Liquid-Liquid Equilibrium Study of Phenol Extraction with Cyanex 923

Abstract

Although phenol extraction with Cyanex 923 has widely been studied, liquid-liquid equilibrium between phenol and undiluted Cyanex 923 has not been thoroughly investigated. Many factors influence the phenol extraction with undiluted Cyanex 923. Increasing the phenol concentration causes a water molecule replacement in the extractant by phenol molecules. Increasing the pH value above 12 decreases the phenol distribution coefficient K_D by 99.9%. A temperature increase from 15°C to 65°C results in a K_D decrease of 70%. With increasing salt content K_D increases due to salting-out. Adding organic acids stabilizes phenol in the aqueous phase and obstructs the extraction.     

萃取置换法回收处理氟苯生产废水中的苯酚

以磷酸三丁酯(TBP)为萃取剂、NaOH水溶液为反萃剂,采用萃取置换法回收处理氟苯生产废水中的苯酚.研究了萃取剂浓度、萃取时间、pH值及相比对萃取率的影响和相比、反萃时间及NaOH溶液浓度对反萃率的影响.经3级萃取和2级反萃取,苯酚的回收率达98%,废水中苯酚含量可降至19.7 mg/L.萃取置换法操作简单,费用低廉,易于工业化.     

煤气化废水酚氨分离回收系统的流程改造和工业实施

煤气化工艺中产生的洗气废水含有酚氨等高浓度难降解有机污染物。工业上采用化工分离和生化处理两段法来依次实现回收酚氨和净化排放。现有工艺中酚回收效率较低,难以保证进入生化工艺段的水质,影响最终排放。本文研究发现:萃取剂的选择和分离序列对萃取过程的pH值及随之对脱酚效率的影响极大。本文将脱氨装置单元前置,提出了精馏汽提塔侧线脱氨技术,将废水的pH值从10.5降到6.5,使萃取在偏酸条件下进行。采用甲基异丁基甲酮(MIBK)替代原有的二异丙醚(DIPE)萃取剂,显著提高了对多元酚的分配系数,总酚萃取效率从76%提升到93%。以上新流程已在某大型煤化工企业3200t.d-1煤气化污水化工分离系统中得以成功改造实施。新流程的实施提高了有机污染物的脱除率,为后续的生化处理工艺的达标排放奠定了基础。     

Recovery of hydrochloric acid from galvanizing industrial effluents

The recovery of hydrochloric acid and its separation from iron, zinc and minor elements, in the galvanizing pickling baths, were studied by solvent extraction (SX) and distillation and by distillation and crystallization. Several extractants were tested, the tri-isooctyl amine, Alamine 308, the primary aliphatic amine Primene JM-T and the mixture of four trialkylphosphine oxides, Cyanex 923. Only Cyanex 923 enabled distillation. The results indicated the feasibility of the processes to treat a real effluent using Cyanex 923 and to obtain high HCl concentrations in the distillate (256–330 g/L).     

Modelling of resol resin polymerization with various formaldehyde/phenol molar ratios

The kinetics of polymerization of phenol and formaldehyde are modelled to account for the formation of resol resin with various initial formaldehyde/phenol molar ratios. The conversion of phenol and formaldehyde is used to determine the equilibrium constants for phenolate ion and methylene glycol. The relative concentration of each compound is obtained as a function of time. The molecular weight is also determined for each resol resin at the end of the reaction. The evaluation of substituted phenols, hydroxymethylol phenols and methylene bridges was carried out by infrared spectroscopy. The experimental tendencies are in agreement with the results of the model. © 2001 Society of Chemical Industry     

Comparative study of the determination of platinum by extraction with Cyanex 923 and Cyanex 471X from bromide media

