分光光度法测定粮食中的硅

测定盐水样品及煤灰中的微量硅已有报道,但测定粮食中的微量硅尚未见到。文献中样品前处理要用到银坩埚,本文用镍坩埚代替银坩埚,结果表明,其间无显著性差异。     

分光光度法测定三苯基膦中的氯化物

本文研究了三苯基膦中氯化物含量的测定方法。试样用二甲苯溶解,以氢氧化钠溶液将其有机氯转化为无机氯离子,经萃取分离干扰离子后,用硫氰酸盐比色法测其总氯量。本法摩尔吸光系数3.0×10~3,准确度RSD％为6.74％,在0～100ppm氯含量范围内得到满意结果。     

分光光度法测定烟草中的硫

研究了在甘油－乙醇介质中用，分光光度法测定烟草中硫含量的方法，该法可应用于各种烟草样品分析，具有简单、快捷、实用等优点，硫含量在0－500ug/25ml范围内符合比耳定律，结果令人满意。     

分光光度法测定硅酸盐中的镁

2-(4-氯-2-膦酸基苯偶氮)-1,8-二羟基-3,6-萘二磺酸,即偶氮氯膦I(CPA-I)与Uo~(2 )、Ca~(2 )、Mg~(2 )、Cu~(2 )、Th~(4 )、Zr~(4 )等生成水溶性兰紫或兰色络合物。在PH=10的硼砂-氢氧化钠缓冲溶液中,CPA-I与Mg~(2 )络合显色快而稳定,是Mm~(2 )的良好显色剂。在0～0.4μg/mL浓度范围内,符合比耳定律。本方法测定结果准确可靠,可用于水泥、生料、熟料、石灰石、粘土等硅酸盐矿物中镁的测定。     

分光光度法测定硅酸盐中的镁

2—(4—氯—2—膦酸基苯偶氮)—1、8—二羟基—3、6—萘二磺酸,即偶氮氯膦Ⅰ(CPA—Ⅰ)与Uo~(2 )、Ca~(2 )、Mg~(2 )、Cu~(2 )、Th~(4 )、Zr~(4 )等生成水溶性兰紫或兰色络合物,在PH=10的硼砂—氢氧化钠缓冲溶液中,CPA—Ⅰ与Mg~(2 )络合显色快而稳定,是Mg~(2 )的良好显色剂。在0～0.4ug/ml浓度范围内,符合比耳定律。本方法可用于水泥生料、熟料、石灰石、     

分光光度法测定工业氯化铵中的硫酸盐含量

介绍了一种用721分光光度计在450mn波长下准确测定工业氯化铵中微量硫酸盐含量的方法，通过一段时间成品式样分析检验，验证了该方法的可靠性。     

导数分光光度法对痕量苯酚的测定

本文介绍了和导数分光光度法定量分析痕量苯酚的方法,本法操作简便快速、结果准确。测试结果证明;导数分光光度法对痕量组分的测定是十分有效的。     

分光光度法测定海带中的碘

讨论了用碘 -淀粉体系分光光度法测定海带中微量碘含量的方法。本实验以 Na NO2 作为氧化剂 ,使用淀粉作为显色剂 ,测得吸光度与含碘溶液浓度成线性关系 ,可检测范围为 0 .4～ 7μg· m L- 1 ,回收率为 85 %～12 0 % ,摩尔吸光系数为ε=1.2 6× 10 4 L· m ol- 1 · cm- 1 。该法具有准确度高 ,重现性好 ,简便快速的特点 ,是测定海藻中微量碘的一种较理想的方法     

分光光度法测定水中微量甲醇

介绍采用高锰酸钾氧化一乙酰丙酮分光光度法测定水溶液中微量甲醇的方法。     

Synthesis of N-vinyl caprolactam

The synthesis of N-vinyl caprolactam (NVCL), with acetylene as alkylene agent, was studied in a stirred reactor system. With potassium hydroxide (KOH) being used as catalyst and 18-crown-6 ether as cocatalyst, NVCL was synthesized by the reaction of acetylene with caprolactam (CL). Crude products were purified by vacuum distillation. The addition of 18-crown-6 ether accelerates the reaction rate of the nucleophilic addition much greatly. The initial explanation suggests that the hole radius of 18-crown-6 ether is close to the one of K⁺. A complex is formed between 18-crown-6 ether and K⁺ ion on the formed intermediate of potassium caprolactam, so the addition reaction between acetylene and caprolactam was accelerated greatly. In the stirred tank reactor (500 mL four flask bottle), the CL conversion is 30.5% and the product selectivity is up to 73.4%. The experimental data indicate that the product mixture is a non-ideal liquid mixture. A single process of distillation is difficult to obtain a high purity NVCL product. The combination of extraction and distillation is an ideal separation process for producing high purity NVCL.     

