离子液体[Bmim]PF_6中醇氧化成醛酮的反应研究

利用DMSO和AC2O氧化醛酮反应的方法,研究了在离子液体[Bmim]PF6中,由一级和二级醇氧化成相应的醛酬的反应.结果表明,此反应条件温和,产率高,并且不会被进一步氧化成羧酸,后处理简单,离子液也可以重复使用.     

丙二酰氧基硼氢化钠介入的醛、酮还原胺化反应

叙述了在原位生成的丙二酰氧基硼氢化钠存在下的醛、酮还原胺化反应。讨论了还原胺化的反应条件和立体位阻效应,发现丙二酰氧基硼氢化钠是一个高选择性还原剂,在给定条件下不发生自身还原反应。     

A convenient preparative method for mintlactone and isomintlactone

Various 2-(2′-hydroxy-4′-methyl-1′-cyclohexylidene) carboxylic acid lactones were synthesised in good yield from carboxylic acids and 4-methylcyclohexanone. For example, mintlactone ( VI ) and isomintlactone ( VII ) were prepared from 2-(1′- hydroxy-4′-methylcyclohexan-1′-yl) propanoic acid ( III ) which was obtained by reaction of propanoic acid ( I ) with 4-methylcyclohexanone ( II ) using lithium naphthalenide in the presence of diethylamine. Compound ( VI ) could be separated from compound ( VII ) by silica gel column chromatography. Several new 2-(2′- hydroxy-4′-methyl-1′-cyclohexylidene) carboxylic acid lactones which may be used as perfumery materials, were obtained in good yield by this method.     

Inhibition of horse liver and yeast alcohol dehydrogenase by aromatic and aliphatic aldehydes

The reactivity of yeast alcohol dehydrogenase (YADH) and horse liver alcohol dehydrogenase (HLADH) towards 12 different aldehydes was tested. YADH was inhibited by pre-incubation with citral, citronellal, p-cuminaldehyde, p-anisaldehyde, m-tolualdehyde, trans-cinnamaldehyde, salicylaldehyde, p-hydroxybenzaldehyde and benzaldehyde, although of these aldehydes only trans-cinnamaldehyde acted as a substrate for the enzyme. HLADH was inhibited, to a much smaller extent, by pre-incubation with citral, salicylaldehyde, citronellal, p-anisaldehyde, piperonaldehyde, trans-cinnamaldehyde, p-hydroxybenzaldehyde and p-cuminaldehyde and all of these aldehydes acted as substrates for the HLADH. Immobilisation of the enzymes on CNBr-activated Sepharose 4B gave protection against inhibition by the aldehydes, suggesting a means of significantly extending the useful lifetime of the enzymes when they are used in industrial processes.     

Au nanocolloids as recyclable quasihomogeneous metal catalysts in the chemoselective hydrogenation of α,β-unsaturated aldehydes and ketones to allylic alcohols

In the catalytic hydrogenation of α,β-unsaturated aldehydes and ketones, highly selective allylic alcohol formation can be achieved by application of Au⁰ nanocolloids dispersed in amide solvents. The polyvinylpyrrolidone protected Au⁰ nanoparticles prefer CO reduction over CC saturation and act as chemoselective quasihomogeneous metal catalysts in the hydrogenation of trans-2-butenal (crotonaldehyde), 2-methyl-2-propenal (methacrolein), 4-methyl-3-penten-2-one (mesityl oxide) and 3-methyl-3-penten-2-one. An extensive solvent screening revealed the superiority of amides as media for both synthesis and application of the Au⁰ nanocolloids. In comparison with the widely used alcohol solvents, amides offer enhanced colloidal stability for the Au⁰ nanosol and increased hydrogenation chemoselectivity. Control over the Au⁰ cluster formation provided the opportunity to investigate the size-dependency of the catalytic performance and to determine the optimum gold cluster size for a maximization of the allylic alcohol yields. The most successful Au⁰ clusters, with a typical diameter of 7 nm and synthesized in N,N-dimethylformamide, lead to a crotyl alcohol selectivity of 73% at 93% crotonaldehyde conversion and a 58% allylic alcohol yield in the hydrogenation of mesityl oxide at a molar substrate/Au catalyst ratio of 200. Analogous Pt⁰ and Ru⁰ sols are more active than the Au⁰ nanosols, but substantially less chemoselective for allylic alcohols. The Au⁰ nanocolloids can be recycled efficiently by ultrafiltration over custom-made, cross-linked polyimide membranes. In the recycling experiments the gold nanodispersion was well retained by the solvent-resistant ultrafiltration membranes and the performance of the colloidal gold catalyst was satisfactorily preserved in successive hydrogenation runs.     

