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…     

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．     

三聚异丁烯的催化酰化

室温下FeCl3用于催化三聚异丁烯(TIB)与乙酸酐的酰化反应.发现FeCl3在所研究的催化剂中是最有效的.考察了FeCl3的用量、乙酸酐的用量和反应时间等因素对该酰化反应的影响.该反应产生一种混合物,其中两种产物是主要的.当反应在1 mmol TIB/15 mmol乙酸酐/0.50 mmol FeCl3/0.43 g氯仿和25℃下进行2 h时,生成的两种主要产物的总产率为69%.另外,反应在由沸石和FeCl3或P2O5组成的共催化剂存在下进行.该反应也用HY和H-β沸石之类的多相催化剂进行了尝试.负载FeCl3的HY和H-β沸石催化剂比FeCl3具有更高的催化活性和选择性.     

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.     

Highly active and reusable heterogeneous catalysts for acylation of anisole

In the present study, non-conventional solid acid catalysts such as NaY, metal ion exchanged zeolite NaY (Zn²⁺, Fe³⁺, Ce³⁺, La³⁺ and Nd³⁺), H-mordenite, H-β and HZSM-5 were used in order to overcome the disadvantages of conventional Friedel-Crafts catalysts for the acylation of anisole with acetic anhydride. Among the various zeolites studied, the HY zeolite shows an intermediate activity. Zeolite containing transition metal ions (Zn²⁺ and Fe³⁺) are less active and zeolite NaY is nearly inactive. The catalysts exhibit the activity in the order H-β>transition metal ions (Zn²⁺ and Fe³⁺)>HY>NaY zeolite. The highest catalytic activity of H-β could be due to its larger pore size. The type of acidity and the acid strength in zeolite Y were determined by FTIR and differential scanning calorimetric (DSC) studies on the pyridine adsorbed catalysts. The correlation of catalytic activity with acidity reveals that Brönsted acid sites in zeolite promote the acylation of anisole.     

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…     

2,3-二甲基-2-丁烯酰化合成3,3,4-三甲基-4-戊烯-2-酮的负载ZnCl2固体催化剂

研究了负载ZnCl2的固体催化剂在2，3-二甲基-2-丁烯与乙酐酰化合成3，3，4-三甲基-4-戊烯-2-酮反应中的催化活性。结果表明，K10粘土是最好的载体，但是HY沸石、Synclyst S13(一种无定型的酸性固体)、硅胶和氧化铝也都是制备负载ZnCl2的固体催化剂的有效载体。ZnCl2的负载量和改性方法都影响负载ZnCl2的固体催化剂的催化活性。     

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.     

Acylation of Anisole Catalyzed by Hierarchical Porous Hβ Zeolite Modified with Cr

Modified hierarchical porous Hβ zeolite was obtained by metal modification of Hβ zeolite, which was treated with alkaline solution, and the catalysts before and after modification were characterized by means of X-ray diffraction(XRD), nitrogen adsorption-desorption, scanning electron microscopy(SEM), X-ray fluorescence(XRF), NH₃ temperature-programmed desorption and Fourier-transform infrared spectroscopy(FTIR). The activities of acylation of anisole with acetic anhydride were also investigated. The results show that the Hβ zeolite, which was treated with alkaline solution has microporous and mesoporous structures that could improve the diffusion performance of chemical reaction. The amount of acid was modulated with metal modification. The Hβ zeolite modified by 5%(mass fraction) metal chromium had the best catalytic performance. The conversion of acetic anhydride acylation was 93.01% under the optimal conditions, which was higher than that of other catalysts. The catalyst not only showed good activity, but also exhibited a stable performance in regeneration tests.     

Friedel–Crafts acylation of pyrrole over ultrasonic-assisted phosphoric acid-modified Hβ zeolite

Friedel?CCrafts acylation of pyrrole with acetic anhydride was studied over different zeolites and an ultrasonic-assisted phosphoric acid-modified H?? (P-H??-US) zeolite was found to have the best catalytic performance among all the zeolites examined. The conversion of acetic anhydride reached 98.8% and the selectivity to acetylpyrroles was 97.0% under the optimized conditions. The high activity of the P-H??-US zeolite is attributed to the increase of weak acid sites, caused by the synergistic effect between the phosphoric acid modification and ultrasound. Moreover, the carbonaceous deposits, mainly due to the adsorption of reactants and products, on the surface acid sites and the blockage of the pores is believed to be the reason for the deactivation of the reused P-H??-US zeolite, confirmed from the Brunauer?CEmmett?CTeller (BET) method, scanning electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the catalyst activity can be recovered effectively by a subsequent calcination.     

