沸石催化的2,4,4-三甲基-1-戊烯的酰化反应

通过HY沸石与某些传统催化剂的比较，发现HY在2，4，4-三甲基-1-戊烯与乙酸酐的酰化反应中比那些传统催化剂更有效．用HY沸石作催化剂，室温下通过2，4，4-三甲基-1-戊烯与乙酸酐的酰化反应，合成了三种异构体，即4-（2，2-二甲基丙基）-4-戊烯-2-酮、（E）-4，6，6-三甲基-4-庚烯-2-酮和（Z）-4，6，6-三甲基-4-庚烯-2-酮．考察了HY沸石的用量对该酰化反应的影响．当2，4，4-三甲基-1-戊烯／乙酸酐／HY沸石=1mmol／10mmol／0．250g，反应温度25℃、反应时间2h时，生成的三种异构体产率之和为72％，HY沸石对于该反应具有极好的选择性和优良的活性稳定性，不同阳离子交换的Y沸石也用于催化2，4，4-三甲基-1-戊烯的酰化反应。     

用新方法催化合成6-乙酰基-1-甲基环己烯

室温下用HY沸石取代传统催化剂通过1-甲基环己烯与乙酐的酰基化反应合成了6-乙酰基-1-甲基环己烯，考察了HY沸石的SiO2／Al2O2摩尔比、用量和活化时间以及反应时间对该酰化反应的影响．当1-甲基环己烯／乙酐／HY沸石(SiO2／Al2O3摩尔比=29)=1mmol／10mmol／0．200g、反应温度25℃、反应时间3h时，所得酰化产品的产率为60％，HY沸石能够回收和重新使用，显示出与新鲜催化剂几乎相同的催化活性．     

Hβ分子筛催化的甲苯与乙酸酐(AA)酰化反应研究

以Hβ分子筛为催化剂，对甲苯与乙酸酐(AA)的酰化反应进行了研究。通过研究反应温度、压力、甲苯与乙酸酐(AA)摩尔比、催化剂用量、以及溶剂的种类和用量等因素对反应转化率和选择性的影响，确定了较优的反应条件。结果表明，Hβ分子筛对甲苯与乙酸酐(AA)酰化反应具有较好的催化活性和选择性，适宜的反应条件为：温度130 ℃、甲苯/乙酸酐(AA)摩尔比20、催化剂/乙酸酐(AA)重量比0.8，极性溶剂如硝基苯等对酰化反应有一定的促进作用，但选择性有所下将，而非极性溶剂如二氧化碳可部分抑制催化剂的失活。     

苯甲醚在复合催化剂上的催化酰化

复合催化剂首次用于催化苯甲醚与酰化剂乙酰氯的酰化反应.发现不同沸石的单独使用仅给出很低产率的对-甲氧基苯乙酮.但是由HY沸石(硅铝比=40)或USY(超稳Y沸石)和SnO组成的复合催化剂的催化活性比单独使用沸石时高得多.增加由USY沸石和不同量的SnO组成的复合催化剂中的SnO的量,导致对-甲氧基苯乙酮产率的提高.由H型沸石(HY和H-ZSM-5沸石)和SnO组成的复合催化剂在苯甲醚与乙酰氯的酰化反应中的催化活性主要取决于所用沸石的硅铝比.     

磷钨酸铝催化合成对甲氧基苯乙酮

以H3PW12O40和AlCl3·6H2O为原料合成AlPW12O40,以此为催化剂研究苯甲醚与乙酸酐的酰基化反应,其主要产物为对甲氧基苯乙酮.采用正交试验确定酰化反应的适宜条件为:苯甲醚0.1 mol,苯甲醚与乙酸酐物质的量比为1∶1.5,催化剂用量1 g,反应时间4h,反应温度100℃,在此条件下,产品收率达到69.80％.考察了不同反应底物及不同酰化试剂对反应的影响和不同磷钨酸盐的催化效果,比较了不同加热方式对催化反应的影响.结果表明,磷钨酸铝的催化活性最好,微波加热合成目标产物效果更好.     