Photografting of methyl methacrylate onto high‐density polyethylene initiated by aliphatic ketones

The photografting of a water‐insoluble monomer methyl methacrylate (MMA) onto high‐density polyethylene (HDPE) initiated by an aliphatic ketone/water/alcohol initiating system has been reported. The aliphatic ketones, such as acetone, butanone, and cyclohexanone, could effectively initiate the grafting reaction when they were mixed with water and ethanol to form homogeneous aliphatic ketone/water/ethanol mixed solvents that could dissolve the water‐insoluble monomer. The nature of aliphatic ketone affected the grafting; at the same aliphatic ketone/water/ethanol volume ratio, the grafting system containing acetone or butanone always led to a higher extent of grafting than that containing cyclohexanone. Water also played a very important role in the grafting reaction; in the tested range, the rate of formation of grafted PMMA on HDPE increased with the increase of water : volume ratio. The grafting of MMA carried out in 5 acetone/40 water/55 ethanol mixed solvent led to the highest extent of grafting. ATR‐FTIR characterizations of the grafted samples proved the successful grafting of MMA onto HDPE. SEM investigations of the HDPE surfaces grafted in different aliphatic ketone/water/ethanol mixed solvents indicate the morphologies of grafted surfaces varied with the mixed solvents used. This study broadened the application fields of the aliphatic ketone/water/alcohol initiating system for photografting. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of acid and pH value on the photografting initiated by aliphatic ketones in aqueous solutions

The photografting of methacrylic acid (MAA) onto high‐density polyethylene (HDPE) initiated by aliphatic ketones (acetone, butanone, and cyclohexanone) in aqueous solutions with different pH values adjusted by adding different amount of mineral acids was reported. Acids significantly enhanced the photografting yield, and the extent of grafting generally increased with decreasing pH value. The effect of pH value on the grafting reactions varied with the acid used. The grafting of MAA onto HDPE surface was confirmed with FTIR and SEM characterizations. The water absorbency of the grafted p‐MAA varied with the extent of grafting. When the extent of grafting was less than 2000–3000 μg/cm², grafted p‐MAA absorbed about 25–30% water, whereas at higher extent of grafting, it absorbed about 50% water. The mechanism of the acid enhancement of the photografting of MAA initiated by aliphatic ketones in aqueous solutions is believed to be attributed to the change of the solubility of monomer in the solution and the conformation of grafted chains, both are favorable for accelerating grafting reactions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Oxidation of benzyl alcohols to ketones and aldehydes by O3 process enhanced using high-gravity technology

In this study, a practical process for ozonization of benzyl alcohols to ketones and aldehydes in a rotating packed bed(RPB-O_3) reactor has been developed. Using 1-phenylethanol as a model reactant, the performance of RPB-O_3 process in different solvents has been compared with the commonly used stirred tank reactor(STR-O_3). Ethyl acetate was the optimum solvent for the conversion of 1-phenylenthanol to acetophenone in RPB-O_3 process, with 78% yield after 30 min. In a parallel STR-O_3 experiment, the yield of acetophenone was50%. Other experimental variables, i.e. O_3 concentration, reaction time, high-gravity factor and liquid flow rate were also optimized. The highest yield of acetophenone was obtained using O_3 concentration of 80 mg·L~(-1),reaction time of 30 min, high gravity factor of 40 and liquid flow rate of 120 L·h~(-1). Under the optimized reaction conditions, a series of structurally diverse primary and secondary alcohols was oxidized with(19%–92%) yield.The ozonization mechanism was studied by Electron Paramagnetic Resonance(EPR) spectroscopy, monitoring the radical species formed upon self-decomposition of O_3. The characteristic quadruple peak with the 1:2:2:1 intensity ratio that corresponds to hydroxyl radicals(·OH) was observed in the electron paramagnetic resonance(EPR) spectrum, indicating an indirect oxidation mechanism of alcohols via ·OH radical.     

