Optimizing extractants selection for efficient separation of phenols and nitrogen-containing heteroaromatics using hydrogen bond interaction strategies

Focusing on the use of imidazolium ionic liquids and quaternary ammonium salts-based deep eutectic solvents for the separation of phenols and nitrogen-containing heteroaromatics,the role of heteroaromatics as specific sites for hydrogen bond-based separation has been investigated.These environmentally friendly solvents are known for their ability to form hydrogen bonds with heteroatoms,a key aspect in separation processes.We quantified the hydrogen bond interaction energy to reach the threshold energy for efficient O-and N-heteroaromatics separation.This article provides an in-depth study of the structural nuances of different hydrogen bonding sites and their affinity properties while conducting a comparative evaluation of the separation efficiency of ionic liquids and deep eutectic solvents from a thermodynamic perspective.Results showed that phenols with dual hydrogen bonding recognition sites were easier to separate than nitrogen-containing heteroaromatics.Imidazolium ionic liquids were more suitable for the extraction of nonbasic nitrogen-containing heteroaromatics,and quaternary ammonium salts-based deep eutectic solvents are more effective for phenols and basic nitrogen-containing heteroaromatics,which was confirmed by Fourier transform infrared spectroscopy and empirical tests.Therefore,this study provides a theoretical basis for the strategy design and selection of extractants for the efficient separation of O-and N-containing aromatic compounds.

Ternary deep eutectic solvents catalyzed D-glucosamine self-condensation to deoxyfructosazine: NMR study

Ternary deep eutectic solvents(TDESs) comprising choline chloride(Ch Cl), glycerol and L-arginine were synthesized as catalysts and solvents for the conversion of D-glucosamine(GlcNH_(2)) into deoxyfructosazine(DOF). The interactions between these three components in the prepared TDESs were studied by ^(1)H-,^(35)Cl-NMR spectra and ^(1)H diffusion-ordered spectroscopy(DOSY) measurements. The chemical shift changes of active hydrogen in the ^(1)H-NMR spectra of TDES system and widening of signals in the^(35)Cl-NMR spectra confirmed the hydrogen bonding interaction between the components, which was further supported by the decrease of diffusion coefficients(D) of the TDES components according to ^(1)H DOSY measurements. The influences of reaction temperature and L-arginine content in the TDESs on the yield of DOF were also studied. The experimental results have shown that when the molar ratio of Ch Cl, glycerol, and L-arginine was 1:2:0.1, DOF was the major product with a yield of 22.6% at 90℃ for 120 min. The chemical shift titration indicated that the carboxyl group of L-arginine in the TDES is the catalytical active site, so the mechanism of the catalytic reaction between Glc NH_(2) and the TDES was proposed. Moreover, a reaction intermediate, dihydrofructosazine, was identified in the self-condensation reaction of Glc NH_(2) by an in situ ^(1)H NMR technique.

Ionic Liquids and Deep Eutectic Solvents and Their Use for Dissolving Animal Hair

In recent years, one of the priority areas of research in chemistry has become the processes carried out in an environment of liquid organic salts, the so-called ionic liquids (ILs), which are assessed as environmentally friendly or “green” alternatives to conventional organic solvents. ILs are non-volatile, highly polar solvents that dissolve many organic, inorganic, and organometallic compounds. Since they have no detectable vapor pressure, ILs are considered as potential substitutes for volatile organic compounds traditionally used as solvents. So-called deep eutectic solvents (DES) is a group of ILs that are liquid mixtures of a number of organic and (or) inorganic components taken in a certain ratio (eutectic or close to eutectic). DES deserve a special attention due to their negligible saturated vapor pressure, availability, low cost, as well as ability to dissolve at relatively high concentration of metal salts, metal oxides and various polymers. Particularly DES based on a mixture of choline chloride with urea (DES-1) or a mixture of choline chloride and adduct of urea with hydrogen peroxide (DES-2) give eutectics that are liquid at ambient temperature and have unusual solvent properties, including an ability to dissolve an animal hair in the presence of low concentration of sodium sulfide or ammonium thioglycolate. It was found that depending on the ratio between DES-1 and DES-2 in the mixture of two Deep Eutectic Solvents and the nature of sulfur-containing additive, the solubility of rabbit hair under used conditions, varies from 51% to 79%.

