乙炔中磷化氢测定方法的改进

乙炔中磷化氢测定的仲裁法采用比色法，用氯化亚锡甘油溶液替代氯化亚锡盐酸溶液后，延长了氯化亚锡溶液的保存期限，使乙炔中磷化氢的测定更加方便。     

测定乙炔中磷化氢含量用饱和溴水的选择

通过对乙炔中磷化氢含量测定时所用氧化剂饱和溴水的验证，确定了测定磷化氢含量较适宜的药品。     

气相色谱法测定乙炔中杂质含量

本文利用气相色谱法,采用脉冲式火焰光度检测器(PFPD)对乙炔中磷化氢、硫化氢进行定量测定。通过改变PFPD的参数,确定最佳工作条件,使乙炔中硫化氢、磷化氢的测定更加准确、便捷。     

原料电石中硫含量测定的分析研究

电石产粗乙炔气中硫化氢、磷化氢等气体的存在,对化工反应过程中的触媒都有较大的毒害作用,控制乙炔气中的硫化物含量,对生产稳定和原料消耗都有极其重要的作用。本文从传统湿法乙炔技术和干法乙炔技术硫含量测定的几种方法进行分析对比,总结出了干法乙炔技术中硫含量测定的方法,具有很强的适用性和推广价值。     

快速分析硫化氢、磷化氢的检测管法——用于电石国家标准

电石、乙炔等化工产品中硫化氢和磷化氢含量的测定,我国大都采用化学法。由于化学法测定硫化氢、磷化氢的方法烦琐,分析时间长,要求分析人员操作水平高,否则将造成较大的分析误差。致使有的产品标准中虽订有此两项指标和检测方法,但都没能执行。所以化学法测定硫化氢和磷化氢,很难满足现代化工生产和使用的需要。     

乙炔气中硫磷含量的测定

按照国标的方法建立了用电石制取乙炔气的实验室装置,并用比色法测定了乙炔气中的硫化氢、磷化氢含量,用容量法测定了电石反应生成的无机硫含量。测定方法的建立有助于电石中硫磷含量的准备确定。     

用检测管测定乙炔中微量的硫化氢和磷化氢

<正> 近年来,应用检测管测定微量硫化氢和磷化氢的方法已引起了各国分析工作者普遍兴趣。用容量法分析硫化氢和磷化氢,手续繁复,时间长,需数小时才能进行一次,而仪器分析则受条件限制。如采用检测管,成本低,无需电源、热源,方法简便、快速,准确度和精密度也符合微量分析要求。电石及乙炔气中微量硫化氢和磷化氢的检测管测定     

气相色谱法测定乙炔气中硫磷化合物含量

介绍一种气相色谱法测定乙炔气中微量硫磷化合物含量的方法。采用火焰光度检测器,通过光电倍增管进行信号放大,并在其出口处分别设置有硫滤光片和磷滤光片,用于完成乙炔气中硫化氢与磷化氢的检测。该方法准确度高、重现性好、分析速度快,能够表征乙炔气中微量硫磷化合物的基本情况。     

矿石中钼还原光度法的改进

以氯化亚锡还原光度法测定矿石中钼时,氯化亚锡溶液需要现用现配,多余试剂倒掉,不仅造成试剂的浪费,同时也污染环境。本法采用40%丙三醇作为氯化亚锡还原剂的介质,使氯化亚锡储备液的使用时间不受限制,测定国家标准物质与标准方法无显著差异,其准确度和精密度能达到测量要求。     

钼蓝分光光度法测定污水中总磷的研究

对钼锑抗分光光度法和氯化亚锡分光光度法测定污水中总磷的结果进行了对比，探讨了氯离子浓度对两种测定方法的影响，验证了新的抗坏血酸溶液配制方法。结果表明，钼锑抗分光光度法和氯化亚锡分光光度法测定污水中总磷没有显著差异(P>0.05),但氯化亚锡分光光度法易受氯离子的干扰，钼锑抗分光光度法能更好地满足检测工作的需要。抗坏血酸溶液中加入适量的EDTA和冰乙酸，放置60 d时吸光值仅下降1.61%,说明使用该方法配制的抗坏血酸溶液至少可稳定保存60 d;使用保存了60 d的抗坏血酸溶液测定污水样品，测定结果的准确度、精密度、重复性等均满足生产需要。     

