共查询到19条相似文献,搜索用时 161 毫秒
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磷钨酸镧催化合成缩醛(酮)的研究 总被引:2,自引:0,他引:2
以磷钨酸镧为催化剂催化合成了苯甲醛乙二醇缩醛、苯甲醛1,2-丙二醇缩醛及环己酮乙二醇缩酮.较系统研究了反应物料配比、催化剂用量、反应时间、催化剂重复使用性能等因素对反应的影响.结果表明:在醛(酮)/二元醇(乙二醇、1,2-丙二醇)=1.0:1.5(mol/mol),催化剂用量为反应物料总质量的1.0%,环己烷为带水剂,在反应温度86~96℃条件下,反应时间2.0h,苯甲醛乙二醇缩醛收率为78.5%,苯甲醛1,2-丙二醇缩醛收率为76.1%,环己酮乙二醇缩酮收率为79.5%. 相似文献
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通过对双齿膦配体的单P原子定向甲基化,合成了两种离子型"叔膦-季鏻鎓Lewis酸"双功能配体L2和L3,该类双功能配体分子结构中既含有与过渡金属配位的叔膦基团,又含有具Lewis酸的季鏻鎓基团.研究结果表明,在合成气的体积比(CO/H2)为4∶1时,双功能配体L2修饰的[Ir(COD)Cl]2催化剂高效催化烯烃的"氢甲酰化-缩醛化"串联反应,1-辛烯的转化率为98%,缩醛的选择性高达86%,其催化活性好于同等条件下的Rh催化剂.双功能配体L2与[Ir(COD)Cl]2原位构建的共催化体系的催化效果远优于Ir(I)配合物和季鏻鎓Lewis酸的物理混合;同时还表现出较好的底物普适性.此外,由于双功能配体L2的高极性,其修饰的Ir催化剂可以顺利实现与正己烷溶液的分离,从而实现催化剂的回收循环使用. 相似文献
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在220℃和50-60大气压条件下,利用固定床对NiO/SiO2、NiO/Al2O3、NiO-La2O3/Al2O3和NiO-Bi2O3/Al2O3催化剂上的乙炔与甲酸甲酯加氢酯化合成丙烯酸甲酯进行了研究。镍基催化剂对乙炔的加氢酯化合成丙烯酸甲酯具有很好的活性。用浸透法制备的Mo/SiO2催化剂的活性和丙烯酸甲酯的选择性均比离子交换法差。NiO/Al2O3催化剂用La或Bi改性后,其催化活性大大提高。XPS、XRD和TPR结果表明,当催化剂用La或Bi改性后,NiO的晶粒明显减小,催化剂表面的Ni/Al原子比增大,催化剂的第二个还原峰温大大降低。 相似文献
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均相催化剂的固载化和以高分子材料作为催化剂载体的研究及开发,近年来受到人们的的重视。Neckers和Sket等曾将极易水解的AlCl_3和BF_3分别与聚苯乙烯反应制成高分子载体催化剂,应用于缩醛、缩酮、酯化等反应,具有良好的催化效能。本文将在空气中极易水解的Lewis酸四氯化钛与苯乙烯和甲基丙烯酸甲酯的共聚物小球反应,制成了一种十分稳定的高分子载体Lewis酸催化剂,证明它对酯化、缩醛、缩酮等反应有较高的催化活性,并可重复使用、回收再生。由于它制备简单、操作方便、易于从反应体系中分离、无污染,因此具有良好的应用前景。 相似文献
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以香兰素和1,2-丙二醇为原料,以介孔分子筛MCM-41负载磷钨酸为催化剂,环己烷为带水剂,合成了香兰素1,2-丙二醇缩醛.考察了醛醇物质的量比、反应时间、带水剂用量、催化剂用量及负载量对产率的影响.实验表明,介孔分子筛MCM-41负载磷钨酸是合成香兰素1,2-丙二醇缩醛的理想催化剂,较优反应条件为:n(香兰素)∶n(1,2-丙二醇)=1∶2.4,负载量为50%,催化剂用量为反应物总质量的2.0%,带水剂环己烷15mL,回流反应2.0h,香兰素1,2-丙二醇缩醛的收率达92%以上. 相似文献
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采用溶剂蒸发法制备了Cu3(BTC)2质量分数为60%的Cu3(BTC)2@PS复合基质膜, 并对其形貌和结构进行了表征. 结果显示, Cu3(BTC)2 均匀分布于复合基质膜中且具有较好的热稳定性. 以醇醛缩醛化反应为探针反应, 测试了复合基质膜的催化性能, 结果表明, 在该膜催化下苯甲醛的转化率高达99%, 苯甲醛二乙缩醛的选择性为99%. 此类催化膜具有良好的实用性, 能实现连续24 h高效率生产苯甲醛二乙缩醛, 可将其应用于工业上的连续化生产. 相似文献
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N. Nugay T. Nugay R. Jrme Ph. Teyssi 《Journal of polymer science. Part A, Polymer chemistry》1997,35(8):1543-1548
Poly(methyl methacrylate-b-n-butyl acrylate) (PMMA-b-Pn-BuA) and poly(methyl methacrylate-b-n-nonyl acrylate) (PMMA-b-Pn-NonA) diblock copolymers have been successfully synthesized by the sequential anionic polymerization of methyl methacrylate (MMA) and the n-alkyl acrylate (n-BuA or n-NonA), in a 90/10 toluene/tetrahydrofuran (THF) mixture at −78°C. When diphenylmethyllithium (DPMLi) ligated with lithium 2-(2-methoxyethoxy) ethoxide (LiOEEM) is used as the initiator, the polymerization of each block appears to be living. Molecular weight and composition of block copolymers can be predicted from the monomer over initator molar ratio and the molecular weight distribution is narrow. Size exclusion chromatography (SEC) supports that no homo-PMMA contaminates the final copolymer. Although the reverse polymerization sequence Pn-NonA-b-PMMA always results in some contamination by homo-Pn-NonA, it has no really significant effect on the final product characteristics. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1543–1548, 1997 相似文献
