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由山苍子油合成甲基紫罗兰酮 总被引:6,自引:1,他引:5
研究用山苍子油提取得到的柠檬醛和 2 -丁酮等为主要原料在季铵碱存在下合成假性异甲基紫罗兰酮 ,以固载强酸 Ti O2 /SO2 -4作催化剂 ,用假性异甲基紫罗兰酮合成甲基紫罗兰酮的新方法。提高了 α-异甲基紫罗兰酮的收率 ,获得了最佳反应条件 :投料比 n(假性异甲基紫罗兰酮 )∶n(二甲苯 )∶ n(硫酸 ) =1∶ 3.5∶ 0 .0 4 ,控制反应温度 1 5~ 2 5°C,反应时间 1 .5 h。该优化条件下 ,合成收率为 92 %~ 93% ,产物中α-异甲基紫罗兰酮质量分数为 77%左右。 相似文献
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由柠檬醛合成柠檬腈的工艺研究 总被引:5,自引:0,他引:5
从山苍子提取出的柠檬醛 ,与硫酸羟胺反应生成柠朦肟 ,脱水后可得到柠檬腈。通过正交实验确定了柠朦肟合成的最佳工艺条件是 :n(柠檬醛 )∶n(硫酸羟胺 ) =1∶ 1 .5 ,p H=6~ 7,反应温度为 45°C,反应时间 3 .5 h。柠朦腈合成的最佳工艺条件是 :n(柠檬肟 )∶ n(乙酸酐 ) =1∶ 5 ,反应温度为 1 2 5~ 1 3 0°C,反应时间 1 h。柠檬腈的产率约为 89.7%。 相似文献
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报道了用化学溶液沉积法采用价格低廉的原料在电阻率为 6~ 9Ω·cm的 n型 Si( 1 0 0 )衬底上生长 Bi4 Ti3 O12 铁电薄膜 ,并对薄膜的性质进行了研究。结果表明此制膜工艺简单 ,成本低 ,制备的 Bi4 Ti3 O12 铁电薄膜具有较低的结晶温度 ,且薄膜均匀 ,致密 ,无裂纹。在 650°C下退火 30 min时得到的 Bi4 Ti3 O12 铁电薄膜具有良好的绝缘性和铁电性 ,薄膜的剩余极化 Pr=4.9μC/cm2 ,矫顽电场 Ec=87k V/cm 相似文献
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含镍的SiO2溶胶-凝胶的制备 总被引:5,自引:1,他引:5
以正硅酸乙酯 (TEOS)为原料、草酸 (C2 H2 O4)为催化剂 ,通过水解、缩聚反应制成了含镍的二氧化硅溶胶 -凝胶。探讨了温度及草酸、水、乙醇的用量对正硅酸乙酯水解过程的影响。结果表明 ,制备含镍的SiO2 溶胶 -凝胶的最佳工艺是 :n(TEOS)∶n(C2 H5OH)∶n(H2 O)∶n(C2 H2 O4) =1∶4∶8∶0 8× 10 -4~ 16×10 -4,n(H2 O) /n(TEOS) =4~ 18,n(C2 H5OH) /n(H2 O) =1~ 2 ;水解温度 30~ 4 0℃。 相似文献
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采用溶胶-凝胶法制备Na1/2La1/2Cu3Ti4O12 (NLCTO)粉体和陶瓷样品,探讨不同Ti4+浓度、pH值和水含量对NLCTO粉体和陶瓷结构的影响.结果表明在Ti4+浓度为0.75~1.0 mol/L,pH=0.3~1.3,[H2O]/[Ti4+]=11∶1的条件下制备的干凝胶在800 ℃预烧后,粉体分散程度较好,颗粒均匀.在获得优越NLCTO粉体基础上制备的陶瓷材料介电常数约可达到1.9×104以上,介电损耗降低到0.039. 相似文献
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富纳米孔炭质吸附剂的制备及其吸附天然气的性能研究 总被引:7,自引:0,他引:7
以石油焦为原料 ,在m(KOH)∶m(C) =2∶1的条件下 ,以KOH为主活化剂 ,以H2 O作为活化助剂 ,制备出富含纳米孔的天然气吸附剂。实验得到的预活化条件是 :m (KOH)∶m(C) =2∶1;m(H2 O)∶m(C) =1∶1,32 0℃保持 4 0min ,然后升温至 35 0℃保持 10min。活化条件是 :8℃ /min的升温速度 ,升温至 82 0℃保持 90min后 ,降温至 30 0℃后取料。结果表明 ,按此条件得到的产品微孔 (1~ 2nm)率可达 90 %以上 ,产品的质量吸附量在 2 0℃、3 5MPa下达到 13 8%。 相似文献
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纳米TiO2的溶胶—凝胶法制备改进及粒径控制 总被引:1,自引:1,他引:0
以无机钛盐淡前驱体,PEG和淀粉为分散剂,分别用溶胶-凝胶法及改进溶胶-凝胶法制备出纳米TiO2粉体,在改进方法中,用溶解凝胶而不是传统的高温灼烧凝胶的方法得到TiO2。所得的产物是极细(4nm)并已明显开始结晶(锐钛矿)的TiO2粉体,此粉末可用作加热法控制TiO2颗粒尺寸的起始物质。TiO2在极低温度(≤100℃)下结晶被推测为由聚合物与Ti(NO3)4交联组成的凝胶结构比 较特殊所致。在改进的方法中少量的NO2气体可被容易地吸收,同时,重复溶解的聚合物可重复和利用。因此,这种方法在工业生产中有利于环境保护。 相似文献
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TiSiW_(12)O_(40)/TiO_2催化合成丁酮1,2-丙二醇缩酮 总被引:1,自引:0,他引:1
