Tri(4-methoxybenzyloxyl)(pentamethylcyclopentadienyl)titanium/Modified MAO Catalyzed Polymerization of 1-Butene

Tri(4-methoxy-1-benzyloxyl)(pentamethylcyclopentadienyl)titanium(Cp*Ti(OBzOCH3)3) in conjunction with modified methylalumoxane(mMAO) was an efficient catalyst for the living polymerization of butene-1. The steric and highly electron-releasing nature of the catalyst was probably responsible for the resulting polymers with high molecular weight and narrow molecular weight distribution(Mw/Mn=1.25 to 1.36). The effects of polymerization conditions on the catalytic activity, molecular weight and stereo-regularity of the products were investigated in detail. Especially, the content of TMA in MAO used in polymerization of butene-1 had a profound influence on polymer microstructure. The structural properties of the polybutene-1 product were characterized by 13 C NMR, GPC, DSC and WAXD. The results indicated that the polybutene-1 was isotacticity-rich(at 0 ℃, [mmmm] reached up to 60.3%) and the relative content of methylene pentad sequences [mmmm] of the polymer increased with a decreasing temperature.

栀子柏皮汤3种方法提取液指标成分的比较

目的:比较栀子柏皮汤3种方法(半仿生提取法、醇提取法、水提取法)提取液的成分,为栀子柏皮汤提取提供实验依据。方法:在饮片规格、溶剂用量、以及提取、滤过、浓缩设备相同的条件下,将栀子柏皮汤分别以半仿生提取法、醇提法、水提法3种方法提取,以HPLC测定3种方法提取液中主要有效成分栀子苷、盐酸小檗碱、甘草次酸含量;以紫外分光光度法测定总生物碱含量;将栀子苷、盐酸小檗碱、甘草次酸、总生物碱含量以及相对分子质量≤1 000 Da提取物得率共5个指标测定结果经标准化处理后进行加权求和,得综合评判值Y并进行比较,Y大者为优。结果:栀子柏皮汤3种方法提取液的综合评价值Y大小顺序依次为:半仿生提取液>醇提液>水提液。结论:栀子柏皮汤3种提取方法中,以半仿生提取法最佳。