Characterization of estolides produced from the acid-catalyzed condensation of oleic acid

Estolides produced from an acid-catalyzed condensation of oleic acid were characterized by high-performance liquid chromatography (HPLC), gas chromatography (GC), GC-mass spectrometry (MS) and nuclear magnetic resonance (NMR). C-8 reverse-phase HPLC provided a clean resolution of the estolide oligomers present in the reaction mixtures, allowing an average oligomier distribution to be calculated. Corroboration of HPLC results were obtained either through hydrolysis of the estolide mixture and quantitation of the hydroxy fatty acid content by GC, through the integration of the α-methylene protons adjacent to the carbonyl of the acids vs. the esterns in the¹H NMR spectrum, or by titration of the carboxylic acid with standardized base. GC and GC-MS analysis of the hydrolyzed estolide mixture indicated that the ester position were centered around the original double-bond position, with linkages ranging from positions 5–13. Likewise, the unsaturation was distributed along the fatty acid backbone.     

Acid-catalyzed condensation of oleic acid into estolides and polyestolides

Oleic acid, when treated with 1.0 equivalent of perchloric acid at 50°C, produced a 76% yield of polyestolide. The concentration of mineral acid greatly affected the rate of estolide formation, with increased rates under high acid concentrations. Over a range of temperatures from room temperature to 100°C, reaction rates increased at higher temperatures. However, high acid concentrations and temperatures produced undesirable side products, primarily lactones. Other acids catalyze the condensation of oleic acid to form estolide with the following relative rates: HClO₄ >H₂SO₄>p-toluenesulfonic>BF₃·Et₂O> montmorillonite K-10>HCl>H₃PO₄, HNO₃. Addition of water impedes the formation of estolide.     

Characterization of dihydroxystearic acid from palm oleic acid

Dihydroxystearic acid (DHSA) was prepared from palm oleic acid and characterized by chromatographic and spectroscopic methods (gas chromatography, thin-layer chromatography, Fourier transform infrared and nuclear magnetic resonance spectroscopy) as well as wet chemistry. The crude product has a melting point of 62°C, acid value of 179, saponification value of 178, and hydroxyl value of 196. The yield was about 90% based on unsaturation. The product obtained was found to contain DHSA, saturated fatty acids, and unknown products. DHSA is soluble in alcohol, and its solubility decreased by increasing the alcohol chain length. An irritancy test of DHSA indicated that purified DHSA is nonirritating.     

Mineral acid-catalyzed condensation of meadowfoam fatty acids into estolides

Meadowfoam fatty acids (83% monoenoic fatty acid), reacted with 0.01–0.1 mole equivalents of perchloric acid, gave 33–71% yield of estolide, an oligomeric 2° ester, resulting from self condensation. Equimolar amounts of perchloric acid to fatty acid failed to produce estolide but converted the fatty acids to a mixture of lactones, mainly γ-eicosanolactone. Temperature plays a critical role; higher temperatures (75–100°C), at the same acid concentration, provide lactones while lower temperatures (20–65°C) yield estolides. Lower acid levels (<0.1 mole equivalents) gave the best yields (≈70%) at 65°C. The estolide and monomer were characterized by nuclear magnetic resonance, infrared high-pressure liquid chromatography, gas chromatography, gas chromatography/mass spectrometry. The estolide is a mixture of oligomers with an average distribution near 1.65 ester units. The ester linkages are located mainly at the original double bond positions but have some positional isomerization to adjacent sites in accord with carbocation migration along the alkyl chain. The residual double bond of the estolide was extensively isomerized fromcis totrans and positionally along the chain. The distilled monomer is similar in structure to the unsaturated portion of the estolide with geometrical and positional double bond isomerization. In addition, a significant amount of cyclization of the fatty acids to lactone (≈30%) had occurred.     

Synthesis of estolide esters from cis-9-octadecenoic acid estolides

Oleic acid (cis-9-octadecenoic acid) was converted in excellent yield to the estolide, which was then esterified with 2,2-dimethypropan-1-ol (neopentyl alcohol), cis-9-octadence-1-ol (oleyl alcohol), and 2-propanol to generate the corresponding estolide esters. Higher-formula mass estolide esters were synthesized by reaction of the parent estolide with 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 1,5-pentanediol to give the corresponding diesters of oleic estolide, thus doubling the molecular size of the parent estolide. Pour points and viscosities were determined in order to evaluate these products for possible industrial application.     