报道了以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂,通过丁酮和1,2-丙二醇反应合成了丁酮1,2-丙二醇缩酮,探讨了TiSiW12O40/TiO2对缩酮反应的催化活性,较系统地研究了酮醇物质的量比,催化剂用量,反应时间诸因素对产品收率的影响。实验表明:TiSiW12O40/TiO2是合成丁酮1,2-丙二醇缩酮的良好催化剂,在n(酮)∶n(醇)=1∶2.0,催化剂用量为反应物料总质量的0.3%,反应温度为82~110°C,环己烷为带水剂,反应时间2.0h的优化条件下,丁酮1,2-丙二醇缩酮的收率可达91.3%。 相似文献
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Qichun Sun Jun Yang Bing Yin Jun Cheng Shengyu Zhu Shuai Wang Yuan Yu Zhuhui Qiao Weimin Liu 《Journal of the European Ceramic Society》2018,38(7):2708-2715
High toughness integrated with self-lubricity of β-Sialon composites at elevated temperature containing second phase particles were successfully fabricated. It was found that the fracture toughness can be substantially improved by addition of Cu powder. The fracture toughness can be reached 6.75?MPa?m1/2 and 4.42?MPa?m1/2 at 25 and 900?°C, respectively. Meanwhile, the tribological properties of Cu-doped Sialons have a tremendous improvement at high temperature. Especially when the content of Cu powder is above 10?wt%, the wear rate decreases by two orders of magnitude and the friction coefficient reduces to 0.56–0.65 at 900?°C. In addition, the microstructure of composites was characterized, and crack propagation behavior and tribological behavior were discussed to clarify the toughening mechanisms and self-lubrication mechanisms. The results show that the principal toughening mechanisms are crack deflection and crack bridging. The tribo-chemical reaction and generated CuO films with lubricity are the main self-lubrication mechanisms. 相似文献
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阻燃剂V6的合成研究 总被引:1,自引:0,他引:1
以三氯化磷、季戊四醇、氯气及环氧乙烷为原料,四氯化钛为催化剂,通过三步反应合成了阻燃剂V6——四(2-氯乙基)-2,2-二(氯甲基)-1,3-亚丙基二磷酸酯。用IR、元素分析对合成的阻燃剂V6进行了表征,并且对各步的反应条件进行了优化,最佳反应条件为:反应物配比n(季戊四醇)∶n(三氯化磷)∶n(氯气)∶n(环氧乙烷)为1∶2.5∶2.2∶4.2;各步的最佳反应时间依次是2h,3h,4h;适宜的反应温度分别为80°C,23~25°C,80°C。产率达93.5%。 相似文献
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Gel Composition and Strength Properties of Alkali‐Activated Oyster Shell‐Volcanic Ash: Effect of Synthesis Conditions 下载免费PDF全文
Jean Noël Yankwa Djobo Hervé Kouamo Tchakouté Navid Ranjbar Antoine Elimbi Leonel Noumbissié Tchadjié Daniel Njopwouo 《Journal of the American Ceramic Society》2016,99(9):3159-3166
The gel composition and mechanical properties of alkali‐activated oyster shell‐volcanic ash were investigated at different NaOH concentrations (8, 12, and 15M) and curing temperatures (60°C and 80°C) in wet and dry conditions. XRD, FTIR, SEM‐EDS, and TGA‐DSC were used for microstructural characterization of the binder. The gel composition of the system was found to be influenced by