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1.
采用色谱法从蒲儿根花部位中分离得到2-甲基-6-(2-甲苯基)-2-庚烯,该化合物第一次以单体的形式得到,通过测定氢-氢相关谱(1H-1H COSY)、DEPT谱、异核单量子相关谱(HSQC)及异核多键相关谱(HMBC)等二维谱确定了该化合物的结构,并对该化合物的1H NMR和13C NMR谱进行了归属.  相似文献   

2.
利用可调谐真空紫外同步辐射和分子束实验装置在8.0~15.5 eV的光子能量范围内,研究2-甲基-2-内烯-1-醇的光电离解离.测出母体离子和碎片离子:C_4H_8O~+、C_4H_7O~+、C_3H_5O~+、C_4H_7~+、C_4H_6~+、C_4H_5~+、C_2H_4O~+、C_2H_3O~+、C_3H_6~+、C_3H_5~+、C_3H_3~+、CH_3O~+和CHO~+的光电离效率曲线,并获得母体分子的电离能和碎片离子的实验出现势.在B3LYP/6-31+G(d,p)理论水平上,计算光电离过程中母体分子、过渡态和中间体的稳定结构.采用CCSD(T)/cc-pVTZ耦合簇方法计算零点能,得到母体电离能和碎片离子的出现势.通过实验和理论研究,提出2-甲基-2-丙烯-1-醇的光解离路径,分子内氢转移是其中大部分解离途径中的主要过程.  相似文献   

3.
本文利用定容燃烧弹平台测量了不同初始温度(353,393和433 K)和初始压力(0.1,0.2和0.4 MPa)条件下的戊烯同分异构体(1-戊烯和2-甲基-2丁烯)的层流燃烧速率.实验结果表明1-戊烯的层流燃烧速率高于2-甲基-2-丁烯。本文对爱尔兰高威大学最新发表的戊烷同分异构体机理的1-戊烯和2-甲基-2-丁烯子机理进行了优化,利用优化后的机理进行了进一步的模拟工作。进一步的路径分析表明,1-戊烯的层流燃烧速率较2-甲基-2-丁烯快的原因主要是前者生成了较多的活性H自由基而后者生成了较多的H消耗中间产物和甲基.  相似文献   

4.
2-(2-喹啉偶氮)-4-甲基-1,3-苯二酚光度法测定铜的研究   总被引:2,自引:1,他引:1  
合成了新试剂 2 - (2 -喹啉偶氮 ) - 4-甲基 - 1,3-苯二酚 (QAMDHB) ,并研究了其与铜的显色反应 ,在 p H=2 .2的磷酸 -磷酸二氢钾缓冲介质中 ,溴化十六烷基三甲基胺 (CTMAB)存在下 ,QAMDHB与铜反应生成 2∶ 1稳定络合物 ,λmax=5 5 0 nm,ε=4 .84× 10 4L· mol-1· cm-1。铜含量在 0— 2 0μg/ 2 5 m L范围内符合比耳定律 ,方法用于环境水样中铜含量的测定 ,结果令人满意  相似文献   

5.
利用可调谐真空紫外同步辐射和分子束实验装置在8.0~15.5 eV的光子能量范围内,研究2-甲基-2-内烯-1-醇的光电离解离.测出母体离子和碎片离子:C_4H_8O~+、C_4H_7O~+、C_3H_5O~+、C_4H_7~+、C_4H_6~+、C_4H_5~+、C_2H_4O~+、C_2H_3O~+、C_3H_6~+、C_3H_5~+、C_3H_3~+、CH_3O~+和CHO~+的光电离效率曲线,并获得母体分子的电离能和碎片离子的实验出现势.在B3LYP/6-31+G(d,p)理论水平上,计算光电离过程中母体分子、过渡态和中间体的稳定结构.采用CCSD(T)/cc-pVTZ耦合簇方法计算零点能,得到母体电离能和碎片离子的出现势.通过实验和理论研究,提出2-甲基-2-丙烯-1-醇的光解离路径,分子内氢转移是其中大部分解离途径中的主要过程.  相似文献   

6.
1-(2-吡啶偶氮)-2-萘酚薄膜的非线性光学特性研究   总被引:5,自引:0,他引:5  
运用Z扫描方法研究了1-(2-吡啶偶氮)-2-萘酚薄膜的非线性光学特性。用皮秒脉冲激光测得在532 nm 处、光强较低时χ(3)R = 1.29×10- 9 esu, β= 42 cm /GW; 同时研究了不同光脉冲能量时的非线性吸收特性, 发现其非线性吸收随着光强的增大由反饱和吸收转为饱和吸收  相似文献   

