Nanostructured ceria-based catalysts for oxydehydrogenation of ethane with CO2

Nanostructured cerium oxides, pure or doped with CaO, prepared from amorphous acetate precursors obtained by the freeze drying method, exhibit high surface areas and are active and selective catalysts for the oxydehydrogenation of ethane (ODE) using CO₂as an oxidant. The incorporation of Ca into a solid solution in the ceria framework reduces the activity but improves markedly the selectivity to ethene and the efficiency of CO₂. Under reaction conditions, the pure ceria was stable even at 1023 K, while the surface area of the Ca-containing sample decreased markedly. This change was accompanied by a drastic increase in the selectivity to ethene, allowing to obtain yields of ethene up to 22% with 91% selectivity.     

Influencing factors of pyrite leaching in germ-free system

The effect of mineral particle size, pulp potential and category of oxidant on pyrite leaching was studied. The results show that a smaller mineral particle size leads to a higher leaching rate of pyrite, and the optimum result with pyrite leaching rate of 2.92% is obtained when mineral particle size is less than 0.037 mm. The pulp potential reflects the leaching process. The increase of pulp potential can improve pyrite leaching. The leaching rate and velocity of pyrite can be enhanced rapidly by adding strong oxidant. The kind and the method of adding oxidant have important effect on the pyrite leaching. Appropriate concentration of Fe3 can enhance pyrite leaching but the precipitation generated by high concentration of ferric ion covers the surface of pyrites and prevents the leaching process. The leaching rate increases with the constant addition of H2O2.     

Supercritical water oxidation of nitrogen compounds with multi-injection of oxygen

A supercritical water oxidation (SCWO) process with oxidant multi-injection was studied in a continuous flow system in which the same amount of oxidant feed is split between two points – a first injection at the reactor inlet and a second injection at one of the three different positions along the reactor. Under the same operating conditions, this multi-injection configuration showed advantages over the system with a single oxidant entry. Moreover, oxidant dosage in a SCWO reactor is a key aspect in energy management.In this work, experiments were performed to find the best oxidant dosage to obtain the maximum organic conversion. Experiments were carried out using N,N-dimethylformamide (DMF) as a model compound for nitrogen-containing hydrocarbons in wastewaters. All experiments were carried out at 250 bar with an oxygen coefficient n = 1 and a temperature of 400 °C. Each experiment was carried out at five different residence times (2, 4, 6, 8 and 10 s). Once the best configuration had been determined, the effect of temperature (400–550 °C), initial organic concentration (5–30 mM), oxygen coefficient (0.5–3) and residence time (2–10 s) was investigated in the SCWO process of DMF.     

氧化剂和蛋白酶对羊毛纤维结构和性能的影响

采用氧化剂和蛋白酶处理羊毛,探讨不同改性方法对羊毛纤维表面结构和纤维性能的影响.SEM 和FrlR-ATR测试结果表明,氧化剂处理能使羊毛表面的类脂物质和胱氨酸二硫键等化学结构发生改变,鳞片钝化.随着氧化剂用量的增加.纤维的碱溶度增加,蛋白酶对碱溶度的影响较小.羊毛经改性后,纤维的回潮率与纤维的失重有关,白度的变化幅度不大,能明显提高活性染料的上染率和固着率,氧化结合蛋白酶改性技术可以替代传统的羊毛氯化改性技术.     

Comparison of the antioxidant and pro‐oxidant activities of broccoli amino acids with those of common food additives

The antioxidant and pro‐oxidant activities of broccoli amino acids were compared with those of common food additives. In decreasing order, the data showed that Asp, SMC, GABA, Glu, Gln, Pro, Phe, Leu, Lys, Arg, Asn, Val, Ile, His, Ser, Gly, Orn and Ala, when dissolved in water at concentrations of 0.5 and 0.05 mM , partially inhibited damage to deoxyribose in the presence of ferric‐EDTA and H₂O₂. In contrast, Tyr and Thr acted as pro‐oxidants in this system. The amino acids present in broccoli had no hydrogen peroxide‐scavenging effect. When dissolved in water, methanol or ethanol, SMC, Glu, Thr, Gln, Ser, GABA, Pro, Ala, Ile, Phe, Asp, Orn and Tyr inhibited lipid peroxidation. However, Asn, Val, Arg, Leu, Lys, His and Gly were not effective in decreasing peroxidation at concentrations of 0.5 and 0.05 mM . Asp > SMC > Ala > Phe > Hys > Orn > Gln = Ser > Lys > Leu = GABA = Gly > Tyr > Arg = Thr > Val > Asn > Pro > Ile > Glu (p < 0.025) showed scavenging activity towards hypochlorous acid, protecting α₁‐antiproteinase against inactivation. In this paper it has been established that some amino acids premixed with propyl gallate increase its hypochlorous acid‐scavenging capacity, while other amino acids have an additive effect with propyl gallate, permitting smaller quantities of propyl gallate to be used as food additives in some products which contain these amino acids. © 2001 Society of Chemical Industry     