NaOH concentration and was not affected when curing temperature was varied from 60°C to 80°C. The main phase was N,C–A–S–H for all alkali‐activated oyster shell‐volcanic ash, with C–S–H as secondary phase for some samples and contains high percentage of iron. The splitting at υ3 = 1400–1494 cm?1 on FTIR spectra corresponded to the elimination of the degeneracy due to the distortion of CO32? group. The high degree of splitting indicated that this carbonate group is linked to Ca2+. The compressive strength was influenced by curing temperature and the formation of a secondary phase. The compressive strength in dry condition increased roughly between 28 and 180 d for some samples, while in wet condition, the partial dissolution of Si–O–Si bonds of some silicate phases resulted in a reduction of strength. 相似文献
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Ce4+的掺杂和染料结构对TiO2光催化性能的影响 总被引:3,自引:0,他引:3
采用浸渍法制备了掺杂Ce^4 的TiO2粉体光催化剂,考察了Ce^4 的含量对TiO2光催化性能的影响,并且研究了它对直接耐晒蓝和4,2-(吡啶偶氮)-间笨二酚钠两种染料的降解效果。结果表明,以TiO2干凝胶为母体,浸渍Ce^4 所制备的粉体光催化剂Ce^4 /TiO2降解效果分别比纯TiO2高45%和23%其对偶氮基团的分解效果明显高于对吡啶环和间苯二酚基的分解。X射线衍射分析表明,该法制备的TiO2粉体中锐钛矿相占90%以上,没有铈的氧化物形式,平均晶粒粒径为1nm;红外吸收光谱分析表明,Ce^4 /TiO2和TiO2红外吸收光谱图相似,说明掺杂Ce^4 并没有极大地改变TiO2的化学结构。 相似文献
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Santosh K. Gupta Madhusudan Krishnadas Bhide Shrikant Vasant Godbole Venkataraman Natarajan 《Journal of the American Ceramic Society》2014,97(11):3694-3701
ThO2:Eu3+ nanoparticles were synthesized at 300°C by combustion route using urea as a fuel and characterized by thermogravimetric/differential thermal analysis, X‐ray diffraction, transmission electron microscopy, and photoluminescence techniques. To investigate the effect of annealing temperature, as synthesized powder were heated further at 500°C, 700°C, and 900°C. It was observed that extent of asymmetry around Eu3+ at 700°C/900°C is very high as compared to as‐prepared or 500°C annealed sample. Based on the time resolved emission spectroscopic investigations, it was inferred that two different types of Eu3+ ions were present in the ThO2 nanoparticles. In ThO2 structure, Eu3+ ions occupy two sites; cubic (Oh) and noncubic (<C2v) as can be confirmed from our emission studies. Short‐lived species T1 (~1.3–3.4 ms) predominates at higher annealing temperature arises because of Eu3+ ions occupying noncubic (<C2v) sites without inversion symmetry, whereas long‐lived species T2 (~4.6–6.6 ms) can be ascribed to Eu3+ ions occupying cubic sites (Oh) with inversion symmetry. 相似文献