含硼杂环抗磨添加剂的合成及其摩擦学性能

 从分子设计的观点出发，合成了一种新型含硼杂环抗磨添加剂SONB，采用四球摩擦磨损试验机评价了其摩擦学性能。结果表明，在菜籽油(RSO)中加入添加剂SONB后，承载能力有较大提高，磨斑直径明显减小，摩擦系数明显降低。从磨损表面SEM/EDS、XPS分析结果可以推断，该添加剂在摩擦过程中发生了化学分解反应，S元素在钢球的表面形成了一层含Fe₂(SO₄)₃和FeS₂ 的反应膜，N、B元素则以吸附膜的形式存在于摩擦表面， 两种膜的协同作用提高了菜籽油的减摩抗磨性能及承载能力。     

Effect of different fermentation parameters on bioethanol production from corn meal hydrolyzates by free and immobilized cells of Saccharomyces cerevisiae var. ellipsoideus

BACKGROUND: Bioethanol produced from renewable biomass, such as corn meal, is a biofuel that is both renewable and environmentally friendly. Significant scientific and technological investments will be needed to achieve substitution of conventional fossil fuels with alternative fuels. The ethanol fermentation of enzymatically obtained corn meal hydrolyzates by free and immobilized cells of Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. The initial glucose and inoculum concentration and the time required for the efficient ethanol production were optimized taking into account parameters such as ethanol concentration, ethanol yield, percentage of the theoretical yield of ethanol and volumetric productivity in both immobilized and free cell systems. RESULTS: The yeast cells were immobilized in Ca–alginate by an electrostatic droplet generation method. An optimal initial inoculum concentration of 2% (v/v) and optimal fermentation time of 38 h for both immobilized and free yeasts were determined. An optimal initial glucose concentration of 150 g L^?1 for free system was achieved. At the initial glucose concentration of 176 g L no substrate or product inhibition were achieved with immobilized yeast. CONCLUSION: By immobilization of the yeast into Ca–alginate using the method of electrostatic droplet generation a superior system was realized, which exhibited lower substrate inhibition and higher tolerance to ethanol. The cells of S. cerevisiae var. ellipsoideus yeast entrapped in Ca–alginate showed good physical and chemical stability, and no substrate and product diffusion restrictions were noticed. Copyright © 2008 Society of Chemical Industry     

Lipid determination in fish meal: An investigation of three standard methods applied to stabilised and non-stabilised anchovy meals at increasing stages of maturity

An investigation into the relative merits of three standard laboratory procedures for lipid determination in fish meal is described. It was found that the amount of lipid extracted by these methods from both stabilised and non-stabilised anchovy meals decreased on storage of the meals. The decrease in lipid yield as a function of the storage time may be approximated by straight lines, which reveal clear distinctions between the three methods as well as the two types of meal. The cold Bligh and Dyer method gave consistently higher lipid yields than either the hot hexane or a modified EEC method, and the decrease in the Bligh and Dyer lipid content with storage was less than that found in the hot hexane or the EEC lipid content. This difference was more pronounced in the non-stabilised than in the stabilised meals. No fundamental difference between the hot hexane and the modified EEC lipid extraction method could be established since the hydrolysis step in the EEC procedure does not de polymerise the lipid portion which is unextractable by hot hexane. The effectiveness of the antioxidant ethoxyquin in protecting polyunsaturated fatty acids in anchovy meal from oxidation is demonstrated.     

Tribological Performance of Two Potential Environmentally Friendly Ashless Vegetable Oil Additives

Two potential novel environmentally friendly ashless vegetable oil additives, 2-mercaptobenzothiazole derivatives, di-n-dodecyl-[2-(2-benzothiazolyl)thio]ethylborane (LBN) and di-n-dodecylthio-[2-(2-benzothiazolyl) thio]ethylborane (LBNS), were synthesized and their tribological performance as additives in rapeseed oil (RSO) was evaluated using a four-ball wear tester. Their anti-corrosive properties and thermal stability were also examined. The worn surface of the steel ball was analyzed by means of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that 2-mercaptobenzothiazole derivatives exhibited excellent anti-corrosive property and high thermal stability. Moreover, they both had good load-carrying capacities and anti-wear and friction-reducing properties. The PB values of samples decreased in the following order: LBNS> LBN>RSO. The results of XPS examination illustrated that the excellent tribological behavior of the prepared compounds used as additives in RSO was attributed to the formation of a protective lubrication film on the worn surface, which consisted of an adsorption layer and a reaction layer containing Fe3O4, FeS, Fe2(SO4)3, FeB, and organic nitrogen-containing compounds.     

