Extraction of palladium(Ⅱ) with OTMSO from acidic media

The extraction of palladium(Ⅱ) from acidic media with cyclic sulfoxidedervva-tive-α-octyl-tetrahydrothiophene-1-oxide (OTMSO) was investigated. The extraction efficiencyof palla-dium(Ⅱ) with OTMSO is 97.1% at 0.3 mol·L^(-1) OTMSO. The plots of the extractionefficiency for palla-dium(Ⅲ) appear to lie on a convex curve having a minimum of extractionefficiency at 1-2 mol·L^(-1) HCl. The extraction reaction of palladium(Ⅱ) with OTMSO isendothermic, and ΔH_(OTMSO)~θ = 12.2 kJ·mol^(-1). The coordination number was studied with slopemethod. The result indicates that coordination number is 2. FT-IR spectra were used to analyze thestructure of complex and coordinated atom in complex. Pd is coordinated with both oxygen and sulfuratom in S=O group in OTMSO. The situation and intensity of peaks contributed by complex preparedfrom various acidity were different. The recovery of palladium(Ⅱ) with OTMSO from scrap containingpalladium was discussed. After silver and bismuth were removed, the feed solution was extractedthree times by 40% (volume fraction) OTMSO-kerosene. The loaded organic phase was scrubbed threetimes, and stripped three times by 2 mol·L^(-1) NH_3·H_2O solution. The total recovery ofpalladium was 99.8%, and the purity of palladium was 99.8 %.

Extraction chromatography–electrodeposition(EC–ED) process to recover palladium from high-level liquid waste

The extraction chromatography–electrodeposition(EC–ED) process was proposed for the quantitative recovery of palladium from high-level liquid waste(HLLW) in this study. The process coupled the extraction chromatography method to obtain the decontamination of Pd(II) from HLLW with the electrochemical method to recover metallic palladium from the concentrated solution.Separation of Pd(II) from a nitric acid medium by extraction chromatography using iso Bu-BTP/SiO_2-P adsorbent and the electrochemical behavior of Pd(II) in nitric acid solution in the presence of thiourea(TU) were investigated.iso Bu-BTP/SiO_2-P exhibited a high selectivity for Pd(II)over other fission products(FPs), and Pd(II) could be desorbed by TU from loaded BTP/SiO_2-P. The adsorbent performed good stability against HNO_3 because the adsorption performance kept Pd(II) after extended contact with HNO_3 solution. The column experiment achieved the separation of Pd(II) from simulated HLLW successfully.The electrochemical behavior of Pd(II) in palladium desorption solution containing TU and nitric acid was investigated at a platinum electrode by cyclic voltammetry. A weak reduction wave at-0.4 V was due to the reduction in Pd(II) to Pd(0), and the deposition process wasirreversible. In electrowinning experiments, a maximum of92% palladium could be obtained.

Extraction of palladium(Ⅱ) from hydrochloride solutions with 2-n-octyl-4-isothiazolin-3-one as novel extractant

Solvent extraction of palladium （Ⅱ） from hydrochloric acid solution with 2-n-octyl-4-isothiazolin-3-one （OIT）/cyclohexane was studied. Effects of different parameters on extraction efficiency were evaluated. 99.96 % and 98.26 % palladium （Ⅱ） could be effectively extracted with 0.018 mol·L^-1 OIT/cyclohexane of 0.1 and 4.0 mol·L^-1 HCl medium, respectively. Nonpolar solvent and low acidity could improve the extracting efficiency, and successfully strip palladium （Ⅱ） from the loaded organic phase was achieved with 0.5 mol·L^-1 （NH2）2CS solution. It was proposed that the extraction of Pd com-plexes from HCl medium proceeded through the ion-association mechanism by slope method, NMR and FF-IR spectra.

