腐殖土理化性质的研究

采用扫描电镜、傅立叶红外光谱、电感耦合等离子发射光谱仪等对腐殖土的理化性质进行研究。腐殖土干态下的平均粒径223μm,湿态粒径66.5μm,干腐殖土的密度约为2.47g/cm3,结构疏松多孔。当腐殖土与水充分接触后,其有机质和固体物质仅有微小的溶解。腐殖土与去离子水接触后,钙、镁元素会析出,接触时间小于2h时,析出的钙、镁元素随着接触时间的增加而增加,当接触时间超过2h后,钙、镁元素溶出的量几乎不再增加。腐殖土含有羧基、羟基等官能团,这些都将影响活性污泥的性质。     

Oxidative stability of soybean oil fatty acid methyl esters by oil stability index (OSI)

Biodiesel, an alternative diesel fuel derived from transesterification of vegetable oils or animal fats, is composed of saturated and unsaturated long-chain FA alkyl esters. During long-term storage, oxidation caused by contact with air (autoxidation) presents a legitimate concern with respect to monitoring and maintaining fuel quality. Extensive oxidative degradation may compromise quality by adversely affecting kinematic viscosity, acid value, or PV. This work examines the oil stability index (OSI) as a parameter for monitoring the oxidative stability of soybean oil FAME (SME). SME samples from five separate sources and with varying storage and handling histories were analyzed for OSI at 60°C using an oxidative stability instrument. Results showed that OSI may be used to measure relative oxidative stability of SME samples as well as to differentiate between samples from different producers. Although addition of α-tocopherol or TBHQ increased OSI, responses to these antioxidants varied with respect to SME sample. Variations in response to added antioxidant were attributed to aging and other effects that may have caused oxidative degradation in samples prior to acquisition for this study. Results showed that OSI was more sensitive than iodine value in detecting the effects of oxidative degradation in its early stages when monitoring SME during storage.     

Thermal stability ofThevetia peruviana juss seed oil

Thevetia peruviana seed showed characteristic changes in physicochemical properties when heated at 180, 200, and 220°C over a period of 15 h. There is no striking significant difference in the five parameters (iodine value, acid value, peroxide value, saponification value, and polar compounds) studied for the three working temperatures. Thevetia seed oil showed good thermal stability and will be a good frying and cooking oil.     

Determination of oxidation stability of soybean oil with the oxidative stability instrument: Operation parameter effects

Operation parameters of the oil stability index instrument were evaluated to determine their effect on the oxidative stability of commercial soybean oil. A factorial design was developed to evaluate the following three parameters, each at two levels, sample weight (2.5 or 5.0 g), conductivity tube temperature (20 or 30°C), and air flow rate (12 or 20 L/h), for a total of eight observations. Significance testing indicated that sample size and air flow rate affected oil oxidative stability independently (P<0.001), but not in combination. The conductivity tube temperature did not affect the oxidation stability index. Presented at the 1993 American Oil Chemists’ Society Meeting in Anaheim, California.     

Frying stability of high-oleate and regular soybean oil blends

The objective of this work was to study the frying stability of soybean oil (SBO) with reduced linoleate (18∶2) and linolenate (18∶3) and elevated oleate (18∶1) contents. High-oleate SBO [HO SBO, 79% oleic acid (OA)] and a control (conventional SBO, 21.5% OA) were tested as is, as well as blended in different ratios to make three blended oils containing 36.9, 50.7, and 64.7% OA, abbreviated as 37%OA, 51%OA, and 65%OA, respectively. In addition, a low-linolenate (LL) SBO containing 1.4% 18∶3 and 25.3% 18∶1 was tested. Bread cubes (8.19 cm³) were fried in each of 18 oils (6 treatments×3 replicates). We hypothesized that stability indicators would be indirectly related to the total 18∶2 plus 18∶3 percentages and/or the calculated oxidizability. In general, the results were fairly predictable based on total 18∶2 and 18∶3 concentrations. The overall frying stability of the six oil treatments, from the best to the poorest, was: 79%OA, 65%OA, 51%OA, LL≥37%OA, and the control, with respective total compositions for 18∶2 plus 18∶3 of 10.3, 23.6, 36.3, 59.6, 48.9, and 62.8%. The greatly reduced concentration of 18∶3 in the LL SBO made it more stable than the 37%OA, even though the combined composition of 18∶2 and 18∶3 of LL was greater than that of the 37%OA. Blending conventional SBO with HO SBO had a profound effect on the oxidative stability index and color of the blended oils, but the values were not linearly predictable by the percentage of control in the blended oil. Other stability indices, including calculated oxidizability, calculated iodine value, conjugated dienoic acid value, and viscosity, changed in linear response to an increased proportion of the control in the blends.     

