Phosphonates of Vegetable Oils—Characterization as Lubricants

Dialkyl phosphonates of vegetable oils were synthesized by reacting soybean (Soy) and high oleic sunflower (HOSuO) oils with dialkyl phosphites. Dimethyl, diethyl, and di-n-butyl phosphites were used in the synthesis and the resulting phosphonates were obtained in good yields and thoroughly characterized. All six phosphonates displayed poor solubility in polyalphaolefin-6; and four displayed adequate solubility (> 20% w/w) in HOSuO. Evaluation as anti-wear (AW) additives in HOSuO base oil blends showed the biobased phosphonates have similar coefficient of friction and similar or better wear scar diameter than zinc dialkyl dithio phosphates (ZDDP). It is concluded that vegetable oil phosphonates provide a promising biobased alternative to ZDDP and other commercial petroleum-based AW additives currently used in lubricant formulations.     

Direct Determination of Glycidyl Esters of Fatty Acids in Vegetable Oils by LC–MS

An LC–MS method using a single quadrupole mass spectrometer was developed for direct analysis of glycidyl esters of fatty acids in vegetable oils. Without any sample clean-up, this method provided acceptable recovery of seven glycidyl esters, comparable results to a previously-published method utilizing two solid-phase extraction steps, and consistent detection parameters after greater than 200 injections without any cleaning operations performed. This method could readily be implemented as a screening assay for glycidyl esters in most oil laboratories.     

Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC–TOFMS

Analysis of MCPD esters and glycidyl esters in vegetable oils using the indirect method proposed by the DGF gave inconsistent results when salting out conditions were varied. Subsequent investigation showed that the method was destroying and reforming MCPD during the analysis. An LC time of flight MS method was developed for direct analysis of both MCPD esters and glycidyl esters in vegetable oils. The results of the LC–TOFMS method were compared with the DGF method. The DGF method consistently gave results that were greater than the LC–TOFMS method. The levels of MCPD esters and glycidyl esters found in a variety of vegetable oils are reported. MCPD monoesters were not found in any oil samples. MCPD diesters were found only in samples containing palm oil, and were not present in all palm oil samples. Glycidyl esters were found in a wide variety of oils. Some processing conditions that influence the concentration of MCPD esters and glycidyl esters are discussed.     

Crystallization and Purification of 4,4′-Diaminodiphenyl Ether

The purification of 4,4′-diaminodiphenyl ether (ODA) was investigated. ODA, which contained impurities, was sublimated and anti-solvent (ethanol)-crystallized in N-dimethylformamide (DMF). Fourier transform infrared (FTIR) results revealed that the sublimated crystal was basically identical with the pure ODA sample. The influence of different amounts of ethanol on particle size distribution was analyzed during anti-solvent crystallization. The morphology of the ODA crystal was examined by scanning electron microscopy (SEM). The color of the sample enhanced from a brown powder to a colorless granular crystal. The purity of the sample could be increased from about 30 % to 87 %. With the operations of sublimation and anti-solvent crystallization, the purity, crystal morphology, and particle size distribution of ODA were significantly improved.     

Buckypapers of 4,4′-oxydianiline-modified polyvinylchloride and functional nano-filler obtained by resin infusion method

This study provides information on the fabrication and characterization of polyvinylchloride (PVC) buckypaper composite using resin infusion method. PVC modified with 4,4′-oxydianiline (ODA) was infiltrated through buckypapers made of purified multi-walled carbon nanotubes (P-MWCNTs) and functionalized MWCNTs (F-MWCNTs). The increases in P-MWCNT and F-MWCNT contents were investigated on the physical properties of BP-PVC-ODA/PEG (polyethylene glycol)/P-MWCNT and BP-PVC-ODA/PEG/F-MWCNT buckypaper composites. Fourier transform infrared spectroscopy was used for the functional group confirmation which proved the PVC modification and functionality of MWCNTs. The scanning electron micrographs of BP-PVC-ODA/PEG/F-MWCNT showed that intercalation of cross-linked polymer with nanotube produced a polymer-coated F-MWCNT mesh. The maximum degradation temperature (T _max) of functional composite BP-PVC-ODA/PEG/F-MWCNT 0.05 (484 °C) was higher than that of non-functional BP-PVC-ODA/PEG/P-MWCNT 0.05 (473 °C). The glass transition temperature (T _g) of BP-PVC-ODA/PEG/F-MWCNT 0.05 was 225 °C, while BP-PVC-ODA/PEG/F-MWCNT 0.03 yielded a lower T _g of 214 °C. Tensile strength of the functional buckypaper was also found to increase to 37.3 MPa with filler loading. According to X-ray diffraction, the amorphous character of buckypaper showed a trend towards crystal formation with filler loading. P-MWCNT-based buckypaper showed an electrical conductivity up to 4.12 × 10^?1 S/cm; lower than the electrical conductivity of functional buckypaper (1.98 S/cm). The results demonstrated that the resin infusion technique was a successful method to achieve high performance buckypapers compared with F-MWCNTs.     

