Thermal oxidation of model molecules to reveal vegetable oil polymerization studied by NMR spectroscopy and self-diffusion

Oxidative polymerization of plant oils and lipids is poorly understood yet widely encountered. Oils and fats are renewable resources providing biofuels and polymers. Oil oxidation is accelerated at high temperatures, typically above 110°C, where triacylglycerides are converted into toxic compounds and viscous deleterious polymers. Polymerization of mono-unsaturated oil (210°C, 3 h, open to air) was investigated by comparing four similar sized molecules with different functional groups: oleic acid, methyl oleate, trans-7-tetradecene, and stearic acid. Non-volatile products identified by NMR spectroscopy are minor ketones for saturated fatty acid (stearic acid), epoxides for acyl chains without acid groups (methyl oleate, tetradecane) and copious oligomerization, through ester cross-links, for acyl chains with acid, and olefinic groups (oleic acid). Long range C H coupling clearly shows ester (not ether) cross-links, contradicting long-held beliefs. Chain fragmentation also occurs for heated oleic acid as revealed by formation of a species with a methylene group bonded to oxygen of an ester,  CH₂ O C(O) . Large size (slow diffusion) of the first oligomer (trimer) formed from oleic acid, used to represent hydrolyzed vegetable oil, was evidenced by DOSY (diffusion-ordered spectroscopy). Combined NMR results show oligomers found in heated oleic acid are fatty acid estolides. Model oil reactions demonstrate why olefin and carboxylic acid groups are required for polymerization.     

油酸和十二烷二酸的氨基酸酯的合成及其生物抗菌性

以L-丙氨酸乙酯盐酸盐、甘氨酸乙酯盐酸盐、L-蛋氨酸甲酯盐酸盐、L-亮氨酸乙酯盐酸盐和L-酪氨酸甲酯盐酸盐在1-乙基-(3-二甲基氨基丙基)碳酰二亚胺盐酸盐和1-羟基苯并三唑(HOBt)的作用下分别与油酸进行反应，生成了5种油酸的氨基酸衍生物；将L-丙氨酸乙酯盐酸盐和甘氨酸乙酯盐酸盐分别与十二烷二酸进行反应，生成了两种十二烷二酸的氨基酸衍生物，7种产物的收率均≥75%。利用FTIR、TGA、¹HNMR和LC-MS对产物进行了表征，测试了产物的水油分散性，考察了产物对金黄色葡萄球菌和大肠杆菌的抑菌性。结果表明，所合成的脂肪酰氨基酸酯均能在水油体系中分散，且具有较强的生物抗菌性，其中，0.01 mg油酸酰亮氨酸乙酯能有效地抑制金黄色葡萄球菌(菌数由2.0×10⁹ CFU/mL降至1.4×10⁷ CFU/mL)，而相同质量油酸酰酪氨酸甲酯则能抑制大肠杆菌(菌数由2.0×10⁹ CFU/mL降至1.8×10⁷ CFU/mL)。     

Thermal alteration of oleic acid in the presence of clay catalysts with co-catalysts

The effects of added co-catalysts on the clay catalyzed polymerization of oleic acid have been investigated. Heating oleic acid at 230 C for 3 hr with a clay catalyst gave a polymer fraction (dimer and trimer acids, 35% yield) and a monomer fraction (branched chain isomers of oleic acid, 27% yield) as the major products. The variation in yield between the polymer and monomer products was found to be dependent upon the co-catalyst used with the clay catalyst. For example, with both acidic and basic clays, polymer formation is favored (55% yield) in the presence of water and/or metal ions. In contrast, when Bronsted acids such as methanesulfonic or phosphoric acid are used as co-catalysts, the yield of branched monomer increased significantly (50%). Studies on the adsorption of oleic and Bronsted acids onto the clay surface showed that isomer formation is favored when both the oleic acid and the Bronsted acids are adsorbed onto the clay surface at selected molar ratios.     