Long storage stability of biodiesel made from rapeseed and used frying oil

The degree of physical and chemical deterioration of biodiesel produced from rapeseed and used frying oil was studied under different storage conditions. These produced drastic effects when the fuel was exposed to daylight and air. However, there were no significant differences between undistilled biodiesel made from fresh rapeseed oil and used frying oil. The viscosity and neutralization numbers rose during storage owing to the formation of dimers and polymers and to hydrolytic cleavage of methyl esters into fatty acids. However, even for samples studied under different storage conditions for over 150 d the specified limits for viscosity and neutralization numbers had not been reached. In European biodiesel specifications there will be a mandatory limit for oxidative stability, because it may be a crucial parameter for injection pump performance. The value for the induction period of the distilled product was very low. The induction period values for the undistilled samples decreased very rapidly during storage, especially with exposure to light and air.     

Anchovy oil thermal polymerization kinetics

The thermal polymerization reaction kinetics of anchovy oil was investigated with and without catalyst. In order to make a comparison, linseed oil was included in the study. Reactions were carried out 260, 270, and 280°C, and a kinetic model was determined for each case. The reactions for linseed oil with and without catalyst at all temperatures followed the first-order kinetics. In the case of anchovy oil, the best-fitted straight line is obtained by plotting viscosity values against time, and the reaction proceeds in two stages at 280°C without catalyst. The use of catalyst lowered the temperature to 270°C for the appearance of two different rates. Additionally, some mathematical equations were derived between iodine value, refractive index, viscosity, and reaction time.     

苯基硅油的合成、结构表征与性能比较

将甲基苯基二甲氧基硅烷和二苯基二乙氧基硅烷分别与二甲基二甲氧基硅烷共水解,在三氟甲磺酸催化下平衡缩聚,合成了两种不同苯基摩尔分数的苯基硅油.研究了苯基摩尔分数、摩尔质量对苯基硅油热稳定性、折射率和流变性能的影响.结果表明,随着苯基摩尔分数的提高,苯基硅油的折射率提高;当苯基摩尔分数为25％～30％时,二苯基硅油的热稳定...     

Pan-frying stability of NuSun oil,a mid-oleic sunflower oil

Pan-frying is a popular frying method at home and in many restaurants. Pan-frying stabilities of two frying oils with similar iodine values (IV)—mid-oleic sunflower oil (NuSun oil; IV=103.9) and a commercial canola oil (IV=103.4)—were compared. Each oil sample was heated as a thin film on a Teflon-coated frying pan at ∼180°C to a target end point of ≥20% polymer. High-performance size-exclusion chromatography analysis of the mid-oleic sunflower and canola oil samples indicated that the heated samples contained 20% polymer after approximately 18 and 22 min of heating, respectively. The food oil sensor values increased from zero to 19.9 for the canola sample and from zero to 19.8 for the mid-oleic sunflower sample after 24 min of heating. The apparent first-order degradation rate for the mid-oleic sunflower sample was 0.102±0.008 min⁻¹, whereas the rate for the canola sample was 0.092±0.010 min⁻¹. The acid value increased from approximately zero prior to heating to 1.3 for the canola sample and from zero to 1.0 for the mid-oleic sunflower sample after 24 min of heating. In addition, sensory and volatile analyses of the fried hash browns obtained from both oils indicated there were no significant differences between the two fried potato samples.     

