异丁醛一步氧化制甲基丙烯酸用杂多酸盐催化剂

采用共沉淀法制备了用于异丁醛一步氧化制甲基丙烯酸的高活性、多组分杂多酸盐催化剂．用３１Ｐ－ＭＡＳＮＭＲ，ＸＲＤ和ＩＲ等手段对所合成的杂多酸盐催化剂进行了系统的表征．结果表明，催化剂为以Ｋｅｇｇｉｎ结构钼磷酸盐为骨架的杂多酸盐．其中第一主族元素及Ｓｂ和Ｃｕ占据抗衡离子位置，Ｍｏ和Ｖ占据配位原子位置，Ｐ和Ａｓ占据中心原子位置．考察了催化剂对异丁醛一步氧化制甲基丙烯酸的催化性能．其中含Ｃｓ的杂多酸盐使目的产物甲基丙烯酸的收率最高     

异丁醛一步氧化制甲基丙烯酸的杂多酸盐催化剂的氧化还原性

异丁醛一步氧化制甲基丙烯酸的杂多酸盐催化剂的氧化还原性＊贾继飞吴通好＊＊于剑锋王国甲杨宏茂姜玉子郑莹光（吉林大学化学系，长春１３００２３）关键词异丁醛，一步氧化，甲基丙烯酸，杂多钼磷酸盐，氧化还原性异丁醛（ＩＢＡＬ）一步氧化制甲基丙烯酸（ＭＡＡ）是最...     

异丁醛一步制甲基丙烯酸催化剂的改进

以丙烯羰基合成丁辛醇的副产物异丁醛(IBD)为原料制甲基丙烯酸(MAA)是最经济的工艺路线。我们在异丁酸氧化脱氢制MAA杂多酸催化剂研究的基础上曾开展了IBD一步氧化制MAA的研究,得到IBD转化率100％,MAA单收63％,甲基丙烯醛(MAL)单收10％的结果。本文进一步改进了催化剂,取得了新的进展。     

杂多酸催化剂上乙苯的氧化脱氢

本文研究了H₃PW₁₂O₄₀及其Na⁺、Al³⁺、Cd²⁺、La³⁺盐对乙苯氧化脱氢反应的催化活性。发现活性与酸强度和酸量之间没有直接的关系。杂多酸及其盐类在反应开始阶段均存在一段活性增长期,简称为"增活期"。增活期内催化剂表面的积炭量逐渐增加,积炭物的H/C比逐渐减小。用质谱法、薄板层析法检知了积炭物中有醌类物质存在,提出了积炭物中的醌类基团是氧化肥氢的活性中心的观点。     

活性炭负载磷钨杂多酸催化合成异丁醛乙二醇缩醛

研究了负载型催化剂H3 PW12 O40/C催化合成异丁醛乙二醇缩醛的催化行为.结果表明,该催化剂在异丁醛和乙二醇的缩合反应中表现出较高的催化活性.经纯化后,异丁醛乙二醇缩醛的最终收率可达73.4％,在相同条件下催化活性优于纯H3 PW12 O40.     

丙烯选择氧化制丙烯酸杂多酸催化剂的探索

丙烯选择氧化制丙烯酸是丙烯有效利用的途径之一 .目前工业上采用两步法生产 ,即丙烯先被氧化为丙烯醛 ,丙烯醛再被氧化为丙烯酸 .两步法中所使用的催化剂多为复合氧化物[1 ] .杂多酸催化剂由于富含晶格氧 ,有可能使丙烯一步被氧化为丙烯酸 [2 ] .其中具有 Keggin结构的杂多酸易于制备 ,化学稳定性及热稳定性好 ,被广泛用作多相选择氧化反应的催化剂 .我们选取 Keggin结构的杂多酸催化剂 ,调变其阴阳离子组成 ,用于丙烯一步氧化制丙烯酸 ,并对反应条件进行了考察 .1实验部分1 .1催化剂制备含铜、铬的杂多酸催化剂的制备方法见文献[3] .将三…     

