Aluminium electrodeposition under novel conditions from AlCl3-urea deep eutectic solvent at room temperature

The electrodeposition of aluminium on glassy carbon and aluminium substrates from AlCl3-urea deep eutectic solvent(DES) system at near room temperatures was investigated,without additional purification of the chemicals used to prepare the electrolyte and without rigorous control of moisture and oxygen present in the working space.The effects of changing temperature,working potential,controlled deposition current density and deposition time on the morphology of deposited aluminium without stirring of the electrolyte were recorded.Using potentiostatic and galvanostatic techniques,aluminium was electrodeposited from the deep eutectic solvent(n(AlCl3):n(urea)=1.6:1) onto glassy carbon and aluminium substrates at temperatures ranging from 25 to 50℃.Using SEM,EDS and XRD techniques,substrates were studied and confirmed the presence of aluminium deposits following both potentiostatic and galvanostatic regimes.The shape and size of Al grains deposited depended on the time of deposition and varied in size from nanometers to micrometers and in shape from regular crystal forms to needle-like and flake-like structures.

Okara Cellulose Nanofibrils Produced by Pretreatment with Sustainable Deep Eutectic Solvent Coupled with Various Mechanical Treatments

In this study,a green,environmentally friendly method for rapid cellulose nanofribril(CNF)preparation with a significant cost advantage was developed.Pretreatment with a deep eutectic solvent(DES)synthesized from oxalic acid dihydrate and choline chloride(ChCl-O)was combined with various mechanical treatment methods to produce okara CNFs from agricultural waste,with different diameter distributions.The results showed that high-speed stirring produced CNFs with an average diameter of 27 nm.This method was advantageous because it consumed about 94%less energy than traditional high-pressure homogenization method.The DES recovery rate was more than 90%,and DES served as a highly effective treatment,indicating that DES pretreatment is an economical,convenient,and effective strategy for okara CNF preparation.

Efficient and selective extraction of sinomenine by deep eutectic solvents

Sinomenine is the main bio-active ingredient of Sinomenii Caulis and usually produced by solventextraction techniques. However, the extraction of sinomenine suffers from the lack of highly efficient and environmentally-benign solvents. In this work, deep eutectic solvents(DESs) based on fragrances were synthesized, hydrogen-bond donors(HBDs) and hydrogen-bond acceptors(HBAs) components of DESs were identified and their extraction ability for sinomenine was evaluated and the extraction conditions were optimized by single-factor and orthogonal design experiments. It was found that the hydrogen-bonding interaction between sinomenine and DESs was the main extraction driving force and there was no explicit relationship between the extraction ability and the hydrophobicity of the DESs. The DESs could be recycled and sinomenine could be recovered quantitatively via backextraction. High-purity sinomenine((95.0 ± 2.3)%) could be produced. These findings suggest that DESs are highly-effective solvents for the isolation of sinomenine and exhibit great potential for the extraction of other bio-active compounds.

Dissolution of highly molecular weight cellulose isolated from wheat straw in deep eutectic solvent of Choline/L-Lysine hydrochloride

Green solvents for cellulose dissolution is a key topic for green chemistry,especially natural cellulose with high molecular weight,and there are scarce solvents reported.Deep eutectic solvent(DES)is a typical kind of green solvent that has been attracted much attention recently.Here,high molecular weight natural cellulose(DP>3000)was first isolated from wheat straw and then be directly dissolved in the choline/L-lysine(Ch/Lys)DES.The solution owns excellent stability,and the solubility reaches^5%.Rheological studies revealed that the natural cellulose can be well dispersed in the DES solution and showed gelation at high concentrations.The dissolved cellulose can be regenerated when the dilute acid aqueous solution was added into the solution.It provides an energy conversation and an environmentally friendly route to prepare a cellulose solution,which makes it possible to convert cellulose to valuable chemicals and materials in its homogeneous solution.

Tribological study of two ammonium chloride-decanoic acid deep eutectic solvents(DESs)as high-performance lubricants

Deep eutectic solvents(DESs)are acknowledged as a novel class of functional liquid.DESs share similar physical properties with ionic liquids(ILs)and have the potential to be a novel class of lubricants.In this study,two DESs,namely tetrabutylammonium chloride-decanoic acid DES(C4-DES)and methyl tricaprylmethylammonium chloride-decanoic acid DES(C8-DES),were synthesized,and their physico-chemical properties and tribological performances were evaluated.Post-analysis of the rubbing surfaces used multiple techniques to gain insights into the lubrication mechanisms.Results show that the coefficient of friction(COF)and wear were reduced by approximately 29%and 91%for the C4-DES,and 36%and 94%for the C8-DES,compared to an ester base oil.The friction reduction behavior of the DESs is attributed to the monolayer adsorption of the polar group in the decanoic acid(DEAC),whose effectiveness is affected by the component of the ammonium salts in the DESs and the operating temperatures.In addition to the adsorbed film,worn surface analysis revealed that an ultra-thin tribochemical film with a thickness of 3–7 nm was formed on the surfaces lubricated with the C8-DES.The composition of the film was studied,and the lubrication mechanisms of the two DESs were discussed.