己内酰胺生产工艺及技术特点

介绍了己内酰胺主要工业化生产工艺,分析比较了其各自生产工艺、物耗能耗、环保、投资、市场应用等特点,对国内的己内酰胺行业前景进行了展望。     

利用离心萃取分离机处理己内酰胺废液

介绍了CTL离心萃取分离机结构及工作原理;讨论了CTL离心萃取分离机处理己内酰胺废液的工艺。结果表明:CTL萃取机能有效回收废液中的己内酰胺;CTL萃取机转速为800～1 000 r/min较适宜,废液中的己内酰胺回收率达60%以上,减少了污染物的排放。     

氯仿萃取回收己内酰胺的研究

以萃取回收甲苯法生产己内酰胺废液中的己内酰胺为目的,选择氯仿作萃取剂,进行了萃取回收己内酰胺的研究。考察了原料液的pH、萃取温度、萃取时间等因素对氯仿萃取己内酰胺过程的影响。结果表明,在酸性条件下该萃取过程分配比随pH的升高而增大,当pH=7时分配比最大;萃取过程为快速过程,20 min即可达到萃取平衡;水相中硫酸铵和1-磺酸基环己烷羧酸对萃取过程有盐析效应,使分配比增大;萃取过程受温度影响不大,焓变值ΔH=2.86 kJ/mol。实验确定了pH=7时己内酰胺在有机相与水相中的分配平衡关系,当有机相和水相体积比为1时,三级错流萃取的萃取率可达到98%以上。同时,进行了工业废水的萃取验证实验,结果表明,氯仿对废水中己内酰胺的萃取效果良好。     

国内外己内酰胺的供需现状及发展前景

分析了国内外己内酰胺的生产消费现状及发展前景,提出了发展我国己内酰胺生产的建议。     

己内酰胺加氢精制过程的影响因素分析

介绍了己内酰胺加氢精制的工艺流程,总结了国内某15万t/a固定床己内酰胺加氢精制装置的运行数据,探究了反应压力、温度和催化剂等对加氢精制效果的影响。结果表明:当反应压力在由0.3 MPa升高至0.5 MPa时,加氢出口高锰酸钾吸收值(PAN值)逐渐降低,继续提高反应压力,PAN值变化不明显;当反应温度在50℃~60℃时,PAN值基本可稳定在0.8~1.6,碱度在0.13 mmol/kg左右波动,可保证己内酰胺水溶液质量达标;经过加氢反应,己内酰胺水溶液吸光度小幅降低、碱度小幅升高,但不会影响成品己内酰胺的质量;固定床加氢催化剂寿命较短,其活性下降的主要原因是催化剂结块和表层被己内酰胺覆盖。     

A consecutive microreactor system for the synthesis of caprolactam with high selectivity

A microreactor system containing two consecutive microreactors and a stirred vessel was developed for the improvement of selectivity of caprolactam (CPL) synthesis. The first microreactor was used to conduct the reaction of cyclohexanecarboxylic acid and oleum, and 97% selectivity for the intermediate product, named mixed anhydride, was obtained. The mixed anhydride then quickly reacted with nitroso‐sulfuric acid in the second microreactor, and the reaction was completed in the vessel, where CPL selectivity reached 93.9%, a much higher value than that achieved either in a control experiment with a batch reactor or in industrial process. The advantage of microreactors is that they can provide high‐quality mixed anhydride and can mix it quickly with the nitroso‐sulfuric acid prior to reaction in the vessel reactor, which, from an engineering standpoint, gives better performance than the traditional syringe‐fed method that is common in chemical synthesis. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1959–1967, 2015     

基于Aspen plus的己内酰胺聚合过程模拟

应用化工流程模拟软件Aspen plus对己内酰胺水解聚合系统进行模拟。模拟计算了聚合物的相对分子质量及可萃取物含量随引发剂用量、进料流量、各聚合阶段温度的变化。结果表明:增加引发剂用量可以缩短聚合反应时间,但会降低聚合物的质量,选择引发剂质量分数0.013%为宜。随着进料流量的增加,聚合物相对分子质量减小且低于设计值,可萃取物含量增加且高于设计值;采用较低的聚合前段温度,可减少能耗,降低后段温度,可萃取物质量分数可降低至8%以下。     

环己酮肟气相重排制备己内酰胺工艺

报道了一种具有MFI结构的高硅亚微米级分子筛MS1,该分子筛制备工艺简便、成本低、环境友好。研究了MS1分子筛催化环己酮肟气相Beckmann重排制备己内酰胺的催化效果,考察了汽化温度、反应温度、环己酮肟浓度及质量空速（WHSV）等反应条件对环己酮肟气相Beckmann重排反应的影响;在优化的反应条件下环己酮肟转化率≥99.5%,己内酰胺选择性达95%,且催化剂稳定性较好;结果表明,MS1分子筛催化剂具有良好的工业化应用前景。     

新型己内酰胺萃取剂的筛选和评价

Mixed solvent of 1-octanol and cyclohexane with 60% （by mass） 1-octanol content was selected as a new extractant for caprolactam extraction. Compared with benzene or toluene, the new extractant has larger extraction capacity and much lower toxicity. Although the extraction capacity of the new extractant is smaller than that of pure 1-octanol, 1-octanol solubility of the new extractant in aqueous phase is much smaller. Because of its physical properties of lower density, lower viscosity, and higher interfacial tension, the new extractant performed much better phase separation ability than pure 1-octanol. The new extractant showed certain selectivity when dealing with lactam oil. The mixed solvent of 1-octanol and cyclohexane with 60% （by mass） 1-octanol content is a promising extractant for caprolactam extraction.