- Cyanide selective chemodosimeter in aqueous medium, on test strips and its application in real sample analysis
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Abstract: In this paper, synthesis, characterization and detection of CN? by the compound (N′1E,N′2E)-N′1,N′2-bis((2-hydroxynaphthalen-1-yl)methylene)oxalohydrazide (1) have been reported. Compound 1 is synthesized by the reaction of oxalyldihydrazide and 2-hydroxy-1-naphthaldehyde and characterized by FTIR, 1H NMR and ESI-Mass spectroscopy. UV–Visible spectral band of 1 is observed to be broadened and shifted to longer wavelength upon addition of CN? ion selectively in H2O-DMSO (8:2 v/v) medium. Based on the UV–Visible spectral data, the detection limit of cyanide ion for 1 is found to be 30.2 μM. Colourless solution of 1 changes to yellow in the presence of cyanide ion selectively. The same colour change is also observed on Whatman filter paper test strip. Fluorescence intensity of 1 is quenched due to the nucleophilic addition reaction of cyanide with one of the two imine carbons. 1H NMR titration of 1 with CN? ion corroborates the reaction of the latter with one of the two imine carbons of the former, leading to the appearance of cyanomethyl proton signal at 6.15 ppm and consequently, its behaviour as chemodosimeter. The above mentioned chemodosimeter nature of 1 is also validated by ESI-Mass spectroscopy data. Compound 1 is capable for the detection of CN? in water for real samples with concomitant colour change. Graphic abstract: Compound 1 behaves as selective cyanide chemodosimeter with associated change in its colour (in solution and on Whatman filter paper test strip) and fluorescence. 1H NMR titration and ESI-Mass data confirm the nucleophilic addition reaction of cyanide with 1. Compound 1 can be used for the detection of CN? in water for real samples.[Figure not available: see fulltext.].
- Ghosh, Tamal,Raina, Ashish,Singh, Yadvendra,Yadav, Komal Kumar
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Read Online
- Highly active Pd-Fe/α-Al2O3 catalyst with the bayberry tannin as chelating promoter for CO oxidative coupling to diethyl oxalate
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A novel Pd-Fe/α-Al2O3 catalyst was synthesized by incipient-wetness impregnation method with bayberry tannin as chelating promoter and commercial hollow column Raschig ring α-Al2O3 as support for the synthesis of diethyl oxalate from CO and ethyl nitrite. A variety of characterization techniques including N2 physical adsorption, optical microscopy, scanning electron microscopy and energy dispersive system (SEM-EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), were employed to explore the relationship between the physicochemical properties and activity of catalysts. It indicated that a large number of phenolic hydroxyl groups in bayberry tannin can efficiently anchor the active component Pd, reduce the particle size and make the active Pd as a multi-ring distribution on the commercial α-Al2O3 support, which were beneficial to improve the catalytic activity for the production of diethyl oxalate from CO and ethyl nitrite. 0.3 wt% Pd-Fe/α-Al2O3 showed excellent catalytic activity and selectivity in a continuous flow, fixed-bed reactor with the loading amount of 10 mL catalysts. Under the mild reaction conditions, the space-time yield of diethyl oxalate was 978 g L?1 h?1 and CO conversion was 44% with the selectivity to diethyl oxalate of 95.5%.
- Xing, Wei-Chao,An, Ji-Min,Lv, Jing,Irshad, Faisal,Zhao, Yu-Jun,Wang, Sheng-Ping,Ma, Xin-Bin
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Read Online
- A nanostructured CeO2 promoted Pd/α-alumina diethyl oxalate catalyst with high activity and stability
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A Pd/α-Al2O3 nanocatalyst was synthesized and investigated as a catalyst for CO oxidative coupling to diethyl oxalate and CeO2 was used as a promoter. With the highest activity and stability found so far, great CO conversion and diethyl oxalate selectivity were achieved due to the addition of CeO2. This journal is
- Jin, Erlei,He, Leilei,Zhang, Yulong,Richard, Anthony R.,Fan, Maohong
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Read Online
- One-pot production of diethyl maleate via catalytic conversion of raw lignocellulosic biomass
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The conversion of lignocellulose into a value-added chemical with high selectivity is of great significance but is a big challenge due to the structural diversities of biomass components. Here, we have reported an efficient approach for the one-step conversion of raw lignocellulose into diethyl maleate by the polyoxometalate ionic liquid [BSmim]CuPW12O40 in ethanol under mild conditions. The results reveal that all of the fractions in biomass, i.e., cellulose, lignin and hemicellulose, were simultaneously converted into diethyl maleate (DEM), achieving a 329.6 mg g-1 yield and 70.3% selectivity from corn stalk. Importantly, the performance of the ionic liquid catalyst [BSmim]CuPW12O40 was nearly twice that of CuHPW12O40, which can be attributed to the lower incorporation of the Cu2+ site in [BSmim]CuPW12O40. Hence, this process opens a promising route for producing bio-based bulk chemicals from raw lignocellulose without any pretreatment.