7.
本文报告二十个题目化合物的80兆1H NMR谱。这些新合成的化合物均未见诸文献。利用偶合常数鉴定了β-内酰胺环的立体构型,并对图谱进行了解析,证明所合成的化合物均为顺式构型的β-内酰胺单环衍生物,同时讨论了溶剂和取代基对化学位移的影响。  相似文献   

8.
本文合成了2-(1,2,4-三唑-1-基)-2-(3’,4’-二苯基-噻唑-2’-烯基)苯乙酮,对其进行了元素分析,并研究了该化合物的IR、^1HNMR及MS等波谱性质,从而确定了其结构。  相似文献   

9.
2-(2’-羟基苯基)苯并咪唑(简称HBI)是一类具有激发态质子转移效应的有机分子。观测了HBI分子在甲苯、甲苯与乙醇混合及乙醇三种溶液的吸收光谱,发现其吸收光谱相类似。用317 nm光激发,观测其荧光光谱,在甲苯溶液中只观测到一个荧光带,其峰值位于470 nm;在甲苯与乙醇的混合溶液及乙醇溶液的荧光光谱中,都观测到两个荧光带,其峰值分别位于370和450 nm。根据激发态质子转移理论可知,470 nm的荧光带是由激发态质子转移生成的互变异构体,即HBI酮式构型分子的发射,峰值位于370 nm的荧光带是HBI稀醇式构型分子的发射。由于乙醇具有较大的极性,可与HBI分子相互作用形成分子间氢键,即生成溶剂化物。当溶剂化物被激发,在激发态发生激发态质子转移生成两性离子,两性离子发射荧光回到基态。因此,在极性溶剂中HBI发射峰值位于450 nm的荧光带应归于两性离子的发射。当用532 nm强光激发HBI溶液时,发现HBI分子在非极性溶剂中无双光子效应,而在极性溶剂中却存在双光子效应,表明HBI的溶剂化物具有双光子效应。  相似文献   

10.
2-(2-喹啉偶氮)-1,5-苯二酚光度法测定铜的研究   总被引:11,自引:2,他引:9  
合成了新试剂 2 - ( 2 -喹啉偶氮 ) - 1,5-苯二酚 ( QADHB) ,并研究了其与铜的显色反应 ,在溴化十六烷基三甲胺 ( CTMAB)存在下 ,p H=4 .0邻苯二甲酸氢钾缓冲介质中 ,QADHB与铜反应生成 2∶ 1稳定络合物 ,λmax=540 nm,ε=2 .12× 10 4 L·mol-1·cm-1。铜含量在 0— 30 μg/ 2 5m L内符合比耳定律 ,该方法用于环境样品中铜的测定 ,结果令人满意  相似文献   

11.
Novel amphiphilic comb-like polymers (CPASA), used as viscosifying and filtration loss additives for low-solid water-based drilling fluids under high temperature and salinity conditions, were prepared from acrylamide, sodium 4-styrenesulfonate, and allyl polyethylene glycol ether with toluylene-end groups via inverse microemulsion polymerization. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance (1H-NMR). The thermal stability, aqueous solution properties, and drilling fluid properties were evaluated. Results showed that the comb-like polymers exhibited dramatic enhancement in their thermal- and salt-resistant properties because of the steric hindrance and intermolecular associations of the side-chains. The rheological properties, filtration properties, and negative Zeta potentials of both fresh-water drilling fluid and saturated salt-water drilling fluid were greatly improved by the addition of CPASA before and after thermal aging tests, which were ascribed to the steric hindrance of its comb-like conformation, the strong electrical double layer force of clay particles, and the stable mud network formed by CPASA and clay particles in drilling fluid.  相似文献   

12.
In order to avoid their agglomeration and incompatibility with hydrophobic polystyrene substrate, magnesium hydroxide nanoparticles were encapsulated by surface-initiated in-situ polymerization of styrene. The process contained two steps: electrostatic adsorption of initiator and polymerization of monomer on the surface of magnesium hydroxide. It was found that high adsorption ratio in the electrostatic adsorption of initiator could be attained only in acidic region, and the adsorption belonged to typical physical process. Compared to traditional in-situ polymerization, higher grafting ratio was obtained in surface-initiated in-situ polymerization, which can be attributed to weaker steric hindrance. Both Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) indicated that polystyrene/magnesium hydroxide nanocomposite particles had been successfully prepared by surface-initiated in-situ polymerization. The resulting samples were also analyzed and characterized by means of contact angle testing, dispersibility evaluation and thermogravimetric analysis.  相似文献   