返滴定法测定氯化钾无氰镀镉溶液中氯化镉

制定了氯化钾无氰镀镉溶液中氯化镉的返滴定分析方法,在强酸性和加热条件下用过硫酸铵氧化镀液中的配位剂,使镉离子从配合物中释放出来。用氟化钠掩蔽Al³⁺和Sn⁴⁺杂质,用三乙醇胺掩蔽Fe³⁺杂质。加入过量的EDTA标准溶液配位Cd²⁺,在pH≈9.3的条件下,以铬黑T作指示剂,用硫酸锌标准溶液返滴定EDTA,用差减法计算镀液中氯化镉的质量浓度。结果表明,测定结果的相对平均偏差为0.19%,回收率为98.03%。     

化学沉积法制备功能性化学镀锡层的研究

在紫铜表面制备了功能性化学镀锡层。用扫描电镜观察了化学镀锡层的表面形貌,用X射线衍射仪分析了化学镀锡层的物相,并用电化学工作站对化学镀锡层的耐蚀性进行了测试。结果表明:化学镀锡层表面比较致密,呈不规则的柱状结构;化学镀锡层的XRD图谱中出现了六个明显的锡衍射峰;化学镀锡层能为紫铜提供有效的保护,提高紫铜在质量分数为3.5%的氯化钠溶液中的耐蚀性。     

碘酸钾滴定法测定阳极泥中锡含量

主要对碘酸钾滴定法测定阳极泥中锡的含量的操作条件进行了试验。通过对试样的分解、铁粉、铝粒及淀粉溶液的用量进行了试验研究,并对其中影响测定锡的杂质元素进行了分离。用代表样加锡标准考查方法的准确度及精密度,样品加标回收率在99.2%～100.2%之间,精密度和准确度较好。该测定方法终点易观察,测定结果稳定准确,适用于测定阳极泥中10%以上的锡含量。     

Optimization of Ti/SnO<Subscript>2</Subscript>–Sb<Subscript>2</Subscript>O<Subscript>5</Subscript> anode preparation for electrochemical oxidation of organic contaminants in water and wastewater

The preparation of antimony-doped tin oxide anodes on a titanium substrate (Ti/SnO₂–Sb₂O₅ anodes) by dipping in a solution of tin chloride and antimony chloride and annealing at high temperatures was optimized for the potential applications of drinking water disinfection, wastewater effluent disinfection, and industrial waste stream treatment. The effectiveness of Ti/SnO₂–Sb₂O₅ anodes prepared under different conditions was evaluated by using hexanol as a probe molecule to measure the extent of oxidative reactions, and anode performance was monitored by cyclic voltammetry. A large factorial matrix consisting of tin chloride concentration × antimony chloride concentration × annealing temperature was first evaluated, and the optimum conditions were found to be 20% tin chloride and 1% antimony chloride in the dip solution and an annealing temperature of 500°C. Further investigation showed that the rate of withdrawal from the dip solution, the number of coatings of the dip solution, and the addition of oxygen during annealing did not significantly affect anode performance. Under optimum preparation conditions, Ti/SnO₂–Sb₂O₅ anodes showed no loss of performance over 1,280 cycles of cyclic voltammetry, suggesting that their performance can be sustained over long periods of use. The result of this research is a simple preparation method for effective and long-lived Ti/SnO₂–Sb₂O₅ anodes; this method could be easily adopted by a utility for pilot- or full-scale disinfection of water and wastewater and the treatment of industrial waste streams.     

The mechanism of stabilization of poly(vinyl chloride). II. Cleavage of organotin sulfur compounds by anhydrous hydrogen chloride

A number of organotin compounds of the type R_nSn Y_4–n, where R = alkyl or aryl; Y = alkylthio, arylthio or carbothiolate; and n = 1, 2, 3 have been prepared and treated with hydrogen chloride at 180°C in o-dichlorobenzene solution. The organotin compounds were also tested at 190°C as thermal stabilizers for PVC. Cleavage of tin–carbon bonds by hydrogen chloride was demonstrated in some cases by analysis of the organotin–hydrogen chloride reaction products. The formation of monoalkyl(aryl)tin chlorides or stannic chloride, or both, in the model system was shown to correspond to a catastrophic mode of degradation in the polymer. The use of stabilizers with fewer than two alkyl or aryl groups on tin also gave this mode of degradation.     