- Cai, Zhenping,Chen, Rujia,Zhang, Hao,Li, Fukun,Long, Jinxing,Jiang, Lilong,Li, Xuehui
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supporting information
p. 10116 - 10122
(2021/12/24)
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- Method for continuously producing diethyl oxalate
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The invention provides a method for continuously producing diethyl oxalate. The method comprises the following steps: A) adding dimethyl oxalate, alcohol and a catalyst into a first reaction kettle, carrying out ester exchange reaction, continuously and sequentially feeding reaction liquid into a second reaction kettle, a third reaction kettle and a fourth reaction kettle which are connected with the first reaction kettle in series, and continuously carrying out ester exchange reaction; and B) sequentially introducing the reaction liquid in the fourth reaction kettle into a dealcoholization tower, a byproduct removal tower and a product tower to obtain diethyl oxalate at the top of the product tower. The method has the advantages that: 1) four-kettle continuous reaction is adopted, so that the reaction rate and the conversion rate are improved; 2) the side reaction is less, the byproduct is single, the byproduct can be continuously reacted to obtain the product, the atom utilization rate is close to 100%, the product purity reaches 99.99%, and the purity of the co-produced methanol is 99% or above; and 3) environmental protection advantage: basically no three wastes are generated, the catalyst is recycled, and the method belongs to a clean production process and meets environmental protection requirements.
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Paragraph 0077-0091
(2021/06/21)
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- PROCESS FOR THE SYNTHESIS OF ETHYLENE GLYCOL
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The invention relates to a process for the production of ethylene glycol from CO2, comprising the steps of : i) Reducing CO2 to CO; ii) Reacting the CO produced in step i) with an amine to form an oxamide or an oxamate or with an alcohol to form an oxalate; and iii) Reducing the oxamide, oxamate or oxalate formed in step ii) to form ethylene glycol, a process for the production of an oxamide, oxamate or oxalate and a process for the production of polyethylene terephthalate.
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Page/Page column 49-51
(2021/10/11)
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- New series of γ-pyrone based podands: Synthesis, characterization and study of their application in acetate salts cation trapping for nucleophilic substitution reactions
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Dialkyl 4-oxo-4H-pyran-2,6-dicarboxylates are synthesized via esterification of chelidonic acid or via intramolecular cyclization of dialkyl-2,4,6-trioxoheptanedioates. Reaction of the dialkyl 4-oxo-4H-pyran-2,6-dicarboxylates with a variety of glycol monoalkyl ethers produces a series of new podands in good yields. To demonstrate the use of these podands in cation trapping, nucleophilic substitution reactions are carried out with various acetate salts. The results indicate that the cation diameter’s compatibility with binding site leads to the best yield of reaction.
- Teimuri-Mofrad, Reza,Aghaiepour, Alireza,Rahimpour, Keshvar
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p. 121 - 132
(2019/04/17)
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- Method for synthesizing symmetric oxalate by using dimethyl oxalate and alcohols in one step
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The invention relates to a method for synthesizing symmetric oxalate, in particular to a method for synthesizing the symmetric oxalate by using dimethyl oxalate and alcohols in one step. The symmetricoxalate is synthesized by using the dimethyl oxalate and the high carbon alcohols such as ethanol, propanol, butanol and pentanol as reaction raw materials and by adopting a one-step synthesis method. A catalyst used in the method is a mesoporous-microporous composite multifunctional basic catalyst, and has the advantages that mesopores significantly improve the mass transfer efficiency, while micropores significantly enlarge the specific surface area of a carrier and improve the dispersion of an active center. 10% MgO-5% Al2O3-8% Fe2O3/Na-meso-Y is used as the catalyst, the raw material ethanol and the dimethyl oxalate are enabled to be subjected to reaction under the atmospheric pressure at the temperature of 100 DEG C under the condition that the space velocity is 2 h-1, wherein the molar ratio of the raw material ethanol to the dimethyl oxalate is equal to 20 to 1; the selectivity of the product diethyl oxalate is stabilized to be about 82%, and the steady state operation is performed for 1000h; the catalytic activity and the product selectivity are basically unchanged. The whole reaction path has the characteristics of being short in synthetic route, simple in process flow and high in raw material conversion rate and product selectivity, and enabling the catalyst to be stable and non-deactivated.