13.
A series of solution processible light-emitting copolymers composed of tetraalkoxy-phenylenevinylene (TALK-PPV) and dialkoxy-phenylenevinylene (DALK-PPV) has been synthesized using the Gilch polymerization route. Thermal, optical and electrochemical properties of the synthesized copolymers [poly(TALKPV-co-DALKPV)s] have been investigated and compared with those of each homopolymers, poly[2-(3,7-dimethyloctyloxy)-3,5,6-trimethoxy]-1,4-phenylenevinylene] (TALK-PPV) and poly[2-(3′,7′-dimethyloctyloxy)-5-methoxy-1,4-phenylenevinylene] (DALK-PPV). The synthesized copolymers showed a high molecular weight (Mn=∼2-3.0×105) and narrow polydispersity indices (∼3). Electroluminescent devices using the copolymers as the emissive layer have been fabricated with a configuration of ITO/PEDOT:PSS/polymers/Ca/Al. Interestingly the copolymer devices resulted in a more than 4-fold increase in device lifetime than the homopolymers, which might be due to the highly reduced steric hindrance of the polymer backbone by introducing DALKPV units between the adjacent highly alkoxylated TALKPV repeating units in the polymer backbone.  相似文献   

14.
Poly(2-ethynyl-N-hexylpyridinium bromide) and poly(2-ethynyl-N-hexylpyridinium iodide) were synthesized by the direct polymerization of 2-ethynylpyridine and the corresponding n-hexyl halides without any additional initiator or catalyst under mild reaction condition. The polymerization proceeded well to give high yield of polymer. The polymer structures were characterized to have the conjugated polymer backbone system having N-hexylpyridyl moieties. The photoluminescence spectra of poly(2-ethynyl-N-hexylpyridinium bromide) and poly(2-ethynyl-N-hexylpyridinium iodide) showed that the photoluminescence peaks are located at 603 and 611 nm corresponding to the photon energy of 2.06 and 2.03 eV, respectively. The electrochemical properties of the resulting polymers were also measured and discussed.  相似文献   

15.
Shukla  S.  Seal  S.  Vij  R.  Bandyopadhyay  S. 《Journal of nanoparticle research》2002,4(6):553-559
Nano-sized zirconia (ZrO2) powder is synthesized using sol-gel technique involving hydrolysis and condensation of zirconium(IV) n-propoxide in an alcohol solution, utilizing hydroxypropyl cellulose (HPC) polymer as a steric stabilizer. It is demonstrated that ZrO2 nanoparticle size can be reduced using high R-value (defined as the ratio of molar concentrations of water and alkoxide). It is also shown that ZrO2 nanoparticle size can be reduced further by synthesizing these particles in the presence of HPC polymer. The agglomeration tendency of ZrO2 nanoparticles is demonstrated to decrease due to the steric hindrance created by the adsorbed polymer. The nanocrystallite size and their 'hard-aggregates' formation tendency are observed to affect the high temperature metastable tetragonal phase stabilization at room temperature within ZrO2 particles.  相似文献   

16.
本文发展了一种对蛋白质具有吸附/释放功能的二元混合刷涂层(BBC)毛细管,并将其用于蛋白质的在线富集. 通过阳离子开环聚合可逆加成断裂链转移聚合,分别合成了末端为氨基的聚(2-甲基-2噁唑啉)(PMOXA-NH2)以及末端为巯基的聚丙烯酸(PAA-SH). 然后通过聚多巴胺黏合层将PMOXA-NH2和PAA-SH依次接枝到熔融硅毛细管内表面,制备出基于聚(2-甲基-2-噁唑啉)(PMOXA) 和聚丙烯酸(PAA)的BBC毛细管. 利用扫描电镜、X射线光电子能谱分析了在毛细管内表面或毛细管原材料上形成的PMOXA/PAA涂层的厚度及组成. 通过荧光显微镜研究了一定pH及离子强度(I)下,BBC毛细管对蛋白质的吸附/释放功能. 结果表明, pH=5.0 (I=10-5 mol/L)时,BBC毛细管可以吸附牛血清蛋白(BSA),而当pH=9.0 (I=10-1 mol/L)时,吸附的BSA可被释放出来. 将这种具有蛋白质吸附/释放功能的涂层管用于毛细管电泳在线富集BSA,以提高BSA的检测灵敏度. 结果表明,在最佳条件下,BSA的灵敏度增强因子超过了5000.  相似文献   

