502-56-7Relevant articles and documents
Adam,W.,Rucktaeschel,R.
, p. 4128 - 4133 (1972)
Kinetics of Valeric Acid Ketonization and Ketenization in Catalytic Pyrolysis on Nanosized SiO2, γ-Al2O3, CeO2/SiO2, Al2O3/SiO2 and TiO2/SiO2
Kulyk, Kostiantyn,Palianytsia, Borys,Alexander, John D.,Azizova, Liana,Borysenko, Mykola,Kartel, Mykola,Larsson, Mats,Kulik, Tetiana
, p. 1943 - 1955 (2017)
Valeric acid is an important renewable platform chemical that can be produced efficiently from lignocellulosic biomass. Upgrading of valeric acid by catalytic pyrolysis has the potential to produce value added biofuels and chemicals on an industrial scale. Understanding the different mechanisms involved in the thermal transformations of valeric acid on the surface of nanometer-sized oxides is important for the development of efficient heterogeneously catalyzed pyrolytic conversion techniques. In this work, the thermal decomposition of valeric acid on the surface of nanoscale SiO2, γ-Al2O3, CeO2/SiO2, Al2O3/SiO2 and TiO2/SiO2 has been investigated by temperature-programmed desorption mass spectrometry (TPD MS). Fourier transform infrared spectroscopy (FTIR) has also been used to investigate the structure of valeric acid complexes on the oxide surfaces. Two main products of pyrolytic conversion were observed to be formed depending on the nano-catalyst used—dibutylketone and propylketene. Mechanisms of ketene and ketone formation from chemisorbed fragments of valeric acid are proposed and the kinetic parameters of the corresponding reactions were calculated. It was found that the activation energy of ketenization decreases in the order SiO2>γ-Al2O3>TiO2/SiO2>Al2O3/SiO2, and the activation energy of ketonization decreases in the order γ-Al2O3>CeO2/SiO2. Nano-oxide CeO2/SiO2 was found to selectively catalyze the ketonization reaction.
Boosting activity of molecular oxygen by pyridinium-based photocatalysts for metal-free alcohol oxidation
Ma, Shuai,Cui, Jing-Wang,Rao, Cai-Hui,Jia, Meng-Ze,Chen, Yun-Rui,Zhang, Jie
supporting information, p. 1337 - 1343 (2021/02/26)
An eco-friendly and economical approach for the photocatalytic oxidation of organic inter-mediates by air under mild conditions is highly desirable in green and sustainable chemistry, where the photogeneration of active oxygen species plays a key role in improving conversion efficiency and selectivity. By using pyridinium derivatives as molecular mediators for electron transfer and energy transfer, the simultaneous activation of O2from air into superoxide radicals and singlet oxygen species can be achieved, and a photoinduced electron transfer catalytic system for the oxidation of alcohols has been developed. Thus, we have successfully simplified the complicated catalytic system into a single molecular catalyst without any additional noble metals and co-catalysts/additives. The current photocatalytic system shows high catalytic efficiency not only for aromatic alcohols but also for aliphatic alcohols that are generally difficult to undergo aerobic oxidation at room temperature under air atmosphere, representing an ideal photocatalytic platform for green and economical organic syntheses.
Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín
, p. 2084 - 2092 (2021/04/02)
Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
Ballaschk, Frederic,Kirsch, Stefan F.
supporting information, p. 5896 - 5903 (2019/11/11)
It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