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Paragraph 0033-0042
(2019/01/06)
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- Preparation method of methylallyl alcohol
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The invention discloses a preparation method of methylallyl alcohol. The method is characterized in that the methylallyl alcohol and a carboxylate compound are obtained by adopting methylallyl chloride and carboxylate as raw materials and alcohol as a solvent. The solvent creatively adopts the alcohol, not an alkali or other solvents, so reaction conditions are mild, and the irritation to the rawmaterials is low; and more importantly, the carboxylate also can be obtained, the content of ether and salt products is low, the yield of the target product is high, so the method in the invention hasadvantages over traditional technologies characterized by adoption of the alkali as a hydrolysis agent, a two-step reaction and high byproduct content.
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Paragraph 0024-0025
(2018/06/04)
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- Method for synthesizing diethyl oxalate through catalyzation of modified graphene
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The invention relates to a method for synthesizing diethyl oxalate through catalyzation of modified graphene. Enriched hydroxylated graphene oxide is added into a diethyl oxalate synthesization reactor before reaction, since the enriched hydroxylated graphene oxide has excellent physical and chemical properties, oxalic acid molecules and ethyl alcohol molecules efficiently and thoroughly react on the surface of the graphene, and the yield of the diethyl oxalate is increased to 99% or above from 93.3%. The method is simple and practical, the enriched hydroxylated graphene oxide can be recycled, and the method is low in cost and suitable for mass production.
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Paragraph 0013-0022
(2017/05/19)
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- β-oxalylamino-substituted O-ethyl N-arylcarbamates and N-ethyl-N′-arylureas encapsulated into micelles of vinylimidazole–vinylcaprolactam copolymer
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Low-molecular-weight compounds—β-oxalylamino-substituted O-ethyl carbamates and unsymmetrical ureas showing biological activity—have been synthesized and encapsulated into micelles of vinylimidazole–vinylcaprolactam copolymers. Solubilization in micelles has provided a preparation of water-soluble colloidal formulation of these compounds suitable for practical application.
- Vorob’ev,Kovalenko,Kalistratova,Oshchepkov,Filippova,Khodak,Kochetkov
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- POLYDIORGANOSILOXANE POLYMIDE COPOLYMERS HAVING ORGANIC SOFT SEGMENTS
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Polydiorganosiloxane polyamide, block copolymers having organic soft segments and methods of making the copolymers are provided.
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- Template-free sol–gel synthesis of high surface area mesoporous silica based catalysts for esterification of di-carboxylic acids
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High surface area mesoporous silica based catalysts have been prepared by a simple hydrolysis/sol–gel process without using any organic template and hydrothermal treatment. A controlled hydrolysis of ethyl silicate-40, an industrial bulk chemical, as a silica precursor, resulted in the formation of very high surface area (719?m2/g) mesoporous (pore size 67?? and pore volume 1.19?cc/g) silica. The formation of mesoporous silica has been correlated with the polymeric nature of the ethyl silicate-40 silica precursor which on hydrolysis and further condensation forms long chain silica species which hinders the formation of a close condensed structure thus creating larger pores resulting in the formation of high surface mesoporous silica. Ethyl silicate-40 was used further for preparing a solid acid catalyst by supporting molybdenum oxide nanoparticles on mesoporous silica by a simple hydrolysis sol–gel synthesis procedure. The catalysts showed very high acidity as determined by NH3-TPD with the presence of Lewis as well as Br?nsted acidity. These catalysts showed very high catalytic activity for esterification; a typical acid catalyzed organic transformation of various mono- and di-carboxylic acids with a range of alcohols. The in situ formed silicomolybdic acid heteropoly-anion species during the catalytic reactions were found to be catalytically active species for these reactions. Ethyl silicate-40, an industrial bulk silica precursor, has shown a good potential for its use as a silica precursor for the preparation of mesoporous silica based heterogeneous catalysts on a larger scale at a lower cost.
- More, Pavan M.,Umbarkar, Shubhangi B.,Dongare, Mohan K.
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p. 1247 - 1253
(2016/10/13)
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- A kind of preparation method of succinic acid diester
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Disclosed is a method for preparing succinic acid diester, in which levulinic acid or levulinate esters are used as raw materials, molecular oxygen is used as oxygen source, and succinic acid diester is produced by catalytic selective oxidation and esterification reaction. The levulinic acid or levulinate esters used as raw materials in the method can be obtained from biomass such as cellulose, starch, agricultural and forestry residues or the like. The method is a new route for preparing succinic acid diester that does not rely on fossil resourse. As the reaction condition in the process is moderate and has a high succinic acid diester selectivity, it has important application prospect.
