Combined zirconia toughened alumina (ZTA) stacks obtained by electron beam physical vapour deposition

Ion assisted electron beam physical vapour deposition (EB-PVD) technique was used for three zirconia toughened alumina (ZTA) batches containing 15, 25, 35, mole% ZrO₂ and c-zirconia ceramic multilayer deposition on 617-Ni based alloy substrate. The ceramic batches were prepared via sol-gel technique. The thickness of the coated layers was found to be 0.66 μm for ZTA layers and 0.65 μm for c-zirconia layer. Evaluation of the microstructure of the samples coated with c-zirconia on the top of different ZTA coats reveals three different regions. First region indicates c-ZrO₂ coat, second region exhibits ZTA layers, while third is the metallic substrate. The top coat microstructure can be divided into two zones. The inner zone (ZTA zone), which is the early part of multiple nucleation and subsequent growth of the columnar microstructure. The outer zone (c-ZrO₂) which is crystallographically perfect columnar YSZ coatings produced by EB-PVD.     

Separation of natural polyunsaturated fatty acids by means of lodolactonization

Conditions of the iodolactonization reaction (ILreaction) were optimized as a method for separation of natural polyunsaturated fatty acids. The effects of the solvent, temperature and the ratio of components of the iodizing complex KI/I₂ upon the rate of the synthesis of several iodolactones (ILs) in the IL-reaction are described. It was shown that the rate of formation of γ-ILs was significantly higher than that for δ-ILs. This offers opportunity for obtaining pure docosahexaenoic acid (DHA) from fatty acid (FA) concentrates. The possibility for selective reduction of δ-ILs in the presence of γ-ILs to yield pure arachidonic acid (AA) or eicosapentaenoic acid (EPA) or fatty acid concentrates has been demonstrated. Preparation of pure AA from a mixture of AA, DHA and other FAs by the IL-reaction without Chromatographie procedures is described.     

Dietary fatty acids influence the growth and fatty acid composition of the yellow mealworm <Emphasis Type="Italic">Tenebrio molitor</Emphasis> (Coleoptera: Tenebrionidae)

Fat is the second most abundant component of the nutrient composition of the mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) that represents also an interesting source of PUFA, especially n-6 and n-3 fatty acids, involved in prevention of cardiovascular diseases. This study investigated the possibility of modifying the fat content and the FA composition of yellow mealworms through feeding and how this would be influenced by developmental stages, pupal sex, and generation with the future aim of applying this coleopteran as a diet supplement for human health. Growth rate and cumulative mortality percentage on the different feeding substrates were also evaluated to select the optimal conditions for a mass-raising of this insect species. Despite the different fat content in the six different breeding substrates used, T. molitor larvae and pupae contained a constant fat percentage (>34% in larvae and >30% in pupae). A similar total fat content was found comparing larvae and male and female pupae of the second generation to those of the first generation. On the contrary, FA composition differed both in larvae and pupae reared on the different feeding substrates. However, the exemplars reared on the diets based on 100% bread and 100% oat flour showed SFA, PUFA percentages, and an n-6/n-3 ratio more suitable for human consumption; the diet based on beer yeast, wheat flour, and oat flour resulted in a contemporary diet that most satisfied the balance between a fat composition of high quality and favorable growth conditions.     

Oxidative decarboxylation of unsaturated fatty acids

Long‐chain internal olefins were prepared by silver(II)‐catalyzed oxidative decarboxylation of unsaturated fatty acids by sodium peroxydisulfate. Similar to saturated carboxylic acids, 1‐alkenes were the major decarboxylation product in the additional presence of copper(II), whereas in the absence of copper(II) alkanes were predominantly formed. In both cases, the internal unsaturation of the fatty acids remained largely intact, although the moderate yields indicated that side reactions occurred to a significant extent. The simple procedure makes this multistep one‐pot reaction useful for the synthesis of a variety of internally unsaturated hydrocarbons. The purified products, almost all of which are prepared for the first time, may serve as reference compounds for studies on the heterogeneously catalyzed decarboxylation of triglycerides and fatty acids in the absence of hydrogen. Practical applications: The products of the chemistry described in this contribution, i.e., unsaturated long‐chain hydrocarbons, provide bio‐based building blocks for further chemical modification toward products which may be applied as (bio)fuels, lubricants, solvents, and polymeric materials.     

