对羟基苯甲酸-壳寡糖改性水性聚氨酯

用对羟基苯甲酸(p-HBzA)对壳寡糖(OCS)进行接枝改性,得到了对羟基苯甲酸接枝壳寡糖(p-HBz A-g-OCS)。将p-HBz A-g-OCS作为交联剂,与水性聚氨酯预聚体(PPU)聚合,合成了对羟基苯甲酸-壳寡糖改性水性聚氨酯(HOCS-WPU)。通过FTIR和UV-Vis证实了样品的结构;分别用DLS、力学性能分析、XRD、TGA、ABTS和DPPH自由基清除率对HOCS-WPU的性能进行了考察。结果显示:当加入质量分数为2%的p-HBz A-g-OCS(以合成PPU原料的总质量计)时,HOCS-WPU乳液粒径较小,为57.85nm,相比未改性WPU,HOCS-WPU胶膜的拉伸强度从14.03 MPa提高到16.85 MPa,结晶度从3.57%下降到3.45%;初始分解温度从204.6℃提高到216.7℃。自由基清除率测定结果显示:当HOCS-WPU的质量浓度为2.5 g/L时,该聚合物的ABTS和DPPH自由基的清除率分别达到了62%和35%,抗氧化活性相比未改性WPU明显提高。     

个旧有色冶化公司一期低浓度铜烟气制酸工程简介

介绍90 kt/a铜冶炼烟气制酸装置的设计和运行情况。采用三段式净化工艺与污水处理系统相结合, 有效地解决了用高砷、氟铜精砂生产硫酸的问题。采用多孔板支撑缩放管气体换热器与高蓄热能力的转化器相结合,在转化器进口平均φ(SO2)约4％,而生产负荷仅为设计能力(270t/d)的74％的条件下,转化系统仍能维持自热平衡。     

Addition of ferulic acid,ethyl ferulate,and feruloylated monoacyl- and diacylglycerols to salad oils and frying oils

To determine antioxidative effects of ferulic acid and esterified ferulic acids, these compounds were added to soybean oils (SBO), which were evaluated for oxidative stability and frying stability. Additives included feruloylated MAG and DAG (FMG/FDG), ferulic acid, ethyl ferulate, and TBHQ. After frying tests with potato chips, oils were analyzed for retention of additives and polar compounds. Chips were evaluated for hexanal and rancid odor. After 15 h frying, 71% of FMG/FDG was retained, whereas 55% of ethyl ferulate was retained. TBHQ and ferulic acid levels were 6% and <1%, respectively. Frying oils with ethyl ferulate or TBHQ produced significantly less polar compounds than SBO with no additives. Chips fried in SBO with TBHQ or ferulic acid had significantly lower amounts of hexanal and significantly less rancid odor after 8 d at 60°C than other samples. Oils were also aged at 60°C, and stability was analyzed by PV, hexanal, and rancid odor. Oils with TBHQ or FMG/FDG had significantly less peroxides and hexanal, and a lower rancid odor intensity than the control. FMG/FDG inhibited deterioration at 60°C, whereas ethyl ferulate inhibited the formation of polar compounds in frying oil. Ferulic acid acted as an antioxidant in aged fried food. TBHQ inhibited oil degradation at both temperatures. Presented at the 94th AOCS Meeting & Expo, Kansas City, MO, May 4–7, 2003.     

Penetration behavior and subsurface grafting of dansyl cadaverine and polyethylene glycol (PEG) derivatives in poly(ethylene-co-acrylic acid) (EAA) film

Dansyl cadaverine and polyethylene glycol (PEG) derivatives were grafted on the surface of EAA film and in its subsurface region through formation of amides and esters, respectively. A two-step reaction was conducted. First, EAA film was activated with PCl₅ at room temperature. Second, the acid chloride was reacted with dansyl cadaverine or a PEG derivative to form a modified film. ATR-FTIR spectroscopy and fluorometry were employed to analyze the modified films after each step. It was found that dichloromethane yielded the highest grafting efficiency, with the dansyl cadaverine penetrating throughout the ATR-FTIR analysis region (∼400 nm) in a few minutes. As the grafting depth increased with time, so did the amount of fluorescence intensity of grafted dansyl cadaverine. ATR-FTIR spectra for PEG grafting indicated that the acid chloride peak decreased with time, while the ester peak increased. However, hydrolysis occurred at later times, consuming the acid chloride groups within the film. A marked decrease of static water contact angle was observed for EAA grafted with PEG99 (PEG that contains 99 ethylene glycol repeat units), almost 40° lower than that of neat EAA (∼99°). For other PEG-grafted films, the surface hydrophilicity was also improved.     

