丁酸戊酯在用H2SO4改性的H-β沸石上的催化合成

以H2SO4改性的H-β沸石作催化剂合成了丁酸戊酯，考察了合成条件对正丁酸与正戊醇酯化反应的影响。适宜的反应条件为：催化剂用量8．8g／mol正丁酸，mol正戊酸：mol正戊醇=1：1．2，带水剂环己烷用量18mL／mol正丁酸，反应温度157℃～165℃，反应时间3h。在此反应条件下正丁酸的转化率在83％以上。该催化剂能够重复使用，所得正丁酸的转化率与新鲜催化剂的几乎相同。     

用β沸石分子筛作催化剂液-固相合成丁酸戊酯的研究

用β沸石分子筛作催化剂，对正丁酸与正戊醇的液-固相酯化反应进行了研究，考察了催化剂用量、β沸石中阳离子的类型、醇酸摩尔比、反应时间、带水剂环己烷的用量和催化剂活化时间对正丁酸转化率及丁酸戊酯产率的影响，提出了无催化剂及以Al-β沸石分子筛为催化剂时的酯化反应动力学模型。     

醋酸丁酸纤维素合成研究

以纤维素为原料,乙酐、正丁酸为酰化剂,浓硫酸为催化剂,合成了醋酸丁酸纤维素。FT-IR分析证实了酯化产物的生成。采用冰醋酸、NaOH、浓H2SO4、乙二胺等前处理方法对纤维素进行预处理,应用XRD和粘度法表征了产物的结晶结构和聚合度,结果表明冰醋酸处理法较好。适宜的合成条件为:纤维素10g、催化剂用量0.25mL、乙酐/正丁酸摩尔比1∶5、酯化反应温度70℃、酯化反应时间1h。     

对甲苯磺酸催化合成丁酸丁酯的研究

丁酸丁酯是无色至淡黄色透明油状液体,有成熟香蕉似水果香气.稀释时为菠萝和朗姆酒香气及稀奶油滋味.天然品存在于苹果、香蕉、葡萄、梨、草莓、李、西番果等中.主要用以配制苹果、香蕉、梨和奶油等型香精,是我国GB2760-86规定允许使用的食用香料;也可用于有机合成和用作溶剂.通常它是在硫酸催化下由丁酸和正丁醇酯化反应而得[1-2],硫酸虽活性高,价廉,但选择性差,产品质量不好,设备腐蚀严重,同时产生大量废液,污染环境.因此人们寻求更优良的催化剂来代替硫酸,已发现强酸性阳离子交换树脂、磺酸树脂、固体超强酸、杂多酸以及过渡金属硫酸铜、氯化铁等均可作为酯化反应的催化剂[3-8].但用固体酸催化合成丁酸丁酯至今未见报道.对甲苯磺酸是一种强有机酸,无氧化性,无碳化作用,作为酯化反应的催化剂时,具有活性高,选择性好,产品纯度高,不腐蚀设备,减少污染等优点[9-10].本文利用对甲苯磺酸作催化剂合成丁酸丁酯,讨论了影响反应的因素,在适当的合成条件下,酯化率可达97.8%.     

氨磺酸催化合成丁酸丁酯的研究

以氨磺酸为催化剂催化合成了丁酸酯,确定了酯优化条件。实验结果表明：在酸用量为０．２ｍｏｌ,醇酸摩尔比值为１．８,催化用量１．０ｇ,带水剂甲苯１５ｍＬ,反应时间２．０ｈ,反应温度１１０℃－１３０℃的最佳反应条件下,酯化率为９８．２％。     

甲烷磺酸铜催化合成丁酸酯的性能

丁酸异戊酯;酯化反应;催化活性;甲烷磺酸铜催化合成丁酸酯的性能     

环境友好催化剂TiSiW12O40/TiO2的制备及其催化性能研究

制备了新型固载杂多酸盐TiSiW12O40/TiO2环境友好催化剂,并以丁酸丁酯的合成作为探针反应,系统考察了原料H4SiW12O40@xH2O与TiO2摩尔比、焙烧温度、焙烧时间等制备条件对TiSiW12O40/TiO2催化活性的影响.实验表明:制备催化剂的适宜条件为原料H4SiW12O40@xH2O与TiO2摩尔比为0.47,焙烧温度为350℃,焙烧时间为3.0 h.利用该条件下制备的催化剂TiSiW12O40/TiO2合成丁酸丁酯,正丁醇与正丁酸的投料摩尔比n(醇):n(酸)=1.3:1,催化剂的用量占反应物总投料质量的1.3%,反应时间为1 h,丁酸丁酯的产率为97.2%.该催化剂TiSiW12O40/TiO2用于制备其它丁酸酯类(如乙酯、丙酯、戊酯、异戊酯)时同样取得了好的结果.     

