Method of preparing isobutylene

[0031] This example illustrates an example of the selective hydrogenation and isomerization reaction of the tail gas feedstock 1 of the butadiene extraction unit.

[0032] The composition of tail gas raw material 1 of the butadiene extraction unit is shown in Table 1.

[0033] Take titanium oxide content 15.2wt%, metal palladium content 0.3wt%, specific surface area is 89m 2 / g, Pd / TiO with a pore volume of 0.51ml / g and a most probable pore diameter of 130 angstroms 2 -Al 2 o 350 milliliters of the catalyst was loaded in the reactor, and the reaction pressure was 1.5 MPa, the temperature was 110° C., and the hydrogen flow rate was 40 milliliters / min. The reduction was carried out for 8 hours.

[0034] When the reactor inlet temperature is 30°C, the reaction pressure is 1.2MPa, the molar ratio of hydrogen to olefin is 1.0, and the liquid volume space velocity is 10h -1 , feed the raw material 1 under the condition that the circulation ratio is 9:1 (the volume ratio of the h...

[0043] This example illustrates the results of selective hydrogenation of butadiene extraction tail gas using palladium-based catalysts with different contents.

[0044] Take titanium oxide content 16.5wt%, metal palladium content 0.2wt%, specific surface area is 87m 2 / g, Pd / TiO with a pore volume of 0.48ml / g and a most probable pore diameter of 110 angstroms 2 -Al 2 o 3 Catalyst 50 milliliters are loaded in the reactor, feed gas and reaction condition are the same as embodiment 1, and the result of selective hydrogenation is shown in Table 4. The calculated yield of n-butene is 38.6%, the yield of trans-2-butene is 43.43%, and the yield of cis-2-butene is 5.02%.

[0045] The results of the isomerization reaction are shown in Table 5. The calculated butene conversion rate is 38.42%, the isobutene selectivity is 89.67%, and the isobutene yield is 34.23%.

[0046] Table 4 Composition of hydrogenation product 2

[0047]

[0048] Table 5 Composition of isomerization prod...

[0051] This example illustrates an example of the selective hydrogenation and isomerization reaction of the tail gas feedstock 2 of the butadiene extraction unit.

[0052] The two catalysts and reaction conditions are the same as those in Example 1, except that the raw material composition of the butadiene extraction tail gas is changed, as shown in Table 6.

[0053] The results of selective hydrogenation are shown in Table 7, and the calculated yield of n-butene is 43.12%, the yield of trans-2-butene is 33.51%, and the yield of cis-2-butene is 16.35%.

[0054] The results of the isomerization reaction are shown in Table 8. The calculated butene conversion rate is 39.15%, the isobutene selectivity is 91.17%, and the isobutene yield is 35.70%.

[0055] Table 6 Composition of Raw Material 3

[0056]

[0057] Table 7 Composition of hydrogenation product 3

[0058]

[0059] Table 8 Composition of isomerization product 3

[0060]

[0061] As can be seen from Examples 1 ...