The catalytic performance of commonly used heteropolyacids (H

3

PW

12

O

40

H

4

SiW

12

O

40

and H

3

PMo

12

O

40

) for the synthesis of 4

4'-methylenedianiline (4

4'-MDA) from aniline and formaldehyde was evaluated and the result showed that H

4

SiW

12

O

40

with moderate acid strength exhibited the best catalytic performance. Then H

4

SiW

12

O

40

@MIL-100(Fe) was prepared by encapsulating H

4

SiW

12

O

40

within the pores of MIL-100(Fe) to facilitate its recovery and reuse. The prepared H

4

SiW

12

O

40

@MIL-100(Fe) was characterized by means of FT-IR

N

2

adsorption-desorption

XRD

TG and then the catalytic performance was evaluated. The result showed that H

4

SiW

12

O

40

was highly dispersed in the pores of MIL-100(Fe)

and both the Keggin structure of H

4

SiW

12

O

40

and the crystal skeleton structure of MIL-100(Fe) could be effectively preserved. Furthermore

H

4

SiW

12

O

40

@MIL-100(Fe) showed exce

llent catalytic performance under the following reaction conditions:a molar ratio of aniline to formaldehyde=5

a mass ratio of catalyst to formaldehyde=1.2

a reaction temperature of 120℃ and a reaction time of 6 h. Under the above reaction conditions

the conversion of aniline was 41.1%

and the yield and selectivity of 4

4'-MDA were 81.6% and 79.2%

respectively. Unfortunately

an appreciable loss in the catalytic activity of the recovered H

4

SiW

12

O

40

@MIL-100(Fe) was observed because of the blocking of the pores and the change of the acidity resulted from the adsorption of alkaline organics such as aniline and 4

4'-MDA. The adsorbed alkaline organics could be cleaned up when the recovered catalyst was washed by methanol and DMF. Then the catalyst was effectively reused up to three cycles without much loss in its activity.