Industrial utilization of C21 dicarboxylic acid

Interest in polyfunctional materials has increased steadily in recent years as polymer systems have become more prevalent in our society. One of the more unique and versatile of these products has only recently become commercially available, 5(6)-carboxy-4-hexyl-2-cyclohexene-1-octanoic acid. This C₂₁ dicarboxylic acid not only has the expected ability to be incorporated into polymers for modification of the system, but it also has very unique surfactant properties. The sodium, potassium, and ammonium salts of this C₂₁ dicarboxylic acid are unusually soluble in water, and the water solutions maintain relatively low viscosities even at high concentrations. The mono substituted derivatives of the C₂₁ dicarboxylic acid are prepared easily, and they provide unique properties for a variety of end uses. This paper illustrates the potential industrial applications for the dibasic acid and some of its derivatives in ink resins; adhesives; coatings; lubricants; plasticizers; corrosion inhibitors; synthetic coolants; emulsions; temporary coatings; floor polishes; and industrial, household, and institutional cleaners.     

Kinetics of reaction of C21 cycloaliphatic dicarboxylic acid and ethylenediamine

Kinetic studies were carried out on the reaction between ethylenediamine and C₂₁ cycloaliphatic dicarboxylic acid, prepared from dehydrated castor oil fatty acids and acrylic acid, in melt phase. The reaction was performed at six different temperatures ranging from 210 to 260°C and followed by determining the acid value of the product. The polyamidation reaction was found to follow an overall third order kinetics with an activation energy of 15.5 kcal/g mol.     

由桐酸甲酯合成C21二元酸单甲酯的研究与产物表征

以桐酸甲酯和丙烯酸为原料,通过Diels-Alder反应制备了标题化合物.正交试验表明最佳合成工艺为:桐酸甲酯和丙烯酸进料的质量比为1:0.247,以加入量为丙烯酸质量1%的对苯二酚作为阻聚剂,温度180℃反应3 h,加成产物相对于桐酸甲酯的产率为85%.经GC-MS分析,产物有6种同分异构体,纯度98.6%,并通过元素分析、红外光谱、1HNMR和13CNMR对产物进行了表征.     

酸性助水溶剂脱除木质素机理分析

系统探讨了酸性助水溶剂对甲苯磺酸(p-toluenesulfonic acid,TSA)和马来酸(maleic acid,MA)分离桉木各组分的工艺过程,并对其中木质素脱除机理进行了研究。通过分析对比两种优化后的工艺发现：(1)两种酸性助水溶剂都可以高效脱除木质素,TSA木质素脱除率为67.94%,MA为65.14%;(2)在相同质量分数下,TSA的木质素脱除率比MA更高;(3)在温和条件下,TSA木质素的β-芳醚键含量比MA的高,随着反应条件的加剧,TSA和MA处理后木质素产品中β-芳醚键含量逐渐减少;(4)两种酸性助水溶剂处理后,纤维素保留率都较高,可保持90%以上;但是半纤维素的降解程度随着反应条件的加剧而增加;(5)酸性助水溶剂质量分数越高,在疏水表面的接触角越小,对木质素的助溶作用越明显,脱除木质素效率越高,溶液中木质素聚集体的粒径越小。综上所述,酸性助水溶剂对木质素的脱除基于润湿溶解、木质素芳醚键断裂、半纤维素降解等的综合作用。相关研究可为后续实现温和条件脱木质素工艺优化及机理提供参考。     

Surface activity of mixtures of oxyethylated methyl dodecanoate and sodium dodecylbenzenesulfonate