Synthesis of 3,3′-dimethyl-4,4′-diaminodiphenylmethane catalyzed by zeolites replacing mineral acids

Synthesis of 3,3′-dimethyl-4,4′-diaminodiphenylmethane (MDT) from o-tolylamine and formaldehyde over zeolites was investigated. Among the three tested zeolites, Hβ showed higher catalytic activity than HY and HZSM-5 for MDT synthesis. In the case of Hβ as a catalyst, the effects of feed composition, reaction time and temperature on the yield and selectivity of product MDT were further examined to optimize process conditions. In an o-tolylamine:formaldehyde = 8:1 molar ratio, the two-step reaction running at 413 K for 0.5 h and then 433 K for 0.5 h gave the MDT yield of 87.5%.     

Effects of α-Tocopherol on Oxidative Stability and Phytosterol Oxidation During Heating in Some Regular and High-Oleic Vegetable Oils

The first part of this study evaluated oxidative stability in high-oleic rapeseed oil, palm olein, refined olive oil, low erucic acid rapeseed oil and sunflower oil. The results showed oxidative stability in the order: palm olein > high-oleic rapeseed oil > refined olive oil > low erucic acid rapeseed oil > sunflower oil, as determined by the Rancimat method. Addition of α-tocopherol at high levels of up to 0.2% increased the oxidative stability of refined olive oil, whereas the opposite effect was generally observed in the other oil samples. In the second part of the study, high-oleic rapeseed oil, palm olein, refined olive oil and refined olive oil containing 0.2% α-tocopherol were heated for 3, 6, 9 and 12 h at 180 °C. The peroxide and p-anisidine values generally increased over time in the samples, including olive oil containing 0.2% α-tocopherol. High-oleic rapeseed oil contained the highest amount of total sterols and total phytosterol oxidation products (POPs), but during heating the total POPs content increased moderately (~10%), in contrast to the threefold increase after 12 h of heating in palm olein and refined olive oil. Very high levels of 6-hydroxy derivatives of brassicastanol, campestanol and sitostanol and of 7-ketobrassicasterol were observed in high-oleic rapeseed oil samples. Addition of 0.2% α-tocopherol during heating significantly decreased POPs formation in refined olive oil (P < 0.05).     

Synthesis,characterization and crystal structure of one Mn(II) complex with 4,4′-bisimidazolylbiphenyl and 4,4′-sulfonyldibenzoic acid

One new title compound [Mn₃(BIBP)(sdb)(NO₂⁻)₂(H₂O)₂]_n·2DMF (1) (BIBP = 4,4′-bisimidazolylbiphenyl, sdb = 4,4′-sulfonyldibenzoic acid) has been synthesized under hydrothermal condition. The title compound was characterized by IR spectra, thermal analysis, single crystal and powder X-ray diffraction. Magnetic susceptibility measurements indicate that compound 1 exhibits antiferromagnetic coupling interaction.     

Synthesis of soluble polyarylenes containing alternating 4,4′-(1,1′-binaphthyl) and 4,4′-(3,3′-diphenyl)biphenyl structural units

Summary The synthesis and Ni(0) catalyzed homocoupling polymerization of 4,4-bis[5-(trifluoromethanesulfonyloxy)-2-biphenylyl]-1, 1-binaphthyl (9) are described. This polymerization reaction produces a soluble polyarylene containing alternating 4,4-(1,1-binaphthyl) and 4,4-(3,3-diphenyl)biphenyl structural units.     

