首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 625 毫秒
1.
用混合溶剂方法,合成了5种对位取代的四苯基卟啉配体,收率范围为23%~52%,对卟啉配体进行轴向金属化反应得到含有中心金属离子(铁、钴、锰)及轴向氯配位的一系列金属卟啉化合物(金属化收率为90%~98%),并用红外光谱、紫外-可见光谱及核磁氢谱对所合成的卟啉化合物进行了结构表征.首次研究了金属卟啉催化分子氧在无溶剂绿色条件下氧化对甲基异丙苯.结果表明:对甲氧基四苯基卟啉和对氯四苯基卟啉的两价钴配合物的催化氧化活性较强.  相似文献   

2.
通过对比研究卟啉单体、 二聚体及金属卟啉单体的瞬 态光电压性质, 发现其光生电子-空穴对完全分离的时间: 单体小于二聚体, 卟啉配体小于金属卟啉. 卟啉配体电荷载流子缓慢衰减, 而金属卟啉在短时间内, 电子在接近半导体表面空间电荷区域里实现了载流子的快速分离. Cu卟啉的光生电荷载流子瞬态光电压信号与卟啉配体有相似之处, 且与其他金属卟啉也有相似之处. 在金属离子Co2+,Ni2+,Cu2+,Zn2+的影响下, 电子-空穴对开始分离的时间大约在2×10-7 s, 负信号是由接近半导体表面空间电荷区域内快速载流子分离所致, 金属卟啉中心离子d电子数不同, 光生电荷载流子快速分离时间也略有不同.  相似文献   

3.
鸡蛋白中的转铁蛋白具有清除过氧自由离子的功能.为了考察这些蛋白质在金属卟啉催化剂催化氧化反应中是否有增效作用,用鸡蛋白固载金属卟啉制备了鸡蛋白四苯基钴卟啉固体催化剂,研究其催化氧化乙醇选择性生成乙醛和乙酸的能力,考察反应时间、温度和压力对其催化性能的影响,并用紫外可见光谱( UV-Vis)及傅立叶红外吸收光谱(FT-I...  相似文献   

4.
设计、合成了15种取代四苯基(铁、钴、锰)卟啉仿生催化剂,并用红外光谱、紫外光谱等进行了结构表征.在温和条件下,将其用于催化氧气液相氧化对硝基甲苯制取对硝基苯甲酸.考察了各种金属卟啉催化剂的活性,发现其催化活性随着环外取代基吸电子能力的增强而增大.进一步采用量子化学半经验PM3计算法对上述金属卟啉催化剂进行了计算,与其催化活性对比,发现金属卟啉分子微观结构参数与其催化活性具有很大的相关性.从理论上阐述了金属卟啉催化剂催化活性强弱的原因.  相似文献   

5.
为研究多孔壳聚糖金属卟啉选择催化氧气氧化甲苯的能力,以壳聚糖通过盐键和配位键固载四(p-磺酸钠苯基)锰卟啉,用UV-Vis和FT-IR波谱技术、TEM和TG对该催化材料进行结构表征,在无外加溶剂和助催化剂条件下探索其催化性能。结果表明:在优化反应条件(温度180℃,压力0.8MPa)下,多孔壳聚糖四(p-磺酸钠苯基)锰卟啉催化氧化甲苯的转化率为15.3%,醛醇产率5.5%,多孔壳聚糖四(p-磺酸钠苯基)锰卟啉对甲苯的催化效能分别比无孔壳聚糖四(对-磺酸钠苯基)锰卟啉和四(对-磺酸钠苯基)锰卟啉的提高了16.8%和49.3%。壳聚糖通过盐键和配位键固载金属卟啉提高了金属卟啉的重复使用性能,并增强了催化甲苯的能力。  相似文献   

6.
四(对甲氧基苯基)卟啉钴的合成及表征   总被引:1,自引:1,他引:0  
以对甲氧基苯甲醛与吡咯为原料、丙酸为溶剂、氯乙酸为催化剂,合成四(对甲氧基苯基)卟啉及其钴配合物,用元素分析、紫外-可见光谱、红外光谱、1H核磁共振对化合物进行表征.结果表明,所合成的四(对甲氧基苯基)卟啉及四(对甲氧基苯基)卟啉钴配合物的结构与设计的结构相符;该配体及配合物的荧光光谱数据表明,相对荧光强度是四(对甲氧基苯基)卟啉四(对甲氧基苯基)卟啉钴四苯基卟啉.  相似文献   

7.
为研究[Co TCPP/ZnO]在无任何溶剂和还原剂的条件下催化氧化甲苯的性能,采用沉淀—烘焙法制备了氧化锌固载四(4-羧基苯基)钴卟啉[Co TCPP/ZnO]催化剂,并用UV-Vis、FT-IR和XRD技术对其进行了表征。结果表明:在较适宜反应温度180℃和压力0.6 MPa条件下,用仅含1.89×10-6mol Co TCPP的氧化锌四(4-羧基苯基)钴卟啉就可连续催化11次,催化效能平均值为:甲苯转化率6.84%,选择性50.47%,转化数6.52×104,比未固载的Co TCPP具有更好的催化性能和重复使用性能。这表明载体氧化锌对四(4-羧基苯基)钴卟啉[Co TCPP]具有良好的促进其催化能力和保护金属卟啉免遭氧化破坏的作用。  相似文献   

8.
以丙酸为溶剂,吡咯与4-取代苯甲醛反应合成5,10,15,20-四(4-取代苯基)卟啉.根据卟啉Soret带和Q带的特点,用紫外可见光谱协助监测柱层析中满足特征谱带的流出组份,快速分离纯化卟啉.以5,10,15,20-四(4-甲氧羰基苯基)卟啉为配体,与不同金属离子反应得到金属卟啉,对其进行可见光降解有机污染物罗丹明B...  相似文献   

9.
用红外、紫外及其漫反射光谱对催化剂的结构进行了测定。载体使金属卟啉吸收峰红移10-30nm,与推电子基的效应相一致。漫反射光谱证实聚合物负载的铁卟啉、锰卟啉、铬卟啉生成了氧络金属卟啉,面负载化铜卟啉、钴卟啉未生成相应的氧络金属卟啉。红外光谱进一步证实了金属卟啉与载体间的相互作用。  相似文献   

10.
用稀土乙酰丙酮配合物与配体meso-四[对-(4-氟苯氧基苯基)]卟啉进行配体交换反应,制得镧系乙酰丙酮-meso-四[对-(4-氟苯氧基苯基)]卟啉新型配合物,Ln[(FBOP)4P]acac(Ln:镧系元素Dy,Ho,Er,Tm;FBOP:4-氟苯氧基苯基;P:卟啉;acac:乙酰丙酮),并进行了组成和结构的表征.结果表明,配合物是由一个中心稀土离子,一个双齿轮配位的乙酰丙酮和一个四齿配位的四[对-(4-氟苯氧基苯基)]卟啉组成的,由于稀土离子位于卟啉平面之上,因此,形成一个立体型的大环分子配合物。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号