废碱液回收试验中甲酸钠的分析

采用高氯酸非水滴定法分析废碱液中的甲酸钠,代替了误差较大的高锰酸钾法。用高氯酸滴定样品中的甲酸钠和醋酸钠(氢氧化钠与冰醋酸反应生成的),用盐酸滴定样品中的氢氧化钠,方法的回收率为97%~104%。     

非水滴定法测定盐酸水苏碱的含量

建立了测定盐酸水苏碱含量的非水滴定法。以冰醋酸作溶媒,以0.2%结晶紫为指示剂,用0.1 mol/L标准高氯酸溶液进行滴定。平均回收率为98.74%,RSD为0.68%(n=6)。本方法简单、可靠、准确。     

Titration of cyclopropene esters with hydrogen bromide

Esters of the naturally occurring cyclopropene acids have heretofore been determined by titration with hydrogen bromide in glacial acetic acid. However, highly purified cyclopropenes had an apparent purity of only 83–86% by this method. The catalyzed addition of acetic acid during the titration has been shown to occur. Substituting toluene for the acetic acid not only gives the correct cyclopropene content, but also sharpens the end point of the titration. The new titration is performed at 70–75 C and 1,3-diphenylguanidine, which is soluble in toluene, should be used as a primary standard. The indicator solution is 0.03% crystal violet in butyric acid. Mono- and diglycerides and oxidized fatty compounds must be removed before titration. Oxirane oxygen can be determined by the new procedure, probably with an accuracy greater than that possible with hydrogen bromide in glacial acetic acid. Presented at the 41st Fall Meeting of the American Oil Chemists’ Society, Chicago, Ill., October 15–18, 1967.     

Determination of hexamethylene tetramine in thermosetting moulding compounds

Hexamethylene tetramine (hexamine) in phenol-formaldehyde and urea-formaldehyde moulding compounds can be determined by non-aqueous titration in acetic acid solution with perchloric acid. Phenolic compounds may be dissolved directly in glacial acetic acid and the hexamine may be titrated. However, hexamine must first be extracted from dry urea-formaldehyde samples with chloroform before titration as the resin interferes with the titration. Nuclear magnetic resonance spectroscopy may also be used to determine the hexamine content of the extracted solution.     

The assay of hydrazine mononitrate as a base in acetic acid

Hydrazine mononitrate has been determined as a base by non-aqueous titration in glacial acetic acid. The titrant was 0.05 N perchloric acid in glacial acetic acid which must be prepared without acetic anhydride. Small amounts of water increase the solubility of hydrazine nitrate, but reduce the sensitivity of the method.     

固体超强酸S2O2-8/TiO2的溶胶-凝胶法制备与表征

以钛酸四丁酯、无水乙醇、冰醋酸和过硫酸铵等为原料，采用溶胶-凝胶法制得前驱体，再经500 ℃焙烧得到固体超强酸S₂O^2-₈/TiO₂催化剂，采用XRD、IR和Hammett指示剂法对其进行表征，结果显示催化剂样品为超强酸，酸强度H₀＜-14.52。以乙酸乙酯合成反应为模型反应考察其催化活性和稳定性。结果表明，催化剂有较高的活性，当反应条件为醇酸体积比1.5∶1、催化剂0.6 g和反应时间3.0 h时，乙酸转化率可达73.09%（不加分水器）。催化剂稳定性较好，活性下降缓慢，可在无需任何再生的条件下重复使用。重复使用5次后，乙酸转化率仍然达55.13%。     

非水滴定法测定乙氧基喹含量的研究

研究了用高氯酸标准溶液对乙氧基喹含量的非水滴定 ,具体方法为 :精确称乙氧基喹0 2 g ,加 5 0mL冰乙酸、1mL乙酸酐、加 2滴结晶紫指示剂 ,用高氯酸标准溶液滴定至溶液由蓝紫色变为绿色。电位滴定法与指示剂法的测定结果一致 ,极差 0 34%。此方法容易操作 ,滴定终点清晰 ,准确可靠 ,重复性好。     

应用电位滴定法测定石油产品的溴值

以冰醋酸、三氯甲烷、甲醇和1:5的硫酸(体积比为714:134:134:18)作为滴定溶剂,采用电位滴定法测定石油产品的溴值,并与指示剂滴定法进行对比。结果表明,该方法相对误差小,操作简单,结果准确可靠。尤其使用于深色石油产品。     

对氯苯氧乙酸钾的含量测定方法研究

介绍了用冰醋酸作溶剂,以高氯酸作滴定剂对对氯苯氧乙酸钾的含量进行测定的半微量非水滴定法。     

无水乙酸钠含量的快速测定

研究了对无水乙酸钠含量的快速测定。具体方法为:精确称取无水乙酸钠0.2g,加30mL冰乙酸、1mL乙酸酐、2滴结晶紫指示剂,用高氯酸标准溶液病定至溶液由蓝紫色变为绿色。电位滴定法与指示剂法的测定结果一致,极差0.3％。此方法容易操作、滴定终点清晰、准确可靠、重复性好。     

Hydrogen bromide titration for soaps in fat products

Since none of the existing methods for determining soaps in fat products have been found to be entirely satisfactory, a method has been devised for the determination of alkali metal soaps by direct titration with Durbetaki reagent (hydrogen bromide dissolved in glacial acetic acid). When the titration was conducted at room temperature in acetic acid-benzene solution with crystal violet as indicator, soaps of potassium, sodium and lithium could be determined accurately in anhydrous oils, monoglycerides, and sucrose esters. The presence of alcohols, glycerol and sucrose did not interfere in the direct titration. However, oxidized oils, epoxides, and cyclopropenoid acids, which are known to consume hydrogen bromide, did interfere. Products containing the interfering substances could be analyzed by a modified procedure in which the alkali metal cations were extracted from a mixture of amyl acetate andn-butanol (1:3) into an aqueous solution of acetic acid, and titrated as the acetates.     