Oxidation of furfural to maleic acid and fumaric acid in deep eutectic solvent(DES)under vanadium pentoxide catalysis

Furfural is an alternative feedstock and has been used for the production of maleic acid(MA)and fumaric acid(FA)by an oxidation process.Deep eutectic solvents(DESs)were used as the green solvents while sodium chlorate was used as an oxidant and vanadium pentoxide was used as the catalyst at 70-90°C under atmospheric pressure.It was found that several acidic DESs are valid,such as acetic acid/choline chloride(AA/ChCl)and propionic acid/choline chloride(PA/ChCl),and AA/ChCl DES was selected as the solvent for the conversion.The optimal DES is AA/ChCl,and the effect of the amount of oxidant,time,and temperature on the yield of the MA and FA has been systematically studied,and the conversion of furfural can reach 100%while the yield of the MA and FA reached 66.5%under reaction temperature of 80℃ for 12 h,which provides a new green route to synthesis valuable monomers from furfural.

固体有机物合成的低温共熔溶剂的研究及其对纤维素的溶解

对固体有机物尿素、己内酰胺、乙酰胺以不同配比制备的尿素/己内酰胺、尿素/乙酰胺和乙酰胺/己内酰胺3种低温共熔溶剂进行了研究,并考察了其物理化学性质（熔点、电导率等）.结果表明,随着物质的量比的不同,低共熔溶剂的熔点不同,最佳物质的量比分别为1∶3、1∶2和1∶1,在最佳物质的量比下的熔点分别为30℃、48℃和18℃.低温共熔溶剂的电导率在10-4～10-5 S/m数量级,随温度的升高,电导率增加,电导率与温度符合Arrhenius方程.IR测试结果显示,固体有机物各自分子内的氢键消失,形成了新的氢键.初步探讨了纤维素在3种体系中的溶解性能,结果显示,3种溶剂对纤维素有一定的溶解能力.通过分析得出,该类共熔体溶剂为酰胺类溶剂,主要通过其羰基上的氧原子和氨基上的氮原子与纤维素上的羟基形成氢键.IR和XRD测试结果表明,纤维素和再生纤维素有相似的结构,但纤维素的晶型从Ⅰ型转变为Ⅱ型.

氯化胆碱/草酸低共熔溶剂高效脱除模拟油中硫

在100℃下,将草酸与氯化胆碱按照等物质的量混合搅拌制备氯化胆碱/草酸低共熔溶剂(Ch Cl/H_2C_2O_4)。采用红外光谱(IR),热重(TGA)和氢谱(1HNMR)对其结构分别进行了相关表征分析。以Ch Cl/H_2C_2O_4低共熔溶剂作为萃取剂和催化剂,过氧化氢为氧化剂氧化脱除模拟油中的二苯并噻吩。分别考察了反应温度、过氧化氢用量以及不同含硫化合物对脱硫率的影响。实验表明最优反应条件为5 m L模拟油,1 m L的Ch Cl/H_2C_2O_4低共熔溶剂,0.3 m L的过氧化氢,反应温度为40℃,在160 min的最佳反应条件下DBT的脱除率高达93.4%。结果表明其表观活化能较低。在5次循环反应以后,其脱硫效果略有降低,表明该低共熔溶剂的催化脱硫活性和稳定性较高。

Degradation of Alkaline Lignin in the Lactic Acid-Choline Chloride System under Mild Conditions

Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be used as an excellent green degradation method.This paper introduces the degradation mechanism and effect of the lactic acid-choline chloride DES system in dissolving and degrading alkaline lignin,and the final solvent recovery.It can also be found from the scanning electron microscope(SEM)images that the surface of the degraded solid product is transformed from smooth to disordered.Fourier transform infrared(FTIR)spectroscopy and 1H-NMR spectroscopy were used to characterize the changes in lignin functional groups during DES treatment.The results showed that the content of phenolic hydroxyl groups increased after degradation,indicating that theβ-O-4 ether bond was broken.The molecular weight of the degraded lignin was observed by gel permeation chromatography(GPC),and the lignin residue with low molecular weight and narrow polydispersity index was obtained.The lowest average molecular weight(Mw)reached 2512 g/mol.The ratio of oxygen to carbon atoms in lignin increased substantially during degradation as measured by X-ray photoelectron spectroscopy(XPS),probably because DES treatment was accompanied by many oxidation reactions,which led to significant structural changes in lignin and a large number of ether bond breakage reactions during the reaction.The main final degradation products are aromatic monomers,vanillin,butyrovanillone,etc.

