Title : Dehydration dimerization of methano
Abstract:
Possible use of DME (dimethyl ether) as a clean energy source, implies a sharp increase in the production of this compound. Combination preparation with methanol to DME by dehydration improves the conversion of synthesis gas in a single pass over the catalyst with 15 % (preparation CH3OH) to almost 90 %. For this purpose, use a mechanical mixture of catalysts for methanol production from synthesis gas and dehydration to DME. Given the nature of the acid catalysts in the dehydration of alcohols, ethers, for dehydration of methanol were used and HSZM HY-5 zeolite catalysts. From table , it follows that the conversion of methanol to HSZM-5 is accompanied by formation of substantially hydrocarbon products, but the catalyst is not stable, and for 30 minutes at 360 °C reduces its activity from 75.6 % to 8 %.Despite the stability, selectivity of the catalyst for both of DME and hydrocarbons is low. Positive results in the conversion of methanol exhibit zeolite catalysts impregnated with phosphoric acid.
Table. The conversion of methanol on zeolite catalysts modified H3PO4. T = 300 °C, V = 3 h-1
|
Time, min |
Composition of the reaction mixture, % C |
||||
|
CH4 |
åC2 + = |
åC2 + |
DME |
CH3OH |
|
|
HY + Al2O3 |
|||||
|
15 |
1.7 |
14.8 |
5.7 |
56.5 |
21.3 |
|
120 |
1.6 |
16.5 |
4.5 |
55.8 |
21.6 |
|
|
HZSM-5 + Al2O3 |
||||
|
15 |
2.4 |
60.85 |
21.84 |
10.6 |
24.4 |
|
120 |
- |
- |
- |
7.4 |
92.0 |
|
|
5% P2O5 / HY + Al2O3 |
||||
|
120 |
2.6 |
0.25 |
0.23 |
95.7 |
1.25 |
|
|
5% P2O5 / HZSM-5 + Al2O3 |
||||
|
15 |
2.8 |
60.75 |
18.1 |
10.6 |
7.8 |
|
120 |
2.5 |
60.8 |
21.6 |
10.8 |
4.3 |
As seen from table, HZSM-5 catalyst in this case becomes stable conversion of methanol to hydrocarbons and cannot create a catalyst having high activity and selectivity in the dehydration of methanol to DME based on Y zeolite. Moreover, as can be seen from the graph , Y-containing catalyst retains its activity even at space velocities greater than 10 h-1, i.e. it has high productivity, it is very important not only for the direct conversion of syngas to DME, but regulation methanol/DME by simply changing the amount of load of a dehydrating catalyst.
Publications:1.Rustamov, M.I. Dehydration of methanol on zeolite-containing catalysts / M.I. Rustamov, N.N. Piriev, F.A. Babayeva // Chemistry and Technology of Fuels and Oils,-2010, V. 46, ? 1, -p. 58-62. 2.Abasov, S.I. Conversion to hydrocarbons on modified zeolites y and ZSM-5 / S.I Abasov, F.A. Babayeva, B.B. Guliyev, N.N. Piriyev, M.I. Rustamov .Theoretical and Experimental Chemistry, – Russian: – 2013, –v. 49, ? 1, – p. 55-59.