Production of Tocopherol Concentrates by Supercritical Fluid Extraction and Chromatography∗

Abstract

Supercritical fluid extraction (SFE) has been combined with supercritical fluid chromatography (SFC) in a preparative mode to develop a system for fractionating and enriching high value constituents contained in seed oil matrices. The system consists of an extraction step sequenced on-line with a sorbent filled column, which permits a SFE-enriched tocopherol fraction to be diverted onto the chromatographic column for further enrichment of the tocopherols. For the SFE stage, the tocopherol enrichment was optimized at 25 MPa and 80°C for soybean flakes and rice bran. However, total tocopherol recovery and enrichment was also found to be a critical function of the mass ratio of CO₂/seed charge. Approximately 60% of the available tocopherols in soyflakes can be recovered in the SFE step, yielding enrichment factors of 1. 83–4.33 for the four tocopherol species found in soybean oil. Additional enrichment of tocopherol species can be realized in the SFC stage, ranging from 30.8 for delta-tocopherol to 2.41 for beta-tocopherol.

     

Rapid Preparation Process of Silver Nanoparticles by Bioreduction and Their Characterizations

Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag（NH3）2]^＋ to Ago in the solution into which some amount of OH^- was introduced. The surface plasmon resonance centered at 425 nm on the UV-vis spectra and five broad Bragg reflections on the XRD pattern showed that stable silver nanoparticles were formed during the bioreduction process. TEM and SEM observations suggested that the silver nanoparticles were uniform in size and well dispersed on the cells and in the solution. Therefore, silver nanoparticles could be prepared rapidly by this bioreduction technology.     

Two-dimensional assembling of 4,4′-bipyridine and 4,4′-azopyridine bridged iron (II) linear coordination polymers via hydrogen bond

Novel two-dimensional polymers, [Fe(L¹)(H₂O)₂(NCX)₂] · L¹ (L¹ = 4,4′-bipyridine (bipy)) (1, 2) and [Fe(L²)(CH₃OH)₂-(NCX)₂] · L² (L² = 4,4′-azopyridine (azpy)) (3) and X = S (1,3),Se (2), have been synthesized and characterized by X-ray crystallography. The structures reveal the formation of trans-L-bridged [Fe(NCX)₂(Y)₂] where Y = H₂O, CH₃OH linear chains assembled into two-dimensional networks by hydrogen bonds between the uncoordinated ligand L and the coordinated solvent molecules.     

Pervaporation of water/acetic acid through polyimide membranes from 3,3′, 4,4′-benzophenone tetracarboxylic dianhydride and 4,4′-oxydianiline

Summary Pervaporation performance of polyimide (PI) membrane from 3,3, 4,4-benzophenone tetracarboxylic dianhydride (BTDA) and 4,4-oxydianiline (ODA) was investigated at 80wt% feed acetic acid concentration and at 65°C. Imide contents in PI film were estimated by thermogravimetric analysis (TGA) method. The separation factor of PI membrane increases with the degree of imidization, while the flux was almost constant. The separation factor toward water through PI-94 membrane was about 417 with the flux of 47 g/m². hr measured at 65°C and with 80wt% acetic acid as a feed. PI-94 showed the best pervaporation performance toward the separation of water from acetic acid solution among the PI membranes investigated. The swelling behaviors at various feed concenration were also examined.     

Separation of Quercentin by Pre-dispersed Solvent Extraction

Pre-dispersed solvent extraction (PDSE) was used to extract quercentin from its diluted solution. The influences of temperature, phase volume ratio (PVR), concentration of sodium Dodecyl benzene sulphonate and pH value etc. on the extraction efficiency were examined. It is found that, compared with traditional extraction techniques under the same condition, a higher extraction productivity can be obtained by PDSE. The stability of colloidal liquid aphrons plays an important role in this process. In a certain scope, the extraction efficiency increases with PVR. Excessive amount of solvent is not much helpful. A new analytical method by using ultraviolet spectrometer to determine the concentration of quercentin is established.     

Aqueous polymerization of acrylamide initiated by 4,4′-azobis (4-cyano pentanol) and chain extension of polyacrylamide by means of ceric ion redox systems

Summary The polymerization of acrylamide (AA) initiated by 4,4-azobis (4 cyanopentanol) (ACP) was investigated in aqueous solution at 60°C. The molecular weight and the conversion depend on polymerization duration and initiator concentration. Polymerization of AA initiated by ACP yields polyacrylamide (PAA) with hydroxyl terminal groups. Redox polymerization of AA initiated by hydroxyl terminated PAA in conjuction with Ce(IV) provided increase in the molecular weight of the initial polymer.     