The extraction equilibrium study of Pt(IV) was carried out with Cyanex 923 and Cyanex 471X in toluene from hydrobromic acid media to investigate their extraction capacity, since they have different donor atoms, ‘O’ and ‘S’. Their distribution equilibria were studied as a function of extractant concentration, diluents, hydrobromic acid concentration and the effect of temperature on extraction. Pt(IV) was quantitatively extracted with 0.1 mol dm^?3 Cyanex 923 in toluene from 5.0–8.0 mol dm^?3 HBr media and was stripped with 4.0 mol dm^?3 perchloric acid. However it was also quantitatively extracted with 0.1 mol dm^?3 Cyanex 471X (with 0.1 mol dm^?3SnCl₂) in toluene from 6.0–8.0 mol dm^?3 HBr media and was stripped with 1.0 mol dm^?3 stabilized sodium thiosulfate solution at pH 9.0. The slope analysis method indicated metal complex species of 1:1 for Pt(IV) with Cyanex 923 and Cyanex 471X in toluene from HBr media. These methods were successfully applied to the analysis of platinum in real samples. © 2001 Society of Chemical Industry     

杉木液化产物用于胶粘剂制备的研究

研究用少量的苯酚液化木材及其产物用于胶粘剂制备的方法,在硫酸催化剂作用下,用苯酚液化杉木木粉,得到木材液化产物.在液化产物中加入适量的甲醛和氢氧化钠溶液制备热固性酚醛树脂.压板测试结果表明,由木材液化产物所得树脂的干状胶合强度令人满意,但经蒸汽循环试验后,湿状胶合强度尚达不到JAS标准的要求,在下阶段工作中,需进一步研究木材液化产物胶粘剂的改性以提高其胶合耐久性.     

Investigation of liquid–liquid phase equilibria for reactive extraction of lactic acid with organophosphorus solvents

BACKGROUND: Lactic acid is a versatile commodity chemical with a variety of applications. Synthesis of lactic acid either through fermentation of carbohydrates or through chemical synthesis is state of the art. Separation from dilute aqueous solution is complex and accounts for the major part of production costs. Reactive extraction based on reversible adduct formation is a promising alternative for the separation of lactic acid. RESULTS: Extraction was carried out with the organophosphorus solvents tri‐n‐butyl phosphate, tri‐n‐octylphosphine oxide and Cyanex 923. Shellsol T was used as diluent. Partition coefficients increase with increasing extractant content and decreasing temperature. Cyanex 923 has several advantages compared with tri‐n‐butyl phosphate and tri‐n‐octylphosphine oxide with respect to lactic acid distribution and hydrodynamic properties. Liquid‐liquid phase equilibria for lactic acid extraction with Cyanex 923 were modeled. Selectivity of lactic acid extraction with respect to glycolic acid and formic acid was discussed. CONCLUSION: The organophosphorus extractant Cyanex 923 was found to be an appropriate solvent for lactic acid extraction from aqueous solutions. Experimental data and model data based on the Law of Mass Action showed good agreement. Lactic acid extraction from multi‐acid solution showed good selectivity compared with glycolic acid. Lactic acid selectivity is low with respect to formic acid. © 2012 Society of Chemical Industry     

Modelling of the extraction equilibrium of zinc from chloride solutions with tri-n-octylphosphine oxide

The extraction of zinc from chloride solutions with tri-n-octylphosphine oxide (TOPO) dissolved in benzene has been thermodynamically studied based on the law of mass action. A model employing the simplified Pitzer equations for stoichiometric activity coefficient estimations is found to be effective for the explanation and prediction of the distribution data, and the thermodynamic extraction constant is determined as log K_et = 5.16 ± 0.11 at 20°C.     