Cellulose Solubility in Deep Eutectic Solvents:Inspecting Quantitative Hydrogen-Bonding Analysis

According to the Kamlet-Abraham-Taft(KAT)polarity parameters(α,β,π*),polymers and solvents can be categorized as hydrogen-bond(H-bond)acidic(α>β)or H-bond basic(α<β).Recently,we proposed a quantitative hydrogen bonding(QHB)analysis to predict the solubility of polymers in ionic liquids(ILs)using the product ofΔαΔβ<0 as an indicator,whereΔαis the difference between the H-bond acidic parameters of the polymer and IL,andΔβis the difference in their basicity,while the prerequisite of the“complementary”principle(i.e.,that one component is H-bond acidic and the other is basic)is satisfied.Here,the applicability of QHB analysis was first confirmed by testing the solubilities of carefully chosen polymer/deep eutectic solvent(DES)pairs,as the DESs were eutectic mixtures dominated by hydrogen bonding interactions.Then,our attention focused on the solubility of cellulose in DESs.Our testing results as well as the typical published results were summarized,which indicate that the potential DESs for cellulose dissolution and regeneration must be of the H-bond basic type because the“complementary”principle should be satisfied as a prerequisite.However,the H-bond basic DESs investigated in this study do not show the superior solubility of cellulose that has been commonly observed for H-bond basic ILs,even if the criterion ofΔαΔβ<0 is satisfied for both DESs and ILs.Possible reasons for this discrepancy are given to understand the varying effectiveness in cellulose dissolution for H-bond basic DESs and ILs.

Machine-Learning-Assisted Design of Deep Eutectic Solvents Based on Uncovered Hydrogen Bond Patterns

Non-ionic deep eutectic solvents(DESs)are non-ionic designer solvents with various applications in catalysis,extraction,carbon capture,and pharmaceuticals.However,discovering new DES candidates is challenging due to a lack of efficient tools that accurately predict DES formation.The search for DES relies heavily on intuition or trial-and-error processes,leading to low success rates or missed opportunities.Recognizing that hydrogen bonds(HBs)play a central role in DES formation,we aim to identify HB features that distinguish DES from non-DES systems and use them to develop machine learning(ML)models to discover new DES systems.We first analyze the HB properties of 38 known DES and 111 known non-DES systems using their molecular dynamics(MD)simulation trajectories.The analysis reveals that DES systems have two unique features compared to non-DES systems:The DESs have①more imbalance between the numbers of the two intra-component HBs and②more and stronger inter-component HBs.Based on these results,we develop 30 ML models using ten algorithms and three types of HB-based descriptors.The model performance is first benchmarked using the average and minimal receiver operating characteristic(ROC)-area under the curve(AUC)values.We also analyze the importance of individual features in the models,and the results are consistent with the simulation-based statistical analysis.Finally,we validate the models using the experimental data of 34 systems.The extra trees forest model outperforms the other models in the validation,with an ROC-AUC of 0.88.Our work illustrates the importance of HBs in DES formation and shows the potential of ML in discovering new DESs.

低共熔溶剂抑制煤自燃的机理

化学阻化是防治煤自燃的重要手段之一,提出了一种基于低共熔溶剂(DES)的类离子液体阻化方法。首先,采用加热法制备并筛选了7种室温低共熔溶剂,分析了不同DES处理后煤样的官能团及热力学特性变化规律,在此基础上采用密度泛函理论分析了DES中氢键强度对煤理化性质的改性差异,推导了低共熔溶剂的阻化机制及其最佳氢键强度。研究结果表明:DES处理后煤中氢键网络被破坏重排,脂肪烃与芳香烃相对丰度增加了10%~37%,脂肪族支链结构参数降低了9.38%~20.65%,含氧官能团(C=O和C—O)相对丰度下降了22.88%~56.94%,游离的小分子化合物和矿物质被溶出。DES处理后煤的蒸发脱附阶段质量损失和吸氧增重阶段的吸氧量减小,低温氧化阶段和热分解阶段放热量降低,减小幅度分别为8.94%~77.51%和5.40%~26.20%。氢键受体(HBD)作用点位电负性越强,与氢键供体(HBA)形成的DES团簇氢键强度越大。DES中氢键强度与煤中氢键网络破坏程度呈正相关关系,与吸氧增重阶段的吸氧量和低温氧化放热量及矿物质脱除率呈局部相关性。DES通过溶解煤中活性成分削弱煤的低温氧化强度。并通过促进氢键重排,将低热稳定性氢键转换为热稳定性更高的环状氢键四聚体和OH—N氢键,以此提高煤的断键吸热量。但过高的氢键强度将会抑制活性侧链的脱除和溶解,因此抑制煤自燃的低共熔溶剂的最佳氢键强度应控制在69.45~160.00 kJ/mol。

