EDTA滴定法测定钼铁及其合金中钼

关于钼铁中主量元素钼的分析[1] ,现有的 8 羟基喹啉重量法[2 ] ,准确度虽高 ,但操作周期冗长 ;而比色法的灵敏度远达不到分析要求 ,且相对误差很大 ,因此 ,两者均不能适应厂矿快速、准确的分析要求。ＥＤＴＡ滴定法测定钼铁及其合金中的钼 ,对于10 %～ 60 %的钼含量的分析 ,做到了快速、准确 ,相对误差小于 1%。1　试验部分1.1　主要试剂ＥＤＴＡ溶液 :0 .0 1ｍｏｌ·Ｌ- 1,称取ＥＤＴＡ3 72 2 4 ｇ ,溶解于水中 ,移入 1Ｌ容量瓶中 ,以水稀释至刻度 ,摇匀。硝酸铋溶液 :0 .0 1ｍｏｌ·Ｌ- 1,称取Ｂｉ(ＮＯ3) 3·5Ｈ2 Ｏ 4 .85 0 7ｇ于 2 5 …     

关于配位滴定测定水的总硬度终点返红问题的讨论

ＥＤＴＡ滴定法测定水的总硬度时 ,常以 0 .1ｍｏｌ·Ｌ-1氨 氯化铵缓冲液调节溶液ｐＨ为 1 0 ,以络黑Ｔ为指示剂 ,用 0 .0 1ｍｏｌ·Ｌ-1ＥＤＴＡ滴定。此方法使用过程中经常出现终点返红问题。本文对此进行了试验。1　试验部分1 .1　主要仪器与试剂ＣＯ2 发生器 (自制 )氨 氯化铵缓冲溶液 :0 .1ｍｏｌ·Ｌ-1所用试剂均为分析纯以上1 .2　试验方法取自来水样 1 0 0 .0ｍｌ,以 0 .1ｍｏｌ·Ｌ-1氨 氯化铵缓冲液调节其 ｐＨ为 1 0 ,加络黑Ｔ指示剂 (与ＮａＣｌ配比为 1∶1 0 0 )少许 ,以 0 .0 1 0 0 0ｍｏｌ·Ｌ-1ＥＤＴＡ标准溶液滴定至终点…     

5-Br-PADAP光度法测定锰矿中微量钴

5 Ｂｒ ＰＡＤＡＰ作为显色剂 ,已被广泛用于测定许多金属元素。本文将其用于锰矿中微量钴的测定 ,获得满意结果。1　试验方法取 0～ 10 μｇ钴标准于 5 0ｍｌ容量瓶 ,加入0 0 5ｍｏｌ·Ｌ-1氨三乙酸 5ｍｌ,10 0ｇ·Ｌ-1ＮＨ4 Ｆ溶液 2ｍｌ,以水稀至约 30ｍｌ ,加入 7.5× 10 -4 ｍｏｌ·Ｌ-15 Ｂｒ ＰＡＤＡＰ溶液 4ｍｌ ,摇匀 ,放置 2 0ｍｉｎ ,在摇动下加入硫酸 (1+2 ) 10ｍｌ,以水稀释至刻度 ,用 2ｃｍ比收稿日期 :2 0 0 1 0 4 2 9色皿 ,5 80ｎｍ波长处 ,在 72 1Ａ分光光度计上测其吸光度。2　样品分析称取样品 0 .2 0 0 0ｇ于 2 0 0…     

催化示波极谱法测定电解铅中痕量硒碲

本文用催化示波极谱法 ,在亚硫酸钠 氯化铵 酒石酸钠 ＥＤＴＡ 氨水的混合底液中 ,以高碘酸钾与硝酸催化硒波 ,以高碘酸钾催化碲波 ,可以得到硒与碲的两个良好的催化波 ,波峰电位硒约 - 0 .92Ｖ ;碲约 - 1.0 5Ｖ ,互不干扰 ,可在一份溶液中同时测定0 0 0 0 0 5 %左右的硒碲 ,浓度在 0～ 1.0 μｇ/ 10ｍｌ之间保持线性关系。1　试验部分1.1　试剂与仪器亚硫酸钠溶液 :2 0 0ｇ·Ｌ- 1混合底液 :称取氯化铵 10ｇ ,酒石酸钠 8ｇ ,ＥＤＴＡ二钠 0 .4ｇ ,加水 70ｍｌ,氨水 30ｍｌ,移入 10 0ｍｌ容量瓶中 ,混匀 (冬天应先微热溶解 )。高碘酸钾…     

吸光光度法测定空气中一甲胺的改进

车间空气中一甲胺的测定 ,目前推荐的方法仅为对硝基苯胺重氮盐比色法[1] ,作者在工作中发现 ,该法中对硝基苯胺重氮盐溶液的加入量对其影响很大 ,为此 ,进行了一系列探讨并加以改进。1　试验部分1.1　仪器与试剂72 1型分光光度计吸收液 :0 .0 1ｍｏｌ·Ｌ- 1盐酸溶液缓冲液 :80ｍｌ蒸馏水内溶解 4 .0 8ｇ磷酸二氢钾、1.6ｇ硼砂 ,再加入 5 .0ｍｏｌ·Ｌ- 1氢氧化钠溶液 6.35ｍｌ,用水稀释至 10 0ｍｌ亚硝酸钠溶液 :5 .0 ｇ·Ｌ- 1对硝基苯胺盐酸溶液 :1.0 ｇ·Ｌ- 1,将 0 .1ｇ对硝基苯胺溶于 1.0ｍｏｌ·Ｌ- 1盐酸 10 0ｍｌ中。对硝基苯胺重…     