The electrochemical properties of polyaniline derivatives: poly(4,4′-diphenylamine methylenes) and poly(4,4′-diphenylimine methines)

Summary The electrochemical properties of poly(4,4-diphenylamine methylenes) and poly(4,4-diphenylimine methines) were investigated by cyclic voltammetry. A dehydrogenation reaction occured when poly(4,4-diphenylamine methylenes) underwent a electrochemical reaction and transformed to poly(4,4-diphenylimine methines). The fully oxidized poly(4,4-diphenylimine methines) had the electrochemical band gaps of 1.60–1.72 eV, which were found to significantly smaller than those of the fully reduced poly(4,4-diphenylamine methylenes).     

Syntheses and properties of aromatic polyamides derived from 4,4′-oxydibenzoic acid and aromatic diamines

A series of aromatic polyamides were synthesized by direct polycondensation of 4,4-oxydibenzoic acid with various aromatic diamines inN-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride, using triphenyl phosphite and pyridine as condensing agents. The resultant polyamides had inherent viscosities of 0.21-1.48 dL/g. Most of the polymers were organo-soluble and could be solution-cast into flexible and strong films. The glass transition temperatures (T_gs) of most polyamides could be determined with the help of differential scanning calorimetry (DSC) traces, which were recorded in the range of 170–275 °C. Thermogravi metric data of these polymers indicated that most of the polyamides showed no significant weight loss before 450 °C in either air or nitrogen atmospheres.     

Kinetics of Reaction of Castor Oil Trimethylol Propane Polyol and 4,4′ Diphenyl Methane Diisocyanate

The kinetics of the uncatalyzed reaction of diphenyl methane diisocyanate and castor oil (CO)/trimethylol propane (TMP) polyol, with xylene as solvent at different temperatures, solvent concentration and NCO/OH ratios were investigated. The polyol was synthesized from castor oil and trimethylol propane (2-ethyl-2-(hydroxymethyl)-1,3-propanediol) with equivalent ratio of 1:3 via transesterification mechanism. Polyol was then characterized using FTIR spectroscopy and liquid chromatography mass spectroscopy (LCMS) under atmospheric pressure chemical ionization mode. All the reactions obeyed second order kinetics. Enthalpy changes, activation energies and entropies of activation were also calculated. Kinetic data from these reactions will facilitate modeling of these reactions in a batch reactor.     

Studies on Cure Kinetics of Diglycidyl Ether of 4,4′-Bisphenol/4,4′-Diaminobiphenyl Using the Advanced Isoconversional Method

The cure kinetics of a rigid-rod epoxy monomer, diglycidyl ether of 4,4′-bisphenol (DGEBP), and the curing agent with the similar rigid-rod group, 4,4′-diaminebiphenyl (DABP), was studied using an advanced isoconversional method (AICM). DGEBP/DABP curing system was carried out by means of differential scanning calorimetry (DSC). Three exothermic peaks were depicted by nonisothermal DSC studies: the first two peaks were attributed to the curing reaction, and the last peak was attributed to the decomposition of the cured epoxy resin. The LC phase transformation of the curing process was observed by PLM. Using AICM, the largest activation energy of the curing reaction of DGEBP/DABP system was obtained as 108 kJ/mol. It can also be learned that LC phase transformation of the curing process affects the reaction significantly.     

Preparation and thermotropic properties of copoly(4,4′-biphenylene sebacate-co-eicosanedioate)s

Summary A series of thermotropic copoly(4,4-biphenylene sebacate-co-eicosanedioate)s were prepared by melt polycondensation of 4,4-biphenylene diacetate, sebacic acid and eicosanedioic acid. Their thermal transitions and liquid crystalline properties were investigated by DSC and polarized micrrocope. The copolyesters were found to exhibit a smectic phase, but no nematic phase was observed upon cooling. The smectic-isotropic transition temperature decreased as the content of eicosanedioate unit increased, and the corresponding transition heat did not change to a great extent. However, the crystalline-smectic transition temperature showed an eutectic behavior, and the crystalline-smectic transition heat was depressed considerably after copolymerization. The X-ray diffraction data of the copolyesters after thermal treatment were measured and compared with the thermal properties measured by DSC.