Composition and seasonal variation of fatty acids of <Emphasis Type="Italic">Diplodus vulgaris</Emphasis> L. from the Adriatic Sea

Muscle tissue from the common two-banded sea bream Diplodus vulgaris L. originating from the Adriatic Sea, Croatia, was analyzed. The FA composition of neutral (TAG) and polar (PE, PC, PI/PS) lipid classes was determined, as well as the lipid and water contents during winter and summer periods. Both the total lipid and water contents were higher in the winter period. We identified 16 different FA. The major constituents of the total FA in both seasons were saturates: palmitic (16∶0) and stearic acids (18∶0); monoenes: oleic (18∶1n−9) and palmitoleic acids (16∶1n−7); and polyunsaturates: arachidonic acid (20∶4n−6), EPA (20∶5n−3), and DHA (22∶6n−3), but their amounts and ratios differed significantly between the two seasons and between lipid fractions. The FA composition showed a noticeable pattern of seasonality that reflected fluctuations mainly in TAG. The diminution of the monounsaturated FA content in the summer was clearly followed by an increase in PUFA content. Diplodus vulgaris is a good source of natural n−3 PUFA and would therefore be suitable for inclusion in highly unsaturated low-fat diets.     

Fatty acid composition of spanish shortenings with special emphasis on <Emphasis Type="Italic">trans</Emphasis> unsaturation content as determined by fourier transform infrared spectroscopy and gas chromatography

A Fourier transform infrared spectroscopic procedure was used to analyze 34 edible fats (22 shortenings and 12 vegetable margarines) as neat fats (IR_NF) to determine their total trans fatty acid (TFA) content. The sloping baseline was corrected with a reference spectrum based on a nonprocessed olive oil. The calibration was done using seven partially hydrogenated fats with an individual TFA content previously determined by the combination of gas chromatography (GC) with argentation thin-layer chromatography. Taking into account the different absorptivities of various trans isomers, different correction factors were calculated using the calibration standards (0.83 and 1.71 for single trans bonds in both diethylene and triethylene and for trans, trans-diethylene fatty acids, respectively) and applied to calculate the total TFA of samples. Moreover, the samples were converted to their methyl esters and reanalyzed following the same procedure (IR_FAME). Differences in TFA content of fats were not found when a t-test was used to compare the results obtained by IR_NF vs. either IR_FAME or GC, suggesting that IR of neat fats could be used, thus avoiding the need to prepare sample solutions in organic solvents and to prepare fatty acid methyl esters. The mean TFA content (determined by IR_NF) of a representative group of Spanish shortenings (22 samples) that varied widely in terms of fat sources, processes, and purposes (bakery, sandwiches, ice cream, coatings, chocolate coverings) was 6.55±11.40%, although more than 54% contained <3% of TFA. Fatty acid composition of shortenings by direct GC using a 100-m polar cyanopolysiloxane capillary column indicated that the mean trans-18∶2 isomer content was 0.58%, ranging from 0.9 to 3.4%. Small amounts of trans-18∶3 isomers (<0.3%) were observed in 18 of the 22 shortenings studied; the maximal value was <2%. The mean value of the fraction saturated+TFA of shortenings was high (59.95±12.73%), including two values higher than 83%.     

