprising an aluminosilicate and aluminum oxide, wherein the shaped body has a molar Al/Si ratio in the range from 10 to 30 and an at least bimodal pore distribution for pores having a diameter of greater than 1 nm, with the volume of the pores of the shaped body having a diameter of greater than 10 nm corresponding to at least 40% of the total pore volume of the shaped body.
2. The shaped body according to claim 1 which has a molar Al/Si ratio in the range from 11 to 26.
3. The shaped body according to claim 1 which has a bimodal pore distribution for pores having a diameter of greater than 1 nm.
4. The shaped body according to claim 1 , wherein the volume of the pores of the shaped body having a diameter of greater than 10 nm corresponds to at least 50% of the total pore volume of the shaped body.
5. The shaped body according to claim 1 which has a BET surface area of ≧50 m 2 /g.
6. The shaped body according to claim 1 which has a BET surface area in the range from 100 to 250 m 2 /g.
7. The shaped body according to claim 1 which comprises from 0.01 to 1.75% by weight of sodium, from 0.01 to 1.75% by weight of potassium, from 0.01 to 0.35% by weight of titanium and from 0.01 to 0.35% by weight of iron, in each case based on the total weight.
8. The shaped body according to claim 1 which is an extrudate having a length:diameter ratio of ≧1.
9. The shaped body according to claim 1 which has a cutting hardness of ≧10 newton (N).
10. The shaped body according to claim 1 , wherein the aluminosilicate is a clay.
11. The shaped body according to claim 1 , wherein the aluminosilicate is a kaolin.
12. The shaped body according to claim 1 , wherein the aluminosilicate is kaolinite.
13. The shaped body according to claim 1 , wherein the aluminum oxide is gamma-Al 2 O 3 .
14. The shaped body according to claim 13 , wherein aluminum hydroxide or aluminum oxide/hydroxide (boehmite) is used as precursor for the gamma-aluminum oxide.
15. The shaped body according to claim 1 , wherein the proportion of aluminum oxide in the shaped body is ≧50% by weight.
16. A process for producing a shaped body according to claim 1 , comprising
(I) preparation of a mixture comprising the aluminosilicate, the aluminum oxide as binder, a pasting agent and a solvent,
(II) mixing and densification of the mixture,
(III) shaping of the densified mixture to give a shaped body.
(IV) drying of the shaped body and
(V) calcination of the dried shaped body.
17. The process according to claim 16 , wherein the mixture contains a pore former in (I).
18. The process according to claim 16 , wherein the proportion of aluminosilicate in (I) is chosen in a way, that it is between 1 and 30 wt.-% in the finished shaped body.
19. The process according to claim 16 , wherein the proportion of aluminum oxide in (I) is chosen in a way, that it is at least 50 wt.-% in the finished shaped body.
20. The process according to claim 16 , wherein shaping in (III) is carried out by extrusion.
21. The process according to claim 16 , wherein the calcination in (V) is carried out at a temperature in the range from 350 to 750° C. for a time in the range from 1 to 24 hours.
22. A process for the continuous preparation of methylamines by reaction of methanol or dimethyl ether with ammonia in the presence of a heterogeneous catalyst, wherein shaped bodies according to claim 1 are used as catalyst.
23. The process according to claim 22 , wherein the feed stream comprises methanol or dimethyl ether and ammonia together with at least one compound selected from monomethylamine, dimethylamine and trimethylamine.
24. The process according to claim 22 , wherein the molar N/C ratio in the feed mixture is in the range from 0.6 to 4.0.
25. The process according to claim 22 , wherein the reaction temperature is in the range from 250 to 500° C.
26. The process according to claim 22 , wherein the absolute pressure is in the range from 5 to 50 bar.
27. The process according to claim 22 , wherein the space velocity over the catalyst, expressed as mass of carbon-comprising compounds in the feed, calculated as methanol, per catalyst volume and time, is in the range from 0.1 to 2.0 kg/l/h.
28. The process according to claim 22 wherein the shaped bodies used as catalyst form a fixed bed comprising two, three, four or more different types of shaped bodies which differ in terms of their acidity.
29. The process according to claim 28 , wherein the shaped bodies used as catalyst form a fixed bed comprising two different types of shaped bodies located in separate zones.
30. The process according to claim 29 , wherein the difference between the molar Al/Si ratio of the two types of shaped bodies is in the range from 2 to 20.
31. The process according to claim 22 , wherein regeneration of the used catalyst is carried out by targeted burning-off of the deposits responsible for deactivation.