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以乙炔和醋酸为原料,采用工业用醋酸锌/活性炭为催化剂,在微型固定床反应器中系统地考察了常压下空速、催化剂粒径、温度和乙炔与醋酸物质的量之比对醋酸乙烯合成的影响.结果表明,以粒径为0.177~0.250 mm的醋酸锌/活性炭为催化剂,乙炔与醋酸物质的量之比2.4~6.4,常压,温度150~225℃和空速900~5 000 h-1的条件下反应,反应器内外扩散阻力可忽略,催化剂具有良好的催化活性和稳定性.采用幂函数模型研究该条件下乙炔法合成醋酸乙烯的本征动力学,复相关指数达0.962 1,乙炔法合成醋酸乙烯过程中乙炔的反应级数为1.0,醋酸的反应级数为-0.5,指前因子为0.152 5(mol0.5m1.5)/(kg·s),反应活化能为8.767 3×104J/mol. 相似文献
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通过对乙炔法合成醋酸乙烯的反应因素进行分析,结合生产运行实际情况,提出工艺改进措施,提高醋酸乙烯产量,达到提高设备利用率的目的. 相似文献
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采用具有表面皱褶的多孔碳小球(PCS)负载醋酸锌(PCS-Zn),在温和条件下催化乙炔与醋酸反应生成醋酸乙烯(VAc)。反应温度220℃时醋酸与乙炔的单程转化率分别为22.6%与5.3%,生成VAc的活性大于1000g·mol-1·h-1。 相似文献
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以炭小球(SAC)为载体,采用过量浸渍法制备了不同醋酸锌负载量的醋酸锌/炭小球催化剂,在常压固定床反应器上,考察了醋酸锌负载量、反应温度、乙炔和醋酸摩尔比、空速等因素对乙炔合成醋酸乙烯的影响。采用SEM,BET,XRD等表征手段研究了催化剂活性降低的机理。研究表明,活性组分的流失和反应过程中形成的少量积炭是催化剂活性下降的2个重要原因。当催化剂中醋酸锌负载量(质量分数)为32.05%,常压,反应温度220℃,C2H2/HAc摩尔比为3∶1,乙炔体积空速为500 h-1,反应110 h后,醋酸的单程转化率为24.20%,醋酸乙烯选择性为98.50%,醋酸锌/炭小球催化剂催化合成醋酸乙烯的生产能力可达2.95 g/(mL.d),比高比表面活性炭催化剂的生产能力高35.32%,且该催化剂具有良好的催化活性、醋酸乙烯选择性和反应稳定性。 相似文献
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采用混合法制备La0.8K0.2Mn0.95Cu0.05O3/γ-Al2O3担载型钙钛矿型催化剂,担载前载体于0.5 mol/L的H2SO4溶液中进行浸渍改性。运用程序升温氧化对各担载型催化剂进行活性评价,考察载体改性时间对催化剂活性的影响。采用XRD和FTIR对催化剂进行了表征,结果显示,改性后的担载型催化剂能够保持良好的钙钛矿结构;与6 h和24 h的相比较,发现载体γ-Al2O3经过12 h浸渍改性后,混合法制备的担载量为20%的担载型催化剂表现出较好的催化活性,将碳烟的起燃温度降至389℃,该温度在柴油车排气温度范围内。 相似文献
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改进的柠檬酸络合法制备了ZnFe2O4/ZnO催化剂,并用于乙二胺和2,3-丁二醇环化脱氢制备烷基吡嗪。用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)对催化剂进行了表征。考察了Zn/Fe摩尔比、反应温度、载气空速对2,3-丁二醇转化率和烷基吡嗪选择性的影响。结果表明,在n(Zn)∶n(Fe)=2∶1、反应温度380℃、原料液流速0.02 mL/min、载气空速1 440 h-1时,2,3-丁二醇的转化率为93.38%,烷基吡嗪的收率为85.47%,其中,2,3-二甲基吡嗪的收率为22.16%、2-甲基吡嗪的收率为63.31%。 相似文献
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醋酸乙烯CT-2型催化剂使用寿命的预测 总被引:3,自引:0,他引:3
本文对已在工业装置上分别应用一年和两年的醋酸乙烯CT-2型催化剂,进行了分区分层取样,对所获样品进行了各种物化性能和机械性能的测定,并将测定结果与工业运转的实际情况进行关联认为CT-2型催化剂失活的主要原因是:(1)由于Pd-Au粒子的长大使其分散度下降,树脂状物及结焦的存在,使催化剂的比表面和孔容降低.在此基础上预测已反应17665小时的CT-2型催化剂的使用寿命尚可延长一年。 相似文献
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In this paper, density functional theory (DFT) was used to study the possibility of low-dimensional (2D, 1D, 0D) boron nitride nanomaterials to catalyze acetylene acetate reaction, and further explore the possible source of this catalytic activity. It is found that the catalytic activity of boron nitride nanomaterials for acetylene acetate reaction will change with the change of the geometric structure (dimension) and reaction site of the catalyst. From the geometric structure, the reaction components and the zero-dimensional BN catalyst can form chemical bonds and form