Plackett-burman design for determining the preference of Rhizomucor miehei lipase for FA in acidolysis reactions with coconut oil

The preference of lipase (EC 3.1.1.3) from Rhizomucor miehei in the incorporation of 11 FA, ranging from C10∶0 to C22∶6, into coconut oil TAG during acidolysis was studied by applying the Plackett-Burman experimental design. Enzymatic acidolysis reactions were carried out in hexane at 37°C for 48 h with coconut oil (0.1 M) and a mixture of 11 FA at a TAG to FA molar ratio of 1∶1. Lipase was used at the 5 wt% level. The incorporation of FA into coconut oil TAG was determined by GC. The lipase showed preference for long-chain saturated FA for incorporation into coconut oil TAG. The FA with 18 carbon atoms showed a high incorporation rate (18∶1>18∶1>18∶3). The lipase showed the least preference for the incorporation of 12∶0, which occurs in maximal concentration (46%), whereas the most preferred FA, 18∶0, occurs at a very low concentration (<2%) in coconut oil. The overall preference of lipase for the incorporation of different FA into coconut oil TAG was 18∶0>18∶2, 22∶0>18∶1, 18∶3, 14∶0, 20∶4, 22∶6>16∶0>12∶0≫10∶0.     

Performance evaluation of hexane-extracted oils from genetically modified soybeans

Soybeans produced by induced mutation breeding and hybridization were cracked, flaked and hexane-extracted, and the recovered crude oils were processed to finished edible oils by laboratory simulations of commercial oil-processing procedures. Three lines yielded oils containing 1.7, 1.9 and 2.5% linolenic acid. These low-linolenic acid oils were evaluated along with oil extracted from the cultivar Hardin, grown at the same time and location, and they were processed at the same time. The oil from Hardin contained 6.5% linolenic acid. Low-linolenic acid oils showed improved flavor stability in accelerated storage tests after 8 d in the dark at 60°C and after 8h at 7500 lux at 30°C, conditions generally considered in stress testing. Room odor testing indicated that the low-linolenic oils showed significantly lower fishy odor after 1 h at 190°C and lower acrid/pungent odor after 5 h. Potatoes were fried in the oils at 190°C after 5, 10 and 15 h of use. Overall flavor quality of the potatoes fried in the low-linolenic oils was good and significantly better after all time periods than that of potatoes fried in the standard oil. No fishy flavors were perceived with potatoes fried in the low-linolenic oils. Total volatile and polar compound content of all heated oils increased with frying hours, with no significant differences observed. After 15 h of frying, the free fatty acid content in all oils remained below 0.3%. Lowering the linolenic acid content of soybean oil by breeding was particularly beneficial for improved oil quality during cooking and frying. Flavor quality of fried foods was enhanced with these low-linolenic acid oils.     

Analysis of epoxidized soybean oil by gas chromatography

A fast and cost-effective procedure to quantitate epoxidized soybean oil by means of an external standard method is reported. This procedure is applicable to commercial epoxidized oils, polymer additive packages and polymers—polyvinyl chloride (PVC)—containing epoxidized oils. The epoxidized soybean oil is converted into fatty acid methyl esters with tetramethylammonium hydroxide, and analyzed by capillary gas chromatography with flame-ionization detection. In PVC samples, the epoxidized soybean oil was extracted with toluene and followed by derivatization prior to analysis. The methyl esters of monoepoxyoctadecanoic, diepoxyoctadecanoic and triepoxyoctadecanoic acid were separated with a short capillary column.     

New acid catalyst comprising heteropoly acid on a mesoporous molecular sieve MCM-41

New solid acid catalysts, consisting of heteropoly acid (HPA) H₃PW₁₂O₄₀ (PW) supported on a mesoporous pure-silica molecular sieve MCM-41, have been prepared and characterized by nitrogen physisorption, X-ray diffraction, FT-IR, and³¹P magic angle spinning NMR. The PW/MCM-41 compositions with PW loadings from 10 to 50 wt% have 30 Å uniformly-sized mesopores. HPA retains the Keggin structure on the MCM-41 surface and forms finely dispersed HPA species. No HPA crystal phase is developed even at HPA loadings as high as 50 wt%. PW/MCM-41 exhibits higher catalytic activity than H₂SO₄ or bulk PW in liquid-phase alkylation of 4-t-butylphenol (TBP) by isobutene and styrene. In the alkylation of TBP by styrene, PW/MCM-41 shows a size selectivity compared to bulk PW and PW/SiO₂, providing higher yields of a 2-(1-phenylethyl)-4-t-butylphenol, at the expense of the more bulky 2,6-bis-(1-phenylethyl)-4-t-butylphenol. The PW/MCM-41 compositions, having strong acid sites and a regular mesoporous system, are promising catalysts for the acid-type conversion and formation of organic compounds of large molecular size.