乙酸苄酯在H-β沸石上的催化合成

β沸石是一种高硅大孔沸石^[1],H－β沸石已用于催化某些有机反应,例如芳醚的酰化^[2],歧化反应^[3]等。酯化反应通常用浓硫酸或Lewis酸作催化剂,但传统的方法有催化剂易流失,反应产物难纯制,腐蚀性和有毒废物等缺点,用HZSM－5等固体酸催化剂^[4,5]能显克服这些,本报道用H－β沸石作催化剂合成乙酸苄酯的结果。     

在氯化亚锡存在下2,3-二甲基-2-丁烯与乙酐的催化酰化反应

一种新的催化剂,SnCl2·2H2O,已用于2,3-二甲基-2-丁烯与乙酐的酰化反应来制备高产率的3,3,4-三甲基-4-戊烯-2-酮 (TMP). 发现SnCl2·2H2O是室温下2,3-二甲基-2-丁烯与乙酐进行酰化反应的有效催化剂. 考察了催化剂用量、乙酐用量、反应时间和溶剂的加入等因素对该酰化反应的影响. 发现当催化剂/2,3-二甲基-2-丁烯摩尔比在0.30/1和 0.60/1之间、反应时间为2 h时,所得酰化产品的产率最高. 该酰化反应进行到完全所需的时间取决于催化剂用量和乙酐用量. 在需要加入溶剂的情况下,二氯甲烷或氯仿是一种合适的溶剂.     

纤维素在离子液体中的均相乙酰化及其选择性

在1-烯丙基-3-甲基咪唑氯盐(AMIMCl)离子液体中进行了纤维素的均相乙酰化. 酯化剂为乙酸酐和乙酰氯以及加入或不加入催化剂吡啶. 用滴定法确定了产物的取代度(DS), 根据¹³C NMR考察了产物的取代度分布. 结果表明: 酰氯酰化的反应速度比酸酐快; 吡啶能加快乙酸酐的酯化反应, 但减慢酰氯的反应; 使用乙酸酐/吡啶酯化时所得产物具有特殊的取代度分布, 即DS_C-2>> DS _C-3.     

用高浓度杂多酸溶液催化苯甲醚与乙酸酐的酰化反应

芳香化合物经Friedel-Crafts酰化反应制备药物和香料中间体芳香酮是近年来人们感兴趣的课题^[1-4]。用于该反应的传统催化剂是Lewis酸金属氯化物。由于反应过程中催化剂可与酰化试剂羧基产物形成配合物,因而催化剂用量大,且所形成的配合物水解后产生大量废液。为了减少环境污染,人们已成功地用分子筛催化剂代替传统催化剂催化芳香化合物的酰化反应^[5-7]。其中包括用分子筛催化各种芳香化合物与乙酸酐的酰化反应^[8]。我们已经研究了用杂多酸－乙酸浓溶液催化异丁烷与丁烯的烷基化反应^[9,10],以及烯烃与羧酸的直接酯化反应^[11]。本文将报道杂多酸－乙酸浓溶液对苯甲醚与乙酸酐酰化反应的催化活性。     

在H3PO4存在下2,3-二甲基-2-丁烯与乙酐的酰化反应

在H3PO4存在下进行了2，3－二甲基－2－丁烯与乙酐的酰化反应，结果表明，H3PO4是室温下催化2，3－二甲基－2－丁烯与乙酐酰化反应的有效催化剂，在H3PO4存在下，酰化产物的收率主要取决于：（a)H3PO4的用量，（b)乙酐的用量；（c)反应温度和（d)反应时间，在适宜反应条件下，所得3，3，4－三甲基－4－戊烯－2－酮（TMP）约为99％，另外还发现，反应体系中加入少量乙酸，不会明显减少酰化产物的收率，乙酐的纯度，反应物的加入顺序对该反应几乎没有任何影响，在有和没有溶剂CH2Cl2的条件下所得酰化产物的收率是可比的。     

Catalytic Acylation of Ethylidenecyclohexane over Zeolite Catalysts

Beak et al[1 ] reported that the acylation of ethylidenecyclohexane( EDC) using zincchloride as a catalyst gave 3 -( 1 -cyclohexenyl) -2 -butanone( CHB) in good yield.However,it is pity that they provided only little information about reaction conditions,and no information on comparison of activities of various catalysts. Itis well known thatconventional Zn Cl2 catalyst leads to a great number of environmental pollution,whichcould be mainly overcome by use of the solid catalysts as we have …     

Synthesis of 3-(1-Cyclohexenyl)-2-butanone via Environmentally Friendly Catalysts

Introduction3- ( 1 - Cyclohexenyl) - 2 - butanone( CHB) is oneofthe importantchemicals and has a potential valuein perfume industry.Beak et al.[1] reported thatthe acylation of ethylidenecyclohexane( EDC) withzinc chloride as a catalystgave3- ( 1 - cyclohexenyl) -2 - butanone in a good yield,butthey have notmadea more detailed investigation.The use of such aconventional catalyst as zinc chloride leads to anumber of problems such as corrosion,unclean re-action products and the disposal of pot…     

Friedel-crafts acylation of 2-methoxynaphthalene over h-beta catalysts: effect of Si/Al ratio

The acylation of 2-methoxynaphthalene with acetic anhydride was carried out over zeolite beta catalysts having various Si/Al ratios. It was found that the reaction performance is strongly dependent on the Si/Al ratio of the catalyst. The catalytic reaction features were elucidated in terms of the acidic properties of the catalysts. This revised version was published online in June 2006 with corrections to the Cover Date.     

