The production of high efficiency Ziegler–Natta catalyst with dual active sites nature using cyclohexyl chloride as promoter with super activity and produced superior polyethylene with controllable molecular weight distribution

In the previous studies, the several halocarbons (HC) were tested as promoters for a Ti-based Ziegler–Natta (ZN) catalyst at different polymerization conditions. The Results showed that chloro cyclohexane has the best operation in catalyst activity, polymer particle size growth, hydrogen responsibility and wax reduction too. For the first time in this study, the effect of Al/Ti ratio on the optimum HC/Ti ratio has been considered and the results showed that the optimum HC/Ti ratio depends on the Al/Ti ratio directly. In the optimum HC/Ti ratio, the catalyst activity and hydrogen responsibility ratio of the catalyst increase up to 125 and 55% respectively. The acceptable growth of polymer powder up to 46%, lower flow rate ratio (FRR) up to 19% and decrease of wax amount up to 12%, completed the promotion results. Furthermore, in the next part of this study and as key note, a little dose of halocarbon was used in the catalyst preparation to produce the special catalysts with dual active sites. In the catalyst preparation, the concentration of each active sites depends on the halocarbon amount and it can control the molecular weight distribution of the produced polyethylene; because each active sites have different response to hydrogen. The halocarbon based catalysts showed the remarkable effect on the catalyst activity, the molecular weight and especially molecular weight distribution (MWD). The flow rate ratio and MWD could be increased up to 77 and 88% respectively as the main result of halocarbon addition during the catalyst preparation.     

固体超强酸SO2-4/TiO2催化合成乙酸环己酯

以乙酸和环己醇为原料，用不同晶型纳米TiO2制备的SO4^2-／TiO2超强酸为催化剂合成乙酸环己酯。考察了不同晶型纳米TiO2制备超强酸催化活性、催化剂活化温度、催化剂的用量、反应物摩尔比等因素对收率的影响。实验结果表明，较适宜条件为：锐钛型纳米TiO2制备超强酸，环己醇的用量在0．4mol的情况下，催化剂活化温度450℃、催化剂的用量1．50g，环己醇与乙酸的摩尔比1：2，酯收率达95．6％。     

苯酚丙酮装置CHP浓度测定方法评价

评价了苯酚丙酮装置生产过程中液体过氧化氢异丙苯（CHP）浓度的测定方法，通过对其测定条件的讨论，指出不同CHP浓度的液体试样，其测定条件应有所不同，在此基础上对原测定方法进行了修正。     

Fluorescence densitometry at polymer-polymer interfaces: interdiffusion in polystyrene-poly(cyclohexyl methacrylate) blends

An experimental set-up is described to determine the concentration profile of a polymer labelled with a fluorescent dye at the interface with a compatible unlabelled polymer. This method is applied to a study of interdiffusion in blends of labelled polystyrene with poly(cyclohexyl methacrylate) and compared with tracer diffusion of labelled polystyrene in the same system.     

肉桂酸环己酯的催化合成

采用中孔分子筛MCM-41为催化剂,用环己醇和肉桂酸为原料合成了肉桂酸环己酯.考察了催化剂用量、反应物物质的量比、反应温度和反应时间对肉桂酸转化率的影响.通过试验得出该反应最佳的合成条件是:肉桂酸和环己醇的物质的量配比为1∶4,催化剂的量为肉桂酸质量的2.5％,反应时间为3h,反应在剧烈回流温度下进行.在此条件下,肉桂酸的转化率可达89.1％,纯度大于99.5％.反应条件温和,操作简单,产物提纯容易,具有工业化应用前景.     

A simple and quick determination of aldehydes in autoxidized vegetable and fish oils

A simple and quick method for the quantitative determination of aldehydes in oxidized oils was established. The analysis was based on the reaction of N,N-dimethyl-p-phenylenediamine (DPPD) with aldehydes in the presence of acetic acid. Reaction products were determined by visible absorption at wavelengths of 400, 460 and 500 nm. The errors of the DPPD method in the analyses of total aldehydes in authentic mixtures of various aldehydes were less than 5%, and this method could be used successfully to determine aldehyde contents in oxidized vegetable and fish oils. The reaction time of the DPPD method (10 min at 30°C) is much shorter than that of the conventional method that uses 2,4-dinitrophenylhydrazine as a reagent (30 min at 60°C). The simplicity of the procedure enables a quick determination of aldehyde contents in oxidized oil samples.     

新型交联剂双叔丁基过氧化二异丙苯的合成研究

以对(间)二异丙苯为原料经过过氧化反应、还原反应、双叔丁基过氧化二异丙苯(BIPB)的合成三步反应合成双叔丁基过氧化二异丙苯。研究了物料配比、温度、时间、压力、搅拌装置等条件对合成交联剂BIPB的影响,确立了产品的质量指标,得到了优惠反应条件:以空气作为氧化剂,过氧化时间60 h,反应压力1.0 MPa,过氧化温度120°C,以亚硫酸钠作为还原剂。在硫酸介质中合成BIPB。总收率≥63.5%(以二异丙苯计)。     

树脂催化分解过氧化氢异丙苯制苯酚丙酮

研究了树脂催化剂类型的选择,树脂易破碎的原因,反应液中同含量对反应的影响,以及树脂的失活与再生方法。得出最佳反应条件是：采用CT-175强酸性阳离子交换树脂作为催化剂,分解温度为65-70℃,反应压力为常压;失活树脂用摩尔分数为3．5％的硫酸溶液再生。同时,采用了循环流化床反应器进行小试实验。     

Horseradish peroxidase degrades lipid hydroperoxides and suppresses lipid peroxidation of polyunsaturated fatty acids in the presence of phenolic antioxidants

Linoleic acid hydroperoxide (LAOOH) was effectively degraded by horseradish peroxidase (HRP) in the presence of quercetin. Several natural phenolic antioxidants, such as quercetin, capsaicin, and alpha-tocopherol, acted as good hydrogen donors in the peroxidase reaction that occurs during lipid hydroperoxide degradation. However, glutathione, which is a non-phenolic antioxidant that acts as a hydrogen donor for glutathione peroxidase, could not suppress lipid peroxidation in the presence of HRP. Lipid hydroperoxides generated from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were also degraded with HRP in the presence of quercetin, and oxidative decomposition of DHA was suppressed by this reaction.     

Autoxidation of synthetic isomers of triacylglycerol containing eicosapentaenoic acid

Several triacylglycerols (TAG) that contained eicosapentaenoic acid (EPA) were chemically synthesized and stored at 25°C to assess the influence of TAG structure on oxidative stability and formation of oxidation products. Oxidative stability was evaluated by oxygen consumption during storage of the TAG. Autoxidation products of TAG were analyzed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Results showed that a 2:1 (mole/mole) mixture of trieicosapentaenoylglycerol (EEE) and tripalmitoylglycerol (PPP) was most susceptible to autoxidation. The oxidative stability of TAG that contained EPA and palmitic acid was negatively correlated with the moles of EPA in a single TAG molecule. When TAG with one EPA and two other fatty acids were oxidized, chainlength of constituent fatty acids hardly affected the oxidative stability of EPA-containing TAG molecules, except for stearic acid. HPLC and LC-MS analyses showed that monohydroperoxides were major oxidation products regardless of type of TAG. Bis- and tris-hydroperoxides were formed during autoxidation of EEE and dieicos-apentaenoylpalmitoylglycerol. Monohydroperoxy epidioxides were found in all autoxidized TAG. These observations suggested that TAG structure affected the oxidation of TAG with highly unsaturated fatty acids.