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Paragraph 0073-0078
(2017/01/09)
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- Copolymers with perfluoropolyether segment and multiple aminooxalylamino groups
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Copolymers containing at least one perfluoropolyether segment and multiple aminooxalylamino groups are described. Methods of making the copolymers are also described. The copolymers can be prepared by reacting an oxalylamino-containing compound and an amine compound having at least two primary amino groups, at least two secondary amino groups, or at least one primary amino group plus at least one secondary amino group.
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- Oxone-mediated oxidative cleavage of β-keto esters and 1,3-diketones to α-keto esters and 1,2-diketones in aqueous medium
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A versatile and highly efficient method for the direct synthesis of α-keto esters and 1,2-diketones has been developed. This approach utilizes the oxidative cleavage of a variety of β-keto esters and 1,3-diketones mediated by an Oxone/aluminum trichloride system. The simple one-step oxidation reaction proceeded selectively in aqueous media to afford products in high yields, short reaction times, and environmentally benign conditions.
- Stergiou, Anastasios,Bariotaki, Anna,Kalaitzakis, Dimitris,Smonou, Ioulia
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p. 7268 - 7273
(2013/08/15)
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- Stereoselective control in the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents: Experimental investigation and theoretical rationalization
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The stereoselectivity of the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents was investigated experimentally by determination of the product stereochemistry and theoretically via DFT calculations. The results indicate that imines preferentially attack the less sterically hindered exo-side of the ketenes to generate zwitterionic intermediates. Subsequently, for cyclic imines, the intermediates undergo a conrotatory ring closure directly to produce β-lactams, while for linear imines, the imine moiety of the intermediates isomerizes to more stable intermediates, which further undergo a conrotatory ring closure to afford trans-β-lactams. The steric hindrance and the isomerization, rather than the torquoelectronic effect, play crucial roles in controlling the stereoselectivity in the practical Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents, although the unaccessible borylketene with a powerful electron acceptor group controls the stereoselectivity torquoelectronically, in theory.
- Qi, Hengzhen,Li, Xinyao,Xu, Jiaxi
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supporting information; experimental part
p. 2702 - 2714
(2011/05/19)
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- Preparation of silica-supported sulfate and its application as a stable and highly active solid acid catalyst
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Silica sulfate was prepared by a simple procedure, and proved to be an efficient and recyclable solid acid catalyst. SO3H groups were successfully introduced to silica surface while keeping its structure intact, as proved by XRD patterns and SEM images of the catalyst. With the catalysis of the supported sulfate materials, many of the ketones are efficiently transformed into the corresponding lactones with 30% hydrogen peroxide. In addition, the high performance of silica sulfate as a heterogeneous catalyst was further demonstrated for the esterification of varieties of carboxylic acid with ethanol.
- Yang, Zhi-Wang,Niu, Leng-Yuan,Jia, Xiao-Jie,Kang, Qiao-Xiang,Ma, Zhen-Hong,Lei, Zi-Qiang
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experimental part
p. 798 - 802
(2011/12/21)
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- Condensation of trifluoromethanesulfonamide with paraformaldehyde and oxamide
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Depending on the conditions, three-component condensation of trifluoromethanesulfonamide with paraformaldehyde and oxamide led to the formation of linear products, N-mono- and N,N'-bis[(trifluoromethylsulfonyl) aminomethyl]oxamide, bis[(trifluoromethylsulfonyl)aminomethyl] ethanedioate, as well as of hydrolysis and cyclization product, N-(4,5-dioxo-1,3-oxazolidin-3- ylmethyl)trifluoromethanesulfonamide.
- Meshcheryakov,Moskalik, M. Yu.,Starke,Shainyan
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experimental part
p. 1471 - 1475
(2011/03/18)
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- PROCESS FOR THE PRODUCTION OF ETHYLENE GLYCOL AND RELATED COMPOUNDS
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The present invention provide a process for the production of compounds of general formula (I), Y-CH2CH2-Z (I) wherein Y and Z are functional groups independently selected from the group consisting of a hydroxyl group and R1R2N and wherein R1 and R2 may be the same or different and are functional groups selected from the group consisting of hydrogen and substituted or non- substituited alkyl groups comprising 1 to 8 carbon atoms, or R1R2N is a cyclic compound selected from the group of aromatic and non-aromatic cyclic compounds optionally comprising one or more heteroatoms in addition to the nitrogen atom, said process comprising the steps of: (i) reacting carbon monoxide and an amine in the presence of oxygen to provide a compound of general formula (II) wherein R1 and R2 or R1R2N are as defined above and X is selected from the group consisting of R1R2N and R3O, wherein R3 is selected from alkyl groups comprising 1 to 8 carbon atoms; and (ii) converting the compound of general formula (II) into a compound of general formula (I) by a process that comprises a hydrogenation reaction.