菜籽粕水解制备复合氨基酸的研究

以菜籽粕为原料，用盐酸水解制得氨基酸液（ＡＡ），经脱色、脱酸、中和、浓缩和干燥等过程制得了氨基酸粉末。研究了影响氨基酸得率的主要因素和水解过程中氨基酸液中的异硫氰酸酯（ＩＴＣ）及口恶唑烷硫酮（ＯＺＴ）含量的变化情况。实验结果表明，使用６．０ｍｏｌ·Ｌ－１的盐酸水解菜籽粕１８ｈ，氨基酸的得率为８９．６％。氨基酸粉末中氨基酸的得率为８７．２％。制得的氨基酸粉末中异硫氰酸和口恶唑烷硫酮的含量低于饲料添加的要求     

Decreased benzo(a)pyrene concentration in rapeseed oil packed in polyethylene terephtalate

Commercially available rapeseed oil, the same oil additionally refined physically, and paraffin oil for comparison purposes were spiked with benzo(a)pyrene (BaP) at the level of 29.4, 34.3, and 50.4 µg kg^?1, respectively, filled into polyethylene terephtalate (PET) cylindrical‐shape receptacles, and the BaP concentrations were followed within 73 h by HPLC analysis. During this time, the BaP concentrations decreased to 22.9, 25.4, and 23.5 µg kg^?1 due to sorption of BaP onto PET. Using a modified kinetic equation, diffusion coefficients of BaP in all oils were calculated. The values of the diffusion coefficients and distribution coefficients indicated that other compounds present in the oils competed with BaP and affected the rate of BaP diffusion in the oils and the extent of adsorption onto PET. Moreover, the curves of BaP concentration vs. time, obtained experimentally, exhibited oscillations in BaP concentrations around the adsorption curves calculated by the kinetic equation. This was observed especially at the initial stages of the experiments, with the subsequent establishing of steady equilibrium BaP concentrations between liquid and solid phases at the end of the experiments, which does not correspond with known theory of adsorption.     

Optimization of conversion of waste rapeseed oil with high FFA to biodiesel using response surface methodology

In the present study, waste rapeseed oil with high free fatty acids (FFA) was used as feedstock for producing biodiesel. In the pretreatment step, FFA was reduced by distillation refining method. Then, biodiesel was produced by alkaline-catalyzed transesterification process, which was designed according to the 2⁴ full-factorial central composite design. The response surface methodology (RSM) was used to optimize the conditions for the maximum conversion to biodiesel and understand the significance and interaction of the factors affecting the biodiesel production. The results showed that catalyst concentration and reaction time were the limiting conditions and little variation in their value would alter the conversion. At the same time, there was a significant mutual interaction between catalyst concentration and reaction time.The biodiesel produced in the present experiment was analyzed by gas chromatography/mass spectrometry (GC/MS), which showed that it mainly contained six fatty acid methyl esters. In addition, the diesel indexes analysis showed that most of the fuel properties were in reasonable agreement with the 0# diesel standard of China (GB252-2000) and the biodiesel standard of America (ASTM D6751).     

Horn meal hydrolysate–chromium complex as a high exhaust chrome tanning agent––pilot scale studies

Acid hydrolysis of horn meal (obtained from raw horns of slaughtered cattle and buffaloes) yields a mixture of water soluble and low molecular weight peptides with average particle size of 3,838 nm (3.84 μm) and mean intensity of 5,243.7 nm (5.24 μm) and mean volume of 6,228.1 nm (6.23 μm). These peptides on reaction with Cr(III) yield a product that exhibits high exhaustion of chromium bath (above 92%) during tanning of hides and skins. To consolidate the results, the process was up-scaled in Central Leather Research Institute (CLRI) pilot plant for commercial trials. This material is applied directly to the pickled pelts at 8% w/w level and then the pelt is converted to wet blues and crust leathers. Control leathers were also processed concurrently using standard chrome tanning salts (8% w/w). Leathers showed the desired level of softness, fullness, shrinkage temperature and physical properties, and are comparable with control ones. Our results have indicated the use of Cr(III)–keratin complex could considerably reduce pollution load of Cr salts in leather processing.