A renewable approach to thermosetting resins

This is a review of recent developments of thermostable resins derived basically from vegetable oils. Natural vegetable oils have been transformed in polymers following three main routes. The first is the direct polymerization through the double bonds of the fatty acid chain. The cationic copolymerization of soybean oil with styrene, divinylbenzene and different amounts of styrenic monomers containing Si, B and P has been used to produce materials with improved flame retardant properties. The second route is the functionalization of the triglyceride double bonds to introduce readily polymerizable groups: The singlet oxygen photoperoxidation of the allylic positions of high oleic sunflower oil has been used to produce hydroperoxide-containing triglycerides that were dehydrated or reduced to produce respectively enone- and hydroxyl-containing triglycerides. The enone containing derivative has been chemically crosslinked with aromatic diamines through aza-Michael reactions leading to quinoline containing thermosets. The hydroxyl-containing triglycerides have been crosslinked radically prior the introduction of acrylate groups to produce conventional and flame retardant acrylate resins. The third route explored consists of using plant oil-derived chemicals like 10-undecenoic and oleic acids to produce tailor made monomers. Acyclic diene metathesis (ADMET) polymerization has been applied to prepare a set of thermosetting polyesters with flame retardant properties. Moreover thiol-ene “click” coupling has been used to prepare carboxylic monomers that have been explored to produce thermosetting polyanhydrides for fast drug delivery systems. A set of tailored polyols from the products of coordinative polymerization of the methyl epoxyoleate and the cationic ring opening polymerization of fatty acid-derived 2-oxazolines were also prepared. These polyols have been used to produce different thermosetting polyuretanes with a wide range of properties and characteristics.Finally, some recent research in producing benzoxazine thermosetting resins applying this renewable approach is presented. The benzoxazines based on diphenolic acid, a derivative of levulinic acid, are studied.     

Synthesis and Structural and Initial Cancer Cell Line Characterization of Organotin Polyesters from Dipicolinic Acid

The interfacial polymerization is employed to produce high polymer poly(ester ethers) from the reaction of the salt of dipicolinic acid and various organotin dihalides. They are rapidly synthesized with yield increasing as the length of the organotin alkyl chain increases. Infrared spectroscopy shows the formation of new bands derived from the Sn–O and Sn–O(CO) linkages. IR also shows that the products exist as a combination of molecular geometries about the tin atom. MALDI MS shows formation of ion fragment clusters to five and six units in length. The products show good inhibition of a variety of cancer cell lines including two pancreatic cancer cell lines.     

Conversion of Methyl Oleate to Branched-Chain Hydroxy Fatty Acid Derivatives

As part of a project to develop new and expanded uses of oilseed products and by-products (such as biodiesel, fuel additives, and lubricants), studies were conducted on the synthetic conversion of oleic acid (in the ester form) to branched-chain fatty acid ester derivatives. In these studies, methyl oleate was epoxidized and subsequently treated with four different organocuprate reagents in the presence of boron trifluoride diethyl etherate to produce novel branched-chain hydroxy acid derivatives. For each reaction, the two distinct isomeric products (methyl 9-alkyl-10-hydroxyoctadecanoate and methyl 9-hydroxy-10-alkyloctadecanoate) were isolated in the pure forms. Details of the synthesis and characterization (GC–MS, NMR, and differential scanning calorimetry) of these compounds will be discussed.     

Comparative Study of the Polymerization of Oleic Acid with Its Methyl Ester in an Azeotropic Saltbath

Oleic acid and its methyl ester were passed through an azeotropic salt bath consisting of 53% KNO₃, 40% NaNO₂ and 7% NaNO₃ at a varying rate at 320° C. Oleic acid was bodied better than its ester. But there is some decarboxylation in the bodied oleic acid. The oleic acid may be polymerized through the interaction of hydroxyl and oxirane as well as of carboxyl and oxirane groups with the formation of ether and ester respectively. The bodied methyl oleate also contains ester, ether and epoxide groups.     

温控钯-膦配合物催化油酸甲酯加氢反应的研究

制备了具有温控功能的膦配体脂肪醇聚氧乙烯醚氯化亚磷酸邻苯二酚酯(OPGPP),用FTIR、1HNMR对其结构进行了表征,将其与氯化钯的配合物用于催化油酸甲酯的加氢反应。考察了反应时间、反应温度、氢气压力、催化剂用量对反应的影响。在反应温度200℃,氢气压力7MPa,PdCl2用量为油酸甲酯质量的0.12%,n(PdCl2)∶n(OPGPP)=1∶10,反应时间4h的较佳反应条件下,加氢产物的羟值为114,碘值为25。对催化剂的重复使用性能进行了考察,该催化体系不经处理重复使用4次后,所得产物的羟值、碘值分别为102和27。     

油酸聚乙二醇酯对聚甲醛抗静电及力学性能的影响研究

研究了油酸聚乙二醇酯对聚甲醛电学性能及力学性能的影响,实验结果表明,油酸聚乙二醇酯能极大的降低聚甲醛的体积电阻,具有优异的抗静电效果。油酸聚乙二醇酯添加量为1份时,体积电阻率降为107Ω·cm数量级,最低体积电阻率可达106Ω·cm数量级。同时,油酸聚乙二醇酯的添加提高了聚甲醛的缺口冲击韧性,但聚甲醛的强度有所下降。     

Esterification reaction of oleic acid with a fusel oil fraction for production of lubricating oil

In this study, the esterification of oleic acid with a fraction of fusel oil was investigated. The variables that affect ester yield, such as temperature, molar ratio of oleic acid to alcohol, and amount of catalyst, were determined. Powdered silica gel was chosen to remove water instead of granular silica gel, magnesium sulfate, or benzene. The behavior of amyl alcohols and the fusel oil fraction was compared. The esterification reaction was carried out under the reaction conditions selected as optimal, and the ester conversion of the reaction was 97.3%. The product mixture compressed products, excess reactants, catalyst, and desiccant. Oleate ester and oleic acid (2.7%) were obtained using the refinement steps of filtration, evaportation, washing with distilled water, and drying over sodium sulfate.     

