红外光谱法研究仲辛醇氧化反应

用红外光谱法研究了浓硝酸氧化仲辛醇合成己酸的反应历程。考察了中间产物硝酸酯，亚硝酸酯，酮类化合物，硝基化合物，有机腈等成分随硝酸用量的变化规律，并对其反应机理进行了探讨。     

L-苏糖酸及其金属化合物的红外光谱研究

制备了高纯度的L-苏糖酸及其与钙、镁、锰、钴、镍和锌的化合物,用化学分析和元素分析确定了它们的组成;通过红外光谱分析研究,确定金属离子与L-苏糖酸的羰基氧配位,同时与羧基脱质子配位,而醇羟基质子不解离,金属离子为sp~3杂化,配位数为4。     

草酸在铅电极上电催化还原过程的in situ FTIRS研究

采用电化学原位傅里叶变换红外反射光谱(electrochemical in situ fourier transform infrared reflection spectroscopy,in situ FTIRS)研究了草酸在铅电极上电催化还原过程。 多步电位阶跃FTIRS(MSFTIRS)和时间分辨FTIRS(TRFTIRS)的结果表明：当研究电位为-0.70 V(vs. SCE)时,即可明显检测到乙醛酸生成;研究电位为-0.85 V时,电极表面累积生成乙醛酸的量达到最大值。 随着电位的负移,生成的乙醛酸的量减少。 同时在-0.95 V时即可明显检测到乙醛酸进一步被还原,生成的乙醇酸在1 093 cm-1 附近为—CH₂OH的CO伸缩振动吸收。 当研究电位为-1.50 V时,电极表面的乙醛酸几乎都被还原成乙醇酸。 另外,随着电位的负移,并没有检测到其他新物种的出现,表明乙醇酸在电极表面不会进一步发生还原反应。 研究电位为-0.75 V的原位时间分辨红外反射光谱显示反应产物乙醛酸在1 750 cm-1 左右CO的伸缩振动吸收谱峰的左右积分强度随时间线性增加;而研究电位在-1.60 V原位时间分辨红外反射光谱还观察到乙醇酸在1 093 cm-1附近—CH₂OH的C—O伸缩振动吸收。 电化学原位红外反射光谱技术有利于对反应中各物种官能团振动吸收的检测,为草酸电催化还原反应机理提供直接实验依据。     

A robust method for the synthesis of colloidal PbS nanosheets

In the synthesis of colloidal PbS nanosheets, acetic acid – either injected externally or produced during the reaction – has a significant effect on the growth of the nanosheets. When the acetic acid to lead molar ratio is above 1:8, no nanosheets are observed in the product. By replacing lead acetate with lead oxide to prepare the lead precursor for the reaction, the effect of acetic acid is avoided, resulting in a robust synthesis with nearly 100% success rate. In the new synthesis, the purity of trioctylphosphine (the co‐solvent for sulfur precursor) has no significant effect on the formation of nanosheets. Thickness tunability is achieved in the acetate‐free synthesis by tuning the reaction temperature. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

基于固体核磁共振技术的固体酸结构、酸性及活性分析

固体酸是工业烃转化和生物质精炼中应用最广泛的非均相催化剂之一，了解它们的局部结构和酸性等性质有利于合理设计高效绿色固体酸催化剂，从而提高目标反应的活性和稳定性.近年来，固体核磁共振波谱在定性和定量表征固体酸的局部结构和酸性方面已显示出巨大的应用潜力，甚至可作为一种标准方法.二维固体核磁共振波谱的应用可以进一步揭示固体酸表面位点的结构对称性和不同位点的空间构效关系，从而加深对“催化剂结构-酸性-活性关系”的理解.在这篇综述中，我们总结了用于固体酸表征的固体核磁共振波谱方法和常规实验操作流程，并着重阐述了在使用和不使用探针分子的情况下，固体核磁共振波谱应用于固体酸局部结构和酸性性质研究的进展.     