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溶胶-凝胶法制备丙烯酸甲酯-衣康酸酐共聚物/SiO_2杂化材料 总被引:2,自引:0,他引:2
以丙烯酸甲酯( MA) 和衣康酸酐(Itn) 的无规共聚物和原硅酸四乙酯(TEOS) 作为有机相与无机相前驱体,以3 氨丙基三乙氧基硅烷(APTES) 为偶联剂,通过溶胶 凝胶过程制备出有机 无机杂化材料.并通过SEM、DSC 等方法考查了偶联剂用量对所得材料结构及性能的影响. 相似文献
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淀粉与丙烯酸甲酯的接枝共聚物作为生物降解塑料的研究 总被引:6,自引:0,他引:6
如何解决废弃塑料制品的再资源化和使用无污染的降解塑料是当今人类急待解决的热点课题.淀粉与丙烯酸甲酯(MA)进行接技共聚以制备塑料发泡产品的研究已有报道[‘-‘1,一般认为塑料中淀粉含量在40%以上的产品,很容易在土壤中被微生物降解掉[‘].这些研究都是在水溶液体系中进行的,本文的目的在于开发高淀粉含量的接校共聚物,为此对比了在3种不同体系(MA-CH3OHA12O三元均相溶液体系,水溶液体系和乳液体系)中得到的接校共聚物的力学性能、形态观察与组成情况,发现单纯追求高接技效率与接枝链MA的高分子量并不一定能得到… 相似文献
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长余辉光致发光聚甲基丙烯酸酯共聚物球粒的合成 总被引:3,自引:0,他引:3
过去仅用ZnS和CaS等的长余辉发光材料(发光时间只有十几分钟 )。加入少量Co、Pm物质 ,发光时间延长 ,亮度提高 ,但Co、Pm具有放射性。以铝酸盐为基料制备的发光材料发光时间 ,发光强度明显提高。铝酸盐掺杂少量稀土元素Dy、Eu ,制得发绿光的高亮度光致发光材料、余辉时间长达 1 5h以上 ,而且该材料的使用寿命长 ,高达 1 0年以上[1 ] 。本文研制的发光球粒以甲基丙烯酸甲酯和丙烯酸乙酯为单体 ,少量的发光粉为关键组份 ,采用悬浮聚合方法合成得到。聚甲基丙烯酸甲酯(PMMA)具有优良的透明度、光泽度和强度 ,而且具有良… 相似文献
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K. B. Wiles V. A. Bhanu A. J. Pasquale T. E. Long J. E. McGrath 《Journal of polymer science. Part A, Polymer chemistry》2004,42(12):2994-3001
Nonlinear monomer reactivity ratios for the homogeneous free‐radical copolymerization of acrylonitrile and methyl acrylate were determined from 1H NMR and real‐time Fourier transform infrared (FTIR) analyses. All 1H NMR data were obtained on polymers isolated at low conversions (<10%), whereas the FTIR data were collected in situ. The copolymerizations were conducted in N,N‐dimethylformamide at 62 °C and were initiated with azobisisobutyronitrile. The real‐time FTIR technique allowed for many data points to be collected for each feed composition, which enabled the calculation of copolymer compositions (dM1/dM2) with better accuracy. Monomer reactivity ratios were estimated with the Mayo–Lewis method and then were refined via a nonlinear least‐squares analysis first suggested by Mortimer and Tidwell. Thus, monomer reactivity ratios at the 95% confidence level were determined to be 1.29 ± 0.2 and 0.96 ± 0.2 for acrylonitrile and methyl acrylate, respectively, which were valid under the specific system conditions (i.e., solvent and temperature) studied. The results are useful for the development of acrylonitrile (<90%) and methyl acrylate, melt‐processable copolymer fibers and films, including precursors for carbon fibers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2994–3001, 2004 相似文献
