磷钨钼钒杂多蓝光度法测定钼的探索

本文研究了磷钨钼钒四元杂多酸及其还原产物杂多蓝的形成条件、光度性质、组成和在测定高速钢中高钼的应用。试验表明,磷钨钼钒杂多蓝光度法测定钼具有新颖性、高选择性、较高准确性和简便性,适于高速钢中>1％Mo的测定。     

分子内环加成的甾体全合成

近年来,分子内环加成反应已广泛用于甾体化合物全合成,其主要一步是由取代的苯并环丁烯热裂而成的5,6-二亚甲基-1,3-环己二烯发生区域专一和立体选择性的环加成反应,构成甾体骨架。现在用此法已合成了一系列消旋和光学活性的甾体化合物。     

Study of the initial stages of alkoxo synthesis involving Ti(OBu)4 and cyclophosphites

The reactivities of cyclophosphite precursors in alkoxo syntheses involving titanium(iv) tetra(n-butoxide) were studied by ³¹P NMR and IR spectroscopy. 2-Diethylamido-4-methyl-1,3,2-dioxaphosphinane and 4-ethyl-2,6,7-trioxaphosphabicyclo[2.2.2]octane in benzene are inert toward Ti(OBu)₄. Gelation is accompanied by hydrolysis 2-diethylamido-4-methyl-1,3,2-dioxaphosphinane to give the corresponding hydrophosphoryl compound, while 4-ethyl-2,6,7-trioxaphosphabicyclo[2.2.2]octane remains intact during gelation.     

Structure-Activity Relationship of Insecticidal Steroids. III. Δ4,7-6-Ketosteroids

The toxicity of steroids 1-11 for colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by contact-intestinal treatment. Active insect-growth regulators were found among the studied compounds.     

微合金钢中稀土对沉淀相和性能的影响

在Nb(Ti,V）微合金钢中，主要沉淀相分别为Nb(C,N),(Nb,Ti)(C,N)和V（C，N）。稀土降低沉淀相完全溶解的温度，增大奥氏体中沉淀相析出的孕育期，降低析出速率，抑制奥氏体中沉淀相的析出，在铁素体相区，稀土提高沉淀相的析出速率和数量，促进沉淀相的析出，其中稀土对铌沉淀相析出的作用影响最强。锻态钢中，稀土有促进细化球化析出相的作用，随稀土含量增加，沉淀相析出数量增加，但过量稀土，促进作用又减弱，稀土在保持微合金钢强度的情况下，显著改善其冲击韧性，尤其是低温韧性，微合金钢中添加适量稀土可获得更佳的综合性能。     

三碘化钐促进的α, α'-二(取代亚苄基)环戊酮的简便合成

在SmI3作用下和中性室温的条件下, 环戊酮能与醛缩合, 得到几乎定量产率的α, α'-二亚苄基环戊酮; 但对环己酮, 产率仅在20%左右。     

镧系与邻氨基苯甲酸型Schiff碱配合物的合成、表征及催化活性

本文合成2,4-二羟基苯甲醛缩邻氨基苯甲酸Schiff碱(H~3L),以改进的合成方法得到此配体与镧系元素形成的九种新配合物.经分析确定其组成[Ln(H~2L)~2NO~3],(Ln=La、Pr、Nd、Sm、Gd、Dy、Ho、Er、Yb.以热重-差执分析、紫外、红外光谱以及核磁共振谱等表征,证明Schiff碱具有稳定的分子内氢键并以三卤形式同镧系离子形成稳定的共轭双六元螯合环.经研究表明,此系列配合物对甲基丙烯酸甲酯的聚合有明显的催化活性.     

Synthesis and characterization of surface-cyanofunctionalized poly (N-isopropylacrylamide) latexes

 A series of P[N-isopropylacrylamide (NIPAM)] latexes with different contents of cyano groups were successfully prepared by either seeded or shot-growth polymerizations of an aqueous solution containing acrylonitrile (AN) onto a seed P[NIPAM] latex, respectively, and further characterized by FT-IR, ¹H-NMR, elemental analysis, as well as by quasielastic light scattering (QELS) and scanning electron microscopy (SEM). All prepared surface-cyanofunctionalized P[NIPAM] latexes exhibited the same range of lower critical solution temperature (LCST) as a pure P[NIPAM] latex. The shot polymerization process proved more efficient at yielding cyano derivatized latexes than the seeded polymerization technique. The amount of incorporated cyano groups onto the particles was determined with a good correlation both by ¹H-NMR and elemental analysis. The higher the amount of initially introduced AN monomer in the reaction mixture, the more cyano groups were incorporated onto the particles. The surface of the particles with high content of cyano groups appeared quite rough by SEM in comparison with that of the pure P[NIPAM] particles. Received: 25 February 1998 Accepted: 23 June 1998     

P-507回流萃取法富集镥的研究——Ⅰ.P-507萃取分离镱镥混合稀土的性能

本文研究了2-乙基己基膦酸单2-乙基己基酯(P-507)在盐酸和硝酸体系中萃取镱镥混合稀土的性能。说明P-507在硝酸体系中的萃取分离系数较其在盐酸体系中高,而在盐酸体系中有更高的反萃效率。与二(2-乙基己基)磷酸(P-204)相比,P-507具有萃取酸度低、易反萃和不易乳化的优点。我们还确定了回流萃取法分离镥镱的基本参数,表明P-507是一种新型的分离重稀土的良好萃取剂。     

火花激发原子发射光谱分析不锈钢线材

火花激发原子发射光谱法应用于直径小于8mm的不锈钢线材的分析，对此类试样应用了一种特制的夹具，用块状标准样品制作工作曲线。由于线状试样和块状标准样品之间的形状差异所产生的系统不确定度借采用同类型标样作校正，对共存元素的相互干扰也采用了相应的校正方法。其它分析条件，包括严格的制样工序，氩气的纯度要求及其流量控制，以及光源的最佳条件等，作了深入的试验。按所提出的方法测定了不锈钢线材试样中碳、硅、锰、磷、硫、铬、镍及钛等8个元素。经校正后的结果与化学法测得结果相符。