Kinetic study of hydrogen transfer from benzyl alcohol to aliphatic aldehydes catalysed by heterogenised ruthenium(II) catalysts

Aliphatic aldehydes were reduced to corresponding alcohols by transfer hydrogenation in the presence of Ru(II) complexes bound to swellable polymer matrices. Benzyl alcohol was used as hydrogen donor because of its strong hydrogen donor ability. The kinetics of the reaction has been measured between 100 and 140°C. The results showed that reaction rate depended on the structure of aldehydes and concentrations of aldehyde. Also reaction rate depended on the concentration of hydrogen donor, and on the amount of catalyst. The reaction proceeded efficiently in halogenated hydrocarbon solvents. The metal leaching was different for different catalytic runs and it was most pronounced in the first catalytic run. The observed activation energy, E_a = 18 ± 1 kcal/mol was obtained, suggested that process in predominantly chemically controlled reaction. A general reaction mechanism and rate equation have been proposed.     

A convenient preparative method of 3-hydroxy acids,and the reaction of 3-hydroxy acids with acidic materials

3-Hydroxy acids were synthesised in good yield from ketones and carboxylic acids using lithium naphthalenide in the presence of diethylamine. From cyclohexanone and propionic acid, 2-(1′-hydroxycyclohexan-1′-yl) propionic acid ( I ) was obtained in 98.3% yield. 3-Hydroxy acids were treated with various acidic materials to give 3,4-unsaturated carboxylic acids and γ-butyrolactones. From the reaction of ( I ) with p-toluenesulphonic acid or potassium bisulphate, 2-(cyclohexen-1′-yl) propionic acid ( II ) (a 3,4-unsaturated acid) was obtained (yield 98%), and with 97% sulphuric acid 2-(1′-hydroxycyclohexan-1′-yl) propionic acid lactone ( III ) was formed (93% yield). Several new γ-butyrolactones were obtained in good yield by this method.     

液相色谱─间接光度检测测定脂族醇

在化学键合固定相ＯＤＳ柱（２５０ｍｍ×４．６ｍｍ内径）上,用Ｒｕ（Ｐｈｅｎ）２＋３作甲醇┐水（８９２,Ｖ／Ｖ）流动相添加剂分离并用间接光度法检测某些脂族醇。探讨了流动相中有机溶剂浓度、Ｒｕ（Ｐｈｅｎ）２＋３浓度、ｐＨ值和盐浓度等对醇类的保留时间和检测灵敏度的影响。甲醇、乙醇、正丙醇、异丙醇、正丁醇和叔丁醇具有良好的分离度和检测灵敏度,间接光度法检测可在４５０ｎｍ处,也可在３３０ｎｍ处。同时测定此６种醇的校正曲线线性范围,甲醇、乙醇各为０．５～５０ｍｇ／ｍＬ,其余４种醇各为１～１００ｍｇ／ｍＬ,绝对检测限达微克级。     

Preparation of Pd-Ag thin films by the RF-sputtering method and its catalysis for oxidative dehydrogenation of allylic alcohols

Pd-Ag thin films were prepared by the RF sputtering method on a Pyrex glass substrate to give monophasic alloys. Oxidation of allylic alcohols using the films gave selectively , -unsaturated carbonyl compounds in the presence of O₂; highly dispersed Pd species on Ag, Pd₇Ag₉₃ showed 95% selectivity for acrolein from allyl alcohol at 473 K.     

Aerobic oxidation of secondary alcohols to ketones catalyzed by cobalt(II)/ZnO in poly(ethylene glycol)/CO2 system

The aerobic oxidation of benzhydrol, 1-phenylethanol and cyclohexanol to corresponding ketones was carried out in poly(ethylene glycol) (PEG-600)/supercritical CO₂ (SCCO₂) biphasic system using unsupported and supported CoCl₂·6H₂O as the catalysts. It was demonstrated that CoCl₂·6H₂O, Co(II)/Al₂O₃, and Co(II)/ZnO were all active and selective for the reactions. The reactivity of the substrates followed the order benzhydrol > 1-phenylethanol > cyclohexanol. Co(II)/ZnO was most stable and could be reused four times without considerable reduction of activity. The effect of CO₂ pressure, reaction time and solvent was further investigated. The Co(II)/ZnO/PEG-600 system is active, selective, cheap, clean, and recyclable for the aerobic oxidation of secondary alcohols.     

