排序方式: 共有42条查询结果,搜索用时 23 毫秒
21.
22.
TiCl4水解法制备的阻挡层对染料敏化太阳能电池光电性能的影响 总被引:1,自引:0,他引:1
通过不同浓度的TiCl4溶液水解, 在光阳极导电玻璃(FTO)基底上制备了阻挡层薄膜, 以此来抑制FTO表面的光生电子与I3-之间的复合反应, 采用X射线光电子能谱(XPS)和X射线衍射分别测试了阻挡层薄膜的组成, 用场发射扫描电子显微镜(FE-SEM)和紫外-可见(UV-Vis)分光光度计测试了阻挡层的形貌和对光的透过率, 在AM1.5和暗环境下分别测试了染料敏化太阳能电池(DSSC)的光电性能. 实验结果表明: 用此方法可以获得由TiO2粒子组成的阻挡层薄膜; 阻挡层薄膜的形貌随着TiCl4溶液浓度的增加而改变, 它的厚度随着TiCl4溶液浓度的增加而增加; 引入阻挡层后, FTO对光的透过率都会下降; 这一薄膜的引入可以提高电池的光电性能, 用0.04 mol·L-1的TiCl4溶液制备的阻挡层对暗电流的抑制作用最为明显, 电池在AM1.5的条件下测试, 转换效率最高达7.84%. 相似文献
23.
A synthetic strategy toward the cyclic addition of 2,2′‐dihydroxybiphenyl to terminal alkynes has been developed using Lewis acid TiCl4 as catalyst. The reactions generated dibenzo[d,f][1,3]dioxepines derivatives in good yields with excellent regio‐selectivity in the presence of catalytic amount of TiCl4 under mild reaction conditions. 相似文献
24.
Young Soo Ko Taek Kyu Han Je Woo Park Seong Ihl Woo 《Journal of polymer science. Part A, Polymer chemistry》1997,35(13):2769-2776
MgCl2/THF/TiCl4 (TT-0) were thermally pretreated at 80°C for 5 min (TT-1) and 60 min (TT-2), and at 108°C for 5 min (TT-3) and 60 min (TT-4). These thermally pretreated catalysts showed comonomer enhancement effects in the ethylene-1-hexene copolymerization, while TT-0 catalyst did not. Comonomer enhancement effect of thermally pretreated catalysts could come from the generation of new active sites and change of its nature after heat treatment. 1-Hexene content in copolymer obtained with TT-1 was higher than those of TT-4 and TT-0. The morphology of homopolyethylene (PE) obtained with TT-1, 2, 3, and 4 was more regular and homogeneous than that of TT-0. This result could be due to the generation of active sites and change of its nature after thermal treatment of bimetallic catalyst. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2769–2776, 1997 相似文献
25.
SHANG Yan-mei LI Jing SONG Zhi-guang LI Ye-zhi HUANG Hua-min 《高等学校化学研究》2007,23(4):430-432
A series of esters of R-tetrahydrothiazo-2-thione-4-carboxylic acid[R-TTCA] was synthesized by direct esterification of R-TTCA with alcohols(CH3OH,C2H5OH,n-C3H7OH,i-C3H7OH,n-C4H9OH,sec-C4H9OH)in the presence of TiCl4 as the catalyst at room temperature without using any other solvent or dehydrant in high yields,91.6%-99.1% for primary alcohols and 55%- 80% for secondary alcohols.The catalyst has a strong chemoselective activity for the esterification of primary alcohols with R-TTCA in the presence of secondary alcohols.Owing to high yield,high chemoselectivity,and mild conditions used,this is an efficient method for the esterification of primary alcohols with R-TTCA. 相似文献
26.
Azo compounds were conveniently reduced by a system consisting of Sm/TiCl4 to produce aniline anions. This anion species reacted smoothly with aliphatic acyl chlorides or acid anhydrides to afford corresponding amides under mild and neutral conditions. 相似文献
27.
研究了几种有机钛化合物对草酸二甲酯(DMO)与苯酚酯交换反应的催化性能,发现催化活性及选择性顺序依次为二氯二茂钛>钛酸四苯酯>钛酸丁酯>乙酰丙酮氧钛>钛酸乙酯>钛酸异丙酯,表明二氯二茂钛是一种性能较好的酯交换催化剂。在n(Cp2TiCl2) = 0.001 mol、n (DMO) =0.3mol、n (Phenol) = 0.2mol、T=180癈、t=2h优化工艺条件下,苯酚转化率可达44.0%,甲基苯基草酸酯(MPO)和草酸二苯酯(DPO)收率分别达37.8%和6.1%,酯交换总选择性为99.8%。 相似文献
28.
In a rational chiral molecular design of chalcogenides, optically active thiepin with C2‐symmetric chirality was synthesized from commercially available thiophene. Then enatioselective Chalcogeno‐Baylis‐Hillman reactions of arylaldehydes with methyl vinyl ketone (MVK) and acrylates were investigated in the presence of thiepin‐Lewis acid complex. Finally, up to 64% ee was achieved in the presence of 0.2 equiv. of (S)‐thiepin at 20°C. 相似文献
29.
30.
Polyolefins represented by polyethylene (PE) and polypropylene (PP) are indispensable materials in our daily lives. TiCl3 catalysts, established by Ziegler and Natta in the 1950s, led to the births of the polyolefin industries. However, the activities and stereospecificities of the TiCl3 catalysts were so low that steps for removing catalyst residues and low stereoregular PP were needed in the production of PE and PP. Our discovery of MgCl2‐supported TiCl4 catalysts led to more than 100 times higher activities and extremely high stereospecificities, which enabled us to dispense with the steps for the removals, meaning the process innovation. Furthermore, they narrowed the molecular weight and composition distributions of PE and PP, enabling us to control the polymer structures precisely and create such new products as very low density PE or heat‐sealable film at low temperature. The typical example of the product innovations by the combination of the high stereospecificity and the narrowed composition distribution is high‐performance impact copolymer used for an automobile bumper that used to be made of metal. These process and product innovations established these polyolefin industries. The latest MgCl2‐supported TiCl4 catalyst is very close to perfect control of isotactic PP structure and is expected to bring about further innovations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1–8, 2004 相似文献