Extraction of gold, palladium, and platinum from acidic media with cyclic sulfoxide derivative

The extraction of gold （Ⅲ）, palladium （Ⅱ）, and platinum （Ⅳ） from the acidic media with the cyclic sulfoxide derivative of α-dodecyl-tetrahydrothiophene 1-oxide （dtmso） was investigated. Gold （Ⅲ）, palladium （Ⅱ）, and platinum （Ⅳ） could be separated from the acidic media with suitable sulfoxide concentration and acidity. The extraction reaction of gold （Ⅲ）, palladium （Ⅱ） or platinum （Ⅳ） is exothermic when dtmso is used as an extracting reagent. The coordination number was studied by the slope method. The results indicate that, in high acidity, the dtmso coordination number for extracting gold （Ⅲ） or palladium （Ⅱ） is 3, and that for platinum （Ⅳ） is 2. UV and FT-IR spectra were used to analyze the structure of the complex. Gold （Ⅲ） is coordinated with the oxygen atom in S=O group in dtmso, and palladium （Ⅱ） or platinum （Ⅳ） is coordinated with the sulfur atom in S=O group in dtmso.

The Solvent Effect on the Chemoselectivity of Palladium-catalyzed Oligomerization of 3,3-Dimethyl-1-butyne

The chemoselectivities of PdCl2 and CuCl2-catalyzed oligomerization of 3, 3-dimethyl-butyne: 1, 3, 5-tri-tert-butylbenzene, 2, 2, 7, 7-tetramethyl-3, 6-dichloro-3, 5-octadiene and 2, 2, 7, 7- tetramethyl-3, 5-octadiyne were obtained, respectively, by regulating the polarity of the solvent.

Extraction of Palladium from Acidic Chloride Media into Emulsion Liquid Membranes using LIX 984N-C^®

The extraction of palladium from hydrochloric acid solutions into emulsion liquid membranes (ELMs) using LIX 984N-C as the extractant was investigated. The influential factors and the total capacities of palladium extraction were determined by a batch method. The behavior of palladium extraction by ELMs under the operational conditions-pH of the external feed phase, surfactant and extractant concentration, internal stripping phase concentration, treat ratio and agitation speed were reported. Using LIX 984N-C, palladium was effectively extracted from the external acidic chloride feed phase into the internal receiving phase of W/O emulsions. More than 92% of palladium could be extracted at a feed pH of 2 with 3% Span 80, 9% LIX 984N-C and 7M HCl at a stirring speed of 300 rpm.

KINETIC STUDY ON THE EXTRACTION OF PALLADIUM(Ⅱ) WITH BIS(2-ETHYLHEXYL)SULFIDE

The effects of concentration, temperature, stirring rate and specific interfacial area on the extraction of Pd (Ⅱ) with bis(2--ethylhexyl) sulfide (DEHS) were studied by the use of a constant interracial area cell. The results support an interracial chemical reaction regime.

Solvent Effects on Preparation of Pd-Based Catalysts: Influence on Properties of Palladium and Its Catalytic Activity for Benzyl Alcohol Oxidation

Solvent effects are important for the solution preparation of nanoscale metal materials, in which the sizes and properties of the nanomaterials are greatly influenced by the solvents. In this study, a series of Pd/XC-72 catalysts were synthesized by a facile solvothermal method in solvents with different numbers of hydroxyl groups, including ethanol, ethylene glycol, and glycerine. The as-prepared catalysts Pd/XC-72(EA), Pd/XC-72(EG) and Pd/XC-72(GI) were characterized by XRD, TEM, TGA, ICP-MS and multipoint nitrogen adsorption-desorption experiments. It was found that Pd/XC-72(GI) had the highest metallic dispersion and the smallest particle size (4.9 nm). Furthermore, Pd/XC-72(GI) exhibited the best catalytic performance for solvent-free selective oxidation of benzyl alcohol while the catalytic activities of Pd/XC-72 catalysts decreased in the order: Pd/XC-72(GI) > Pd/XC-72(EG) > Pd/XC-72(EA).