在负载H3PO4的固体上3,3,4-三甲基-4-戊烯-2-酮的催化合成

3,3,4-Trimethyl-4-penten-2-one has been synthesized by the acylation of 2,3-dimethyl-2-butene with acetic anhydride in the presence of soild-supported H3PO4.By comparison of the acylation reactions of 2,3-dimethyl-2-butene with acetic anhydride over various soilds-supported H3PO4,it was found that K10 clay,silicagel,HY zeolite and HMordenite were good supports.The results obtined indicate that the soild-supported small amounts of H3PO4 possessed higher catalytic activities,For obatining a higher yield of 3,3,4-trimethyl-4-penten-2-one different supports required different modification methods.     

Selective methane chlorination to methyl chloride by zeolite Y-based catalysts

The CH₄ chlorination over Y zeolites was investigated to produce CH₃Cl in a high yield. Three different catalytic systems based on Y zeolite were tested for enhancement of CH₄ conversion and CH₃Cl selectivity: (i) HY zeolites in H⁺-form having various Si/Al ratios, (ii) Pt/HY zeolites supporting Pt metal nanoparticles, (iii) Pt/NaY zeolites in Na⁺-form supporting Pt metal nanoparticles. The reaction was carried out using the gas mixture of CH₄ and Cl₂ with the respective flow rates of 15 and 10 mL min⁻¹ at 300–350 °C using a fixed-bed reactor under a continuous gas flow condition (gas hourly space velocity = 3000 mL g⁻¹ h⁻¹). Above the reaction temperature of 300 °C, the CH₄ chlorination is spontaneous even in the absence of catalyst, achieving 23.6% of CH₄ conversion with 73.4% of CH₃Cl selectivity. Under sufficient supplement of thermal energy, Cl₂ molecules can be dissociated to two chlorine radicals, which triggered the C-H bond activation of CH₄ molecule and thereby various chlorinated methane products (i.e., CH₃Cl, CH₂Cl₂, CHCl₃, CCl₄) could be produced. When the catalysts were used under the same reaction condition, enhancement in the CH₄ conversion was observed. The Pt-free HY zeolite series with varied Si/Al ratios gave around 27% of CH₄ conversion, but there was a slight decrease in CH₃Cl selectivity with about 64%. Despite the difference in acidity of HY zeolites having different Si/Al ratios, no prominent effect of the Si/Al ratios on the catalytic performance was observed. This suggests that the catalytic contribution of HY zeolites under the present reaction condition is not strong enough to overcome the spontaneous CH₄ chlorination. When the Pt/HY zeolite catalysts were used, the CH₄ conversion reached further up to 30% but the CH₃Cl selectivity decreased to 60%. Such an enhancement of CH₄ conversion could be attributed to the strong catalytic activity of HY and Pt/HY zeolite catalysts. However, both catalysts induced the radical cleavage of Cl₂ more favorably, which ultimately decreased the CH₃Cl selectivity. Such trade-off relationship between CH₄ conversion and CH₃Cl selectivity can be slightly broken by using Pt/NaY zeolite catalyst that is known to possess Frustrated Lewis Pairs (FLP) that are very useful for ionic cleavage of H₂ to H⁺ and H⁻. Similarly, in the present work, Pt/NaY(FLP) catalysts enhanced the CH₄ conversion while keeping the CH₃Cl selectivity as compared to the Pt/HY zeolite catalysts.     

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.     

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.     

Fe-Zn-Zr/分子筛复合催化剂上CO2加氢合成异构烷烃Ⅰ.不同分子筛对催化剂性能的影响

 在Fe-Zn-Zr/分子筛复合催化剂上考察了不同类型的分子筛对CO2加氢反应性能的影响. 结果表明,不同分子筛对复合催化剂性能的影响不同,Fe-Zn-Zr/HY是合成异构烷烃有效的复合催化剂. 分子筛的酸性及酸强度对复合催化剂性能有较大的影响,中等强度和较高强度的酸性位有利于异构烃的生成.     

Synthesis of adamantane on zeolite catalysts

The synthesis of adamantane from tetrahydrodicyclopentadiene on zeolites with different framework structures was studied. The adamantane yield on HY zeolites is higher than on HM and HZSM-5 zeolites. Among various types of dealuminated HY zeolites the HEY and HUSY zeolites give higher adamantane yields than conventional HY zeolite. The changes in activity and selectivity of the main and side reactions are correlated with the acidity and the pore structure of the zeolites. To ion-exchange the HY and HUSY zeolites with Ni2+ and La3+ cations may further improve the activity and selectivity of the zeolite catalysts.     

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。     

High pressure nitration of toluene using nitrogen dioxide on zeolite catalysts

Nitration of toluene by nitrogen dioxide in the presence of zeolite catalysts was carried out in a high pressure reaction system. Different zeolites (viz. H-ZSM-5, H-mordenite, HY etc.) were used as catalysts. The effects of NO₂/toluene molar ratio and the total pressure on the formation of mono- and di-nitrotoluenes were also investigated. The N₂-sorption capacity, X-ray diffraction analysis and catalytic activity measurements of the regenerated HY catalyst revealed that the HY catalyst can be reused.