异丁醛异构化制丁酮尾气的气相色谱分析

异丁醛异构化制丁酮尾气中有CO、CO_2、H_2、C_1—C_4烃类,组分多,沸点范围广。分析这些组分文献上用多柱联合,变换柱温的色谱法,需用程序升温或采用切换装置的变温技术,设备复杂,操作烦而费时,难以应用于一般实验室。     

乙烯直接氧化制醋酸的研究 Ⅰ.Pd-Ru/杂多酸双金属催化剂上的催化性能

 考察了Pd－Ru／HPA双金属催化剂对乙烯直接氧化制乙酸反应的催化性能,以及原料气配比、反应物空速、反应压力和温度等对反应的影响．在原料气配比为V（C2H4）∶V（air）∶V（steam）＝55∶22∶23,反应物空速为4000h－1,反应压力为1．4MPa,反应温度为150～160℃时,乙烯直接氧化制乙酸反应的时空收率高达480g／（L·h）．     

杂多酸催化剂研究进展

1杂多酸概述杂多酸（Heteropolyacid）,也称多金属氧簇（Polyoxometalate）,是一类由氧原子桥接金属原子形成的金属-氧簇化合物.杂多酸具有良好的催化性能,是高效的双功能催化剂,即有酸催化性能,又具有氧化还原催化性能.杂多酸结构稳定,可以用在均相或者非均相催化环境,     

Catalyst Design for Methacrolein Oxidation to Methacrylic Acid

Heteropoly compounds (HPCs) with the general formula CsMHPVMo₁₁O₄₀are prepared and tested as catalysts. The influence of elements entering the formula on the catalyst properties is studied: Cs defines the acidity and specific area, V controls the selectivity, and the transition metal M defines the mobility of oxygen in the bulk and the catalyst activity. The mechanism of methacrolein oxidation over HPCs is investigated. Using the response method and mass spectrometry of the reaction mixture, it is shown that only the catalyst oxygen atoms take part in the formation of methacrylic acid and that the transport of active oxygen to adsorbed methacrolein plays a key role in the oxidation process. A correlation between the HPC activity and the redox ability of the metal cation M ⁿ⁺ M ^{n+ i} (i= 1 or 2) is found. New catalysts for methacrolein oxidation to methacrylic acid are developed on the basis of this correlation. These are the salts of PVMo-poly acid with Cs, Cu, and the transition metal M as cations. These catalysts are more active (a conversion of up to 91%) and selective (up to 98%) compared to conventional catalysts for methacrolein oxidation to methacrylic acid.     

二氧化碳与丙烯直接合成甲基丙烯酸用CuPMo／TiO2催化剂的研究

 用溶胶－凝胶法以磷钼酸（MPA）的铜盐溶液水解钛酸四丁酯制备了CuPMo／TiO2催化剂，并用ICP，XRD，TG－DTA，IR，TPD－MS和微反技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化性能．结果表明：杂多钼酸盐与TiO2表面通过O2－桥发生键联．在623K下，杂多阴离子仍保持其原有的Keggin结构；CO2在Lewis酸位Cu（Ⅱ）和Lewis碱位Cu－O－Mo桥氧的协同作用下形成卧式吸附态Cu（Ⅱ）←O－（CO）←（O－－Cu）；丙烯以分子吸附态在催化剂上吸附；在空速1500h－1，压力1MPa和温度563K的反应条件下，丙烯的转化率为4．2％，甲基丙烯酸的选择性为96％．     

Study of the Isothermal Bulk Polymerization of Methacrylic Acid and Some Methacrylic Acid Esters by Differential Scanning Calorimetry

Abstract

The course of the isothermal bulk polymerization of methacrylic acid and some methacrylic acid esters differing in the length of the ester group was studied by differential scanning calorimetry at different temperatures. The enthalpies of polymerization, the residual monomer content, the overall reaction rate constants, and the overall activation energies were calculated. The molecular weight averages of the synthesized polymers before and after the gel effect were measured by gel permeation chromatography.     