银铜侧向复合材料界面结合机理分析

本文采用“包覆锭坯+扩散烧结+冷轧复合”联合工艺制备了银铜侧向复合带材,利用金相显微镜(OM)、扫描电镜(SEM)和能谱仪(EDS)观察分析银铜复合界面结构和元素分布,并分析其银铜复合界面的结合机理。结果表明,银铜复合界面形成过程为:1)银铜接触界面处凹凸不平的表面在轧制力的作用下相互咬合,形成机械结合界面;2)接触面在轧制力的作用下,银铜表面氧化膜破裂,新鲜表面质点间在轧制变形热的作用下产生原子结合;3)在扩散烧结过程中,银铜界面处的原子在高温作用下被激活,银铜原子相互扩散,在界面处发生银铜共晶反应形成液相金属层,随着烧结时间的延长,其共晶反应液相层厚度逐渐增加,随后冷凝结晶,使银铜实现侧向冶金结合。4)在后续中间退火过程中,共晶层与两侧的铜、银基体相互扩散,铜、银原子向更深的方向逐渐扩散,在靠近共晶层铜侧和银侧逐步形成固溶体层,使银与铜的结合强度进一步提高。银铜侧向复合界面结合机理包含机械咬合结合、接触共晶反应自钎焊结合和原子扩散结合3种,复合界面结合强度较好,剪切强度达220 MPa。

苦参碱-脂肪酸低共熔溶剂的制备及物性

构建了一系列基于苦参碱和脂肪酸的低共熔溶剂(Deep Eutectic Solvent,DES),探讨了脂肪酸烷基链长、氢键供体(HBD)与氢键受体(HBA)的物质的量之比对DES的理化性质的影响。结果表明:DES的密度、表面张力、电导率、极性随脂肪酸烷基链长度的增加而降低,黏度随脂肪酸链长的增大而增加;密度、表面张力和黏度随苦参碱与脂肪酸物质的量之比的减小而降低,电导率则随苦参碱与脂肪酸物质的量之比的减小而增加,上述不同的变化趋势源于苦参碱和脂肪酸分子之间相互作用的变化。

压阻加速度计的Au-Si共晶键合

通过将压阻加速度计上帽与结构片的键合 ( 36 5℃保温 10min) ,再进行下帽与结构片的键合 ( 380± 10℃保温2 0min) ,成功进行了三层键合 .测得的键合强度约为 2 30MPa.硅片 基体 /SiO2 /Cr/Au层和硅片之间键合时 ,SiO2 溶解而形成CrSi2 硅化物 .共晶反应因Cr层而被推迟 ,键合温度高出共晶温度 2 0℃左右 ,从而避免了由于Au元素向硅中扩入而造成的污染 ,进而避免可能造成的对集成微电子器件性能的影响 .试验还证明硅基体 SiO2 /Cr/Au/Poly Si/Au键合层结构设计模型也遵循这一键合过程中的原子扩散理论 .

胆碱基DES在EOR及CCUS中的应用与展望

深共晶溶剂(Deep Eutectic Solvent,DES)具有低饱和蒸气压、不易燃、不易爆、无毒、易降解、电化学和热稳定性好等优点。DES具有很好的表面活性,DES中的氢键网络与阴、阳离子表面活性剂具有很好的协同驱油作用。关于DES与常用表面活性剂的协同作用研究尚处于起步阶段,二者复配体系提高采收率(Enhanced Oil Recovery,EOR)机理尚不明确。在全面分析归纳总结胆碱基DES物理化学性质的基础上,探究了DES及其与阴或阳离子表面活性剂复配体系EOR机理,揭示了DES吸收二氧化碳机理,提出了DES在稠油油藏、低渗透油藏EOR以及碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)中的应用建议。研究结果对DES在EOR和CCUS的应用推广具有重要的指导意义。