纳米复合锆基固体超强酸的制备及其催化酯化反应

采用改性技术和浸渍—沉淀法制备出纳米固体超强酸催化剂S2O82-/ZrO2-Al2O3。通过正交试验获得催化剂制备的最佳条件,即ω(Al2O3)为2.0%,-15℃陈化24h,浸渍液(NH4)2S2O8浓度为0.8mol/L,焙烧温度为650℃,焙烧时间为3h。用XRD、TEM、BET、TG-DTG和化学分析等手段分析了S2O82-/ZrO2-Al2O3的晶化过程、比表面积、含硫量和热稳定性,分析结果表明这四个方面对催化剂的酸性有较大影响。500~650℃焙烧温度下制备的催化剂属纳米材料(<41nm),有较大比表面积和较好的热稳定性。以优化的催化剂S2O82-/ZrO2-Al2O3用于催化合成丁酸异丁酯的最佳条件为:n(异丁醇):n(丁酸)=1.8:1.0,催化剂用量为1.0g(以0.3mol丁酸为准),脱水剂环己烷用量为10mL,反应时间为3.0h,催化剂重复使用8次后酯化率仍在90%以上,该催化剂具有催化活性高、不污染环境、可重复使用等特点。     

微波辅助合成邻羟基苯丁酮

利用微波辅助,以丁酸苯酯为原料,经Fries重排制备了邻羟基苯丁酮.通过单因素实验考察了反应时间、催化剂用量及反应温度对收率的影响,正交实验确定了最优工艺条件.结果表明,当n(催化剂):n(丁酸苯酯)=1.6,反应温度120℃,反应时间8 min时,丁酸苯酯完全转化,邻羟基苯丁酮收率45.0%.     

SO42-/SnO2-硅藻土型固体酸的制备及其对正丁酸与异戊醇的催化酯化

采用质量比为1∶3的SnCl₄·5H₂O和硅藻土制备的硅藻土Sn(OH)₄溶胶,70 ℃老化12 h,90 ℃干燥12 h、3.0 mol/L硫酸浸渍3 h、550 ℃焙烧3.5 h,制备了SO₄^2-/SnO₂硅藻土型固体酸催化剂。 利用IR、 XRD、TG测试技术表征了催化剂的理化性质。 用于催化正丁酸与异戊醇的酯化反应,当n（异戊醇）∶n（正丁酸）=1.4∶1、催化剂用量为反应物总质量的2.5%、10 mL苯、反应时间70 min时,酯收率为97.7％。 结果表明,该催化剂兼具多元氧化物型固体酸和硫酸酸化改性天然粘土固体酸催化剂的优点,催化活性高,成本低廉、制备方法简单并可适当回收循环使用。     

Synthesis of isoamyl laurate and isoamyl stearate in supercritical carbon dioxide

The synthesis of isoamyl laurate and isoamyl stearate was studied in supercritical carbon dioxide with three lipases, Novozym 435, Lipolase 100T, and Candida rugosa. The maximum conversion of 37% and 53%, respectively for isoamyl laurate and isoamyl stearate was obtained when Novozym 435 was used. The effect of various parameters such as molar ratio of alcohol to acid, presence of water, time and temperature was investigated. An optimum temperature of 40–45°C was observed for all reactions. The kinetics of reactions was fast and equilibrium was achieved in 2–3 h. Although the presence of excess alcohol did not reduce conversion, excess water reduced conversion significantly.     

快速测定啤酒中异戊醇含量

采用气相色谱-质谱联用法,配合溶剂延迟并选择适当的质谱扫描范围以及Postrun迅速升温、迅速加大载气流量,以直接进样的方法快速测定了啤酒中异戊醇的含量。通过比较内标法和外标法对定量准确性和速度的影响,找到一种简单快速的对啤酒中异戊醇定量的方法(用内标法每个样品只用4min),并且测定了市售17种啤酒中异戊醇的含量。     

反胶束体系中脂肪酶催化合成异丁酸异戊酯

报道了在CTAB/正己烷和AOT/正己烷反胶束体系中,CCL脂肪酶催化合成异丁酸异戊酯的新方法.考察了水含量w₀、底物与酶的比例、缓冲溶液pH值以及温度等因素对脂肪酶催化酯合成反应的影响.研究结果表明,两种反胶束体系均为合成异丁酸异戊酯提供了较为合适的微环境,所选定的脂肪酶在CTAB和AOT反胶束中的活性分别是有机溶剂中反应活性的6倍和4倍.     

