Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m2·g-1 and 5.18 mmol·g-1, respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with-SO3 H in resin. The removal process was studied as a function of temperature, H3 PO4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g-1 resin when the operating parameters were T = 50 ℃, H3 PO4 content = 27.61 wt%and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol-1. The overall reaction process was mainly controlled by pore diffusion.

Adsorption behavior and mechanism of cadmium on strong-acid cation exchange resin

The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.

Adsorption equilibrium, kinetics, and dynamic separation of Ca2+ and Mg2+ ions from phosphoric acid–nitric acid aqueous solution by strong acid cation resin

The separation of Ca2+and Mg2+ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer.This paper studied the adsorption equilibrium,kinetics,and dynamic separation of Ca2+and Mg2+ions by strong acid cation resin,and the effects of phosphoric acid and nitric acid on the adsorption process were investigated.The results reveal that the adsorption process of Ca2+and Mg2+ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g-1 and 1.83 mmol·g-1,respectively.The adsorption kinetics of Ca2+and Mg2+ions on resin fits better with the pseudo-first-order model,and the adsorption equilibrium in pure water is reached within 10 min contact time,while at the present of phosphoric acid,the adsorption rate of Ca2+and Mg2+ions on resin will go down.The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution,but the dynamic operation should control the flow rate of mix acid solution.Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.

Kinetic Modeling of Esterification Reaction of Free Fatty Acids Present in Macauba Oil Using a Cationic Resin as Catalyst

The cost of raw materials has the largest contribution to the final price of biodiesel produced by traditional routes, currently adopted in most industrial scale processes. That contribution comes from the need to use edible and noble oils, with low acidity, such as soybean oil. This work proposes＇the use of Macauba oil, a vegetable oil in focus in the State of Minas Gerais, Brazil, in which the current extractive yield generates a raw material with high acidity, therefore, not suitable to be used in biodiesel production. To make it technically feasible, a cationic exchange resin, the Purolite CT275DR, was used as a catalyst for esterification reaction with samples of Macauba oil, aiming to reduce its acidity. The resin can be reused, regenerated and easily removed from the reaction product, reducing costs with catalyst and purification stages. As a result of this work, in a sample of oil with an initial acidity of about 10% m/m were achieved acidity reductions up to 97% by using cationic resins as catalyst, demonstrating its potential use in the oil pretreatrnent step. Additionally, the data collected during all the analysis made it possible to define the chemical kinetic of the esterification reaction.

USE OF CATION EXCHANGE RESIN IN SYNTHESIS OF N-SUBSTITUTED-1-AMINOALKANEPHOSPHONATE AND-PHOSPHINIC ACIDS

Strongly acidic cation exchange resin(1x1,H form)has been successfully used as a catalyst in synthesis of diphenyl N-benzyloxycarbonyl-1-aminobenzylphosphonate, N-benzyloxycarbonyl-1-aminobenzylphenylphosphinic acid and N-p-tolylsulfonyl-1-aminobenzyl phenylphosphinic acid in high yields.

三羟甲基丙烷棕榈油酸酯的合成及其润滑性能研究

为替代矿物基润滑油,制备出稳定性好、易降解、环境友好的植物油基润滑油,采用天然产物棕榈油酸,以三羟甲基丙烷为原料,酸性阳离子树脂Amberlyst为多相催化剂制备润滑剂三羟甲基丙烷棕榈油酸酯(TMPTO),研究了制备条件对TMPTO酯化率的影响,并筛选出最佳合成参数。测试了TMPTO的运动黏度、黏度指数、闪点等物理性质,采用NMR、FTIR、DSC、TG对TMPTO的结构和热氧化稳定性进行了表征;采用四球试验机、接触角测量仪、XRF对TMPTO的抗磨损性能、润湿性和防铝腐蚀性能进行了测试。结果表明:在反应温度180℃,真空度0.09 MPa,醇酸摩尔比1.0∶3.1,反应时间5 h,催化剂用量0.2%(质量分数)的条件下,棕榈油酸的酯化率达到81.53%,催化剂重复使用4次后的酯化率仍保持在81.15%。制备的三羟甲基丙烷棕榈油酸酯的酸值仅为1.87 mg KOH/g,具有较高的闪点(238℃),具有优异的防铝腐蚀性能、润湿性、热氧化稳定性和极压抗磨性能:最大无卡咬负荷P_B为88 kg,最大烧结负荷P_D为620 kg。

