毛细管气相色谱法测定乙二醇中低浓度—缩二乙二醇和二缩三乙二醇

研究了一种毛细管气相色谱测定乙二醇中低浓度－缩二乙二醇和二缩三乙二醇的新分析方法。该法载气为氦气，样品经０．５３ｍｍ内径交联ＣＢＰ２０熔硅毛细管柱分离、ＦＩＤ检测和外标法定量。     

气相毛细管色谱法测定油酸

用甲醇－硫酸将油酸衍生为脂肪酸甲酯,用自制、耐高温气相毛细管柱分离测定,建立了快速分离测定油酸的方法。方法准确可靠、分析速度快。     

β—环糊精聚合物气相色谱固定相对异构体的分离研究

合成了非水溶性交联β－环糊精聚合物，超声波处理将其配成溶胶状固定液，用OV－17改性，采用超动态法、制备出柱效高、稳定性好的弹性石英毛细管柱，并对一系列异构体进行了色谱分离，对其分离机理作了初步探讨。     

毛细管气相色谱法测定苯基氯硅烷

用DB－1和SE－54两极不同极性的石英毛细血管色谱柱分离甲基苯基二氯硅烷（MePhSiCl2)和苯基三氯硅烷（PhSiCl3)。研究了桩型，固定相，载气种类，流速，柱温等变化对分离效果的影响，确定了最佳的分离条件。结果表明，用DB－1和SE－54毛细管柱均能使MePhSiCl2和PhSiCl3分离。用DB－1毛细管柱，H2和N2均能作载气，适宜柱长为50m；而使用SE－54柱时只能用H2作载气，10m长的柱子就足以使两者分离；用DB－1毛细管柱时，主要矛盾是分离；而用SE－54柱时，主要矛盾是分析时间。     

一硝基甲苯,二硝基甲苯的气相色谱分离方法

用气相色谱法对一硝基甲苯，二硝基甲苯异构体进行了含量测定，并给出了色谱分离操作条件。     

非水溶性β-环糊精聚合物气相色谱固定相对异构体的分离研究

合成了非水溶性交联β－环糊精聚合物，超声波处理使其成溶胶状固定液，用OV－17改性，采用超动态法，制备出柱效高、热稳定性好的弹性石英毛细管柱，并对一系列异构体进行了色谱分离，对分离机理作了初步探讨。     

现代分离技术在药品分析中的应用研究进展

药品分离是现代技术研究的一个重点方面,介绍3种现代技术在药品分离中应用。气相色谱法以气体为流动相的色谱方法,是一种检测挥发性有机化合物的功能强大的分离技术,可以用于分离分析易挥发物质,作为重要的分离分析方法之一,已经成为药物含量测定的方法。高效液相色谱法是以液体为流动相,对复杂样品进行分离分析,在中药等复杂体系的成分分离中发挥极其重要的作用。毛细管电泳法通过电泳和分配行为差异实现分离,具有操作简单、分离效率高等优点。     

工业用95%乙醇分离及杂质峰的定性分析

采用气相色谱分离法,热导池检测器对工业用95%乙醇进行分离和杂质峰的定性分析。色谱条件:柱温140℃,汽化室温度200℃,检测器温度200℃,固定液选用聚乙二醇20000,三氯乙烯为溶剂等。结果表明,工业用95%乙醇的色谱峰分离效果非常理想,乙醇含量95%,水约5%。     

酚类产品组成的气相色谱测定方法

建立了酚类产品组成的气相色谱测定方法,使用4种类型的毛细管色谱柱对酚类产品进行分析,对测定条件进行优化,各组分的分离度均达到了1.3,准确度和精密度优于GB/T2601—1981和GB/T2604—1981及JIS标准,与ASTM标准接近。该方法适用于所有焦化酚类产品组成的分析。     

环己醇中环己酮和苯酚的气相色谱分离

采用混合固定相在实验条件下实现了环己烷，环己醇，环己酮，苯酚的气相色谱分离，能够满足己二酸生产工艺控制的需要。     

磷炔CH3-C≡P及其异构体的稳定性

采用B3LYP方法对CH3CP体系进行了量子化学计算。结果表明,CH3-C≡P在其体系中是热力学最稳定的结构。动力学理论研究表明,CH3CP的2种动力学稳定的异构体中CH3-C≡p已被实验证实,从理论上推测的另一种动力学稳定性较高的异构体HC≡C-PH2也在实验中可以检测到。     

Production of p‐toluenesulfonic acid by sulfonating toluene with gaseous sulfur trioxide

Toluene was sulfonated by gaseous sulfur trioxide to prepare p‐toluenesulfonic acid. The effects of reaction temperature and toluene conversion on the isomer selectivities and the dynamic viscosity of the reaction mixture in a well‐stirred tubular glass reactor of 4 cm diameter and 16 cm height were investigated. Lower selectivity to the m‐isomer was obtained at lower reaction temperature and lower conversion of toluene, whereas the selectivity to the p‐isomer seemed to be less affected by these parameters. With the increase in toluene conversion a sharp increase in viscosity of the reaction mixture was observed, which was attributed to the saturation of the toluenesulfonic acids dissolved in toluene. A pilot‐scale stainless steel jet loop reactor (JLR) of 0.3 m diameter and 4 m height with an external cooler was constructed and used for the continuous sulfonation of toluene. It was found that the JLR was very effective for the fast removal of the large amount of reaction heat, and selectivities to the p‐isomer around 85% and to the m‐isomer below 1.2% were obtained. © 2001 Society of Chemical Industry     

Synthesis,characterization and thermal properties of phenylene–disiloxane polymers obtained from catalytic cross‐dehydrocoupling polymerization of bis(dimethylsilyl)benzene isomers and water

