2.4—二氯苯甲醛合成

2.4—二氯苯甲醛在无线电行业被用作电镀光亮剂已初露峰芒。但目前国内尚未生产,部分试剂由国外进口,这不仅消耗外汇,更限制了2.4—二氯苯甲醛的推广应用。 2.4—二氯苯甲醛合成,系以2.4—二氯代苯亚甲基氯经水解,或以2.4—二氯代苯甲基氯与六次甲基四胺(乌洛托品)加热制得。     

XM-2.4L型密炼机控制系统

简要介绍了XM-2.4L型密炼机混炼过程中功率曲线的重要性以及密炼机的参数、结构、控制系统的组成、控制步骤以及改善混炼工艺的优化方法。采用XM-2.4L型密炼机控制系统可使混炼工艺保持最佳的状态，混炼胶质量均一，而且操作，控制和维修非常方便。     

气相色谱法测定2,4-滴的残留量

2.4-滴的化学名称为2.4-二氯苯氧乙酸。它是一种除草剂,也作为一种植物生长刺激剂使用。如在果芽的贮存中使用了加有2.4-滴的果芽涂料,就能对果芽起到良好的保鲜作用。为此必须鉴测2.4-滴在果芽中的残畄量,根据生产实际的需要,我们试验了测定2,4-滴残畄量的气相色谱法。此法具有灵敏度高的特点,2,4-滴的残畄量检出限度为0.05ppm。国外使用气相色谱法检出大气、土圵、水沅以及牧草中的2,4-滴的残畄量,开展了广泛的     

锅炉汽包三冲量DCS控制系统的设计

介绍了2.4亿Nm3/a焦炉煤气制液化天然气装置中锅炉汽包三冲量控制的DCS设计方案和测量仪表的选择。     

4,6-二(二苯基膦)吩嗪的合成工艺研究

以吩恶嗪为原料,经过叔丁基二甲基氯硅烷对氮原子进行保护,引入二苯基膦基,脱保护三步得到了4,6-二(二苯基膦)吩嗪,采用NMR和HRMS对各步中间体和目标化合物进行了表征。通过对各反应过程的优化,确定了最佳工艺。在第一步中以THF为溶剂,n(吩恶嗪)∶n(氢化钠)∶n(叔丁基二甲基氯硅烷)=1∶1.25∶1.5,反应温度75℃。第二步中以乙醚为溶剂,n(化合物II)∶n(n-BuLi)∶n(Ph2PCl)∶n(TMEDA)=1∶2.4:2.4∶2.4。最后在四丁基氟化铵的作用下经过24 h脱去保护基,以62%的总收率得到了4,6-二(二苯基膦)吩嗪。     

25%2·4D丁酯+20%辛酰碘苯腈乳油的液相色谱分析

论述了在同一液相色谱条件下测定2.4D丁酯+辛酰碘苯腈中的2.4-D丁酯、辛酰碘苯腈含量的方法。本方法采用反相色谱柱分离,三元混合流动相进行洗脱,紫外可变波长检测器进行检测,以外标法定量。     

焊接技术在回转窑窑头段节更换中的应用

1 φ2.4 m/φ2.8m×40m回转窑的技术参数与基本施工条件 1.1 几何参数 由图1所示,回转窑全长40 m,前段简体直径φ2.8 m,中部锥变径筒体φ2.8 m/φ2.4 m×3 m,后部简体直径φ2.4m,轮带下部筒体厚度δ=40mm,其余部分δ=20mm.     

2.4-二硝基甲苯的气相色谱分析

建立了以丙酮溶解试样,经OV-225石英毛细管柱分离的2.4-二硝基甲苯气相色谱分析方法.平均回收率为98.92%～104.69%,标准偏差(δ)为0.0020～0.0097,相对标准偏差(RSD)为0.0098%～2.58%,为工业品2.4-二硝基甲苯的质量控制提供了一个简便、准确、快速的分析方法.     

新型农药中间体2,4-二氯苯基戊酮中的间二氯苯气相色谱分析

研究了新型农药中间体2.4-二氯苯基戊酮中的间二氯苯气相色谱分离条件.以10%SE-30/Chromosorb W.AW.DMCS为同定相,氢离子火焰检测器检测.以苯甲酸甲酯作为内标物,采用内标定量分析法.测得2.4-二氯苯基戊酮中的问二氯苯的平均回收率为99.23%,相对标准偏差小于0.02%.     