Kinetic study of ytterbium(III) extraction from sulfate medium with Cyanex 923

The kinetics of ytterbium(III) extraction from sulfate medium with Cyanex 923 in heptane has been investigated with a constant interfacial cell with laminar flow, which aimed to identify the extraction regime, reaction zone and rate equations. It was found that the extraction rate of ytterbium(III) increased linearly with stirring speed and specific interfacial area. The activation energy E_a (9.56 kJ mol^?1), activation enthalpy ΔH^± (7.05 kJ mol^?1), activation entropy ΔS^±₂₉₈ (?0.31 kJ mol^?1) and Gibbs free energy of activation ΔG^±₂₉₈ (98.3 kJ mol^?1) were calculated from the dependence of extraction rate on temperature. The experiential rate equations were obtained by investigating the influence of the concentration of various species on the extraction rate. A diffusion regime has been deduced from evidence of the linear dependence of extraction rate on stirring speed and the low value of the activation energy. The liquid–liquid interface is most probably the reaction zone in view of the linear dependence of extraction rate on specific interfacial area, the high interfacial activity and low water‐solubility of extractant. Thus the mass transfer rate is controlled by interfacial film diffusion of species. Copyright © 2007 Society of Chemical Industry     

煤化工废水萃取脱酚流程模拟

为提高煤化工高浓度含酚废水萃取脱酚的处理效果,减轻废水排放环境污染,采用Aspen Plus流程模拟软件对煤化工废水萃取脱酚流程进行了优化设计。模拟采用真实煤化工废水的组成设置物流数据,废水进料流量为100 t/h,温度为40℃,压力为0.1 MPa,并利用UNIQUAC和NRTL活度系数模型,分别对萃取脱酚塔、溶剂回收塔、溶剂汽提塔进行了参数调整。模拟结果表明,当萃取脱酚塔萃取级数n=6,萃取相比R=1∶4时;溶剂回收塔的理论塔板数N=10,进料位置为第5块塔板时;溶剂汽提塔的理论塔板数N=5,进料位置为第1块塔板时,废水总酚浓度从18 600 mg/L降至400mg/L以下,单元酚浓度从14 000 mg/L降低至50 mg/L以下,萃取剂回收利用率达到99%以上。     

Opposite selectivities of tri-n-butyl phosphate and Cyanex 923 in solvent extraction of lithium and magnesium

The synergic solvent extraction system of tri-n-butyl phosphate (TBP) and FeCl₃ (or ionic liquids, ILs) has been extensively studied for selective extraction of Li from Mg-containing brines. However, Cyanex 923 (C923), which extracts many metals stronger than TBP, has not yet been examined for Li/Mg separation. Here, we report on the unexpected observation that the C923/FeCl₃ system has opposite Li/Mg selectivity compared to the TBP/FeCl₃ system. Detailed investigations show that the opposite selectivity of the C923/FeCl₃ (or IL) system is due to three factors: (1) the strong extraction of Fe by C923 leads to a low concentration of [FeCl₄]⁻ in the system, which is essential for Li extraction; (2) C923 in combination with an IL extracts Mg strongly by an ion-pair mechanism; (3) most importantly, C923 extracts Mg by solvation, resulting in an insufficient concentration of C923 for Li extraction. The unexpected poor Li/Mg selectivity of C923 highlights the irreplaceable role of TBP in the selective recovery of Li.     

多羟甲基苯酚的合成工艺研究

以苯酚和甲醛为原料，在催化剂存在下经羟甲基化制备多羟甲基苯酚。羟甲基化反应的较佳合成工艺条件为：摩尔比1：3.5、甲醛溶液浓度30％、反应温度30℃、反应时间40h、以丙酮为沉降剂。     

Extraction of Lanthanum and Samarium from Nitrate Medium by some Commercial Organophosphorus Extractants

Abstract

The extraction of lanthanum(III) and samarium(III) from nitrate solutions by some phosphine oxide compounds (Cyanex 921, Cyanex 923, and Cyanex 925) in kerosene was investigated. The influence of the different factors affecting the extraction was studied in detail. The extraction of these metals using the above extractants was compared and the sequence of extraction was found to be Cyanex 921>Cyanex 923?Cyanex 925. The stripping percent of La(III) and Sm(III) by 0.75 M HNO₃ from the loaded organic phase after two stages were 72% and 5.2%, respectively, which could enable a good separation between these two lanthanides.     