The composition of acid/oil interface in acid oil emulsions

In well stimulation treatments using hydrochloric acid,undesirable water-in-oil emulsion and acid sludge may produce and then cause operational problems in oil field development.The processes intensify in the presence of Fe(Ⅲ),which are from the corroded surfaces of field equipment and/or iron-bearing minerals of the oil reservoir.In order to understand the reasons of the stability of acid emulsions,acid emulsions were prepared by mixing crude oil emulsion with 15% hydrochloric acid solutions with and without Fe(Ⅲ) and then separated into free and upper(water free) and intermediate(with water) layers.It is assumed that the oil phase of the free and upper layers contains the compounds which do not participate in the formation of acid emulsions,and the oil phase of the intermediate layers contains components involved in the formation of oil/acid interface.The composition of the oil phase of each layer of the emulsions was studied.It is found that the asphaltenes with a high content of sulfur,oxygen and metals as well the flocculated material of protonated non-polar oil components are concentrated at the oil/acid interface.In addition to the above,in the presence of Fe(Ⅲ) the Fe(Ⅲ)-based complexes with polar groups of asphaltenes are formed at the acid/oil interface,contributing to the formation of armor films which enhance the emulsion stability.

DK-13和DK-3两种大孔弱酸阳离子树脂提取西索米星的吸附热力学和动力学研究

目的采用静态吸附实验考察了DK-13、DK-3两种大孔弱酸阳离子树脂对西索米星的吸附热力学和动力学行为。方法用刚果红分光光度法测定不同温度和不同初始浓度下的吸附等温线和吸附动力学、热力学曲线等。结果两种树脂对西索米星的吸附过程符合Langmuir吸附等温方程(R2>0.998)和拟二级动力学模型(R2>0.995);热力学参数计算结果显示,吉布斯自由能变ΔG、焓变ΔH、熵变ΔS均大于零,说明其吸附过程为非自发吸热的熵增过程。同时,研究还发现DK-13树脂交换带长度为DK-3的5.2倍,表明DK-13树脂适用于固定床而DK-3树脂用于连续离子交换床更有利。结论本研究结果为大孔弱酸阳离子树脂吸附提取西索米星工艺的工业化应用提供了理论指导。

阳离子交换树脂分离-电感耦合等离子体发射光谱(ICP-OES)法测定盐湖卤水中偏硅酸含量

由于盐湖卤水中盐分浓度不同且盐度较高,采用常规分析方法很难准确测定。通过对阳离子交换树脂加入量、阳离子交换树脂交换时间、pH值对交换效率的影响、内标元素校正的考察,建立了阳离子交换树脂分离-电感耦合等离子体发射光谱法测定盐湖卤水中偏硅酸含量的方法。将盐湖卤水稀释5倍,加入6 g阳离子交换树脂,静态交换1.5 h,除去卤水中的大量阳离子后,选择Si 251.611 nm为分析谱线,以Y 371.030 nm谱线作为内标进行信号漂移校正,用电感耦合等离子体发射光谱仪能有效测定卤水中偏硅酸的含量。结果表明,校准曲线的线性范围为0.50~200 mg/L,所得回归方程的线性关系良好(r≥0.9994),检出限为0.16 mg/L,结果相对标准偏差(RSD,n=12)为1.8%~4.6%,加标回收率为96.3%~102%。同时采用紫外-可见分光光度法对偏硅酸含量进行方法比对,两种测试结果不存在显著性差异,表明所建立的方法具有良好的准确度。为提高盐湖资源的综合利用提供了可靠的数据支撑。