Potentialities of two solventless extraction approaches—Stir bar sorptive extraction and headspace solid-phase microextraction for determination of higher alcohol acetates, isoamyl esters and ethyl esters in wines

A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography-quadrupole mass spectrometry (SBSE-LD/LVI-GC-qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in terms of extraction time, influence of ethanol in the matrix, liquid desorption (LD) conditions and instrumental settings. Higher extraction efficiency was obtained using 60 min of extraction time, 10% ethanol content, n-pentane as desorption solvent, 15 min for the back-extraction period, 10 mL min⁻¹ for the solvent vent flow rate and 10 °C for the inlet temperature. For HS-SPME, the fibre coated with 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) afforded highest extraction efficiency, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 25 °C for 60 min under continuous stirring in the presence of sodium chloride (10% (w/v)). Both methodologies showed good linearity over the concentration range tested, with correlation coefficients higher than 0.984 for HS-SPME and 0.982 for SBES-LD approach, for all analytes. A good reproducibility was attained and low detection limits were achieved using both SBSE-LD (0.03-28.96 μg L⁻¹) and HS-SPME (0.02-20.29 μg L⁻¹) methodologies. The quantification limits for SBSE-LD approach ranging from 0.11 to 96.56 μg L⁻and from 0.06 to 67.63 μg L⁻¹ for HS-SPME. Using the HS-SPME approach an average recovery of about 70% was obtained whilst by using SBSE-LD obtained average recovery were close to 80%. The analytical and procedural advantages and disadvantages of these two methods have been compared.Both analytical methods were used to determine the HAA, IsoE and EE fatty acids content in “Terras Madeirenses” table wines. A total of 16 esters were identified and quantified from the wine extracts by HS-SPME whereas by SBSE-LD technique were found 25 esters which include 2 higher alcohol acetates, 4 isoamyl esters and 19 ethyl esters of fatty acids. Generally SBSE-LD provided higher sensitivity with decreased analysis time.     

Contributions to the Chemistry of the Binary Compounds of the Transition Elements

Phase and structural relationships of the sulfur, selenium, and tellurium compounds of the 4d and 5d transition elements of groups IV to VII of the periodic system are discussed. Homologous elements behave very similarly with respect to the chalcogens, and this is particularly the case for niobium and tantalum, and for molybdenum and tungsten. However, zirconium, niobium, and molybdenum have a greater tendency towards formation of chalcogen-poor phases than their homologues hafnium, tantalum, and tungsten. Subchalcogenides are known only for zirconium and niobium. The number of phases and the tendency towards formation of solid solutions are considerably smaller among the tellurides than among the sulfides and selenides. The crystal structures of the telluride phases also differ from those of the sulfide and selenide phases of analogous composition. In addition, a review of the phase and structural relationships of the arsenic and antimony compounds of the 4d and 5d transition elements of groups V to VII is given.     

Semiconductor quantum dots and metal nanoparticles: syntheses,optical properties,and biological applications

We review the syntheses, optical properties, and biological applications of cadmium selenide (CdSe) and cadmium selenide–zinc sulfide (CdSe–ZnS) quantum dots (QDs) and gold (Au) and silver (Ag) nanoparticles (NPs). Specifically, we selected the syntheses of QDs and Au and Ag NPs in aqueous and organic phases, size- and shape-dependent photoluminescence (PL) of QDs and plasmon of metal NPs, and their bioimaging applications. The PL properties of QDs are discussed with reference to their band gap structure and various electronic transitions, relations of PL and photoactivated PL with surface defects, and blinking of single QDs. Optical properties of Ag and Au NPs are discussed with reference to their size- and shape-dependent surface plasmon bands, electron dynamics and relaxation, and surface-enhanced Raman scattering (SERS). The bioimaging applications are discussed with reference to in vitro and in vivo imaging of live cells, and in vivo imaging of cancers, tumor vasculature, and lymph nodes. Other aspects of the review are in vivo deep tissue imaging, multiphoton excitation, NIR fluorescence and SERS imaging, and toxic effects of NPs and their clearance from the body. Figure Semiconductor quantum dots and metal nanoparticles have extensive applications, e.g., in vitro and in vivo bioimaging Tamitake Itoh and Abdulaziz Anas contributed equally to this article.     