Further studies on the reaction of N-(2-Hydroxyphenyl)anthranilic acids with acetic anhydride

Reaction of N-(2-hydroxyphenyi)anthranilic acids (I) with acetic anhydride was investigated further. Treatment of Ia with refluxing acetic anhydride for 3 hours afforded two minor products, IIIa and IV, in addition to the previously reported IIa. Under similar conditions, the reaction of Ib with acetic anhydride afforded IIb as reported previously, and IIIb and IXb in small quantities. Treatment of IIIb with hydrazine gave X, and treatment of IXb with methoxyethylamine gave XI. When Ic was allowed to react with refluxing acetic anhydride, there were obtained three minor products, IIIc, IXc and XIII, in addition to IIc. Reaction of Id with acetic anhydride gave IId, and two minor products IXc and XIV. The formation of these minor products in the reaction of Ia-d with acetic anhydride are discussed based on the reation mechanism proposed previously for the formation of II.     

Catalytic Acylation of Anisole over Some Zeolites

Introduction　　 Friedel- Crafts acylation is one of the most important methods for synthesizing aromaticketones[1 ].Lewis acids or other catalysts are used in order to allow the reaction of anisole toproceed ata convenientrate.Forexample,the reaction of anisole with aceticanhydride in thepresence of aluminium chloride(Al Cl3/ anisole molar ratio=2 .2 / 1 ) gives4- methoxyace-tophenone in a good yield[2 ].Polyphosphoric acid(PPA/ anisole molarratio=1 3.6 / 1 ) hasalsobeen used for the react…     

Effects of acyl donor type, catalyst type, and reaction conditions on the activity and selectivity of Friedel-Crafts acylation

Acylation of anisole and 3-methylanisole was performed with several acylating reagents (acetylation by AcCl and Ac₂O and bromoacetylation by BrAcCl and (BrAc)₂O) over different solid acid catalysts. The reaction conditions were optimized with respect to the acylation reagent, overall yield, solid acid catalyst, and the products selectivities. While acylation of anisole with acetyl chloride or acetic anhydride resulted in its full conversion to para-substituted acetophenone, the use of bromoacetyl bromide or bromoacetic anhydride yielded also the ortho-substituted product. Acylation of 3-methylanisole also yielded both para- and ortho-substitutions, and the products distribution was affected by the reaction conditions and catalyst type. It was found that while more acidic catalysts (caesium salt of heteropolyacid and zeolites) were the most active towards anisole acylation, the most active catalysts for the acylation of 3-methylanisole were ion-exchange catalysts. Employing HY-740 zeolite resulted in the highest ortho-selectivity in the acylation of anisole with bromoacetyl bromide and bromoacetic anhydride and in the acylation of 3-methylanisole with acetic anhydride.     

M-Na-P-Mo-V/SiO2系列催化剂对异丁烯氧化反应的催化性能

 以浸渍法制备了M－Na－P－Mo－V／SiO2系列催化剂,并用FT－IR和TPR对催化剂进行了表征,考察了催化剂上的异丁烯化反应．结果表明,在空速900h－1和345℃的反应条件下,过渡金属的引入可提高甲基丙烯醛的选择性．其中Cu对催化性能的改善最佳,甲基丙烯醛选择性可达65．7％;而在Na－P－Mo－V／SiO2催化剂上,乙酸选择性可达50％,但甲基丙烯醛选性仅为4．1％．在催化剂中引入过渡金属时,Cu在提高甲基丙烯醛选择性的同时,也抑制了完全氧化产物COx的生成;Fe提高双键断裂产物和完全氧化产物选择性的同时,使甲基丙烯醛选择性下降;Zn对反应的影响不很大．TPR结果表明,在入Cu的催化剂中,Cu与杂多酸阴离子之间可能存在“溢流”作用．     

金属化合物催化的1,1′-联二萘酚-4,4′-二乙酸酯和二(2-乙基己醇)碳酸酯的酯交换

芳香族聚碳酸酯性能优良,其中双酚-A型聚碳酸酯是应用广泛的工程塑料,通常采用光气法或酯交换法来制备,但芳香双羟基化合物与二烷基碳酸酯的酯交换反应速度十分缓慢,需要使用催化剂,且反应温度较高,反应过程伴随着复杂的副反应。本文用金属化合物作催化剂进行1,1′-联二萘酚-4,4′-二乙酸酯和二(2-乙基己醇)碳酸酯的酯交换反应,评价了不同金