Regiospecific distribution of fatty acids in triacylglycerols and phospholipids from broad beans (Vicia faba)

Regiospecific distributions of fatty acids of triacylglycerols (TAG) and phospholipids (PL) separated from broad beans (Vicia faba) of four cultivars (Minpo, Sanuki, Nintoku and Sanren) were investigated. The major lipid components were PL (47.5–50.5 wt‐%) and TAG (47.7–50.1 wt‐%), while steryl esters, hydrocarbons, free fatty acids, diacylglycerols and monoacylglycerols were present in minor proportions (1.6–2.4 wt‐%). The PL components isolated from the four cultivars were phosphatidylcholine (56.4–58.4 wt‐%), phosphatidylethanolamine (20.3–21.7 wt‐%) and phosphatidylinositol (16.6–18.6 wt‐%). Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among these PL. The principal characteristics of the fatty acid distribution in the TAG and PL were evident in the beans: Unsaturated fatty acids were predominantly concentrated in the sn‐2 position while saturated fatty acids primarily occupied the sn‐1 or sn‐3 position in these lipids. The lipid components and fatty acid distributions were almost the same in the four cultivars and were not influenced by genetic variability and planting location. These results could be useful information to both consumers and producers for the manufacture of traditional broad bean foods in Japan.     

Positional distribution of fatty acids in triacylglycerols and phospholipids from adzuki beans (Vigna angularis)

The fatty acid distributions of triacylglycerols (TAG) and major phospholipids (PL) obtained from adzuki beans (Vigna angularis) were investigated. The total lipids extracted from the beans were separated by thin‐layer chromatography (TLC) into eight fractions. The major lipid components were PL (63.5 wt‐%), TAG (21.2 wt‐%), steryl esters (7.5 wt‐%) and hydrocarbons (5.1 wt‐%), while free fatty acids, diacylglycerols (1,3‐DAG and 1,2‐DAG) and monoacylglycerols were also present in minor proportions (0.2–1.1 wt‐%). The major PL components isolated from the beans were phosphatidylcholine (45.3 wt‐%), phosphatidylethanolamine (25.8 wt‐%) and phosphatidylinositol (21.5 wt‐%). Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among the three PL. With a few exceptions, however, the principal characteristics of the fatty acid distribution in the TAG and three PL were evident in the beans: Unsaturated fatty acids were predominantly concentrated in the sn‐2 position while saturated fatty acids primary occupied the sn‐1 or sn‐3 position in the oils of the adzuki beans. In general, these results could be useful to both consumers and producers for the manufacture of traditional adzuki foods in Japan.     

Extraction and separation of molybdenum(VI) from acidic media by fatty hydrazides

BACKGROUND: The increasing demand for molybdenum has encouraged the development of low‐cost and environmentally friendly extractants to recycle and recover this metal. In the present study, solvent extraction of Mo(VI) from acidic media using a mixture of fatty hydrazides synthesised from palm olein as the extractant was carried out. The effects of various parameters such as acid, diluent, contact time, extractant concentration, metal ion concentration and stripping agent and the separation of Mo(VI) from other metal ions such as Co(II), Ni(II), Al(III) and Mn(II) were investigated. RESULTS: It was found that the extraction of Mo(VI) into the organic phase involved the formation of 1:3 complexes. Mo(VI) was successfully separated from commonly associated metal ions such as Ni(II), Co(II), Al(III) and Mn(II). Mo(VI) stripping from the loaded organic phase was studied using different acidic and alkaline solutions and was found to be optimal with ammonium hydroxide solution. CONCLUSION: These results are useful for the development of a method to recover Mo(VI) from acidic media utilising fatty hydrazides as the extractant. Copyright © 2008 Society of Chemical Industry     

An integrated process of catalytic hydrolysis and membrane separation for fatty acids production from lard oil

An integrated process of catalytic hydrolysis and membrane separation was developed for fatty acids (FAs) production from lard oil. Both sulphonated cation exchange resin (SCER) and 0.98 g/g H₂SO₄ as catalysts were used to produce fatty acids (FAs) from lard oil by three‐step hydrolysis, respectively. Simultaneously, polyethersulphone (PES) ultrafiltration membrane was employed to separate glycerol and water from the products. The hydrophilicity and morphology of the pristine and used PES membranes were characterized by contact angle measurement and field‐emission scanning electronic microscopy, respectively. The final optimal yields of FAs obtained by SCER and H₂SO₄ catalysis at 100 °C and atmospheric pressure were 85.6 % at 16.0 h of operation and 94.5 % at 18.0 h of operation, respectively. Furthermore, the yield of FAs obtained from an integrated process of SCER‐catalyzed hydrolysis and membrane separation achieved up to 99.9 % at 10.0 h, 90 °C, and operating pressure of 100 kPa.