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以二乙醇胺和丙烯酸甲酯为原料,在甲醇中经Michael加成反应合成中间体N,N-二羟乙基-3-胺基丙酸甲酯(TAD-0.5G); TAD-0.5G与乙二胺经酰胺化缩合反应合成N,N-二羟乙基-N′-乙胺-3-胺基丙酰胺(TAD-1.0G),其结构经IR, MS(ESI)和元素分析确证。并优化了TAD-1.0G的合成条件。结果表明:在最佳合成条件[TAD-0.5G 0.11 mol, n(TAD-0.5G) :n(乙二胺)=1.6 :1.0,于35 ℃反应24 h]下,产率91.62%。采用MS(ESI)研究了TAD-1.0G分子裂解后的主要离子碎片和裂解途径。 相似文献
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A series of polyacrylate‐polystyrene‐polyisobutylene‐polystyrene‐polyacrylate (X‐PS‐PIB‐PS‐X) pentablock terpolymers (X=poly(methyl acrylate) (PMA), poly(butyl acrylate) (PBA), or poly(methyl methacrylate) (PMMA)) was prepared from poly (styrene‐b‐isobutylene‐b‐styrene) (PS‐PIB‐PS) block copolymers (BCPs) using either a Cu(I)Cl/1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) or Cu(I)Cl/tris[2‐(dimethylamino)ethyl]amine (Me6TREN) catalyst system. The PS‐PIB‐PS BCPs were prepared by quasiliving carbocationic polymerization of isobutylene using a difunctional initiator, followed by the sequential addition of styrene, and were used as macroinitiators for the atom transfer radical polymerization (ATRP) of methyl acrylate (MA), n‐butyl acrylate (BA), or methyl methacrylate (MMA). The ATRP of MA and BA proceeded in a controlled fashion using either a Cu(I)Cl/PMDETA or Cu(I)Cl/Me6TREN catalyst system, as evidenced by a linear increase in molecular weight with conversion and low PDIs. The polymerization of MMA was less controlled. 1H‐NMR spectroscopy was used to elucidate pentablock copolymer structure and composition. The thermal stabilities of the pentablock copolymers were slightly less than the PS‐PIB‐PS macroinitiators due to the presence of polyacrylate or polymethacrylate outer block segments. DSC analysis of the pentablock copolymers showed a plurality of glass transition temperatures, indicating a phase separated material. 相似文献
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用气相色谱法分离提纯食用香料甲基 2 甲基 3 呋喃基二硫醚 ,纯度 (质量分数 )达到 99.5%。分离柱为4%FFAP +1 %H3PO4ChromosorbW /AW DMCS(80目~ 1 0 0目 )不锈钢柱。用红外光谱、气相色谱 /质谱和核磁共振谱进行了结构鉴定。 相似文献
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Sebla Onbulak Yanzhao Wang Jacob P. Brutman Marc A. Hillmyer 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):3117-3126
One new and one established functional cyclooctene were prepared and (co)polymerized using ring-opening metathesis polymerization. The resulting polymers were hydrogenated to yield the corresponding functional polyolefins that were structurally equivalent to copolymers of ethylene and either methyl methacrylate, t-butyl acrylate, or acrylic acid after deprotection. The copolymers that incorporate methyl methacrylate into the backbone were used as compatibilizers for poly(methyl methacrylate)/polyethylene blends. The copolymers that incorporate t-butyl acrylate into the backbone yielded elastomers that could be thermally crosslinked. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3117–3126 相似文献