环氧油酸钙(锌)的合成及在PVC中的应用

以油酸、甲酸和双氧水为原料合成了环氧油酸,经复分解反应制得了环氧油酸钙(锌)盐,将其作为热稳定剂应用于PVC中,通过电导率、热老化以及热失重测试来考察环氧油酸钙(锌)的热稳定特性。研究结果表明:环氧油酸钙具有长期热稳定性,环氧油酸锌具有初期热稳定性,当环氧油酸锌/环氧油酸钙的比例为1∶3时,PVC的热稳定效果最好。     

Novel poly(ester amide)s from glycine and L‐lactic acid by an easy and cost‐effective synthesis

Novel low molecular weight poly(ester amide)s based on glycine and l ‐lactic acid with interest for the biomedical field were successfully prepared by interfacial polymerization, which is an easy and fast polymerization method. Preparation of the α‐amino acid based diamine, the l ‐lactic acid based diacyl chlorides and the poly(ester amide)s was carried out in the absence of catalysts. The structure of the different poly(ester amide)s was confirmed by ¹H NMR and Fourier transform infrared spectroscopies. The thermal behaviour of the synthesized poly(ester amide)s was evaluated by simultaneous thermal analysis, differential scanning calorimetry and dynamic mechanical thermal analysis. It was found that both the incorporation of an l ‐lactic acid oligomeric segment and the change in its central unit have an important influence on the thermal characteristics of the poly(ester amide)s. These novel poly(ester amide)s can be used as building blocks for the preparation of more complex structures. © 2013 Society of Chemical Industry     

Addition of glyoxylic acid ethyl ester to unsaturated fatty acid derivatives

The addition of glyoxylic acid ethyl ester to unsaturated fatty acid derivatives occurs with a maximum yield of 89%. The products are the corresponding 1:1-adducts. Temperature, reaction time, stoichiometry, and the concentration of the fatty acid derivative were investigated and optimized. A maximum yield was obtained with a fourfold excess of oleic acid ethyl ester, a reaction temperature of 200 °C, a reaction time of 24 h, and an oleic acid ethyl ester concentration of 1.3 mol/l.     

Synthesis and Structural Analysis of Branched-Chain Derivatives of Methyl Oleate

As part of a project to develop new value-added industrial applications for cottonseed oil (such as biodiesel, fuel additives, and lubricants), studies were conducted on the synthetic conversion of oleic acid to branched-chain fatty acid esters. In these studies, methyl oleate was brominated in the allylic position and subsequently treated with organocuprate reagents to produce novel branched-chain derivatives (methyl, n-butyl, phenyl). Original reaction conditions afforded only the branched methyl derivatives as major products. Modification of reaction conditions (lower temperature, less organocuprate reagent) afforded predominantly the desired n-butyl and phenyl derivatives and minimized products resulting from attack on the ester functionality. Details of the syntheses, characterization (especially by NMR), and the properties of the products (with emphasis on low-temperature properties) are discussed.     

Pressure Sensitive Adhesives Based on Oleic Acid

Existing pressure sensitive adhesives (PSA) are mostly based on petrochemical‐based polymers. This study reveals a new class of bio‐based polymers that can be used as PSA. The polymers are hydroxyl‐containing polyesters from the step‐growth polymerization of epoxidized oleic acid (EOA), an AB‐type monomer containing both a carboxylic acid group (A) and an epoxy group (B). The monomer is derived from epoxidation of renewable methyl oleate followed by selective hydrolysis of the ester group. The polymers (PEOA) of EOA were characterized for their chemical structure and molecular weight. The PEOA after being cured with a very small amount of a crosslinking agent could serve as a PSA with high peel strength, high tack force, superior shear resistance, excellent aging resistance, and excellent thermal stability. The PSA contains 99 wt% of green renewable materials. The PSA were also characterized for their viscoelastic properties and thermal properties.     

