Compound [Co 3(BTC)(HBTC)(H 2BTC)(C 2H 4O 2) 3]·3(DMF)·6(H 3O) was synthesized under mild conditions and its crystal structure was determined by using single crystal X-ray diffraction. The crystal structure was solved by direct method and refined by full-matrix least-square method. The crystal is monoclinic and belongs to space group Cc with a=2.645 3(5) nm, b= 1.670 4(3) nm, c=1\^821 6(4) nm, β=128.16(3) °, V=6.329(2) nm 3, Z=2 , D c=20.200 Mg/m 3, M r= 1 314.744, μ=10.274 mm -1, F(000) =38 226, GOF=0.99, R=0.094 1, ωR=0.257 3.
Silica mesoporous materials were synthesized and used as the supporting materials for immobilization of enzyme.Penicillin G acylase,an enzyme which was used to produce 6-APA in pharmaceutical industry,was immobilized in the mesoporous materials by the immersion method.The stabilities of the immobilized penicillin G acylase were studied.After incubation at 60 ℃ for 2 h,the activity of immobilized penicillin G acylase remained 80% in the best case.At higher or lower pH,the free enzyme was deactivated quickly,while the immobilized enzyme still retained active.The result of operational stability showed that the immobilized(enzyme) retained 70% of its initial activity after operating for 6 times.These results showed that the stabilities of immobilized penicillin G acylase,related to the pore size of mesoporous materials,were increased significantly compared with those of free enzyme.The improvement of stabilities of immobilized enzyme was significant when the pore size of the mesoporous materials matched the enzyme molecule size.
Silica mesoporous material MCFs with 16.0 nm pore sizes was prepared by using non-ionic block copolymers and the swelling agents, and was used as the support for the immobilization of enzyme. Penicillin G acylase, an enzyme, was assembled in the channel of MCFs by immersion method. The activity and stability of immobilized penicillin G acylase were studied. It was found that the activity and stability of the immobilized penicillin G acylase increased significantly compared to those of free enzyme. The optimum reaction temperature is 60 ℃. After incubation at 60 ℃ for 1 h, the activity of these immobilized penicillin G acylase remains 69%. These results showed that thermostability and durability on heating of the immobilized penicillin G acylase in MCFs was improved remarkably. The silica mesoporous material MCFs with 3-dimensional channel structure is a good support for the immobilization of enzyme.
Organic templates of as-synthesized siliceous,MCM-41 and SBA-15 can be effectively removed by oxidation treatment.The highly ordered mesostructures and surface properties of inorganic frameworks were retained after the template being removed.MCM-41 and SBA-15 obtained after oxidation treatment showed larger pores and richer silanol groups compared with those obtained by conventional calcinations at 550 ℃ in air.The removing ratios of templates of MCM-41 and SBA-15 were respectively 88% and 98%.
