盐酸二甲双胍中双氰胺检测方法的改进

采用薄层色谱法，以８５％乙醇为溶液，以氯仿－甲醇－水（１６：１０：５）为流动相，以硅胶Ｇ为固定相，测定了盐酸二甲双胍中双氰胺，结果与部标方法一致，本法与部标方法比较，具有简便，快速，灵敏，所用试剂毒性小等特点。     

市场动态

上海化工市场行情据本刊编辑部对上海市场６２种化工产品价格的统计分析，１月中旬与１月上旬相比，有４种价格（指最低价－最高价，下同）上涨， ４４种价格持平，１４种价格下跌。各品种的具体价格情况是： 平均价格上升的品种净水醋酸丁酯（部标），６８００～７０００元（吨价，下同）；聚碳级双酚Ａ，９８００～１００００元；进口 ＡＢＳ， １２０００～１４０００元；上海氯碱公司产ＰＶＣ，６８００～７８００元。 平均价格持平的品种一级净水冰醋酸，３９００－４１００元；一级亚硝酸钠，２０００－２８００元；净水辛醇（部标）…     

木屑物理法生产活性炭新工艺

本文报道以木屑为原料，炭化后成型再活化生产活性炭的工艺。其质量达到部标，得率比原工艺大为提高，为浙江省林科所胡福昌工程师的专利－斜板炉再生活性炭提供了一种新的原料。     

高效液相色谱法测定2,4—二氯氟苯

应用甲醇：水＝９０：１０为流动相，在Ｓｈｉｍ－Ｐａｃｋ Ｃ１８柱上，以甲苯为内标物，于２５４ｎｍ下检测，建立了以２，４－二硝基氟苯为原料合成的２，４－二氯氟苯的高效液相色谱分析方法。该方法的相对标准偏差为２．１‰，２，４－二氯氟苯进样量在０．４－８．０μｇ范围内呈良好线性关系。     

2-甲基-4''-硝基二苯醚合成方法改进

以聚乙二醇（PEG600）为相转移催化剂，对硝基氰苯和邻甲酚为原料固－液法合成了2－甲基－4‘－硝基二苯醚。采用统计序贯实验设计方法寻优，得到最佳配比为，对硝基氰苯：邻甲酚：催化剂＝1：1．18：0．12（摩尔比），反应时间为6h。实验结果表明，该工艺反应平稳，2－甲基－4‘－硝基二苯醚的收率达到92．3％以上。     

高效液相色谱法测定2，4－二氯氟苯

应用甲醇：水＝９０：１０为流动相，在Ｓｈｉｍ－ＰａｃｋＣ１８柱上，以甲苯为内标物，于２５４ｎｍ下检测，建立了以２，４－二硝基氟苯为原料合成的２，４－二氯氟苯的高效液相色谱分析方法。该方法的相对标准偏差为２．１‰。２，４－二氯氟苯进样量在０．４～８．０μｇ范围内呈良好的线性关系（ｒ＝０．９９９９）。     

N-甲基乙酰氧基乙酰苯胺的液谱分析

本文研究了高效液相色谱测定N－甲基乙酰氧基乙酰苯胺的方法。采用Hypersil C18柱，以甲醇：水＝60：40（V／V）为流动相。该方法的变异系数为0．43％，回收率为98．9％－100．6％。     

3,3''-二氨基-4,4''-二羟基联苯的分析

采用高效液相色谱法，在C－18柱上，以甲醇－水（体积比为55：45）溶液为流动相，检测波长为265nm，测定了3，3‘-二氨基－4，4‘-二羟基联苯的含量。该法简便、快速，是监控反应的较好方法。     

邻硝基对甲酚和对甲酚的高效液相色谱法分析

采用高效液相色谱法（HPLC）分析邻硝基对甲酚工业品和原料对甲酚。以SpherisorbODS为固定相，柱温50℃，甲醇－水（体积比38：62）为流动相进行分离，紫外检测器在276nm波长下检测。本方法简便、准确     

