A new quatemary ammonium heteropolyoxotungstant (cat.C) is prepared andcharacterized. And the cat.C also is an reaction-controlled phase-transfer catalyst The catalyticsystem of O_2/EAHQ (2-ethylanthrahydroquinone)/ca...A new quatemary ammonium heteropolyoxotungstant (cat.C) is prepared andcharacterized. And the cat.C also is an reaction-controlled phase-transfer catalyst The catalyticsystem of O_2/EAHQ (2-ethylanthrahydroquinone)/cat.c is used for the epoxidation of propylene.Under the optimal conditions, the yield of propylene oxide based on EAHQ is 84.1%, theselectivity for propylene oxide based on propylene is 99.8% and the conversion of propylene basedon EAHQ is 84.3%. The cat.c precipitates after the epoxidation reaction for easy separation.The cat C is stable enough to be recycled three times without any loss in selectivity.展开更多
Let S be a regular semigroup, S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S, if V（x）∩S°≠Ф. In this paper, some properties of this kind of semigroups are discus...Let S be a regular semigroup, S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S, if V（x）∩S°≠Ф. In this paper, some properties of this kind of semigroups are discussed. In particular, a construction theorem is obtained which contains some recent results in the literature as its special cases.展开更多
文摘A new quatemary ammonium heteropolyoxotungstant (cat.C) is prepared andcharacterized. And the cat.C also is an reaction-controlled phase-transfer catalyst The catalyticsystem of O_2/EAHQ (2-ethylanthrahydroquinone)/cat.c is used for the epoxidation of propylene.Under the optimal conditions, the yield of propylene oxide based on EAHQ is 84.1%, theselectivity for propylene oxide based on propylene is 99.8% and the conversion of propylene basedon EAHQ is 84.3%. The cat.c precipitates after the epoxidation reaction for easy separation.The cat C is stable enough to be recycled three times without any loss in selectivity.
文摘Let S be a regular semigroup, S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S, if V（x）∩S°≠Ф. In this paper, some properties of this kind of semigroups are discussed. In particular, a construction theorem is obtained which contains some recent results in the literature as its special cases.
