固体碱催化酯交换反应制备生物柴油研究进展

介绍了非负载型和负载型2类固体碱催化剂用于制备生物柴油的研究进展,采用酯交换法因其无需消耗大量能量、操作方法简单,成为制备生物柴油的主要方法,并随着负载型固体碱催化剂载体的纳米化、介孔化,纳米级以及以分子筛作为载体的固体碱催化剂将成为一个主要的研究方向。认为开发更加稳定、耐水、耐酸的固体碱催化将是今后固体碱催化剂的研究重点。     

固体碱催化制备生物柴油研究进展

生物柴油是一种清洁可再生能源,是石化能源的理想替代品。近年来,生物柴油的非均相制备技术已成为研究热点,其中,固体碱催化制备生物柴油的研究较多。主要介绍了现阶段非负载型固体碱及负载型固体碱在酯交换制备生物柴油中的应用,并对用于制备生物柴油的固体碱催化剂的发展方向进行初步探讨。     

双功能催化剂镁铝固体碱负载钯的制备及应用研究

镁铝固体碱不仅具有较高的比表面积,而且具有固体碱的碱性特征。因此可以将钯负载到镁铝固体碱上,使其成为既具有钯催化效果,又具有固体碱碱性特征的双功能催化剂。镁铝固体碱可以用硝酸镁、硝酸铝和氢氧化钠与碳酸钠的缓冲液通过共沉淀法制得。而钯的负载则是用氯化钯跟制备的镁铝固体碱通过饱和浸渍法制得。苯乙酮与丁醇在水相中能够进行的烷基化反应表明,所制备的材料可以起到双功能催化剂的作用。     

负载MgO固体碱对氰乙酸乙酯脱酸精制性能研究

采用浸渍法制备出负载MgO固体碱吸附剂,利用差热-热重、X射线衍射、原子吸收光谱等方法对固体碱进行了表征,将固体碱用于氰乙酸乙酯吸附脱酸精制,考察了MgO负载量、焙烧温度对固体碱脱酸精制性能的影响,同时考察了再生后固体碱的脱酸性能。研究结果表明,负载MgO固体碱吸附剂能够有效脱除氰乙酸乙酯中的残留酸,当进料样品中酸度为58×10-6,精制后样品的酸度不大于5×10-6时,负载25%MgO固体碱脱酸精制后样品的处理量达到了200∶1(体积比),且精制后样品中金属Mg的含量不高于0.32×10-6,表明MgO具有良好的抗冲刷能力,再生后的固体碱仍具有较强的吸附脱酸能力。     

无溶剂、微波下固体碱催化酚的乙酰化反应

采用浸渍法和微波辐射法制备得到了几种以介孔氧化铝为载体的负载型固体碱催化剂。比较了这些负载型固体碱及相应无负载固体碱于无溶剂条件下对苯酚的乙酰化反应的催化效果,其中微波辐射法制备得到的碳酸钾-氧化铝（固体碱III-3）效果最好。同时对固体碱III-3催化的苯酚乙酰化反应进行条件优化,得出较优催化剂用量相对苯酚的摩尔百分比为16.8mol%、温度60℃时产率94.8%。并研究了固体碱III-3于无溶剂条件下传统加热和微波加热下对取代苯酚的乙酰化反应的催化效果,结果显示,采用传统加热法,反应时间150 min时乙酰化收率在62.0%~99.8%;而在微波辐射下,反应9 min时乙酰化收率即可达76.4%~100.0%。因此无溶剂条件下采用微波加热法用固体碱III-3催化酚的乙酰化反应是有效可行的。     

用于羟醛缩合反应的固体碱催化剂的制备及表征

采用溶胶凝胶法制备载体二氧化锆,并通过浸渍法负载铯制备固体碱催化剂,将其应用于以醋酸甲酯、甲醛为原料合成丙烯酸甲酯的反应。考察了不同温度,负载不同含量的硝酸铷、硝酸铯对催化剂性能的影响。利用微反色谱实验装置测试合成丙烯酸甲酯固体碱催化剂的催化活性,结果表明,负载铯比铷催化效果要好;催化剂最优条件：氧化锆负载20%铯,反应温度为380℃时,可使收率达到29.2%。     

用废油脂制备生物柴油的催化材料的结构与性能研究

用废油脂制备生物柴油时所用的催化剂的结构与性能研究,包括对负载型固体酸催化剂、负载型固体碱催化剂和离子液体催化剂的研究,并对生物柴油催化剂的发展进行了展望。     

活性炭负载固体碱催化剂催化制备蔗糖酯

采用等体积浸浈法制备活性炭负载固体碱催化剂,利用正交试验法优化催化剂制备条件,并考察了反应条件对蔗糖和亚油酸甲酯合成蔗糖酯产率的影响.结果表明,催化剂制备的优化条件为碳酸钾与活性炭质量比0.5,活生炭粒径350μm,浸渍时间3 h,煅烧温度500℃,煅烧时间3 h.以该条件下制备的活性炭负载固体碱为催化剂,在亚油酸甲酯...     