     

Determination of fatty acids and some undesirable fatty acid isomers in selected Turkish margarines

The fatty acid composition and total trans fatty acid content in 10 margarines produced in Turkey were determined by capillary gas chromatography and Fourier transform‐infrared spectroscopy (FT‐IR) spectroscopy. The fatty acid composition ranged as follows: saturated fatty acids, C16:0 (palmitic) 11.3 to 31.8% and C18:0 (stearic) 5.7 to 8.7%, monounsaturated fatty acids, C18:1 (oleic) 21.8 to 35.7% and C18:1 trans isomers 0.4 to 27.4%, polyunsaturated fatty acid, C18:2 linoleic acid 5.2 to 40.2%. Some positional isomers of C18:1 as cis‐11‐octadecenoic acid varied from 0.7 to 4.6% and cis‐13 trace to 2.4%. The total trans fatty acid contents were between 0.9 and 32.0% when measured with capillary gas chromatography and between 0 and 30.2% with FT‐IR spectroscopy. Some of the margarines analyzed contained trace amount of trans fatty acids which could not be detected by FT‐IR spectroscopy.     

Structured lipids from high-laurate canola oil and long-chain omega-3 fatty acids

The lipase-assisted acidolysis of high-laurate canola oil (HLCO; Laurical 25) with long-chain n−3 FA (DHA and EPA) was studied. Response surface methodology was used to obtain a maximal incorporation of DHA or EPA into HLCO. The studied process variables were the amount of enzyme (2–6%), reaction temperature (35–55°C), and incubation time (12–36 h). The amount of water added and the mole ratio of substrates (oil to DHA or EPA) were kept at 2% and 1∶3, respectively. All experiments were conducted according to a face-centered cube design. Under optimal conditions (4.79% of enzyme; 46.1°C; 30.1 h), the incorporation of DHA into HLCO was 37.3%. The corresponding maximal incorporation of EPA (61.6%) into Laurical 25 was obtained using 4.6% enzyme, a reaction temperature of 39.9°C, and a reaction period of 26.2 h. Examination of the positional distribution of FA on the glycerol backbone of modified HLCO with DHA showed that the DHA was primarily located in the sn-1,3 positions of the TAG molecules. However, lauric acid also remained mainly in the sn-1,3 positions of the modified oil. For EPA-modified Laurical 25, lauric acid was present mainly in the sn-1,3 positions, whereas EPA was randomly distributed over the three positions.     

Determination of essential fatty acids in captured and farmed tambaqui (Colossoma macropomum) from the Brazilian Amazonian area

This research aimed to quantify the methyl esters of linoleic (LA), γ-linolenic (LNA), arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids in the muscular tissue and orbital cavity of farmed tambaqui (Colossoma macropomum) and in those caught in the Brazilian Amazonian Area during two periods. For the farmed fish, the amounts of LA, LNA, AA, EPA, and DHA found in the muscle were 208.0, 12.4, 57.9, 5.0, and 25.1 mg/g, respectively. The amounts of these FA in the orbital cavity were 103.4, 6.6, 20.0, 4.4, and 8.1 mg/g for LA, LNA, AA, EPA, and DHA, respectively. For the fish caught during the flood period, the LA, LNA, AA, EPA, and DHA levels were 297.3, 50.7, 32.3, 3.8, and 14.1 mg/g in the muscle and in the orbital cavity were 259.7, 40.3, 10.8, 5.5, and 9.3 mg/g, respectively. For the fish captured in the dry season the levels of LA, LNA, AA, EPA and DHA in the muscle were 262.0, 48.0, 157.6, 9.3, and 40.2 mg/g and in the orbital cavity were 102.5, 15.7, 24.6, 7.0, and 8.9 mg/g. According to their contents of AA, EPA, and DHA, tambaqui captured in the dry season can be considered as a rich source of EFA. The adipose tissue of the orbital cavity did not show sufficiently high EPA and DHA contents to classify it as a better source of FA than the muscle.     