Extraction of Palladium (Ⅱ) with p-Methylphenylalkylsulfide from Aqueous Chloride Media

p-Methylphenylalkylsulfide of various alkyl chain length as extractant were synthesized and the extraction of palladium was examined in terms of equilibrium and kinetics. Distribution ratio of Pd was independent of alkyl chain length. For aqueous chloride media, there was a significant difference in distribution ratios for the solution of NaC1 and HC1. The results of loading test and the slope analysis suggest that the extractant and Pd (Ⅱ) form 2:1 complex. Furthermore, the extraction rate based on the volume of aqueous phase was obtained in a stirred vessel, and the rate equation was presented. Unfortunately, it was difficult to construct surfactant liquid membrane system by use of the present extractant.

A study on the composition and structure of cyclic sulfoxide derivative palladium(Ⅱ) complex

The composition and structure of cyclic sulfoxide derivative Pd(IT) complexwere investigated. The coordinated number was studied with slope method. The coordination number is2 in lower acidity, but it is 3 in higher acidity. Four methods, UV (ultraviolet) spectra, FUR(Fourier transform infrared) spectra, ~1H-NMR (nuclear magnetic resonance) spectra, and ^(13)C-NMRspectra, were used to determine the coordinated atom in complex. Pd is coordinated with O and S atomin S=O group in lower acidity media. The conversion of coordination bond appears with an increasingtime. Pd is coordinated with S atom in S=O group in higher acidity media, and inter-ligand-transferreaction occurs.

Soybean (<i>Glycine Max</i>) Leaf Extract Based Green Synthesis of Palladium Nanoparticles

Palladium (Pd) nanoparticles were synthesized using protein rich soybean leaf extract based biological process. Reduction of palladium ions by soybean leaf extract was examined by UV-visible spectroscopic technique. It was believed that the proteins and some of the amino acids that are exist in soybean leaf extracts were actively involved in the reduction of palladium ions. Further it was confirmed by Fourier transformations infrared spectroscopic (FTIR) analysis. These amino acids are not only involving in the reduction of palladium ions but also acting as surfactants that inhibits the rapid agglomeration. The phase purity of the synthesized palladium nanoparticles was investigated through X-Ray Diffraction (XRD) analysis and the obtained pattern was compared with JCPDS data. Transmission electron microscopic (TEM) images of the palladium particles were recorded and the particle size was found to be ~15 nm.

Insight into the experiment and extraction mechanism for separating carbazole from anthracene oil with quaternary ammonium-based deep eutectic solvents

Carbazole is an irreplaceable basic organic chemical raw material and intermediate in industry.The separation of carbazole from anthracene oil by environmental benign solvents is important but still a challenge in chemical engineering.Deep eutectic solvents (DESs) as a sustainable green separation solvent have been proposed for the separation of carbazole from model anthracene oil.In this research,three quaternary ammonium-based DESs were prepared using ethylene glycol (EG) as hydrogen bond donor and tetrabutylammonium chloride (TBAC),tetrabutylammonium bromide or choline chloride as hydrogen bond acceptors.To explore their extraction performance of carbazole,the conductor-like screening model for real solvents (COSMO-RS) model was used to predict the activity coefficient at infinite dilution (γ^(∞)) of carbazole in DESs,and the result indicated TBAC:EG (1:2) had the stronger extraction ability for carbazole due to the higher capacity at infinite dilution (C^(∞)) value.Then,the separation performance of these three DESs was evaluated by experiments,and the experimental results were in good agreement with the COSMO-RS prediction results.The TBAC:EG (1:2) was determined as the most promising solvent.Additionally,the extraction conditions of TBAC:EG (1:2) were optimized,and the extraction efficiency,distribution coefficient and selectivity of carbazole could reach up to 85.74%,30.18 and 66.10%,respectively.Moreover,the TBAC:EG (1:2) could be recycled by using environmentally friendly water as antisolvent.In addition,the separation performance of TBAC:EG (1:2) was also evaluated by real crude anthracene,the carbazole was obtained with purity and yield of 85.32%,60.27%,respectively.Lastly,the extraction mechanism was elucidated byσ-profiles and interaction energy analysis.Theoretical calculation results showed that the main driving force for the extraction process was the hydrogen bonding ((N–H...Cl) and van der Waals interactions (C–H...O and C–H...π),which corresponding to the blue and green isosurfaces in IGMH analysis.This work presented a novel method for separating carbazole from crude anthracene oil,and will provide an important reference for the separation of other high value-added products from coal tar.