非水滴定法定量测定己二胺盐酸盐

建立了测定己二胺盐酸盐含量的非水滴定法。以高纯度冰醋酸为溶剂,0.2%结晶紫为指示剂,用0.1 mol/L高氯酸标准溶液滴定至己二胺盐酸盐溶液由紫色变为蓝色。分别采用电位滴定与指示剂两种指示终点的方法。结果表明:2种指示终点的方法无显著差异,相对平均偏差为0.047%～0.070%。该方法操作简单、准确可靠、滴定终点突跃明显,重现性好。     

高氯酸电位滴定法测定对氨基苯甲酸正丁酯的含量

研究了用高氯酸标准溶液对对氨基苯甲酸正丁酯含量的非水滴定,具体方法为:精确称量对氨基苯甲酸正丁酯,用约25 mL的冰醋酸微热溶解。用配制好的高氯酸进行电位滴定,应用一阶导数法得出滴定结果。此方法容易操作,回收率在98.5%~103.9%之间。     

一种水溶性烷基咪唑啉季铵盐润滑剂的合成

以硬脂酸、四乙烯五胺为原料,采用阶梯升温自由出水法合成了烷基咪唑啉,然后采用冰醋酸进行季铵化反应,生成烷基咪唑啉季铵盐。确定了烷基咪唑啉季铵盐的最佳合成条件为:硬脂酸、四乙烯五胺、冰醋酸的摩尔比为1.1:1:2.5,酰胺化温度为160℃,酰胺化时间3h,环化温度190℃,环化时间1.5h。经过红外分析判断,合成产物为烷基咪唑啉季铵盐,应用于玻璃纤维生产中,能满足玻璃纤维的性能要求。     

Analysis of soaps with hydrogen bromide in glacial acetic acid

Alkali metal carboxylic acid salts of long-chain fatty acids and of α-sulfo fatty acids are determined by titration with hydrogen bromide in glacial acetic acid medium. Crystal violet is used as indicator. A laboratory of the E. Utiliz. Res. & Dev. Div., ARS, U.S.D.A.     

过硫酸铵法催化2-甲基萘氧化合成2-甲萘醌工艺研究

以2-甲基萘为原料,乙酸为溶剂,过氧化氢作为氧化剂,在过硫酸铵的催化作用下合成2-甲萘醌,采用高效液相色谱法检测产品纯度。结果表明,在2-甲基萘与乙酸物质的量比为1:15、过氧化氢与2-甲基萘物质的量比为1:11.5时,加入过硫酸铵为2-甲基萘质量的2%,于75 ℃条件下反应4 h,2-甲基萘转化率最大为56.4%,2-甲萘醌收率最高达36.5%。     

球形聚苯并噁嗪树脂酸催化性能研究

苯并噁嗪预聚体在甲基硅油中经反相悬浮固化法得到球形聚苯并噁嗪树脂,再经磺化反应后制得聚苯并噁嗪树脂酸。通过催化冰醋酸与乙醇的酯化反应来考察该树脂酸的催化活性。结果表明:当V(甲基硅油)∶V(苯并噁嗪预聚体)=100∶6.0、固化温度为200℃左右时,可得到球形聚苯并噁嗪树脂。当磺化温度为45℃、反应时间为3 h和w(催化剂)=4.8%(相对于冰醋酸而言)时,则冰醋酸的转化率为73%;催化剂连续重复使用3次后,其转化率仍超过60%;经磺化再生后的催化剂,其催化活性基本上能完全恢复。     

甲烷液相氧化酯化过程中非水醋酸混合溶液酸度测定

为从理论上分析非水醋酸混合溶液酸度对甲烷液相氧化酯化反应的影响,建立了 Hammett 指示剂-紫外可见光分光光谱法测定醋酸混合溶液酸度的方法,并考察了相同浓度下不同酸性助剂的醋酸混合溶液对甲烷液相氧化酯化反应影响.结果表明,室温下,以三氯甲烷、甲基紫分别为溶剂和指示剂,可以表征醋酸混合溶液的酸度.改变醋酸混合溶液的中酸性助剂的种类和比例,可以有效调控醋酸混合溶液的酸度,而且醋酸混合溶液的酸度与甲烷液相氧化酯化反应有一定关联.     

络合滴定法测定钛熔块釉中的铅

本文研究用EDTA络合滴定法，准确、快速测定陶瓷用的钛熔块釉中的铅。试样经氢氟酸—硫酸分解，生成硫酸铅沉淀，用乳酸掩蔽钛的干扰。其沉淀用乙酸—乙酸铵溶解，以EDTA标准溶液直接滴定铅。     

Synthesis and optical properties of novel, thermally stable phenanthrolines bearing an arylthienyl-imidazo conjugation pathway

Six new hyperpolarizable chromophores based on functionalized arylthiophene donors and an imidazo-phenanthroline acceptor moiety have been designed and synthesized for the first time in good to excellent yields by condensation of 5,6-phenantroline-dione with formyl-arylthiophene derivatives in the presence of ammonium acetate in glacial acetic acid. The thermal stability, solvatochromic and nonlinear optical properties of these compounds were evaluated.