Simultaneous analysis of serotonin, melatonin, piceid and resveratrol in fruits using liquid chromatography tandem mass spectrometry

An analytical method was developed for the simultaneous quantification of serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol using reversed-phase high performance liquid chromatography coupled to mass spectrometry (HPLC-MS) with electrospray ionization (ESI) in both positive and negative ionization modes. HPLC optimal analytical separation was achieved using a mixture of acetonitrile and water with 0.1% formic acid as the mobile phase in linear gradient elution. The mass spectrometry parameters were optimized for reliable quantification and the enhanced selectivity and sensitivity selected reaction monitoring mode (SRM) was applied. For extraction, the direct analysis of initial methanol extracts was compared with further ethyl acetate extraction. In order to demonstrate the applicability of this analytical method, serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol from 24 kinds of commonly consumed fruits were quantified. The highest serotonin content was found in plantain, while orange bell peppers had the highest melatonin content. Grape samples possessed higher trans- and cis-piceid, and trans- and cis-resveratrol contents than the other fruits. The results indicate that the combination of HPLC-MS detection and simple sample preparation allows the rapid and accurate quantification of serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol in fruits.     

Photo‐hardenable and patternable PDMS/SU‐8 hybrid functional material: A smart substrate for flexible systems

The fabrication of flexible electronics and systems, using rigid and brittle materials directly produced on stretchable substrate, leads to some issues and incompatibilities. These include rigidity for processing and modular flexibility for applications, macroscopic flexibility, and local rigidity to shield components from strain, compatibility with technological steps, and at the same time allowing patterning and machining. The development of smart substrate materials which meet such needs is therefore a promising route for flexible systems. Here, we demonstrate that by mixing polydimethylsiloxane (PDMS) and SU‐8 photoresist, we obtain both a photo‐hardenable and patternable stretchable hybrid material. A set of PDMS/SU‐8 and baking process combinations have been tested to determine an effective photo‐sensitive mixture. A standard photolithographic approach has been used on tensile test samples demonstrating a local hardening of millimeter‐sized ultraviolet exposed features and a local strain reduction reaching 35%. In addition, surface topography analysis and wet‐etching techniques have been used to demonstrate a light‐induced molding process and a selective etching of micrometer‐sized ultraviolet exposed patterns. The combined functional properties of the following material, its simplicity of implementation, and the well‐known assets of PDMS and SU‐8 make the PDMS/SU‐8 material very interesting and promising for various applications, especially stretchable systems. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1281–1291     

常温常压下吡咯及其衍生物的镍催化加氢反应考察

为进一步研究常温常压下吡咯及其衍生物的镍催化加氢反应,我们对试剂吡咯、吡咯烷和吡咯烷酮做了相应的催化加氢实验。并采用电镜（TEM-HREM）、X射线衍射（XRD）对Ni基催化剂的形貌、结构、加氢活性和超声波对其影响进行了检测,同时还用紫外吸收光谱、气相色谱等对加氢产物进行了分析考察。结果表明超声波能促进镍基催化剂活性,使镍微晶(111)晶面间距增大1.5%、并保持高分散态。常温常压下纳米镍基催化剂对吡咯、吡咯烷和吡咯烷酮的加氢反应显示一定的催化活性;吡咯加氢首先生成吡咯烷,进而使环打开生成低碳烃、氨等产物,总反应为零级,符合表面接触反应特征。     

Emerging Lipids from Arecaceae Palm Fruits in Brazil

Arecaceae palm tree fruits (APTFs) with pulp or kernel rich in oil are widely distributed in six Brazilian biomes. APTFs represent a great potential for the sustainable exploitation of products with high added value, but few literature studies have reported their properties and industrial applications. The lack of information leads to underutilization, low consumption, commercialization, and processing of these fruit species. This review presents and discusses the occurrence of 13 APTFs and the composition, physicochemical properties, bioactive compounds, and potential applications of their 25 oils and fats. The reported studies showed that the species present different lipid profiles. Multivariate analysis based on principal component analysis (PCA) and hierarchical cluster analysis (HCA) indicated a correlation between the composition of pulp and kernel oils. Myristic, caprylic, capric, and lauric acids are the main saturated fatty acids, while oleic acid is the main unsaturated. Carotenoids and phenolic compounds are the main bioactive compounds in APTFs, contributing to their high oxidative stability. The APTFs oils have a potential for use as foods and ingredients in the cosmetic, pharmaceutical, and biofuel industries. However, more studies are still necessary to better understand and exploit these species.