Separation of VOCs from N2 using poly(ether block amide) membranes

This work deals with the separation of volatile organic compounds (VOCs) from nitrogen streams for organic vapour emission control by poly(ether block amide) membranes. As representative air pollutant VOCs, n‐pentane, n‐hexane, cyclohexane, n‐heptane, methanol, ethanol, n‐propanol, n‐butanol, acetone, dimethyl carbonate, and methyl tert‐butyl ether were used in this study. The separation of both binary VOC/N₂ and multicomponent VOCs/N₂ gas mixtures was carried out, and the membranes exhibited good separation performance. A VOC concentration of more than 90 mol% was achieved at a feed VOC concentration of 5 mol%. It was found that the permeances of the VOCs were mainly dominated by their solubilities in the membrane, whereas the permeance of N₂ was affected by the presence of the VOCs. The permeance of N₂ in the VOC/N₂ mixtures was shown to be higher than pure N₂ permeance due to membrane swelling induced by the VOCs dissolved in the membrane. Nevertheless, theVOC/N₂ selectivity increased with an increase in the feed VOC concentration. Among the VOCs studied, the membrane showed a higher permeance to alcohol VOCs than paraffin VOCs. The effects of feed VOC concentration, temperature, stage cut, and permeate pressure on the separation performance were investigated.     

Kinetics of electroless copper deposition using cobalt(II)-ethylenediamine complex compounds as reducing agents

Electroless copper deposition using Co(II)-ethylenediamine (En) complexes as reducing agents was investigated in 0.4–1.2 M En solutions at 50 and 70 °C. There is a complicated dependence of the process rate on pH, En concentration and temperature. A copper deposition rate up to 6 m h^–1 (50–70 °C) in relatively stable solutions (pH 6) can be achieved. The stoichiometry of the Cu(II) reduction at pH 6–7 corresponds to the reaction:

Separation of rhodium(III) and iridium(IV) chlorido complexes using polymer microspheres functionalized with quaternary diammonium groups

Merrifield resin functionalized with different quaternary diammonium groups derived from ethylenediamine (EDA), tetramethylenediamine (TMDA), hexamethylenediamine (HMDA), 1,8-diaminooctane (OMDA), 1,10-diaminodecane (DMDA) and 1,12-diaminododecane (DDMDA) were investigated for the separation of [RhCl₅(H₂O)]^2? and [IrCl₆]^2?. Selective loading of [IrCl₆]^2? in 6 M HCl medium onto the column was achieved in the presence of [RhCl₅(H₂O)]^2? by the synthesized sorbents. The iridium loading capacities were 3.80, 6.49, 13.07, 19.29, 27.09 and 4.36 mg/g for EDA, TMDA, HMDA, OMDA, DMDA and DDMDA-functionalized microspheres, respectively. The materials showed great potential for application in separating rhodium and iridium from aqueous HCl solutions.     

Solvent Extraction and Separation of Gallium(III) using Hexaacetato Calix(6)Arene

Gallium(III) was extracted at pH 3.5 by equilibrating eight min with 10 mL of 0.0001 M acetyl derivative of calix(6)arene in xylene. Gallium(III) was stripped quantitatively with 0.1 N hydrochloric acid and determined spectrophotometrically with 0.01% PAR at 510 nm. The nature of the extracted species was determined from the log-log plots and its stoichiometry was confirmed by numerical treatment to experimental data. The IR analysis of Ga(III) loaded organic phase was also studied. The conformational change of reagent during complex formation was studied from the ¹H NMR treatment. The temperature dependence of the extraction equilibrium and metal loading capacity of the reagent was also evaluated. The proposed method was successfully applied for the extraction and separation of multicomponent mixtures, synthetic mixtures, and binary and ternary separation of gallium from the associated elements. The results obtained were reproducible and accurate.     

Liver lipids and fatty acids of the sting ray Dasyatis bleekeri (Blyth)

The sting ray, Dasyatis bleekeri (Blyth), has been studied for lipids and fatty acids of its liver. The neutral lipids identified were hydrocarbons, wax esters, steryl esters, 1-O-alkyl-2,3-diacylglycerols, triacylglycerols, and sterols. Neutral lipids were predominant (91.8%), major components being triacylglycerols (92.7%). Polyenoic fatty acids of n-3 series, viz. eicosapentaenoic acid and docosahexaenoic acid, were high in the phospholipid and neutral lipid fractions. Cholesterol was the major component (67.9%) in the steryl ester fraction. Glyceryl ethers, with chainlengths up to 30 carbons, were recorded with unsaturated, anteiso, iso, and normal chains. In wax ester alcohols, up to 32-carbon chains were recorded. Hydrocarbons were up to 36-carbon chains with anteiso, iso, and normal chains. Among branched chain hydrocarbons, pristane was the major component (6.7%) and squalene was present at the level of 3.5%. Chimyl and batyl alcohol backbones were the major components found in 1-O-alkyl-diacylglycerols.