Surface and interfacial tension and detergency of mixtures containing oxyethylated methyl dodecanoate and sodium dodecylbenzenesulfonate were determined. Synergism in the surface tension reduction was not observed. The competition for adsorption at the air/water interface between oxyethylated methyl dodecanoate and sodium dodecylbenzenesulfonate depended on the considered surface tension, the weight ratio of surfactants in the aqueous phase, and the hydrophile-lipophile balance of the nonionic surfactant. Generally, coverage of the interface with oxyethylated methyl dodecanoate increased when surface tension decreased. Nonionics were the dominant species at the interface in the important region of surface activity, i.e., for surface tensions below 40 mN m⁻¹. The mole fraction of the hydrophobic nonionic at the interface was higher than the contribution of hydrophilic oxyethylates. An increase of the surfactant ratio in the bulk phase affects the interfacial ratio of surfactants in the same way. The lowest interfacial tension (1.5 mN m⁻¹) at the hexadecane/water interface was observed for oxyethylated methyl dodecanoate having an average degree of oxyethylation equal to 8 and 10. Nearly 5 min was needed to achieve equilibrium value. Mixtures with sodium dodecylbenzenesulfonate decreased the interfacial tension somewhat less efficiently but the equilibrium was rapidly established. The standard washing powders containing oxyethylated methyl dodecanoates exhibited washing ability similar to that obtained for the powder with traditional alcohol oxyethylate.     

Separation and quantitative determination of monoacylglycerol mixtures by reversed phase HPLC

The separation and quantitative determination of underivatized saturated and unsaturated monoacylglycerol were examined by reversed phase high performance liquid chromatography using acetonitrile/water as the mobile phase. Monoacylglycerol (MG) mixtures containing saturated MG (C₆-MG-C₁₈-MG), monooleoylglycerol and monolinoleoylglycerol were sufficiently resolved, but mixtures of 1-MG and 2-MG with the same acyl group could not be separated under the conditions given below: column, C-8 chemical bonded column (4.6 × 250 mm); sample solvent, diethyl ether (UV detector at 210–215 nm) or chloroform; mobile phase, acetonitrile/water (7:3, v/v). Quantitative determinations were made for mixtures of three components (representative standard MGs) on a reversed phase column (Unisil Q, C-8) using a UV detector and the internal standard method. Standard deviation and coefficient of variation gave accurate, reproducible results.     

Melting points of binary fatty acid mixtures C6 to C12 and their application in the determination of purity

Summary The melting points of binary mixtures of adjacent even numbered carbon acids C₆ to C₁₂ have been presented in table form and graphically. It has been demonstrated that by the use of the molar melting point depression constants, the purity of these acids may be readily determined to an accuracy of one-fourth of one per cent when present in a concentration of 80% or more. The authors wish to thank Lever Brothers Company for permission to undertake and publish this work.     

Surface activity of mixtures of narrow-range distributed alcohol oxyethylates and sodium dodecylbenzenesulfonate

Surface and interfacial tension, emulsion inversion temperature, and detergency were determined for mixtures of sodium dodecylbenzenesulfonate and narrow-range distributed alcohol C₁₂−C₁₄ oxyethylates of different hydrophilicity. The mixtures of ionic and nonionic surfactants behave similarly to nonionic and ionic surfactants at the air/water and hydrocarbon/water interfaces, respectively. The air/water interface is mainly occupied by nonionic surfactant molecules. However, the interfacial tensions for mixtures of nonionic and ionic surfactants are similar to those of sodium dodecylbenzenesulfonate. Mixtures of narrow-range distributed oxyethylates and sodium dodecylbenzenesulfonate have a higher detergency at 40°C than individual components.     

Determination of aldehydes in mixtures of mono- and dicarboxylic acids

Determination of total aldehydes in fatty acid oxidation products was accomplished by using a colorimetric procedure based on 2,4-dinitrophenyl-hydrazine derivatives. To overcome problems of high reagent blanks and poor reproducibility the carbonyl derivatives were separated from excess reagent by extraction. Solubility and phase interface problems were avoided by using a sample dispersing solvent. Potential interferences were explored. The final procedure was demonstrated to be applicable from 25 μmoles to 2 mmoles/g carbonyl with a relative standard deviation of 3.5%.     

