SO42-/TiO2-Al2O3固体超强酸催化合成甲酸乙酯

用SO4^2-／TiO2-Al2O3固体超强酸作催化剂催化合成甲酸乙酯,考察了催化剂的活化温度、催化剂用量、反应物配比对酯化反应的影响。结果表明,SO4^2-／TiO2-Al2O3固体超强酸是合成甲酸乙酯的良好催化剂,并且可以重复使用。在醇酸摩尔比2：1、催化剂用量（以每摩尔甲酸计）2g、反应时间4h的最佳条件下,甲酸乙酯的产率可达99．5％。     

正己烷和乙酸乙酯间歇共沸精馏分离共沸剂的研究

正己烷和乙酸乙酯形成最低共沸物,采用间歇共沸精馏方法分离回收时,共沸剂的选择和用量直接影响实验效果。研究了正己烷-乙酸乙酯共沸物系间歇共沸精馏法分离适宜的共沸剂,并从理论上和实验中考察了共沸剂与原料适宜的配比。实验结果表明,丙酮为合适的共沸剂,当丙酮和正己烷的质量比为1.15时,正己烷和乙酸乙酯的收率最高,分别达75.15%和73.89%。通过实验绘制了正己烷-乙酸乙酯-丙酮三元物系的剩余曲线,确定了正己烷-乙酸乙酯共沸物系分离步骤:共沸精馏塔中馏出丙酮和正己烷的共沸物和高纯度的乙酸乙酯;萃取塔中用水萃取丙酮和正己烷的混合物得到较纯的正己烷;萃取后的丙酮水溶液由共沸剂精馏回收塔回收丙酮。     

乙酸乙酯-异丙醚和乙酸乙酯-四氢呋喃物系常压汽液平衡数据的测定

在常压(101.3kPa)下,用汽液平衡釜测定了乙酸乙酯-异丙醚和乙酸乙酯-四氢呋喃二组分物系的汽液平衡数据。所测得的汽液平衡数据符合热力学一致性检验。利用修正的UN IFAC方程和W ilson方程对实验数据进行了关联,得到了W ilson方程的参数Λ12和Λ21。对于乙酸乙酯(1)-异丙醚(2)二组分物系,Λ12为0.387 7,Λ21为1.481 2,实验值与W ilson方程计算值的平均偏差为0.003 5;对于乙酸乙酯(1)-四氢呋喃(2)二组分物系,Λ12为0.929 4,Λ21为0.731 0,实验值与W ilson方程计算值的平均偏差为0.004 6。实验结果表明,乙酸乙酯-异丙醚和乙酸乙酯-四氢呋喃二组分物系均不形成共沸物。     

纳米钛硅分子筛TS-1催化甲乙酮氨氧化合成甲乙酮肟

以纳米钛硅分子筛TS-1为催化剂，采用三口玻璃反应器研究了甲乙酮（MEK）氨氧化的反应性能。采用SEM、TEM和XRD等分析手段表征了TS-1的晶粒尺寸。考察了TS-1的晶粒尺寸、反应物的加料方式、溶剂、催化剂用量、反应温度和反应物料配比对甲乙酮氨氧化反应性能的影响。结果表明，甲乙酮氨氧化反应的最佳反应条件为：75℃，n（NH3）：n（H2O2）：n（MEK）=4．0：1．5：1．0，TS-1用量21．6g（以1mol MEK计）；H2O2和氨水连续进料，最佳溶剂为叔丁醇或叔丁醇和水的混和液。在最佳反应条件下，甲乙酮的转化率和甲乙酮肟的选择性可分别达到99．4％和99．8％。     

Transparent,Stimuli‐Responsive Films from Cellulose‐Based Organogel Nanoparticles

The use of bio‐based nanoscaled cellulose for the construction of novel functional materials has progressed rapidly over the past years. In comparison to most of studies starting with the hydrophilic nanoscaled cellulose, surface‐stearoylated cellulose nanoparticles (SS‐CNPs) are used in this report for the construction of multifunctional, responsive films. SS‐CNPs with an average size of 115 ± 0.5 nm are obtained after the surface‐modification of cellulose under heterogeneous conditions. Crystalline cellulose core is present within SS‐CNPs according to solid‐state ¹³C nuclear magnetic resonance (NMR) spectroscopy. SS‐CNPs show excellent dispersibility in nonpolar solvents and form temperature‐responsive organogels in tetrahydrofuran (THF) at low temperature or after long time storage at room temperature. Moreover, transparent and self‐standing films of SS‐CNPs from their THF‐suspension show solvent‐responsive surface wettability and responsive shape‐memory property. SS‐CNPs can also be used for the fabrication of nanocomposite films together with nonpolar compounds, such as (2‐stearoylaminoethyl) rhodamine B. Thus, these novel SS‐CNPs derived from sustainable cellulose fibers are promising candidates for the construction of novel functional materials.     