Spectrophotometric Determination of Enalapril Maleate and Ramipril in Dosage Forms

Three sensitive and accurate spectrophotometric methods have been developed for the assay of enalapril maleate and ramipril, each in its dosage forms. These methods depend on the reaction of the drugs with p-chloranilic acid, the reaction with picric acid, and the ion-pair salt formation with bromocresol green. The proposed methods have been applied to the analysis of these drugs in their commercial tablets. The results obtained were precise and accurate.     

重新审视桥式吸附甲酸根在铂电极上电催化氧化甲酸过程中的作用 (cited: 2)

基于以前报道的电化学原位ATR-FTIRS数据(Langmuir 22,10399 (2006)和Angewa. Chem. Int. Ed., 50,1159 (2011)),详细讨论了甲酸在铂电极上电催化氧化机理及动力学过程．提出了直接反应路径的动力学模型,即甲酸吸附(同时C-H键活化)作为此反应的决速步骤,此反应路径贡献甲酸氧化反应的大部分电流．该动力学模型可以很好地拟合在无CO毒化影响和浓度在0.1 mol/L以下的红外光谱结果．这种机理预测了甲酸氧化直接途径可能只需要一个Pt原子作为反应位点,甲酸根阻碍活性位点,并非为反应中间物．另外还详细检验了之前其他小组曾提出的甲酸根途径(一级或二级反应)为甲酸氧化直接途径,并指出了引起分歧的原因．     

The use of acids,niobium oxide,and zeolite catalysts for esterification reactions

We have evaluated the influence of alcohol/fatty acid molar ratio (methanol or ethanol), water and catalyst concentrations and temperature by the esterification of palm fatty acids by heterogeneous acid catalysts (varying types, forms, and particle size). Polynaphtalene sulfonic acid (PSA) and niobium oxide (Nb₂O₅) presented better performance than zeolite catalysts. Reaction with methanol presented higher conversion than with ethanol. The experimental design showed that the most relevant variable is the catalyst concentration and all interactions become important in process. A heterogeneous kinetic model was proposed and applied to experimental data. One of the models was adequate for methanol reaction, whereas the homogeneous model was more appropriate for ethanol reaction. Copyright © 2009 John Wiley & Sons, Ltd.     

石墨烯固体酸催化转化葡萄糖为化学品

利用氢化钠和丙磺酸内酯合成出了磺化石墨烯催化剂,采用XPS、FT-IR、TEM等方法对其进行了表征,并且对此催化剂催化葡萄糖的转化反应进行了研究．探究此催化剂在纯水中、没有添加任何有机溶剂下催化转化葡萄糖制备高附加值化学品方面的催化活性,在最优的反应条件下, 5-羟甲基糠醛(HMF)最高产率可达28.8%,产物甲酸、乳酸和HMF的总产率可达51.94%．经过5次催化反应,催化剂仍表现出相对高的催化活性,三种产物的产率依然较高,表明此种固体酸催化剂有很好的热稳定性．     

停流荧光法研究牛血清白蛋白和叶酸反应动力学

叶酸属于B族维生素,作为生物体内转移一碳单位酶系中的辅酶,与其他维生素相互作用,共同维持体内红细胞的稳定,对氨基酸之间的转化、细胞的分裂生长,蛋白质合成的反应都有重要意义。药物半衰期、峰浓度和反应速度常数是研究药代动力学的重要参数,实验运用荧光分光光度计和停流光谱分析仪研究了仿生环境下牛血清白蛋白和叶酸反应的动力学参数,为叶酸相关的药物代谢参数提供参考。结果表明：利用Stern-Volmer方程处理荧光猝灭实验数据,得到25, 30和37 ℃下叶酸对牛血清白蛋白内源荧光的静态猝灭常数分别为2.455×1010,4.900×1010和6.427×1010 L·mol-1·s-1;动力学反应速率常数的计算结果表明不同温度、pH值和缓冲介质下BSA和叶酸反应的速率常数都大于100 mol·L-1·s-1,阐明了BSA与叶酸之间的猝灭机理是通过形成复合物的静态猝灭过程;生理温度下,牛血清白蛋白浓度与其初始浓度满足二级反应公式,相关系数为0.998 7,药代半衰期t_1/2为0.059 s;反应的表观速率常数随着叶酸浓度的增加呈线性增加趋势,且叶酸催化牛血清白蛋白荧光猝灭的速率常数k_cat=3.174×105 mol·L-1·s-1。此外还测定了不同缓冲介质下牛血清白蛋白与叶酸相互作用的表观速率常数和反应速率常数,以此来探讨生理介质对于二者反应的影响,为确定临床用药方案、预测药物的疗效和毒性以及合理用药有着重要意义。     