冠醚相转移催化逆醇醛缩合反应——6—甲基—5—庚烯—2—酮的合成

6－甲基－5－庚烯－2－酮是重要的有机合成中间体和工业生产原料。其合成方法有：（1）以异成二烯为原料，经与氯化氢加成得到4氯－2－甲基－2－丁烯，再与丙酮在相转移催化剂（PTC）的存在下缩合得到。此法被认为是目前工业生产的最好方法［1，2］；（2）以有CEC三键的Wittig试剂，在汞盐的存在下与丙酮作用制得[3]；（3）以柠檬醛为原料，在碱溶液中常压、回流温度下[4]（或水溶液中高温加压下[5]）进行逆醇醛缩合反应而制得。后者的反应式为：在实验室制取6一甲基一5一庚烯一2一酮，选用第三种方法是比较合适的，它原料易得，且操作简…     

导流管结构对三相环流反应器相含率的影响

本文阐述了分别在三套内环流反应器内,采用空气—水—石英砂三相物系,导流管外径依次取为75mm和60mm,导流管底隙高度为17mm和30mm.研究了在一定的固相质量分数及初始静液高度下,导流管内局部相含率与表观气速的随动关系以及在固定操作气速下相含率在导流管内的轴向分布情况.经装置间平行比对得出:采用75mm外径的导流管...     

非水微乳体系相图研究

研究了以甲醇或甲酰胺为极性相,正辛烷为油相,添加不同HLB值的表面活性剂形成的非水微乳体系的三元相图.结果表明,具有适当HLB值的表面活性剂可与正辛烷、甲醇或甲酰胺形成单相区,亲水性强的表面活性剂不利于形成单相微乳体系;在m(表面活性剂):m(正辛烷)=1∶4,甲醇(甲酰胺)增溶量为最大增溶量的50％时,各微乳液相点的粒径在20～60 nm.     

气相法聚乙烯冷凝模式操作的模拟研究(Ⅰ) 反应器运行状态的分析

建立了气相法聚乙烯冷凝模式操作反应器的两相模型 .模型涉及气泡相和乳化相中的热量和质量守衡、乳相和泡相之间的热量传递和质量传递、乳相中的聚合反应以及乳相中粒子的停留时间分布等 .通过模型研究了常规操作和冷凝操作时操作变量和反应器运行状态变量之间的关系 .模型模拟结果与工业的常规操作和冷凝操作数据符合较好 .得到了冷凝操作时时空收率、低温区域、聚合物灰分等的变化规律以及催化剂特性对冷凝操作的影响规律 .提出了适合于冷凝操作的催化剂类型     

Liquid-liquid phase transition in flow systems

Liquid-liquid phase transition is occurring in many chemical engineering processes either as a desired phenomenon or as an undesired side effect. Typically, the phase split is modeled by neglecting all non-equilibrium effects. Here, a simple non-equilibrium situation is considered. Convective flow of a liquid along a decreasing temperature profile in a cooled channel is studied analytically. Three different scenarios for the transition process with two typical phase diagrams for binary mixtures are examined. For a phase diagram with critical concentration, phase segregation occurs via spinodal decomposition as a convective instability. For a cigar-shaped phase diagram the phase transformation is shown to evolve in analogy to directional solidification. Finger-like structures may be established under certain circumstances.     

Behaviour of liquid/liquid/solid three-phase fixed bed reactors with application in biocatalysis

Fixed bed reactors operated by feeding with two immiscible liquids are of increasing importance in chemical as well as biochemical reaction engineering. Based on biocatalysis studies, liquid/liquid/solid three-phase fixed bed reactors have been assessed with respect to the phase distribution in such reactors and the backmixing in each liquid phase. The systems were characterized by the presence of a continuous aqueous phase. The phase distribution in the reactor differed substantially from that in the feed stream, particularly when the feed had a low content of non-polar solvent. The accumulation of the non-polar phase in fixed beds of particulate solids was accompanied by blocking of the interstitial void volume by, and channelling of, the non-polar phase as well as enhanced backmixing of both the aqueous and the non-polar phase. Studies with various non-polar solvents demonstrated that the choice of organic solvent is important for the operation of three-phase fixed bed reactors. © 1998 SCI     

