15022-08-9Relevant academic research and scientific papers
Highly efficient Tsuji-Trost allylation in water catalyzed by Pd-nanoparticles
Llevot,Monney,Sehlinger,Behrens,Meier
, p. 5175 - 5178 (2017)
Palladium nanoparticles stabilized by poly(vinylpyrrolidone) catalyze Tsuji-Trost allylations in water with very high turnover numbers. The di-allylation of methylene active compounds and the allylation of bio-based phenols was performed in high yield. The allylation of lignin showed a high selectivity towards the phenolic OH groups.
Acetals of N,N-dimethylformamides: Ambiphilic behavior in converting carbon dioxide to dialkyl carbonates
Takada, Yuki,Matsuoka, Aki,Du, Ya,Naka, Hiroshi,Saito, Susumu
, p. 146 - 147 (2013)
Carbon dioxide is immobilized into dialkyl carbonate using acetals of N,N-dimethylformamide under atmospheric pressure. No special treatment with tailor-made catalysts is needed. Use of dimethyl sulfoxide as a solvent is critical. An ambiphilic mechanism is proposed for the direct synthesis of dialkyl carbonates from acetals and carbon dioxide.
Direct Synthesis of Diallyl Carbonate Via Urea Transesterification with Allyl Alcohol Over Metal Chlorides
Wang, Dengfeng,Zhang, Xuelan,Luo, Hainan,Wei, Shuwei,Zhao, Xueying
, p. 1067 - 1074 (2019)
A promising technique was studied towards diallyl carbonate (DAC) manufacture via urea transesterification with allyl alcohol over several metallic chlorides. It was revealed that the intermediate allyl carbamate (AC) was first generated via urea mono-alcoholysis with high yield, and subsequently AC further reacted with another allyl alcohol molecule to produce DAC. All the metal halides were evaluated for the overall reaction and the reaction of AC and allyl alcohol, respectively. This work found that the catalytic ability of catalysts originated from metal ions. Importantly, the highest yield of DAC could be achieved using LaCl3 as catalyst. In addition, the activation patterns of reactants were investigated using in situ FT-IR measurement. Based on the characterization results of X-ray power diffraction and elemental analysis of the lanthanum species, separated from the reaction conduced over LaCl3, a possible reaction mechanism was speculated. Graphical Abstract: [Figure not available: see fulltext.].
Synthesis of Carbonate Esters by Carboxymethylation Using NaAlO2 as a Highly Active Heterogeneous Catalyst
Ramesh, Sreerangappa,Indukuri, Kiran,Riant, Olivier,Debecker, Damien P.
, p. 1846 - 1851 (2019/01/04)
Sodium aluminate is presented as a highly active heterogeneous catalyst that is able to convert a range of alcohols into the corresponding unsymmetrical carbonate esters by reaction with dimethyl carbonate. Preparing NaAlO2 via spray drying boosts the basic properties and the activity of the catalyst.
PROCESS FOR THE PREPARATION OF ORGANIC CARBONATE DERIVATES
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Page/Page column 27; 28, (2017/04/11)
The present invention relates in general terms to a new process for the preparation of organic carbonate derivatives, cyclic or linear by a trans carbonation reaction between PCC and a suitable aliphatic alcohol, in the presence of a homogeneous or heterogeneous basic catalyst; the process allows to optimize yields and selectivities of the obtained products, especially in the case of the preparation of symmetrical linear or cyclic carbonates starting from the corresponding primary alcohols.
The design of efficient carbonate interchange reactions with catechol carbonate
Tabanelli,Monti,Cavani,Selva
, p. 1519 - 1528 (2017/05/01)
Catechol carbonate (CC) has been investigated as an innovative and highly active reactant for carbonate interchange reactions (CIRs). Under mild conditions (atmospheric pressure, and 60-80°C), the selective synthesis of symmetric aliphatic carbonates (ROCO2R) has been achieved by the reaction of a slight excess of both primary and secondary alcohols with CC in the presence of NaOMe or MgO as a catalyst. Quantitative conversions have been reached in only 1 hour and products have been isolated in yields of up to 58% for dibutylcarbonate. Of note is that the reaction of glycerol with CC also proceeded under similar conditions (40-60°C, 1 atm) to afford glycerol carbonate (96-98%). The comparison of the reactivity of CC with that of conventional dialkyl carbonates, including dimethyl carbonate (DMC) and ethylene carbonate (EC), proved the superior performance of CC in all the investigated CIR processes. Accordingly, a mechanism has been formulated based on the leaving group ability of a catecholate anion originating from CC.