Experimental investigation on coal pore-fracture variation and fractal characteristics synergistically affected by solvents for improving clean gas extraction

Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction efficiency.However,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully understood.Ultrasonic testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal theory.Relationship model between permeability,fractal dimension and porosity were established.Results indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to 1.4767.Maximum decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,respectively.Solvent treatments could lead to increasing amount of both mesopores and macropores.Decrease ratio of fractal dimension Dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to 6.4486.Meanwhile,combined solvent could dissolve coal polar and non-polar small molecules and expand flow space.Results could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.

Study on the green extraction of corncob xylan by deep eutectic solvent

Corn as one of the world's major food crops,its by-product corn cob is also rich in resources.However,the unreasonable utilization of corn cob often causes the environmental pollution,waste of resources and other problems.As one of the most abundant polymers in nature,xylan is widely used in food,medicine,materials and other fields.Corn cob is rich in xylan,which is an ideal raw material for extracting xylan.However,the intractable lignin is covalently linked to xylan,which increases the difficulty of xylan extraction.It has been reported that the deep eutectic solvent(DES)could preferentially dissolve lignin in biomass,thereby dissolving the xylan.Then,the xylan in the extract was separated by ethanol precipitation method.The xylan precipitate was obtained after centrifugation,while the supernatant was retained.The components of the supernatant after ethanol precipitation were separated by the rotary evaporator.The ethanol,water and DES were collected for the subsequent extraction of corn cob xylan.In this study,a novel way was provided for the green production of corn cob xylan.The DES was used to extract xylan from corn cob which was used as the raw material.The effects of solid-liquid ratio,reaction time,reaction temperature and water content of DES on the extraction rate of corn cob xylan were investigated by the single factor test.Furthermore,the orthogonal test was designed to optimize the xylan extraction process.The structure of corn cob xylan was analyzed and verified.The results showed that the optimum extraction conditions of corn cob xylan were as follows:the ratio of corn cob to DES was 1:15(g:mL),the extraction time was 3 h,the extraction temperature was 60℃,and the water content of DES was 70%.Under these conditions,the extraction rate of xylan was 16.46%.The extracted corn cob xylan was distinctive triple helix of polysaccharide,which was similar to the structure of commercially available xylan.Xylan was effectively and workably extracted from corn cob by the DES method.This study provided a new approach for high value conversion of corn cob and the clean production of xylan.

Liquid Etherification of Alkoxybenzyl Alcohols, Cinnamyl Alcohols and Fluorinated Phenylalkenols with Platinum on Carbon (Pt/C) and Palladium on Carbon (Pd/C)

In the presence of either Pd/C or Pt/C, 4-alkoxybenzyl alcohols, 4-alkoxy-phenylalkyl alcohols and cinnamyl alcohols undergo liquid etherification to bis(4-alkoxybenzyl) ethers, bis[(4-alkoxybenzyl)alkyl] ethers and bis(cin-namyl) ethers at temperatures of 100°C - 135°C. In a number of cases, Pt/C and Pd/C as catalysts, also when they are doped with Ru, show distinct differences when the reactions run in air, with an oxidative dehydrogenation of the alcohols as side-reaction, yielding the corresponding ketones and aldehydes as by-products. Also, the reactivity of fluorinated phenylalkenols under these conditions has been investigated. Furthermore, the immobilization of alkyl aryl ethers on silica within a column with passage of hexane as solvent was found to lead to the formation and elution of styrenes from the column in fair yield.