17.
Pickering emulsion polymerization has been employed for the Ultrasonic assisted-micro solid phase extraction (UA-µSPE) of ultra trace arsenic species by a new magnetic ion imprinted polymer (MIIP) prior to hydride generation atomic absorption spectrometry. 2-acetyl benzofuran thiosemicarbazone (2-ABT) as a new chelating agent and core- shell hydrophobic magnetic nanoparticles was synthesized and the polymerization was carried out at the presence of arsenic – ligand complex, crosslinker, monomer, initiator, stabilizing agent and water-oil emulsion magnetic carrier. In second step, the nanoparticles and polymers were characterized. The analytical parameters such as pH, amount of polymer and ultrasonic time were selected and optimozed by Plackett–Burman and Box–Behnken designs respectively. Linear dynamic range, detection limit and relative standard deviation were 0.01–85.000 µg·L−l, 0.003 µg·L−l, and 3.21%, respectively. The proposed preconcentration procedure was successfully applied to the determination of arsenic ion in a wide range of food samples with different and complex matrixes.  相似文献   

18.
Stable dispersion of titania nanoparticles in organic solvents are obtained by grafting poly(methyl methacrylate) layer on to the surface. Titania nanoparticles are synthesized through the hydrolysis of titanium (IV) isopropoxide. The average size of the titania particles is found to be 15 ± 2 nm. The polymer layer was introduced onto the surface by immobilizing the initiating moiety. Azo initiator moiety required for surface-initiated conventional free radical polymerization and a tertiary bromide initiator moiety required for ATRP are attached covalently to the titania nanoparticulate surface through the surface hydroxyl groups. The “encapsulation” of PMMA layer results in the steric stabilization of the titania nanoparticles. Another important finding is that it is possible to grow polymer layer in a controlled fashion.  相似文献   

19.
1-acryloylpyrrolidine-2-carboxylic acid (APCA) monomer was copolymerized with acrylonitrile (AN) by aqueous suspension polymerization. High molecular weight (HMW) copolymers of AN and APCA [poly(AN-co-APCA)] with different copolymer composition were successfully prepared by employing azobisisobutyronitrile (AIBN) as initiator and polyvinyl alcohol (PVA) as dispersant in a H2O/N,N-dimethylformamide (DMF) mixture at 60°C. The PAN homopolymer and copolymers were characterized by elemental analysis (EA), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The EA results indicated that the content of oxygen increased significantly in PAN copolymers with increasing APCA content. The APCA copolymer composition calculated from the EA was higher than that from 1H NMR spectra. The FTIR spectra of PAN and poly(AN-co-APCA) with different monomer ratios confirmed that the contents of APCA units in the copolymer chains increased with increasing APCA content in the feed. The DSC exotherms revealed that copolymerization with APCA could slow the rate of the exothermic reactions during the heat-treatment processes. The XRD results indicated that the PAN homopolymer and copolymers poorly crystallized and the crystallinity decreased with increasing APCA contents.  相似文献   

20.
A noble self-dopable conjugated polybetaine, poly[2-ethynyl-N-(4-sulfobutyl)pyridinium betaine] (PESPB) was synthesized by the activated polymerization of 2-ethynylpyridine with 1,4-butanesultone without any additional initiator or catalyst. This polymerization proceeded at the condition of high temperature (130 °C). The polymer yield and inherent viscosity were 82% and 0.13 dl/g, respectively. The chemical structure of PESPB was identified by various instrumental methods to have a conjugated ionic polymer bearing the sulfobetaine moieties. This poly(sulfobetaine) was found to be more soluble in salt solution than in salt-free solution. The photoluminescence peak is located at 530 nm corresponding to the photon energy of 2.34 eV. The photoluminescence intensity was increased as the temperature is increased. At 1 kHz and room temperature, the dielectric constant and electrical conductivity of PESPB were 5.7 and 3.5 × 10−9 S/cm, respectively.  相似文献   

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