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以咔唑为主要原料,经烃化、碘代、磺酰化、Ullmann反应和水解反应合成了3,6-二(3,6-二叔丁基咔唑基)-咔唑,五步反应总收率为50.3%,中间体及产品进行了1 HNMR检测。该合成工艺具有路线简单、操作方便、产率高等优点,适合大批量制备。 相似文献
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以4,4,-二溴联苯为原料经硝化、闭环、N-烷基化反应合成了2,7-二溴-N-辛基咔唑(3)。4,4,-二溴联苯与发烟硝酸按n(4,4,-二溴联苯)︰n(HNO3)=1.0︰4.0,在75 ℃下进行硝化,反应5 h,得到了2-硝基-4,4,-二溴联苯(1),收率97%;中间产物1与三苯基膦按n(2-硝基-4,4,-二溴联苯)︰n(三苯基膦)=1.0︰3.0,在无水无氧条件下,闭环得到了2,7-二溴咔唑(2),收率68%;在碱性条件下,中间产物2与1-溴辛烷按n(2,7-二溴咔唑)︰n(1-溴辛烷)=1.0︰1.5,N-烷基化反应合成最终产物,收率85%。产物结构经IR、元素分析和1H NMR确证。 相似文献
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以4,4'-二溴联苯为原料,经硝化、闭环、N-烷基化反应合成了2,7-二溴-N-辛基咔唑(Ⅲ)。4,4'-二溴联苯与发烟硝酸按n(4,4'-二溴联苯)∶n(HNO3)=1.0∶4.0,在75℃下进行硝化,反应5 h,得到了2-硝基-4,4'-二溴联苯(Ⅰ),收率97%;中间产物Ⅰ与三苯基膦按n(2-硝基-4,4'-二溴联苯)∶n(三苯基膦)=1.0∶3.0,在无水无氧条件下,闭环反应得到了2,7-二溴咔唑(Ⅱ),收率85%;在碱性条件下,中间产物Ⅱ与1-溴辛烷按n(2,7-二溴咔唑)∶n(1-溴辛烷)=1.0∶1.5,N-烷基化反应合成最终产物,收率85%。产物结构经IR、元素分析和1HNMR确证。 相似文献
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以咔唑为原料 ,经碘代、N 烷基化、取代三步反应合成了 3,6 双 (二苯胺基 ) 9 乙基咔唑(Ⅲ )。咔唑与ICl按 m(咔唑 )∶ m(ICl) =1∶2 ,在 80℃进行碘代 ,反应 3h ,制取了 3,6 二碘代咔唑 (Ⅰ ) ,产率 6 1% ;中间产物Ⅰ与溴乙烷按m (Ⅰ )∶V(C2 H5Br) =8 5g∶2 5mL ,以DMSO为溶剂 ,在过量固体KOH存在下 ,80℃ ,反应 2h ,制备了 3,6 二碘代 9 乙基咔唑 (Ⅱ ) ,产率 40 % ;中间产物Ⅱ与二苯胺在铜粉和K2 CO3 催化剂存在下 ,m (Ⅱ )∶m (铜粉 )∶m (K2 CO3) =2 9∶0 2∶1 5 ,以硝基苯为溶剂 ,在 2 0 8℃回流 10h ,合成了最终产物Ⅲ ,产率 70 %。 相似文献
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A. G. Gopala Krishna 《Journal of the American Oil Chemists' Society》1992,69(12):1257-1259
The color of bleached rice bran oil can be improved by silica gel treatment of the oil miscella before or after dewaxing.