硅钼蓝光度法测定五氧化二钒中微量硅

采用氢氧化钠对试样进行前处理 ,在硝酸 0 .0 8～ 0 .4 0ｍｏｌ·Ｌ- 1酸度下 ,硅与钼酸铵形成硅钼酸络离子 ,在硫酸 0 .8～ 1.6ｍｏｌ·Ｌ- 1酸度下 ,被还原生成硅钼蓝 ,借此进行光度测定[1] ,硅量在 10～ 10 0 μｇ/5 0ｍｌ范围内遵守比耳定律。1　试验部分1.1　仪器与试剂72 2光栅分光光度计硅标准溶液 :10 μｇ·ｍｌ- 1五氧化二钒标准溶液 :2 .5ｍｇ·ｍｌ- 1,称取五氧化二钒 (99.99%) 0 .2 5 0 0 ｇ置于 30 0ｍｌ聚四氟乙烯烧杯中 ,加入 10 0ｇ·Ｌ- 1ＮａＯＨ溶液 10ｍｌ,低温加热溶解 ,取下 ,加入数滴酚酞 ,用ＨＮＯ3 (1+ 1)调至无…     

火焰原子吸收光谱法测定粗杂铜中锑

在铜冶炼的全过程中都要对锑进行分析。方法主要有比色法、滴定法、共沉淀分离原子吸收光谱法 ,但分析方法都较繁琐[1] 。本法试验在锑不水解的情况下 ,不分离基体铜 ,直接用原子吸收光谱法测定粗杂铜中锑。并对样品分解、元素干扰作了试验 ,对方法的准确度、精密度作了考查 ,取得满意结果。1　试验部分1.1　主要试剂与仪器酒石酸溶液 :10 0 ｇ·Ｌ- 1锑标准溶液 :5 0 0 μｇ·ｍｌ- 1,称取金属锑(99 99%以上 ) 0 .5 0 0 0 ｇ于 2 0 0ｍｌ烧杯中 ,加酒石酸 5 ｇ ,硝酸 30ｍｌ,低温溶解完全 ,赶尽氮的氧化物 ,冷却后用水移入 1Ｌ容量瓶中定容…     

吸光光度法测定水中微量阴离子表面活性剂

目前用于测定水中阴离子表面活性剂的国标方法是亚甲蓝吸光光度法。该法不仅操作繁琐、准确度差、易受各种共存物的影响 ,而且灵敏度低 ,最低检测浓度仅为 0 .0 5ｍｇ·Ｌ- 1,难以满足残留量的测定要求。本文在前人工作的基础上运用Ｃｏ ＰＡＤＡＰ方法进行水中微量阴离子表面活性剂试验 ,最低检测浓度为 0 0 2ｍｇ·Ｌ- 1,干扰物质少 ,准确度和重现良好。1　试验部分1.1　主要仪器与试剂72 1型分光光度计Ｃｏ ＰＡＤＡＰ的合成 :称取 5 Ｂｒ ＰＡＤＡＰ 1.0 0 ｇ溶于 30ｍｌ盐酸 (2ｍｏｌ·Ｌ- 1)中 ,加入 50 ｇ·Ｌ- 1ＣｏＣｌ2·6Ｈ2 Ｏ…     

铁矿中全铁、二氧化硅和氧化钙的测定

铁矿的质量检查和入炉铁矿全铁、二氧化硅和氧化钙的测定 ,是中小型铁厂化验室相当繁重的一项日常工作 ,表现为试样数量多 ,测试频率高 ,同时要求较快地报出结果。采用既经济又快速实用的分析方法 ,对指导高炉生产有着十分重要的意义。1　试验部分1.1　主要仪器与试剂72 1ＳＸ分光光度计钨酸钠溶液 :5 0ｇ·Ｌ- 1,称取Ｎａ2 ＷＯ4 ·2Ｈ2 Ｏ 5ｇ溶于 5 0ｍｌ水中 ,加磷酸 10ｍｌ,用水稀释至 10 0ｍｌ ,摇匀。三氯化钛溶液 :将 15 0～ 2 0 0ｇ·Ｌ- 1三氯化钛用盐酸 (1+ 1)稀释 3倍硫酸铜溶液 :2 0ｇ·Ｌ- 1硫 磷混酸 :Ｈ2 ＳＯ4 ∶Ｈ2 ＰＯ…     

偶氮氯膦Ⅰ光度法测定镁

测定铜矿中镁的方法不少[1] ,但均存在一些不足之处。本文采用光度法测定镁的显色剂为偶氮氯膦Ⅰ (ＣＰＡ Ⅰ ) ,于ｐＨ 10左右的硼砂 氢氧化钠缓冲液中显色 ,试验表明 ,方法的准确度和精密度能满足分析要求。1　试验部分1.1　主要仪器与试剂75 4型分光光度计镁标准溶液 :10 μｇ·ｍｌ-1,称取于 60 0℃灼烧 1ｈ后的高纯氧化镁 0 .10 0 0ｇ于烧杯中 ,加ＨＣｌ(1+ 1)10ｍｌ,盖表皿 ,低温溶解后 ,加水定容于 1Ｌ容量瓶中 ,吸取溶液 5 0ｍｌ,加水稀至 5 0 0ｍｌ容量瓶中。显色剂 :0 .30 0 0ｇ·Ｌ-10 .30 0ｇＣＰＡ Ⅰ溶于 1Ｌ水中氢氧化钠 …     

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。     

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.     

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.     

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.

     

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.     

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。