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New well‐defined brush polypyromellitimides with n‐octyloxy and n‐dodecyloxy side chains were prepared by two‐step polycondensations of 3,6‐di(n‐alkyloxy)pyromellitic dianhydrides with various conventional aromatic diamines. Their structures and properties were investigated and compared with those of polyimides without the side chains. The alkyloxylated poly(amic acid)s had inherent viscosities of 0.45–1.09 dL/g. The polyimides showed enhanced solubility in organic solvents and had layered structures in the solid state. As the side‐chain length increased from n‐octyloxy to n‐dodecyloxy, the extent of layered structure formation increased, whereas the glass‐transition temperature and thermal resistance decreased. As for the liquid‐crystal (LC) aligning ability measured with 4‐n‐pentyl‐4′‐cyanobiphenyl on rubbed thin‐film surfaces, all the side‐chain polyimides revealed homogeneous LC alignment parallel to the rubbing direction with distinctively higher pretilt angles than those of the polyimides without the side chains. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3130–3142, 2004

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ZnMe III FeO 4 catalysts with different trivalent metal (Me III = Fe, Al, Cr, Mn, and Co) were prepared by a co-precipitation method, and were applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of ZnMe III FeO 4 catalysts was confirmed by XRD and ICP-AES analyses. Catalytic performance of ZnMe III FeO 4 catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of trivalent metal (Me III ). Acid properties of ZnMe III FeO 4 catalysts were measured by NH 3 -TPD experiments, with an aim of correlating the catalytic performance with the surface acid property of the catalysts. It was revealed that yield for 1,3-butadiene increased with increasing surface weak-acid density of ZnMe III FeO 4 catalyst. Among the catalysts tested, ZnFeFeO 4 catalyst with the largest surface weak-acid density showed the best catalytic performance in the oxidative dehydrogenation of n-butene.

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A series of metal ferrite (Me II Fe 2 O 4 ) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (Me II = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH 3 -TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing surface acidity of the catalyst. Among the catalysts tested, ZnFe 2 O 4 catalyst with the largest surface acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.

Pure bismuth molybdate (c-Bi 2 MoO 6 ) and multicomponent bismuth molybdate (Co 9 Fe 3 Bi 1 Mo 12 O 51 ) catalysts were prepared by a co-precipitation method, and were applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene. The Co 9 Fe 3 Bi 1 Mo 12 O 51 catalyst showed a better catalytic performance than the c-Bi 2 MoO 6 catalyst in terms of conversion of n-butene and yield for 1,3-butadiene, indicating that the multicomponent bismuth molybdate was more efficient than the pure bismuth molybdate in the oxidative dehydrogenation of n-butene. It was revealed that the crucial factor determining the catalytic performance of Bi-Mo-based catalyst in the oxidative dehydrogenation of n-butene is not the amount of oxygen in the catalyst involved in the reaction (oxygen capacity) but the intrinsic mobility of oxygen in the catalyst involved in the reaction (oxygen mobility). The enhanced catalytic performance of Co 9 Fe 3 Bi 1 Mo 12 O 51 was due to its facile oxygen mobility.