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Page/Page column 9-10
(2010/12/17)
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- Processes for Producing an Oxalate by Coupling of CO
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Provided are processes for producing an oxalate by coupling of CO in the presence of a nitrite, wherein two or more reaction zones in series are used, and at least a portion of the oxalate as reaction product is separated between the reaction zones, and/or the nitrite is fed stagewise. The processes described herein can effectively enhance the selectivity to the oxalate and the single-pass conversion of the feedstock.
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Page/Page column 7
(2010/07/04)
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- A kinetic study of the solvolyses of methyl and ethyl chloroglyoxalates
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Solvolyses of methyl and ethyl chloroglyoxylates proceed about 10 6 times faster than the identical solvolyses of the corresponding chloroformates. The correlation parameters obtained from application of the extended Grunwald-Winstein equation are consistent with an addition-elimination (association-dissociation) mechanism over the full range of solvents, with the addition step being rate determining.
- Kevill, Dennis N.,Park, Byoung-Chun,Kyong, Jin Burm
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p. 9032 - 9035
(2007/10/03)
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- N-acylamino acid amide compounds and intermediates for preparation thereof
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The present invention discloses the compound represented by the formula (I): wherein A represents the following formula (a-1) or the following formula (a-2): B represents the following formula (b): (wherein the symbols are each as defined in the specification) or a pharmaceutically acceptable salts thereof, and intermediates for the preparation thereof, which have excellent platelet aggregation inhibitory activity and other properties and useful as prophylactic or therapeutic agents for diseases associated with a fibrinogen receptor, thrombosis, infarction and the like.
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- Derivatives of imidazole, their preparation process, the new intermediates obtained, their use as medicaments and the pharmaceutical compositions containing them
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The invention relates to the products of formula (I): STR1 in which: R1 =represents hydrogen, aryl, arylcarbonyl, arylthio, alkylcarbonyl, R2, R3 represent in particular halogen, mercapto, acyl, carboxy, nitro, cyano, amino, carbamoyl, R4, --OR4 with R4 representing in particular hydrogen, alkyl, alkenyl, alkynyl, acyl, amino, --(CH2)m1 --S(O)m2 --X--R10 with m1=0 to 4, m2=0 to 2, X represents a single bond or --NH--, --NH--CO--, --NH--CO--NH--, and R10 represents alkyl, alkenyl or aryl, and Y represents optionally substituted aryl, these products being in all isomer forms and salts, their use as medicaments.
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- Trans-esterification in dry media using ferric perchlorate adsorbed on silica gel
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Adsorption of Fe(ClO4)3(H2O)6 onto chromatographic grade silica gel in the presence of ethyl acetate (to be used for trans-esterification) produces a supported reagent, Fe(ClO4)3(EtOAc)6/SiO2. This reagent, has been found effective for the rapid and high yield of esters via trans- esterification on grinding in the presence of alcohols/carboxylic acids using pestle and mortar in the solid state.
- Parmar, Anupama,Goyal, Rita,Kumar, Baldev,Kumar, Harish
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p. 139 - 143
(2007/10/03)
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- Esterification in dry media using ferric perchlorate adsorbed on silica gel
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Adsorption of Fe(ClO4)3(H2O)6 onto chromatographic grade silica gel in the presence of alcohol ( to be used for esterification ) produces a supported reagent, Fe(ClO4)3(ROH)6/SiO2. This reagent, has been found effective for the rapid and high yield of esters, on grinding in the presence of carboxylic acids using pestle and mortar in the solid state.
- Parmar, Anupama,Kaur, Jatinder,Goyal, Rita,Kumar, Baldev,Kumar, Harish
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p. 2821 - 2826
(2007/10/03)
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- Compositions for reducing abnormal stimulation of endothelin receptors and novel compounds
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The invention relates to the new use and the new products of formula (I): STR1 in which: R1 =represents hydroxyl, alkyl, alkenyl, alkynyl, alkoxy, alkylthio, formyl, cycloalkyl, optionally interrupted by heteroatoms, R2, R3 represent in particular halogen, mercapto, acyl, carboxy, nitro, cyano, amino, carbamoyl, R4, --OR4 with R4 representing in particular hydrogen, alkyl, alkenyl, alkynyl, acyl, amino, --(CH2)m1 --S(O)m2 --X--R10 with m1=0 to 4, m2=0 to 2, X represents a single bond or --NH--, --NH--CO--, --NH--CO--NH--, and R10 represents alkyl, alkenyl or aryl, and Y represents optionally substituted aryl, these products being in all the isomer forms and the salts, as medicaments.