Effect of structure of aromatic diamines on curing characteristics,thermal stability,and mechanical properties of epoxy resins. I

The curing behavior of diglycidyl ether of bisphenol-A (DGEBA) with aromatic diamines having aryl–ether, aryl–ether–carbonyl, and aryl–ether–sulfone linkages was studied using differential scanning calorimetry (DSC). Aromatic diaminessuch as 1,3-bis(aminophenoxy)benzene (R), 1,4-bis(aminophenoxy)benzene (H),2,2′-bis[4-(4-aminophenoxy)phenyl]propane (B), 4,4′-bis(4-aminophenoxy)benzo-phenone (P), and bis[4-(4-aminophenoxy)phenyl]sulfone (S) were synthesized and characterized in the laboratory. Curing of DGEBA was done using both stoichiometric and nonstoichiometric amounts of diamines and the reaction was monitored using DSC. The reactivity of the diamines depended on the structure. The presence of electron withdrawing groups, even though significantly apart from the reaction site, reduced the nucleophilicity. No significant change was observed in the activation energy for curing, which was around 56 ± 2 kJ/mol. The glass transition temperature of the epoxy network depended on the structure and was higher when diamines P and S were used in comparison to diamines R, H, and B. The cured resins were stable up to 300°C, and maximum char yield (i.e., 32% at 600°C) was obtained in DGEBA cured with diamine P. The room temperature mechanical properties only changed marginally with the structure of the diamines. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1759–1766, 1998     

新型稠油采收降黏助剂的研制和应用

研制了稠油采收降黏助剂,表面活性剂单体选用了主要成分为木质素磺酸盐的造纸废液作为分散剂,减少了环境污染。配方定型和配方复配中,将降黏剂改为两剂型,有效利用了溶解热。对该降黏剂进行了稠油乳化降黏实验,稠油黏度由8371mPa·s降至23,2mPa·s,总降黏率达99％以上。室内和现场实验效果良好,解决了稠油采收的难题,提高了稠油油藏的采收率。     

Establishment of a model substrate oil for antioxidant activity assessment by oil stability index method

A model substrate oil using methyl linoleate was established for the determination of the antioxidant activity by Oil Stability Index (OSI) method. OSI values for methyl linoleate with different concentrations (5–100%) in silicone oil were measured at different temperatures (70–120°C). As the temperature increased, the OSI value decreased in each concentration of methyl linoleate. Optimal temperature and concentration of antioxidants, α-tocopherol, and butylated hydroxytoluene on OSI values for 10% methyl linoleate model oil was measured at 90, 100, 110, and 120°C. The logarithmic relationship between temperature and OSI using model substrate oil was similar to that of soybean oil. Furthermore, application of some spice extracts to this model oil system was carried out to give results thhat compared well with those available in the literature. Thus, the procedure using methyl linoleate-silicone oil as a model substrate oil is available for evaluating the antioxidant activity by the OSI method.     

Supercritical fluid extraction of jojoba oil

Supercritical fluid extraction of jojoba oil from Simmondsia chinensis seeds using CO₂ as the solvent is presented in this study. The effects of process parameters such as pressure and temperature of extraction, particle size of jojoba seeds, flow rate of CO₂, and concentration of entrainer (hexane) on the extraction yield were examined. Increases in the supercritical CO₂ flow rate, temperature, and pressure generally improved the performance. The extraction yield increased as the particle size decreased, indicating the importance of decreasing intraparticle diffusional resistance. The maximum extraction yield obtained was 50.6 wt% with a 0.23-mm particle size and a 2 mL/min CO₂ flow rate at 90°C and 600 bar. Use of an entrainer at a concentration of 5 vol% improved the yield to 52.2 wt% for the same particle size and also enabled the use of relatively lower pressure and temperature, i.e., 300 bar and 70°C.     

Oil stability index correlated with sensory determination of oxidative stability in canola oil

The usefulness of the Oil Stability Index (OSI) as an accelerated oxidative stability test for canola oil was studied by correlating the OSI with the induction period as determined by sensory analysis. Canola oil was treated by holding it for differing times (0, 1, 2, 3, 4, and 6 d) at elevated temperature (60°C) in the dark with agitation. The sensory induction period (SIP) was determined by storing the five treatments of oil and the control at 60°C in the dark with agitation and removing aliquots of oil for a nine-member sensory panel to evaluate over a 9-d period. The time it took for a treatment to reach an average sensory score of 5 (10-point scoring scale) was defined as the treatment’s SIP. OSI values were obtained on day 0 using a heating block temperature of 110°C and an air pressure of 6 psi. The relationship between SIP and OSI had a 0.89 coefficient of determination (r ²). This relationship may be sufficiently strong to warrant use of the OSI in industry applications but may not be ideal for more precise experimental studies of canola oil shelf life.     