Study of the Isothermal Bulk Copolymerization of Acrylic and Methacrylic Acid Esters

The course and kinetics of the isothermal bulk polymerization of ethyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate and their copolymerization in different mol ratios were studied by differential scanning calorimetry at 363 K. The initiator used was 2,2′-azoisobutyronitrile. The courses of reaction, the copolymerization enthalpies, the copolymerization parameters, and the specific constants of the rate of polymerization were determined.     

Ni2（OEt）2／SiO2催化二氧化碳与丙烯直接合成甲基丙烯酸的研究

 采用表面改性法制备了负载型Ni2（OEt）2／SiO2双核金属乙氧基配合物催化剂，利用示差量热、红外光谱和微反技术对催化剂的表面结构、热稳定性、化学吸附性质和催化活性进行了研究．结果表明，负载型双核金属乙氧基配合物Ni2（OEt）2／SiO2中的Ni2＋与载体SiO2表面的O2－以双齿配位形式键合；二氧化碳在催化剂表面存在桥式吸附态和碳酸单乙酯基物种两种吸附态，丙烯则只有一种分子吸附态；在适宜的反应条件下，二氧化碳和丙烯在Ni2（OEt）2／SiO2催化剂上的反应产物主要是甲基丙烯酸．根据实验结果，提出了二氧化碳和丙烯在Ni2（OEt）2／SiO2催化剂表面的反应机理，反应物分子共吸附于催化剂表面同一活性单元上，羧酸根和丙烯解离吸附态的形成是反应顺利进行的关键步骤．     

超临界条件下CO2和丙烯直接合成甲基丙烯酸Ni2(OCH3)2/SiO2催化剂

超临界反应;负载型催化剂;双核桥联配合物;配合物;超临界条件下CO2和丙烯直接合成甲基丙烯酸Ni2(OCH3)2/SiO2催化剂     

Terpolymerization of Butadiene,Acrylonitrile, and Methacrylic Acid

Abstract

The terpolymerization of butadiene, acrylonitrile, and methacrylic acid in emulsion, using potassium persulfate as initiator and sodium dioctylsulphosuccinate as emulsifier, was investigated. For the binary system butadiene (M₁) and methacrylic acid (M₂), the following monomer reactivity ratios were determined: r₁₂ = 0.18 ± 0.05 and r₂₁ = 0.52 ± 0.09. When polymerizations were stopped at low conversions they gave terpolymers which show good agreement between experimental and theoretical copolymerization composition data, calculated from the Alfrey-Goldfinger equation. The relationships between monomer feed and terpolymer compositions are presented on triangular coordinate graphs as proposed by Slocombe. By using a computer program, the lines of unique composition and the lines of binary azeotropic composition were established. No point of true azeotropic composition was found, but a “pseudo-azeotropic” region was recognized. The influence of composition on glass transition temperature and thermal characteristics of the terpolymers is described.     

Copolymerization of Methacrylic Acid and N-Vinylpyrrolidone in Aqueous Solution

The monomer reactivity ratios for the copolymerization of methacrylic acid (MA) and N-vinylpyrrolidone (NVP) in aqueous media at 30°C were determined as a function of pH (range 2-10), by use of both the modified differential (YBR) and integrated copolymerization equation to process the data at high conversions (< 70% by weight). The reactivity ratio r₁ (for MA) ranges from 0.92 to 8.3 and that for NVP (r₂) is very small except at pH 7 and 8. The ri values show two minima: 2.9 at pH 4 and 0.92 at pH 8, nearly corresponding to the pKa values of the monomer MA and the polymer, respectively. Addition of 1 M sodium chloride results in an increase of n values, and the values are still lower than those of the undissoeiated acid. The trend of r_xwith pH is seen to follow that of the homopolymerization behavior of MA reported in the literature. The r₁ and r₂ are of the same order as those obtained in dimethylformamide in the literature.