Mechanism of extracting palladium(Ⅱ) with cyclic sulfoxide derivatives

The extraction ability of palladium(Ⅱ) from acidic media with cyclic sulfoxide derivatives-α Dodecyl tetrahydrothiophene 1 Oxide (DTMSO), α octyl tetrahydrothiophene 1 Oxide (OTMSO) and α butyl tetrahydrothiophene 1 Oxide (BTMSO) was investigated. The extracting efficiency of cyclic sulfoxide derivatives decreased with the increasing of acidity in the lower acidity, and the efficiency became stable with the change of acidity in the higher acidity. The extraction reaction of palladium(Ⅱ)with DTMSO is exothermic, and extraction reaction of palladium(Ⅱ)is endothermic when OTMSO or BTMSO were used as extracting reagents. The coordination number was studied by slope method. The results indicate that coordination number is 2, and the composition of complex is (PdCl 2)·2RTMSO. FT IR spectra were used to analyze the structure of complex and coordinated atom in complex, Pd is coordinated with both oxygen and sulfur atom in S=O group in sulfoxide derivatives.

Predictive methods for density and refractive index of naphthenic lubricating oils during solvent extraction process

Lubricating oils are usually produced by solvent extraction to separate aromatics in order to achieve the desired specifications and better quality products.Among the different properties of lubricating oils,density and refractive index are some of the most important properties which can both be used for petroleum fluid characterization.Predictions of density and refractive index for naphthenic oils during solvent extraction by DMSO obtained by the pseudo-component approach and the quadratic correlation were both examined.The pseudo-component approach is a method to predict density and refractive index from composition while the latter merely relates density to refractive index.Results indicated that the predictions yielded by the pseudo-component method were in good agreement with experimental data for naphthenic oils.And the use of a function of refractive index(FRI_(20))as a pseudo-component property remarkably improved n_(20)predictions for the naphthenic mixtures.However,the density and refractive index predictions obtained by the quadratic correlation exhibited significantly higher de-viations for naphthenic oils than those for paraffinic oils.Thus a new modified correlation of the same functional form was proposed for naphthenic oils.The modification significantly improved predictions for naphthenic oils,which presented similar accuracy as the pseudo-component approach.And the previous correlation was still used for paraffinic oils.Additionally,effect of temperature on density and refractive index of naphthenic oils was examined.Results showed that the modified quadratic correlation was accurate for describing the relationship between density and refractive index of naphthenic oils at 20-90℃.The temperature dependence of density and refractive index for the raffinates and the extracts could be accurately described by the thermal coefficients for saturates and aromatics,respectively.Regarding the refractive index variation of the extracts with temperature,the empirical equation was proved to be a better option compared with the method using the thermal coefficient for aromatics.

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.

Liquid–liquid extraction of levulinic acid from aqueous solutions using hydrophobic tri-n-octylamine/alcohol-based deep eutectic solvent

Levulinic acid(LA)is one of the top-12 most promising biomass-based platform chemicals,which has a wide range of applications in a variety of fields.However,separation and purification of LA from aqueous solution or actual hydrolysate continues to be a challenge.Among various downstream separation technologies,liquid-liquid extraction is a low-cost,effective,and simple process to separate LA.The key breakthrough lies in the development of extractants with high extraction efficiency,good hydrophobicity,and low cost.In this work,three hydrophobic deep eutectic solvents(DESs)based on tri-n-octylamine(TOA)as hydrogen bond acceptor(HBA)and alcohols(butanol,2-octanol,and menthol)as hydrogen bond donors(HBDs)were developed to extract LA from aqueous solution.The molar ratios of HBD and HBA,extraction temperature,contact time,solution pH,and initial LA concentration,DES/water volume ratios were systematically investigated.Compared with 2-octanol-TOA and menthol-TOA DES,the butanol-TOA DES exhibited the superior extraction performance for LA,with a maximum extraction efficiency of 95.79±1.4%.Moreover,the solution pH had a great impact on the LA extraction efficiency of butanol-TOA(molar ratio=3:1).It is worth noting that the extraction equilibrium time was less than 0.5 h.More importantly,the butanol-TOA(3:1)DES possesses good extraction abilities for low,medium,and high concentrations of LA.