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2,2,6,6-四甲基-N-氧自由基哌啶醇(2,2,6,6-tetramethyl-piperidin-4-ol-N-oxyl,TEMPO)与氯乙酰氯反应生成2-氯乙酸-2,2,6,6-四甲基-1-氧-4-哌啶醇酯,该酯与N-甲基咪唑发生季铵化反应后再与六氟磷酸钾进行离子交换制得2,2,6,6-四甲基-N-氧自由基哌啶醇负载离子液体TEMPO-IL。温和条件下以离子液体1-甲基-3-丁基咪唑六氟磷酸盐(1-butyl-3-methylimidazolium hexafluorophosphate,[bmim]PF6)为溶剂,TEMPO-IL和CuCl为催化剂,分子氧氧化各种醇为相应的醛或酮。研究发现,该氧化体系对苄醇和烯丙醇有较好的氧化效果,65℃下反应10h左右,转化率可达99%,收率可达80%~90%。氧化体系对醛酮有高度的选择性,在实验所采用的条件范围内未检测到有羧酸生成。溶剂和催化剂可循环使用,在苯甲醇的氧化中,溶剂和催化剂循环使用6次,反应转化率和苯甲醛的收率保持不变。 相似文献
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Alkenes and sulfides were oxidized with transition-metal catalysts. The oxidant sources include molecular dioxygen, air and iodosylbenzene. The metal ions Mn(III), Fe(III), Co(II) and Ni(II) were used. The Catalysts 1-18 of 1,3-dioxo-, β-ketoimine- or salen-types were prepared and their efficacy was examined. 1,2-Dihydronaphthalene is most efficiently epoxidized with O2/Me2CHCHO or PhIO in the presence of Mn(III)-salen catalysts. The Ni(II)-, Co(II)- and Fe(III)-catalysts of either β-ketoimine- or salen-types are useful for epoxidation of styrene, (E)-stilbene and (E)-benzalacetone in the O2/Me2HCHO system; these epoxidations are stereospecific without formation of corresponding diastereomeric epoxides. Oxidation of methyl p-tolyl sulfide with O2/Me2CHCHO is facilitated by the 1,3-dioxo-catalyst Co(II)-1. Monooxidation is achieved with Me2CHCHO in equimolar proportions to give the corresponding sulfoxide, whereas overoxidation is realized with excess Me2CHCHO to give the sulfone. These epoxidation and sulfide oxidations all occur at 25 °C and are complete in less than a day. 相似文献
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A. S. Chikunov O. P. Taran A. A. Shubin I. L. Zilberberg V. N. Parmon 《Kinetics and Catalysis》2018,59(1):23-47
Surveyed in this review are the most important achievements in the research and development of catalysts based on Mn, Fe, Co, and Cu hydroxides for the oxidation of water to molecular oxygen by chemical oxidizing agents obtained, for the most part, at Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences. An analysis of the results of kinetic studies on water oxidation in the presence of the above-menthioned catalysts together with data obtained by quantum chemistry methods allowed us to make a conclusion on the general nature and process mechanism both in the presence of artificial catalytic systems based on metal hydroxides and the natural enzyme photosystem II of green plants. The most important properties of hydroxo compounds responsible for catalytic activity in the oxidation of water by one-electron oxidants are discussed, and a possible reaction mechanism is considered. 相似文献
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Simple and Efficient Ruthenium‐Catalyzed Oxidation of Primary Alcohols with Molecular Oxygen 下载免费PDF全文
Ritwika Ray Shubhadeep Chandra Prof. Debabrata Maiti Prof. Goutam Kumar Lahiri 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(26):8814-8822
Oxidative transformations utilizing molecular oxygen (O2) as the stoichiometric oxidant are of paramount importance in organic synthesis from ecological and economical perspectives. Alcohol oxidation reactions that employ O2 are scarce in homogeneous catalysis and the efficacy of such systems has been constrained by limited substrate scope (most involve secondary alcohol oxidation) or practical factors, such as the need for an excess of base or an additive. Catalytic systems employing O2 as the “primary” oxidant, in the absence of any additive, are rare. A solution to this longstanding issue is offered by the development of an efficient ruthenium‐catalyzed oxidation protocol, which enables smooth oxidation of a wide variety of primary, as well as secondary benzylic, allylic, heterocyclic, and aliphatic, alcohols with molecular oxygen as the primary oxidant and without any base or hydrogen‐ or electron‐transfer agents. Most importantly, a high degree of selectivity during alcohol oxidation has been predicted for complex settings. Preliminary mechanistic studies including 18O labeling established the in situ formation of an oxo–ruthenium intermediate as the active catalytic species in the cycle and involvement of a two‐electron hydride transfer in the rate‐limiting step. 相似文献