Simultaneous determination of dopamine and uric acid on nafion/sodium dodecylbenzenesulfonate composite film modified glassy carbon electrode

A novel electrochemical sensor has been constructed by using a glassy carbon electrode (GCE) coated with nafion/sodium dodecylbenzenesulfonate (SDBS). Differential pulse voltammetry (DPV) was used to study the electrochemical behaviors of dopamine (DA) and uric acid (UA). An optimum of 5 mM SDBS together with 0.05 wt% of nafion was used to improve the resolution and the determination sensitivity successfully. In 0.1 M phosphate buffer solution (pH 6.5), the modified electrode exhibited high electrocatalytical activity toward the oxidation of DA and UA with obvious reduction of overpotential. Compared with bare GCE, the modified electrode resolved the voltammetric response of DA and UA into two well-defined voltammetric peaks by DPV, which can be used for simultaneous determination of these species in mixture. The peak currents obtained from DPV were linearly related to the concentrations of DA and UA in the ranges of 4.0 × 10⁻⁷–8.0 × 10⁻⁵ M and 4.0 × 10⁻⁶–8.0 × 10⁻⁴ M, respectively. The detection limit of DA and UA (signal-to-noise ration was 3) were 5.0 × 10⁻⁸ and 4.0 × 10⁻⁷ M, respectively.     

The preparation of C19 dicarboxylic acid by the koch reaction

This paper describes the preparation of C₁₉ dicarboxylic acid by the Koch reaction with carbon monoxide and sulfuric acid of oleic, tall oil fatty, and partially hydrogenated tall oil fatty acids. The effects of changing reaction conditions upon the yield and purity of the product were examined. With the best conditions, it was possible to prepare light-colored, heat-stable C₁₉ dicarboxylic acid in 83% overall weight yield at 96% purity, containing 75% tertiary isomers and 25% secondary.     

C-21 dicarboxylic acids in soap and detergent applications

A unique polycarboxylic acid, 5(6)-carboxy-4-hexyl-2-cyclohexene-1-octanoic acid, has been available commercially for over 15 years. A new high-purity (>97%), light-color version of the C-21 dicarboxylic acid has been developed recently. Soaps of the C-21 dicarboxylic acid can be used as hydrotropes to increase the solubility of nonionic surfactants in aqueous solutions containing builders and/or anionic surfactants. Since these soaps are anionic fatty acid derivatives, they reduce the surface tensions of formulations, thus improving detergency. The nontoxic and biodegradable nature of this dicarboxylic acid makes it an attractive formulation component. This paper outlines application evaluations of the soaps prepared from the C-21 dicarboxylic acids. These evaluations demonstrate how the soaps interact with nonionic surfactants or pine oil to provide clear formulations, how they wet cotton skeins in neutral to highly alkaline solutions, and how they inhibit gel formation when preparing high-solids fatty acid soap solutions. Furthermore, the preparation and characterization of the soaps of the C-21 dicarboxylic acid products are discussed. Mass-balance equations describe the preparation of aqueous soap solutions at any given concentration. Characterization of the resulting soap solutions includes acid number, pH, color, color stability, foam stability, surface tension as a function of concentration, and hard-water compatibility.     

C16、C18混合脂肪酸分离技术研究进展

C16、C18混合脂肪酸中含有很多经济价值很高的组分,若能将这些组分分离出来加以利用,将极大地提高混合脂肪酸的利用价值,因此研究C16、C18混合脂肪酸的分离技术具有非常重要的意义。本文介绍了减压精馏、低温结晶、尿素包合、银离子络合、生物酶催化法等C16、C18混合脂肪酸分离方法在近十年来的研究进展,并分析了各种分离方法的优缺点和适用范围。减压精馏可以有效地将混合脂肪酸分离成C16组分与C18组分,但该法的主要问题是加热易使不饱和组分变质。尿素包合法最常用来分离C16、C18混合脂肪酸中的饱和组分与不饱和组分,目前对该法的研究主要集中在工艺条件的优化与改善。生物酶催化法选择性高、反应条件温和、绿色环保,目前已被用来分离α-亚麻酸以及γ-亚麻酸且效果良好。最后展望了C16、C18混合脂肪酸分离技术的发展前景,指出两种或多种分离方法组合以及生物酶催化法将是未来的发展趋势。     