A silica gel/oil/solvent ratio of 1:5:5 (wt/wt/vol) is suitable. Silica gel treatment can be carried out either by column
percolation or by merely shaking the miscella with the gel followed by decantation. However, column percolation is more efficient,
with 30–72% color reductionvs. 19–36% reduction for shaking and decanting. 相似文献
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以乙醇和去离子水为溶剂,以正硅酸乙酯为原料,柠檬酸为络合剂,采用Pechini溶胶-凝胶法制备了超细二氧化硅粉体,采用热分析(TG-DTG、DSC)、X射线衍射(XRD)分析、傅里叶红外光谱(FT-IR)分析、场发射扫描电镜(FESEM)分析等对二氧化硅粉体制备过程中的物理化学变化进行了研究。结果表明:1 000 ℃以下煅烧所得二氧化硅粉体均为非晶相,pH影响了煅烧过程中有机物的降解燃烧;煅烧温度为500 ℃时,所得二氧化硅纳米粉体的粒径约为10 nm;煅烧温度升高至600 ℃时,粉体团聚严重,晶粒尺寸增大至20 nm。 相似文献
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Ramanath N. Bhat Rajiv Kumar 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1990,48(4):453-466
The feasibility of synthesising pure zeolite beta in high yields using silica gel as the source of SiO2 is demonstrated. The phase-purity and yield of beta is enhanced by using silica gels with high surface area. The influence of various synthesis parameters (Si/Al ratio, alkalinity, dilution level, concentration of the organic base, etc.) on the kinetics of synthesis as well as the quality and yield of the zeolite have been investigated. A correlation between XRD crystallinity of the samples with varying degrees of crystallinity and that estimated from framework IR spectroscopy, differential thermal analysis and adsorption of n-hexane is demonstrated. The dependence of the yield of zeolite beta on SiO2/Al2O3 ratio of the gel is also reported. The results of the present study indicate the feasibility of a cheaper route for the manufacture of zeolite beta. 相似文献
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以硅胶负载型Ti(SO4)2、Zr(SO4)2、Fe2(SO4)3、Se(SO4)2为催化剂,由柠檬酸和正戊醇合成新型增塑剂柠檬酸三戊酯,考察了各反应因素对酯化率的影响。结果表明,在柠檬酸与正戊醇物质的量比为1∶4.0,硅胶负载Ti(SO4)2用量为柠檬酸总量的3%,催化剂活化温度400℃,反应温度155~165℃和反应时间3.0 h条件下,柠檬酸三戊酯的酯化率可达到97.2%,纯度经气相色谱分析大于99%。催化剂硅胶负载Ti(SO4)2重复使用多次,活性未见明显降低。 相似文献
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Silica gels that controlled the pore size were prepared by calcination of silica/organic polymer (50/50 wt %) composites prepared by the sol-gel process. Poly(ethylene oxide) (PEO)-poly(propyrene oxide) (PPO)-PEO triblock copolymers, which are called poloxamers, were used as an organic polymer. The pore control of the silica gels was carried out by changing the molecular weight of PEO or PPO in the poloxamers. The silica gels obtained by the above procedure had a dual pore size of around 4 nm and below 2 nm in diameter, and the specific surface area was 500–1000 m2/g. The poloxamer molecules were supposed to be dispersed monomolecularly in the composites. Therefore, the pore structure of the silica gels reflected the structure of the poloxamer and, particularly, the radius of gyration of PPO in the composites. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 763–768, 1997 相似文献
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Devrim Balkse 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1990,49(2):165-171
Silica gels were obtained by drying the silica hydrogels formed at pH values between 1 and 4 at 100°C. The bulk density of the 2–3 mm diameter fraction decreased from 0·62 g cm?3 to 0·20 g cm?3 as the preparation pH increased from pH 3 to pH 3·65. The apparent density of silica gels was between 1·43 and 1·95 g cm?3. Isotherms for the adsorption of water vapour on samples prepared at different pH values showed hysteresis in all cases. Thermogravimetry analysis showed that the amount of bound water was in the range of 4·4 to 5·5% on a dry weight basis. Specific heats were determined by a differential scanning calorimetry method using a sapphire standard and were between 0·82 and 0·97 J g?1 K1. 相似文献
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以硅酸钠为硅源,运用溶胶-凝胶法制备出硅胶载体,采用液相浸渍法制备得到Cu2+/Tb2O3抗菌硅胶。选用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)等对材料进行表征,结果表明:Cu2+/Tb2O3抗菌硅胶结构蓬松多孔,铜以CuO/Cu(OH)2、铽以Tb2O3的形态负载于硅胶载体上。对样品进行最低抑菌浓度(MIC)和最小杀菌浓度(MBC)检测可知,添加稀土铽离子能有效提高抗菌硅胶的抑菌和杀菌性能。通过对材料的溶出液离子含量、比表面积和CuO晶粒尺寸研究发现,添加铽离子后材料中铜离子的溶出量从7.22mg/L增加到11.82mg/L,比表面积从115.5m2/g增加到129.3m2/g,CuO晶粒尺寸从107nm降低至76nm,并由此探讨铽离子对材料抗菌性能提升的作用机理。 相似文献