低温共熔溶剂[ChCl][CrCl_3·6H_2O]_2室温催化酯化反应

以氯化胆碱(ChCl)与金属氯化物合成的一系列低温共熔溶剂(DES)为催化剂,以正丁醇和乙酸的酯化反应为模板反应,通过气相色谱研究了其催化产率。经过条件优化,低温共熔溶剂[ChCl][CrCl_3·6H_2O]_2催化乙酸和丁醇反应的产率可达到93%。对酯化体系进行简单处理,回收的低温共熔溶剂(DES)仍有较高的催化活性,可重复利用。与传统的无机酸催化剂相比,DES催化酯化反应具有以下优点:催化活性高,能够高效高选择性的合成有机酯;DES的合成简单,成本低廉;酯化反应可以在室温下进行;DES可以重复使用。

Construction of ternary PEG200-based DESs lubrication systems via tailoring tribo-chemistry

Designing novel lubricants with easily customized structures,devisable compositions,and simple and economic synthesis over traditional lubricants is critical to fulfilling complex applications,prolonging machine lifetime,and saving energy.Deep eutectic solvents(DESs),which show tunable composition,adjustable structure,easy fabrication,and environmental friendliness,are promising candidates for variable and complicated lubricants applications.To promote the use of DESs as lubricants,a series of PEG200-based DESs with active heteroatoms were fabricated to tailor the tribological performance via tribo-chemistry.Thereinto,PEG200/boric acid(BA)DES shows optimal lubrication performance by forming tribo-chemical reaction film composited of B2O3,iron oxides,and FeOOH,and PEG200/thiourea(TU)DES displays abrasive wear-reducing property by producing FeS tribo-chemical film.Given the excellent abrasive wear-resistance of PEG200/TU DES and friction reduction of PEG200/BA DES,ternary PEG200/BA/TU DESs,composited of PEG200/TU DES and PEG200/BA DES,are first exploited.The ternary DESs possess superior wettability and thermal stability,which render them potential lubricants.Tribological tests of the ternary DESs demonstrate that synergistic lubrication is achieved by forming a transfer film consisting of FexBy,BN,B2O3,and FeS.Wherein FexBy,BN,and B2O3 increase load bearing of the film,and FeS mitigates severe abrasive wear.The proposed design philosophy of novel DESs as lubricants opens up a unique realm that is unattainable by traditional DESs lubrication mechanisms and provides a platform to design next-generation DESs lubrication systems.

Bioactive compounds of deep eutectic solvents extracts of Hypericum perforatum L.:Polyphenolic-organic acid profile by LC-MS/MS and pharmaceutical activity

Deep eutectic solvents(DESs)are known as environmentally-friendly solvents that have emerged as an alternative to conventional organic solvents in recent years.In this study,the effects of ten different DESs on the extraction of bioactive components from the Hypericum perforatum were investigated.Total phenolic content,total flavonoid content,phenolic profile(32 phenolics),organic acid profile(52 organic acids),as well as antioxidant and antimicrobial activities of H.perforatum extracts prepared using DESs and ultrasonic-assisted extraction method were determined.Total phenolic,total flavonoid content,and antioxidant activities of extracts were determined between 3.10±0.86-16.64±2.09 mg GA/g,0.02±0.00-12.29±0.30 mg QE/g,and 8.40±0.50-44.78±2.66 mg TE/g,respectively.DES2(choline chloride:ethylene glycol)and DES7(choline chloride:lactic acid)demonstrated higher extraction success than other DESs for extracting phenolics and organic acids,respectively.DESs prepared using organic acid as hydrogen bond donor were found to have an antibacterial effect against all bacterial samples.However,the inhibitory effect against yeast-like fungi was observed in a narrower spectrum.Moreover,the results from principal component analysis also confirmed that the type of solvent used for extraction has a significant influence on the phenolics,organic acid,and other parameters.As a result,it was seen that DES components directly affect the extraction efficiency of target compounds from H.perforatum.This is a first and original report about use of DESs in extracting different bioactive components from H.perforatum.

Highly Efficient Low Melting Mixture Catalyzed Synthesis of 1,8-Dioxo-dodecahydroxanthene Derivatives

A low melting citric acid-urea mixture was found to be a new and effective promoting medium for the environmentally friendly synthesis of 1,8-dioxo-dodecahydroxanthene derivatives by condensation of aromatic alde-hydes and cyclic 1,3-dicarbobonyl compounds. This deep eutectic solvent acts as both the reaction medium and catalyst, furnishing xanthenediones in high to excellent yields.