小分子有机酸改性尿素的多谱学分子结构表征

尿素是我国主要的氮肥品种,但其活性高,在土壤中水解后极易通过挥发和淋洗损失,利用率低,造成养分资源浪费并污染环境。使用有机酸对尿素进行改性可以延缓尿素分解,提高尿素利用率,但有机酸与尿素的结合方式及其增效机理尚不明确。研究中选取柠檬酸和水杨酸两种小分子有机酸作为添加剂,分别加入到熔融尿素中,获得柠檬酸尿素与水杨酸尿素。利用傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）分析材料的化学结构,利用液相色谱-质谱联用（LC-MS）研究材料的物质组成及相对分子质量,尝试通过以上多谱学的分析方法,明晰两种有机酸与尿素的结合方式。结果表明,柠檬酸和水杨酸与尿素结合后,FTIR在3 348 cm-1处产生了加强的伯胺振动峰,推测小分子有机酸与尿素在伯胺处发生了反应。XPS C(1s)和N(1s)图谱分别出现新的碳结构（-CX）和新的氮结构（-NX）,降低了柠檬酸/水杨酸中原有羧基碳结构和尿素中酰胺基氮结构的相对含量,O(1s)图谱出现C-OH化学键断裂,表明,柠檬酸/水杨酸的羧基与尿素的酰胺基相互作用生成了新的物质。LC-MS分析发现柠檬酸尿素/水杨酸尿素中的新物质可能是柠檬酸/水杨酸的羧基与尿素的酰胺基发生脱水反应,生成含有O═CNHC(O)NH₂结构的物质。因此,利用光谱分析等手段明晰了有机酸与尿素的结合方式与结合产物特征,为有机高分子与尿素反应机理的研究提供了理论依据,为后续高效肥料增效剂的筛选提供了方向。     

Pseudo‐homogeneous kinetic model for esterification of acetic acid with propanol isomers over dodecatungstophosphoric acid supported on montmorillonite k10

Esterification of acetic acid with propanol isomers such as isopropanol and n‐propanol was carried out over dodecatungstophosphoric acid (DTPA), dodecamolybdophosphoric acid ammonium salt hydrate, and sodium tungstate hydrated purified supported on montmorillonite K10, which were characterized by powder X‐ray diffraction, Brunauer–Emmett–Teller, and temperature programmed ammonia desorption. A pseudo‐homogeneous (P‐H) kinetic model was established for esterification of acetic acid with propanol isomers over DTPA supported on montmorillonite K10. Effects of various parameters such as reaction time, speed of agitation, particle size, temperature, percent catalyst loading, molar ratio and mixture of propanol isomer were investigated in detail. The 20% (w/w) DTPA/K10 was found to be an optimum solid catalyst with 82% n‐propanol and 53% isopropanol conversion with 100% selectivity toward propyl acetate. The 20% (w/w) DTPA/K10 catalyst was found to be reusable for three cycles. The reaction follows second‐order kinetics with activation energies of 25.53 kJ mol^?1 and 28.15 kJ mol^?1 for isopropanol and n‐propanol, respectively. Pseudo‐homogeneous kinetic model fitted with R² value of trend line 0.999. This implies that esterification reaction is kinetically controlled owing to high activation energy. Copyright © 2013 John Wiley & Sons, Ltd.     