Masked N-Heterocyclic Carbene-Catalyzed Alkylation of Phenols with Organic Carbonates
Lui, Matthew Y.,Yuen, Alexander K. L.,Masters, Anthony F.,Maschmeyer, Thomas
, p. 2312 - 2316 (2016/10/24)
An easily prepared masked N-heterocyclic carbene, 1,3-dimethylimidazolium-2-carboxylate (DMI-CO2), was investigated as a “green” and inexpensive organocatalyst for the alkylation of phenols. The process made use of various low-toxicity and renewable alkylating agents, such as dimethyl- and diethyl carbonate, in a focused microwave reactor. DMI-CO2 was found to be a very active catalyst and excellent yields of a range of aryl alkyl ethers were obtained under relatively benign conditions. The observed difference in the conversion behavior of phenol methylation, in the presence of either the carbene or 1,8-diazabicycloundec-7-ene (DBU) catalyst, was rationalized on the basis of mechanistic investigations. The primary mode of action for the N-heterocyclic carbene is nucleophilic catalysis. Activation of the dialkyl carbonate electrophile results in concomitant evolution of an organo-soluble alkoxide, which deprotonates the phenolic starting material. In contrast, DBU is initially protonated by the phenol and thus consumed. Subsequent regeneration and participation in nucleophilic catalysis only becomes significant after some phenolate alkylation occurs.
Organic carbonate synthesis from CO2 and alcohol over CeO 2 with 2-cyanopyridine: Scope and mechanistic studies
Honda, Masayoshi,Tamura, Masazumi,Nakagawa, Yoshinao,Nakao, Kenji,Suzuki, Kimihito,Tomishige, Keiichi
, p. 95 - 107 (2014/09/17)
The combination system of CeO2-catalyzed carboxylation and 2-cyanopyridine hydration (CeO2 + 2-cyanopyridine system) is effective for the direct synthesis of organic carbonates from CO2 and alcohols. This catalyst system can be applied to various alcohols to afford the corresponding carbonates in high alcohol-based yields. The hydration of 2-cyanopyridine over CeO2 rapidly proceeds under the low concentration of water, which can remove the water from the reaction media. Since the reaction is limited by the chemical equilibrium, the removal of water remarkably shifts the chemical equilibrium to the carbonate side, leading to high carbonate yields. In addition, 2-picolinamide that is produced by hydration of 2-cyanopyridine forms an intramolecular hydrogen bonding between H atom of the amide group and N atom of the pyridine ring, which weakens the adsorption of 2-picolinamide on CeO2 by reduction of the acidity. The reaction mechanism of DMC formation in CeO2 + 2-cyanopyridine system is also proposed.
Introducing catalytic lossen rearrangements: Sustainable access to carbamates and amines
Kreye, Oliver,Wald, Sarah,Meier, Michael A. R.
supporting information, p. 81 - 86 (2013/03/13)
A new, highly efficient and environmentally benign catalytic variant of the Lossen rearrangement is described. Dimethyl carbonate (DMC) as green activation reagent of hydroxamic acids in presence of catalytic amounts of tertiary amine bases {1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-biazabicyclo 5.4.0 undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), and triethylamine} and small quantities of methanol initiate the rearrangement. Methyl carbamates were obtained in good to moderate yields when aliphatic hydroxamic acids were employed in this catalytic Lossen rearrangement; under the same conditions aromatic hydroxamic acids yielded anilines. Notably, the mixture of DMC/methanol was recycled several times without observing decreased yields, thus minimizing the produced waste. Moreover, several other organic carbonates were successfully employed in the introduced catalytic Lossen rearrangement procedure. Copyright
TBD catalysis with dimethyl carbonate: A fruitful and sustainable alliance
Mutlu, Hatice,Ruiz, Johal,Solleder, Susanne C.,Meier, Michael A. R.
supporting information, p. 1728 - 1735 (2013/02/22)
This work presents the synthesis of unsymmetric and symmetric organic carbonates as well as the synthesis of polycarbonates in an efficient and sustainable approach. All reactions were carried out at atmospheric pressure at 80°C and the use of classic toxic and harmful chemicals, such as phosgene and carbon monoxide, was avoided. The key finding of this manuscript is that the use of 1,5,7-triazabicyclo[4.4.0]dec-5-ene, TBD, an organocatalyst, in combination with dimethyl carbonate (DMC), a non-toxic and renewable starting material, allows the synthesis of the mentioned unsymmetric carbonates in yields of up to 98% under optimized conditions. The structure of the alcohols used for this approach was found to influence the DMC-ROH ratio required to maximize the yield of the desired structure. Finally, the results obtained for the synthesis of low molecular weight building blocks could be transferred to the catalytic synthesis of high molecular weight polycarbonates. The Royal Society of Chemistry.
