With the increasing demand for synthetic rubber

the purification of 1

3-butadiene (C

4

H

6

) is of great industrial significance. Herein

the successful removal of

n

-butene (

n

-C

4

H

8

) and

iso

-butene (

iso

-C

4

H

8

) from 1

3-butadiene (C

4

H

6

) was realized by synthesizing a novel TaOF

5

2-

anion-pillared ultramicroporous material TaOFFIVE-3-Ni (also referred to as ZU-96

TaOFFIVE=TaOF

5

2-

3=pyrazine). Single-component adsorption isotherms show that TaOFFIVE-3-Ni can achieve the exclusion of

n

-C

4

H

8

and

iso

-C

4

H

8

in the low pressure region (0-30 kPa)

and uptake C

4

H

6

with a high capacity of 92.78 cm

3

·cm

-3

(298 K and 100 kPa). The uptake ratio of C

4

H

6

/

iso

-C

4

H

8

on TaOFFIVE-3-Ni was 20.83 (298 K and 100 kPa)

which was the highest among the state-of-the-art adsorbents reported so far. With the rotation of anion and py

razine ring

the pore size changes continuously

which makes smaller-size C

4

H

6

enter the channel while larger-size

n

-C

4

H

8

and

iso

-C

4

H

8

are completely blocked. The excellent breakthrough performance of TaOFFIVE-3-Ni shows great potential in industrial separation of C

4

olefins. The specific adsorption binding sites within ZU-96 was further revealed through the modeling calculation.