氯气浸出硫渣制备四氯化锡

四氯化锡的生产是用精锡与氯气反应得到的。为了降低工业四氯化锡的生产成本,采用硫渣（粗锡精炼产出的一种废渣）与氯气反应,制备四氯化锡。研究了氯气浸出反应温度,反应时间,液固比,搅拌速度等因素对硫渣中锡浸出率的影响。实验结果表明,氯气能够与硫渣中的锡反应,生成四氯化锡,硫渣中锡的浸出率可以达到90%以上。最佳浸出条件：四氯化锡与硫渣的初始液固质量比为2∶1,反应温度为80～90 ℃,反应时间为6 h,搅拌速度为100 r/min。浸出液经过精馏,脱除三氯化砷、三氯化锑等杂质,实验产出的四氯化锡产品的质量达到用精锡生产的四氯化锡产品的质量标准要求。     

Effects of raw materials and preparation methods of catalysts on the selective hydrogenation of ethyl phenylacetate

A ruthenium/tin/alumina catalyst was found to hydrogenate ethyl phenylacetate to 2-phenylethanol selectively with a high yield. The optimum atomic ratio of ruthenium to tin was 1∶2, and the optimum metal content was about 5 and 11.75 wt% for ruthenium and tin, respectively. The raw materials of the catalyst had a significant effect on the conversion and selectivity in the catalytic hydrogenation. Chloride had a negative effect on catalytic activity. Washing the catalysts, which were prepared from chloride materials, with distilled water or alkali solution had a positive effect upon catalyst activity. The catalyst prepared from chloride-free raw materials performed the best, and the impregnation catalyst has a higher yield than the solgel catalyst, suggesting that impregnation is a suitable procedure for this reaction.     

Some aspects of the behaviour of inorganic constituents of two Australian brown coals during hydroliquefaction

An examination has been made of the changes taking place in the mineral and other inorganic matter contained in two Australian brown coals as a result of hydroliquefaction of the coal in tetralin and hydrogen at 25 MPa and 395 °C. Iron sulphides were found to be reduced to pyrrhotite, whereas iron carboxylates decomposed mainly to magnetite. Calcium carboxylates formed predominantly vaterite, whereas when coals were subjected to low-temperature ashing calcite was formed. Amorphous tin oxide, precipitated onto the coal by hydrolysis of stannous chloride solution, was largely reduced during hydrogenation to liquid tin, some of which reacted with hydrogen sulphide to form herzenbergite.     

电白槽液中磷酸氢二钠和碳酸纳的分析

介绍了电白槽液中磷酸氢二钠和碳酸钠的分析方法。用磷钼蓝光度法测定电白槽液中磷酸氢二纳的质量浓度,用过硫酸铵破坏氰化物,消除其对测定的干扰。在硫酸介质中,以抗坏血酸作还原剂,硝酸铋作催化剂,使磷酸与钼酸钠生成杂多酸蓝色络合物,以显色剂作参比液,在波长660nm处测定吸光度。试验表明,镀液中的铜离子和其它组份对测定无影响,本法相对平均偏差为1.3%,回收率为97.3%-103%。用硝酸银掩蔽氰化钠,以酚酞作指示剂,用盐酸滴定法直接测定电白槽液中碳酸钠的质量浓度。试验表明,镀液中的Na2[Sn(CN)4]、Na2[Cu(CN)2]和磷酸氢二钠对测定无干扰,本法相对平均偏差为0.54%,回收率为101%。而用传统的铜锡合金镀液分析方法,电白槽中的磷酸氢二钠严重影响碳酸钠的测定。     

工业氯化钡质量的快速测定

介绍利用硫酸银标准溶液滴定氯化钡溶液的快速测定工业氯化钡含量的新方法。