阳离子交换树脂催化合成新戊二醇过程研究

利用催化精馏技术,以2,2-二甲基-1,3-环氧丙烷为原料,强酸性阳离子交换树脂为催化剂,在催化精馏塔中进行催化水解反应合成新戊二醇,考察了温度、液空速、油水相比、催化剂的稳定性等因素对水解工艺结果的影响。采用N2吸附脱附、NH_(3)-TPD、FT-IR光谱、XPS光谱、TG、XRD、交换容量等表征手段对强酸性阳离子交换树脂的内部结构和元素价态进行分析,研究结果表明:强酸性阳离子交换树脂具有优异的催化性能,在温度为80℃,油水比(相比)为1∶4的条件下,新戊二醇的收率可达94.31%,连续运行200 h后,催化剂的稳定性能仍然良好,具有良好的工业应用前景。

电子用双环戊二烯苯酚树脂的绿色合成及表征

本文以双环戊二烯(DCPD)和苯酚为原料,以自制的新型强酸性阳离子交换树脂为烷基化反应的催化剂,催化苯酚与DCPD发生反应生成双环戊二烯苯酚树脂(DPR)。用阳离子交换树脂替代传统含氟催化剂作为烷基化反应的催化剂,减少了含氟废水的产生,更加绿色环保。通过改变反应时间、反应温度、原料配比、催化剂用量以及正交实验,探究烷基化反应的最佳工艺条件以及阳离子交换树脂磺化度对产物的影响,使合成的树脂能够符合电子用树脂的要求。同时探究DPR树脂的结构,并测定DPR树脂中不同聚合度组分的含量,以及DPR树脂的软化点、收率等数据。实验表明,当采用新型强酸性阳离子交换树脂为催化剂,反应条件为3 h、120℃,原料配比为4∶1,催化剂用量为20%时,聚合度为0的组分含量可达92.36%。

SCX-SPE结合UHPLC-Q-Exactive Orbitrap MS分析草乌中的四类二萜生物碱

目的对草乌中的二萜生物碱进行表征分析。方法以强酸性阳离子交换树脂固相萃取(SCX-SPE)分离纯化草乌中的二萜生物碱,并结合超高效液相色谱串联四极杆静电场轨道阱质谱(UHPLC-Q-Exactive Orbitrap MS)进行结构鉴定。结果结合精确分子质量、多级质谱裂解规律、对照品对比、Clog P值及文献报道,共从草乌中鉴定了99个二萜生物碱类成分,包括双酯型二萜生物碱(DDA)27个,单酯型二萜生物碱(MDA)29个,酰胺型二萜生物碱(ADA)40个,多酯型二萜生物碱(PDA)2个,以及长链型二萜生物碱(LDA)1个。结论本文所建立的SCX-SPE结合UHPLC-Q-Exactive Orbitrap MS方法能快速地鉴定草乌中的二萜生物碱类成分,可为草乌的药效物质基础及质量控制研究提供科学依据。

阳离子树脂催化乳酸与甲醇反应动力学

在酯化水解法提纯乳酸的生产过程中,酯化反应动力学的研究对该工艺具有非常重要的意义。以ZGC108酸性阳离子交换树脂为催化剂,在间歇釜搅拌釜式反应器中对乳酸和甲醇的酯化反应本征动力学进行研究。探究搅拌速率、催化剂用量、醇酸摩尔比、反应温度对反应过程的影响。得出最佳反应条件为转速500 r/min、催化质质量占反应液体总质量的3%、醇酸摩尔比3∶1、反应温度343.15 K。采用拟均相模型对实验数据进行关联,建立反应动力学模型。通过反应速率的验证,该模型合理地预测了动力学实验数据。