新型液体汽油抗氧剂T502A的工业应用

文中介绍了一种新的液态汽油抗氧剂T502A,通过使用,试验证明该种抗氧具有与油气溶解混合效果好,使用方便,增标明显,用量少及不影响汽油其它性能指标等优点,是一种性能良好的汽油抗氧剂,其使用性能优于传统抗氧T501.     

核桃油中脂肪酸和内源抗氧化物质含量及其与氧化稳定性的相关性分析

以8个核桃品种为研究对象,有机溶剂萃取法提油,测定核桃油内源性组分（脂肪酸和内源抗氧化物质）和氧化稳定性（OSI）并对其进行相关性分析。结果表明：核桃油以不饱和脂肪酸（USFA）为主,其中以亚油酸含量最高,油酸/亚油酸比值（O/L）在0.3～0.5内;三种VE异构体按含量高低排序γ-VE>δ-VE>α-VE;甾醇含量由高到低排序为β-谷甾醇>菜油甾醇>豆甾醇;相关关系中,油酸和O/L与氧化稳定性呈极显著正相关（P<0.01,r1=0.7421,r2=0.8595）,亚油酸和多不饱和脂肪酸（PUFA）与氧化稳定性都呈极显著负相关（P<0.01,r1=-0.8457,r2=-0.9011）;核桃油氧化稳定性主要受脂肪酸影响（尤其是O/L）,其内源性抗氧化物质与油氧化稳定性并未呈现显著的相关关系。并且通过对比结果显示,新疆品种新巨丰榨取的核桃油氧化稳定性最高,相应O/L最低,适于长货架期的核桃油加工该结果将对核桃油氧化稳定性评价以及适宜制油核桃品种筛选提供一定的指导意义。     

二元合金在双氧化剂中的腐蚀动力学实例分析

提出了一种描述在双氧化剂 (X-Y) 中、且生成有外氧化膜 (AY_n) 的情况下,二元合金 (A-B) 的腐蚀模型,并利用该模型对Fe-Cr合金的腐蚀动力学实例进行了分析。表明该模型的预测可信,而氧化剂在合金中的实际扩散路径复杂且尚难预见是导致内氧化区厚度的理论计算值与实验测定值之间存在较大偏差的主要原因。     

硫酸锰为原料沉淀-氧化法制备四氧化三锰的研究

以硫酸锰、氨水为原料,空气和硝酸铵为氧化剂,通过沉淀-氧化路线制备四氧化三锰粉体。采用X射线衍射（XRD）、红外光谱（FT-IR）、扫描电镜（SEM）等手段对产物的物相、形貌特征、平均粒径进行表征。研究了硫酸锰在氨水中的水解沉淀过程以及氢氧化锰液相氧化为四氧化三锰的过程,主要研究了液相氧化过程中氧化温度、氧化时间以及随后的干燥过程对氧化的影响。实验结果表明,将硫酸锰溶液反加到氨水中的加料方式可以避免正加料方式（氨水加入到硫酸锰溶液中）形成碱式硫酸锰而造成产品中含硫量高的问题;在通空气液相氧化氢氧化锰过程中添加液相氧化剂硝酸铵可以提高氧化速率。当硝酸铵用量为3 g（硝酸铵与硫酸锰的质量比约为1∶7.5）、液相氧化温度为70 ℃、氧化时间为4 h、随后在空气中于120 ℃干燥4 h的条件下,制备的四氧化三锰产物物相纯,粒度细,硫含量低,达到电子级原料标准。     

绿色氧化剂K2FeO4对瓜尔胶的降解实验研究

瓜尔胶在油田压裂液中作为稠化剂被广泛使用,作业后的压裂返排液中瓜尔胶难以自然降解,对环境造成严重危害;探索绿色高效处理油田压裂返排液的方法成为研究的热点和难点.本实验以K2FeO4为绿色高效氧化剂,对模拟压裂返排液(质量浓度为0.3‰瓜尔胶溶液)进行了降解实验研究,结果表明,当K2FeO4用量为0.5 g/L,反应温度30 ℃,反应pH值为12.0时,溶液降黏率最大可达89.27%,COD去除率为36.27%,且氧化剂反应为三价铁离子,绿色无污染.