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- Fe2(SO4)3 · xH2O catalytic esterification of aliphatic carboxylic acids with alcohols
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Treatment of various alcohols with aliphatic carboxylic acids in the presence of a catalytic amount of Fe2(SO4)3 · xH2O to give the corresponding esters in good yields.
- Zhang, Gui-Sheng
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p. 1159 - 1162
(2007/10/03)
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- Macrocyclic oxamides
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Macrocyclic oxamides may be made easily, in good yield and in one step by reacting an oxalic compound, such as oxalic acid or oxalic esters, with a diamine, where the amine groups are separated by at least five atoms. The oxalic compounds may include, but are not limited to such materials as dimethyl oxalate and diethyl oxalate. The diamines may include, but are not limited to such materials as alkylenediamines; polyalkylene glycol diamines; alkyl-bis-(aminoalkyl)amines; imino bis-(alkyl)amines; and N,N' bis-(aminoalkyl)-N,N'-dialkylalkylenediamines and bis-(aminoalkyl)piperazines; and mixtures thereof. The macrocyclic oxamides made by this process may be used to selectively separate metal ions from solution, or complexed together with a metal ion act as a catalyst.
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- Synthesis and reactivity of bis(alkyloxalyl) and alkoxycarbonyl alkyloxalyl iron complexes and (R, R'=Me or Et): evidence for reductive elimination of oxalate
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The new complexes cis- (R=Me or Et) and cis- (R,R'=Me, Et or i-Pr) have been synthesized.The bis-(alkyloxalyl) complexes decarbonylate at +12 deg C to their alkoxycarbonyl alkyloxalyl homologues.The latter decompo
- Laurent, Pascale,Salauen, Jean-Yves,Gall, Gwenaeelle Le,Sellin, Murielle,Abbayes, Herve des
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p. 175 - 184
(2007/10/02)
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- Novel syntheses of oxamides, oxamates and oxalates from diisopropenyl oxalate
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Diisopropenyl oxalate, obtained by catalytic addition of oxalic acid to propyne, is a useful reagent for the access to a variety of α-dicarbonyl compounds such as oxamides, oxamates and oxalates, under very mild conditions.
- Neveux, Muriel,Bruneau, Christian,Lecolier, Serge,Dixneuf, Pierre H.
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p. 2629 - 2640
(2007/10/02)
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- Method of preparation of oxalic acid esters and amides
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A new process is described for the preparation of oxalic acid esters and amides of general formula (I) STR1 wherein Z designates an --OR or --NR1 R2 group, wherein R represents substituted or unsubstituted alkyl, alkenyl, cycloalkyl, aryl, or aryl-alkyl, R1 is hydrogen or substituted or unsubstituted alkyl, alkenyl, cycloalkyl, aryl, or aryl-alkyl, R2 represents substituted or unsubstituted alkyl, alkenyl, cycloalkyl, aryl, or aryl-alkyl, or R1 and R2 taken together with the adjacent nitrogen atom represent a saturated 5-, 6-, 7-, or 8-membered heterocyclic ring, which may contain an additional heteroatom selected from --O--, --S--, and --N(H, Alkyl)--, and optionally bear one or more alkyl or alkenyl substituents, and Z1 designates an --OR or --NR1 R2 group, wherein R, R1, and R2 are as defined before, or a group --NHCOCH3, which comprises the base-catalysed reaction of diacetyloxamide with an alcohol ROH or/and an amine HNR1 R2. The compounds of formula (I) have many industrial utilities, mainly as intermediates and stabilizers in the polymer field.