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Knoevenagel reactions involving carbonyl compounds and active methylene derivatives have been studied in the presence of alumina, KSF and K10 montmorillonites. With addition of water the ester group undergoes hydrolysis. A route is disclosed for the synthesis of coumarine compounds catalyzed by solid supports. 相似文献
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The metal-catalyzed Baeyer-Villiger oxidation of cyclohexanone with molecular oxygen (latm) in the presence of benzaldehyde gives δ -caprolactone in high yield. The same oxidation in the absence of metal catalysts is also studied. Additives to the system can improve the reaction highly efficiently. 相似文献
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Irina V. Il'ina Konstantin P. Volcho Dina V. Korchagina Nariman F. Salakhutdinov 《Helvetica chimica acta》2016,99(5):373-377
A new simple method has been developed for isolation of geranial from citral, which is a mixture of two isomeric aldehydes, geranial and neral. The storage of citral in the presence of K10 montmorillonite clay has been demonstrated to result in an almost complete conversion of neral to dimeric and oligomeric products, with most geranial remaining unconverted. This enables isolation of geranial with the yield of up to 94%, based on the amount of geranial originally present in citral. 相似文献
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《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2107-2110
Alcohols were oxidized to their corresponding carbonyl compounds with KBrO 3 in the presence of silica chloride and wet SiO 2 , in solution and under solvent free conditions. 相似文献
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5-Ethyl-3-methyl-2′,4′:3′,5′-di-O-methylenedioxyriboflavinium perchlorate (1, DMRFlEt+ClO4 –), derived readily from commercially available vitamin B2 (riboflavin), exhibits high catalytic activity for the oxidation of organic sulfides with hydrogen peroxide. The reaction provides an efficient and selective method for the oxidative transformation of organic sulfides to the corresponding sulfoxides under mild conditions. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.] 相似文献
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Solvent-Free Condensation of Methyl Pyridinium and Quinolinium Salts with Aldehydes Catalyzed by DBU
Methylpyridinium and methylquinolinium salts were condensed under solvent-free conditions with aromatic aldehydes in the presence of 1,8-diazabicyclo[5.4.]undec-7-ene (DBU) as catalyst, by grinding at room temperature. The products are dyes or useful intermediates. The DBU can be easily recycled and reused. 相似文献
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A mild and efficient method has been reported for preparation of Schiff base ligands through condensation reaction of various aromatic aldehydes and ketones with different aromatic amines in the presence of montmorillonite as a heterogeneous catalyst under solvent free conditions. The advantages of this friendly, economically, environmentally and mild method are such as; simplicity of the reaction procedure, reusability of catalyst, simple work‐up, high product yields and very short reaction times. 相似文献
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A Novel Method for Epoxidation of Cyclohexene Catalyzed by Fe2O3 with Molecular Oxygen and Aldehydes
A novel method for the epoxidation of cyclohexene using molecular oxygen (latm) and aldehyde in the presence of Fe2O3 is presented. The yields of epoxide highly increased by using this method. 相似文献
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A variety of sulfides have been oxidized to sulfoxides utilizing pyridinium tribromide in the presence of hydrated silica gel in a non‐aqueous media. A combination of pyridinium tribromide and hydrated silica gel releases molecular bromine slowly in the reaction, affecting the oxidation. Hydrated silica gel also promotes decomposition of the bromosulfonium intermediate to the product. This procedure employs non‐aqueous media for the first time in such a reaction. 相似文献