负载型固体碱催化合成丙二醇甲醚

将KF、KNO3、K2CO3负载在-γAl2O3、MgO、ZrO2、ZnO及镁铝复合氧化物(LDO)上制备的负载型固体碱作为催化剂,应用于甲醇与环氧丙烷合成丙二醇甲醚的实验表明,所制备的固体碱催化活性高,选择性好。     

固体催化剂催化酯交换反应制备生物柴油研究进展

酯交换法由于无需消耗大量的能量即可制备出低黏度的生物柴油,是制备生物柴油的主要方法,发展前景较好。固体催化剂催化酯交换反应产物易分离,废弃催化剂无环境污染。综述了酯交换反应制备生物柴油过程中固体催化剂的研究概况,包括固体酸和碱催化剂的研究进展,认为采用负载型固体碱催化剂催化油脂酯交换反应合成生物柴油将成为主要的研究方向。     

三氟碘甲烷气相合成催化剂分析

三氟碘甲烷是新型环保灭火剂和制冷剂的重要组分。通过对气相催化合成三氟碘甲烷催化剂的研究,发现碱金属盐的催化活性较高,对三氟碘甲烷转化率达到27%以上,在碱金属盐中,硝酸铷和硝酸铯催化的转化率可达39%,高于相应的氟化物催化活性。通过对反应前后催化剂的EDS和XPS分析发现,硝酸铷在活化过程中受热分解为亚硝酸铷,反应过程中主要生成氟氧化铷,表面约85%的Rb以氟氧化铷的形式存在;反应后催化剂的热解实验表明,表面的氟元素来自中间体二氟卡宾与活性炭的化学结合。     

Study on a novel catalytic reaction and its mechanism for CF3I synthesis

A novel vapor phase production process for CF₃I was successfully developed for the reaction between CHF₃ with I₂ in the presence of a unique catalyst. The most effective catalyst system for this reaction was found to be alkali metal salts which were supported on an activated carbon carrier. A consideration of the reaction mechanism suggests that the reaction proceeds via CF₂ carbenes formed on the catalyst surface as intermediates, followed by carbene disproportionation to CF₃ radicals, followed by reaction with I₂ to give CF₃I.     

三氟碘甲烷合成和应用研究进展

介绍了新型灭火剂和环保型制冷剂三氟碘甲烷的特性,叙述了合成路线及其应用研究进展,其中以活性炭负载碱金属或碱土金属盐为催化剂气相催化制备三氟碘甲烷法,具有工序简单、高效经济、环境污染小和易连续生产等优点,具有工业化前景.     

Effect of metal cation type on the structure and properties of ethylene ionomers

Thermal properties by DSC, stiffness, melt viscosity, tensile properties, and dynamic mechanical properties were measured for the Na⁺, K⁺, Mg²⁺, Zn²⁺, Cu²⁺, Mn²⁺, and Co²⁺ salts of poly(ethylene-co-methacrylic acid) (EMAA). The changes in the structure and properties with increasing neutralization are larger in the alkaline and alkaline earth metal salts than in the transition metal salts. The stiffness shows a maximum at 33% neutralization in both the alkaline and alkaline earth metal salts, while no maxima are found up to 60% neutralization in the transition metal salts. The microphase separation of salt group aggregates is observed in both the alkaline and alkaline earth metal salts, but is not seen in the transition metal salts. These differences were attributed to both the stronger ionic interactions and the larger number of carboxyl groups associated with the alkaline and alkaline earth metal salts in the ordered structure of ionic salt groups (ionic crystallites). The mechanical properties measured at low strain, such as stiffness and yield stress, strongly depend on the degree of the crystalline order of the ionic crystallites. The high-strain properties, such as tensile strength and elongation at break, depend on the strength of the ionic interactions and the valence of the cation.     

Synthesis of some new divalent metal salts of mono(hydroxyethyl)phthalate

Summary Divalent metal salts of mono(hydroxyethyl)phthalate (HEP) were considered to be of interest as difunctional ionic monomers and are useful for the preparation of condensation polymers. Recently, Matsuda¹ reported the preparation of Ca, Mg and Zn salts of mono-(hydroxyethyl)phthalate and their polymers^2–7. He prepared these salts by the reaction of HEP with the respective divalent metal oxides. But so far there was no report on the preparation of Pb²⁺ and Mn²⁺ salts of HEP. Since metal dicarboxylates can be obtained by the reaction of organic dibasic acids and metal acetates⁸, Pb²⁺ and Mn²⁺ acetates can similarly react with HEP to give their respective salts at the optimum temperature. We report here the synthesis and characterisation of Pb²⁺ and Mn²⁺ salts of mono(hydroxyethyl)-phthalate (HEP).     