Effect of hydrotropes on solubility and mass transfer coefficient of lauric acid

A comprehensive investigation on the solubility and mass transfer coefficient enhancement of lauric acid through hydrotropy has been undertaken. The solubility and mass transfer studies were carried out using hydrotropes such as sodium cumene sulfonate, sodium p-xylene sulfonate and sodium p-toluene sulfonate under a wide range of hydrotrope concentrations (0 to 3.0 mol/L) and different system temperatures (303 to 333 K). The effectiveness of hydrotropes was measured in terms of Setschnew constant K _s and reported for all hydrotropes used in this study. The solubility data are also fitted in a polynomial equation as the function of hydrotrope concentration.     

Aspen Plus流程模拟软件在C8芳烃分离工艺开发设计中的应用

C8芳烃由于原料来源不同,组分较多,组分间沸点差很小,使C8芳烃分离可供选择的流程较多,精馏分离所需理论板数多,采用传统的手工计算方法工作量大,使多方案的技术经济比较难于进行.本文运用精馏的基本原理,介绍了Aspen Plus在C8芳烃分离工艺开发设计中的应用,得出了以乙烯裂解汽油加氢抽提后的C8芳烃为原料,生产乙苯、邻二甲苯的最佳工艺流程和工艺条件.     

The determination of hydrotropes in detergent products by reverse-phase and ion-pair high performance liquid chromatography

The three aromatic sulfonates most commonly used as hydrotropes in detergent products can be qualitatively and quantitatively determined by high performance liquid chromatography (HPLC). Reverse-phase and paired-ion methods are described for separating sodium toluene, xylene and cumene sulfonates using conventional C18, C8, hexyl, and cyano columns as well as radially compressed HPLC cartridges. Ultraviolet (UV) detection at 254 nm gives more than adequate sensitivity for hydrotropes formulated between 0.5 and 15%. Sample preparation is simple and all components can be eluted within 15 min. The quantitation has been proven precise and accurate during routine analyses of either powdered or liquid detergent products.     

Separation of azeotropic mixtures of alcohols and water with FricDiff

FricDiff is an energy efficient separation process based on a difference in transport velocities of the components of a gas or vapor mixture when they diffuse through a sweep gas (‘enhancer’). The separation process takes place inside the pores of a non-selective macro-porous barrier. In this paper the separation of a 2-propanol–water mixture with the FricDiff-principle is studied, using CO₂ as the enhancer. A detailed numerical model is developed that describes the separation process that takes place inside a cylindrical FricDiff-unit. In this unit the vapor mixture to be separated and the sweep gas flow at opposite sides of a porous barrier in a counter current mode. Through the porous barrier selective mass transport of components of the feed mixture through the sweep gas takes place resulting in a separation. The model takes into account axial velocity profiles as a result of laminar flow of the gas and vapor mixtures through the flow channels, radial concentration gradients and radial velocities. The transport through the porous barrier is described with the Binary Friction Model. The influences of process conditions and the characteristics of the porous barrier on the separation process are studied.     

3-甲基吡啶和4-甲基吡啶的分离技术进展

3-甲基吡啶与4-甲基吡啶是生产高附加值精细化工产品的重要有机原料,广泛应用于医药、农药、染料、香料、饲料添加剂、食品添加剂、橡胶助剂及合成材料等领域。笔者综述了3-甲基吡啶与4-甲基吡啶混合体系的各种分离方法,并对其应用前景进行了展望。     

Separation of gaseous mixtures with asymmetric dense polymeric membranes

The advantages of using asymmetric polymeric membranes with a dense skin and a microporous backing for separation of permanent gas mixtures have been p     

Synthesis of dicarboxylic acid functionalized polysiloxane macromers

Summary Methods to synthesize aliphatic and aromatic dicarboxylic acid functionalized polydimethylsiloxane macromers were studied. Introduction of allyl group into dicarboxylic acid as a substituent, followed by hydrosilylation by silane terminated polydimethylsiloxane was found satisfactory to obtain the macromers.