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邻羟基苯乙酮和对羟基苯乙酮的合成 总被引:4,自引:0,他引:4
邻和对羟基苯乙酮都是重要的有机合成原料。其合成可以通过 Fries 重排实现:在三氯化铝催化下,乙酸苯酯重排,同时生成邻羟基苯乙酮和对羟基苯乙酮。据文献报道:在硝基苯中,反应可在常温常压下反应,主要生成对羟基苯乙酮,但收率不高(32%),而文献也没报道邻羟基苯乙酮的收率。本文作者在实验中发现,改用氯苯做溶剂,在实验条件下不仅能得到高收率的对羟基苯乙酮,而且又能方便地分出邻羟基苯乙酮。两种产物的总收率可达92%。1 实验步骤1)乙酸苯酯:取苯酚188g,乙酐214g,混合 相似文献
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对羟基苯乙酮氨肟化制备对羟基苯乙酮肟 总被引:1,自引:0,他引:1
考察了在HTS-1分子筛催化剂上对羟基苯乙酮(简写为4-HAP)在固定床反应器中与氨和过氧化氢发生氨肟化反应合成对羟基苯乙酮肟(简写为4-HAPO)的反应规律,4-HAP氨肟化反应的适宜条件为:以乙醇为溶剂、温度高于60℃、反应时间大于5 h、4-HAP宜一次性加入、氨和过氧化氢连续加入、催化剂的质量分数为w(HTS-1)=1.4%、n(NH3)∶n(H2O2)∶n(4-HAP)=4.2∶1.1∶1、n(溶剂)∶n(4-HAP)=6∶1,4-HAP转化率达到73.9%,4-HAPO选择性达到98.9%,该结果优于类似条件下US 5 466 869报道的结果。通过色质联用分析鉴定了4-HAP氨肟化反应的产物,与现有的文献报道相比,HTS-1分子筛具有较高的活性和选择性,副产物的种类和数量均较少。4-HAP氨肟化反应过程中产生的副产物主要为1,8,9-蒽三酚(THA)和对苯二酚(HQ)。适当提高反应温度和催化剂浓度、提高氨与4-HAP的比例、控制过氧化氢与4-HAP在适当的摩尔比(如1.1∶1),可抑制这两种副产物的生成。HQ和1,8,9-蒽三酚在氨存在下发生氧化反应是反应产物颜色变深的原因。 相似文献
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报道了以3,5-于羟基甲酸为起始原料合成3,5-二羟基苯乙酮的方法,并讨论了其优惠工艺条件。该工艺流程短、成本低。总收率这41%,原药纯度达到98%,熔点114 ̄146℃。 相似文献
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本文以间苯二酚及其类似物C—乙酰化为代表,总结了酚类化合物 C—酰基化的方法,介绍了各类方法的新的进展。 相似文献
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以3-甲氧基苯甲醛为原料,经亨利反应、还原硝基和双键、氨基保护、傅-克酰基化、脱甲基、环合、羰基还原等反应,合成目的产物6-2-氨丙基-2,3-二氢苯并呋喃。并对硝基和双键的还原反应、傅-克酰基化和脱甲基反应的工艺条件进行了优化,得出较佳工艺条件:(1) 还原反应:反应温度40 ℃,氢气压力4.0 MPa,Raney-Ni质量为化合物2的质量的8 %,产物收率为78.6 %;(2)合成化合物6的较佳工艺条件:反应温度45 ℃,n(氯乙酰氯):n(化合物4)=1.4:1,反应时间为6 h,产物的收率为68.8 %。 相似文献
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酶催化选择性酯化在蔗糖酯合成中的应用研究进展 总被引:3,自引:0,他引:3
较详细地综述了近年来国外酶催化选择性合成蔗糖酯方面的研究成果,对反应使用酶的类型、酶源、反应介质等对产物酰化位置以及取代数目的影响进行了分析,认为蔗糖酰化使用酶的类型主要有蛋白酶和脂肪酶,反应使用的介质除了普通有机溶剂、无溶剂反应外,还有离子液体和超临界流体;当用蛋白酶酰化时,反应大多优先发生在C-1′位置,部分优先在C-2位置,用脂肪酶酰化时,一般优先酰化C-6位置,然后是C-6′和C-1′位置。指出了在离子液体、超临界流体中蔗糖选择性酰化的反应是未来值得研究的重要内容。 相似文献
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The synthesis of novel dihaloarenes (1,5-bis(4-halophenyl)-2,6-dimethylnaphthalenes, 1), polycondensation of 1 with biphenols, and properties of the obtained polymers were described. Selectively Friedel-Crafts acylation of 2,6-dimethylnaphthalene with 4-halobenzoyl chlorides in nitrobenzene afforded 1 in high yields. X-Ray single-crystal structural analysis of 1 supported that the dibenzoylation proceeded regioselectively at the 1- and 5-positions and the two methyl groups sterically inhibited the coplanarity of the aromatic planes. The polycondensation of 1a with Bisphenol A in toluene/N-methyl-2-pyrrolidone (NMP) mixed solvent in the presence of excess potassium carbonate as a condensation reagent was carried out at 180°C for several hours to quantitatively afford the corresponding poly(arylene-ether-ketone) (PEK) 3 with a high molecular weight (Mn −30,000) as a slightly yellow powder. To evaluate the effect of the methyl groups of 3, polycondensation of 2,6-bis(4-fluorobenzoyl)naphthalene 2 with Bisphenol A was carried out for comparison and the corresponding PEK 4 was obtained quantitatively. Whereas 3 was soluble in ordinary organic solvents such as tetrahydrofuran (THF) and chloroform at room temperature, 4 was insoluble in common solvents except for strong acids such as conc. sulfonic acid. 3 showed a high glass-transition temperature (238°C) and a 5% weight loss temperature of 457°C. The polycondensations of 1a with various biphenols such as dihydroxybenzophenone were carried out to examine the properties of the obtained polymers. The obtained PEKs showed high glass transition temperatures and 5% weight loss temperatures as well as good solubilities in ordinary organic solvents at room temperature. Casting of the polymers from THF solution gave transparent, tough, flexible, and amorphous films. 1,5-Bis(4-chlorobenzoyl)-2,6-dimethylnaphthalene 1b similarly underwent a polycondensation reaction with Bisphenol A to give the corresponding polymer quantitatively. 相似文献
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Michela Signoretto Antonella Torchiaro Anna Breda Francesco Pinna Giuseppina Cerrato Claudio Morterra 《Applied catalysis. B, Environmental》2008,84(3-4):363-371
A series of sulphated zirconia samples (SZ) promoted with Al2O3, Ga2O3, and Fe2O3 were synthesized by co-precipitation at constant pH and aged under reflux conditions. Structural, surface and catalytic properties of the samples were investigated using N2 adsorption/desorption, thermal analysis, in-situ FTIR spectroscopy, TPR–MS and EGA–MS measurements. The catalytic performance of promoted SZ in anisole acylation has been investigated. Promotion by either Fe2O3 or Ga2O3 was found to increase the catalytic activity (yield) after recycle of catalysts with respect un-promoted sample, whereas promotion by Al2O3 was observed to increase the conversion but not the yield. It is worth noting that all systems present high selectivity to the p-metoxyacetophenone product. 相似文献