Cansolv废酸水再生阳离子交换树脂实验研究

Cansolv尾气氧化工艺运行过程中会产生较大量废酸水(含SO_(3)^(2-)、SO_(4)^(2-)),一般采用31%盐酸对生产废水装置阳离子交换树脂进行再生。为了研究Cansolv废酸水替代盐酸再生阳离子交换树脂效果,实验通过对001-7阳离子交换树脂进行静态及动态吸附、废酸水对吸附后树脂进行再生脱附,测定树脂吸附率(η%)及脱附率(P%)。实验结果表明,阳离子交换树脂对Ca^(2+)和Mg^(2+)均具有良好的吸附效果,废酸水作为脱附液进行树脂再生可行;动态吸附时阳离子交换树脂对Mg^(2+)和Ca^(2+)最大吸附率可达70%和50%,动态吸附最佳上柱流速为3 mL/min;废酸水作为洗脱液对2种离子均具有一定的洗脱能力,Mg^(2+)和Ca^(2+)的脱附率分别为81.9%和48.6%,且质量浓度为4%为洗脱液的最佳浓度。

海参酶解液中重金属铬的脱除

海参酶解液主要成分为海参多肽,海参多肽具有抗菌、抗病毒、抗肿瘤等活性,在多领域有着广阔的应用前景,但重金属污染是海参多肽应用过程中潜在的危害,对海参酶解液中的重金属脱除变得尤为重要。研究选用树脂法、壳聚糖及其衍生物法、络合法中的7种脱除材料对海参酶解液中的重金属铬进行脱除,结果表明,732型阳离子交换树脂、壳聚糖和植酸分别是3种脱除方法中的最佳脱除材料。经过正交试验与验证试验显示,732型阳离子交换树脂在实验条件为酶解液pH 6、脱除温度15℃、脱除剂添加量1 g、脱除时间2 h下,铬脱除率为(87±1.86)%,多肽保留率为(90±2.69)%,很好的脱除海参酶解液中的重金属铬,并能保留大部分多肽。该实验为高蛋白含量海洋动物酶解液中脱除重金属铬提供了参考。

强酸性阳离子交换树脂对铅的吸附行为及机理

通过静态吸附实验,研究了Pb2+在001×7强酸性阳离子交换树脂上的吸附行为,并从热力学和动力学方面对吸附过程进行了分析,用红外光谱的方法探讨了001×7树脂吸附Pb2+的机理。结果表明:在所研究的浓度范围内,Pb2+在001×7树脂上的吸附平衡数据符合Freundlich等温吸附方程,吸附为自发进行的放热过程;液膜扩散为Pb2+在001×7树脂上吸附速率的主要控制步骤,随着振荡频率的增加,吸附速率会逐渐增大;最佳的吸附pH在4左右,用3mol/L的硝酸对饱和树脂进行洗脱再生,洗脱率可达98%以上;298K温度下树脂的静态饱和吸附容量为414mg/g(湿树脂)。

丙烯酸高级醇酯合成工艺的研究

以大孔强酸性阳离子交换树脂为催化剂 ,对羟基苯甲醚作阻聚剂 ,合成了丙烯酸 C8～ C16 正构偶数碳醇酯。实验结果表明 ,D0 0 1cc树脂具有良好的催化活性和稳定性 ,丙烯酸酯收率达 94

阳离子交换树脂催化合成丙烯酸环己酯

以丙烯酸和环己烯为原料,磺酸基苯乙烯系强酸性阳离子交换树脂为催化剂合成丙烯酸环己酯,考察了反应温度、催化剂用量、烯酸摩尔比、反应时间对酯化反应的影响。结果表明,合成丙烯酸环己酯的最佳条件为:反应温度85℃,催化剂质量分数5%,n(酸)∶n(烯)=2∶1,反应时间5 h。在最佳工艺条件下,环己烯转化率为87.2%,丙烯酸环己酯选择性90.1%,二聚物选择性8.7%。

离子交换色谱法分离氨基酸实验方法的改进

离子交换色谱法分离氨基酸实验经过改进后,选用具有易洗脱特点的D61阳离子交换树脂代替原实验中的001×7树脂,洗脱液由原来的NaCl溶液改为NaOH溶液。改进后的实验方法优化了氨基酸的分离效果,节省了实验时间,能够很好地适应基础生物化学实验教学的课程特点。