Phenylene–disiloxane polymers were prepared from 1,4‐bis(dimethylsilyl)benzene and 1,3‐bis(dimethylsilyl)benzene with water in various ratios by catalytic cross‐dehydrocoupling polymerization. Each isomer showed almost equal reactivity in the polymerization as verified by the analysis of the composition by ¹H NMR. Crystallinity observed in the polymer obtained from the 1,4‐isomer was removed by incorporating a small amount of 1,3‐isomer. © 2001 Society of Chemical Industry     

Field and electroantennogram responses of the red-headed pine sawfly,Neodiprion lecontei (Fitch), to optical isomers of sawfly sex pheromones

Sawfly sex pheromones, the acetate and propionate esters of 3,7-dimethylpentadecan-2-ol, were field tested for activity towardNeodiprion lecontei (Fitch). Only the acetate form of the 2S,3S,7S isomer was active. Field catch decreased with the addition of the 2S,3R,7(R/S) acetate isomer sample. Electroantennogram recordings showed a positive correlation between response and degree to which the chirality of each isomer resembled the attractive isomer.     

Lethal effect ofcis- but nottrans-22-dehydrocholesterol on mouse fibroblast cells

cis- andtrans-22-dehydrocholesterol were incorporated into the culture medium for mouse fibroblast cells. Although neither isomer had an effect on sterol biosynthesis, thecis isomer inhibited cell growth and viability and increased Rb⁺ efflux from the cells. Thetrans isomer had no effect on growth and could replace exogenous cholesterol for growth of cells for which sterol biosynthesis was blocked by 25-hydroxycholesterol.     

Synthesis and properties of polyesterimides and their isomers

A new type of polyesterimide has been synthesized by polycondensation of a dicarboxylic acid containing an internal imide group with ethylene glycol. The dicarboxylic acid was synthesized by reacting aminobenzoic acid with trimellitic acid anhydride in N, N-dimethylformamide solution. Three isomeric (ortho, meta, and para) polyesterimides were prepared from the respective isomer of the dicarboxylic acid. The solubility characteristics, solubility parameters, solution viscosity behavior, density, crystallinity, and thermal properties of these three isomeric polyesterimides were discussed. Some generalizations about structure–property relationship in polyesterimides were also made. It was found that while the ortho and meta isomers of the polyesterimide are amorphous, the para isomer tends to be somewhat crystalline and consequently less soluble, even in polar solvents. The thermal behavior of the meta isomer resembles closely that of the para isomer. The thermal stability of these isomers follows the order para ≥ meta > ortho.     

Competitive hydrogenation rates of isomeric methyl octadecenoates

Hydrogenation rates of isomeric methyl octadecenoates were compared by reducing mixtures containing a small weight of one radioactively labeled isomer and a much larger weight of another unlabeled isomer. As hydrogenation proceeded, samples were removed for analysis by a gas chromatograph, coupled with an ionization chamber so that mass peaks measured reduction of the unlabeled isomer and radioactive peaks of the labeled isomer. The ratio of hydrogenation rates best fitting these data was calculated with a digital computer. Reductions were made at atmospheric pressure generally with either nickel at 140C or platinum at 50C. A few were made with palladium at 50C. Methyl oleate hydrogenated more rapidly than methyl elaidate and thecis-15-isomer more rapidly than oleate. Other variations among the positionalcis isomers investigated were small. Presented at the AOCS Meeting, San Francisco, April 1969.     

Zr-SBA-15催化苯酚甲醛高选择性合成邻位异构体双酚F

以P₁₂₃为模板剂,正硅酸乙酯为硅源,以硝酸氧锆为锆源,采用水热一步法合成了分子筛催化剂Zr-SBA-15,用XRD、BET、ICP、吡啶FT-IR、NH₃-TPD进行了分析表征,考察了不同Si/Zr摩尔比Zr-SBA-15催化苯酚、甲醛合成双酚F的催化活性,发现当Si/Zr摩尔比为20时催化活性较好。以Si/Zr摩尔比20的Zr-SBA-15为催化剂,在反应温度90℃、酚醛摩尔比30:1、催化剂与甲醛质量比1:1条件下反应240 min,双酚F收率达到83.5%,邻位异构体双酚F选择性高达92.5%,同时还提出了Zr-SBA-15高选择性催化苯酚、甲醛合成邻位异构体双酚F的反应机理。     

六溴环十二烷的合成研究

以环十二碳三烯(CDT)和溴素为原料,在乙醇、三氯甲烷混合溶剂中进行加成反应,合成六溴环十二烷阻燃剂。通过单因素实验,探讨了溶剂配比、滴加方式、反应物物质的量比、滴加时间等对六溴环十二烷各个异构体含量的影响,筛选出最佳的工艺条件为:m(乙醇):m(三氯甲烷)=1:1,滴加方式为溴素与CDT同时滴加,n(溴素):n(CDT)=3.5:1,滴加时间为8h,在该条件下收率为95%,γ异构体含量可达到80%。采用高效液相色谱对六溴环十二烷进行分析,检测α、β、γ各个异构体的含量,为最佳条件的选择提供依据。     

Skeletal isomerization of octadecane on bifunctional ZSM-23 zeolite catalyst

Octadecane was isomerized over three different Pt/H-ZSM-23 samples. The distributions of methylheptadecane and dimethylheptadecane skeletal isomers obtained on the Pt/ZSM-23 samples were very similar. Positional isomer distributions are fingerprints of the zeolite framework structure. The independence of skeletal isomer distributions from Al-gradients and particle size constitutes a strong argument in favor of pore-mouth catalysis.