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- New method of preparation of oxalic acid esters and amides
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A new process is described for the preparation of oxalic acid esters and amides of general formula (I) Z- wherein, Z designates an -OR or -NR1R2 group, wherein R represents substituted or unsubstituted alkyl, alkenyl, cycloalkyl, aryl, or aryl-alkyl, R1 is hydrogen or substituted or unsubstituted alkyl, alkenyl, cycloalkyl, aryl, or aryl-alkyl, R2 represents substituted or unsubstituted alkyl, alkenyl, cycloalkyl, aryl, or aryl-alkyl, or R1 and R2 taken together with the adjacent nitrogen atom represent a saturated 5-, 6-, 7-, or 8-membered heterocyclic ring, which may contain an additional heteroatom selected from -O-, -S-, and -N(H, Alkyl)-, and optionally bear one or more alkyl or alkenyl substituents, and, Z1 designates an -OR or -NR1R2 group, wherein R, R1, and R2 are as defined before, or a group -NHCOCH3, which comprises the base-catalysed reaction of diacetyloxamide with an alcohol ROH or/and an amine HNR1R2. The compounds of formula (I) have many industrial utilities, mainly as intermediates and stabilizers in the polymer field.
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- Electro-organic reactions. Part 27. The mechanism of cathodic cleavage of activated esters; oxalates, squarates and oxamates
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Esters of oxalic acid, 3,4-dihydroxy-3-cyclobutene-1,2-dione (squaric acid), and oxamic acid, are reduced cathodically at modest potentials. In aprotic solvent, and on the cyclic voltammetric time scale, the esters are cleaved to the corresponding alkane. For oxalates, the mechanism of cathodic cleavage was investigated thoroughly by voltammetry, coulometry, and detailed product analysis. On the time scale of controlled potential electrolysis the rapid electrogenerated base-catalysed hydrolysis of the esters by adventitious water competes with cathodic cleavage. Similarly, rapid base-catalysed transesterification involving oxalates and added alcohols is observed which provides a practical method of reductively cleaving alcohols to alkanes by co-electrolysis of a mixture of alcohol and readily available oxalate (e.g. diethyloxalate). The leaving group in such cathodic fragmentation is the half-ester anion and the efficiency of reaction depends on the stability of the other, radical, fragment.
- Islam, Nazar-ul,Sopher, David W.,Utley, James H.P.
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p. 959 - 970
(2007/10/02)
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- Kinetic investigation of the mixed-metal bimolecular reductive eliminations in the reactions of EtOC(O)CH2M(CO)n or EtOC(O)M(CO)n (M = Co, n = 4; M = Mn, n = 5) with HCo(CO)4 or HMn(CO)5
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The alkyl- and acylmetal carbonyls EtOC(O)CH2M(CO)n and EtOC(O)M(CO)n (M = Co, n = 4; M = Mn, n = 5) react with HCo(CO)4 or HMn(CO)5 to yield ethyl acetate or ethyl formate and the corresponding binuclear metal carbonyl. Kinetic experiments support a mechanism according to which the reaction between a coordinatively unsaturated alkyl- or acylmetal carbonyl (formed by CO loss) and the metal carbonyl hydride is rate determining. The rate of this bimolecular reductive elimination step varies strongly and unexpectedly in the mixed-metal systems.
- Kovács, István,Hoff, Carl D.,Ungváry, Ferenc,Markó, László
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p. 1347 - 1350
(2008/10/08)
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- ACTIVATED METALLIC NICKEL IN PREPARATION OF SYMMETRICAL 1,3-DIARYLPROPAN-2-ONES FROM BENZYLIC HALIDES AND OXALYL CHLORIDES
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Oxidative addition of benzylic halides to nickel in the metallic state followed by insertion of carbon monoxide generated from alkyl oxalyl chlorides proceeded smoothly to give symmetrical 1,3-diarylpropan-2-ones in moderate yields.
- Inaba, Shin-ichi,Rieke, Reuben D.
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- 1,1'-OXALYLDIIMIDAZOLE, A NEW REAGENT FOR ACTIVATION OF CARBOXYLIC ACID
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Carboxylic acids and their salts are converted into the 1-acylimidazoles by the title reagent.This reaction is applied for esterification of fatty acids.
- Murata, Shizuaki
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p. 1819 - 1820
(2007/10/02)
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- FACILE ESTERIFICATION OF CARBOXYLIC ACIDS WITH ORGANOPHOSPHORUS REAGENTS. NOVEL APPLICATION OF ALKYLPHOSPHORIC ESTERS (APE)
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A mixture of alkyl phosphate esters (APE) obtained from P4O10 and alkanols taken in 1:6 mole ratio is an excellent esterification reagent for several classes of carboxylic acids.This new reagent offers several advantages compared to conventional reagents.
- Balasubramaniyan, V.,Bhatia, V. G.,Wagh, S. B.
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p. 1475 - 1485
(2007/10/02)
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- Dialkyl sulphites: Convenient Reagents for Esterification of Carboxylic Acids
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Several mono and dicarbocylic acids undergo esterification with dimethyl/ diethyl sulphite in the presence of traces of sulphuric acid in a one-pot reaction.