complexes, while only physical adsorption occurs on the surface of the one-dimensional and two-dimensional BN catalysts. From the reaction site, the properties of different C sites on the B12N12NC-C2H2 complexes are different. Namely, a C atom connected with a B atom is more likely to have an electrophilic reaction with H+, and a C atom connected with an N atom is more likely to have a nucleophilic reaction with CH3COO−. Through the study of three kinds of BN nanomaterials with low dimensions, we found that the zero-dimensional B12N12 nanocage broke the inherent reaction inertia of BN materials and showed good catalytic activity in an acetylene acetate reaction, which is very likely to be a non-metallic catalyst for the acetylene gas-phase preparation of vinyl acetate. 相似文献
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Xiansu Cheng Huaimin Guan Yingcao Su 《Journal of Inorganic and Organometallic Polymers》2000,10(3):115-126
A hydrophobic film of copper alginate coordination polymer was prepared by soaking a sodium alginate film in a 13% CuCl2 aqueous solution at room temperature for more than 24 h. The composition, structure, and property of copper alginate as a coordination catalyst were studied by ESR, IR, XPS, and electric conductivity methods. It was shown that a low-spin copper complex was formed as a result of the acceptance by dsp2 hybrid orbitals of nonpaired electrons transferred from oxygen atoms of two carbonyl hydroxyl groups and negatively charged oxygen atoms of two deprotonated carbonyl hydroxyl groups of two alginate chains. The coordination number of the central Cu2+ ions in copper alginate is 4. It can be concluded that the vacant site on the active catalysis resulted from the distorted tetragonal configuration that was caused by a crimped chain of the alginate molecule. HSO3– produced primary free-radical hydrogen by a coordination catalysis mechanism and vinyl acetate (VAc) polymerization by a free-radical mechanism that is different from polymerization initiated by a CuCl2–Na2SO3–H2O oxidation–reduction system. The induction period for VAc polymerization is 90 s and the yield is 82%. The Mw, Mn, and Mw/Mn of poly(vinyl acetate) (PVAc) were found to be 1.23×106, 2.27×105, and 4.51, respectively. 相似文献
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有机硅氧烷改性醋酸乙烯酯-丙烯酸酯乳液的合成与性能 总被引:7,自引:1,他引:6
采用种子乳液聚合,引入乙烯基三甲氧基硅烷(A-171),以十二烷基苯磺酸钠(DSB)和壬基酚聚氧乙烯(20)醚(OP-10)作复合乳化剂,以过硫酸钾(KPS)为引发剂,在反应温度为78±2℃条件下,合成了A-171改性醋酸乙烯酯(VAc)-丙烯酸酯共聚乳液。实验采用单体滴加工艺,考察了配方中丙烯酸丁酯(BA)、甲基丙烯酸(MAA)和A-171用量对共聚物性能和乳液聚合过程的影响,并用红外光谱仪(FTIR)、粒度仪和差示量热扫描仪(DSC)对共聚物的结构及性能进行了表征。结果表明,引入w(BA)=10%~15%(相对于配方中单体总质量,下同)、w(MAA)=4%、w(A-171)=1%到VAc-丙烯酸酯共聚物乳液中,共聚物乳液涂膜的吸水率<5.0%,耐寒性通过10个循环,60℃加速贮存稳定性>100 d。 相似文献