Nanocellulose-Carboxymethylcellulose Electrolyte for Stable,High-Rate Zinc-Ion Batteries

Aqueous Zn ion batteries (ZIBs) are one of the most promising battery chemistries for grid-scale renewable energy storage. However, their application is limited by issues such as Zn dendrite formation and undesirable side reactions that can occur in the presence of excess free water molecules and ions. In this study, a nanocellulose-carboxymethylcellulose (CMC) hydrogel electrolyte is demonstrated that features stable cycling performance and high Zn²⁺ conductivity (26 mS cm⁻¹), which is attributed to the material's strong mechanical strength (≈70 MPa) and water-bonding ability. With this electrolyte, the Zn-metal anode shows exceptional cycling stability at an ultra-high rate, with the ability to sustain a current density as high as 80 mA cm⁻² for more than 3500 cycles and a cumulative capacity of 17.6 Ah cm⁻² (40 mA cm⁻²). Additionally, side reactions, such as hydrogen evolution and surface passivation, are substantially reduced due to the strong water-bonding capacity of the CMC. Full Zn||MnO₂ batteries fabricated with this electrolyte demonstrate excellent high-rate performance and long-term cycling stability (>500 cycles at 8C). These results suggest the cellulose-CMC electrolyte as a promising low-cost, easy-to-fabricate, and sustainable aqueous-based electrolyte for ZIBs with excellent electrochemical performance that can help pave the way toward grid-scale energy storage for renewable energy sources.     

All‐Cellulose‐Based Quasi‐Solid‐State Sodium‐Ion Hybrid Capacitors Enabled by Structural Hierarchy

Na‐ion hybrid capacitors consisting of battery‐type anodes and capacitor‐style cathodes are attracting increasing attention on account of the abundance of sodium‐based resources as well as the potential to bridge the gap between batteries (high energy) and supercapacitors (high power). Herein, hierarchically structured carbon materials inspired by multiscale building units of cellulose from nature are assembled with cellulose‐based gel electrolytes into Na‐ion capacitors. Nonporous hard carbon anodes are obtained through the direct thermal pyrolysis of cellulose nanocrystals. Nitrogen‐doped carbon cathodes with a coral‐like hierarchically porous architecture are prepared via hydrothermal carbonization and activation of cellulose microfibrils. The reversible charge capacity of the anode is 256.9 mAh g^?1 when operating at 0.1 A g^?1 from 0 to 1.5 V versus Na⁺/Na, and the discharge capacitance of cathodes tested within 1.5 to 4.2 V versus Na⁺/Na is 212.4 F g^?1 at 0.1 A g^?1. Utilizing Na⁺ and ClO₄^? as charge carriers, the energy density of the full Na‐ion capacitor with two asymmetric carbon electrodes can reach 181 Wh kg^?1 at 250 W kg^?1, which is one of the highest energy devices reported until now. Combined with macrocellulose‐based gel electrolytes, all‐cellulose‐based quasi‐solid‐state devices are demonstrated possessing additional advantages in terms of overall sustainability.     

An Optically Responsive Soft Etalon Based on Ultrathin Cellulose Hydrogels

Stimuli‐responsive optical etalons are an exciting class of next‐generation sensors because they are scalable, cost‐effective and offer tunability of their optical response across the entire UV–vis–NIR wavelength range. In this study, double‐network cellulose hydrogels are used as a soft, responsive medium and are incorporated into Fabry–Pérot optical etalons. The thin cellulose hydrogel layer can be solution processed. The hygroscopic hydrogel undergoes both refractive index and thickness changes in response to changes in humidity. This leads to strong changes in reflection due to optical interference within the metal–insulator–metal (MIM) cavity. The response can be optimized by adjusting the chemical crosslinker ratio. These flexible MIM structures provide a robust platform for optically based chemical sensors.     

Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril

Cellulose nanofibril (CNF) was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin (PAE) or cationic starch (CS) was used as the cationic component. Their strengthening effects were investigated for low-basis-weight (30 g/m²) paper composed of a mixture of fully bleached softwood and hardwood pulp in a 4:1 mass ratio. Using the PAE/CNF or CS/CNF dual system, it was generally easier to achieve higher wet and dry tensile strengths of paper compared to the paper using the single PAE or CS system. For example, the paper using the PAE (0.4%)/CNF (0.3%) dual system exhibited 89% higher wet tensile strength than the paper using the single PAE (0.4%) system, and the paper using CS (1.3%)/CNF (0.3%) dual treatment showed 21% higher dry strength than that using the single CS (1.3%) system. However, the PAE/CNF system only showed small improvement in the dry strength of paper (11% higher than that of paper using the single PAE system), so did the CS/NFC system on wet strength improvement (only 17% higher than that of paper using the single CS system).     

Highly Conductive Microfiber of Graphene Oxide Templated Carbonization of Nanofibrillated Cellulose

Microfibers with conductivity of 649 ± 60 S/cm are introduced through a carbonization of well‐aligned graphene oxide (GO) – nanofibrillated cellulose (NFC) hybrid fibers. GO acts as a template for NFC carbonization, which changes the morphology of carbonized NFC from microspheres to sheets while improving the carbonization of NFC. Meanwhile, the carbonized NFC repairs the defects of reduced GO (rGO) and links rGO sheets together. The GO templated carbonization of NFC as well as the alignment of the building blocks along the fiber direction leads to excellent conductivity. Conductive microfibers are evaluated as lithium ion battery anodes, which can be applied in wearable electronics. This approach to make conductive microfibers and the low cost raw materials used in this work may be applied to other carbon based conductive structures.