一种Au-Si键合强度检测结构与试验

设计了一种Au Si键合强度检测结构。通过对一组不同尺寸压臂式测试结构的检测 ,可以由结构尺寸半定量地折算出键合面的键合强度 ;采用同一结构尺寸 ,可以比较不同条件下键合强度的相对大小 ;此结构还可用于其它类型键合强度的比较和测试。通过压臂法检测了Au Si键合强度 。

脂肪酸低共熔溶剂对姜黄素的溶解作用

制备了辛酸(C8)分别与癸酸(C10)、月桂酸(C12)及肉豆蔻酸(C14)形成的C8-C10、C8-C12、C8-C143种脂肪酸低共熔溶剂(DES)。C8-C10、C8-C12、C8-C14对姜黄素的溶解度分别为1.11、1.24、1.44 mmol/L,比姜黄素在水中的溶解度分别提高了约29、32、38倍。通过Gaussian模拟计算,得到姜黄素与C8、C10、C12、C14形成的分子缔合物的吉布斯自由能分别为−48.49、−64.27、−91.26、−120.59 kJ/mol。姜黄素与烷基链最长的C14形成“三明治”型分子缔合物,具有最强的氢键和疏水缔合作用,使姜黄素在C8-C14脂肪酸DES中表现出最高的溶解度和最强的紫外吸收及荧光发射强度。姜黄素在C8-C10、C8-C12、C8-C143种脂肪酸DES中均具有显著提高的稳定性和1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力。

应用于三维集成的金铟键合技术研究

由于埋置芯片耐受温度的限制,圆片级低温键合技术是MEMS三维集成的关键工艺之一。金属In凭借自身熔点低而金属间化合物(Intermetallic compound, IMC)熔点高且性质稳定的特点,使得Au-In固液扩散键合法成为颇具前景的低温键合技术之一。本文采用Au-In二元共晶化合物进行圆片级低温键合,在键合衬底上先后制备了0.4μm的SiO/SiN介质层、3.5μm的Au层和1.7μm的In层,然后分别研究了先预加热键合极板再贴合圆片和先贴合再加热两种键合方式。电性能测试、An/In组分分析和剪切试验结果表明:先贴合再加热的键合样品芯片形成了性质稳定的IMC组分,具有良好的电学互连特性稳定性,且剪切强度达到100 MPa。一定样本容量的实验结果证明隔绝键合前Au-In的相互扩散能够有效增强键合的可靠性。

Controlling reversible complexation-mediated polymerization(RCMP)via deep eutectic solvents:fast kinetics,narrow molecular weight distribution and mechanistic insights

The exploitation of new green polymerization avenues for the effective synthesis of polymers by reversible-deactivation radical polymerization plays a critical role in pursuing the development of polymeric materials.In this work,serials of deep eutectic solvents(DES)with intermolecular-hydrogen-bonding interaction were constructed as catalysts and medium for actuating reversible complexation-mediated polymerization(RCMP)for the first time,yielding methacrylate polymers with high monomer conversion and narrow dispersion molecular weight in both water and oil systems.The mechanism and elementary reaction of RCMP were explored deeply,revealing that the complexation of initiator with DES to generate radicals was a ratecontrolling step and intermolecular-hydrogen-bond was primary factor to influence polymerization rate.Moreover,the insights of density functional theory calculations revealed that negative electrostatic potential ensured nucleophilic capacity.This investigation demonstrated the considerable potential of DES for RCMP,which is anticipated for other polymerization applications as a novel medium mode.