Kraft lignin in phenol formaldehyde resin. Part 1. Partial replacement of phenol by kraft lignin in phenol formaldehyde adhesives for plywood

The objective of this study was to investigate the potential for partially replacing phenol with kraft lignin in the phenol formaldehyde (PF) resin designed for application as an adhesive in the production of plywood. The kraft lignin, considered to be an environmentally friendly alternative to phenol, was precipitated from black liquor recovered from kraft pulping of softwood. Kraft lignin phenol formaldehyde (KLPF) resin was prepared in a one-step preparation with different additions of lignin. Replacing 50 wt% of the phenol with kraft lignin (50KLPF) was, under the conditions used, considered to be optimal with respect to resin viscosity, storage stability, and bonding ability. The resin consists of an integrated kraft lignin-phenol network. The hot-pressing time in the plywood manufacturing had to be increased by approximately 30% at 150°C for the 50KLPF resin compared with that normally used for PF resin, in order to comply with plywood standard demands. The mechanical properties of test samples made from KLPF resins were equal to or better than those of test samples made from PF resin only.     

酚醛废水预处理工艺优化的试验研究

以某酚醛树脂厂的生产废水为对象，采用尿素－苯酚－甲醛碱性缩合预处理工艺，基于均匀设计和回归分析，建立了多元回归模型，研究了配比、催化剂、反应时间及温度等因素对处理效果的影响，优化了预处理的工艺条件，酚、醛去除率分别可达99．8％、99．2％，出水可满足进一步进行生化处理的要求，并可回收苯酚改性脲醛树脂。同时，还为提高酚醛树脂合成产率提供了有效的优化思路，可从根本上降低树脂厂生产废水中酚、醛的污染程度。     

Solvent extraction of Zn(II) by Cyanex 923 and its application to a solid‐supported liquid membrane system

The extraction of zinc(II) by Cyanex 923 (phosphine oxides mixture) in Solvesso 100 from hydrochloric acid solution has been investigated. The extraction reaction is exothermic. The numerical analysis of metal distribution data suggests the formation of ZnCl₂·L₂,HZnCl₃·2L and H₂ZnCl₄·2L(L = ligand) in the organic phase with formation constants K_ext = 4.1,5.6 × 10⁹ and 6.7 × 10⁹, respectively. The results obtained for zinc(II) distribution have been implemented in a solid‐supported liquid membrane system. The influence of source phase stirring speed, membrane composition and metal concentration on zinc transport have been investigated. © 2001 Society of Chemical Industry     

Liquid–liquid extraction of cadmium(II) by Cyanex 923 and its application to a solid‐supported liquid membrane system

The extraction of cadmium(II) by Cyanex 923 (a mixture of alkylphosphine oxides) in Solvesso 100 from hydrochloric acid solution has been investigated. The extraction reaction is exothermic. The numerical analysis of metal distribution data suggests the formation of CdCl₂.2L, HCdCl₃.2L and H₂CdCl₄.2L (L = ligand) in the organic phase. The results obtained for cadmium(II) distribution have been implemented in a solid‐supported liquid membrane system. The influences of feed phase stirring speed (400–1400 min^?1), membrane composition (carrier concentration: 0.06–1 mol dm^?3) and metal concentration (0.01–0.08 g dm^?3) on cadmium transport have been investigated. Copyright © 2005 Society of Chemical Industry     

甲醛/苯酚配比对可发性甲阶酚醛树脂性能的影响研究

以苯酚、多聚甲醛、甲醛溶液为原料,NaOH为催化剂,采用逐步共聚的聚合工艺,制备可发性甲阶酚醛树脂,采用环保型发泡剂、匀泡剂、实验室自制复合酸固化剂制备阻燃保温酚醛泡沫材料。研究了甲醛/苯酚配比(物质的量之比即F/P)进行单因素分析,对可发性甲阶酚醛树脂的物理性能、有毒物质残余量、分子结构和活性的影响以及与树脂可发性的关系。结果表明,当F/P=2.0时,可发性甲阶酚醛树脂的粘度为2 680 mPa.s,游离甲醛含量为0.75%,游离苯酚含量为2.3%,羟甲基含量为34.83%,泡沫表观密度为0.050 7 g/cm3。