Ultrasound enhanced butyric acid-lauric acid designer lipid synthesis: Based on artificial neural network and changes in enzymatic structure

Ultrasound is a green technology for intensifying enzymatic reactions. In this study, an ultrasonic water bath with equipment parameters of 28 kHz, 1750.1 W/m², 60% duty cycle was used to assist the synthesis of butyric acid-lauric acid designer lipid (BLDL), which was catalyzed by Lipozyme 435. A convincing three-layer feed-forward artificial neural network (ANN) model was established (R² = 0.949, RMSE = 4.759, ADD = 7.329) to accurately predict the optimal parameters combination, which was described as 13.72 mL reaction volume, 15.49% enzyme loading, 0.253 substrate molar ratio (tributyrin/lauric acid), 56.58 °C reaction temperature and 120 min reaction time. The ultrasonic assistance increased actual butyric acid conversion rate by 11.38%, and also enhanced the consumption rate of tributyrin and lauric acid during the reaction. Meanwhile, the esterification activity of Lipozyme 435 was enhanced and its effectiveness up to 6 cycles. Structurally, ultrasound assistance significantly disrupted the secondary structure of the Lipozyme 435: reduced the content of α-helices, increased the content of β-sheet and β-turn. In addition, sonication caused an increase in crevice and micro-damage on the surface of the immobilized enzyme. In conclusion, low-intensity ultrasound at 28 kHz improved the synthesis efficiency of BLDL, which was scientifically predicted by ANN model, and the change of enzyme structure may be the vital reason for ultrasound enhanced reaction. However, the effect of ultrasound on immobilized enzymes’ activity needs to be further explored.     

Quantum chemical study on gas phase decomposition of ferulic acid

Ferulic acid, representing phenolic fraction of bio-oil, is considered to be a model compound in this study for its decomposition into various end products such as ethylbenzene, eugenol, cis-isoeugenol, vanillin, 4-ethylguaiacol, guaiacol, and acetovanillone using density functional theory approach. Results of bond dissociation energies indicate that cleavage of methyl group from ferulic acid is the lowest energy-demanding bond scission amongst all 14 bond cleavages. Primary end product by decomposition of ferulic acid is found to be ethylbenzene and its production occurs through the formation of intermediate products such as 4-hydroxycinnamic acid, cinnamic acid and styrene. Demethoxylation of ferulic acid gives rise to the production of 4-hydroxycinnamic acid which further undergoes the formation of cinnamic acid by dehydroxylation reaction route. The formation of cinnamic acid in this study is carried out using three reaction schemes 1–3 and its further reduction to ethylbenzene is performed using two reaction possibilities. Finally, favourable pathway is found to be decarboxylation of cinnamic acid to produce vinylbenzene followed by the production of ethylbenzene using hydrogenation of C=C chain double bond. Furthermore, thermochemistry of each reaction scheme is performed at atmospheric pressure and at a wide range of temperature of 598–898 K.     

银改性磷钨酸催化制备生物柴油工艺研究

本文以硝酸银和磷钨酸为原料制备了系列银改性磷钨酸催化剂Ag_xH_3-xPW₁₂O₄₀（x=1、2、3,x表示AgNO₃与磷钨酸的物质的量之比）,并利用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、热重量分析-导数热重量分析（TGA-DTG）和固体核磁共振结合探针分子（³¹P-TMPO MAS-NMR）技术对它们的结构、稳定性及酸性进行了表征;同时考察了甲醇/大豆油的物质的量之比、催化剂用量、反应温度和反应时间等因素对磷钨酸银催化酯交换反应的影响.研究结果表明,Ag₂HPW₁₂O₄₀催化剂具有最好的催化酯交换反应活性和重复使用性能,其结构中的Brønsted酸中心与Lewis酸中心之间的协同效应是使其具有高催化性能的原因.以Ag₂HPW₁₂O₄₀为催化剂,在甲醇/大豆油的物质的量之比为32/1、催化剂用量为6 wt.%、反应温度为150℃、反应时间为20 h条件下,生物柴油产率可达96.4%.     