油站不供油的防范措施

2001年,我公司新安装Φ2.4×10m、Φ2.4×7.5m、Φ2.2×11m球磨机各一台,在投产初期,由于润滑系统在设计上存在缺陷,再加上管理经验不足,导致4起烧瓦事故和一起未遂事故的发生。因     

化学专业绘图软件ISIS/Draw2.5在计算机辅助筛选牛蒡子苷元结合蛋白中的应用

ISIS/Draw2.5是一款功能强大的化学专业绘图软件,文章介绍了ISIS/Draw2.5的功能和特点,并通过其在计算机辅助筛选牛蒡子苷元结合蛋白中的应用,介绍了ISIS/Draw 2.5的使用技巧。     

双向拉伸聚丙烯薄膜

双向拉伸聚丙烯薄膜（ＢＯＰＰ）是一种综合性能好的材料，适用于包装行业。近年来，其在全球的生产量逐年递增。ＢＯＰＰ薄膜适用范围，它的生产具有经济性和有效的实用性。     

Draw resonance involving rheological transitions

The periodic diameter variations in melt spinning known as draw resonance have been extensively studied, both theoretically and experimentally. The theory has evolved from analyses for isothermal, Newtonian spinning in which the critical draw ratio was found to be 20.21. Compared with this, recent theories have shown that elasticity and cooling are stabilizing (with certain qualifications on the range of variables) and that non-linear rheological response is destabilizing. The present work presents systematic data on two polymers, one that is always amorphous (polystyrene) and one that solidifies into a semi-crystalline state (polypropylene). Isothermal and non-isothermal data are available for the former; non-isothermal data, for the latter. The melt temperature, the cooling environment, the die length, the spinning length, the mass flow rate and the draw ratio were varied. Certain observations cannot be explained within the existing theoretical framework, specifically the destabilizing effect of certain cooling histories in the case of polystyrene and the destabilizing effect of short dies, presumably a die swell effect, in the case of polypropylene. Very highly oriented polystyrene can be produced under certain conditions when the fiber temperature is held above T_g.     

Clar Formulas: How to Draw and How not to Draw Formulas of Polycyclic Aromatic Hydrocarbons

Historically, the aromatic sextet originates with Crocker (2), Armit and Robinson (3), and Hückel (4). The inscribed circle for denoting an aromatic sextet was introduced by Armit and Robinson, but it was Clar who defined how the sextet was to be used in polycyclic aromatic compounds. However, in some papers a mistaken form of Clar formulas is found. The present note stipulates that such mistakes should be corrected before their acceptance in respectable scientific journals, including this Journal.     

Draw resonance in polypropylene melt spinning

An attempt is made to gain better physical insight on the draw resonance phenomenon occurring during melt spinning of polypropylene (PP). An experimental study is first carried ouit to determine effects of spinning variables and material parameters on draw resonance, using two PRO-FAX PP resins and one PRO-FAX/LDPE blend. Based on the experimental observations, our view on the cause of draw resonance is presented. With this new concept, we are able to explain various aspects of the draw resonance phenomenon observed experimentally during melt spinning of PRO-FAX PP resins. It is concluded that the extensional viscosity versus strain relationship, as determined by an extensional rheometer, is one of the most valuable rheological measurements in analyzing flow instability occurring during polymer processing operations that utilize extensional flows.     

腈纶NaSCN一步法生产中调整喷丝头负拉伸率的研究

采用硫氰酸钠为溶剂,湿纺一步法工艺生产腈纶,探讨了喷丝头负拉伸率对纤维成形的影响。工业化试验表明:当喷丝头负拉伸率为-73％时,纤维可纺性达到最佳状态。     

拉丝机步进控制器故障探讨

介绍南京拉丝机步进控制器在使用中的故障现象和解决办法．提出日常维护措施     

聚丙烯酸钠汲取液的正渗透性能

研究了聚丙烯酸钠溶液作为汲取液的渗透压特性,并考察了影响水通量和溶质反向渗透量的因素和机制. 结果表明,聚丙烯酸钠浓度与渗透压的关系符合维里方程,第二维里系数对渗透压有较大贡献,聚丙烯酸钠溶液浓度为0.2 g/mL时的渗透压达1.3 Osmol/kg以上,水通量为14.5 L/(m2×h),略高于相同渗透压的氯化钠汲取液[14.0 L/(m2×h)];聚丙烯酸钠汲取液的溶质反向渗透量为1.6 g/(m2×h),低于常规氯化钠汲取液的16.5 g/(m2×h). 升高温度能迅速提高水通量,反向溶质渗透量维持在较低水平,聚丙烯酸钠汲取液适合比常规小分子汲取液更高的操作温度. 聚丙烯酸钠汲取液较高的水通量和较低的溶质反向渗透量表明正渗透性能良好.     

锦纶6拉伸变形丝退绕性能的改善

为解决锦纶6拉伸变形丝(DTY)在退绕过程中易出现打结、断头的问题,从锦纶6 DTY的加工工艺、设备部件等方面入手,确定了加工常规78 dtex/24 f DTY时,在保证无毛丝、紧捻、网丝、弹性均匀的前提下,设定超喂率为3.0%,交叉角为22°,卷装硬度达到68 HS时,退绕速度可大幅提高,达到1800 m/min。