- Bhatia, V. G.,Shaik, A. S.,Tongare, D. B.,Balasubramaniyan, V.
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p. 259 - 260
(2007/10/02)
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- HYDROCONDENSATION OF CO2 III. REACTION OF CARBON DIOXIDE AND HYDROGEN WITH COPPER AND PALLADIUM BIS(DIPHENYLPHOSPHINO)-METHANE COMPLEXES
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New bis(diphenylphosphino)methane, (dpm) complexes of palladium have been prepared from PdCl2dpm, either by borohydride reduction of halide abstraction in the presence of added ligand.The catalytic activities of these and other polynuclear palladium and copper complexes in the CO2/H2 reaction have been tested.The results confirm the catalytic formation of alkyl formate and dialkyl formamide, but the juxtaposition of two or more metal centres does not appear to promote the catalytic formation of C2-compounds (oxalate).
- Denise, B.,Sneeden, R.P.A.
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p. 111 - 116
(2007/10/02)
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- Process for preparing diesters of malonic acid
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A process for preparing a diester of malonic acid which comprises reacting ketene and carbon monoxide with an ester of nitrous acid catalytically in the presence of metallic palladium or a salt thereof.
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- Preparing oxalic acid esters
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A method for the preparation of organic esters of oxalic acid by reaction of carbon monoxide under pressure with the corresponding alcohol is disclosed, the improvement consisting in the use of a quite particular catalyst system. The catalyst is a binary system in which the principal member is a palladium complex and the co-catalyst is a compound, preferably an organic compound having an acidic nature, no matter how weak.
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- A FACILE METHOD OF TRANSESTERIFICATION USING PHOSPHORUS YLID
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The transesterification of carboxylic esters catalysed with phosphorus ylid under neutral and mild conditions has been investigated.The reactions of esters having an electron withdrawing group with methanol proceeded rapidly and with high yield, whereas the reverse reactions proceeded slowly or not at all.
- Hashimoto, Shizunobu,Furukawa, Isao,Kuroda, Tomoyuki
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p. 2857 - 2860
(2007/10/02)
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- Process for preparing diesters of dicarboxylic acids
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A process for preparing a diester of a dicarboxylic acid having two more carbon atoms than the unsaturated hydrocarbon used as the starting material, which comprises subjecting an unsaturated hydrocarbon, carbon monoxide and an alcohol to reaction in the presence of a platinum group metal or a salt thereof; a compound selected from the group consisting of nitric acid, a nitrogen oxide and an ester of nitrous acid; and a halogen compound.
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- Process for the preparation of oxalate esters
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A process for the preparation of oxalate esters by reacting an alcohol with a mixture of carbon monoxide and oxygen in the presence of a catalytic mixture of: (a) a palladium, rhodium, platinum, copper, or cadmium metal salt compound or mixture thereof, (b) an aliphatic, cycloaliphatic, aromatic or heterocyclic amine or ammonia, (c) a copper (I), copper (II), iron (II) or iron (III) oxidant salt compound, and (d) an ammonium or substituted ammonium salt compound or acid with a counterion other than a halide. Alternatively a ligand or coordination complex compound of the metal salt compound may be employed.
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- Process for preparing oxalic acid and esters of same
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The present invention relates to a process for preparing oxalic acid and esters of oxalic acid. More particularly, this invention relates to a catalytic process for preparing oxalic acid and esters of same by the oxidative reaction, in a liquid phase, of carbon monoxide and water or alcohols with oxygen in the presence of redox systems. The catalyst systems used in accordance with this invention comprises a redox catalyst consisting essentially of a salt of Pd (II) and salts of a metal more electropositive than Pd having at least two oxidation states and, optionally, salts of alkaline metals, and co-catalytic amounts of at least one base having the formula R3 N in which the groups R which may be like or unlike and are selected from the group consisting of hydrogen and alkyl radicals having from 1 to 10 carbon atoms.
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- Preparation of oxalate esters from carbon monoxide and alcohol over a metal catalyst and a dione oxidant
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A process for the preparation of oxalate esters by the oxidative carbonylation of alcohols with carbon monoxide in the presence of a catalytic amount of copper, nickel, cadmium, cobalt or zinc metal salt catalyst and at least a stoichiometric amount of an unsubstituted or halogen substituted 2,5-cyclohexadiene-1,4-dione. High yields and selectivity of the oxalate ester, over the carbonate ester and CO2, are obtained and maximized by regulating temperature, carbon monoxide pressure and metal salt catalyst and by maintaining substantially anhydrous conditions.
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