超声波促进新型席夫碱类化合物的水相合成

在超声波促进下以聚乙二醇(PEG 6000)为相转移催化剂,在水相中合成了8个席夫碱类化合物。采用1HNMR、13CNMR、IR、MS(ESI)和X-射线衍射对其结构进行了表征,结果与目标化合物一致。采用相转移催化剂水相超声波合成,与传统的加热反应或有机溶剂相超声波合成比较,水相超声波合成不但可以避免使用酸碱催化剂和乙醇等挥发性溶剂,而且使得反应时间从数小时缩短至0.5 h左右,产率高达76%~92%。经查证,其中6个席夫碱类化合物是未见文献报道的新化合物。     

天然矿高岭土制备莫来石复合纳米晶微观结构表征

天然矿高岭土经除杂质,除铁,除碳系列处理后,制得了主晶相为莫来石的复合氧化物,经水热晶化法合成了纳米级莫来石复合氧化物。利用ＸＲＤ,ＴＥＭ及ＢＥＴ表征了纳米复合氧化物的物相及显微结构。     

硅基正弦波纹微通道内的流动阻力特性

硅基正弦波纹微通道在微尺度强化换热、微流体器件中均有重要运用,而目前尚未见有关于其内部流动特性的实验报道。利用标准微机电系统（MEMS）工艺在硅基芯片上加工制成一系列具有不同相位差和周期、当量直径为160 μm的正弦波纹微通道,通过实验研究了其内部流动阻力特性。研究表明：正弦波纹微通道较平直微通道阻力均有增加,且增加幅度与波纹微通道两侧壁的相位差和周期有关。对于周期相同的波纹微通道,两侧壁相位差越大,阻力也越大。对于相位差相同的波纹微通道,周期对阻力的影响则较为复杂：当相位差为0时,呈现出周期越大、阻力越小的趋势（除最小周期通道外）;当相位差为π时,呈现出周期越大、阻力越大的趋势。研究还发现：随着周期减小,相位差对阻力的影响减小,当周期缩短至0.5 mm时,相位差为0和π的波纹微通道内的阻力特性曲线几乎重合。     

Lithium orthosilicate ceramics with preceramic polymer as silica source

Lithium orthosilicate ceramics powders were synthesized using a preceramic polymer as the source of silica. Stoichiometric, as well as batches lean and rich in lithium, were prepared by the said approach to understand the thermal stability of the orthosilicate phase at 1000 °C. All of the batches produced phase pure orthosilicate ceramics with sintered density up to 82%. However, different batches showed markedly different microstructural evolution with the lithium lean and stoichiometric compositions exhibiting formation of flower-like lithium metasilicate phase. The lithium rich composition showed no phase separation of the orthosilicate ceramic phase as confirmed by electron microscopy and x-ray diffraction. The high volatilization of the lithium species at high temperature was ascribed to the phase separation of the orthosilicate phase in the lithium lean compositions. The current report provides an alternative and novel method to fabricate lithium orthosilicate, and shows promise for application as tritium breeding blankets in fusion technologies.     

中空纤维支撑液膜萃取Cu(II)的传递性能

The transport of Cu(II) from aqueous solutions containing buffer media through hollow fiber supported liquid membrane (HFSLM) using di(2-ethylhexyl) phosphoric acid (D2EHPA) dissolved in kerosene as membrane phase and hydrochloric acid as striping phase was investigated. A set of factors were studied, including tube side velocity, shell side velocity, pH of the feed phase, Cu(II) concentration in the feed phase, buffer media concentration and D2EHPA concentration in the membrane phase. Experimental results indicate that the mass transfer coefficient increases with increasing both carrier concentration in the organic phase and flow rates on the tube side and shell side, and decreases with increasing initial Cu(II) concentration in the feed phase. With increasing pH value and acetate concentration in the feed phase, the mass transfer coefficient reaches a maximum value then decreases. The optimal operating conditions are obtained at pH value of 4.44 and 0.1 mol&;#8226;L－1 acetic ion concentration in feed phase, and carrier volume fraction of around 10% in kerosene as organic phase. A mathematical model of the transport mechanism through HFSLM is devel-oped. The modeled results agree well with the experimental ones.