121-91-5Relevant articles and documents
Fabrication of three dimensional (3D) hierarchical Ag/WO3 flower-like catalyst materials for the selective oxidation of m-xylene to isophthalic acid
Acharyya, Shankha S.,Ghosh, Shilpi,Bal, Rajaram
, p. 5998 - 6001 (2015)
A three dimensional (3D) hierarchical silver supported tungsten oxide flower-like microsphere catalyst has been fabricated using a cationic surfactant CTAB. It was found that the crystal-splitting mechanism plays a key role in the formation of this flower-like structure. This catalyst was proved to be highly effective in the liquid phase selective oxidation of m-xylene to isophthalic acid.
Is carbon dioxide able to activate halogen/lithium exchange?
Durka, Krzysztof,Lulinski, Sergiusz,Dabrowski, Marek,Serwatowski, Janusz
, p. 4562 - 4570 (2014)
The unexpected effect of carbon dioxide on halogen-lithium exchange (HLE) reactions of selected haloarenes with tBuLi was investigated. In an aliphatic hydrocarbon solvent (pentane), the HLE does not occur at ca. -70 C but, surprisingly, pouring the mixture of reactants onto dry ice and subsequent aqueous acidic hydrolysis gave carboxylic acids resulting from the quench of the first-formed aryllithiums with carbon dioxide. This suggests that CO 2 acts as a promoter of the HLE and, subsequently, serves as an electrophile to trap the aryllithium intermediates that are generated in situ. Theoretical DFT calculations were used to develop a plausible mechanism for the reaction, which indicates that CO2 is a much weaker donor than tetrahydrofuran (THF) so the cleavage of inert tBuLi cubic tetramers into more reactive solvated dimeric species (tBuLi)2(CO2) 4 is disfavored by 42.8 kJ per mol of (tBuLi)4. It is possible that this deaggregation process occurs to some extent when a large excess of CO2 is used. Copyright
Modulating Reactivity and Selectivity of 2-Pyrone-Derived Bicyclic Lactones through Choice of Catalyst and Solvent
Pfennig, Toni,Chemburkar, Ashwin,Johnson, Robert L.,Ryan, Matthew J.,Rossini, Aaron J.,Neurock, Matthew,Shanks, Brent H.
, p. 2450 - 2463 (2018)
2-Pyrones, such as coumalic acid, are promising biobased molecules that through Diels-Alder reactions can provide access to a wide range of biobased chemicals, including molecules with functionality that are not easily accessible via conventional petrochemical routes. A complete reaction network and kinetic parameters for three individual diversification routes that start from a single bicyclic lactone produced via the Diels-Alder cycloaddition of coumalic acid and ethylene were examined experimentally and probed through complementary first-principle density functional theory (DFT) calculations, in situ nuclear magnetic resonance (NMR) spectroscopy, and thin film solid-state NMR spectroscopy. These experiments provide insights into the routes for several molecular structures from bicyclic lactones by leveraging Lewis or Br?nsted acid catalysts to selectively alter the reaction pathway. The bicyclic lactone bridge can be decarboxylated to access dihydrobenzenes at a substantially reduced activation barrier using γ-Al2O3 as the catalyst or selectively ring-opened via Br?nsted acids to yield 1,3-diacid six membered rings. DFT computations and microkinetic modeling in combination with experimental results provide molecular insights into the catalytically active sites on γ-Al2O3 and provide a general mechanism for the catalyzed bicyclic lactone decarboxylation in polar aprotic solvents, which involves CO2 extrusion as the kinetically relevant step. Solid-state NMR spectroscopy provides direct evidence of strong binding of the bicyclic lactone to the γ-Al2O3 surface, fully consistent with DFT simulation results and experimental reaction kinetics. In addition, the role of the solvent was examined and found to be an additional means to improve reaction rates and selectively produce alternative structures from the bicyclic intermediate. The rate of the decarboxylation reaction was increased dramatically by using water as the solvent whereas methanol acted as a nucleophile and selectively induced ring-opening, showing that both pathways are operative in the absence of catalyst. Taken together, the results demonstrate an approach for selective diversification of the coumalate platform to a range of molecules.
Palladium-catalyzed carbonylation of aryl iodides in aqueous media
Bumagin, N. A.,Nikitin, K. V.,Beletskaya, I. P.
, p. 563 - 566 (1988)
Carbonylation of ArI in aqueous media under 1 atm CO in the presence of phosphineless palladium complexes and some base leads to aromatic acids.