Preparation and copolymerization of divalent metal salts of ethylene glycol–methacrylate–phthalate

Divalent metal salts of ethylene glycol–methacrylate–phthalate (EMP) were prepared by the reaction of EMP and divalent metal ions in aqueous solution. The divalent metal salts obtained, except for the Pb salt, have melting points which decrease in the order of Ca > Ba > Mg > Zn > Cd salt. The Zn and Cd salts are fairly soluble in most organic solvents. Therefore, the Zn salt and Cd salt were selected for the copolymerization with MMA, styrene (St), and hydroxyethyl methacrylate (HEMA). In the copolymerization, the rates of copolymerization increased markedly as the concentration of metal salts increased. Moreover, the systems containing MMA copolymerized more rapidly than those containing St. As for the physical properties of the copolymers obtained, compressive strength and Rockwell hardness were improved by introducing metal salts into the polymers; and heat distortion temperature and tensile and flexural strengths were also improved by selecting the most suitable concentration of metal salts according to the species of metal salts and vinyl monomers. The TGA and the boiling water resistance of the copolymers were also discussed.     

Preparation and copolymerization of divalent metal salts of ethylene glycol–methacrylate–maleate

Divalent metal salts of ethylene glycol–methacrylate–maleate (EMM) were prepared by the reaction of EMM and divalent metal ions. The divalent metal salts obtained, except for the Ba salt, have melting points which decrease in the order Pb > Ca > Cd > Mg > Zn. The Mg and Ca salts were selected for the copolymerization with MMA, styrene (St), and hydroxyethyl methacrylate. In the copolymerization, the rates of copolymerization increased markedly as the concentration of metal salts increased. Moreover, the systems containing MMA copolymerized more rapidly than those containing St. As for the physical properties of the copolymers obtained, heat distortion temperature, compressive strength, and Rockwell hardness were improved by introducing metal salts into the polymers, and tensile, flexural, and impact strengths are also able to be improved by selecting the most suitable concentration of metal salts according to the species of metal salts and vinyl monomers. Generally, Mg is more effective than Ca in improving the physical properties of the copolymers. Moreover, TGA and boiling water resistance of the copolymers are also discussed.     

Metal-carbonate formation from ammonia solution by addition of metal salts—An effective method for CO2 capture from landfill gas (LFG)

The absorption of CO₂ from LFG in different weight concentration ammonia solution and metal salts (Zinc and Barium) is investigated in this study. Addition of metal salts results in useful metal carbonates when LFG is passed through the solution. Barium salts show a better potential of removing CO₂ as compared to Zinc salts. Addition of Barium salts to ammonia solution results in a new absorbent as no study has been focused on it till date. Also metal salts are added to alkaline wastewater which not only decreases the pH of the wastewater but also useful metal carbonates are obtained from wastewater when LFG is passed through it. Different parameters like CO₂ loading, reaction rate and change in pH are investigated. Formation of carbonates is proved by using SEM and XRD analysis. Raman spectroscopy was performed on the discarded liquid after removal of carbonates to understand the formation of bicarbonates, carbonates and carbamates.     

原位氧化氯化合成3-氯丁酮

利用盐酸-过氧化氢作反应物,通过原位氯化反应合成3-氯丁酮。考察了原料配 比、反应时间、反应温度、及金属盐的加入对反应结果的影响。以CuCl2作催化剂,丁酮、盐酸、过氧 化氢的摩尔配比为2∶1∶1．3时,回流温度下反应5h,丁酮转化率为52．43％,3-氯丁酮选择性 达76％,分馏得到的产品的纯度98％以上。     

Influence of metal salts in reaction medium on performance enhancement of novel aliphatic–aromatic-based polyamide thin-film composite osmosis membranes

In this study, we report an easy and novel way to develop high flux aliphatic–aromatic-based thin-film composite (TFC) polyamide osmosis membranes by addition of inorganic metal salts with amine reactants in the reaction system of polyethylene imine (PEI) and 1,3-benzene dicarbonyl chloride. Inorganic metal salts like CuSO₄, NiSO₄, MgSO₄, and Al₂(SO₄)₃ added to block some of the amine groups of PEI through complexation which in turn changes the polycondensation reaction kinetics of amine acid chloride reaction. The prepared membranes were characterized using water contact angle and atomic force microscopy studies and the performances were evaluated both in reverse osmosis and forward osmosis mode. In presence of metal salts in reaction interface, the performance of TFC membranes was greatly enhanced and the optimum metal salt concentration was identified for individual metal salts for maximum performance enhancement. The effects of different anions for same metal ion and different molecular weight of PEI were evaluated on composite polyamide membrane performances. Water permeability (flux) of 63.48 L m^?2 h^?1 was achieved upon inorganic salt addition compared to the unmodified TFC membranes with flux of 42.1 L m^?2 h^?1 at similar salt rejection of ~95%. Based on the new findings, a conceptual model was proposed to explain the role of metal ion in amine solution on the resulting characteristics of aromatic–aliphatic type polyamide–polysulfone composite membrane.