- Dinuclear μ-alkylidene complexes of transition metals as models for the transformation of CH2X2 (X=Cl, Br, I) into malonic acid derivatives by double carbonylation reactions
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The carbonylation of the μ-alkylidene complexes Fe2(CO)8CH2 (1) and Pd2I2(PPh2CH2PPh2)2CH2 (2) has been studied under a variety of conditions.In the presence of an alcohol ROH, complex 1 gives mainly the acetate CH3CO2R, the product of monocarbonylation, whereas under the same conditions complex 2 gives the malonate CH2(CO2R)2, the product of dicarbonylation.The mechanisms of both reactions are discussed.From the fraction involving 1 a mononuclear complex resulting from the dimerization of ketene has been isolated, and its structure established by an X-ray diffraction study.Olefins such as ethene and norbornene are able to trap the ketene intermediate.The possible participation of such μ-alkylidene complexes in the direct transformation of CH2X2 (X=Cl, Br, I) into malonic acid derivatives is discussed.
- Denise, B.,Navarre, D.,Rudler, H.,Daran, J. C.
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Read Online
- Preparation method of ethylene glycol monobutyl ether acetate
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The invention discloses a preparation method of ethylene glycol monobutyl ether acetate. The preparation method includes: using ethylene glycol monobutyl ether and acetic acid as raw materials, toluenesulfonic acid as a catalyst and normal propyl alcohol as a dewatering agent; performing heating backflow twice to obtain high-purity ethylene glycol monobutyl ether acetate. Compared with the prior art, the preparation method has the advantages that through multiple times of heating distillation, purity of a finished product is improved, and impurity content is reduced.
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Paragraph 0012; 0013
(2017/01/02)
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- Method of Fabricating Glycol Monoalkyl Ether Acetate Using Acidic Ionic Liquid Catalyst
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A new method for fabricating glycol monoalkyl ether acetate (GMAEA) is provided. A Bronsted acidic ionic liquid is used. After some reactions, two layers of materials are formed. A product of GMAEA is obtained at the upper layer. The lower layer is the ionic liquid. Thus, the ionic liquid is reusable for re-fabricating the product. And, furthermore, waste acid is reduced.
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Page/Page column 4
(2011/08/06)
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- Synthesis of immobilized Br?nsted acidic ionic liquid on silica gel as heterogeneous catalyst for esterification
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The Br?nsted acidic ionic liquid 1-(propyl-3-sulfonate) vinylimidazolium hydrogen sulfate ([(CH2)3SO 3HVIm]HSO4) was immobilized on the silica gel using tetraethoxysilane (TEOS) as silica source. The properties of samples were characterized by FT-IR, elemental analysis and TG. The results showed that [(CH2)3SO3HVIm]HSO4 had been successfully immobilized onto the silica gel, and the immobilized ionic liquid catalyst (IL/silica gel) had good thermal stability. Moreover, the IL/silica gel exhibited high catalytic activity for a series of esterification and could be separated from the reaction mixture easily. It also remained satisfactory catalytic activity for the synthesis of n-Butyl acetate after 7 times recycling.
- Miao, Jinmei,Wan, Hui,Guan, Guofeng
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experimental part
p. 353 - 356
(2011/09/21)
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- Reusable and efficient polystyrene-supported acidic ionic liquid catalyst for esterifications
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Polystyrene (PS)-supported 1-(propyl-3-sulfonate) imidazolium hydrosulfate acidic ionic liquid (PS-CH2-[SO3H-pIM][HSO4]) catalyst was prepared by supporting the ionic liquid onto highly cross-linked chloromethylated polystyrene (PS-CH2Cl). FT-IR, SEM and TG-DSC were employed to characterize the structure and property of the catalyst. Results suggested that acidic ionic liquid was supported onto the surface of PS-CH 2Cl by covalent bond. The original rough surface of PS-CH 2Cl was covered with acidic ionic liquid, forming a compact and thin surface layer, and its size had no obvious change. Moreover, the PS-CH 2-[SO3H-pIM][HSO4] catalyst showed a better thermal stability than that of PS-CH2Cl support. It also exhibited high catalytic activity for a series of esterifications. After the catalyst was reused for 13 times in the synthesis of n-butyl acetate, the yield only decreased 7.3%. A reaction mechanism of esterification over this new catalyst was proposed as well.
- Xu, Zhenjin,Wan, Hui,Miao, Jinmei,Han, Mingjuan,Yang, Cao,Guan, Guofeng
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experimental part
p. 152 - 157
(2011/01/05)
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- Continuous process for producing esters
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A process for the continuous and simultaneous manufacture of at least two different acetates by at least two simultaneous transesterification reactions comprising continuously bringing into contact in the presence of a catalyst in a reaction zone: (i) an acetate of the formula CH3COOR in which R is an alkyl radical, with (ii) at least two alcohols of formulae R1OH and R2OH in which R1and R2, are different, and are alkyl radicals with a linear or branched chain, or radicals of formula R3(OCH2CR4R5)m— in which R3is an alkyl radical, R4and R5, being identical or different, are a hydrogen atom or an alkyl radical, and m is an integer of from 1 to 4 to form a reaction mixture having a homogeneous liquid phase and produce in the reaction zone by at least two simultaneous transesterification reactions of (i) with (ii) at least two acetates of formulae CH3COOR1and CH3COOR2and continuously drawing off from the reaction zone the at least two acetates and continuously separating the at least two acetates from each other by at least twice successively distilling the reaction mixture present in the reaction zone.
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- Acylation of alcohols and amines with vinyl acetates catalyzed by Cp*2Sm(thf)2
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Cp*2Sm(thf)2 was found to be an efficient catalyst for the acylation of alcohols and amines with esters under mild conditions. In the present acylation, vinyl and isopropenyl acetates served as good acylating agents. Thus, a variety of alcohols and amines underwent acylation with vinyl and isopropenyl acetates in the presence of Cp*2Sm(thf)2 to give the corresponding esters and amides in good to excellent yields. This catalytic acylation of alcohols and amines offers an additional useful method by the use of various esters, instead of acid anhydrides and acid chlorides, as acylating agents under very mild conditions.
- Ishii, Yasutaka,Takeno, Mitsuhiro,Kawasaki, Yumi,Muromachi, Akifumi,Nishiyama, Yutaka,Sakaguchi, Satoshi
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p. 3088 - 3092
(2007/10/03)
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- Selective formation of malonate by a double CO insertion reaction into a μ-alkylidene complex of palladium
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Whereas μ-alkylidene complex Fe2 reacts with CO and ROH to give mainly the ester CH3CO2R, the μ-alkylidene complex Pd2I2 gives malonate CH2(CO2R)2 with a selectivity of 88percent.
- Denise, B.,Navarre, D.,Rudler, H.
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p. C83 - C85
(2007/10/02)
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