使用裂解气相色谱对几种阻燃聚丙烯材料热稳定性及阻燃机理的探讨

用裂解气相色谱（PyGC)考察了经三种类型阻燃剂（含磷、含溴、含溴和磷）改性的聚丙烯的热稳定性。利用PyGC-MS法分析不同样品的高温裂角产物,以此来推测阻燃材料受热分解时气相以及凝聚相所发生的反应,推断阻燃机理,分析影响阻燃效果的因素,为阻燃剂的开发提供有益参考。结果证实,它们都影响聚丙烯的热降解。溴系阻燃剂和磷系阻燃剂是分别从气相阻断、凝固相加速成炭实现阻止燃烧的,而磷-溴型阻燃剂同时具备单纯含磷或者含溴阻燃能力。     

电位法水质中氯溴碘的同时测定

氯溴碘三种离子共存时,总是互相干扰各自测定结果。近年来,Prokopov采用电位滴定及碘量法滴定完成氯溴碘的同时测定。这个方法较Belcher等早期提出的容量分析法简便,但所应用的碘量法测定碘离子操作仍嫌繁琐。本文采用电位法:1.用自制Ag-AgCl丝电极作指示电极,玻璃电极作参比电极,在90％丙酮介质中用标准Ag~+ 溶液电位滴定氯溴碘三种离子总量。2.用双氧水-8-羧基喹啉消除 Br~- 及I~- 后,在90％丙酮介质中电位滴定氯离子量。3.用     

气相色谱-质谱联用法测定塑料产品中的溴系阻燃剂

溴系阻燃剂是目前全世界范围内使用的主要阻燃剂,常用的有十溴联苯醚、四溴双酚A、四溴双酚A-双(2,3-二溴)丙醚、六溴环十二烷、三溴苯酚、十溴联苯乙烷等。溴系阻燃剂的分解温度大多在200~300℃左右,与各种高聚物的分解温度匹配,因此能在最佳时刻以气相及凝聚相同时起到阻燃作     

银电极上氯溴碘的零电流示波双电位滴定

用阴极射线示波器荧光屏上荧光点的突然位移指示银电极双电位滴定终点,具有灵敏度高、简便、经济、快速等特点,比经典双电位滴定法优越,还可用于氯溴碘的连续滴定。     

有机化合物中氯、溴元素的微量自动分析

本文报导了有机化合物中氯、溴元素的微量自动分析法.通过使用椭圆形的氧瓶和装在同一瓶中的银电极,使样品(3～5毫克)燃烧、吸收和库仑滴定能连续进行.每次测定约5分钟.测定误差小于0. 5%.     

溴系阻燃剂在环境及人体中的存在和代谢转化

溴系阻燃剂的广泛使用及其对环境和人体的危害,受到人们的广泛关注。本文简要介绍了在环境与生态系统及人体中存在的三种主要溴系阻燃剂：多溴联苯醚、六溴环十二烷和四溴双酚A,重点评述了它们在环境介质（污水、淤泥及沉积物）、生物体（微生物及动物）、人体中及光热作用下的代谢与转化,并详细介绍了其代谢途径及代谢产物。     

电位滴定法连续测定线路板裂解残渣中微量氯和溴

印刷电路板样品经热降解和去卤化处理后,所得试样残渣中残留的氯和溴离子用电位滴定法连续测定.采用硝酸银标准溶液作为滴定剂,滴定系在有一定量的硝酸钾存在的稀硝酸溶液中进行,滴定终点取滴定曲线上两离子突跃部分斜率的最大值处或其一次微分曲线上相应的最小值处.计算测定结果采用了标准曲线法及标准加入法,并对此两方法的精密度和准确度作了比较.结果表明:标准加入法具有更高的精密度,测定其相对标准偏差(n=6)为2.85%(溴离子)和1.86%(氯离子),经F检验法证明,特别对微量溴及氯的测定采用标准加入法更为有利.     

电位滴定法同时测定水体中碘溴氯

在弱酸性介质中,以双液接(外管盛4 mol LKNO_3)甘汞电极为参比电极、P_(AB)电极为指示电极、用硝酸银连续电位滴定碘、溴、氯离子,其精密度与共存的碘、溴含量密切相关。在1mol L硝酸中滴定,不仅有较大的电位突跃,而且不同量的碘与500μg溴共存时,不影响彼此的测定硫酸钾的存在可使溴的滴定终点更趋敏锐,且dE dv峰值均提高1倍以上,峰尾的滞留现象也显著消失在1mol L硝酸—2×10~2mol L硫酸钾介质中进行测定,下列共存离子(以mg计)SO_4~(2-)(100)、Fe~(3(?))(20)、Fe~(2+)、(20)、     

电生溴库仑滴定法直接测定渣油中硫醚硫的研究

本文提出了在甲苯－冰乙酸－乙醇－ＮａＢｒ电解液中电生溴库仑滴定电位法指示终点直接测定渣油中硫醚硫的新方法。该电解液对渣油样溶解性能好，终点电位突跃大，结果准确。     

氧瓶燃烧-电位滴定法测定溴系阻燃剂中的溴

随着全球安全环保意识的日益加强,人们对防火安全及制品阻燃的要求越来越高.目前国内塑料改性用阻燃剂近80%为含溴阻燃剂,包括脂肪族、脂环族、芳香族及芳香-脂肪族的含溴化合物,其中以十溴二苯醚、十溴联苯、十溴二苯乙烷等为代表的阻燃剂得到广泛应用.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。