Thermoplastic polyurethane elastomers from modified oleic acid

Two novel potentially biodegradable thermoplastic polyurethane elastomers with unique structure and morphology were prepared from modified oleic acid. The hardness and mechanical properties were controlled by adjusting the soft segment concentration (SSC). Epoxidized methyl oleate was converted to methyl‐9‐ or ?10‐hydroxystearate (hydroxystearate) by catalytic hydrogenation. The formed hydroxystearate was transesterified with 1,6‐hexanediol to obtain polyesterpolyol with molar mass 2500. Segmented polyurethanes with 50% and 70% SSC were prepared using the prepolymer method by reacting polyesterpolyol with diphenylmethane diisocyanate and 1,4‐butanediol as chain extender. Thermal and mechanical properties of the polymers indicated good micro‐phase separation. Both soft and hard segments displayed a certain degree of crystallization. Tensile strengths were 18 and 2.4 MPa for samples with 50% and 70% SSC, respectively. Elongations of 130% (50% SSC) and 43% (70% SSC) were somewhat lower than in comparable materials, presumably due to lower molar mass. © 2014 Society of Chemical Industry     

乙炔硫酸清净中硫酸单耗的影响因素

分析了100万t/a聚氯乙烯装置乙炔硫酸清净中硫酸单耗的影响因素,提出了解决措施,达到了节能降耗的目的。     

硫铁矿制酸装置生产优质液体SO_3联产发烟硫酸及精制硫酸

阐述用硫铁矿制酸装置生产液体SO_3联产w(H_2SO_4)115%的发烟硫酸及精制硫酸的产品方案设计、生产工艺过程以及在生产过程中遇到的问题及其解决办法。在硫铁矿制酸装置上成功生产3种产品,使产品售价平均达800元/t以上,大大提高了硫酸企业的市场竞争力。     

饱和油酸乙醇酰胺硫酸脂盐的合成

本文以油酸为原料经过适当的途径合成饱和油酸乙醇酰胺硫酸酯钠，并测定其表面活性性能。发现此化合物具有较好的钙皂分散性和很好的起泡性，可以用于各种洗涤剂的钙皂分散剂和发泡剂。     

板式浓硫酸冷却器的应用

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油酸催化氧化制壬二酸

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我国硫磺制酸现状

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硫酸阳极氧化故障处理

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硫酸净化工序斜板沉降器出来的污酸用自动反洗表面过滤器进行清污分离,介绍处理工艺流程及主要设备。每年可以回用硫酸1400t（折标酸）,年经济效益约为86．19万元。     

酸性镀锡液中游离硫酸的测定

本文提出了一种酸性镀锡液中游离硫酸含量的测量方法。阐述了该方法的原理,该方法准确度高,可满足生产的需要。     

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磷石膏是磷肥工业的排放废渣,文中提出了用氢气、一氧化碳或甲烷替代焦炭处理磷石膏的工艺构想,采用热力学软件对这4个过程的能耗进行了计算与分析,结果表明,新的磷石膏处理工艺过程能耗比传统的磷石膏制酸联产水泥工艺过程降低30%左右,且3个新工艺过程的能耗较为接近。通过对用甲烷部分氧化得到的还原性气体处理磷石膏新工艺与传统工艺的原料成本估算,发现前者的原料成本略低于后者,该新工艺构想前景广阔。     

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白云石是磷矿石中主要的有害杂质之一,其浮选行为对磷矿浮选结果有非常重要的影响.通过油酸作捕收剂时白云石的浮选行为和对油酸的吸附研究,揭示了白云石浮选的基本规律.     

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高纯度油酸是重要的精细化工产品。混合脂肪酸选择性加氢在化学工业中是一个非常重要的环节,同时也是生产高纯度油酸的合理途径。以雷尼镍作催化剂对混合脂肪酸进行选择性加氢正交试验和单因素水平试验,对所得产品进行凝固点测定和韦氏法碘值测定后得出最佳反应条件：在温度200℃、压力0．6MPa、时间1h、催化剂ω（B）=0．6％、搅拌250r／min的条件下可使混和脂肪酸碘值从120．84降到100左右,反应前后凝固点变化不大,提高了油酸的纯度。