A comparison of surfactants derived from alcohols based on petrochemical and oleochemical sources

Samples of lauryl-range alcohols derived from palm kernel oil, coconut oil and ethylene (Ziegler) were derivatized into alcohol sulfates and alcohol ether sulfates (2 moles of ethylene oxide adduct). Physical properties and performance characteristics for earch surfactant were evaluated both individually and in light-duty liquid (LDL) dish-washing formulations. The slight differences observed in the physical and performance properties of the surfactants and their formulations were assignable to slight differences the individual alcohol, alcohol sulfate and alcohol ether sulfate samples employed in this study. The magnitude and type of variation found in the samples resulted from normal production variation and not from any properties inherent to the nature of the alcohol source. We therefore conclude that alcohol sulfates, alcohol ether sulfates and LDLs formulated from them exhibit identical physical property and performance characteristics, regardless of whether the original alcohol was manufactured from petrochemical or eleochemical sources.     

A rapid and convenient method for measuring the swelling of coals by solvents

The volumetric swelling procedure developed by Liotta was applied to a pair of coals using 10 solvents. The results were compared with the results of gravimetric swelling experiments. Good straight-line correlations having slopes of 0.93 (Bruceton coal) and 1.01 (III. No. 6 coal) were observed. The much more rapid and convenient volumetric swelling procedure gives the same results as the gravimetric procedure. Additionally, no correction for pore volume is necessary with the volumetric procedure. From plots of the gravimetric vs. volumetric swells, the accessbile pore volumes of the coals can be determined. They are 21% and 15% for Bruceton and III. No. 6 coals, respectively.     

室温条件下4-OH-TEMPO体系高效选择催化氧化苄醇为醛的研究

报道了以TMEDA(N,N,N’,N’-四甲基乙二胺)为促进剂,与4-OH-TEMPO(4-羟基-2,2,4,4,-四甲基-哌啶氮氧自由基)和CuC l组成催化体系,在室温条件下用空气为氧化剂高转化率、高选择性催化氧化苄醇为相应芳香醛的方法,氧化速率快。研究结果表明,胺在4-O-TEMPO催化体系中起到重要作用,碱的促进作用与胺的碱性和空间位阻有关,TMEDAD的效果最佳。     

对氨基苯磺酸铝催化苯乙酮、芳香醛和芳香胺的“一锅法”Mannich反应

室温条件下,对氨基苯磺酸铝可有效催化苯乙酮、芳香醛和芳香胺的Mannich反应,三组分"一锅法"合成了系列β-氨基酮衍生物。考察了反应条件对收率的影响及对氨基苯磺酸铝对不同底物Mannich反应的催化效果,推测了反应机理。产物结构经IR、~1H NMR和质谱进行表征。合成不同的β-氨基酮衍生物的较佳反应条件为:苯乙酮、芳香醛和芳香胺物质的量比为1.1:1:1,对氨基苯磺酸铝用量为苯甲醛物质的量的3%,乙醇用量5 mL。该方法操作简单,条件温和,收率高,催化剂可重复使用,对环境友好。     

A convenient and efficient method for the synthesis of benzo- and naphthothiazolediones

A series of benzo- and naphthothiazolediones have been synthesized by the reactions of N-substituted thioureas with π-deficient quinones. The products were obtained by the reaction of N-aroylphenylthioureas with 2,3,5,6-tetracholoro-1,4-benzoquinone, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and 2,3-dichloro-1,4-naphthoquinone.     

一步法合成烯丙基缩水甘油醚的研究

烯丙基缩水甘油醚是一种脂肪族缩水甘油醚,可以用作聚合单体和有机合成中间体,是合成硅烷偶联剂KH560的主要原料。实验研究了以环氧氯丙烷和烯丙醇为原料,在一定的相转移催化剂条件下,直接合成烯丙基缩水甘油醚。考察了反应温度、反应时间、物料物质的量比、催化剂体系、带水剂体系对反应产率的影响,确定了最佳的合成工艺条件。     

光照及需氧条件下Al2O3-AlBrx催化醇的选择性氧化反应

以脱脂棉为模板制备了多孔管状结构的Al2O3材料,用不同浓度的氢溴酸对多孔管状结构的Al2O3材料进行化学剪裁,制备了活性量可控,比表面积可调,不同形貌的负载型催化剂Al2O3-AlBr x。采用电场发射扫描电镜(SEM)和X射线衍射仪(XRD)对催化剂进行了表征。结果表明,该催化剂较好地复制了棉纤维的宏观和微观结构,呈现出明显的生物形貌特征。在光照条件下以空气为氧化剂的醇的选择性氧化反应中,发现催化剂Al2O3-AlBr x-3可以高选择性地将醇氧化为相应的醛、酮或酸,并对反应机理进行了探讨。该催化剂循环使用3次仍保持较高的催化活性。