可充电锌离子电池共晶电解液的研究进展

可充电锌离子电池(RZIBs)因高安全性、低成本以及环境友好等优势广受关注。但传统水系电解液中水的高活性导致锌负极在循环过程中面临着枝晶和副反应问题,限制了RZIBs的发展。共晶电解液通过氢键和配位效应调节Zn^(2+)离子溶剂化结构中水分子数量,有效解决了上述问题。此外,其具有合成简单、无腐蚀性和环境友好等优势,在RZIBs领域备受关注。介绍了共晶电解液的基本原理和定义,然后重点阐述了共晶电解液在RZIBs中的应用现状,最后对共晶电解液的发展前景进行了展望,为制备出优异的共晶电解液提供了重要思路。

FeCl_(3)基三元低共熔溶剂分离毛竹木质素效率研究

提高低共熔溶剂(DES)分离木质素效率是实现木质纤维资源高值化利用的前提。本研究基于酸性、中性及碱性二元DES分离毛竹木质素的方法,设计三元DES以提高木质素分离效率,优化三元DES分离木质素的工艺条件,采用Kamlet-Taft溶剂化显色参数,定量分析DES的氢键性能,并对DES分离所得木质素进行结构表征。结果表明,二元DES分离木质素时,木质素溶出率由高到低依次为:酸性DES>中性DES>碱性DES,由FeCl_(3)-聚乙二醇400-氯化胆碱构成的三元DES,其木质素溶出率较高,分离毛竹木质素的最佳工艺条件为:温度130℃、时间3 h、质量比1∶15、加水质量比10%(相对于聚乙二醇400质量);在此工艺条件下,木质素溶出率可达96.36%。FeCl_(3)的引入增加了三元DES的氢键碱性,使其具有更强的氢键接受能力。拉曼光谱和傅里叶变换红外光谱分析表明,DES分离所得毛竹木质素的主要基本结构单元为愈创木基型和紫丁香基型,且结构完整性优于碱木质素。本研究结果可为DES高效清洁分离毛竹木质素提供参考。

弱碱性低共熔溶剂溶解角蛋白过程及氢键机制

利用低共熔溶剂(DES)较强的氢键拆解能力定向解构角蛋白分子间的次级键,结合还原剂和DES高效断裂二硫键的能力,建立了一种弱损溶解并提取鸡毛中角蛋白的方法。以氯化胆碱为氢键受体(HBA)、乙醇胺、乙二醇、乳酸等为氢键供体(HBD),设计合成了3类(碱性、中性和酸性)13种功能性的DES,考察了还原剂用量(以鸡毛质量为基准,下同)、温度、DES中水质量分数对角蛋白相对分子质量和提取率的影响,通过密度泛函(DFT)理论计算和溶剂显色参数分析了DES内部的氢键网络结构,研究了DES对鸡毛角蛋白的弱损溶解机制。结果表明,以乙醇胺为HBD,不添加还原剂,在n(乙醇胺)∶n(氯化胆碱)=2∶1、DES中不含水、温度65℃、0.5h的最优条件下,再生角蛋白提取率为31.8%,相对分子质量最高,为66000。以乙醇胺为HBD制备的DES具有还原性,作为碱性DES,其内部的氢键数量多,氢键作用小,氢键能低,可以打乱鸡毛内部的氢键网络,而不会对鸡毛二级结构造成太大破坏。

共蒸发法制备金锡共晶焊料环及其性能研究

采用电子束共蒸发法制备了金锡共晶(Au80Sn20)焊料环,与非制冷红外探测器芯片进行气密性封装。通过SEM、AFM、X-ray、振荡测试以及测漏氦等方式验证了封装后芯片的气密性和可靠性。结果表明:键合后焊料环无明显缺陷,仅存在轻微溢料现象;经过振荡测试,溢料无脱落、无位移,且芯片密封性能可达到1×10^(-3) Pa/(cm^(3)·s),符合探测器的气密性要求。

Au-Si共晶扩散连接单晶硅接头的微观组织和性能研究

采用直接共晶和预共晶连接两种方法,对块体单晶硅扩散连接进行试验研究。结果表明:单晶硅接头界面主要由残留Au层、桥状硅和微孔组成。试验中微孔是个难以避免的缺陷,但随着连接温度升高,微孔数量会减少,即焊合率会增大。预共晶连接能有效地阻止微孔的产生,700℃时预共晶连接焊合率达87%,而直接共晶连接仅57%。预共晶连接接头抗拉强度较直接共晶连接低。因为预共晶连接主要在Au层发生断裂,故预共晶连接的残留Au层是个弱结合。直接共晶连接残余Au层很薄,平均厚度不足0.34μm,断裂主要发生在Au-Si界面上。