Photoinduced transformations of Acid Violet 7 and Acid Green 25 in the presence of TiO2 suspension
Fabbri,Calza,Prevot, A. Bianco
, p. 14 - 22 (2010)
An azo dye (Acid Violet 7) and an anthraquinone dye (Acid Green 25) were degraded in aqueous solution using titanium dioxide as photocatalyst. Their fate was studied through dyes decomposition, identification of the main and secondary transformation produ
Photo-induced deep aerobic oxidation of alkyl aromatics
Wang, Chang-Cheng,Zhang, Guo-Xiang,Zuo, Zhi-Wei,Zeng, Rong,Zhai, Dan-Dan,Liu, Feng,Shi, Zhang-Jie
, p. 1487 - 1492 (2021/07/10)
Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical industry. Presently, the industrial manufacture of benzoic acids and benzene polycarboxylic acids (BPCAs) is mainly based on the deep oxidation of polyalkyl benzene, which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting MeBr and corrosion hazards of production equipment. In this report, photo-induced deep aerobic oxidation of (poly)alkyl benzene to benzene (poly)carboxylic acids was developed. CeCl3 was proved to be an efficient HAT (hydrogen atom transfer) catalyst in the presence of alcohol as both hydrogen and electron shuttle. Dioxygen (O2) was found as a sole terminal oxidant. In most cases, pure products were easily isolated by simple filtration, implying large-scale implementation advantages. The reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks. [Figure not available: see fulltext.].
Photoinduced FeCl3-Catalyzed Alkyl Aromatics Oxidation toward Degradation of Polystyrene at Room Temperature?
Zhang, Guoxiang,Zhang, Zongnan,Zeng, Rong
supporting information, p. 3225 - 3230 (2021/09/28)
While polystyrene is widely used in daily life as a synthetic plastic, the subsequently selective degradation is still very challenging and highly required. Herein, we disclose a highly practical and selective reaction for the catalytically efficient oxidation of alkyl aromatics (including 1°, 2°, and 3° alkyl aromatics) to carboxylic acids. While dioxygen was used as the sole terminal oxidant, this protocol was catalyzed by the inexpensive and readily available ferric compound (FeCl3) with irradiation of visible light (blue LEDs) under only 1 atmosphere of O2 at room temperature. This system could further facilitate the selective degradation of polystyrene to benzoic acid, providing an important and practical tool to generate high-value chemical from abundant polystyrene wastes.
MOF-Zn-NHC as an efficient N-heterocyclic carbene catalyst for aerobic oxidation of aldehydes to their corresponding carboxylic acids: Via a cooperative geminal anomeric based oxidation
Babaee, Saeed,Zarei, Mahmoud,Zolfigol, Mohammad Ali
, p. 36230 - 36236 (2021/12/02)
As an efficient heterogenous N-heterocyclic carbene (NHC) catalyst, MOF-Zn-NHC was used in the aerobic oxidation of aryl aldehydes to their corresponding carbocyclic acids via an anomeric based oxidation. Features such as mild reaction conditions and no need for a co-catalyst or oxidative reagent can be considered as the major advantages of the presented method in this study. This journal is
Silica-Mediated Monohydrolysis of Dicarboxylic Esters
Dyker, Gerald
supporting information, p. 6773 - 6776 (2021/12/31)
A new method for the monohydrolysis of dicarboxylic esters is presented, involving as key step a silanolysis at elevated temperatures at the silica gel surface. In the second step, the surface bound silyl esters are cleaved off under mild conditions, giving a straightforward and fast access to half esters. Based on recovered starting material generally yields well above 70 % are achieved, both, with stiff aromatic as well as flexible aliphatic substrates, as long as the ester groups involved are remote enough from each other. Otherwise competing reactions are becoming determinative, anhydride formation in the case of phthalates and decarbonylative fragmentation in the case of malonates. The new method was also successfully tested on a multigram scale with a minimalistic apparatus setup.
Fuel-Driven Dynamic Combinatorial Libraries
Bergmann, Alexander M.,Boekhoven, Job,Kriebisch, Christine M. E.
, p. 7719 - 7725 (2021/05/26)
In dynamic combinatorial libraries, molecules react with each other reversibly to form intricate networks under thermodynamic control. In biological systems, chemical reaction networks operate under kinetic control by the transduction of chemical energy. We thus introduced the notion of energy transduction, via chemical reaction cycles, to a dynamic combinatorial library. In the library, monomers can be oligomerized, oligomers can be deoligomerized, and oligomers can recombine. Interestingly, we found that the dynamics of the library's components were dominated by transacylation, which is an equilibrium reaction. In contrast, the library's dynamics were dictated by fuel-driven activation, which is a nonequilibrium reaction. Finally, we found that self-assembly can play a large role in affecting the reaction's kinetics via feedback mechanisms. The interplay of the simultaneously operating reactions and feedback mechanisms can result in hysteresis effects in which the outcome of the competition for fuel depends on events that occurred in the past. In future work, we envision diversifying the library by modifying building blocks with catalytically active motifs and information-containing monomers.