荧光猝灭法对肉桂酸与人血清白蛋白间的相互作用的研究

白蛋白是血液循环系统中最丰富的一种蛋白质,能与许多物质结合,并起着运输蛋白的作用。文章利用荧光光谱法研究了中药有效成分肉桂酸与人血清蛋白间的非共价结合特性。研究表明,在pH7.4作用液、286nm激发波长条件下,肉桂酸对人血清白蛋白的荧光发射有较强猝灭作用。当作用温度为37和47℃时,肉桂酸与人血清蛋白间的结合常数K分别为1.2767×103和3.4041×103L.mol-1,结合位点数n分别为0.7586和0.8356,表明温度升高有利于两者的结合;同时,根据不同作用温度时非共价结合复合物的热力学参数变化,证明肉桂酸与人血清白蛋白分子间的结合力主要是疏水作用。研究结果为进一步研究肉桂酸的药理作用,尤其是对血浆蛋白构像的影响提供了重要信息。     

聚乙烯醇与氨基酸接枝共聚物的合成及光谱研究

本文致力于氨基酸类高分子药物的合成、表征。研究目的是研制一种氨基酸类高分子药物用于临床治疗；研究方法是将氨基酸与选定的高分子化合物进行高分子化学反应，联结到高分子链上；研究结果是合成了聚乙烯醇与氨基酸（甘氨酸、丙氨酸）的共聚物，用红外光谱、核磁共振谱对共聚物进行了分析和表征，并通过谱图对氨基酸的转化率进行了讨论，结果证明产物符号要求，且甘氨酸比丙氨酸的转化率高。     

Dissolved organic matter inhibition of sonochemical degradation of aqueous polycyclic aromatic hydrocarbons

Sonochemical degradation of aqueous polycyclic aromatic hydrocarbons (PAHs) was found to be rapid in the absence of other dissolved compounds (k = 0.006-0.015 s-1). In the presence of 20 mg Cl-1 fulvic acid, first-order PAH degradation rate constants decreased from 2.3- to 3.7-fold. Similar results were obtained with added benzoic acid, a crude analog for fulvic acid. In natural waters, PAH degradation was almost completely inhibited. Analysis of the kinetic behavior and reaction products indicates that PAHs are most likely degraded through a radical cation mechanism. Hydroxyl radical appeared to play an insignificant role in the degradation. Inhibited degradation was probably the result of either altered cavitation processes or isolation of the PAH away from cavitation sites.     

硬脂酸与戊胺的微波反应

本文利用红外光谱对硬脂酸和戊胺的微波反应进行了研究。结果表明：硬脂酸与戊胺等摩尔充分混合后,生成硬脂酸戊铵盐,体系中残存的少量硬脂酸与其戊铵盐形成酸盐结构。在微波辐射下,硬脂酸戊铵盐有明显的分解反应,并可进一步脱水生成酰胺。微波作用于反应物,能使化学反应更快速地进行或向更深处进行,微波反应可调节产物的结构。     

Vibrational study on the interactions between yak keratin fibres and glyoxylic acid

Raman and IR spectroscopy were used to investigate the changes induced in yak hair keratin by the straightening treatment based on glyoxylic acid. The amino acidic residues that appeared involved in the reaction with glyoxylic acid were serine and lysine; the involvement of the latter was deduced by the spectroscopic detection of iminic species, resulting from the reaction between the aminic group of lysine and the carbonyl group of glyoxylic acid. The reaction with glyoxylic acid induced conformational rearrangements that mainly involved the fibre bulk rather than the cuticle. Changes in the average tyrosine environment and its hydrogen‐bonding state were detected: at increasing glyoxylic acid incorporation, the tyrosine residues appeared more exposed, probably because of H‐bond interactions with the COOH group. The distribution of the disulfide bridge conformation was also affected, although no cleavage of the S–S bond was detected, in agreement with the shiny and healthy appearance of the fibres. Copyright © 2014 John Wiley & Sons, Ltd.