Extraction of oleic acid from soybean oil and jojoba oil-phase diagrams

Formamide,N-methylformamide,N-dimethylformamide, dimethylsulfoxide, 1,2-butanediol, and 2-butane-1,4-diol were considered as potential extractants of fatty acids from soybean and jojoba oils. Ternary liquid-liquid phase diagrams at 298.15 K, distribution, and selectivity coefficients of oleic acid are reported. Of the investigated solvents, onlyN-methylformamide and 1,2-butanediol have desirable extraction characteristics.     

聚吡咯纳米线的合成及热稳定性研究

以阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)为软模板,磷酸(PA)、苯甲酸(BA)和乙酸(EA)为掺杂剂,通过化学氧化法合成了直径为40～90 nm的聚吡咯(PPy)纳米线,通过热重分析(TGA)系统地研究了有机酸(BA,EA)、无机酸(PA)、CTAB和PA的浓度以及反应温度对PPy纳米线热稳定性的影响,同时对形成机理进行了探讨。结果表明,刚性结构的有机酸和多元无机酸掺杂的PPy纳米线的热稳定性最好。     

Solubilization of lycopene in jojoba oil microemulsion

The unique properties of jojoba oil make it an essential raw material in the manufacture of cosmetics. New, totally dilutable U-type microemulsions of water, jojoba oil, alcohols, and the nonionic surfactant polyoxyethylene-10EO-oleyl alcohol (Brij 96V) have been formulated recently. Here, these microemulsions are shown to be capable of solubilizing lycopene, a nutraceutical insoluble in water and/or oil, much more effectively than the solvent (or a solvent and surfactant blend) can dissolve them. In water-in-oil (W/O) and oil-in-water (O/W) microemulsions with 10 and 90 wt% water, respectively, the normalized maximal solubilization efficiency α is ca. 20-fold larger than its solubility. The solubilization capacity of the system is mainly surfactant-concentration dependent. The lycopene resides at the interfaces of the W/O and O/W microemulsions and engenders significant structural changes in the organization of the microemulsion droplets. In the absence of lycopene, the droplets are spherical; when lycopene is added, compaction of the droplets and formation of threadlike droplets are observed. On further addition of lycopene, the bridging effect wanes and the droplets revert to a spherical shape. The enhanced solubilization demonstrated for lycopene opens up new options for formulators interested in making liquid and transparent products for cosmetic or pharmaceutical uses.     

提高润滑油基础油氧化安定性的方法

南阳石蜡精细化工厂由于在南阳稀油中掺炼南阳稠油,使润滑油基础油氧化安定性变差。本文介绍了南阳混合原油润滑油基础油性质及氧化安定性与油品组成的关系。通过对提高糠醛溶剂精制深度、对精制溶剂的改性、糠醛溶剂加入抗氧剂、WSQ—2脱氮剂液相脱氮工艺等方法的比较,探讨了如何利用现有装置改善基础油氧化安定性的途径。     

添加剂对柴油机润滑油油水界面性质及乳状液稳定性的影响

测定了柴油机油模拟油/蒸馏水体系的界面张力、界面剪切粘度和乳状液稳定性。结果表明,含有添加剂T154的柴油机油模拟油与蒸馏水间的界面张力明显低于无添加剂的体系的界面张力,界面剪切粘度增加,乳状液特性值比模拟油/蒸馏水体系稍大,乳状液稳定性增加;添加剂T109却使模拟油与蒸馏水体系的界面张力增大,界面剪切粘度降低,乳状液特性值比模拟油/蒸馏水体系小,乳状液稳定性降低,有一定的破乳作用。     

硝酸铵的热稳定性研究

分析了硝酸铵热分解的机理及影响因素,介绍了测定硝酸铵热稳定性的方法及其优缺点。结果发现,加速度量热仪和C80微热量热法是目前最安全、简便、实用的反应性化学物质热危险性的评价方法。研究结论为解决硝酸铵生产、储存和运输过程中的安全问题提供了重要参考。