Quantification of Nonanal and Oleic Acid Formed During the Ozonolysis of Vegetable Oil Free Fatty Acids or Fatty Acid Methyl Esters

The ozonolysis of unsaturated lipids is a process that has been used to generate aldehydes, acids, alcohols, and other biobased chemical intermediates. Reported here is a method that can be used to measure the formation of nonanal and oleic acid during the ozonolysis of unsaturated vegetable oil fatty acids or their methyl esters to indicate the extent of the ozonolysis reaction. Derivatization was performed using boron trifluoride in methanol solution to transform nonanal and oleic acid into nonanal dimethyl acetal and oleic acid methyl ester, respectively. Undecanal and 10‐heptadecenoic acid were used as internal standards and separation was performed using gas chromatography coupled with a flame ionization detector. The method was validated by performing a standard addition procedure in which nonanal or oleic acid standards were spiked into samples collected during the ozonolysis of oleic acid or canola oil fatty acid methyl ester (FAME). Linear regression results indicated that the measured nonanal and oleic acid are in good agreement with the actual amounts of nonanal and oleic acid added to the sample with at least 98 % recovery. The application of the method was demonstrated by the successful measurement of nonanal and oleic acid formed throughout the ozonolysis process for high oleic canola oil FAME.     

Thermal behavior of methacrylic acid–ethyl acrylate copolymers

The thermal degradation behavior of copolymers of methacrylic acid (81.5–17.4 mol%) was studied using thermogravimetry (TGA) and differential scanning calorimetry (DSC) and the degradation products were analyzed using mass spectroscopy and DSC–FTIR. From mass spectroscopy, it was observed that in the copolymers the main degradation products obtained below 280°C included water, ethanol, and methanol, whereas at higher temperature (up to 400°C), CO₂, CO, and small olefins were liberated. Elimination of water and ethanol is attributed to anhydride formation, which is believed to result from two routes: (a) anhydride formation involving adjacent acid groups and (b) anhydride formation involving adjacent acid and ester groups. An endothermic transition in the DSC and percent weight loss in the TGA in the same temperature range (140–280°C) support the above proposal. An increase in weight loss with increase in EA content of the copolymer confirms the participation of EA in the anhydride formation. © 1994 John Wiley & Sons, Inc.     

油酸异丁酯的合成及其对生物柴油降凝效果研究

油酸与异丁醇在离子液体催化剂的作用下发生酯化反应制备油酸异丁酯。研究了催化剂用量、醇酸配比、反应时间、反应温度等对酯化反应转化率的影响,并通过测定凝固点、冷滤点、粘度来考察脂肪酸异丁酯对生物柴油的降凝效果。结果表明,当催化剂用量为2%,醇酸体积比2∶1(摩尔比6.8∶1),反应温度100℃,反应时间3 h,转化率达到95.6%。降凝实验结果表明,把一定量的脂肪酸异丁酯添加到生物柴油中可有效地降低生物柴油的凝固点、冷滤点,改善其低温流动性能。     

丙烯酸及酯聚合活性及阻聚措施的分析

烯烃类单体由于含有不饱和键,所以活性较高,容易发生自聚。本文分析了丙烯酸及酯的聚合活性,并对其阻聚进行了分析。结果表明,几种常用丙烯酸及酯产品的聚合活性如下:丙烯酸>丙烯酸甲酯>丙烯酸乙酯>丙烯酸丁酯>丙烯酸异辛酯;丙烯酸及酯常用阻聚剂的阻聚机理是富电子基团对缺电子丙烯酸及酯自由基的亲核反应。     

Synthesis and Characterization of Estolide Esters Containing Epoxy and Cyclic Carbonate Groups

The unsaturated sites in oleic 2‐ethylhexyl estolide esters (containing 35 % monoenic fatty acids) were converted into epoxide and five‐membered cyclic carbonate groups and the products characterized by Fourier transform infrared spectra (FTIR), ¹H, and ¹³C nuclear magnetic resonance (NMR) spectroscopies. Epoxidation of the alkene bonds was accomplished using performic acid generated in situ from formic acid and hydrogen peroxide. Greater than 90 % alkenes were converted into their corresponding epoxide groups as determined by oxirane values and the epoxide ring structure was confirmed by ¹H and ¹³C NMR. The estolide ester epoxide material was subsequently reacted with supercritical carbon dioxide in the presence of tetrabutylammonium bromide catalyst to produce the corresponding estolide ester containing the cyclic carbonate group. The signals at 1,807 cm^?1 and δ 82 ppm in the FTIR and ¹³C‐NMR spectra, respectively, confirmed the desired cyclic carbonate was produced. The carbonated estolide ester exhibited a dynamic viscosity, at 25 °C, of 172 mPa·s as compared to 155 mPa·s for the estolide ester starting material. The estolide ester structure of these new derivatives was shown to be consistent throughout their synthesis.